[Fetal abdominal cysts at the first trimester scan]

Area of Science:

• Perinatology
• Fetal Medicine
• Diagnostic Ultrasound

Background:

• Abdominal cysts detected during the first trimester of pregnancy are uncommon.
• The long-term outcomes for these fetal abdominal cysts are not well-established.

Purpose of the Study:

• To investigate the outcomes of abdominal cysts identified during first-trimester ultrasound scans.
• To establish the prognosis associated with these rare fetal findings.

Main Methods:

• A prospective observational study was conducted over 24 months by the French College of Fetal Ultrasound.
• Data included ultrasound images, expert reports, and pregnancy outcomes for 10 cases of first-trimester abdominal cysts (excluding megacystis).

Main Results:

• Two-thirds of the abdominal cysts (6/10) resolved by 18 weeks of gestation (WG), with generally good postnatal outcomes.
• Anechoic cysts were associated with normal infant examinations.
• Non-resolving or complex (hyperechoic/mixed) cysts had poor outcomes, including terminations due to suspected cloacal dysgenesis.

Conclusions:

• Abdominal cysts are rare in early pregnancy but often resolve spontaneously, leading to favorable outcomes.
• Persistent or complex cysts necessitate follow-up ultrasound examinations at 18 and 22 weeks of gestation for risk assessment and management planning.