Chorionic Villi Sampling among Early and Late Gestational Age: Does Timing Affect Yield and Outcomes?

Area of Science:

• Prenatal Diagnostics
• Genetics
• Obstetrics

Background:

• Chorionic villus sampling (CVS) is a key prenatal diagnostic tool for genetic abnormalities.
• Typically performed between 10 0/7 and 13 6/7 weeks, with most providers opting for later timing.
• This study investigates the feasibility and outcomes of CVS performed outside this conventional window.

Purpose of the Study:

• To evaluate the feasibility of chorionic villus sampling (CVS) at varying gestational ages.
• To compare chorionic villi (CV) yield and procedural outcomes for early, typical, and late CVS procedures.
• To assess the diagnostic adequacy and safety of CVS performed outside the standard gestational window.

Main Methods:

• A multicenter retrospective study of 719 patients undergoing CVS.
• Patients were categorized into early (10 0/7–10 6/7 weeks), typical (11 0/7–13 6/7 weeks), and late (≥14 0/7 weeks) groups.
• Primary outcome was median CV weight; secondary outcomes included culture need, microarray time, and complication rates.

Main Results:

• 89% of all procedures yielded adequate tissue (≥5 mg), with no significant difference in median villi weight across groups.
• Early CVS was more common in patients with lower BMI, prior affected pregnancies, and performed transvaginally.
• Microarray results were fastest in the typical group, with no significant differences in other secondary outcomes or complication rates.

Conclusions:

• CVS performed before 11 weeks and after 14 weeks is technically feasible and diagnostically adequate.
• These findings support the use of early CVS for cytogenetic testing in early pregnancy loss.
• Further prospective studies are needed to refine optimal CVS timing recommendations.