Female infants born to mothers who smoked cigarettes during pregnancy exhibit signs of increased testosterone exposure, which may affect their hormone and reproductive function, according to a new Turkish study presented at the 58th Annual European Society for Paediatric Endocrinology Meeting.
In addition to the many toxins present in cigarettes, researchers suspect they may also have endocrine-disrupting properties that can increase testosterone levels. The findings show that female fetuses exposed to higher levels of the male hormone testosterone in the womb are at greater risk of abnormal development and this may lead to long-term negative effects on their fertility and metabolism.
Anogenital distance (AGD), the distance from the midpoint of the anus to the genitalia, is regulated by testosterone levels during fetal development, so is a sensitive marker of testosterone exposure and life-long reproductive health.
For the study, Dr. Deniz Ozalp Kizilay and colleagues at Cigli State Training Hospital in Izmir, Turkey, measured the AGD in 56 newborn girls and 64 newborn boys, from mothers who smoked during pregnancy.
AGD was significantly longer in the baby girls and correlated with the amount the mothers smoked. No effect was found on the AGD in the boys.
“This significant increase in AGD 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,” said Kizilay.
“Further investigation is needed to explain the relationship between maternal smoking, increased AGD and future health issues in girls.”
Kizilay added, “The mechanisms behind the potential reproductive problems caused by exposure to cigarette smoke in the womb are not fully understood. Our results do suggest that girls have higher testosterone exposure but not how this relates to reproductive function. More extensive and carefully designed studies are required to explain this relationship.”
The research team now plans to investigate the long-term effects of exposure to higher testosterone levels caused by smoke exposure in the same group of baby girls, to assess how this may affect their future health and fertility.
“To our knowledge this is the first time that the unfavorable effects of prenatal smoke exposure on AGD, as a marker of testosterone exposure, has been demonstrated in female newborns. These findings are a valuable contribution to our better understanding of the intergenerational effects of maternal smoking,” said Kizilay.