Fetal macrosomia in African women: a study of 249 cases

To determine the incidence and risk factors of macrosomia in a Nigerian centre, and to assess the relation of maternal body mass index (BMI) at birth and of the total weight gain during pregnancy to macrosomia and adverse pregnancy outcome.

A retrospective review of fetal macrosomia over a 5-year period.

Abia State University Teaching Hospital, Aba in Southeast Nigeria.

A total of 9,970 parturients managed from 1 January 1999 to 31 December 2003. Out of 249 documented cases of infants with birth weights ≥4,500 g, 240 (96.4%) maternal and neonatal records of macrosomia were available for review. Maternal and neonatal characteristics of the 240 cases were compared with 8,800 other parturients with singleton fetuses in vertex presentation.

Macrosomic babies represented 2.5% of the infants delivered (249 of 9,970). Most of the mothers (92.5%) were multiparous. Maternal median weight gain was 11 kg (7–15), while the mean weight gain was 12.5 kg. Maternal median BMI was 28.1 kg/m² at delivery, while the mean BMI was 30.3 kg/m² (range 23–40) at delivery. Macrosomia was suspected in 80% on the basis of clinical examination, sonography, and the presence of the following risk factors in association: previous delivery of an infant weighing >4,000 g (62.5%), maternal weight at booking of more than 80 kg (90%), maternal BMI before delivery of ≥28 kg/m² (50%), gestational diabetes mellitus (2.5%), and weight increase of more than 13 kg during pregnancy (5%). The mean birth weight of the babies was 4,750 g (4,500–5,000). The overall CS rate was 15%. The difference in the CS rate between these mothers and the control was not significant (P = 0.41). Only 9 (3.8%) mothers were successfully delivered with the aid of ventouse due to delayed second stage of labor. There was a significant difference in the complication rates between the mothers of large infants and the control (P < 0.001). Four maternal deaths were associated with macrosomia for a maternal mortality rate of 1667/100,000. Four infants had shoulder dystocia and associated injuries. The perinatal mortality rate was 112.5/1,000 births.

The higher the total body weight at birth, the higher the rate of macrosomia. Macrosomia had implications for high morbidity and mortality in the mothers and their infants. Delivery methods need to be evaluated. Caesarean section should be more readily used.