Findings Highlight Increased Risks in ART Pregnancies

Birth defects are more prevalent in pregnancies conceived through assisted reproductive technology (ART), such as IVF,  with teratogenic medication exposure identified as a key contributing factor. A study published in the Australian and New Zealand Journal of Obstetrics and Gynaecology analyzed over 57,000 pregnancies in Western Australia, uncovering significantly higher exposure rates to medications known to interfere with fetal development in ART pregnancies compared to natural conceptions.

The study revealed that 4.9% of ART pregnancies were exposed to Category D medications during the first trimester, a critical period for organ formation, compared to just 0.6% of naturally conceived pregnancies. In later trimesters, the disparity persisted, with 3.4% of ART pregnancies exposed versus 0.6% of natural conceptions. These findings highlight the potential role of teratogenic medication exposure in the increased prevalence of birth defects observed in ART-conceived children.

Teratogenic Medications and Birth Defects in ART Pregnancies

Category D medications, defined by the Therapeutic Goods Administration (TGA), are drugs showing evidence of fetal risk based on human studies. These drugs are associated with structural abnormalities, including congenital heart defects and neural tube defects, as well as functional impairments.

The study also investigated exposure to Category X medications, which are contraindicated in pregnancy due to their high teratogenic risk. However, exposure to these drugs was less than 0.5% across all pregnancy groups, including ART pregnancies.

ART pregnancies showed the highest rates of exposure to these medications compared to other conception groups, including ovulation induction (OI) pregnancies and untreated subfertility pregnancies. OI pregnancies, for example, had a 2.0% exposure rate in the first trimester, still significantly lower than the 4.9% observed in ART pregnancies.

Factors Contributing to Increased Risk in ART Pregnancies

The study found an apparent disparity in medication exposure between ART pregnancies and natural conceptions. Women undergoing ART often face complex medical regimens that may increase the likelihood of exposure to Category D medications. While the study did not examine the disparity’s specific causes, the elevated exposure rates in ART pregnancies align with broader observations of higher medical intervention in this population.

Birth Defects in ART Pregnancies

The higher rates of exposure to teratogenic medications during critical periods of pregnancy development are a significant concern. These medications can interfere with the delicate organogenesis processes in the first trimester, leading to developmental abnormalities. The increased prevalence of birth defects among ART-conceived children suggests that medication exposure plays a substantial role. However, additional factors, such as maternal age and underlying conditions, may also contribute.

Study Details and Broader Implications

The study in Western Australia analyzed 57,681 pregnancies between 2012 and 2014. Of these, 2,041 were ART pregnancies, 590 were ovulation induction pregnancies, 2,063 were untreated subfertility pregnancies, and 52,987 were naturally conceived. The findings emphasize the need for heightened awareness of the risks associated with medication use during pregnancy, particularly in ART populations and those facing infertility..

The results underscore the importance of carefully evaluating the use of teratogenic medications in pregnancies achieved through ART. While these medications may be necessary in specific contexts, their risks to fetal development must be carefully weighed against their potential benefits.

Reference

Anna Kemp‐Casey, Roger Hart, Elizabeth Milne, Carol Bower, Melanie L. Walls, John L. Yovich, Peter Burton, Yanhe Liu, Hamish Barblett, Michele Hansen. “Are assisted reproductive technology pregnancies more likely to be exposed to teratogenic medication? A whole‐population study.” Australian and New Zealand Journal of Obstetrics and Gynaecology, 2024. DOI: 10.1111/ajo.13911.