Oligohydramnios, small for gestational age and pregnancy outcomes: an analysis using precise measures

Marginal or decreased amniotic fluid volume by ultrasound estimate and fetal growth restriction have been shown to be significantly associated with perinatal mortality. The association of fetal growth restriction and precisely measured amniotic fluid volume is unknown. The purpose of this study was to determine if adverse pregnancy outcomes are more likely in pregnancies complicated by small-for-gestational-age (SGA) neonates and dye-determined oligohydramnios.

Admissions to neonatal intensive care unit (NICU) and other pregnancy outcomes were analyzed in parturients with known amniotic fluid volume, calculated by the dye-dilution technique. The pregnancy outcomes of those with oligohydramnios and SGA were compared with pregnancies complicated by just one of these two conditions and pregnancies with normal fluid and birth weight.

Of 202 patients, oligohydramnios was present in 26% (53), SGA in 15% (30) and both conditions in (5%) (11). Logistic regression, controlling for gestational age, demonstrated that the combination of oligohydramnios and SGA, compared to normal growth and fluid strongly predicted NICU admission (OR 11.1; 95% CI 2.1-59.2) but not other complications. (OR 4.8; 95% CI 0.3-62.9).

SGA with oligohydramnios significantly increases the likelihood of a NICU admission, but not other morbidity.