The danger of even low levels of drinking and smoking by a pregnant woman have been researched in an extensive new study conducted in South Africa and America.
Alarmingly‚ the researchers said‚ many mothers-to-be are smoking and boozing.
Between 2007 and 2015‚ the international study followed the drinking and smoking behaviour of nearly 12‚000 South African and American women during pregnancy.
Researchers at Stellenbosch University were involved in the study‚ which showed that the combined effect of drinking and smoking in pregnancy compounds the risk for stillbirth and Sudden Infant Death Syndrome (SIDS).
“This is the first study to show that combining these risk factors strengthens the negative effects on stillbirths and SIDS‚” said Professor Hein Odendaal of the Department of Obstetrics and Gynaecology at SU’s Faculty of Medicine and Health Sciences‚ who led the South African chapter of the Safe Passage Study.
The researchers found that women who both drank alcohol and smoked during pregnancy had an almost three times higher risk (2.83 relative risk) of stillbirth compared to women who completely abstained from these behaviours.
Smoking alone had a relative risk of 1.6 for stillbirth‚ while drinking alone had a relative risk of 2.2. This risk increased when these behaviours continued beyond the first trimester of pregnancy (12 weeks gestation).
The study also found a 12 times higher risk for SIDS in cases where women drank and smoked during pregnancy.
In cases where the women drank but did not smoke‚ the risk for SIDS increased by four‚ and when they smoked but did not drink‚ there was a five times higher chance for SIDS.
“What’s particularly alarming is that these behaviours were quite common among study participants. More than half used alcohol (52.3%) sometime during pregnancy‚ and 17% continued drinking throughout the entire pregnancy. Almost half of them smoked (49%) sometime during pregnancy‚ and a third (33%) continued smoking for the duration of the pregnancy‚” said Odendaal.
The majority of women in the study (59.1%) were recruited from a prenatal clinic in Bishop Lavis in Cape Town‚ South Africa‚ while the remaining 40.9% of participants were recruited from two sites in North and South Dakota in the United States.
The study was done in collaboration with the Boston Children’s Hospital and Harvard University in Boston‚ Columbia University in New York‚ the University of South Dakota in Vermillion‚ the University of North Dakota in Grand Forks‚ and a data collection and analysis centre in Boston.