Women who – foolishly – smoke during pregnancy should have been told by their doctors that tobacco use at such a critical time can endanger their infants by raising their risk for being born prematurely and at a lower birth weight, as well as suffering from developmental delays, compared to babies born to non-smoking women. 

Researchers at the Hebrew University in Jerusalem have found – based on a secondary analysis of US data on 222,408 women who gave birth between 2009 and 2015 – that smoking during pregnancy can harm the women themselves by significantly raising the risk of developing gestational diabetes. This risk can make it more likely that the women and their child will develop type II diabetes when they are older. The number of women included was very large, and thus, the findings were very convincing. 

Gestational diabetes is a condition in which a woman who does not suffer from glucose intolerance develops high blood sugar while being pregnancy. This diagnosis thus usually comes as a surprise to women, but it does raise the risk of a pregnancy complication called pre-eclampsia, in which they develop high blood pressure and sometimes damage to the liver and kidneys.

Preeclampsia usually begins after 20 weeks of pregnancy in women whose blood pressure had been normal. Babies born to mothers with poorly treated gestational diabetes are at increased risk of being too large (macrosomia), having low blood sugar after birth, and jaundice. If untreated, it can also result in a fetus being born dead (stillbirth). 

Gestational diabetes affects between 7.6% and 9.2% of pregnant women in the US and occurs mostly during the last trimester of pregnancy. Such a pregnancy is often concluded with birth by cesarean section.

Smoking during pregnancy is one of the most significant risk factors for poor pregnancy outcomes.  In the US, 23 % of all women before getting pregnant smoking, while 10.7% of all women continue to smoke during their pregnancy or don’t light up themselves but are exposed to that the tobacco smoke of others. 

The matter was investigated by an international research team headed by Dr. Yael Bar-Zeev at the Hebrew University of Jerusalem’s Braun School of Public Health and Community Medicine, in collaboration with Dr. Haile Zelalem and Professor Ilana Chertok at Ohio University. They have just published their findings in the journal Obstetrics & Gynecology. The article was titled “Association Between Prenatal Smoking and Gestational Diabetes Mellitus.” 

Bar-Zeev and her team studied data collected by the US Centers for Disease Control and Prevention (CDC) that are called the Pregnancy Risk Assessment Monitoring System (PRAMS).  Of the 222,408 women whose data they studied, 12,897 (5.3%) were diagnosed with gestational diabetes.  

Among all of the participants, the vast majority were nonsmokers for more than two years before pregnancy, almost three percent quit before their pregnancies, 11.8% quit smoking during pregnancy and 6.7% reduced the number of cigarettes they smoked.

The researchers found that pregnant women who smoke the same or higher number of cigarettes per day as they did before their pregnancy are nearly 50% more likely to develop gestational diabetes.  Those pregnant women who cut down on their number of cigarettes still have a 22% higher risk than women who never smoked or who quit smoking two years before they became pregnant.  

“Ideally, women should quit smoking before they try to become pregnant,” Bar-Zeev urged.  “Further, due to the high risks involved, it’s imperative that pregnant smokers have access to pregnancy-specific smoking cessation programs.  Currently, in the US and Israel, these services are not accessible enough or not tailored for pregnant women and that needs to change”. 

Smoking, they authors wrote, is considered an independent risk factor

for type 2 diabetes. “A possible explanation of the association is the effect of smoking on increased oxidative stress, inflammation, hyperglycemia and insulin resistance, although the exact mechanism of action is yet to be determined. Prenatal smoking has not been conclusively identified as a factor associated with gestational diabetes, with studies showing mixed results. In addition, smoking cessation may increase appetite and weight gain, which are associated with gestational diabetes.”

So, kick your smoking habit and keep away from tobacco smoke during your pregnancy – for the baby’s and for your own benefit!