Researchers studied 49 women with OTCD who had a total of 109 pregnancies. The goal was to understand how pregnancy affects women with this condition, especially comparing those who have symptoms to those who do not. The study included women from a large U.S. and international research network and collected data both before and after enrollment in a long-term study. The team looked at things like episodes of high ammonia (hyperammonemia), ICU admissions, and pregnancy outcomes. This is the largest study so far to look at pregnancy safety in OTCD carriers.
Key Takeaways
Less Risk for Asymptomatic Women: Women without symptoms had no episodes of high ammonia during pregnancy or postpartum. They also had more living children on average (2.04) compared to symptomatic women (1.29).
Higher Risk for Symptomatic Women: Among women with symptoms, 5 out of 21 pregnancies (24%) had metabolic problems, all involving high ammonia. One woman needed ICU care, but there were no deaths.
Overall Outcomes Were Good: Across all pregnancies, 83% resulted in live births, with miscarriage (10%) and termination (6%) rates similar between groups. No cases of coma, dialysis, or maternal death were reported.
Routine Risk Factors Did Not Explain Differences: Conditions like preeclampsia, gestational diabetes, or advanced maternal age were not more common in symptomatic women, so the extra risk seems linked to OTCD itself.
Close Monitoring Is Key: All women in this study were followed by metabolic specialists, which may have helped prevent serious complications. Past reports show much higher risks when OTCD is undiagnosed or unmanaged.
Why This Matters
This research helps clarify that pregnancy can be safe for women with OTCD, especially if they have no symptoms and receive specialized care. For those with symptoms, extra monitoring and planning are important to reduce risks.
Breilyn MS, Simpson K, Elsbecker SA, Barber JR, Bryan K, Berry SA. Maternal Health Outcomes in Ornithine Transcarbamylase Deficiency: A Comparative Analysis of Pregnancies in Symptomatic and Asymptomatic Heterozygotes. Mol Genet Metab. 2025 April;144(4):109083. doi: 10.1016/j.ymgme.2025.109083
