[Sonographic evaluation of the quantity of amniotic fluid. II. Oligohydramnios--significance for the course of pregnancy and labor].

3,274 pregnant women were examined sonographically in this study, with particular emphasis on the quantity of amniotic fluid present. In 8% of the patients a reduced amount of amniotic fluid was seen. If the largest pocket of amniotic fluid was less than 2 cm that particular case was classified as oligohydramnios. If the largest pocket of amniotic fluid was between 2 cm and 3 cm, it was assumed to be in the lower standard range. These cases were compared with a randomly selected control group with normal amounts of amniotic fluid, in respect of the occurrence of complications during gestation and delivery and of the incidence of fetal malformations. Patients with reduced amounts of amniotic fluid showed signs and symptoms of gestosis more often (p less than 0.001) and delivered more often before the 36th week of pregnancy (p less than 0.001) and growth-retarded children (p less than 0.001) than women with standard amounts of amniotic fluid. The incidence rate of Caesarean section was 42%, and hence far above the standard level (p less than 0.001). In oligohydramnios, 13% (p less than 0.001) of the children had severe fetal malformation, whereas, with an amount of amniotic fluid in the lower standard range, only 5.5% (not significant) showed severe foetal malformation. The stated sonographic criteria are suitable as an objective measure for quantifying the amount of amniotic fluid.