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 “It is harder for men with low sperm counts to conceive children, or
it may take a longer time to make the partner pregnant,” said Dr.
Christine Wohlfahrt-Veje, a researcher at the University of
Copenhagen who wasn’t involved in the study.
“If women want to have grandchildren, they shouldn’t smoke,”
Wohlfahrt-Veje added by email.
To see how exposures in the womb might influence men’s reproductive
system later in life, researchers contacted men in their early 20s
whose mothers had participated in a maternal and infant health study
during pregnancies two decades earlier.
They collected sperm samples from 365 men and did testicular
ultrasounds on 404 men.
Researchers looked at median sperm production, or the amount
produced by at least half the men in the study. It was about 19
percent lower among the men whose mothers smoked during pregnancy.
Men born prematurely, a risk that goes up when women smoke during
pregnancy, also had lower testosterone in adulthood.
Low testosterone levels are associated with erectile dysfunction,
reduced sex drive and decreased sperm count.
Men who were a healthy size in utero were also less likely to have
low sperm counts than men who were unusually small or large as they
developed during pregnancy, the study found. Smoking can stunt
growth in utero.
Maintaining a healthy weight during childhood may also help with
reproductive health, researchers note in the Journal of Clinical
Endocrinology and Metabolism, online June 24.
Men who consistently had a healthy weight during childhood and
adolescence tended to have larger testicular volume and higher
testosterone levels in adulthood.
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One limitation of the study is that some men dropped out or opted
out of the testicular function tests, which may bias the results,
the authors note.
Even so, there’s plenty of solid evidence proving that women
shouldn’t smoke during pregnancy. Among other things, it can
increase the odds of complications during pregnancy and premature
birth, impair brain development in utero and increase the odds of
breathing difficulties and other childhood health problems like
hyperactivity.
The study findings should give women yet another reason to avoid
smoking during pregnancy, said lead study author Dr. Roger Hart of
the University of Western Australia.
“It is a general healthy lifestyle message that women should not
smoke in pregnancy, they should only start to try to conceive when
they are in their optimal health, and when any co-existing medical
conditions have been optimized, as this is associated with good
fetal growth through pregnancy and a reduced risk of premature
delivery,” Hart said by email.
“Plus of course they should not smoke when pregnant – and should
ideally cease before they start to try to conceive,” Hart added.
SOURCE: http://bit.ly/29JNtu5
J Clin Endocrinol Metab 2016.
[© 2016 Thomson Reuters. All rights
reserved.] Copyright 2016 Reuters. All rights reserved. This material may not be published,
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