Factors affecting elective cesarean section in women with multiple pregnancy in Caruban, Indonesia

Introduction

Multiple pregnancies are currently much more common than in the past as a result of older maternal age and pregnancies resulting from assisted reproductive technologies¹. Multiple pregnancy accounts for 1% to 4% of total births, with a prevalence ranging from 0.9% to 1.4% in England and Wales and 0.9% to 2.4% in Brazil². The lowest incidence rate of multiple pregnancy is in East Asia (fewer than eight twin births in 1000)³. Multiple pregnancy is associated with higher maternal and perinatal risks than singleton pregnancy, including pre-eclampsia, hypertension, hyperemesis, postpartum haemorrhage, premature rupture of the membranes and anaemia^2,4. The rate of perinatal mortality is 2–3 times higher in multiple pregnancy than in singleton newborns. Multiple pregnancy can increase preterm birth, foetal growth restriction, low birth weight and intrapartum anoxia⁵.

A case complicated by multiple pregnancy has the same delivery options as a singleton pregnancy: caesarean or vaginal delivery. This choice depends on multiple factors and remains controversial in numerous studies. Many important factors are involved when determining the delivery method, including women’s parity, foetal weight, foetal presentation, gestational weight and maternal clinical conditions⁶. Some studies have explained that if both foetuses are in a cephalic presentation, the vaginal mode is preferred⁷. Vaginal delivery is possible if the foetus weighs more than 1500 grams. Caesarean delivery is the best choice when the first foetus is non-cephalic. Another large retrospective population study found that compared with caesarean delivery, increased neonatal morbidity and mortality were observed for the second twin when vaginal delivery was performed. That study also indicated that elective caesarean delivery is safer than vaginal delivery and results in the best maternal and perinatal outcomes⁸. However, although evidence for the preference of an elective caesarean section for multiple pregnancy is lacking, the rates of elective caesarean section for multiple pregnancy have increased throughout the world⁹. The main objective of this study was to evaluate and provide reliable information on the contributing risk factors such as maternal characteristics, obstetric histories and recorded pregnancy complications that influenced the decision to undertake a caesarean section or vaginal birth in multiple pregnancy cases.

Methods

Results

As shown in Table 1¹¹, among the 47 mothers who met our inclusion criteria, more than half were between 21 and 35 years old, and most had a low educational status and worked as private employees. Additionally, 12 women underwent a vaginal delivery whereas the other 35 women birthed their babies abdominally. Thus, more women underwent a caesarean section than gave birth vaginally. Figure 1 indicates that the main indication for a caesarean section in this study was a caesarean scar, followed by malpresentation and foetal distress. Perinatal complications were principally dominated by malposition of the foetuses, which were not in the vertex position. During the labour process, 18 of the 47 women suffered prolonged labour. Six women came to the hospital with a history of premature membrane rupture without uterine contractions. Gestational hypertension was also reported in 12 women and 11 women had Hb levels below 10 g/dL in their last recorded Hb examinations in late pregnancy.

Figure 1. Cesarean section indications.

Based on the analysis, the average age at delivery differed significantly between women who underwent caesarean and vaginal delivery (p = 0.00). Other maternal characteristics including primiparous as the most common parity status (p = 0.73), educational status (p = 0.46) and being unemployed (p = 1.00) did not differ significantly between the two groups of women stratified by delivery method.

Additionally, we evaluated the obstetric history of the included mothers. In total, 21 women had a history of previous caesarean section, which was found to significantly increase the likelihood of undergoing another caesarean section (OR = 16.5, 95% CI = 1.91 to 142.29, p = 0.02). Women who suffered prolonged labour during their delivery were significantly less likely to undergo a caesarean delivery (OR = 0.20, 95% CI = 0.49 to 0.81, p = 0.03). Women who did not experience malpresentation of their foetuses during pregnancy were more likely to undergo a caesarean delivery (OR = 8.25, 95% CI = 0.95, 71.09, p = 0.03). However, in this study, premature rupture of the membrane, gestational hypertension and gestational anaemia did not significantly contribute to an increased likelihood of a caesarean section. Pregnancy term did not differ significantly between the women undergoing caesarean section and vaginal birth. Neonatal outcomes including 1-minute APGAR (appearance, pulse, grimace, activity, and respiration) scores and babies’ birth weights did not differ significantly for both the first and second babies between both groups of delivery methods (Table 2¹¹). When comparing caesarean section and vaginal delivery, both first babies (p = 0.82) and second babies (p = 0.38) had APGAR scores ≥ 7 (Table 2¹¹). The first babies delivered after caesarean section vs vaginal birth did not differ significantly (2114 grams ± 469.37 vs 1938.33 grams ± 562.36, p = 0.29) (Table 2¹¹). Similarly, the second babies following caesarean section vs vaginal birth also did not differ significantly (2038 ± 478.75 vs 1878.33 ± 417.45, p = 0.31) (Table 2¹¹).

Discussion

Based on the study results, a planned caesarean section appears preferable to a vaginal birth for women with multiple pregnancies when the mothers have a history of previous caesarean section and in cases of malpresentation of the foetus. The neonatal birth weight and 1-minute APGAR scores of the twin babies born by both methods of delivery in this study were similar. Adverse perinatal outcomes including perinatal mortality and transient tachypnea of the newborn, were not significantly different between groups. However, the second twin had a higher risk of suffer perinatal outcomes than the first following vaginal delivery¹². Combined vaginal/caesarean delivery is another option. However, it may be complicated by a longer interval of prolonged rupture of membranes, leading to endometritis and sepsis in the second twin.¹³. A large nationwide study of multiple pregnancy cases identified a greater risk of uterine rupture in women who delivered their babies via natural birth¹⁴. However, previous studies reported that there was no difference in the perinatal outcomes between caesarean section and vaginal birth in multiple pregnancy^15,16. Conversely, maternal aspects are an important consideration when choosing the delivery mode in women with a twin pregnancy. However, some studies have reported that the use of forceps or vacuum extractions in vaginal birth could contribute to birth lacerations that may lead to gynaecologic morbidities^17–20.

In this comparison study between planned caesarean section and vaginal delivery, we found that there was a significant difference in the maternal age between the two groups. This finding was supported by a previous study that showed a significantly increased trend of caesarean delivery with increased maternal age²¹. However, a study from Korea found there was no significant difference caesarean section rates in women with multiple pregnancies according to maternal age²². The other difference we identified was that women undergoing caesarean section were more likely to have undergone a previous caesarean section. A similar study comparing women having caesarean sections and vaginal births reported that caesarean section was significantly more likely to occur in women with previous caesarean histories²³. Another report revealed that caesarean sections must not be considered mandatory for multiple pregnancies²⁴. However, a study from Myles (2009) demonstrated that caesarean sections had a higher success rate and a lower probability of developing uterine rupture than vaginal delivery²⁵.

This study found that women who underwent labour augmentation by using misoprostol or oxytocin did not have a higher probability of caesarean section. Supporting our finding, a study by Arulkumaran showed that approximately 78% of women with a caesarean scar who were administered labour augmentation had safe vaginal births whereas the other women who had undergone second caesarean sections were suffering from cephalo-pelvic disproportion²⁶. Furthermore, a prospective cohort study on 153 women with caesarean scars in Saudi Arabia suggested that labour induction to promote vaginal delivery did not contribute to the increased likelihood of a second elective caesarean section or adverse effects on neonatal outcomes²⁷. By contrast, a study in Sweden reported the increased likelihood of caesarean delivery after performing labour induction using oxytocin and cervical ripening in women with multiple pregnancy²⁸. Another study also explained that labour induction or augmentation was safe for women to promote successful vaginal delivery in multiple pregnancy cases²⁹.

In our study, we found that non-cephalic presentations did not significantly increase the likelihood of undergoing a caesarean section. Our results supported previous studies that reported relatively similar outcomes for women with non-cephalic presentations who delivered their babies abdominally and vaginally^30,31. Furthermore, a caesarean section in multiple pregnancies with non-cephalic presentations is likely to occur following external cephalic attempts¹¹. A report from France suggested that the type of presentation must not be considered the main consideration for caesarean section in multiple pregnancies¹⁰.

Our findings demonstrate that women with multiple pregnancies had a higher tendency to deliver their babies abdominally via caesarean section. Maternal age and previous history of a caesarean section should be considered when determining whether to perform a caesarean delivery in women with multiple pregnancies. However, the supporting findings are still limited. This study also noted that malpresentation and labour augmentation do not increase the likelihood of a caesarean section compared with vaginal delivery. However, this finding was rather weak due to the small size of the study population, and thus choosing between a caesarean section and vaginal delivery must be made after considering the patient’s preference and the risks and benefits.

Data availability