Late Amniocentesis is Safe With High Diagnostic Value

TOPLINE:

Late amniocentesis demonstrates a 22.9% overall genetic diagnostic yield, with 2.4 times higher yield for fetuses with multiple organ system anomalies (36.4%) vs single organ system anomalies (15.3%). The procedure shows a low 1.2% complication rate, with delivery occurring at a median of 38 weeks 3 days gestation.

METHODOLOGY:

• Researchers established a collaborative network including nine international sites: Baylor College of Medicine, Columbia University Irving Medical Center, Children’s Hospital of Philadelphia, Johns Hopkins University, The University of North Carolina at Chapel Hill, University of California San Francisco, Sheba Medical Center in Israel, The National Maternity Hospital, and Justus-Liebig University Giessen.
• Medical records from pregnant individuals with singleton or twin pregnancies who underwent amniocentesis between 24 weeks 0 days and 36 weeks 6 days for diagnostic testing were analyzed.
• Analysis focused primarily on prenatal genetic testing cases, with a small subset evaluated for fetal infection based on maternal serology results or sonographic findings.
• Exclusion criteria encompassed higher-order multiple gestations, unavailable pregnancy outcomes, amniocentesis for obstetric indications, and cases involving other invasive procedures during pregnancy.

TAKEAWAY:

• Late amniocentesis demonstrated an overall genetic diagnostic yield of 22.9%, with a 2.4-fold higher yield for fetuses with multiple organ system anomalies (36.4%) than for fetuses with single organ system anomalies (15.3%).
• Delivery occurred at a median gestational age of 38 weeks 3 days, with an average interval of 59 days between amniocentesis and birth.
• The postprocedure complication rate was 1.2%, with no significant difference in preterm delivery rates between early (24-28 weeks) and later (28-32 weeks) gestation groups.
• According to the authors, the timing of amniocentesis after 24 weeks did not impact preterm birth outcomes, with comparable spontaneous preterm delivery rates across all gestational age groups (24-27 weeks, 9.3%; 28-31 weeks, 10.8%; 32-36 weeks, 5.8%; P = .26).

IN PRACTICE:

“Together, these multicenter data show that late amniocentesis performed for pregnancies with fetal structural anomalies or other findings suggestive of genetic conditions or fetal infection has a high diagnostic yield with an acceptable safety profile, and that adverse outcomes are primarily driven by the complexity of the fetal anomalies rather than by procedure-related complications,” the authors of the study wrote.

SOURCE:

This study was led by Ignatia B. Van Den Veyver, MD, Baylor College of Medicine in Houston. It was published online in American Journal of Obstetrics & Gynecology.

LIMITATIONS:

The retrospective design limited the ability to capture data on all late amniocenteses performed at each site during the study period. Information about pregnant individuals who declined the procedure and their reasons for doing so was not available. The 11-year study duration (2011-2022) meant that not all participants received the same level of diagnostic examination, as genetic testing capabilities evolved significantly during this period. Different legal frameworks for pregnancy termination across countries and states may have influenced participation rates. The study’s focus on referral centers potentially introduced selection bias, as these facilities typically handle more complex cases.

DISCLOSURES:

The authors reported no conflicts of interest. The study received research support through multiple National Institutes of Health awards, including P50HD103555 from the Eunice Kennedy Shriver National Institute of Child Health & Human Development, T32 GM07526 from the National Institute for General Medical Sciences, RO1HD105868 from the Eunice Kennedy Shriver National Institute of Child Health & Human Development, and 5K23DK119949 from the National Institute of Diabetes and Digestive and Kidney Diseases. The content does not necessarily represent the official views of the National Institutes of Health.

This article was created using several editorial tools, including AI, as part of the process. Human editors reviewed this content before publication.