Intrapartum caesarean rates differ significantly between ethnic groups--relationship to induction.

Abstract

OBJECTIVE: Given international variation in obstetric practices and outcomes, comparison of labour outcomes in different ethnic groups could provide important information regarding the underlying reasons for rising caesarean delivery rates. Increasing numbers of women from Eastern European countries are now delivering in Irish maternity hospitals. We compared labour outcomes between Irish and Eastern European (EE) women in a large tertiary referral center. STUDY DESIGN: This was a prospective consecutive cohort study encompassing a single calendar year. The cohort comprised 5550 Irish and 867 EE women delivered in a single institution in 2009. Women who had multiple pregnancies, breech presentation, and elective or pre-labour caesarean sections (CS) were excluded. Data obtained from birth registers included maternal age, nationality, parity, gestation, onset of labour, mode of delivery and birth weight. RESULTS: The overall intrapartum CS rate was 11.4% and was significantly higher in Irish compared to EE women (11.8% vs. 8.8%; p=0.008). The proportion of primiparas was lower in Irish compared to EE women (44.8% vs. 63.6%; p<0.0001). The intrapartum CS rate was almost doubled in Irish compared to EE primiparas (20.7% vs. 11.0%; p<0.0001). Analysis of primiparas according to labour onset revealed a higher intrapartum CS rate in Irish primiparas in both spontaneous (13.5% vs. 7.2%; p<0.0001) and induced labour (29.5% vs. 19.3%; p=0.005). Irish women were older with 19.7% of primiparas aged more than 35, compared to 1.6% of EE women (p<0.0001). The primigravid CS rate in Irish women was significantly higher in women aged 35 years or older compared women aged less than 35 (30.6% vs. 18.3%; p<0.0001) consistent in both spontaneous and induced labour. The primiparous induction rate was 45.4% in Irish women compared to 32% in EE women, and more Irish women were induced before 41 weeks gestation. CONCLUSION: The results highlight that primigravid intrapartum CS rates were significantly lower in EE compared to Irish women. This could potentially be explained by the younger age and lower induction rates in EE primiparas. Further studies are required to determine the factors for this significant difference in labour outcomes for these two Caucasian groups.