Fetal lung maturity is not accelerated in preeclamptic pregnancies

Our purpose was to determine whether there is an increased incidence of pulmonary maturity in premature fetuses of preeclamptic women compared with fetuses of matched controls.

A matched cohort study design was used. One hundred twenty-seven strictly defined preeclamptic women who had undergone amniocentesis for pulmonary maturity assessment were matched for gestational age, race, and infant gender to nonhypertensive women with preterm labor who had undergone the same procedure. Patients with multiple gestation, ruptured membranes, diabetes, or prior glucocorticoid treatment were excluded. Lung maturity was assessed with the Lumadex foam stability index test, the lecithin/sphingomyelin ratio, and the TDx fetal lung maturity assay. In addition, the occurrence of respiratory distress syndrome was assessed in 69 of the 127 matched pairs who were also matched for mode of delivery and amniocentesis-to-delivery interval.

There was no significant difference in the incidence of an immature result between the preeclamptic and matched control groups (39.4% vs 38.6%). Likewise, women with mild (n = 63) and severe (n = 64) preeclampsia or with small-for-gestational-age (n = 26) and appropriate-for-gestational-age (n = 101) infants, when analyzed separately, showed no differences in comparison with their matched controls. When analyzed by gestational age subgroups, no specific gestational age range was associated with accelerated maturity. The incidence of respiratory distress syndrome in the 69 matched pairs was slightly, but not significantly, higher in the preeclampsia group (relative risk 1.43, 95% confidence interval 0.94 to 2.37).

This study does not support the contention that fetuses of preeclamptic women exhibit accelerated lung maturation.