EFFECTS OF MATERNAL SMOKING ON AMNIOTIC-FLUID VOLUME AND FETAL URINE OUTPUT

The purpose of this study was to assess the effects of maternal smokin g on amniotic fluid volume and fetal urine output. Seventeen women (10 smokers and 7 nonsmokers) were serially assessed through pregnancy. S moking status was determined by self-report and carbon monoxide manome try. Amniotic fluid volume was assessed by sonographically measuring t he maximum vertical pocket, the amniotic fluid index, and the two dime nsions of the largest pockets. The coronal area formula was used to ca lculate bladder volume at 5-minute intervals for 20 minutes. Urine out put was calculated from serial measurements of bladder volume. The mea n gestational age of the first session was 26.8 (2.7) weeks, of the se cond session 32.4 (1.6) weeks, and of the last session 36.9 (2.1) week s. In the univariate analysis there were no differences between smoker s and non-smokers at any of the three visits for gestational age, feta l weight, maximum vertical pocket, amniotic fluid index, two-dimension al maximum pocket, and urine output. In the regression model, while co ntrolling for gestational age, smoking status could not predict signif icant differences in any parameter. Maternal smoking does not appear t o affect either amniotic fluid volume or fetal urine output.