A Meta Analysis on Risks of Adverse Pregnancy Outcomes in Toxoplasma gondii Infection

Objective: Quantified risks of congenital Toxoplasma gondii infection and abnormal pregnancy outcomes following primary maternal infection were evaluated with meta-analysis based on published studies. Methods: The related literatures were searched in multiple literature databases regardless of languages. Odds ratio (OR) and 95% confidence interval (CI) were used to evaluate the risks of vertical transmission of Toxoplasma gondii and abnormal pregnancy outcomes following primary maternal infection with meta-analysis. Results: 53 of the 2632 searched literatures were included in our analysis. The incidence of abnormal pregnancy outcomes in T. gondii infected pregnant women (infected group) was significantly higher than that in the uninfected pregnant women (control group) (OR = 5.10; 95% CI, 3.85-6.75). Toxoplasma gondii infection rate in the abnormal-pregnancy-outcome group was significantly higher than in the normal-pregnancy group (OR = 3.71; 95% CI, 3.31-4.15). The pooled rate of vertical transmission was 20% (95% CI, 15%-26%) in maternal infection of T. gondii. The incidences of vertical transmission in women who were infected in the first, second or third trimester of pregnancy were 5% (95% CI, 2%-16%), 13% (95% CI, 7%-23%), and 32% (95% CI, 24%-41%), respectively. The rates of vertical transmission in women who were treated with spiramycin-only, PSF (pyrimethamine + sulfadiazine + folinic acid) or PS (pyrimethamine + sulfadiazine) combined with spiramycin, or other untypical treatments were 13% (95% CI, 7%-22%), 13%(95% CI, 7%-25%), and 24%(95% CI, 18%-32%), respectively. Conclusions: Toxoplasma gondii infection can result in adverse pregnancy outcomes in pregnant women. The pooled rate of vertical transmission was 20% in maternal infection and the incidences of vertical transmission increased in the first, second or third trimester of pregnancy. The pooled rates of transmission in groups treated with spiramycin-only, PSF or PS combined with spiramycin, or other untypical treatments were not significantly different.