Risk of Stillbirth for Fetuses With Specific Birth Defects.

Area of Science:

• Perinatology
• Medical Genetics
• Public Health

Background:

• Stillbirth, defined as fetal death at 20 weeks gestation or more, poses a significant concern in prenatal care.
• Birth defects are a leading cause of infant mortality and morbidity.
• Accurate risk assessment for stillbirth associated with specific congenital anomalies is crucial for clinical management and parental counseling.

Purpose of the Study:

• To estimate the stillbirth risk associated with specific major birth defects.
• To differentiate risks for isolated versus non-isolated birth defects.
• To quantify the potential bias in stillbirth risk estimates due to elective pregnancy terminations.

Main Methods:

• Retrospective cohort study of neonates and fetuses with selected major birth defects from nine U.S. states.
• Medical records were reviewed by clinical geneticists for defect confirmation and classification.
• Stillbirth risks were calculated overall and for isolated defects, with bias analysis for elective terminations.

Main Results:

• Stillbirth risks varied widely, from 11/1,000 for bladder exstrophy to 490/1,000 for limb-body-wall complex.
• Elevated risks were noted for isolated oral clefts (10/1,000) and limb defects (11-110/1,000).
• Failure to account for terminations could lead to underestimation of stillbirth risks for conditions like spina bifida (24/1,000).

Conclusions:

• Birth defect-specific stillbirth risks are substantially higher than the general U.S. rate (6/1,000).
• Even isolated birth defects carry increased stillbirth risks, necessitating careful evaluation.
• Elective terminations can significantly bias stillbirth risk estimates, highlighting the need for comprehensive data analysis in prenatal diagnosis counseling.