First-Trimester Ultrasounds Detect 40 Percent of Anomalies

WEDNESDAY, Nov. 26, 2025 (HealthDay News) — Routine first-trimester ultrasounds lead to earlier detection of fetal anomalies, according to a study published online Nov. 25 in PLOS Medicine.

Jehan N. Karim, from the University of Oxford in the United Kingdom, and colleagues examined if different policies of fetal anatomical ultrasound practice have an impact on earlier diagnosis of major fetal anomalies. The analysis included a national survey of first-trimester ultrasound protocols by all National Health Service (NHS) maternity units in England with congenital anomaly registration data from the National Congenital Anomaly and Rare Disease Registration Service for approximately 1.03 million pregnancies between April 2017 and March 2019.

The researchers found that 5,895 fetuses were affected by one of the anomalies of interest. Three-quarters of NHS trusts regularly conducted first-trimester anatomical assessment, though the scope varied. Approximately one-third of anomalies (32.7 percent) were detected before 16 weeks, with detection rates increasing stepwise by protocol detail: 27.7 percent in trusts with no protocol to 40.4 percent in those with extended protocols. Regardless of protocol, conditions such as acrania, exomphalos, and gastroschisis were commonly detected early. Detection was significantly higher for anomalies such as spina bifida, limb reduction defects, and major cardiac malformations in centers employing detailed first-trimester anatomical protocols.

“With advancing ultrasound technology much earlier detection of serious fetal conditions is now feasible; our guidance must catch up to these developments so families can benefit,” Karim said in a statement.

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