(1048) Perinatal outcomes in individuals with classic versus mosaic Turner syndrome: a retrospective cohort study

Pregnancy in individuals with Turner syndrome (TS) is associated with an increased risk of adverse pregnancy and maternal outcomes, but most available data are from small case series that do not differentiate between classic and mosaic types. As mosaic TS may be associated with a less severe phenotype, we sought to compare maternal and perinatal outcomes for individuals with classic versus mosaic TS in a large dataset.

Study Design:

This retrospective cohort study used Epic Cosmos, a large, de-identified, national clinical dataset, currently with 300 million patients. Pregnancies with maternal TS identified by ICD-10 codes and delivery outcomes were included. Maternal demographic characteristics and perinatal outcomes within 30 days of delivery were compared for those with classic vs mosaic TS.

Results:

2724 were identified: 1875 with classic TS and 849 with mosaic TS (Table). Those with mosaic TS were older (31.9 vs 30.5y, p< 0.001), more likely to be White (75.9 vs 69.3%, p< 0.001), had a higher prior cesarean delivery rate (29.7 vs 25.5%, p=0.044), and a higher risk of maternal congenital heart disease (2.9 vs 1.3%, p=0.004). Those with classic TS had a higher number of prior live births (1.04 vs 0.86, p< 0.001) but were also more likely to have had a prior fetal demise (10.2 vs 2.9%, p< 0.001). Regarding delivery outcomes, cesarean delivery rate was higher (44.6 vs 38.5%, p=0.005) and birthweight was lower (3088 vs 3159g, p=0.02) in the mosaic TS group; delivery outcomes were otherwise similar. Postpartum aortic dissection was rare in both groups but occurred more frequently in the mosaic TS group (0.59 vs 0.11%, p=0.034). There were no maternal deaths in either group.

Conclusion:

In this large cohort of deliveries complicated by maternal TS, pregnancy outcomes for individuals with classic TS and mosaic TS were overall favorable, although there were some phenotypic and outcome differences between groups. Given limitations in the dataset – including possible inaccurate TS classification and incomplete data capture (including conception method) – these findings should be interpreted with caution.