Does cigarette smoking causes periodic decreases in blood flow to the fetus of mothers with hypertensive disorders and/or impaired fetal growth?

Abstract

Aim: To evaluate the acute effect of maternal cigarette smoking on umbilical and middle cerebral artery blood flow in the fetus of women with and without pre‐eclampsia and/or intrauterine growth restriction.Methods: Pregnant women and ≥24 weeks gestation were recruited from the antenatal ward at Tygerberg Hospital, South Africa. Doppler studies of the umbilical and middle cerebral arteries were performed before and at 10, 20 and 30 min after the mother had smoked a cigarette. The same studies were performed in the non‐smoking controls.Results: There were 13 smoking mothers with hypertension and/or a fetus with growth restriction (group A), 15 non‐smoking mothers with hypertension and/or a growth restricted fetus (group C) and 24 normotensive smoking mothers and an appropriately grown fetus (group B). There was a significant difference in the mean umbilical artery RI and PI values in group A vs. group C (P = 0.03 and 0.004, respectively). There was a significant difference in the mean middle cerebral artery PI between group B and group C (P = 0.004).Conclusions: Smoking significantly reduces the feto‐placental perfusion in pregnancies compromised by hypertension and/or intrauterine growth restriction and should be actively discouraged in these patients.