Toxoplasma Serology Status and Risk of Miscarriage, A Case-Control Study among Women with A History of Spontaneous Abortion

Toxoplasma gondii is one of the major causes of abortion in pregnant women. Most cases of abortion occur in the acute phase of infection and early pregnancy. In this study, the seroprevalence of anti-Toxoplasma gondii IgM and IgG antibodies was investigated in women with first spontaneous abortion. Also to determine the acute and chronic infections, all IgM and IgG positive serum samples were evaluated using IgG avidity assay. This research is a case-control study on 240 serum samples from women with first spontaneous abortion as the case group and 240 serum samples from women who had a normal delivery referred to hospital for a checkup and had no history of abortion as the control group. The level of IgM and IgG anti-Toxoplasma gondii antibodies were assessed in serum samples using Enzyme-linked immunosorbent assay (ELISA). To discriminate the acute and chronic infections, all IgM positive samples in both groups and IgG positive samples of case group were examined using IgG avidity. The Toxoplasma IgM antibody was detected in 3.3% (8/240) of case group and 0.4% (1/240) of the control group and there was a statistically significant difference between two groups (P=0.019, Odds Ratio=10.266). 47.5% and 46.3% of samples in the case and control groups were positive for Toxoplasma IgG antibody, respectively. Seven out of 8 (87.5%) IgM positive sera from the case group had low IgG avidity indicating the acute infection, whereas all positive IgG sera and 1 IgM positive sample which was related to control group showed a high IgG avidity indicating the chronic infection. Maternal acute toxoplasmosis during pregnancy is raised as one of the factors that increase the chance of spontaneous abortion. It is suggested to provide the necessary health training, especially on the parasite transmission ways to women before marriage, particularly the seronegative women, as well as the serological toxoplasmosis test in women before and during pregnancy is also recommended. PCR and IgG avidity assays should be performed in the medical diagnostic laboratories for accurate distinguishing of the initial infection of toxoplasmosis in the pregnant women.