http://informahealthcare.com/jmf ISSN: 1476-7058 (print), 1476-4954 (electronic) J Matern Fetal Neonatal Med, Early Online: 1–7 ! 2015 Informa UK Ltd. DOI: 10.3109/14767058.2015.1035640
ORIGINAL ARTICLE
Twin pregnancy outcomes after increasing rate of vaginal twin delivery: retrospective cohort study in a Hong Kong regional obstetric unit
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Hiu Tung Tang, Ah Lai Liu, Sum Yee Chan, Chin Ho Lau, Wai Kuen Yung, Wai Lam Lau, and Wing Cheong Leung Department of Obstetrics and Gynaecology, Kwong Wah Hospital, Hong Kong
Abstract
Keywords
Objective: To determine any change in adverse neonatal/maternal outcomes after increasing the rate of vaginal twin delivery by comparing vaginal twin delivery and caesarean delivery with our previous cohort study. Methods: In a retrospective cohort study, all twins booked at a Hong Kong regional obstetrics unit were evaluated during a 3-year period from 1 April 2009 to 31 March 2012. Results: Out of the 269 sets of twins who eventually delivered in our unit, 68 (25.3%) of them were delivered vaginally, compared to 15.8% in our previous cohort study (p ¼ 0.02). For those who were suitable for vaginal delivery, significantly more women attempted vaginal delivery: 93/133 (69.9%) versus 47/100 (47%) (p ¼ 0.0005). The success rate for vaginal delivery and rate of requiring caesarean delivery for the 2nd twin were similar between these two periods. There were significantly more 2nd twins with cord blood pH57.2 when both twins were delivered by vaginal delivery. Otherwise, there was no significant difference between other neonatal/ maternal morbidities. Conclusion: With proper counseling, significantly more women who were suitable for vaginal twin delivery would opt to do so. There was no significant increase in neonatal/maternal morbidities despite the increased rate of vaginal twin delivery.
Caesarean delivery, maternal outcome, neonatal outcome, twins, vaginal delivery
Introduction With the increasing popularity of artificial reproductive technique, twin pregnancies occur more frequently now than in the past, and complicate approximately 2–3% of all births [1,2]. They are responsible for 10% of all perinatal mortality [3]. Previously several cohort studies have shown a reduced risk of adverse perinatal outcomes for both twins, or for the second twin, when twins at or near term were delivered by means of elective caesarean delivery (CD) [4–7]. However, there were also cohort studies, meta-analyses [8–13], and most importantly, a recent multi-centered large randomized controlled trial showing the opposite result [14]. Further, our unit also did a cohort study evaluating the mode of delivery and associated pregnancy outcomes of 197 sets of twins booked in our unit during 2006–2009. A high CD rate (82%) was observed in our unit. Except for higher frequency of sepsis and cord blood acidosis in the 2nd twin delivered vaginally, there were no significant differences in neonatal morbidity between the groups that attempted vaginal delivery or requested caesarean delivery [15].
Address for correspondence: Dr. Hiu Tung Tang, Department of Obstetrics and Gynaecology, N10, Kwong Wah Hospital, Waterloo Road, Hong Kong. Tel: +852 94961068/+852 35177983. Fax: +852 35177149. E-mail: [email protected]
History Received 1 November 2014 Revised 8 March 2015 Accepted 26 March 2015 Published online 20 April 2015
With the result of our cohort study, our unit from 2010 onwards re-promoted vaginal delivery for uncomplicated twin pregnancies if the first twin was in cephalic presentation. A standardized counseling approach for the mode of delivery was used in a designated twin clinic, along with the addition of a labor ward consultant. We subsequently observed a rebound increase in vaginal twin delivery rate since 2008, and it gradually climbed up to as high as 40% in 2012 (Figure 1). This observation has recently been published in the work by Tang et al. [16]. In view of this change in the trend of mode of twin delivery, we decided to have another cohort study subsequent to our previous cohort in order to study any difference in pregnancy outcomes after increasing the rate of vaginal twin delivery.
Materials and methods This was a retrospective cohort study, reviewing all twin pregnancies booked during the 3-year period from 1 April 2009 to 31 March 2012. In our unit, all booked twin pregnancies were recorded in a twin pregnancy clinic registry [17]. The pregnancies were then followed up in a specialized twin pregnancy clinic by a dedicated team of obstetricians and midwives. The team of obstetricians was specialized in maternal fetal medicine. Follow-up intervals were guided by the department protocol (available from the corresponding
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Figure 1. Vaginal delivery rate (%) of Twins in a regional Obstetric Unit in Hong Kong (1993–2012) [13].
author). Ultrasound examinations were performed on monochorionic twins every 2–3 weeks until 30 weeks of gestation, and at each visit after 30 weeks. For dichorionic twins, ultrasound examinations were performed monthly till 30 weeks, and at each visit after 30 weeks. When approaching term, the responsible obstetrician in the twin clinic discussed the mode of delivery with the mother and her partner (if available). In the absence of other contraindications to a trial of labor, vaginal twin delivery was considered an appropriate option for all dichorionic diamniotic(DCDA) and monochorionic diamniotic(MCDA) twin pregnancies if the first twin was in cephalic presentation, and no previous uterine scar. Induction of labor would be offered at 37–38-week gestation for MCDA as well as DCDA twins [18,19]. CD was recommended for all monochorionic monoamniotic(MCMA) twin pregnancies. We used the same method in data collection as in our previous cohort study [15]. Corresponding twin pregnancies were identified from the twin pregnancy clinic registry. Antenatal clinical notes, in-patients clinical notes and computer records of the women and their babies were reviewed in details. Moreover, women who were not booked but delivered in our unit during that period of time were also identified through our delivery registry in labor ward. For women who did not deliver in our unit, they would be contacted upon defaulting follow-up and their mode of delivery would be recorded in the clinical notes. Three investigators (HT, SY, CH) were involved in note review and data collection with agreement of definition used in data entry to avoid discrepancy during interpretation. A detailed data entry form (which was similar to that used in previous cohort study) was filled in for each set of twins. Maternal background information, including demographic data, medical history, obstetrical history, type of conception, antenatal and intrapartum complications, fetal presentations, mode of delivery, placental chorionicity, as well as neonatal and maternal outcomes were filled in for each set of twins. Neonatal outcomes included birth weight, gender, gestation at delivery, Apgar scores, cord blood pH, neonatal intensive care unit (NICU) admission,
birth trauma and neonatal morbidity. Neonatal morbidity was defined as respiratory morbidity, neurological morbidity, sepsis, or neonatal jaundice. Respiratory morbidity included respiratory distress syndrome, transient tachypnoea of the newborn, apnoea of prematurity, or pneumothorax. Neurological morbidity included intraventricular hemorrhage. Sepsis included those with clinical sepsis, cellulitis or necrotising enterocolitis. Maternal outcomes included blood loss, receipt of a blood transfusion, having compression sutures or hysterectomy to control postpartum hemorrhage. Statistical analysis was performed using the SPSS (Statistical Package for the Social Science Mac Version 22, Chicago, IL). Differences between categorical variables were analyzed using the Chi-square test. Differences between continuous variables were analyzed by independent samples t-test. p value 50.05 was considered statistically significant. Logistic regression was used to evaluate the relationship between education, history of vaginal delivery, type of conception, chorionicity and presentation of the 2nd twin, and the mother’s choice to attempt vaginal delivery or request caesarean delivery. Approval of the study was granted by the local research ethics committee (Ref no: KW/EX-14-101(75-16)). As this was a retrospective cohort study and the data were obtained from patients’ records, management of patient was not involved, and thus written informed consent was not needed in our study.
Result A total of 317 twins were booked in our unit during 1 April 2009 to 31 March 2012. Six non-booked cases were identified. Sixteen mothers defaulted our follow up and cannot be contacted. Eighteen of them delivered in private hospitals, all by CD. Twenty mothers delivered in other public hospitals: 4 via vaginal delivery and 16 via caesarean delivery. After excluding the 16 twin deliveries who defaulted from our study, we found that 72 sets of twins (23.5%) were delivered vaginally, 4 sets of twins involved vaginal delivery
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DOI: 10.3109/14767058.2015.1035640
Effect of vaginal twin delivery
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Figure 2. Flowchart of the number of twin pregnant mothers who were booked and finally delivered in our unit during 1 April 2009 to 31 March 2012.
of 1st twin and emergency CD of 2nd twin (1.3%). Twohundred thirty-one sets of twins (75.2%) were delivered by CD. Compared to our previous cohort study [15], we noted a substantial increase in the overall number of twins, and percentage of vaginal twin deliveries (16.9% versus 23.9%, p ¼ 0.0725). Two-hundred sixty-nine sets of twins were delivered in our unit during this period of time. Sixty-eight sets of twins (25.3%) were delivered by vaginal delivery, and four sets of twins (1.4%) involved vaginal delivery of first twin and emergency CD of 2nd twin. One hundred ninety-seven sets (73.2%) were delivered by CD for both twins. In our previous cohort study, only 15.8% of twins were delivered vaginally. A significant increase of vaginal delivery rate was identified (p ¼ 0.0245). Among those suitable for vaginal delivery, 93 out of 133 mothers (69.9%) attempted vaginal delivery in our current study, while only 47 out of 100 mothers (47%) attempted vaginal delivery in our previous cohort (p ¼ 0.0005). Success rate was found to be similar (73.1% versus 70.2%), and risk of requiring CD for 2nd twin did not significantly increase (4.3% versus 4.3%) (Figure 2). Reasons for choosing caesarean delivery were also evaluated. The most common indications for CD were
malpresentation of first twin (33.6%) and maternal request (20.3%). This group of maternal requests received CD, despite them having the following three conditions which were suitable for vaginal delivery: (1) DCDA or MCDA twin pregnancies, (2) the first twin was in cephalic presentation, and (3) there was no other obstetrics indication to have a CD. Excluding maternal request and malpresentation, other indications for CD included intrauterine growth retardation (14.7%), previous caesarean delivery (3.6%), no progress in labour (3.6%), pre-eclampsia (3%), and placental praevia (3%). Intrauterine growth retardation was defined as estimated fetal weight510th percentile of our local growth chart with or without abnormal Doppler. We realized that both guidelines published by ACOG and SOGC suggested that twin pregnancy was not a contraindication for attempting vaginal birth after previous caesarean (VBAC), while RCOG advised a cautious approach when considering VBAC for twins [20–22]. In our unit, previous CD is still an indication for repeat CD. However, in our previous cohort study, 32.7% of caesarean delivery was done purely for maternal request only (p ¼ 0.008). For those suitable for vaginal delivery, significantly more multiparous women (p ¼ 0.002), and women with second twin in cephalic presentation (p ¼ 0.005) were willing to attempt
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Table 1. Comparison of neonatal outcome between the pregnant mothers (considered suitable for vaginal delivery) who attempted vaginal delivery and planned caesarean delivery. Total number (133)
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Planned vaginal delivery (93)
Chorionicity of Twin (Yes – MCDA, No – DCDA) 1st twin: Mean birth weight (kg) 2nd twin: Mean birth weight (kg) 1st twin: cord blood pH 57.2 2nd twin cord blood pH 57.2 1st twin AS at 5 min: 4 7 2nd twin AS at 5 min: 4 7 1st twin NICU admission 2nd twin NICU admission Mean gestation age (week) Gestation at delivery 532 1st twin birth trauma 2nd twin birth trauma 1st twin neonatal resuscitation 2nd twin neonatal resuscitation 1st twin respiratory morbidity 1st twin sepsis 1st twin neonatal jaundice 1st twin neurological morbidity 2nd twin respiratory morbidity 2nd twin sepsis 2nd twin neonatal jaundice 2nd twin neurological morbidity
Planned caesarean delivery (40)
Yes
No
Yes
26 (27.7%)
58 (62.3%)
5 (12.5%)
2.34 (95% CI: 2.24–2.43) 2.39 (95% CI: 2.29–2.49) 7 (7.5%) 82 (88.2%) 13 (14.0%) 78 (83.9%) 1 (1%) 92 (99%) 2 (2.1%) 91 (97.9%) 0 (0%) 93 (100%) 1 (1%) 92 (99%) 8 (8.6%) 85 (91.4%) 9 (9.7%) 84 (90.3%) 35.9 (95% CI: 35.4–36.5) 7 (7.5%) 86 (92.5%) 4 (4.3%) 89 (95.7%) 2 (2.1%) 91 (97.9%) 6 (6.5%) 87 (93.5%) 7 (7.5%) 86 (88.2%) 20 (21.5%) 73 (78.5%) 8 (8.6%) 85 (91.4%) 17 (18.3%) 76 (82.7%) 5 (5.4%) 88 (94.6%) 20 (21.5%) 73 (78.5%) 10 (10.7%) 83 (89.2%) 13 (14.0%) 80 (86.0%) 3 (3.2%) 90 (96.8%)
No 32 (80%)
2.46 (95% CI: 2.34–2.58) 2.40 (95% CI 2.29–2.50) 3 (7.5%) 35 (87.5%) 2 (5%) 37 (92.5%) 0 (0%) 40 (100%) 0 (0%) 40 (100%) 0 (0%) 40 (100%) 0 (0%) 40 (100%) 0 (0%) 40 (100%) 1 (2.6%) 39 (93.7%) 36.6 (95% CI: 36.2–37.1) 0 (0%) 40 (100%) 0 (0%) 40 (100%) 0 (0%) 40 (100%) 0 (0%) 40 (100%) 1 (2.6%) 39 (93.7%) 5 (12.5%) 35 (87.5%) 5 (12.5%) 35 (87.5%) 11 (27.5%) 29 (72.5%) 0 (0%) 40 (100%) 4 (10%) 36 (90%) 4 (10%) 36 (90%) 4 (10%) 36 (90%) 1 (2.6%) 39 (93.7%)
p value 0.045 0.17 0.97 0.984 0.324 0.51 0.35 NA 0.51 0.056 0.15 0.163 0.075 0.183 0.35 0.1 0.264 0.223 0.488 0.232 0.135 0.114 0.897 0.529 40.99
MCDA – Monochorionic Diamniotic; DCDA – Dichorionic Diamniotic; AS – Apgar Score; NICU – Neonatal Intensive Care Unit.
vaginal delivery. Moreover, our multiparous women had a higher successful vaginal rate (88%) compared to nulliparous women (60%) (p ¼ 0.0023), while for the presentation of the 2nd twin, there was no significant difference in the success rate (76.1% versus 65.4%) (p ¼ 0.31). Although apparently more DCDA twins ended up with CD, after evaluating with multinomial logistic linear regression and controlling other factors such as history of vaginal delivery, presentation of 2nd twin, education level of mother and mode of conception, chorionicity was not significant. Neonatal outcomes and maternal outcomes were evaluated in twoways. Firstly, it was compared between those who attempted vaginal delivery and planned caesarean delivery for the pregnant mothers who were considered suitable for vaginal delivery. No significant difference between the AS, need for NICU admissions/neonatal resuscitation/respiratory/ sepsis/neurological morbidity was identified (Table 1). Secondly, neonatal outcomes were compared between those with vaginal delivery and caesarean delivery for both twins. Significantly more 2nd twins had cord blood pH 57.2 in vaginal twin deliveries. Otherwise, no significant difference between the need for NICU admissions/neonatal resuscitation/respiratory/sepsis/neurological morbidity was seen (Table 2). In our study, there were four pairs of twins who attempted vaginal delivery for 1st twin but required caesarean delivery for 2nd twin. Hand presentation of the 2nd twin was noted in one of the cases while there was another case where the second twin was noted to be in oblique breech position with
the cervix being clamped down to 5 cm. Amniotic membrane remained intact and syntocinon drip was not given in both cases. In the other 2 cases, 2nd twins were in cephalic presentation, uterine contractions subsided after delivery of 1st twins, amniotomy was not performed but a syntocinon drip was subsequently given; there was no strong uterine contraction in both cases despite syntocincon administration, and cervix remained 2 and 5 cm dilated, respectively, after 30 min. Emergency CD were arranged for these four cases. They all had good outcomes. None of the babies required NICU admissions or developed sepsis, respiratory, neurological or other neonatal complications except neonatal jaundice. The cord blood pHs of the 2nd twins were 7.13, 7.14, 7.26 and 7.28. Maternal outcome is outlined in Table 3. There was no statistically significant difference in the incidence of postpartum hemorrhage or blood transfusions. All patients requiring compression sutures were in the caesarean group, though the difference was not statistically significant. One patient required hysterectomy due to massive postpartum hemorrhage and she was in the caesarean group.
Discussion In 2000, Term Breech Trial [23] was published. The result indicated that planned caesarean delivery was associated with a better perinatal outcome. After this publication, rates of vaginal breech delivery decreased significantly, and rates of vaginal twin delivery also decreased throughout the
Effect of vaginal twin delivery
DOI: 10.3109/14767058.2015.1035640
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Table 2. Comparison of neonatal outcome between the pregnant mothers with vaginal delivery and caesarean delivery for both twins. Total number (269) Vaginal delivery for both (68)
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Yes Chorionicity of Twin (Yes – MCDA, No – DCDA) 1st twin: Mean birth weight (kg) 2nd twin: Mean birth weight (kg) 1st twin: cord blood pH 57.2 2nd twin cord blood pH 57.2 1st twin AS at 5 min: 4 7 2nd twin AS at 5 min: 4 7 1st twin NICU admission 2nd twin NICU admission Mean gestation age (week) Gestation at delivery 532 1st twin birth trauma 2nd twin birth trauma 1st twin neonatal resuscitation 2nd twin neonatal resuscitation 1st twin respiratory morbidity 1st twin sepsis 1st twin neonatal jaundice 1st twin neurological morbidity 2nd twin respiratory morbidity 2nd twin sepsis 2nd twin neonatal jaundice 2nd twin neurological morbidity
Caesarean delivery for both (197) No
Yes
22 (32.3%) 38 (55.9%) 2.28 (95% CI: 2.16–2.38) 2.32 (95% CI: 2.20–2.43) 5 (7.4%) 60 (88.2%) 10 (14.7%) 56 (82.4%) 1 (1.5%) 67 (98.5%) 2 (2.9%) 66 (97.1%) 0 (0%) 68 (100%) 1 (1.5%) 67 (98.5%) 6 (9.7%) 62 (90.3%) 6 (9.7%) 62 (90.3%) 35.8 (95% CI 35.1–36.5) 6 (9.7%) 62 (90.3%) 2 (2.9%) 66 (97.1%) 2 (2.9%) 66 (97.1%) 4 (5.9%) 64 (94.1%) 6 (9.7%) 62 (90.3%) 15 (28.3%) 53 (71.7%) 5 (7.4%) 63 (92.6%) 13 (19.1%) 55 (80.9%) 4 (5.9%) 64 (94.1%) 16 (23.6%) 52 (76.4%) 7 (10.3%) 61 (89.7%) 11 (16.2%) 57 (83.8%) 2 (2.9%) 66 (97.1%)
No
p value
40 (16.2%) 141 (71.6%) 2.35 (95% CI: 2.28–2.42) 2.28 (95% CI: 2.21–2.36) 9 (4.6%) 185 (93.9%) 10 (5.1%) 185 (93.9%) 1 (0.5%) 196 (99.5%) 3 (1.5%) 194 (98.5%) 0 (0%) 194 (98.5%) 1 (0.5%) 196 (99.5%) 24 (10.7%) 173 (87.8%) 35 (17.8%) 162 (82.2%) 36 (95% CI 35.7–36.3) 11 (5.6%) 186 (94.4%) 4 (20.3%) 193 (79.7%) 0 (0%) 197 (100%) 13 (6.6%) 184 (93.4%) 16 (8.1%) 181 (91.9%) 47 (23.9%) 150 (76.1%) 24 (12.2%) 173 (87.8%) 43 (21.8%) 154 (78.2%) 9 (4.6%) 188 (95.4%) 52 (26.4%) 142 (72.1%) 28 (14.2%) 169 (84.7%) 39 (19.8%) 158 (80.2%) 12 (6.1%) 185 (93.9%)
0.04 0.28 0.62 0.3502 0.014 0.4481 0.6053 40.99 0.4481 0.5141 0.0836 0.507 0.7872 0.6484 0.0651 40.99 0.8037 0.8685 0.3685 0.7317 0.7453 0.6335 0.5341 0.5920 0.5295
MCDA – Monochorionic Diamniotic; DCDA – Dichorionic Diamniotic; AS – Apgar Score; NICU – Neonatal Intensive Care Unit.
Table 3. Comparison of maternal outcomes. Planned vaginal delivery (93) Maternal outcome
Yes
PPH 4500mL 23 (24.7%) PPH requiring extra drugs 7 (7.5%) PPH requiring 0 (0%) compression suture PPH requiring hysterectomy 0 (0%) Need for blood transfusion 4 (4.3%)
No
Planned caesarean delivery (40) Yes
Vaginal delivery for both (68)
No
p value
Yes
No
Caesarean delivery for both (197) Yes
No
p value
70 (75.3%) 13 (32.5%) 27 (67.5%) 86 (92.5%) 6 (15%) 34 (85%) 93 (100%) 1 (2.5%) 39 (97.5%)
0.355 12 (17.6%) 56 (82.4%) 53 (26.9%) 144 (73.1%) 0.1432 0.183 5 (7.4%) 63 (92.6%) 17 (8.63%) 180 (91.4%) 40.99 0.126 0 (0%) 68 (100%) 5 (2.5%) 192 (97.5%) 0.3326
93 (100%) 89 (95.7%)
0.126 0.859
1 (2.5%) 2 (5%)
39 (97.5%) 38 (95%)
0 (0%) 4 (5.9%)
68 (100%) 64 (94.1%)
1 (0.5%) 7 (3.6%)
196 (99.5%) 40.99 190 (96.4%) 0.4806
PPH – Postpartum Hemorrhage.
world [24,25]. More units were delivering twins by caesarean delivery, although there was no strong evidence to support such a policy. This trend was also observed in our unit. Our vaginal twin delivery rate dropped from 70% in 1993 to as low as 10% in 2008 [16]. We had a substantial increase in the number of twin deliveries in 2009–2012 compared to 2006–2009. Reasons included a general increase in the number of total deliveries (18 221 versus 16 953 respectively) in our unit and also increased prevalence of artificial reproductive technique/IVF pregnancies. Artificial reproductive cases account for 45.8% (148/323) of all twin deliveries. 103/148 (69.6%) were performed in private hospitals, and another 22 (14.9%) were done in Mainland China. The rest were either performed in Hong Kong public hospitals (17/148 ! 11.5%) or other countries such as Taiwan or Thailand (6/148 ! 4%).
Compared with our previous cohort study, we noted a significant increase in vaginal twin delivery rate in these two 3-year periods, from 16.9% to 25.3%. Particularly for women who were suitable for vaginal delivery, the rate of attempting vaginal delivery increased tremendously from 47% to 69.9%. Despite the increase in attempt for vaginal delivery, the success rate was similar in these two periods (73.1% versus 74%). The rate of requiring caesarean delivery for 2nd twin did not increase significantly either (1% versus 1.5%) (p40.99). With proper counseling involving discussing pros and cons of vaginal delivery and caesarean delivery, a significant number of women who were suitable for vaginal twin delivery would be willing to attempt vaginal delivery. Caesarean delivery is not without risk. It leads to short-term complications (maternal morbidity and mortality) [26,27] and long-term complications
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(e.g. placenta praevia and accreta in future pregnancies) [28,29]. Vaginal delivery of 2nd twins requires skills in breech extraction, operative vaginal delivery, internal podalic version, and intrapartum ultrasound technique. Previous studies have shown that umbilical artery pH would be lower with longer intervals between the birth of the twins, both in monochorionic and dichorionic twins [30,31]. Presence of an experienced physician was one of the factors that could help to shorten the time-interval; for example, (s)he can perform a breech extraction by gripping the baby’s feet with intact membranes [32]. Mauldin and colleagues prospectively investigated 266 twin gestations, which supported that breech extraction in second non-vertex twins was the most cost-effective delivery management strategy, and these infants had significantly lower rates of pulmonary and neonatal infectious disease [33]. In our unit, internal podalic version would be performed for delivery of 2nd twin if baby was in oblique/transverse presentation, while breech extraction would be used for footling/flexed breech. Manual rotation would also be attempted for occipito-transverse/occipitoposterior (OT/OP) position if poor descent was noted for the 2nd twin even if it was in cephalic presentation [34]. Whenever we had a mother attempting vaginal delivery in labor ward, our labor ward consultant (WL) would discuss with the corresponding team, and be involved in decision making of suitability for vaginal twin delivery, assessment of progression, timing of deciding caesarean delivery in cases of failure to progress, and maneuvers used for 2nd twin delivery. Moreover, our unit tried time delivery of vaginal twins to ensure daytime delivery as much as possible. By starting the induction of labor for twins early in the morning, majority of them would be delivered in afternoon or early evening. Thus, more experienced personnel or even our labor ward consultant would be available in labor ward, supervising and teaching juniors how to perform various twin delivery maneuvers. To further enhance various vaginal twin delivery techniques of our trainees, we also arranged various team training workshops using manikins. Despite the increased vaginal twin delivery rate and the increased total twin delivery number in our unit, we did not find any significant differences between the neonatal/maternal morbidities of vaginal twin delivery and the neonatal/ maternal morbidities of elective CD for twins. From our data, apparently more 1st and 2nd twins in the attempted vaginal group required NICU admissions and neonatal resuscitation compared to that of the CD group. Many of them suffered from respiratory morbidities too. However, no statistical significance was identified after calculation. Moreover, all preterm deliveries 532 week belonged to the attempted vaginal group. Increased NICU admissions/neonatal resuscitation/respiratory morbidity was also anticipated observations of premature delivery. In terms of maternal morbidity, more postpartum hemorrhage was observed in caesarean group and planned caesarean group, but statistical significance was again not found. A similar trend for maternal/neonatal morbidity was also observed in our previous cohort study [15]. In conclusion, our data, together the recent publication of NEJM, supported our unit policy of promoting vaginal twin
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delivery. The key to successful vaginal twin delivery included practice and skill acquisition, appropriate training and supervision, presence of experienced staff at time of twin delivery and good use of intrapartum ultrasound [35]. Nevertheless, it was also important for continuous auditing in our unit to note for any increase in neonatal/maternal morbidities if our twin vaginal delivery rate is further increased. One limitation of our study was that there was a change in the computer coding policy of our hospital in 2009. When we went through the computer record during data collection, we found that more minor cases of morbidities, e.g. very minor cases of respiratory distress were coded in the computer system since 2009. Therefore, we did not make a direct statistical calculation comparing neonatal outcomes between data of both cohort studies. However, we had regular perinatal meetings and case reviews for adverse neonatal outcomes. No increased neonatal and maternal morbidities were observed for twins that were delivered in our unit throughout these years. Therefore, even without definite statistical calculation, we could say that there was no major worsening of neonatal and maternal outcomes despite our change of practice. Another limitation was that we did not evaluate the relationship between the neonatal outcomes of 2nd twin and the time interval between deliveries of both twins.
Declaration of interest The authors have no conflict of interest
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13. Vogel JP, Holloway E, Cuesta C, et al. Outcomes of non-vertex second twins, following vertex vaginal delivery of first twin: a secondary analysis of the WHO Global Survey on Maternal and Perinatal Health. BMC Pregnancy Childbirth 2014;14:55. 14. Barrett JF, Hannah ME, Hutton EK, et al. A randomized trial of planned cesarean or vaginal delivery for twin pregnancy. N Engl J Med 2013;369:1295–305. 15. Liu AL, Yung WK, Yeung HN, et al. Factors influencing the mode of delivery and associated pregnancy outcomes for twins: a retrospective cohort study in a public hospital. Hong Kong Med J 2012;18:99–107. 16. Tang HT, Liu AL, Yung WK, et al. Rebound Increase in vaginal delivery for twins in a regional obstetric unit in Hong Kong. IJGO 2014;126:96–7. 17. Yung WK, Liu AL, Lai SF, et al. Performance of a specialized twin pregnancy clinic in a public hospital. Hong Kong J Gynaecol Obstet Midwifery 2012;12:21–32. 18. Dodd JM, Deussen AR, Grivell RM, et al. Elective birth at 37 weeks’ gestation for women with an uncomplicated tiwn pregnancy. Cochrane Database Syst Rev 2014;2:CD003582. 19. NICE Guidelines. Multiple pregnancy: the management of twin and triplet pregnancies in the antenatal period. National Collaborating Centre for Women’s and Children’s Health (UK). London: RCOG Press; September 2011. 20. SOGC Clinical Practice Guidelines. Guidelines for vaginal birth after previous caesarean birth. No 155, February 2005. Int J Gynaecol Obstet 2005;89:319–31. 21. ACOG Practice Bulletin. Clinical management guidelines for obstetrician-gynaecologists. Vaginal birth after previous cesarean delivery. No 115, August 2010. Obstet Gynaecol 116(2, part 1). 22. RCOG Green Top Guidelines. Birth after previous caesarean birth. No 45. London: RCOG Press; February 2007. 23. Hannah ME, Hannah WJ, Hewson SA, et al. Planned caesarean section versus planned vaginal birth for breech presentation at term: a randomised multicentre trial: Term Breech Trial Collaborative Group. Lancet 2000;356:1375–83.
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24. Blanchette H. The rising caesarean delivery rate in America: what are the consequences? Obstet Gynaecol 2011;118:687–90. 25. Lee HC, Gould JB, Boscardin WJ, et al. Trends in caesarean delivery for twin births in the United States: 1995–2008. Obstet Gynaecol 2011;118:1095–101. 26. Souz JP, Gulmezoglu AM, Lumbiganon P, et al. Caesarean section without medical indications is associated with an increased risk of adverse short-term maternal outcomes: the 2004–2008 WHO global Survey on Maternal and Perinatal Health. BMC Med 2010;8:71. 27. Lumbiganon P, Laopaiboon M, Gulmezoglu AM, et al. Method of delivery and pregnancy outcomes in Asia: the WHO global survey on maternal and perinatal health 2007–08. Lancet 2010;375:490–9. 28. Daltveit AK, Tollanes MC, Pihlstrom H, Irgens LM. Cesarean delivery and subsequent pregnancies. Obstet Gynaecol 2008;111: 1327–34. 29. Yang Q, Wen SW, Oppenhemier L, et al. Association of caesarean delivery for first birth with placenta praevia and placental abruption in second pregnancy. BJOG 2007;114:609–13. 30. Quintana E, Burgos J, Equiguren N, et al. Influence of chorionicity in intra-partum management of twin deliveries. J Matern Fetal Neonatal Med 2013;26:407–11. 31. Vayssiere C, Benoist G, Blondel B, et al. Twin pregnancies: guidelines for clinical practice from the French College of Gynaecologists and Obstetricians (CNGOF). Eur J Obstet Gynaecol Reprod Biol 2011;156:12–17. 32. Arabin B, Kyvernitakis I. Vaginal delivery of the second nonvertex twin: avoiding a poor outcome when the presenting part is not engaged. Obstet Gynaecol 2011;118:950–4. 33. Mauldin JG, Newman RB, Mauldin PD. Cost-effective delivery management of the vertex and non-vertex twin gestation. Am J Obstet Gynecol 1998;179:864–9. 34. Sophia NEW, Andrew DL. Internal podalic version with breech extraction. The Obstetrician Gynaecologist 2011;13:7–14. 35. Chailillet N, Dumont A, Bujold E, et al. Quality of care, obstetrics risk management and mode of delivery in QueBEC (QUARISMA): a cluster-randomised trial. Am J Obstet Gynecol 2014;210:S2.
ORIGINAL ARTICLE
Twin pregnancy outcomes after increasing rate of vaginal twin delivery: retrospective cohort study in a Hong Kong regional obstetric unit
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Hiu Tung Tang, Ah Lai Liu, Sum Yee Chan, Chin Ho Lau, Wai Kuen Yung, Wai Lam Lau, and Wing Cheong Leung Department of Obstetrics and Gynaecology, Kwong Wah Hospital, Hong Kong
Abstract
Keywords
Objective: To determine any change in adverse neonatal/maternal outcomes after increasing the rate of vaginal twin delivery by comparing vaginal twin delivery and caesarean delivery with our previous cohort study. Methods: In a retrospective cohort study, all twins booked at a Hong Kong regional obstetrics unit were evaluated during a 3-year period from 1 April 2009 to 31 March 2012. Results: Out of the 269 sets of twins who eventually delivered in our unit, 68 (25.3%) of them were delivered vaginally, compared to 15.8% in our previous cohort study (p ¼ 0.02). For those who were suitable for vaginal delivery, significantly more women attempted vaginal delivery: 93/133 (69.9%) versus 47/100 (47%) (p ¼ 0.0005). The success rate for vaginal delivery and rate of requiring caesarean delivery for the 2nd twin were similar between these two periods. There were significantly more 2nd twins with cord blood pH57.2 when both twins were delivered by vaginal delivery. Otherwise, there was no significant difference between other neonatal/ maternal morbidities. Conclusion: With proper counseling, significantly more women who were suitable for vaginal twin delivery would opt to do so. There was no significant increase in neonatal/maternal morbidities despite the increased rate of vaginal twin delivery.
Caesarean delivery, maternal outcome, neonatal outcome, twins, vaginal delivery
Introduction With the increasing popularity of artificial reproductive technique, twin pregnancies occur more frequently now than in the past, and complicate approximately 2–3% of all births [1,2]. They are responsible for 10% of all perinatal mortality [3]. Previously several cohort studies have shown a reduced risk of adverse perinatal outcomes for both twins, or for the second twin, when twins at or near term were delivered by means of elective caesarean delivery (CD) [4–7]. However, there were also cohort studies, meta-analyses [8–13], and most importantly, a recent multi-centered large randomized controlled trial showing the opposite result [14]. Further, our unit also did a cohort study evaluating the mode of delivery and associated pregnancy outcomes of 197 sets of twins booked in our unit during 2006–2009. A high CD rate (82%) was observed in our unit. Except for higher frequency of sepsis and cord blood acidosis in the 2nd twin delivered vaginally, there were no significant differences in neonatal morbidity between the groups that attempted vaginal delivery or requested caesarean delivery [15].
Address for correspondence: Dr. Hiu Tung Tang, Department of Obstetrics and Gynaecology, N10, Kwong Wah Hospital, Waterloo Road, Hong Kong. Tel: +852 94961068/+852 35177983. Fax: +852 35177149. E-mail: [email protected]
History Received 1 November 2014 Revised 8 March 2015 Accepted 26 March 2015 Published online 20 April 2015
With the result of our cohort study, our unit from 2010 onwards re-promoted vaginal delivery for uncomplicated twin pregnancies if the first twin was in cephalic presentation. A standardized counseling approach for the mode of delivery was used in a designated twin clinic, along with the addition of a labor ward consultant. We subsequently observed a rebound increase in vaginal twin delivery rate since 2008, and it gradually climbed up to as high as 40% in 2012 (Figure 1). This observation has recently been published in the work by Tang et al. [16]. In view of this change in the trend of mode of twin delivery, we decided to have another cohort study subsequent to our previous cohort in order to study any difference in pregnancy outcomes after increasing the rate of vaginal twin delivery.
Materials and methods This was a retrospective cohort study, reviewing all twin pregnancies booked during the 3-year period from 1 April 2009 to 31 March 2012. In our unit, all booked twin pregnancies were recorded in a twin pregnancy clinic registry [17]. The pregnancies were then followed up in a specialized twin pregnancy clinic by a dedicated team of obstetricians and midwives. The team of obstetricians was specialized in maternal fetal medicine. Follow-up intervals were guided by the department protocol (available from the corresponding
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Figure 1. Vaginal delivery rate (%) of Twins in a regional Obstetric Unit in Hong Kong (1993–2012) [13].
author). Ultrasound examinations were performed on monochorionic twins every 2–3 weeks until 30 weeks of gestation, and at each visit after 30 weeks. For dichorionic twins, ultrasound examinations were performed monthly till 30 weeks, and at each visit after 30 weeks. When approaching term, the responsible obstetrician in the twin clinic discussed the mode of delivery with the mother and her partner (if available). In the absence of other contraindications to a trial of labor, vaginal twin delivery was considered an appropriate option for all dichorionic diamniotic(DCDA) and monochorionic diamniotic(MCDA) twin pregnancies if the first twin was in cephalic presentation, and no previous uterine scar. Induction of labor would be offered at 37–38-week gestation for MCDA as well as DCDA twins [18,19]. CD was recommended for all monochorionic monoamniotic(MCMA) twin pregnancies. We used the same method in data collection as in our previous cohort study [15]. Corresponding twin pregnancies were identified from the twin pregnancy clinic registry. Antenatal clinical notes, in-patients clinical notes and computer records of the women and their babies were reviewed in details. Moreover, women who were not booked but delivered in our unit during that period of time were also identified through our delivery registry in labor ward. For women who did not deliver in our unit, they would be contacted upon defaulting follow-up and their mode of delivery would be recorded in the clinical notes. Three investigators (HT, SY, CH) were involved in note review and data collection with agreement of definition used in data entry to avoid discrepancy during interpretation. A detailed data entry form (which was similar to that used in previous cohort study) was filled in for each set of twins. Maternal background information, including demographic data, medical history, obstetrical history, type of conception, antenatal and intrapartum complications, fetal presentations, mode of delivery, placental chorionicity, as well as neonatal and maternal outcomes were filled in for each set of twins. Neonatal outcomes included birth weight, gender, gestation at delivery, Apgar scores, cord blood pH, neonatal intensive care unit (NICU) admission,
birth trauma and neonatal morbidity. Neonatal morbidity was defined as respiratory morbidity, neurological morbidity, sepsis, or neonatal jaundice. Respiratory morbidity included respiratory distress syndrome, transient tachypnoea of the newborn, apnoea of prematurity, or pneumothorax. Neurological morbidity included intraventricular hemorrhage. Sepsis included those with clinical sepsis, cellulitis or necrotising enterocolitis. Maternal outcomes included blood loss, receipt of a blood transfusion, having compression sutures or hysterectomy to control postpartum hemorrhage. Statistical analysis was performed using the SPSS (Statistical Package for the Social Science Mac Version 22, Chicago, IL). Differences between categorical variables were analyzed using the Chi-square test. Differences between continuous variables were analyzed by independent samples t-test. p value 50.05 was considered statistically significant. Logistic regression was used to evaluate the relationship between education, history of vaginal delivery, type of conception, chorionicity and presentation of the 2nd twin, and the mother’s choice to attempt vaginal delivery or request caesarean delivery. Approval of the study was granted by the local research ethics committee (Ref no: KW/EX-14-101(75-16)). As this was a retrospective cohort study and the data were obtained from patients’ records, management of patient was not involved, and thus written informed consent was not needed in our study.
Result A total of 317 twins were booked in our unit during 1 April 2009 to 31 March 2012. Six non-booked cases were identified. Sixteen mothers defaulted our follow up and cannot be contacted. Eighteen of them delivered in private hospitals, all by CD. Twenty mothers delivered in other public hospitals: 4 via vaginal delivery and 16 via caesarean delivery. After excluding the 16 twin deliveries who defaulted from our study, we found that 72 sets of twins (23.5%) were delivered vaginally, 4 sets of twins involved vaginal delivery
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Figure 2. Flowchart of the number of twin pregnant mothers who were booked and finally delivered in our unit during 1 April 2009 to 31 March 2012.
of 1st twin and emergency CD of 2nd twin (1.3%). Twohundred thirty-one sets of twins (75.2%) were delivered by CD. Compared to our previous cohort study [15], we noted a substantial increase in the overall number of twins, and percentage of vaginal twin deliveries (16.9% versus 23.9%, p ¼ 0.0725). Two-hundred sixty-nine sets of twins were delivered in our unit during this period of time. Sixty-eight sets of twins (25.3%) were delivered by vaginal delivery, and four sets of twins (1.4%) involved vaginal delivery of first twin and emergency CD of 2nd twin. One hundred ninety-seven sets (73.2%) were delivered by CD for both twins. In our previous cohort study, only 15.8% of twins were delivered vaginally. A significant increase of vaginal delivery rate was identified (p ¼ 0.0245). Among those suitable for vaginal delivery, 93 out of 133 mothers (69.9%) attempted vaginal delivery in our current study, while only 47 out of 100 mothers (47%) attempted vaginal delivery in our previous cohort (p ¼ 0.0005). Success rate was found to be similar (73.1% versus 70.2%), and risk of requiring CD for 2nd twin did not significantly increase (4.3% versus 4.3%) (Figure 2). Reasons for choosing caesarean delivery were also evaluated. The most common indications for CD were
malpresentation of first twin (33.6%) and maternal request (20.3%). This group of maternal requests received CD, despite them having the following three conditions which were suitable for vaginal delivery: (1) DCDA or MCDA twin pregnancies, (2) the first twin was in cephalic presentation, and (3) there was no other obstetrics indication to have a CD. Excluding maternal request and malpresentation, other indications for CD included intrauterine growth retardation (14.7%), previous caesarean delivery (3.6%), no progress in labour (3.6%), pre-eclampsia (3%), and placental praevia (3%). Intrauterine growth retardation was defined as estimated fetal weight510th percentile of our local growth chart with or without abnormal Doppler. We realized that both guidelines published by ACOG and SOGC suggested that twin pregnancy was not a contraindication for attempting vaginal birth after previous caesarean (VBAC), while RCOG advised a cautious approach when considering VBAC for twins [20–22]. In our unit, previous CD is still an indication for repeat CD. However, in our previous cohort study, 32.7% of caesarean delivery was done purely for maternal request only (p ¼ 0.008). For those suitable for vaginal delivery, significantly more multiparous women (p ¼ 0.002), and women with second twin in cephalic presentation (p ¼ 0.005) were willing to attempt
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Table 1. Comparison of neonatal outcome between the pregnant mothers (considered suitable for vaginal delivery) who attempted vaginal delivery and planned caesarean delivery. Total number (133)
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Planned vaginal delivery (93)
Chorionicity of Twin (Yes – MCDA, No – DCDA) 1st twin: Mean birth weight (kg) 2nd twin: Mean birth weight (kg) 1st twin: cord blood pH 57.2 2nd twin cord blood pH 57.2 1st twin AS at 5 min: 4 7 2nd twin AS at 5 min: 4 7 1st twin NICU admission 2nd twin NICU admission Mean gestation age (week) Gestation at delivery 532 1st twin birth trauma 2nd twin birth trauma 1st twin neonatal resuscitation 2nd twin neonatal resuscitation 1st twin respiratory morbidity 1st twin sepsis 1st twin neonatal jaundice 1st twin neurological morbidity 2nd twin respiratory morbidity 2nd twin sepsis 2nd twin neonatal jaundice 2nd twin neurological morbidity
Planned caesarean delivery (40)
Yes
No
Yes
26 (27.7%)
58 (62.3%)
5 (12.5%)
2.34 (95% CI: 2.24–2.43) 2.39 (95% CI: 2.29–2.49) 7 (7.5%) 82 (88.2%) 13 (14.0%) 78 (83.9%) 1 (1%) 92 (99%) 2 (2.1%) 91 (97.9%) 0 (0%) 93 (100%) 1 (1%) 92 (99%) 8 (8.6%) 85 (91.4%) 9 (9.7%) 84 (90.3%) 35.9 (95% CI: 35.4–36.5) 7 (7.5%) 86 (92.5%) 4 (4.3%) 89 (95.7%) 2 (2.1%) 91 (97.9%) 6 (6.5%) 87 (93.5%) 7 (7.5%) 86 (88.2%) 20 (21.5%) 73 (78.5%) 8 (8.6%) 85 (91.4%) 17 (18.3%) 76 (82.7%) 5 (5.4%) 88 (94.6%) 20 (21.5%) 73 (78.5%) 10 (10.7%) 83 (89.2%) 13 (14.0%) 80 (86.0%) 3 (3.2%) 90 (96.8%)
No 32 (80%)
2.46 (95% CI: 2.34–2.58) 2.40 (95% CI 2.29–2.50) 3 (7.5%) 35 (87.5%) 2 (5%) 37 (92.5%) 0 (0%) 40 (100%) 0 (0%) 40 (100%) 0 (0%) 40 (100%) 0 (0%) 40 (100%) 0 (0%) 40 (100%) 1 (2.6%) 39 (93.7%) 36.6 (95% CI: 36.2–37.1) 0 (0%) 40 (100%) 0 (0%) 40 (100%) 0 (0%) 40 (100%) 0 (0%) 40 (100%) 1 (2.6%) 39 (93.7%) 5 (12.5%) 35 (87.5%) 5 (12.5%) 35 (87.5%) 11 (27.5%) 29 (72.5%) 0 (0%) 40 (100%) 4 (10%) 36 (90%) 4 (10%) 36 (90%) 4 (10%) 36 (90%) 1 (2.6%) 39 (93.7%)
p value 0.045 0.17 0.97 0.984 0.324 0.51 0.35 NA 0.51 0.056 0.15 0.163 0.075 0.183 0.35 0.1 0.264 0.223 0.488 0.232 0.135 0.114 0.897 0.529 40.99
MCDA – Monochorionic Diamniotic; DCDA – Dichorionic Diamniotic; AS – Apgar Score; NICU – Neonatal Intensive Care Unit.
vaginal delivery. Moreover, our multiparous women had a higher successful vaginal rate (88%) compared to nulliparous women (60%) (p ¼ 0.0023), while for the presentation of the 2nd twin, there was no significant difference in the success rate (76.1% versus 65.4%) (p ¼ 0.31). Although apparently more DCDA twins ended up with CD, after evaluating with multinomial logistic linear regression and controlling other factors such as history of vaginal delivery, presentation of 2nd twin, education level of mother and mode of conception, chorionicity was not significant. Neonatal outcomes and maternal outcomes were evaluated in twoways. Firstly, it was compared between those who attempted vaginal delivery and planned caesarean delivery for the pregnant mothers who were considered suitable for vaginal delivery. No significant difference between the AS, need for NICU admissions/neonatal resuscitation/respiratory/ sepsis/neurological morbidity was identified (Table 1). Secondly, neonatal outcomes were compared between those with vaginal delivery and caesarean delivery for both twins. Significantly more 2nd twins had cord blood pH 57.2 in vaginal twin deliveries. Otherwise, no significant difference between the need for NICU admissions/neonatal resuscitation/respiratory/sepsis/neurological morbidity was seen (Table 2). In our study, there were four pairs of twins who attempted vaginal delivery for 1st twin but required caesarean delivery for 2nd twin. Hand presentation of the 2nd twin was noted in one of the cases while there was another case where the second twin was noted to be in oblique breech position with
the cervix being clamped down to 5 cm. Amniotic membrane remained intact and syntocinon drip was not given in both cases. In the other 2 cases, 2nd twins were in cephalic presentation, uterine contractions subsided after delivery of 1st twins, amniotomy was not performed but a syntocinon drip was subsequently given; there was no strong uterine contraction in both cases despite syntocincon administration, and cervix remained 2 and 5 cm dilated, respectively, after 30 min. Emergency CD were arranged for these four cases. They all had good outcomes. None of the babies required NICU admissions or developed sepsis, respiratory, neurological or other neonatal complications except neonatal jaundice. The cord blood pHs of the 2nd twins were 7.13, 7.14, 7.26 and 7.28. Maternal outcome is outlined in Table 3. There was no statistically significant difference in the incidence of postpartum hemorrhage or blood transfusions. All patients requiring compression sutures were in the caesarean group, though the difference was not statistically significant. One patient required hysterectomy due to massive postpartum hemorrhage and she was in the caesarean group.
Discussion In 2000, Term Breech Trial [23] was published. The result indicated that planned caesarean delivery was associated with a better perinatal outcome. After this publication, rates of vaginal breech delivery decreased significantly, and rates of vaginal twin delivery also decreased throughout the
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Table 2. Comparison of neonatal outcome between the pregnant mothers with vaginal delivery and caesarean delivery for both twins. Total number (269) Vaginal delivery for both (68)
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Yes Chorionicity of Twin (Yes – MCDA, No – DCDA) 1st twin: Mean birth weight (kg) 2nd twin: Mean birth weight (kg) 1st twin: cord blood pH 57.2 2nd twin cord blood pH 57.2 1st twin AS at 5 min: 4 7 2nd twin AS at 5 min: 4 7 1st twin NICU admission 2nd twin NICU admission Mean gestation age (week) Gestation at delivery 532 1st twin birth trauma 2nd twin birth trauma 1st twin neonatal resuscitation 2nd twin neonatal resuscitation 1st twin respiratory morbidity 1st twin sepsis 1st twin neonatal jaundice 1st twin neurological morbidity 2nd twin respiratory morbidity 2nd twin sepsis 2nd twin neonatal jaundice 2nd twin neurological morbidity
Caesarean delivery for both (197) No
Yes
22 (32.3%) 38 (55.9%) 2.28 (95% CI: 2.16–2.38) 2.32 (95% CI: 2.20–2.43) 5 (7.4%) 60 (88.2%) 10 (14.7%) 56 (82.4%) 1 (1.5%) 67 (98.5%) 2 (2.9%) 66 (97.1%) 0 (0%) 68 (100%) 1 (1.5%) 67 (98.5%) 6 (9.7%) 62 (90.3%) 6 (9.7%) 62 (90.3%) 35.8 (95% CI 35.1–36.5) 6 (9.7%) 62 (90.3%) 2 (2.9%) 66 (97.1%) 2 (2.9%) 66 (97.1%) 4 (5.9%) 64 (94.1%) 6 (9.7%) 62 (90.3%) 15 (28.3%) 53 (71.7%) 5 (7.4%) 63 (92.6%) 13 (19.1%) 55 (80.9%) 4 (5.9%) 64 (94.1%) 16 (23.6%) 52 (76.4%) 7 (10.3%) 61 (89.7%) 11 (16.2%) 57 (83.8%) 2 (2.9%) 66 (97.1%)
No
p value
40 (16.2%) 141 (71.6%) 2.35 (95% CI: 2.28–2.42) 2.28 (95% CI: 2.21–2.36) 9 (4.6%) 185 (93.9%) 10 (5.1%) 185 (93.9%) 1 (0.5%) 196 (99.5%) 3 (1.5%) 194 (98.5%) 0 (0%) 194 (98.5%) 1 (0.5%) 196 (99.5%) 24 (10.7%) 173 (87.8%) 35 (17.8%) 162 (82.2%) 36 (95% CI 35.7–36.3) 11 (5.6%) 186 (94.4%) 4 (20.3%) 193 (79.7%) 0 (0%) 197 (100%) 13 (6.6%) 184 (93.4%) 16 (8.1%) 181 (91.9%) 47 (23.9%) 150 (76.1%) 24 (12.2%) 173 (87.8%) 43 (21.8%) 154 (78.2%) 9 (4.6%) 188 (95.4%) 52 (26.4%) 142 (72.1%) 28 (14.2%) 169 (84.7%) 39 (19.8%) 158 (80.2%) 12 (6.1%) 185 (93.9%)
0.04 0.28 0.62 0.3502 0.014 0.4481 0.6053 40.99 0.4481 0.5141 0.0836 0.507 0.7872 0.6484 0.0651 40.99 0.8037 0.8685 0.3685 0.7317 0.7453 0.6335 0.5341 0.5920 0.5295
MCDA – Monochorionic Diamniotic; DCDA – Dichorionic Diamniotic; AS – Apgar Score; NICU – Neonatal Intensive Care Unit.
Table 3. Comparison of maternal outcomes. Planned vaginal delivery (93) Maternal outcome
Yes
PPH 4500mL 23 (24.7%) PPH requiring extra drugs 7 (7.5%) PPH requiring 0 (0%) compression suture PPH requiring hysterectomy 0 (0%) Need for blood transfusion 4 (4.3%)
No
Planned caesarean delivery (40) Yes
Vaginal delivery for both (68)
No
p value
Yes
No
Caesarean delivery for both (197) Yes
No
p value
70 (75.3%) 13 (32.5%) 27 (67.5%) 86 (92.5%) 6 (15%) 34 (85%) 93 (100%) 1 (2.5%) 39 (97.5%)
0.355 12 (17.6%) 56 (82.4%) 53 (26.9%) 144 (73.1%) 0.1432 0.183 5 (7.4%) 63 (92.6%) 17 (8.63%) 180 (91.4%) 40.99 0.126 0 (0%) 68 (100%) 5 (2.5%) 192 (97.5%) 0.3326
93 (100%) 89 (95.7%)
0.126 0.859
1 (2.5%) 2 (5%)
39 (97.5%) 38 (95%)
0 (0%) 4 (5.9%)
68 (100%) 64 (94.1%)
1 (0.5%) 7 (3.6%)
196 (99.5%) 40.99 190 (96.4%) 0.4806
PPH – Postpartum Hemorrhage.
world [24,25]. More units were delivering twins by caesarean delivery, although there was no strong evidence to support such a policy. This trend was also observed in our unit. Our vaginal twin delivery rate dropped from 70% in 1993 to as low as 10% in 2008 [16]. We had a substantial increase in the number of twin deliveries in 2009–2012 compared to 2006–2009. Reasons included a general increase in the number of total deliveries (18 221 versus 16 953 respectively) in our unit and also increased prevalence of artificial reproductive technique/IVF pregnancies. Artificial reproductive cases account for 45.8% (148/323) of all twin deliveries. 103/148 (69.6%) were performed in private hospitals, and another 22 (14.9%) were done in Mainland China. The rest were either performed in Hong Kong public hospitals (17/148 ! 11.5%) or other countries such as Taiwan or Thailand (6/148 ! 4%).
Compared with our previous cohort study, we noted a significant increase in vaginal twin delivery rate in these two 3-year periods, from 16.9% to 25.3%. Particularly for women who were suitable for vaginal delivery, the rate of attempting vaginal delivery increased tremendously from 47% to 69.9%. Despite the increase in attempt for vaginal delivery, the success rate was similar in these two periods (73.1% versus 74%). The rate of requiring caesarean delivery for 2nd twin did not increase significantly either (1% versus 1.5%) (p40.99). With proper counseling involving discussing pros and cons of vaginal delivery and caesarean delivery, a significant number of women who were suitable for vaginal twin delivery would be willing to attempt vaginal delivery. Caesarean delivery is not without risk. It leads to short-term complications (maternal morbidity and mortality) [26,27] and long-term complications
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(e.g. placenta praevia and accreta in future pregnancies) [28,29]. Vaginal delivery of 2nd twins requires skills in breech extraction, operative vaginal delivery, internal podalic version, and intrapartum ultrasound technique. Previous studies have shown that umbilical artery pH would be lower with longer intervals between the birth of the twins, both in monochorionic and dichorionic twins [30,31]. Presence of an experienced physician was one of the factors that could help to shorten the time-interval; for example, (s)he can perform a breech extraction by gripping the baby’s feet with intact membranes [32]. Mauldin and colleagues prospectively investigated 266 twin gestations, which supported that breech extraction in second non-vertex twins was the most cost-effective delivery management strategy, and these infants had significantly lower rates of pulmonary and neonatal infectious disease [33]. In our unit, internal podalic version would be performed for delivery of 2nd twin if baby was in oblique/transverse presentation, while breech extraction would be used for footling/flexed breech. Manual rotation would also be attempted for occipito-transverse/occipitoposterior (OT/OP) position if poor descent was noted for the 2nd twin even if it was in cephalic presentation [34]. Whenever we had a mother attempting vaginal delivery in labor ward, our labor ward consultant (WL) would discuss with the corresponding team, and be involved in decision making of suitability for vaginal twin delivery, assessment of progression, timing of deciding caesarean delivery in cases of failure to progress, and maneuvers used for 2nd twin delivery. Moreover, our unit tried time delivery of vaginal twins to ensure daytime delivery as much as possible. By starting the induction of labor for twins early in the morning, majority of them would be delivered in afternoon or early evening. Thus, more experienced personnel or even our labor ward consultant would be available in labor ward, supervising and teaching juniors how to perform various twin delivery maneuvers. To further enhance various vaginal twin delivery techniques of our trainees, we also arranged various team training workshops using manikins. Despite the increased vaginal twin delivery rate and the increased total twin delivery number in our unit, we did not find any significant differences between the neonatal/maternal morbidities of vaginal twin delivery and the neonatal/ maternal morbidities of elective CD for twins. From our data, apparently more 1st and 2nd twins in the attempted vaginal group required NICU admissions and neonatal resuscitation compared to that of the CD group. Many of them suffered from respiratory morbidities too. However, no statistical significance was identified after calculation. Moreover, all preterm deliveries 532 week belonged to the attempted vaginal group. Increased NICU admissions/neonatal resuscitation/respiratory morbidity was also anticipated observations of premature delivery. In terms of maternal morbidity, more postpartum hemorrhage was observed in caesarean group and planned caesarean group, but statistical significance was again not found. A similar trend for maternal/neonatal morbidity was also observed in our previous cohort study [15]. In conclusion, our data, together the recent publication of NEJM, supported our unit policy of promoting vaginal twin
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delivery. The key to successful vaginal twin delivery included practice and skill acquisition, appropriate training and supervision, presence of experienced staff at time of twin delivery and good use of intrapartum ultrasound [35]. Nevertheless, it was also important for continuous auditing in our unit to note for any increase in neonatal/maternal morbidities if our twin vaginal delivery rate is further increased. One limitation of our study was that there was a change in the computer coding policy of our hospital in 2009. When we went through the computer record during data collection, we found that more minor cases of morbidities, e.g. very minor cases of respiratory distress were coded in the computer system since 2009. Therefore, we did not make a direct statistical calculation comparing neonatal outcomes between data of both cohort studies. However, we had regular perinatal meetings and case reviews for adverse neonatal outcomes. No increased neonatal and maternal morbidities were observed for twins that were delivered in our unit throughout these years. Therefore, even without definite statistical calculation, we could say that there was no major worsening of neonatal and maternal outcomes despite our change of practice. Another limitation was that we did not evaluate the relationship between the neonatal outcomes of 2nd twin and the time interval between deliveries of both twins.
Declaration of interest The authors have no conflict of interest
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DOI: 10.3109/14767058.2015.1035640
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