Severe maternal morbidity risk increases with IVF use, older age

Key takeaways:

• Severe maternal morbidity prevalence was higher for women who used IVF vs. nonusers.
• Risk for severe maternal morbidity was lower for women who used IVF at older vs. younger ages.

DENVER — IVF and older maternal age were both independently associated with increased risk for severe maternal morbidity, and the risk weakened for women who utilized IVF at older ages, researchers reported.

“Despite their clear independent associations, little is known about the intersection of IVF and maternal age and this impact on severe maternal morbidity,” Sara E.K. Phillips, MD, MPH, resident physician in the department of obstetrics and gynecology at Oregon Health & Science University, said during a presentation at the ASRM Scientific Congress & Expo.

Phillips and colleagues conducted a retrospective cohort study utilizing data from 1,728,478 singleton pregnancies delivered 23 to 42 weeks’ gestation from 2016 to 2020 in California. Researchers assessed risk for severe maternal morbidity with IVF conceptions across all age groups (20-29 years, 30-34 years, 35-39 years, 40-44 years, 45 years).

Overall, 0.98% of pregnancies were conceived with IVF. Most IVF conceptions were in women aged 35 to 39 years (39.5%), 30 to 34 years (25.7%) and 40 to 44 years (21.9%); 7.4% were in women aged 45 years and older. Most spontaneous conceptions were in women aged 20 to 29 years (42.8%) and 30 to 34 years (30.6%). Compared with spontaneous conception, women who utilized IVF had a higher prevalence of severe maternal morbidity (1.3% vs. 3.04%; P < .001), Phillips said during the presentation. Researchers observed significantly higher severe maternal morbidity risk for pregnancies conceived with IVF vs. spontaneous conception after adjusting for maternal race/ethnicity, education, prepregnancy BMI, insurance status, parity, gestational age, smoking status and delivery year (adjusted RR = 2.16; 95% CI, 1.97-2.35), Phillips said.

Among pregnancies conceived with IVF, women aged 20 to 29 years had the greatest relative severe maternal morbidity risk (aRR = 2.05; 95% CI, 1.4-2.99), with a trend toward decreasing risk in older age groups of 30 to 34 years (aRR = 1.87; 95% CI, 1.55-2.25), 35 to 39 years (aRR = 1.92; 95% CI, 1.66-2.22), 40 to 44 years (aRR = 1.49; 95% CI, 1.22-1.82) and 45 years and older (aRR = 1.28; 95% CI, 0.91-1.79).

“Our analysis suggests that these effects may not necessarily impact one another,” Phillips said. “Although there’s a global risk of adverse maternal outcomes in patients who require IVF, the relative risk associated with IVF appears dampened at older ages.”

The researchers concluded that preconception optimization is key for women of all ages utilizing IVF.