Evaluation of the effect of SARS-CoV-2 infection on Doppler ultrasound and placental findings of pregnant women: a systematic review and meta-analysis.

Purpose: Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) can infect the human placenta and has been shown to have an adverse effect on Doppler ultrasound parameters and placental features. However, the specific effects of the SAS-CoV-2 infection on the fetal-placental unit in pregnant women remain unclear. The aim of this systematic review and meta-analysis was to evaluate the impact of SARS-CoV-2 infection on Doppler ultrasound and placental findings in pregnant women.

Methods: A systematic search was conducted using four electronic databases (PubMed, Embase, Scopus, and Cochrane Library) to select publications published in peer-reviewed journals written in English. Odds ratios (ORs) were calculated, along with their 95% confidence intervals (CIs). Heterogeneity was assessed using Cochrane Q and I2 statistics and the appropriate P-value. The analysis used RevMan 5.3.

Results: This meta-analysis included 1,210 pregnant women from 10 case-control studies. SARS-CoV-2-infected pregnant women exhibited higher likelihoods of placental abnormalities (OR, 2.62; 95% CI, 1.66 to 4.13), aberrant Doppler values (OR, 1.95; 95% CI, 1.16 to 3.27), an abnormal cerebroplacental ratio (OR, 2.68; 95% CI, 1.52 to 4.75), altered fetoplacental circulation (OR, 1.56; 95% CI, 1.07 to 2.28), and increased placental thickness and placental venous lakes (OR, 1.85; 95% CI, 1.25 to 2.72).

Conclusion: According to this meta-analysis, pregnant women infected with SARS-CoV-2 are more likely to experience altered Doppler ultrasonography parameters and placental abnormalities, including increased placental thickness, placental venous lakes, altered fetoplacental circulation, and cerebroplacental ratio. However, the limited number of case-control studies requires larger sample sizes to validate and enhance the evidence.