A MORPHOMETRIC STUDY OF MATERNAL SMOKING ON APOPTOSIS IN THE SYNCYTIOTROPHOBLAST

Objectives: To study syncytiotrophoblast apoptosis in the placenta of smoking and non-smoking pregnant women. Methods: Twelve neonates, preg nancies and placentas were available for study. Eight mothers smoked d uring pregnancy and the remaining four were non-smokers used as contro l subjects. The main outcome measure was the apoptotic syncytiotrophob last index for each group. Apoptosis was detected by immunohistochemis try using the TUNEL method and quantitatively measured using a Merz gr id. The apoptotic syncytiotrophoblast index was calculated as the rati o of mean apoptotic labeling to percent terminal villus area using hig h-power field microscopy. Results: Significant differences in apoptoti c syncytiotrophoblast index were observed between the control group (1 5.06 +/- 3.72) and the smoker group (1.66 +/- 1.74) (P < 0.0001, Mann- Whitney test), but no differences were detected in clinical or morphom etric data between groups. Conclusions: The human placental syncytiotr ophoblast undergoes apoptosis and this process is associated with inhi bition of apoptosis by the smoking habit. The same way as the presence of trophoblast apoptosis is associated with modifications of the mate rnal-fetal exchange, the inhibitory effect of the smoking habit on syn cytiotrophoblast could be responsible for the poor prognosis of pregna ncy in the presence of maternal smoking. (C) 1998 International Federa tion of Gynecology and Obstetrics.