Developmental Delays Not Tied to Infertility Treatment

Led by researchers at the National Institutes of Health, the New York State Department of Health, and other institutions, the study found that children conceived using infertility treatments—no matter the type—are no more likely to experience a developmental delay by age 3 than children conceived without this treatment.^1,2

Types of infertility treatment. Published in January issue of JAMA Pediatrics, the Upstate KIDS Study looked prospectively at children born between 2008 and 2010 in New York state (but not NYC). This included 1,800 children born to women who became pregnant following infertility treatment and 4,000 children born to women who had no treatment.

Parents in the treatment group had used drugs to stimulate ovulation (ovulation induction) or had sperm placed into the uterus with a narrow tube (intrauterine insemination) or had one or more of the following assisted reproductive technology (ART) procedures:

• Fertilizing an egg with sperm in a laboratory dish (in vitro fertilization-IVF)
• Implanting a previously fertilized and frozen egg into the uterus (frozen embryo transfer)
• Placing a microscopic hole in the protein covering the embryo (assisted hatching)
• Mixing sperm and egg before placing them in the fallopian tube (gamete intrafallopian transfer)
• Placing a fertilized egg into the fallopian tube (zygote intrafallopian transfer)

Developmental screening. All parents in the study completed the Ages and Stages Questionnaire (ASQ) to screen for developmental disabilities. They completed the questionnaire throughout the first 3 years—at 4, 8, 12, 24, 30, and 36 months. As part of the questionnaire, parents were encouraged to engage in activities with their children, and then answer questions about these 5 areas of development:

• Fine motor skills—such as the ability of older babies to manipulate toys with hands

• Gross motor skills—such as the ability of an older babies to sit up unsupported

• Personal and social functioning—such as the ability of older babies to feed themselves

• Communication—such as the ability of two-year-olds to know names of body parts

• Problem-solving—such as the ability of two-year-olds to sort shapes and colors^3,4

The twin factor. Looking only at children conceived by ART procedures such as IVF, the researchers did find a higher level of delays in at least 1 of the 5 domains of development. The 2 areas with higher rates of delay were those of personal and social functioning and problem-solving ability

However, after a closer look, there was a clear confounder: twin births, which are well-known to affect childhood development and lead to complications in pregnancy and delivery. These children were more likely to fail developmental domains than were single born children (singletons). And, as expected, there were more twins born to parents who had received infertility treatment. Once the researchers adjusted for both birth weight and the higher rate of multiples in the ART group (34 percent) versus the non-treatment group (19 percent), there were no significant differences between the two groups.

There were also no differences in singletons referred for an evaluation—whether in the treatment or non-treatment group. By the same token, among children actually diagnosed with a disability at 3 to 4 years old, there were no significant differences between the treatment and non-treatment groups.

Because some developmental disabilities don’t surface until after age 3, the researchers will continue to follow these children. Although this study is an observational study, which can’t prove cause and effect, it provides a wealth of reassuring data that should have many parents—and prospective parents—breathing a big sigh of relief.

Sources

1. Yeung, EH et al. JAMA Pediatr. 2016. (170). Doi:10.1001/jamapediatrics.2015.4164.
2. NIH: Infertility treatments do not appear to contribute to developmental delays in children.
3. PubMed Health: Infertility treatments ‘not linked’ to developmental delays.
4. CDC: Important Milestones: Your Child at Two Years.

See all articles