How often do we identify fetal abnormalities during routine third‐trimester ultrasound? A systematic review and meta‐analysis

Abstract

Background Routine third-trimester ultrasound is frequently offered to pregnant women to identify fetuses with abnormal growth. Infrequently, a congenital anomaly is incidentally detected. Objective To establish the prevalence and type of fetal anomalies detected during routine third-trimester scans using a systematic review and meta-analysis. Search strategy Electronic databases (MEDLINE, Embase and the Cochrane library) from inception until August 2019. Selection criteria Population-based studies (randomised control trials, prospective and retrospective cohorts) reporting abnormalities detected at the routine third-trimester ultrasound performed in unselected populations with prior screening. Case reports, case series, case-control studies and reviews without original data were excluded. Data collection and analysis Prevalence and type of anomalies detected in the third trimester. We calculated pooled prevalence as the number of anomalies per 1000 scans with 95% confidence intervals. Publication bias was assessed. Main results The literature search identified 9594 citations: 13 studies were eligible representing 141 717 women; 643 were diagnosed with an unexpected abnormality. The pooled prevalence of a new abnormality diagnosed was 3.68 per 1000 women scanned (95% CI 2.72-4.78). The largest groups of abnormalities were urogenital (55%), central nervous system abnormalities (18%) and cardiac abnormalities (14%). Conclusion Combining data from 13 studies and over 140 000 women, we show that during routine third-trimester ultrasound, an incidental fetal anomaly will be found in about 1 in 300 scanned women. This information should be taken into account when taking consent from women for third-trimester ultrasound and when designing and assessing cost of third-trimester ultrasound screening programmes.

Associations between the Maternal Exposome and Metabolome during Pregnancy

“…Meanwhile, in the third trimester, a number of maternal ( Salonen Ros et al. 2001 ) and fetal abnormalities ( Drukker et al. 2021 ) related to pregnancy become apparent.…”

Prenatal Diagnosis of Snijders Blok-Campeau Syndrome in a Fetus with Macrocephaly

“…The performance of routine anomaly US scans during the 3rd trimester has been and is still a matter of controversy and as such has been implemented only in few countries [10]. In Israel, this type of examination is gaining rapid popularity although it has not been adopted as part of the routine prenatal care.…”

Authors’ reply re: How often do we identify fetal abnormalities during routine third‐trimester ultrasound? A systematic review and meta‐analysis

“…We appreciate the letter by Claudia Massarotti et al; 1 their observations and the results of our systematic review and meta‐analysis 2 are relevant to the health care of pregnant women and their babies worldwide.…”

“…As discussed by Massarotti et al, 1 there has been limited focus on the evaluation of fetal abnormalities in the third trimester. While our systematic review and meta‐analysis helps to us to understand the clinical effectiveness of such third‐trimester screening, 2 it is important to highlight that the study was not designed to answer whether routine third‐trimester ultrasound should be undertaken for the detection of fetal anomalies. Despite the advantages of detection of fetal abnormalities even late in pregnancy outlined by Massarotti et al, 1 a recommendation for implementing such routine screening should only be made after an assessment of screening performance (including the likelihood and implication of false‐positive diagnoses) and cost‐effectiveness analysis.…”