NEW YORK (Reuters Health) - Babies conceived via fertility treatment might be somewhat smaller at birth than newborns conceived naturally, a new study suggests.
In a study of 1,700 women who gave birth to one child each, researchers found that babies born to women with fertility problems weighed a little less—about a third of a pound, on average.
They were also at somewhat greater risk of low birthweight (less than 5.5 pounds).
The reasons are not fully clear, the researchers say. But they believe that the underlying fertility problems may play a bigger role than the treatments themselves.
Couples who successfully undergo fertility treatment, including fertility drugs and in vitro fertilization (IVF), often end up with twins or more. But research has suggested that even when parents have a single child, called a singleton, their babies tend to be smaller than newborns conceived naturally.
"But it's been hard to tease out, is it the infertility or the technology used to treat it?" said Dr. Amber R. Cooper, an assistant professor of obstetrics and gynecology at Washington University in St. Louis who led the new study.
So Cooper's team looked at records for 461 women who came to their center with fertility problems over 10 years and ultimately had a baby. More than half underwent IVF, while 106 were treated with fertility drugs, and 104 eventually became pregnant on their own.
Those women were compared with 1,246 fertile women who gave birth during the same time period.
Overall, babies born to women with fertility problems were smaller. But there was no difference in average birthweight between women who underwent IVF and infertile women who eventually had a baby without medical help.
The biggest gap was seen in the group of women who'd been treated with fertility drugs, which spur ovulation: Their newborns were about a half-pound lighter compared with fertile mothers.Possible Causes for the Lower Birthweight - Page 2