A new study has revealed that mothers who drink alcohol during pregnancy might damage the fertility of their future sons.
The doctors have found that if mothers had drunk 4.5 or more drinks a week while pregnant, then the sperm concentration of their sons, measured about 20 years later, was a third lower in comparison to men who were not exposed to alcohol while in the womb.
"Our study shows that there is an association between drinking a moderate amount of alcohol (about four to five drinks a week) during pregnancy and lower sperm concentrations in sons. However, because this is an observational study we cannot say for certain that the alcohol causes the lower sperm concentrations," said Dr Cecilia Ramlau-Hansen, senior researcher at the Department of Occupational Medicine, Aarhus University Hospital.
The researchers studied 347 sons of 11,980 women with singleton pregnancies who were recruited to the Danish "Healthy habits for two" study between 1984-1987.
They found that sons of mothers drinking 4.5 or more alcoholic drinks a week had average sperm concentrations of 25 million per millilitre, while the sons who were least exposed to alcohol had sperm concentrations of 40 million/ml.
After adjusting for various confounding factors, they found the sons in the group most exposed to alcohol had an average sperm concentration that was approximately 32 percent lower than that in the least exposed group.
Hansen said: "The reduced sperm concentrations in the most exposed men are rather close to the lower end of the WHO's normal range for fertility. The probability of conception increases with increased sperm concentration up to 40 million/ml and so it is possible that the most exposed men could be less fertile than the least exposed."
"Our finding that sons prenatally exposed to 1-1.5 drinks per week had higher semen volume and total sperm count compared to the least exposed group is not surprising and is quite a common finding when studying alcohol. It could indicate that small amounts of alcohol have a beneficial effect (for example, on the semen-producing tissue in the foetal testes), but, in fact, we believe this result may be biased by the characteristics of the women drinking small amounts of alcohol during pregnancy or by inaccurate reporting of alcohol consumption. Therefore, it is not possible to draw a firm conclusion from this result," she added.
"If further research shows that maternal alcohol consumption is a cause of reduced semen concentration in male offspring, then we are a bit closer to an explanation of why semen quality may have decreased during the last decades and why it differs between populations. If exposure to alcohol in foetal life causes poor semen quality in adult life, we would expect that populations with many pregnant women drinking, possibly heavily, in pregnancy would have lower fertility in comparison with populations of where pregnant women do not drink," concluded Hansen.
The findings of the research were presented at the 26th annual meeting of the European Society of Human Reproduction and Embryology in Rome. (ANI)