The more women drink during pregnancy, the lower the sperm counts of their sons tend to be in adulthood, Danish researchers say.
The conclusion of the is based on a study of the sperm counts of 347 young men born in the mid-1980s whose mothers completed a questionnaire about their lifestyle habits, including consumption of alcohol, while they were pregnant.
According to the researchers, sons of mothers who reported consuming at least 4.5 alcoholic drinks per week during pregnancy had average sperm concentration of 25 million/ml - a third lower than the 40 million/ml average count measured among sons whose mothers had fewer than one drink per week while they were pregnant.
"Our study shows that there is an association between drinking a moderate amount of alcohol (4.5 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," Dr. Cecilia Ramlau-Hansen, senior researcher at the Department of Occupational Medicine, Aarhus University Hospital, said.
"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," she said.
The finding is the latest release from a large-scale, ongoing study by the Danish Epidemiology Science Centre of children born between 1984 and 1987 in the cities of Odense and Aalborg.
About 12,000 mothers, 11,500 fathers and 11,300 children were involved in the "Healthy Habits for Two" project which studies the effects of everything from air pollution to nutrition to alcohol and tobacco to occupation and social position on birth outcomes and later life.
The sperm-count research was presented at the 26th annual meeting of the European Society of Human Reproduction and Embryology in Rome last week.
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