Women who smoke during early pregnancy may predispose their daughters to obesity and gestational diabetes later in life concludes a new study published in Diabetologia.
The researchers used data from the Swedish Medical Birth Register to group 80,189 expecting women into three categories: non smokers, moderate smokers (1 to 9 cigarettes per day) and heavy smokers (over 9 cigarettes per day).
The daughters who were moderately exposed to cigarette smoking in the womb had a 62% increased risk of gestational diabetes while those whose mothers were heavy smokers had a 52% increased risk.
The risk of obesity rose by 36% among daughters who were moderately exposed to smoking in-utero. Those who were heavily exposed had a 58% increased risk of being obese.
The authors reported similar associations after they adjusted for delivery mode, gestational age, BMI, birth weight, age and parity.
How smoking leads to diabetes and obesity
- When a pregnant woman smokes, less oxygen and fewer nutrients are available to the baby — this could cause the foetus to be malnourished. According to the researchers, animal studies show that malnutrition in-utero could alter the regulation of appetite and the feeling of fullness. This could cause overeating and hence, weight gain.
- Nicotine from cigarette smoke appears to have a lethal effect on the insulin-producing beta cells of the pancreas. It also increases formation of fat cells. The toxin could thus make the foetus more vulnerable to obesity and diabetes later in life.
- The scientists pointed out that smoking may alter the genetic code of the baby, thus predisposing the unborn child to diabetes and obesity.
The authors warn that unaccounted differences in diet and other factors between families with and without smokers may very well have influenced the results observed.
Smoking during pregnancy: what other studies have found
Researchers from the University College London found that smoking while pregnant increases the risks that the mother will deliver a baby with birth defects such as clubfoot, malformed limbs and facial anomalies. Heart defects have also been reported.
Another study showed that women exposed to second-hand smoke were more likely to give birth prematurely — a baby born before the 36th week of gestation has up to 50% increased risk of death in early adulthood.
Reduced fertility in offspring
Cigarette smoke contains toxic chemicals known as PAHs. These substances have been shown to decrease the foetus’ embryonic germ cells — these are the cells which will later develop into sperm or egg cells.
Impaired cognitive function
Studies show that children whose mothers smoke during pregnancy are at higher risks of ADHD, mental retardation and intellectual impairment.
Baby’s immature organs are affected
The toxins in cigarette smoke appear to prevent the foetus heart and lungs from developing properly. This makes the baby more vulnerable to heart disease, asthma and lung infections during early childhood.
Butt out for baby: you can do it
It’s never too late to stop smoking but it does require support and professional advice. Contact the NHS support website today.
Mattsson et al (2013). Maternal smoking during pregnancy and daughters’ risk of gestational diabetes and obesity. Diabetologia. 56(8):1689-1695.