The influence of macrosomia on the duration of labor, the mode of delivery and intrapartum complications

Objective This study assessed the perinatal outcome in a series of macrosomic fetuses with mothers from a general obstetric population in whom vaginal delivery was planned. Methods In all, 215 women with macrosomic infants were included from a total of 2,622 deliveries. The pattern of maternal weight gain in pregnancy, the influence of fetal macrosomia on the duration of labor and the delivery outcome were investigated in this group. The main issues studied were the impact of fetal weight on the mode of delivery, the duration of the two stages of delivery and the incidence of intrapartum complications in fetuses larger than 4,000 g in comparison with normal-weight fetuses. Results Complete data were obtained for 594 patients, including 215 macrosomic infants and 379 randomly assessed normal-weight infants. With regard to the mode of delivery, a direct correlation was observed between maternal weight gain and the incidence of secondary cesarean section (P < 0.014) when vaginal delivery was initially planned. There was also a direct correlation between increasing birth weight and a higher incidence of secondary cesarean section and assisted vaginal delivery (P < 0.002). In the first stage of labor, there was a statistically significant difference for obstructed labor between the two groups (P < 0.03). The rate of perineal injuries and the incidence of postpartum hemorrhage were similar in the two groups. Conclusions As some of the risk factors identified are known prior to delivery, every woman in whom there is a suspicion that the fetus may weigh up to 4,500 g should receive individual guidance regarding special intrapartum and perinatal conditions.