Foetal Alcohol Syndrome (FAS) is the most severe form of Foetal Alcohol Spectrum Disorders (FASD), caused by prenatal alcohol exposure, a major preventable cause of congenital disability. FASD lack specific prenatal ultrasound signs, making early diagnosis difficult.

To describe prenatal ultrasound findings in pregnancies with reported alcohol use and compare maternal and neonatal characteristics according to the presence of anomalies.

We conducted a retrospective multicentre study in three hospitals from September 2013 to April 2025. All women reporting alcohol use during pregnancy were included. Exposure was classified by quantity (moderate: ≤3 drinks/day or <40 cl/day; excessive: >3 drinks/day or >40 cl/day) and frequency (occasional, often, chronic), based on maternal self-report. Ultrasound scans from all trimesters were reviewed for growth and morphological anomalies. Comparative analyses were performed between women with and without anomalies.

Among 94 pregnancies, 30 (32%) showed ultrasound anomalies. Women with anomalies were older (33.9 vs. 31.7 years, p <0.01), with no differences in BMI, parity, or co-exposures. Occasional alcohol use appeared not associated with anomalies, whereas increasing maternal age (aOR = 1.22; 95% CI [1.09-1.40]) was an independent risk factor. Most anomalies were detected in the second trimester, mainly foetal growth restriction (FGR) and microcephaly. Neonatal abnormalities occurred in 70% of the anomaly group versus 10.9% without anomalies (p < 0.01). Seven neonates (11%) had undiagnosed FGR or microcephaly at birth.

Ultrasound anomalies were found in one-third of alcohol-exposed pregnancies, underscoring the risks of chronic alcohol use.