The peri-partum management of pregnancies with macrosomic babies weighing ≥4,500 g at a tertiary University Hospital

The management of fetal macrosomia diagnosed antenatally presents a dilemma to the obstetrician. We retrospectively reviewed the peripartum management of singleton pregnancies, which ended in the delivery of a macrosomic baby (birth weight >= 4,500 g) in our unit between 1995 and 1999. This was to determine first, the associated maternal and neonatal morbidity and second, whether the lack of consensual management in our unit influences outcome. Over the 5-year period, there were 380 macrosomic births out of 26,974 deliveries; an incidence of macrosomia of 1.4%. The mean birth weight was 4,697 +/- 330 g (range 4,500-5,560 g). The onset of labour was spontaneous in 234 (61.6%) cases, 120 (31.6%) were inductions and 26 (6.8%) were elective caesarean sections. Of the 354 planned vaginal deliveries, 233 (65.8%) were spontaneous, 62 (17.5%) were operative vaginal deliveries and 59 (16.7%) were emergency caesarean sections. There was no relationship between the rate of successful vaginal delivery and birth weight. There were 40 (13.6%) cases of shoulder dystocia compared with 0.9% in the non-macrosomic population (p < 0.001). Emergency caesarean sections and shoulder dystocia were significantly more common with babies weighing >= 5,000 g (28.9% vs 15.2%, p < 0.002 for caesarean section and 25.8% vs 11%, p < 0.001 for dystocia). We therefore recommend that where the estimated fetal weight is > 5,000 g, an elective caesarean section should be considered. Variations in the care provided by different consultants did not have any effect on outcome. Induction for fetal macrosomia alone did not improve outcome but was associated with a significantly higher emergency caesarean section rate and should therefore be discouraged.