Correlation Between Maternal Obesity, Progress of Labour and Risk of Caesarean Delivery in a Cohort of Nigerian Parturients

Abstract

Background: Maternal obesity is associated with adverse obstetric outcomes including labour complications.This study aimed at assessing the relationship between maternal obesity and course of first stage of labour and risk of caesarean delivery among women in active first stage of labour. Methods: This retrospective cohort study was a secondary analysis of data collected to assess the impacts of maternal obesity on pregnancy outcomes in a Nigerian obstetric population. We compared progress of labour and risk of caesarean delivery in 170 obese [Body mass index (BMI = ≥ 30 Kg/m2)] and 170 normal weight women (BMI = 18.5 – 24.9 Kg/m2) who were in spontaneous labour at term. They were matched for age and parity and exclusion criteria included women with height less than 1.52 metres, medical disorders, previous caesarean section, those that had augmentation of labour and infant weight > 4.0 Kg. Statistical analysis was done using SPSS version 16 (SPSS Inc., Chicago, IL, USA). P < 0.05 was considered significant. Results: Mean age and parity of the women were 30.6 ± 4.8 years and 1.9 ± 1.6 respectively. There was no significant difference between mean cervical dilatation at presentation between the two study groups (4.9 ± 1.8 versus 5.0 ± 1.7, P = 0.64). Cervical dilatation rate per hour was significantly slower in obese group compared to the controls (0.87 ± 0.4 versus 1.2 ± 0.5 cm/hr, P = 0.001). The mean duration of labour was the same in both groups (7.5 ± 3.9 versus 6.2 ± 3.4 hours, P = 0.57). Caesarean section rate increased from 8.8% in the controls to 23.5% among obese women. Obese women had three times higher risk of caesarean delivery compared to the controls (P = 0.002, OR 3.2, 95% CI 1.15 – 8.62) and this was mainly due to failure to progress in labour (P = 0.03). Conclusion: Among women in active phase of labour, maternal obesity was associated with slower rate of cervical dilatation and increased risk of caesarean delivery.