http://informahealthcare.com/jmf ISSN: 1476-7058 (print), 1476-4954 (electronic) J Matern Fetal Neonatal Med, Early Online: 1–4 ! 2014 Informa UK Ltd. DOI: 10.3109/14767058.2014.934220
ORIGINAL ARTICLE
Postural balance in pregnancies complicated by hyperemesis gravidarum Bulent Cakmak1, Ahmet Inanir2, and Mehmet Can Nacar1 J Matern Fetal Neonatal Med Downloaded from informahealthcare.com by Nyu Medical Center on 10/16/14 For personal use only.
1
Department of Obstetrics and Gynaecology and 2Department of Physical Therapy and Rehabilitation, Gaziosmanpasa University School of Medicine, Tokat, Turkey Abstract
Keywords
Objective: To assess postural balance in females with pregnancies complicated by hyperemesis gravidarum (HG). Methods: In this observational study, postural balance during the first trimester was measured using the Biodex Balance System (BBS) in 41 pregnant females (20 females with pregnancies complicated by HG and 21 healthy controls). The overall stability index (OA), anterior-posterior stability index (APSI), medial-lateral stability index (MLSI) and fall risk test (FRT) scores were obtained from the mean scores of three trials on the BSS. The four measurements obtained from the BBS (OA, APSI, MLSI and FRT) were compared between healthy pregnant females and those with pregnancies complicated by HG (HG group). Results: The mean OA and APSI scores were significantly higher in the HG group compared to healthy pregnant controls (p50.01). There was no significant difference in the MLSI between the two groups (p40.05). The FRT scores of HG patients were higher than healthy pregnant females (p ¼ 0.001). Conclusions: Pregnant females with HG have poor postural stability/balance and high fall risk test scores. HG causes decreased postural equilibrium in the first trimester of pregnancy.
Fall, hyperemesis gravidarum, postural balance, pregnancy, stability
Introduction Morning sickness is characterised by nausea and vomiting in the first trimester of pregnancy and affects 70% of pregnant females [1,2]. One of the most common pregnancy-related complications is hyperemesis gravidarum (HG), a severe form of morning sickness. The prevalence of HG varies between 0.3 and 2% [2,3]. Dehydration, electrolyte imbalance, nutrient depletion and the loss of at least 5% body weight are some of the characteristic features of HG. HG typically begins in the first trimester of pregnancy and usually resolves by week 20, but can continue throughout pregnancy [4]. Females whose pregnancies are complicated by HG may also report depression, gastro-oesophageal reflux disease, anxiety, low blood pressure, restrictive diet, excessive saliva, haematemesis and dizziness [5]. Dizziness and vertigo are among the most common symptoms reported by pregnant females to primary care physicians, and vestibular abnormalities account for the majority of dizziness and vertigo cases [6]. There is a strong relationship between morning sickness (nausea and
Address for correspondence: Bulent Cakmak, Assistant Professor, M.D., Department of Obstetrics and Gynaecology, Gaziosmanpasa University School of Medicine, Kelardı Mahallesi, 60100, Tokat, Turkey. Tel: +90 356 2129500/1064. Fax: +90 356 2124221. E-mail: drbulentcakmak@ hotmail.com
History Received 24 March 2014 Revised 13 May 2014 Accepted 10 June 2014 Published online 27 June 2014
vomiting of pregnancy) and motion sickness, and both of these conditions are associated with the vestibular system [7]. In cases of dizziness due to vestibular dysfunction fall risk was increased 12-fold [8]. We therefore hypothesised that postural balance may be poor in pregnancies complicated with HG since it is related to morning sickness and dizziness via vestibular dysfunction. In addition, pregnancy even in the absence of complications has a negative effect on postural stability. Postural equilibrium decreases during pregnancy, particularly in the third trimester [9]. In contrast, Yu et al. investigated the relationship between morning sickness and body sway and found that standing body sway was reduced among females who experienced morning sickness compared to pregnant females who did not experience morning sickness during the first trimester [10]. The main objective of this study was to define dynamic postural stability during the first trimester in pregnant females with HG.
Method The study population consisted of 41 pregnant females between the ages of 18 and 37 years. All patients were in their first trimester of pregnancy and 20 had pregnancies complicated by HG (HG group), while the other 21 were healthy pregnant controls. The first trimester of pregnancy concludes at a gestational age of 12 weeks, and the females in
J Matern Fetal Neonatal Med Downloaded from informahealthcare.com by Nyu Medical Center on 10/16/14 For personal use only.
2
B. Cakmak et al.
this study were between 6 and 12 weeks. HG is described as nausea, vomiting, ketonuria, dehydration, electrolyte imbalance, nutrient depletion and the loss of at least 5% body weight. Control group consisted pregnant females who experienced neither morning sickness nor HG during present pregnancy. This study was approved by the faculty Ethics Committee, and written informed consent was obtained from all participants. Exclusion criteria included: multiple pregnancies, diabetes mellitus, hypertension, diagnosis of a high-risk pregnancy by an obstetrician, musculoskeletal or neurologic abnormalities and any other medical condition affecting postural stability (history of dizziness, falls or vestibular disorders prior to pregnancy). Data relating to age, number of pregnancies and births, height, weight, and body mass index (BMI) were obtained for all the participants. Postural balance was measured using the Biodex Balance System (BBS) (Biodex Medical Systems, Shirley, NY), a movable balance platform that provides up to 20 of surface tilt in a 360 range of motion. The platform is interfaced with computer software (Biodex, Version 3.1, Biodex Medical Systems) that enables the device to serve as an objective assessment of balance [11]. Total, anterior-posterior and medial-lateral balance indices were measured by the computer software. The system’s difficulty levels varied between 1 (most difficult) and 8 (the easiest). To reduce fall risk the platform was set and stabilised at level 8. Level 8 was used as the stable level for all subjects and all patients were tested at the same platform level. Data obtained from the BBS were used to calculate the overall stability index (OA), the anteriorposterior stability index (APSI), the medial-lateral stability index (MLSI) and the fall risk test (FRT) scores. The OA reveals general balance ability, the APSI is front-rear balance ability, while the MLSI refers to the ability to balance from side to side and FRT indicated the risk of falling. A high value in balance or fall indices indicates poor postural balance and increased fall risk [12]. The four measurements obtained from the BBS data were compared between the HG group and pregnant controls. All data were analysed using the PASW Statistics software, version 18.0 (SPSS, Chicago, IL). The Kolmogorov–Smirnov test was used to determine if continuous variables were normally distributed. Descriptive statistics included mean ± standard deviation and/or (min-max) for continuous variables. Significance differences between mean values were determined with Student’s t-test, and the Mann– Whitney U-test was used to evaluate the significance of differences between median values. p values 50.05 were considered to indicate statistical significance.
Results A total of 41 patients (20 in the HG group and 21 healthy controls) in the first trimester of pregnancy were evaluated in this observational study. Mean age, number of pregnancies, BMI and gestational weeks were 26.4 ± 4.8 years, 2.6 ± 1.1, 23.9 ± 2.3kg/m2 and 11 ± 1.0 weeks, respectively. Demographic characteristics were not significantly different between the groups (p40.05) (Table 1). The HG group had worse balance, because this group had higher postural stability (OA, APSI and MLSI) and FRT
J Matern Fetal Neonatal Med, Early Online: 1–4
Table 1. Demographic characteristics.
Age (year) Number of pregnancies Number of births Number of abortion Weight (kg) Height (cm) BMI (kg/m2)
Control (n ¼ 21)
HG (n ¼ 20)
p
25.0 ± 4.3 2.3 ± 1.0 [1–4] 0.9 ± 0.6 [0–2] 0.3 ± 0.6 [0–2] 63.4 ± 5.6 161.2 ± 0.5 24.4 ± 2.5
28.0 ± 5.0 3.0 ± 1.2 [1–5] 1.4 ± 0.9 [0–3] 0.4 ± 0.6 [0–2] 62.2 ± 5.1 163.1 ± 0.5 23.4 ± 1.8
0.054 0.064 0.061 0.690 0.469 0.295 0.143
Data are means ± SD [min-max]. HG: hyperemesis gravidarum; BMI: body mass index. Table 2. Postural stability and fall risk scores. Measure OA APSI MLSI FRT
Control (n ¼ 21)
HG (n ¼ 20)
p
0.58 ± 0.26 0.40 ± 0.22 0.32 ± 0.15 1.12 ± 0.55
0.96 ± 0.45 0.77 ± 0.40 0.43 ± 0.20 1.89 ± 0.87
0.003 0.001 0.061 0.002
OA: overall stability index; APSI: anterior-posterior stability index; MLSI: medial-lateral stability index; FRT: fall-risk test; HG: hyperemesis gravidarum. Data are means ± SD. The values of scores are given as degree.
scores (Table 2). Mean OA and APSI scores were significantly higher in the HG group compared to healthy controls (p50.01). There was no significant difference in the MLSI between the two groups (p40.05). The FRT scores of HG patients were higher than those of healthy pregnant females (p ¼ 0.001).
Discussion This study found that HG adversely affects postural balance during the first trimester. When evaluated using balance assessment system software, stability index scores of pregnant females with HG were higher than those of healthy pregnant females; fall risk tests scores were also higher in HG patients. These findings show that the first trimester, females with pregnancies complicated by HG have weaker dynamic postural balance and higher risk of falling when compared those of healthy pregnant females. Yu et al. published the first investigation of morning sickness and balance during the first trimester and found that morning sickness negatively affects postural stability during pregnancy [10]. The present study is the first to evaluate differences in postural stability between pregnant females with and without HG, and the results are similar to those of Yu et al. Postural stability decreases in HG complicated pregnancies. Yu et al. reported that dynamic sway was corrupted in both the AP and ML axes (p50.001). However, in the present study the stability of the AP axis was decreased in the HG group (p ¼ 0.001) and there were no statistically significant differences in the ML axis (p40.05). During pregnancy, several hormonal and anatomical changes occur in the female body. The increased risk of falling during pregnancy may be related to these anatomical and hormonal changes, such as increased ligamentous laxity and spinal lordosis [13], altered biomechanics [14] and an anterior shift in the location of the centre of mass [15].
Postural balance in hyperemesis gravidarum
J Matern Fetal Neonatal Med Downloaded from informahealthcare.com by Nyu Medical Center on 10/16/14 For personal use only.
DOI: 10.3109/14767058.2014.934220
One of the aetiopathologies of HG is hormonal changes during pregnancy; therefore, the poor postural stability of pregnant females with HG may be related to hormonal changes. Previous studies of postural stability during pregnancy report that standing postural, anterior-posterior and radial sway were increased in pregnant females when compared to non-pregnant females. While postural stability is stable during the first trimester, second and third trimester scores were significantly higher than controls [16,17]. In these studies, both the anterior-posterior sway and radial direction were deteriorated. In the present study, the OA and APSI were significantly deteriorated in pregnant females with HG. However, the MLSI was not significantly different between healthy pregnant females and those with HG. Thus the balance impairment observed in HG patients occurs through a different mechanism than the disequilibrium observed in previous studies during the third trimester. We know that there are many pathways by which a stimulus may evoke nausea and vomiting such as toxic material within the gut or in the blood, central nervous system stimuli and vestibular system abnormalities [18]. The different mechanisms of balance impairment observed with HG may be related to the vestibular system. Since hormonal changes occur in all pregnancies, but HG does not, it is possible that HG may be caused by vestibular system dysfunction. Pregnant females usually have a history of motion sickness and migraine, and they avoid from motion as a strategy for reducing nausea and vomiting during this period [19]. Morning sickness during pregnancy has similarities (such as nausea and vomiting) with motion sickness, and that the vestibular system may be involved in both conditions [7]. On the other hand, Goodwin et al. reported that pregnant females experienced HG had abnormalities in vestibuloocular reflex pathway [20]. Further investigation is needed to determine if the impaired postural stability observed in HG is related to vestibular system dysfunction. Falls during pregnancy are a common occurrence. In a retrospective study of 3900 pregnant females, Dunning et al. reported that 26.8% of females experienced a fall during pregnancy [21] and the incidence of hospitalisation due to a fall was 48.9 per 100 000 deliveries [22]. The majority of the falls that required hospitalisations occurred in the third trimester (79.3%), while 11.3% and 9.4% occurred in the second and first trimesters, respectively. The most common injuries due to falls were fractures, especially of the lower extremity, followed by contusions and sprains [22]. The cause of falls during pregnancy can be difficult to determine. The increased rate of weight gain during the third trimester may explain the decrease in postural stability during the same period [9]. Many studies have established an association between obesity, posture-kinetic deficits and fall risk [23,24], but the first trimester of pregnancy is not associated with weight gain, especially in pregnant females with HG, who lose weight during this period (at least 5% of their pre-pregnancy weight). In the present study the OA score, an indicator of general balance, and the FRT score were higher in the HG group compared to healthy pregnant controls, while there was no significant difference between the BMI of the two groups. Therefore, it is unlikely that weight loss affects the postural
3
balance of pregnant females with HG during the first trimester. Fall prevention during pregnancy prevents injuries. In a previous study, we evaluated the effect of maternity support belts on postural balance during pregnancy and found that the use of a maternity support garment improved balance and falling risk test scores during all stages of pregnancy, especially the third trimester [25]. Further investigation is needed to evaluate the benefit of fall prevention during the first trimester, specifically comparing the stability indices and fall risk scores of pregnant females with HG with and without fall prevention treatment. Regarding the present study, some limitations should be stated. First, we just assessed the postural balance and fall risk in pregnant females complicated by HG, but aetiopathogenesis was not evaluated. We found closer relationship between HG and poor balance, however, vestibular dysfunction could be investigated for interrelation among HG, balance and fall risk by using vestibular testing such as video nystagmography test and/or dizziness handicap inventory form. Many studies related with nausea and vomiting used the Rhodes index which provided information about subjectivity and frequency of these symptoms [10,26]. We did not use any index for definition of frequency of nausea and vomiting in this investigation. This index could be used in the present study but we used more objective findings such as the loss of body weight at least 5%, dehydration, electrolyte imbalance, nutrient depletion and ketonuria. Although the study population was sufficient for statistical analysing in this investigation, large population studies may provide high statistical power for the analyses of study outcomes. The present study is the first to investigate postural stability during the first trimester of pregnancies complicated by HG. Poor postural stability and increased fall risk were observed in females with HG. HG decreases postural equilibrium in the first trimester of pregnancy. Further research with a large study population is needed to evaluate the relationship between HG and postural balance.
Declaration of interest The authors report no declarations of interest.
References 1. Lacroix R, Eason E, Melzack R. Nausea and vomiting during pregnancy: a prospective study of its frequency, intensity, and patterns of change. Am J Obstet Gynecol 2000;182:931–7. 2. Einarson TR, Piwko C, Koren G. Quantifying the global rates of nausea and vomiting of pregnancy: a meta-analysis. J Popul Ther Clin Pharmacol 2013;20:171–83. 3. Eliakim R, Abulafia O, Sherer DM. Hyperemesis gravidarum: a current review. Am J Perinatol 2000;17:207–18. 4. American College of Obstetrics and Gynecology. ACOG (American College of Obstetrics and Gynecology) practice bulletin: Nausea and vomiting of pregnancy. Obstet Gynecol 2004;103: 803–14. 5. Mullin PM, Ching CY, Shoenberg F, et al. Risk factors, treatments, and outcomes associated with prolonged hyperemesis gravidarum. J Matern Fetal Neonatal Med 2012;25:632–6. 6. Sloane PD. Dizziness in primary care: results from the National Ambulatory Medical Care Survey. J Fam Pract 1989;29:33–8. 7. Black FO. Maternal susceptibility to nausea and vomiting of pregnancy: is the vestibular system involved? Am J Obstet Gynecol 2002;186:204–9.
J Matern Fetal Neonatal Med Downloaded from informahealthcare.com by Nyu Medical Center on 10/16/14 For personal use only.
4
B. Cakmak et al.
8. Agrawal Y, Carey JP, Della Santina CC, et al. Disorders of balance and vestibular function in US adults. Arch Intern Med 2009;169: 938–44. 9. McCrory JL, Chambers AJ, Daftary A, Redfern MS. Dynamic postural stability during advancing pregnancy. J Biomech 2010;43: 2434–9. 10. Yu Y, Chung HC, Hemingway L, Stoffregen TA. Standing body sway in females with and without morning sickness in pregnancy. Gait Posture 2013;37:103–7. 11. Cachupe WC, Shifflett B, Kahanov L, Wughalter EH. Reliability of Biodex Balance System measures. Meas Phys Educ Exerc Sci 2001; 5:97–108. 12. Testerman C, Vander Griend R. Evaluation of ankle instability using the Biodex Stability System. Foot Ankle Int 1999;20:317–21. 13. Calguneri M, Bird H, Wright V. Changes in joint laxity occurring during pregnancy. Ann Rheum Dis 1982;41:126–8. 14. Gilleard W, Brown J. Structure and function of the abdominal muscles in primigravid subjects during pregnancy and the immediate postbirth period. Phys Ther 1996;76:750–62. 15. Whitcome KK, Shapiro LJ, Lieberman DE. Fetal load and the evolution of lumbar lordosis in bipedal hominins. Nature 2007;450: 1075–8. 16. Butler EE, Colon I, Druzin ML, Rose J. Postural equilibrium during pregnancy: decreased stability with an increased reliance on visual cues. Am J Obstet Gynecol 2006;195:1104–8. 17. Jang J, Hsiao KT, Hsiao-Wecksler ET. Balance (perceived and actual) and preferred stance width during pregnancy. Clin Biomech (Bristol, Avon) 2008;23:468–76.
J Matern Fetal Neonatal Med, Early Online: 1–4
18. Heinrichs L. Linking olfaction with nausea and vomiting of pregnancy, hyperemesis gravidarum and migraine headache. Am J Obstet Gynecol 2002;186:S215–19. 19. O’Brien B, Naber S. Nausea and vomiting during pregnancy: effects on the quality of women’s lives. Birth 1992; 19:138–43. 20. Goodwin TM, Nwankwo OA, Davis-O’Leary L, et al. The first demonstration that a subset of women with hyperemesis gravidarum has abnormalities in the vestibuloocular reflex pathway. Am J Obstet Gynecol 2008;199:417.e1–417.e9. 21. Dunning K, LeMasters G, Levin L, et al. Falls in workers during pregnancy: risk factors, job hazards, and high risk occupations. Am J Ind Med 2003;44:664–72. 22. Schiff MA. Pregnancy outcomes following hospitalization for a fall in Washington State from 1987 to 2004. BJOG 2008;115: 1648–54. 23. Hue O, Simoneau M, Marcotte J, et al. Body weight is a strong predictor of postural stability. Gait Posture 2007;26:32–8. 24. Corbeil P, Simoneau M, Rancourt D, et al. Increased risk for falling associated with obesity: mathematical modeling of postural control. IEEE Transac Neural Systems Rehab Eng 2001;9:126–36. 25. Cakmak B, Inanir A, Nacar MC, Filiz B. The effect of maternity support belts on postural balance in pregnancy. PM R. 2014 Jan 8. Pii: S1934-1482(13)1234-3. (doi.org/10.1016/j.pmrj.2013.12.012). [Epub ahead of print]. 26. Genc A, Can G, Aydiner A. The efficiency of the acupressure in prevention of the chemotherapy-induced nausea and vomiting. Support Care Cancer 2013;21:253–61.
ORIGINAL ARTICLE
Postural balance in pregnancies complicated by hyperemesis gravidarum Bulent Cakmak1, Ahmet Inanir2, and Mehmet Can Nacar1 J Matern Fetal Neonatal Med Downloaded from informahealthcare.com by Nyu Medical Center on 10/16/14 For personal use only.
1
Department of Obstetrics and Gynaecology and 2Department of Physical Therapy and Rehabilitation, Gaziosmanpasa University School of Medicine, Tokat, Turkey Abstract
Keywords
Objective: To assess postural balance in females with pregnancies complicated by hyperemesis gravidarum (HG). Methods: In this observational study, postural balance during the first trimester was measured using the Biodex Balance System (BBS) in 41 pregnant females (20 females with pregnancies complicated by HG and 21 healthy controls). The overall stability index (OA), anterior-posterior stability index (APSI), medial-lateral stability index (MLSI) and fall risk test (FRT) scores were obtained from the mean scores of three trials on the BSS. The four measurements obtained from the BBS (OA, APSI, MLSI and FRT) were compared between healthy pregnant females and those with pregnancies complicated by HG (HG group). Results: The mean OA and APSI scores were significantly higher in the HG group compared to healthy pregnant controls (p50.01). There was no significant difference in the MLSI between the two groups (p40.05). The FRT scores of HG patients were higher than healthy pregnant females (p ¼ 0.001). Conclusions: Pregnant females with HG have poor postural stability/balance and high fall risk test scores. HG causes decreased postural equilibrium in the first trimester of pregnancy.
Fall, hyperemesis gravidarum, postural balance, pregnancy, stability
Introduction Morning sickness is characterised by nausea and vomiting in the first trimester of pregnancy and affects 70% of pregnant females [1,2]. One of the most common pregnancy-related complications is hyperemesis gravidarum (HG), a severe form of morning sickness. The prevalence of HG varies between 0.3 and 2% [2,3]. Dehydration, electrolyte imbalance, nutrient depletion and the loss of at least 5% body weight are some of the characteristic features of HG. HG typically begins in the first trimester of pregnancy and usually resolves by week 20, but can continue throughout pregnancy [4]. Females whose pregnancies are complicated by HG may also report depression, gastro-oesophageal reflux disease, anxiety, low blood pressure, restrictive diet, excessive saliva, haematemesis and dizziness [5]. Dizziness and vertigo are among the most common symptoms reported by pregnant females to primary care physicians, and vestibular abnormalities account for the majority of dizziness and vertigo cases [6]. There is a strong relationship between morning sickness (nausea and
Address for correspondence: Bulent Cakmak, Assistant Professor, M.D., Department of Obstetrics and Gynaecology, Gaziosmanpasa University School of Medicine, Kelardı Mahallesi, 60100, Tokat, Turkey. Tel: +90 356 2129500/1064. Fax: +90 356 2124221. E-mail: drbulentcakmak@ hotmail.com
History Received 24 March 2014 Revised 13 May 2014 Accepted 10 June 2014 Published online 27 June 2014
vomiting of pregnancy) and motion sickness, and both of these conditions are associated with the vestibular system [7]. In cases of dizziness due to vestibular dysfunction fall risk was increased 12-fold [8]. We therefore hypothesised that postural balance may be poor in pregnancies complicated with HG since it is related to morning sickness and dizziness via vestibular dysfunction. In addition, pregnancy even in the absence of complications has a negative effect on postural stability. Postural equilibrium decreases during pregnancy, particularly in the third trimester [9]. In contrast, Yu et al. investigated the relationship between morning sickness and body sway and found that standing body sway was reduced among females who experienced morning sickness compared to pregnant females who did not experience morning sickness during the first trimester [10]. The main objective of this study was to define dynamic postural stability during the first trimester in pregnant females with HG.
Method The study population consisted of 41 pregnant females between the ages of 18 and 37 years. All patients were in their first trimester of pregnancy and 20 had pregnancies complicated by HG (HG group), while the other 21 were healthy pregnant controls. The first trimester of pregnancy concludes at a gestational age of 12 weeks, and the females in
J Matern Fetal Neonatal Med Downloaded from informahealthcare.com by Nyu Medical Center on 10/16/14 For personal use only.
2
B. Cakmak et al.
this study were between 6 and 12 weeks. HG is described as nausea, vomiting, ketonuria, dehydration, electrolyte imbalance, nutrient depletion and the loss of at least 5% body weight. Control group consisted pregnant females who experienced neither morning sickness nor HG during present pregnancy. This study was approved by the faculty Ethics Committee, and written informed consent was obtained from all participants. Exclusion criteria included: multiple pregnancies, diabetes mellitus, hypertension, diagnosis of a high-risk pregnancy by an obstetrician, musculoskeletal or neurologic abnormalities and any other medical condition affecting postural stability (history of dizziness, falls or vestibular disorders prior to pregnancy). Data relating to age, number of pregnancies and births, height, weight, and body mass index (BMI) were obtained for all the participants. Postural balance was measured using the Biodex Balance System (BBS) (Biodex Medical Systems, Shirley, NY), a movable balance platform that provides up to 20 of surface tilt in a 360 range of motion. The platform is interfaced with computer software (Biodex, Version 3.1, Biodex Medical Systems) that enables the device to serve as an objective assessment of balance [11]. Total, anterior-posterior and medial-lateral balance indices were measured by the computer software. The system’s difficulty levels varied between 1 (most difficult) and 8 (the easiest). To reduce fall risk the platform was set and stabilised at level 8. Level 8 was used as the stable level for all subjects and all patients were tested at the same platform level. Data obtained from the BBS were used to calculate the overall stability index (OA), the anteriorposterior stability index (APSI), the medial-lateral stability index (MLSI) and the fall risk test (FRT) scores. The OA reveals general balance ability, the APSI is front-rear balance ability, while the MLSI refers to the ability to balance from side to side and FRT indicated the risk of falling. A high value in balance or fall indices indicates poor postural balance and increased fall risk [12]. The four measurements obtained from the BBS data were compared between the HG group and pregnant controls. All data were analysed using the PASW Statistics software, version 18.0 (SPSS, Chicago, IL). The Kolmogorov–Smirnov test was used to determine if continuous variables were normally distributed. Descriptive statistics included mean ± standard deviation and/or (min-max) for continuous variables. Significance differences between mean values were determined with Student’s t-test, and the Mann– Whitney U-test was used to evaluate the significance of differences between median values. p values 50.05 were considered to indicate statistical significance.
Results A total of 41 patients (20 in the HG group and 21 healthy controls) in the first trimester of pregnancy were evaluated in this observational study. Mean age, number of pregnancies, BMI and gestational weeks were 26.4 ± 4.8 years, 2.6 ± 1.1, 23.9 ± 2.3kg/m2 and 11 ± 1.0 weeks, respectively. Demographic characteristics were not significantly different between the groups (p40.05) (Table 1). The HG group had worse balance, because this group had higher postural stability (OA, APSI and MLSI) and FRT
J Matern Fetal Neonatal Med, Early Online: 1–4
Table 1. Demographic characteristics.
Age (year) Number of pregnancies Number of births Number of abortion Weight (kg) Height (cm) BMI (kg/m2)
Control (n ¼ 21)
HG (n ¼ 20)
p
25.0 ± 4.3 2.3 ± 1.0 [1–4] 0.9 ± 0.6 [0–2] 0.3 ± 0.6 [0–2] 63.4 ± 5.6 161.2 ± 0.5 24.4 ± 2.5
28.0 ± 5.0 3.0 ± 1.2 [1–5] 1.4 ± 0.9 [0–3] 0.4 ± 0.6 [0–2] 62.2 ± 5.1 163.1 ± 0.5 23.4 ± 1.8
0.054 0.064 0.061 0.690 0.469 0.295 0.143
Data are means ± SD [min-max]. HG: hyperemesis gravidarum; BMI: body mass index. Table 2. Postural stability and fall risk scores. Measure OA APSI MLSI FRT
Control (n ¼ 21)
HG (n ¼ 20)
p
0.58 ± 0.26 0.40 ± 0.22 0.32 ± 0.15 1.12 ± 0.55
0.96 ± 0.45 0.77 ± 0.40 0.43 ± 0.20 1.89 ± 0.87
0.003 0.001 0.061 0.002
OA: overall stability index; APSI: anterior-posterior stability index; MLSI: medial-lateral stability index; FRT: fall-risk test; HG: hyperemesis gravidarum. Data are means ± SD. The values of scores are given as degree.
scores (Table 2). Mean OA and APSI scores were significantly higher in the HG group compared to healthy controls (p50.01). There was no significant difference in the MLSI between the two groups (p40.05). The FRT scores of HG patients were higher than those of healthy pregnant females (p ¼ 0.001).
Discussion This study found that HG adversely affects postural balance during the first trimester. When evaluated using balance assessment system software, stability index scores of pregnant females with HG were higher than those of healthy pregnant females; fall risk tests scores were also higher in HG patients. These findings show that the first trimester, females with pregnancies complicated by HG have weaker dynamic postural balance and higher risk of falling when compared those of healthy pregnant females. Yu et al. published the first investigation of morning sickness and balance during the first trimester and found that morning sickness negatively affects postural stability during pregnancy [10]. The present study is the first to evaluate differences in postural stability between pregnant females with and without HG, and the results are similar to those of Yu et al. Postural stability decreases in HG complicated pregnancies. Yu et al. reported that dynamic sway was corrupted in both the AP and ML axes (p50.001). However, in the present study the stability of the AP axis was decreased in the HG group (p ¼ 0.001) and there were no statistically significant differences in the ML axis (p40.05). During pregnancy, several hormonal and anatomical changes occur in the female body. The increased risk of falling during pregnancy may be related to these anatomical and hormonal changes, such as increased ligamentous laxity and spinal lordosis [13], altered biomechanics [14] and an anterior shift in the location of the centre of mass [15].
Postural balance in hyperemesis gravidarum
J Matern Fetal Neonatal Med Downloaded from informahealthcare.com by Nyu Medical Center on 10/16/14 For personal use only.
DOI: 10.3109/14767058.2014.934220
One of the aetiopathologies of HG is hormonal changes during pregnancy; therefore, the poor postural stability of pregnant females with HG may be related to hormonal changes. Previous studies of postural stability during pregnancy report that standing postural, anterior-posterior and radial sway were increased in pregnant females when compared to non-pregnant females. While postural stability is stable during the first trimester, second and third trimester scores were significantly higher than controls [16,17]. In these studies, both the anterior-posterior sway and radial direction were deteriorated. In the present study, the OA and APSI were significantly deteriorated in pregnant females with HG. However, the MLSI was not significantly different between healthy pregnant females and those with HG. Thus the balance impairment observed in HG patients occurs through a different mechanism than the disequilibrium observed in previous studies during the third trimester. We know that there are many pathways by which a stimulus may evoke nausea and vomiting such as toxic material within the gut or in the blood, central nervous system stimuli and vestibular system abnormalities [18]. The different mechanisms of balance impairment observed with HG may be related to the vestibular system. Since hormonal changes occur in all pregnancies, but HG does not, it is possible that HG may be caused by vestibular system dysfunction. Pregnant females usually have a history of motion sickness and migraine, and they avoid from motion as a strategy for reducing nausea and vomiting during this period [19]. Morning sickness during pregnancy has similarities (such as nausea and vomiting) with motion sickness, and that the vestibular system may be involved in both conditions [7]. On the other hand, Goodwin et al. reported that pregnant females experienced HG had abnormalities in vestibuloocular reflex pathway [20]. Further investigation is needed to determine if the impaired postural stability observed in HG is related to vestibular system dysfunction. Falls during pregnancy are a common occurrence. In a retrospective study of 3900 pregnant females, Dunning et al. reported that 26.8% of females experienced a fall during pregnancy [21] and the incidence of hospitalisation due to a fall was 48.9 per 100 000 deliveries [22]. The majority of the falls that required hospitalisations occurred in the third trimester (79.3%), while 11.3% and 9.4% occurred in the second and first trimesters, respectively. The most common injuries due to falls were fractures, especially of the lower extremity, followed by contusions and sprains [22]. The cause of falls during pregnancy can be difficult to determine. The increased rate of weight gain during the third trimester may explain the decrease in postural stability during the same period [9]. Many studies have established an association between obesity, posture-kinetic deficits and fall risk [23,24], but the first trimester of pregnancy is not associated with weight gain, especially in pregnant females with HG, who lose weight during this period (at least 5% of their pre-pregnancy weight). In the present study the OA score, an indicator of general balance, and the FRT score were higher in the HG group compared to healthy pregnant controls, while there was no significant difference between the BMI of the two groups. Therefore, it is unlikely that weight loss affects the postural
3
balance of pregnant females with HG during the first trimester. Fall prevention during pregnancy prevents injuries. In a previous study, we evaluated the effect of maternity support belts on postural balance during pregnancy and found that the use of a maternity support garment improved balance and falling risk test scores during all stages of pregnancy, especially the third trimester [25]. Further investigation is needed to evaluate the benefit of fall prevention during the first trimester, specifically comparing the stability indices and fall risk scores of pregnant females with HG with and without fall prevention treatment. Regarding the present study, some limitations should be stated. First, we just assessed the postural balance and fall risk in pregnant females complicated by HG, but aetiopathogenesis was not evaluated. We found closer relationship between HG and poor balance, however, vestibular dysfunction could be investigated for interrelation among HG, balance and fall risk by using vestibular testing such as video nystagmography test and/or dizziness handicap inventory form. Many studies related with nausea and vomiting used the Rhodes index which provided information about subjectivity and frequency of these symptoms [10,26]. We did not use any index for definition of frequency of nausea and vomiting in this investigation. This index could be used in the present study but we used more objective findings such as the loss of body weight at least 5%, dehydration, electrolyte imbalance, nutrient depletion and ketonuria. Although the study population was sufficient for statistical analysing in this investigation, large population studies may provide high statistical power for the analyses of study outcomes. The present study is the first to investigate postural stability during the first trimester of pregnancies complicated by HG. Poor postural stability and increased fall risk were observed in females with HG. HG decreases postural equilibrium in the first trimester of pregnancy. Further research with a large study population is needed to evaluate the relationship between HG and postural balance.
Declaration of interest The authors report no declarations of interest.
References 1. Lacroix R, Eason E, Melzack R. Nausea and vomiting during pregnancy: a prospective study of its frequency, intensity, and patterns of change. Am J Obstet Gynecol 2000;182:931–7. 2. Einarson TR, Piwko C, Koren G. Quantifying the global rates of nausea and vomiting of pregnancy: a meta-analysis. J Popul Ther Clin Pharmacol 2013;20:171–83. 3. Eliakim R, Abulafia O, Sherer DM. Hyperemesis gravidarum: a current review. Am J Perinatol 2000;17:207–18. 4. American College of Obstetrics and Gynecology. ACOG (American College of Obstetrics and Gynecology) practice bulletin: Nausea and vomiting of pregnancy. Obstet Gynecol 2004;103: 803–14. 5. Mullin PM, Ching CY, Shoenberg F, et al. Risk factors, treatments, and outcomes associated with prolonged hyperemesis gravidarum. J Matern Fetal Neonatal Med 2012;25:632–6. 6. Sloane PD. Dizziness in primary care: results from the National Ambulatory Medical Care Survey. J Fam Pract 1989;29:33–8. 7. Black FO. Maternal susceptibility to nausea and vomiting of pregnancy: is the vestibular system involved? Am J Obstet Gynecol 2002;186:204–9.
J Matern Fetal Neonatal Med Downloaded from informahealthcare.com by Nyu Medical Center on 10/16/14 For personal use only.
4
B. Cakmak et al.
8. Agrawal Y, Carey JP, Della Santina CC, et al. Disorders of balance and vestibular function in US adults. Arch Intern Med 2009;169: 938–44. 9. McCrory JL, Chambers AJ, Daftary A, Redfern MS. Dynamic postural stability during advancing pregnancy. J Biomech 2010;43: 2434–9. 10. Yu Y, Chung HC, Hemingway L, Stoffregen TA. Standing body sway in females with and without morning sickness in pregnancy. Gait Posture 2013;37:103–7. 11. Cachupe WC, Shifflett B, Kahanov L, Wughalter EH. Reliability of Biodex Balance System measures. Meas Phys Educ Exerc Sci 2001; 5:97–108. 12. Testerman C, Vander Griend R. Evaluation of ankle instability using the Biodex Stability System. Foot Ankle Int 1999;20:317–21. 13. Calguneri M, Bird H, Wright V. Changes in joint laxity occurring during pregnancy. Ann Rheum Dis 1982;41:126–8. 14. Gilleard W, Brown J. Structure and function of the abdominal muscles in primigravid subjects during pregnancy and the immediate postbirth period. Phys Ther 1996;76:750–62. 15. Whitcome KK, Shapiro LJ, Lieberman DE. Fetal load and the evolution of lumbar lordosis in bipedal hominins. Nature 2007;450: 1075–8. 16. Butler EE, Colon I, Druzin ML, Rose J. Postural equilibrium during pregnancy: decreased stability with an increased reliance on visual cues. Am J Obstet Gynecol 2006;195:1104–8. 17. Jang J, Hsiao KT, Hsiao-Wecksler ET. Balance (perceived and actual) and preferred stance width during pregnancy. Clin Biomech (Bristol, Avon) 2008;23:468–76.
J Matern Fetal Neonatal Med, Early Online: 1–4
18. Heinrichs L. Linking olfaction with nausea and vomiting of pregnancy, hyperemesis gravidarum and migraine headache. Am J Obstet Gynecol 2002;186:S215–19. 19. O’Brien B, Naber S. Nausea and vomiting during pregnancy: effects on the quality of women’s lives. Birth 1992; 19:138–43. 20. Goodwin TM, Nwankwo OA, Davis-O’Leary L, et al. The first demonstration that a subset of women with hyperemesis gravidarum has abnormalities in the vestibuloocular reflex pathway. Am J Obstet Gynecol 2008;199:417.e1–417.e9. 21. Dunning K, LeMasters G, Levin L, et al. Falls in workers during pregnancy: risk factors, job hazards, and high risk occupations. Am J Ind Med 2003;44:664–72. 22. Schiff MA. Pregnancy outcomes following hospitalization for a fall in Washington State from 1987 to 2004. BJOG 2008;115: 1648–54. 23. Hue O, Simoneau M, Marcotte J, et al. Body weight is a strong predictor of postural stability. Gait Posture 2007;26:32–8. 24. Corbeil P, Simoneau M, Rancourt D, et al. Increased risk for falling associated with obesity: mathematical modeling of postural control. IEEE Transac Neural Systems Rehab Eng 2001;9:126–36. 25. Cakmak B, Inanir A, Nacar MC, Filiz B. The effect of maternity support belts on postural balance in pregnancy. PM R. 2014 Jan 8. Pii: S1934-1482(13)1234-3. (doi.org/10.1016/j.pmrj.2013.12.012). [Epub ahead of print]. 26. Genc A, Can G, Aydiner A. The efficiency of the acupressure in prevention of the chemotherapy-induced nausea and vomiting. Support Care Cancer 2013;21:253–61.
