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.
