Gestational syphilis and stillbirth in the Americas: a systematic review and meta-analysis

To perform a systematic review and meta-analysis of reported estimates of the association between gestational syphilis (GS) and stillbirth in the Americas region.

Cochrane Library, Embase, LILACS, MEDLINE/PubMed, PLOS, and ScienceDirect were searched for original research studies quantifying the relationship between GS and stillbirth in the region. A final sample of eight studies was selected. A cumulative meta-analysis plus four subgroup meta-analyses of study data on the association between maternal syphilis during pregnancy and stillbirth were conducted. The four meta-analyses were based on 1) definition of cases and the control; 2) syphilis treatment (presence or absence, effective or ineffective); 3) definition of stillbirth as "showing no signs of life at birth"; and 4) definition of stillbirth based on low birth weight and gestational age. Random-effects metaanalyses were used to calculate pooled estimates of stillbirth with exposure to GS, and each subgroup analysis was tested for heterogeneity.

Women with GS had increased odds of stillbirth (pooled odds ratio (OR): 6.87; 95% confidence interval: 2.93, 16.08). There was considerable heterogeneity across the eight studies (percentage of variance (I²) = 95). The funnel plot was not statistically significant, pointing to a lack of publication bias. Increased odds of stillbirth among pregnant women with syphilis were also seen in all four subgroup meta-analyses.

GS is a major contributing factor for stillbirths in the Americas. Interventions targeting GS are highly cost-effective and, along with high-quality point-of-care testing, should be implemented across the region to help reach the goal of eliminating congenital syphilis.