Developmental delays are no more likely to occur in children conceived through infertility treatments than those conceived without treatment, according to new data published in JAMA Pediatrics.
“When we began our study, there was little research on the potential effects of conception via fertility treatments on U.S. children,” study researcher Edwina Yeung, PhD, an investigator in the Division of Intramural Population Health Research at National Institute of Health’s Eunice Kennedy Shriver National Institute of Child Health and Human Development, said in a press release. “Our results provide reassurance to the thousands of couples who have relied on these treatments to establish their families.”
The prospective cohort study included infants born between 2008 and 2010 in New York state, excluding New York City, whose parents completed developmental screening instruments through age 36 months.
Of 4989 mothers, 4824 completed at least 1 developmental screening instrument for 5481 children, including 1830 conceived via infertility treatment and 2074 twins.
A total of 1422 mothers (mean age, 34.1 years) underwent infertility treatment, the researchers reported.
The mothers identified the type of infertility treatment that they received on a questionnaire 4 months after giving birth. These treatments included assisted reproductive technology (ART) such as in vitro fertilization (IVF), frozen embryo transfer, assisted hatching, gamete intra-fallopian transfer, zygote intra-fallopian transfer, ovulation induction, and intrauterine insemination.
Children were also screened for developmental disabilities at ages 4 to 6, 8, 12, 18, 24, and 36 months using a questionnaire that covered 5 main developmental domains: fine motor skills, gross motor skills, communication, personal and social functioning, and problem solving ability.
Results revealed no association between infertility treatment and children’s risk for failing any developmental domain (adjusted odds ratio [OR]=1.33; 95% CI, 0.94-1.89).
The researchers did note an association between ART and increased risk for failing any 1 of the 5 domains, particularly the personal and social and problem solving domains, but only when singletons and twins were analyzed together (adjusted OR=1.81; 95% CI, 1.21-2.72). Twins were more likely to fail a domain than singletons, the researchers noted. Because the percentage of twins was higher in the ART group vs the non-treatment group (34% vs 19%), they identified no significant difference between the ART group and non-treatment group in failing any of the 5 domains.
The relationship between ART and risk for developmental delay was further attenuated after adjustment for birth weight (adjusted OR=1.26; 95% CI, 0.82-1.93).
When stratified by plurality, treatment type did not appear to be significantly linked to failing any developmental domain for ovulation induction/intrauterine insemination (adjusted OR=1.00; 95% CI, 0.57-1.77 for singletons and adjusted OR=1.30; 95% CI, 0.76-2.21 for twins) or ART (adjusted OR=1.38; 95% CI, 0.78-2.43 for singletons and adjusted OR=1.58; 95% CI, 0.94-2.65 for twins).
Furthermore, results revealed no differences in the percentage of singleton children in the 2 groups who were referred for evaluation by developmental specialists (21.2% vs 20.7%). There were also no significant differences between the treatment and non-treatment groups among those diagnosed with a disability from ages 3 to 4 (13% vs 18%).
“We found no evidence suggesting that children’s development through age 3 years — using a standardized parental rating instrument and augmented by registry linkage for developmental services — is associated with any type of infertility treatment in comparison with children conceived without such treatments after accounting for plurality,” the researchers concluded.
“The elevated probability of delay associated with multiple births remains a risk to be weighed given the higher twinning rate after use of ART. Continued follow-up of children conceived by infertility treatment is needed to ensure the absence of later-onset conditions.”
The researchers plan to continue to evaluate the children periodically until age 8.