Maternal smoking and fetal lung signals – an in utero MRI investigation

Abstract

To investigate whether fetal lung signals and fetal lung signal progression over gestation observed on magnetic resonance imaging are different in mothers who reported smoking during pregnancy compared with nonsmoking controls. Cross-sectional retrospective study of 100 consecutive singleton pregnancies that underwent magnetic resonance imaging. Fetal lung-liver signal intensity ratios of 18 fetuses of mothers who reported smoking during pregnancy were compared with 82 fetuses of nonsmoking controls. Average gestational age at magnetic resonance imaging was 26.4 ± 5.2 weeks (Range 18.4-38.2 weeks). Cases reported smoking between 2 and 15 cigarettes per day. The mean number of cigarettes per day for cases was 9.2 ± 3.4. Mean fetal lung-liver signal intensity ratios did not differ significantly between the two groups (p = 0.8). They showed a linear increase with gestational age (r(2) = 0.3). Multiple regression analysis of lung-liver signal intensity ratios using gestational age and smoking status as predictors revealed a significant influence of gestational age (p < 0.0001) but not maternal smoking status (p = 0.8) on fetal lung-liver signal intensity ratios. Fetuses of mothers who reported smoking during pregnancy show similar lung signals and lung signal progression over gestation on magnetic resonance imaging as nonsmoking controls.