Laterality Spectrum Disorders in the Prenatal Era: Outcomes Across the Severity Spectrum and Associations with Pregestational Diabetes

Objective: This study aimed to describe severity-stratified early outcomes in pregnancies with prenatally suspected laterality spectrum disorders (LSD), defined as abnormalities of left-right body patterning affecting thoracoabdominal situs and associated cardiovascular and visceral structures, and to explore phenotype patterns associated with pregestational diabetes mellitus (PDM). Study Design: Retrospective cohort study of pregnancies evaluated at a tertiary fetal care and fetal cardiology referral center (2010-2026). LSD subtype was assigned using a prespecified operational framework. Cardiac severity was classified as major versus nonmajor congenital heart disease (CHD). Outcomes included termination, intrauterine fetal demise (IUFD), neonatal survival (≤28 days), infant survival (28 days-1 year), cardiac surgery, and gastrointestinal morbidity. Results: = 33), neonatal survival was 30/33 (90.9%) and infant survival among neonatal survivors with available follow-up was 20/27 (74.1%). Cardiac surgery occurred in 22/62 (35.5%) and was more common in major versus nonmajor CHD (63.6 vs. 3.4%). Intestinal malrotation occurred in 18/62 (29.0%). Abdominal situs inversus was more frequent in PDM pregnancies (37.5 vs. 8.1%). Conclusion: In LSD, major CHD drives pregnancy termination, surgical intervention, and early mortality concentrated during infancy. PDM was associated with a higher frequency of abdominal situs phenotypes, supporting deliberate postnatal gastrointestinal surveillance planning. Key Points: · In LSD, infant outcomes vary with CHD severity.. · Major CHD drives termination/surgery.. · PDM occurs across the LSD spectrum..