PREGNANCY OUTCOMES AFTER PGT-A BY RACE: MISCARRIAGE, LOW BIRTHWEIGHT, AND PRETERM BIRTH

Abstract

To evaluate the associations between race, PGT-A use, and rates of miscarriage, low birthweight, and preterm birth. This was a retrospective cohort study using national Society for Assisted Reproductive Technology (SART) data from 2014-2016. Autologous first embryo transfers in women 18-50 years-old were included. Embryo transfer type was categorized as PGT-A tested, fresh untested, and thawed untested. Only cycles resulting in singleton gestations were included for analyses on preterm birth and low birthweight. Low birthweight was defined as <2,500 grams. Age groups were defined as: 18-34, 35-37, 38-40, 41-50 yrs. Of the 110,843 first embryo transfers, 64,331 (58%) resulted in a clinical pregnancy and 53,880 (49%) resulted in a live birth of at least one infant. Miscarriage rate was significantly lower from cycles using PGT-A (13.5%) compared to both fresh (14.7%) and frozen (17.1%) untested embryos (p<0.0001). African American women had the highest miscarriage rates regardless of PGT-A use. Whereas white women had a 13.5% rate of miscarriage after PGT-A, African American women had a 22.4% rate (p<0.0001). Hispanic women had a slightly higher rate of miscarriage (16.9%), but this difference was not statistically significant. Among all cycles, miscarriage rates increased with increasing age, but this was less pronounced with PGT-A use. In multivariate regression for PGT-A cycles, only the oldest age group (41-50) had a statistically significant increased risk of miscarriage compared to the youngest group (OR 1.25; 95% CI 1.06-1.48, p=0.009). African American women had 80% greater odds of miscarriage (OR 1.80; 95% CI 1.34-2.42, p=0.0001) than white women. Among 42,811 singleton live births, preterm birth was lower for cycles after PGT-A (16.6%) than for either fresh (18.3%) or frozen (17.4%) untested embryo transfers (p=0.01). Among women using PGT-A, African American women had the highest rate of preterm birth (24%), followed by Hispanic women (23%). Cycles after PGT-A use were less likely to have a low birthweight infant (6.6%) than either fresh (9.8%) or frozen (7.8%) untested cycles (p<0.001). Among cycles after PGT-A use, African American women had the highest rate of low birthweight infants (13%), over twice that of white women (5.9%) (p<0.001). PGT-A use is associated with reduced rates of miscarriage, preterm birth, and low birthweight infants. However, African American women using this technology still had significantly higher rates of these pregnancy outcomes. Limitations of this study include the fact that approximately 40% of women had unknown race; it is unknown what proportion of prematurity was iatrogenic; and that medical comorbidities predisposing to prematurity and low birthweight are unknown.