Outcomes following the detection of fetal edema in early pregnancy prior to non‐invasive prenatal testing

Abstract

Abstract Objective To investigate the incidence of structural and chromosomal abnormalities in cases of fetal edema on early ultrasound prior to non‐invasive prenatal testing (NIPT). Methods A retrospective study of women undergoing pre‐NIPT ultrasound with fetal crown‐rump length (CRL) of 28 to 44 mm was conducted at a tertiary obstetric ultrasound clinic in Melbourne, Australia. Cases of reported fetal edema were included, and subclassified as isolated nuchal edema (>2.2 mm) or generalized edema/hydrops by two operators blinded to outcomes. Results We identified 104 cases of fetal edema. Nuchal edema and generalized edema were present in 40 (38.5%) and 64 (61.5%) cases, respectively. Relevant chromosomal anomalies were identified in 19.2% (20/104), occurring in 10.0% (4/40) of the nuchal edema and 25.0% (16/64) of the generalized edema/hydrops cases. Structural anomalies with normal karyotype occurred in four (3.8%) additional cases. Miscarriage occurred in four cases (3.8%) and termination of pregnancy in 18 cases (17.3%). Among cases that reached the 11 to 13 +6 weeks ultrasound, the edema resolved in 81.9% and these cases had less adverse outcomes than those with NT≥3.5 mm (10.9% vs 76.5%, P < .001). Conclusions Fetal edema in early pregnancy is associated with a high incidence of structural and/or chromosomal abnormalities; these rates increase with progressive severity.