Smoking during pregnancy can 'masculinize girls in the womb' and damage their future fertility: Study
Daughters of women who smoked during pregnancy might suffer from hormonal and reproductive health problems in the long-term.
According to researchers, besides the presence of over 4,000 toxins in cigarettes, it is suspected to have endocrine-disrupting properties that may increase testosterone levels. The endocrine system is made up of glands and organs including the pituitary gland, thyroid gland, pancreas, ovary, and testis, among others. It uses hormones to control and regulate the body's growth, development, metabolism, reproduction, and mood.
Baby girls exposed to higher levels of the male hormone testosterone in the womb as a result of smoking during pregnancy are at greater risk of abnormal development and long-term adverse effects on their fertility and metabolism, says the research team from the Cigli State Training Hospital in Turkey.
"Baby girls, born to mothers who smoked during pregnancy, show signs of increased testosterone exposure, which may affect their hormone and reproductive function," according to the study presented at the 58th Annual European Society for Paediatric Endocrinology Meeting, in Vienna, Austria, on September 20.
The findings of the study suggest that cigarette is an endocrine disruptor that can "masculinize girls in the womb" and that smoking during pregnancy might damage daughters' future fertility, says the research team.
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Fifty-six female and 64 male newborns from mothers who smoked during pregnancy were included in this study. For their research, the team examined anogenital distance (AGD), which is the distance from the midpoint of the anus to the genitalia. Since it is regulated by testosterone levels during fetal development, AGD is a sensitive marker of testosterone exposure and life-long reproductive health.
The researchers found that the anogenital distance was significantly longer in the baby girls and it correlated with the amount the mothers smoked. There was, however, no effect on the AGD in the boys.
"This significant increase in anogenital distance in girls exposed to maternal smoking may be an indicator of excessive testosterone exposure that poses a risk for short and long-term health problems, including metabolism and fertility. Further investigation is needed to explain the relationship between maternal smoking, increased anogenital distance, and future health issues in girls," says Dr. Deniz Ozalp Kizilay from the Cigli State Training Hospital.
According to the researchers, more studies are needed as the mechanisms behind the potential reproductive problems caused by exposure to cigarette smoke in the womb are not completely understood yet.
"Our results do suggest that girls (whose mothers smoked during pregnancy) have higher testosterone exposure, but not how this relates to reproductive function. More extensive and carefully-designed studies are required to explain this relationship," adds Dr. Kizilay.
Future research by the team will focus on monitoring the same group of girls to understand and assess the long-term effects of exposure to higher testosterone levels caused by smoke exposure and in what ways it could affect their health and fertility.