Fetal macrosomia and management of delivery.

During the period 1988-1966, 737 pregnancies, in which the infant birth weight was > or = 4000 grams were studied. During the same period there were 11,631 newborns, and 6.3% of them were infants with a birth weight > or = 4000 grams. Normal vaginal delivery occurred in 583 cases (79.1%), vacuum extraction in 24 cases (3.3%) and caesarean section in 130 cases (17.6%). Regarding the caesarean section, 38 (29.2%) of them were elective and 92 (70.8%) were done in different periods of the labour. In these macrosomic babies perinatal death never occurred, but different pathological neonatal outcomes were observed and the majority of these were clavicle abruptions (39 cases: 5.3%). Maternal morbidity observed in the 607 (82.4%) cases with vaginal delivery is characterized by: 60 cases (9.8%) of vaginal and perineal tears, 4 cases (0.6%) of cervical tears, and 2 cases (0.3%) of pubic symphysis traumatic diastasis. Shoulder dystocia is the most likely outcome in fetal macrosomic delivery; for this reason we considered the diagnostic and therapeutic management of this obstetrical complication. Because the normal outcome of neonatal births actually encourages the preference for normal vaginal delivery, we concluded that mothers with macrosomic fetuses can safely be managed expectantly unless there is a high maternal and fetal risk.