Evaluation of maternal and perinatal outcomes in pregnancy with high BMI

Maternal obesity is a significant risk factor for unfavourable outcomes during pregnancy. However, the extent of this relationship is poorly defined in Irish mothers.

This study was to compare maternal and perinatal outcomes between obese and non-obese mothers in an Irish population.

A retrospective comparative study was conducted in a secondary level maternity unit for births recorded between January 2018 and January 2019 and 2,793 women were included. BMI calculated at booking visit was used to compare obese (BMI ≥ 30 kg/m²) and non-obese mothers (BMI < 30 kg/m²).

Of 2,793 women included in this study, 2111 had a BMI < 30 kg/m² and 682 had a BMI ≥ 30 kg/m². Obese women were less likely to experience spontaneous onset of labour (33.4% vs. 48.1%, p < 0.001) and more likely to be induced (37.2% vs. 31.0%, p = 0.002). Obesity was associated with a statistically significant increase in stillbirth, fetal macrosomia and emergency caesarean birth rates, whereas operative vaginal deliveries were significantly decreased. Miscarriage, shoulder dystocia, post-partum haemorrhage and spontaneous vaginal deliveries were reduced while elective caesarean birth and low birth weight incidence were increased in obese mothers; however, these results were not statistically significant.

This study highlights the magnitude of obstetric risks that are associated with maternal obesity within Irish population. Implementation of effective intervention strategies to reduce the number of obese women in pregnancy may have beneficial effects on pregnancy outcomes in Ireland.