Children born from in vitro fertilization (IVF) treatments have shown a higher risk of developmental problems, but what is responsible for the heightened risk?
Low birth weight, premature birth and minor problems with brain development have all been correlated with fertility treatments, which include IVF as well as sophisticated insemination techniques. While it’s possible that the treatments themselves, which require manipulation of the egg, sperm and embryo outside of the woman’s body, could be contributing to changes in development, it’s also logical that the infertility that required the procedures in the first place might also be playing a role. And in the latest study investigating the association, published online in the journal Archives of Disease in Childhood, researchers report that the latter may be largely responsible for the neurological differences documented among children born via fertility treatments.
The new study is very small, involving just 209 children who were born to parents who struggled to get pregnant. The findings, however, support previous data that found that techniques associated with IVF were not lniked with increased risk of neurological issues among children at age two who were born using these treatments.
In the current study, the researchers focused on a group of couples enrolled in a study of assisted reproductive techniques who were considered subfertile, or unable to conceive after 12 months of unprotected intercourse. The parents took anywhere from 1.6 years to a little over 13 years to get pregnant, producing 209 children. When they reached age two, the children were evaluated for mild neurological and developmental problems, including movement issues, posture, muscle tone and hand-eye coordination. Seventeen of the toddlers showed minor neurological problems, and these children were more likely to be born of parents who took the longest to conceive. The median time to pregnancy for couples whose children did not show neurological issues was 2.8 years, while it those whose children did show minor problems took 4.1 years to conceive. Taking a longer time to get pregnant was associated with a 30% greater risk of having a child with mild neurological issues — even when the researchers accounted for other factors like parents’ age and education, which can also affect risk of such developmental abnormalities.
The results imply that factors linked to poor fertility, which can contribute to taking longer to conceive, were playing a larger role in the children’s poor development than the fertility treatments themselves. The authors also stress that the development issues noted in the study are not debilitating, but minor abnormalities that probably don’t affect overall behavior or development.
“Suboptimal neurological condition does not imply overt problems in daily life. It does, however, indicate an increased vulnerability for developmental problems such as learning and behavior problems. This means that our findings do not have significance on the level of the individual child, but that they do have significance for the population at large,” says study author Mijna Hadders-Algra, a professor of developmental neurology at the Beatrix Children’s Hospital at the University of Groningen Medical Center in The Netherlands.
Hadders-Algra hopes the results raise awareness that prolonged time to pregnancy is associated with a less optimal brain condition in the baby, and that researchers and fertility specialists keep this in mind as they help parents to conceive. “Prolonged time to pregnancy may be prevented by reduction of maternal age at child conception. This is an issue with strong political and social consequences,” she says. “For instance, in the Netherlands, the age at which women get their first child steadily increases. One could say: a smart woman gets her pregnancy in time.”
Results from studies such as the current one should inform reproductive health policy, she says. In the United Kingdom, for example, the National Health Service revised its guidelines in February to allow women to start IVF treatments earlier, after two years of failed attempts to get pregnant, rather than three, but extended the upper age limit for women from 39 years to 42 years. As more studies such as Hadders-Algra’s become available to better inform doctors and policy makers, such guidelines can become better suited to reflect the risks and benefits of the latest assisted reproductive techniques, for both the parents and the child.