http://informahealthcare.com/jmf ISSN: 1476-7058 (print), 1476-4954 (electronic) J Matern Fetal Neonatal Med, 2015; 28(1): 23–25 ! 2015 Informa UK Ltd. DOI: 10.3109/14767058.2014.899576
ORIGINAL ARTICLE
Perinatal outcome of twin pregnancies according to chorionicity: an observational study from tertiary care hospital
J Matern Fetal Neonatal Med Downloaded from informahealthcare.com by Selcuk Universitesi on 02/10/15 For personal use only.
Shazia Masheer, Humaira Maheen, and Shama Munim Section of Fetal-Maternal Medicine and Neonatal Health, Aga Khan University Hospital, Karachi, Pakistan
Abstract
Keywords
Objective: To assess the perinatal outcome in twin pregnancies according to chorionicity. Methods: This was a retrospective cohort study of twin pregnancies from January 2001 to December 2012. Maternal and perinatal outcomes of monochorionic (MC) and dichorionic (DC) twins were compared by using chi-square and t-test. Perinatal complications were compared by adjusted odds ratio using logistic regression at 5% level of significance. Results: Among 391 twin pregnancies, 116 (29.6%) were MC and 275 (72.95%) were DC. In MC twins, the rate of miscarriage was three fold higher than DC (12.6% versus 4.4%; p-value50.000). Mean birth weight in DC was 218.4 g higher than the MC (p value50.000). Similarly, MC twins were 1.92 times [CI (1.02–3.62), p value ¼ 0.042] more likely to be delivered preterm. Likewise, neonatal intensive care admission for MC was 2.23 times [CI (1.08–4.06), p-value ¼ 0.03], congenital anomalies were 4.75 times [CI (1.22–18.4), p value ¼ 0.024]. Fetal growth restriction was 1.86 times more common in the MC twin pair [CI (1.07–3.21), p-value ¼ 0.026]. Conclusions: MC twins were more at risk for adverse outcomes than DC twins. Determining chorionicity at early pregnancy will help the Obstetricians to plan the care of these patients. This will help not only in managing twin pregnancies but also help in counseling according to the local perinatal outcome.
Congenital anomalies, dichorionic twins, monochorionic twins, morbidity, perinatal mortality
Introduction The incidence of twin pregnancies is increasing worldwide and now constitutes for 2–3% of all births in many centers [1–3]. This rise in the twin rate is attributed to the advanced maternal age and the use of assisted reproductive techniques [2]. Perinatal mortality (PNM) and morbidity of twins is three to seven times higher than singleton pregnancies [4]. Complications in twins are primarily due to the increased risk of preterm delivery and antenatal complications. Approximately 50% of twins are born preterm. The major complications associated with prematurity include respiratory distress syndrome, necrotizing enterocolitis, intraventricular hemorrhage, and sepsis [5]. Among the twins, Monochorionic (MC) twins are more at risk than compared to Dichorionic (DC) twins [5–7]. Complications include preterm delivery, growth discordance and death of one twin are the common complications. In addition, complications of monochorionicity accounts for
Address for correspondence: Shama Munim, Section Head and Associate Professor, Section of Fetal & Maternal Medicine and Neonatal Health, The Aga Khan University Hospital, Karachi, Pakistan. Tel: +92-2134864645, +92-213-4864606. Fax: +92-213-493-4294. E-mail: shama. [email protected]
History Received 14 September 2013 Revised 23 February 2014 Accepted 26 February 2014 Published online 9 April 2014
8–10% of cases [8]. This increase in perinatal morbidity and mortality has led to the opinion that monchorionic twins to be treated differently than DC twins. The aim of the present study is to evaluate perinatal outcome and mortality rate of twin pregnancies on the basis of chronicity in our set up. The results of this study would help in management and counseling of patients in our setup.
Methods It is a retrospective cohort study conducted at Aga Khan University Hospital, Karachi, Pakistan from January 2001 to December 2012. The Aga Khan University is a private sector tertiary referral center where more than 4500 deliveries are conducted annually. It is a private sector hospital in which one third of the pregnancies are at high risk. It receives patients from other hospitals of the city, nationally and internationally. In addition, it serves as a tertiary care center for the four secondary care Aga Khan hospitals Karimabad, Garden, Kharader and Hyderabad, which are located approximately 100 miles away from main campus. Our department is backed up with state-of-the-art Neonatal intensive care unit, which treats babies from 24 weeks onwards. The department also has the sub-speciality of maternal–fetal medicine. All the high-risk women attending the hospital are scanned in the
J Matern Fetal Neonatal Med Downloaded from informahealthcare.com by Selcuk Universitesi on 02/10/15 For personal use only.
24
S. Masheer et al.
J Matern Fetal Neonatal Med, 2015; 28(1): 23–25
fetal medicine unit. During 12-year study period there were 48 432 deliveries. Among these, there were 483 cases of multiple pregnancies. Of these 391 pregnant women were booked between 10 and 14 weeks of pregnancy and served as the study population. All cases of fetal aneuploidy, unknown chronicity were excluded from the analysis. In addition, only women where the outcome of pregnancy was known were included in the study. A prior ethical approval was obtained from the university ethics committee. The data were retrieved from the hospital medical records, labor room management system database and NICU medical records. Demographic variables include age, parity, miscarriage and pregnancy complications. Chorionicity was determined by ultrasound examination at 10–14 weeks of gestation by the presence or absence of lambda sign. Growth discordance is defined as the difference in birth weight of more than 20% discrepancy. In terms of neonatal outcome, birth weight, Apgar score and neonatal morbidities were also noted. Data were entered in a database file and analyzed by SPSS version 19.0 (software, Armonk, NY). Groups were compared by using chi-square for categorical variable and t-test for continuous variables. We obtained adjusted odd ratios for adverse neonatal outcome by using logistic regression analysis. p Value was considered significant at 0.05.
Results Of the total 391 pregnancies included in the analysis, there were 116 cases of MC pregnancy, and 275 cases of DC pregnancy. Mean maternal age and mode of delivery in both of the groups were not found to be significantly different in our study cohort. Median gestational age was 1 week longer in DC pregnancies. Mean birth weight in DC twins is 218.4 g higher than the MC twins (p value50.001). There were 12 cases (10.3%) of twin-to-twin syndrome (TTS) in MC twins (Table 1). Antenatal obstetric complications were not significantly different in the two groups (Table 2).However, the cases of preterm birth is substantially higher in the MC group [51.1% versus 27%, p value50.042]. (Table 2). Table 1. Demographic variable.
Variable Twin pregnancies Maternal age Gestation age at delivery* Parity Primiparous Multiparous Mode of delivery* SVD Caesarean Twin fetuses Birth weight Apgar Score 1 min 5 min Perinatal mortality Miscarriage IUD Neonatal deaths
MC twins n ¼ 232 (29.6)
DC Twins n ¼ 550 (70.3)
p value
27.8 ± 4.42 34.4 ± 3.57
28.5 ±4.86 35.5 ± 2.88
0.177 0.000
79 (84.9) 14 (15.1)
250 (90.9) 25 (9.1)
0.106
20 (23.0) 67 (77.0)
62 (23.5) 202 (76.5)
0.879
2016.4 ± 502.8
2234.8 ± 521.7
0.000
7.23 ± 1.36 8.51 ± 1.17
7.43 ± 1.15 8.74 ± 0.77
0.062 0.004
25 (12.6) 8 (3.4) 12 (6.0)
24 (4.4) 15 (2.7) 14 (2.5)
0.000 0.243 0.023
*Excludes miscarriages, and IUD.
The NICU admission is twice more likely in MC twins [OR 2.23, CI (1.08–4.06), p value ¼ 0.030]. Similarly, the odds of neonatal deaths were significantly higher in the in MC twin pregnancies than the DC pregnancy [OR 15.4, CI (1.47–162.1), p value ¼ 0.0223].
Discussion This is a large cohort study on twin pregnancies reporting the adverse perinatal outcome based on chorionicity. Although there are several studies conducted on the subject but data from this region are scarce. The dataset is derived from hospital-based records and is not a population-based study, it may not be a complete representation of the Pakistani population. However, it would still be useful for the Obstetricians managing twin pregnancies in our set up. The incidence of twins is on the rise. This is attributed to increasing use of Assisted Reproductive Techniques and advanced maternal age [9]. High incidence of twins is reported in the tertiary care setting [10]. The rate of twins in our setup was found to be 10 per 1000 pregnancies, this is slightly lower than reported [1]. This can be because this is a private sector tertiary care facility. We receive referrals from all over the city. When compared to the government sector hospital, selected and more severe cases are sent to us. In order to assess the influence of chorionicity on the adverse perinatal outcome, we included only those women who were sent to us for a scan between 10 and 14 weeks of pregnancy and the initial scan performed in our unit. We have excluded all women who were booked beyond this period. MC twins are more likely to develop pregnancy-related problems compared to DC twins [6,7]. Present study provides a comparison of these complications in relation to the chorionicity. Our results are consistent with that reported in the literature [6,7]. Congenital anomalies were four times more common in MC twins than in DC twins. Other investigators have reported similar findings [11]. In a UK-based study the RR of congenital anomalies among MC twins is twice than that of the DC [12]. A higher frequency of anomalies in a set up could be multifactorial. As the consanguinity also contributes to high number. Due to the retrospective nature of this study, we could not look into this aspect in detail. Preterm delivery is a well-known complication of multiple pregnancies. One in eight twin pregnancies are born before 32 weeks of gestation compared to 2 in 100 singletons [13]. The risk is significantly Table 2. Morbidity and mortality within study population. Variable
MC twins DC twins
Gestational diabetes* PPROM* Hypertension* FGR* Preterm birthy NICU admissiony Congenital anomaliesy Discordance in growthy Neonatal deathz
10 8 10 32 89 49 13 12 12
OR (95% CI)
(12.0) 44 (16.7) 1.38 (0.73–0.26) (9.8) 33 (12.5) 1.266 (0.63–2.51) (12.2) 53 (20.1) 1.86 (0.96–3.59) (19.4) 58 (11.0) 1.86 (1.07–3.21) (51.1) 142 (27.0) 1.92 (1.02–3.62) (28.8) 77 (14.6) 2.23 (1.08–4.06) (7.6) 11 (2.2) 4.75 (1.22–18.4) (16.9) 50 (20.1) 0.68 (0.33–1.39) (7.1) 11 (2.1) 15.4 (1.47–162.1)
*Adjusted for maternal age and parity. yAdjusted for maternal age, parity and birth weight. zAdjusted for maternal age and birth weight.
p value 0.311 0.501 0.063 0.026 0.042 0.03 0.024 0.29 0.022
Twin pregnancy outcome
J Matern Fetal Neonatal Med Downloaded from informahealthcare.com by Selcuk Universitesi on 02/10/15 For personal use only.
DOI: 10.3109/14767058.2014.899576
increased in MC twin pregnancy compared to DC. In our study population, the risk for preterm delivery was twice as common in the MC twins compared to DC pregnancies [OR 1.92]. Other studies have also observed similar findings. Manso et al. reported RR to be 1.69 [14]. The mean gestational age at delivery in MC twins was 34.36 weeks, while that in the DC pregnancies was 35.6 weeks. This could be attributed to the complications arising in the MC twins beyond this gestation. These findings are consistent to that reported in the literature [11]. In the last few years, we tend to deliver monchorionic twins by 36–37 weeks of gestation. This may have also reflected in the lower mean gestational age in the MC twins. It is well known that birth weight of newborn twins is lower than that of singleton pregnancy, with more than eight times higher risk of birth weight below 2500 g and 10 times higher risk of birth weight less than 1500 g [11]. The mean birth weight was 2149 which is similar to that reported in the literature [11]. According to the chorionicity, the mean birth weight was 2234.8 g in DC group compared to 2016.4 g in the MC group. In a Brazilian study, this was found to be 2165 g and 1827 g, respectively [11]. In a recently published Danish study, this was found to 2526.9 g in DC group and 2384.9 in the MC group [4,15]. Overall PNM of twins in our study was found to be 12.5%. However, MC twins have more than 1.5 times higher PNM in comparison to the DC twins [10]. Hanumaiah et al. [10] have found the PNM to be higher in their study population (152 per 1000). The PNM is directly related to the gestational age at delivery. The PNM was 13.2% in twins delivered before 30 weeks of gestation. In our cohort the PNM was found to be 0.7% in pregnancies delivered after 34 weeks of gestation. The NICU admission is twice of MC than in DC twins. Hacks et al. found odds of NICU admission to be 2.23. Both perinatal and neonatal death are twice more common in the MC twins compared to DC twins. Glinianaia et al. have found the RR of these complications to be 3.6 in their population [12]. In conclusion, this study highlights the importance of determining chorionicity at early pregnancy, as the results clearly demonstrates that fetal complications are more common in MC twins compared to DC twins. As the incidence of twins is on the rise, these findings will help the Obstetricians to plan the care of these patients. The limitation of this study was being its retrospective nature and being hospital based.
25
Declaration of interest The authors report no declarations of interest.
References 1. Ananth CV, Chauhan SP. Epidemiology of twinning in developed countries. Semin Perinatol 2012:36:156–61. 2. Biswas A, Su LL, Mattar C. Caesarean section for preterm birth and, breech presentation and twin pregnancies. Best Pract Res Clin Obstetr Gynaecol 2012:27:209–19. 3. Chauhan SP, Scardo JA, Hayes E, et al. Twins: prevalence, problems, and preterm births. Am J Obstetr Gynecol 2010:203: 305–15. 4. Hack KEA, Derks JB, Elias SG, et al. Increased perinatal mortality and morbidity in monochorionic versus dichorionic twin pregnancies: clinical implications of a large dutch cohort study. BJOG: Int J Obstet Gynaecol 2008:115:58–67. 5. Doss AE, Mancuso MS, Cliver SP, et al. Gestational age at delivery and perinatal outcomes of twin gestations. Am J Obstetr Gynecol 2012:207:410 e411–410 e416. 6. Lopriore E, Stroeken H, Sueters M, et al. Term perinatal mortality and morbidity in monochorionic and dichorionic twin pregnancies: a retrospective study. Acta Obstetricia et Gynecologica Scandinavica 2008:87:541–5. 7. Sherer DM. Adverse perinatal outcome of twin pregnancies according to chorionicity: review of the literature. Am J Perinatol 2001:18:23–37. 8. Acosta-Rojas R, Becker J, Munoz-Abellana B, et al. Twin chorionicity and the risk of adverse perinatal outcome. Int J Gynecol Obstetr 2007:96:98–102. 9. Lisonkova S, Joseph KS, Bell R, Glinianaia SV. Effect of advanced maternal age on perinatal outcomes in twins: the impact of chorionicity. Ann Epidemiol 2013:23:428–34. 10. Hanumaiah I, Shivanand DR, Visweshwaraiah KG, Hoolageri MS. Perinatal outcome of twin pregnancies at a tertiary care centre, south India. Int J Bio Med Res 2013:4:2683–5. 11. Assuncao RAd, Liao AW, Brizot MdL, et al. Perinatal outcome of twin pregnancies delivered in a teaching hospital. Rev Assoc Med Bras 2010:56:447–51. 12. Glinianaia SV, Obeysekera MA, Sturgiss S, Bell R. Stillbirth and neonatal mortality in monochorionic and dichorionic twins: a population-based study. Human Reproduction 2011:26: 2549–57. 13. Newman RB, Unal ER. Multiple gestations: timing of indicated late preterm and early-term births in uncomplicated dichorionic, monochorionic, and monoamniotic twins. Semin Perinatol 2011:118:277–85. 14. Manso P, Vaz A, Taborda A, Silva IS. Chorionicity and perinatal complications in twin pregnancy: a 10 years case series. Acta Madica Portuguesa 2011:24:695–8. 15. Oldenburg A, Rode L, Bødker B, et al. Influence of chorionicity on perinatal outcome in a large cohort of Danish twin pregnancies. Ultrasound Obstet Gynecol 2012:39:69–74.
ORIGINAL ARTICLE
Perinatal outcome of twin pregnancies according to chorionicity: an observational study from tertiary care hospital
J Matern Fetal Neonatal Med Downloaded from informahealthcare.com by Selcuk Universitesi on 02/10/15 For personal use only.
Shazia Masheer, Humaira Maheen, and Shama Munim Section of Fetal-Maternal Medicine and Neonatal Health, Aga Khan University Hospital, Karachi, Pakistan
Abstract
Keywords
Objective: To assess the perinatal outcome in twin pregnancies according to chorionicity. Methods: This was a retrospective cohort study of twin pregnancies from January 2001 to December 2012. Maternal and perinatal outcomes of monochorionic (MC) and dichorionic (DC) twins were compared by using chi-square and t-test. Perinatal complications were compared by adjusted odds ratio using logistic regression at 5% level of significance. Results: Among 391 twin pregnancies, 116 (29.6%) were MC and 275 (72.95%) were DC. In MC twins, the rate of miscarriage was three fold higher than DC (12.6% versus 4.4%; p-value50.000). Mean birth weight in DC was 218.4 g higher than the MC (p value50.000). Similarly, MC twins were 1.92 times [CI (1.02–3.62), p value ¼ 0.042] more likely to be delivered preterm. Likewise, neonatal intensive care admission for MC was 2.23 times [CI (1.08–4.06), p-value ¼ 0.03], congenital anomalies were 4.75 times [CI (1.22–18.4), p value ¼ 0.024]. Fetal growth restriction was 1.86 times more common in the MC twin pair [CI (1.07–3.21), p-value ¼ 0.026]. Conclusions: MC twins were more at risk for adverse outcomes than DC twins. Determining chorionicity at early pregnancy will help the Obstetricians to plan the care of these patients. This will help not only in managing twin pregnancies but also help in counseling according to the local perinatal outcome.
Congenital anomalies, dichorionic twins, monochorionic twins, morbidity, perinatal mortality
Introduction The incidence of twin pregnancies is increasing worldwide and now constitutes for 2–3% of all births in many centers [1–3]. This rise in the twin rate is attributed to the advanced maternal age and the use of assisted reproductive techniques [2]. Perinatal mortality (PNM) and morbidity of twins is three to seven times higher than singleton pregnancies [4]. Complications in twins are primarily due to the increased risk of preterm delivery and antenatal complications. Approximately 50% of twins are born preterm. The major complications associated with prematurity include respiratory distress syndrome, necrotizing enterocolitis, intraventricular hemorrhage, and sepsis [5]. Among the twins, Monochorionic (MC) twins are more at risk than compared to Dichorionic (DC) twins [5–7]. Complications include preterm delivery, growth discordance and death of one twin are the common complications. In addition, complications of monochorionicity accounts for
Address for correspondence: Shama Munim, Section Head and Associate Professor, Section of Fetal & Maternal Medicine and Neonatal Health, The Aga Khan University Hospital, Karachi, Pakistan. Tel: +92-2134864645, +92-213-4864606. Fax: +92-213-493-4294. E-mail: shama. [email protected]
History Received 14 September 2013 Revised 23 February 2014 Accepted 26 February 2014 Published online 9 April 2014
8–10% of cases [8]. This increase in perinatal morbidity and mortality has led to the opinion that monchorionic twins to be treated differently than DC twins. The aim of the present study is to evaluate perinatal outcome and mortality rate of twin pregnancies on the basis of chronicity in our set up. The results of this study would help in management and counseling of patients in our setup.
Methods It is a retrospective cohort study conducted at Aga Khan University Hospital, Karachi, Pakistan from January 2001 to December 2012. The Aga Khan University is a private sector tertiary referral center where more than 4500 deliveries are conducted annually. It is a private sector hospital in which one third of the pregnancies are at high risk. It receives patients from other hospitals of the city, nationally and internationally. In addition, it serves as a tertiary care center for the four secondary care Aga Khan hospitals Karimabad, Garden, Kharader and Hyderabad, which are located approximately 100 miles away from main campus. Our department is backed up with state-of-the-art Neonatal intensive care unit, which treats babies from 24 weeks onwards. The department also has the sub-speciality of maternal–fetal medicine. All the high-risk women attending the hospital are scanned in the
J Matern Fetal Neonatal Med Downloaded from informahealthcare.com by Selcuk Universitesi on 02/10/15 For personal use only.
24
S. Masheer et al.
J Matern Fetal Neonatal Med, 2015; 28(1): 23–25
fetal medicine unit. During 12-year study period there were 48 432 deliveries. Among these, there were 483 cases of multiple pregnancies. Of these 391 pregnant women were booked between 10 and 14 weeks of pregnancy and served as the study population. All cases of fetal aneuploidy, unknown chronicity were excluded from the analysis. In addition, only women where the outcome of pregnancy was known were included in the study. A prior ethical approval was obtained from the university ethics committee. The data were retrieved from the hospital medical records, labor room management system database and NICU medical records. Demographic variables include age, parity, miscarriage and pregnancy complications. Chorionicity was determined by ultrasound examination at 10–14 weeks of gestation by the presence or absence of lambda sign. Growth discordance is defined as the difference in birth weight of more than 20% discrepancy. In terms of neonatal outcome, birth weight, Apgar score and neonatal morbidities were also noted. Data were entered in a database file and analyzed by SPSS version 19.0 (software, Armonk, NY). Groups were compared by using chi-square for categorical variable and t-test for continuous variables. We obtained adjusted odd ratios for adverse neonatal outcome by using logistic regression analysis. p Value was considered significant at 0.05.
Results Of the total 391 pregnancies included in the analysis, there were 116 cases of MC pregnancy, and 275 cases of DC pregnancy. Mean maternal age and mode of delivery in both of the groups were not found to be significantly different in our study cohort. Median gestational age was 1 week longer in DC pregnancies. Mean birth weight in DC twins is 218.4 g higher than the MC twins (p value50.001). There were 12 cases (10.3%) of twin-to-twin syndrome (TTS) in MC twins (Table 1). Antenatal obstetric complications were not significantly different in the two groups (Table 2).However, the cases of preterm birth is substantially higher in the MC group [51.1% versus 27%, p value50.042]. (Table 2). Table 1. Demographic variable.
Variable Twin pregnancies Maternal age Gestation age at delivery* Parity Primiparous Multiparous Mode of delivery* SVD Caesarean Twin fetuses Birth weight Apgar Score 1 min 5 min Perinatal mortality Miscarriage IUD Neonatal deaths
MC twins n ¼ 232 (29.6)
DC Twins n ¼ 550 (70.3)
p value
27.8 ± 4.42 34.4 ± 3.57
28.5 ±4.86 35.5 ± 2.88
0.177 0.000
79 (84.9) 14 (15.1)
250 (90.9) 25 (9.1)
0.106
20 (23.0) 67 (77.0)
62 (23.5) 202 (76.5)
0.879
2016.4 ± 502.8
2234.8 ± 521.7
0.000
7.23 ± 1.36 8.51 ± 1.17
7.43 ± 1.15 8.74 ± 0.77
0.062 0.004
25 (12.6) 8 (3.4) 12 (6.0)
24 (4.4) 15 (2.7) 14 (2.5)
0.000 0.243 0.023
*Excludes miscarriages, and IUD.
The NICU admission is twice more likely in MC twins [OR 2.23, CI (1.08–4.06), p value ¼ 0.030]. Similarly, the odds of neonatal deaths were significantly higher in the in MC twin pregnancies than the DC pregnancy [OR 15.4, CI (1.47–162.1), p value ¼ 0.0223].
Discussion This is a large cohort study on twin pregnancies reporting the adverse perinatal outcome based on chorionicity. Although there are several studies conducted on the subject but data from this region are scarce. The dataset is derived from hospital-based records and is not a population-based study, it may not be a complete representation of the Pakistani population. However, it would still be useful for the Obstetricians managing twin pregnancies in our set up. The incidence of twins is on the rise. This is attributed to increasing use of Assisted Reproductive Techniques and advanced maternal age [9]. High incidence of twins is reported in the tertiary care setting [10]. The rate of twins in our setup was found to be 10 per 1000 pregnancies, this is slightly lower than reported [1]. This can be because this is a private sector tertiary care facility. We receive referrals from all over the city. When compared to the government sector hospital, selected and more severe cases are sent to us. In order to assess the influence of chorionicity on the adverse perinatal outcome, we included only those women who were sent to us for a scan between 10 and 14 weeks of pregnancy and the initial scan performed in our unit. We have excluded all women who were booked beyond this period. MC twins are more likely to develop pregnancy-related problems compared to DC twins [6,7]. Present study provides a comparison of these complications in relation to the chorionicity. Our results are consistent with that reported in the literature [6,7]. Congenital anomalies were four times more common in MC twins than in DC twins. Other investigators have reported similar findings [11]. In a UK-based study the RR of congenital anomalies among MC twins is twice than that of the DC [12]. A higher frequency of anomalies in a set up could be multifactorial. As the consanguinity also contributes to high number. Due to the retrospective nature of this study, we could not look into this aspect in detail. Preterm delivery is a well-known complication of multiple pregnancies. One in eight twin pregnancies are born before 32 weeks of gestation compared to 2 in 100 singletons [13]. The risk is significantly Table 2. Morbidity and mortality within study population. Variable
MC twins DC twins
Gestational diabetes* PPROM* Hypertension* FGR* Preterm birthy NICU admissiony Congenital anomaliesy Discordance in growthy Neonatal deathz
10 8 10 32 89 49 13 12 12
OR (95% CI)
(12.0) 44 (16.7) 1.38 (0.73–0.26) (9.8) 33 (12.5) 1.266 (0.63–2.51) (12.2) 53 (20.1) 1.86 (0.96–3.59) (19.4) 58 (11.0) 1.86 (1.07–3.21) (51.1) 142 (27.0) 1.92 (1.02–3.62) (28.8) 77 (14.6) 2.23 (1.08–4.06) (7.6) 11 (2.2) 4.75 (1.22–18.4) (16.9) 50 (20.1) 0.68 (0.33–1.39) (7.1) 11 (2.1) 15.4 (1.47–162.1)
*Adjusted for maternal age and parity. yAdjusted for maternal age, parity and birth weight. zAdjusted for maternal age and birth weight.
p value 0.311 0.501 0.063 0.026 0.042 0.03 0.024 0.29 0.022
Twin pregnancy outcome
J Matern Fetal Neonatal Med Downloaded from informahealthcare.com by Selcuk Universitesi on 02/10/15 For personal use only.
DOI: 10.3109/14767058.2014.899576
increased in MC twin pregnancy compared to DC. In our study population, the risk for preterm delivery was twice as common in the MC twins compared to DC pregnancies [OR 1.92]. Other studies have also observed similar findings. Manso et al. reported RR to be 1.69 [14]. The mean gestational age at delivery in MC twins was 34.36 weeks, while that in the DC pregnancies was 35.6 weeks. This could be attributed to the complications arising in the MC twins beyond this gestation. These findings are consistent to that reported in the literature [11]. In the last few years, we tend to deliver monchorionic twins by 36–37 weeks of gestation. This may have also reflected in the lower mean gestational age in the MC twins. It is well known that birth weight of newborn twins is lower than that of singleton pregnancy, with more than eight times higher risk of birth weight below 2500 g and 10 times higher risk of birth weight less than 1500 g [11]. The mean birth weight was 2149 which is similar to that reported in the literature [11]. According to the chorionicity, the mean birth weight was 2234.8 g in DC group compared to 2016.4 g in the MC group. In a Brazilian study, this was found to be 2165 g and 1827 g, respectively [11]. In a recently published Danish study, this was found to 2526.9 g in DC group and 2384.9 in the MC group [4,15]. Overall PNM of twins in our study was found to be 12.5%. However, MC twins have more than 1.5 times higher PNM in comparison to the DC twins [10]. Hanumaiah et al. [10] have found the PNM to be higher in their study population (152 per 1000). The PNM is directly related to the gestational age at delivery. The PNM was 13.2% in twins delivered before 30 weeks of gestation. In our cohort the PNM was found to be 0.7% in pregnancies delivered after 34 weeks of gestation. The NICU admission is twice of MC than in DC twins. Hacks et al. found odds of NICU admission to be 2.23. Both perinatal and neonatal death are twice more common in the MC twins compared to DC twins. Glinianaia et al. have found the RR of these complications to be 3.6 in their population [12]. In conclusion, this study highlights the importance of determining chorionicity at early pregnancy, as the results clearly demonstrates that fetal complications are more common in MC twins compared to DC twins. As the incidence of twins is on the rise, these findings will help the Obstetricians to plan the care of these patients. The limitation of this study was being its retrospective nature and being hospital based.
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Declaration of interest The authors report no declarations of interest.
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