Quitting smoking in pregnancy tied to weight gain and high HDP risk, but lower stillbirth risk

Smoking discontinuation during pregnancy is associated with both positive and negative outcomes, such as reduced risk of stillbirth but higher risk of hypertensive disorders of pregnancy (HDP) and weight gain, according to a study.

Researchers performed a cross-sectional analysis of data from 22,191,568 women. They evaluated the associations between smoking status, body mass index, gestational weight gain, HDP risk, and other clinically important outcomes.

HDP occurred among 6.8 percent of women who were never-smokers, 8.6 percent of those who quit smoking during pregnancy, and 7.0 percent of those who smoked persistently.

On multivariate analysis, the rate ratio of HDP was markedly higher among women who quit smoking during pregnancy, especially those with excessive gestational weight gain. These associations became more pronounced after adjusting for potential biases and unmeasured variables.

Finally, the rate of stillbirth among women who persistently smoked was about sixfold greater than among those who never smoked (2.3 percent vs 0.4 percent). There was no difference between women who quit smoking and those who never smoked (0.4 percent for both).

In light of the findings, it is important that pregnant women advised to quit smoking should also receive counselling on nutrition and exercise to prevent excessive gestational weight gain, the researchers said.