Peer-reviewed article
Mode of delivery after induction of labour in pregnant women with pre-pregnancy overweight and obesity.
Bjørnerem Å, Kolstad CR, Helmersen TAG, Michelsen TM, Sørbye IK ·
Summary
Written by AI, not yet AICS's view · claude-haiku-4-5-20251001This study examined how pre-pregnancy weight status affects the mode of delivery in pregnant women who had their labour induced. Among 807 women in Norway, those with obesity were more likely to have a caesarean section compared to those with normal weight. However, when other factors were considered, the increased risk was mainly explained by whether women had given birth vaginally before, rather than by obesity alone.
Key points
- Women with pre-pregnancy obesity had a higher caesarean section rate (21.7%) compared to normal weight women (14.9%)
- The risk of caesarean section increased with pre-pregnancy BMI (p = 0.03)
- After adjusting for age, parity and previous delivery mode, obesity was no longer a statistically significant independent risk factor
- Parity and previous vaginal delivery history were more influential than obesity in determining mode of delivery
Limitations
The study focuses on obstetric outcomes in pregnant adults rather than child well-being outcomes. It does not measure impacts on newborn or child health, development, or any dimension of child welfare.
Abstract
Background The proportion of pregnant women with overweight or obesity whose labour is induced is increasing. The aim of this study was to examine the relationship between pre-pregnancy body mass index (BMI) and mode of delivery among pregnant women whose labour was induced. Material and method The study included women with singleton pregnancies, a fetus in cephalic presentation and a liveborn child, whose labour was induced at the University Hospital of North Norway, Tromsø in the period 2016-18. The mode of delivery was compared for women with a pre-pregnancy BMI < 25 kg/m2, overweight (BMI 25.0-29.9 kg/m2) and obesity (BMI ≥ 30 kg/m2). Results In the study, we included 807 women whose labour was induced. Of these, 402 had a pre-pregnancy BMI < 25 kg/m2, 202 had overweight and 203 had obesity. Of these, 306 (76.1 %), 149 (73.8 %) and 140 (69.0 %) had a spontaneous birth, while 60 (14.9 %), 40 (19.8 %) and 44 (21.7 %) had a caesarean section. As pre-pregnancy BMI increased, the proportion of spontaneous births decreased (p = 0.06), while the proportion delivered by caesarean section increased (p = 0.03). Women with obesity whose labour was induced were at a higher risk of caesarean section (odds ratio 1.6 (95 % confidence interval 1.0-2.4)) compared to those with a BMI < 25 kg/m2. After adjusting for age, height, prolonged rupture of membranes, parity and previous mode of delivery, the odds ratio remained virtually unchanged, but was no longer statistically significant (odds ratio 1.5 (95 % CI 0.9-2.4)). Interpretation Pre-pregnancy obesity was linked to a higher risk of caesarean section following induced labour, but the risk was more significantly influenced by being primiparous or multiparous without a prior vaginal delivery than by obesity itself.