[Perinatal risk in significant macrosomia. A study based on the databank of the Professional Society of Swiss Gynecologic Clinics 1983-1992].

A comparison of a group of births with severe macrosomia with a group of normal birth weight was made based on the data from the "Arbeitsgemeinschaft schweizerischer Frauenkliniken" (ASF), a work group of Swiss departments of obstetrics and gynaecology. During the period from 1983 to 1992 there were 2911 births of infants weighing more than 4500 g and 222,336 births of infants weighing between 3000 and 4000 g. Overall, the births of the macrosomic infants were more difficult, the rates of secondary Caesarean sections higher and the fetal outcomes poorer. The rates of shoulder dystocia, fracture of clavicle and palsy were higher. Only the last three complications were dependent on the mode of birth. In order to avoid, at least partially, palsy as the most serious of the complications of shoulder dystocia, it has been proposed to perform primary Caesarean section whenever the estimated birth weight is over 4500 g. Indeed, in our study, a part of the palsies had not occurred if all newborn weighing more than 4500 g had been delivered by Caesarean section. However, due to the difficulty in estimating the birth weight in utero, the high occurrence of spontaneous recovery from palsy and the high incidence of palsy in the comparison group, we could not find a clear proof of the necessity to perform primary Caesarean sections of all infants having estimated birth weights of over 4500 g.