Children conceived via infertility treatments are no more likely to have a developmental delay than children conceived without such treatments, according to a recent study.
Investigators at the National Institutes of Health, the New York State Department of Health and other institutions published the research Jan. 4 on the website of JAMA Pediatrics. The findings might help to allay longstanding concerns that conception after infertility treatment could affect the embryo at a sensitive stage and result in lifelong disability, according to a news release.
The authors found no differences in developmental assessment scores of more than 1,800 children born to women who became pregnant after receiving infertility treatment and those of more than 4,000 children born to women who did not undergo such treatment.
“When we began our study, there was little research on the potential effects of conception via fertility treatments on U.S. children,” Edwina Yeung, PhD, an investigator in the Division of Intramural Population Health Research at NIH’s Eunice Kennedy Shriver National Institute of Child Health and Human Development, said in the release. “Our results provide reassurance to the thousands of couples who have relied on these treatments to establish their families.”
Also taking part in the study were researchers from the University at Albany, N.Y.; the New York State Department of Health, also in Albany; and CapitalCare Pediatrics in Troy, N.Y. The Upstate KIDS study enrolled infants born to women in New York State (except for New York City) from 2008-10. Parents of infants whose birth certificates indicated infertility treatment were invited to enroll their children in the study, as were all parents of twins and other multiples. The researchers also recruited roughly three times as many singletons not conceived via infertility treatment.
Four months after giving birth, the mothers indicated on a questionnaire the type of infertility treatment they received:
- Zygote intrafallopian transfer — placement of fertilized egg (zygote) into the fallopian tube.
- Gamete intrafallopian transfer — mixing of sperm and egg before placing them in the fallopian tube.
- Assisted hatching — placement of a microscopic hole in the zona pellicuda, the protein covering of the embryo.
- Frozen embryo transfer — implantation of an embryo that had been previously frozen.
- In vitro fertilization — fertilization in a laboratory dish, after eggs and sperm are taken from the couple.
- Ovulation induction — treatment with drugs that stimulate ovulation.
- Intrauterine insemination — placement of the sperm directly in the uterus via a narrow tube.
Parents also completed a questionnaire to screen children for developmental disabilities at numerous intervals throughout their children’s first three years of life: at 4-6, 8, 12, 18, 24 and 36 months of age. The questionnaire covered five main developmental areas, or domains: fine motor skills, gross motor skills, communication, personal and social functioning, and problem-solving ability. Overall, findings showed children conceived via fertility treatments scored similarly to other children on the five areas covered in the developmental assessments.
When the researchers considered only children conceived through ART, results showed they were at increased risk for failing any one of the five domains, with the greatest likelihood of failing the personal-social and problem-solving domains.
However, researchers found twins were more likely to fail a domain than were singletons. So, when the team compensated for the greater percentage of twins in the ART group than in the nontreatment group (34% vs. 19%), they found no significant difference between the ART group and the nontreatment group in failing any of the five domains.
Similarly, the researchers found no statistically significant differences in the percentage of singleton children in the two groups who were referred for evaluation by developmental specialists (21.2% vs. 20.7%). Of the children diagnosed with a disability at ages 3-4, no significant difference was found between the treatment and nontreatment groups: 13%, compared with 18%.
Because it is not always possible to diagnose some forms of developmental disability by age 3, the study authors will continue to evaluate the children periodically until they reach age 8.