Maternal smoking and second-hand smoke linked to increased placental abruption risk

Unlike genetics or age, smoking is a risk factor for numerous diseases that we can actually do something about. By quitting, smokers can minimize these risks. Drawing attention to the harms of smoke inhalation may help direct public health policies and educate people of the effect smoking has on themselves - and everyone around them.

A research group led by Associate Professor Hirotaka Hamada (Tohoku University Hospital) analyzed the contribution of maternal smoking and second-hand smoke exposure to the risk of placental abruption in a Japanese population. Placental abruption is a potentially life-threatening condition for both mothers and babies. Given the dire consequences, providing more knowledge about risk factors that expectant mothers have the ability to modify could make all the difference.

Using data from approximately 82,000 pregnant women across Japan, they calculated the Population Attributable Fraction (PAF) for smoking-related risks. The findings revealed that smoking during pregnancy accounts for 2.8% of placental abruption cases. Additionally, even among non-smoking pregnant women, second-hand smoke exposure contributed to 3.0% of placental abruption cases.

Even if the mother doesn't smoke at all, their partner may smoke at home, thinking it won't be a problem. Our study will hopefully raise awareness that any exposure to smoke is harmful for pregnant women."

Hirotaka Hamada, Associate Professor, Tohoku University Hospital

This study demonstrates the importance of second-hand smoke prevention alongside smoking cessation during pregnancy to safeguard maternal and fetal health. The findings highlight the need to strengthen public policies and educational campaigns to reduce all smoke exposure in public spaces and homes.

The results were published in BMJ Open on March 5, 2025. While this research utilized data from the Japan Environment and Children's Study (JECS), it was conducted under the researchers' responsibility and does not reflect the official views of the Japanese government.