Objective: To investigate the effect of Toxoplasma (Tox) infection during pregnancy to the development of fetus and infant.
Methods: Enzyme linked immunoadsorbent assay (ELISA) was employed to detect Tox-IgM in peripheral blood of 3,908 pregnant women. To Tox-IgM positive cases, the umbilical blood of their neonates were sampled to detect Tox-IgM and abortion tissues were sampled to detect Tox-DNA with polymerase chain reaction. Infection group included 95 cases whose Tox-IgM or DNA were positive, and control group consisted of 119 cases without infection. Different supervision methods were used to periodically observe the intelligence development of infants 3 and 12 months after birth in these two groups. After initial intervention, verbal intelligence quotients (VIQs), performance intelligence quotients (PIQs) and full scale intelligence quotients (FSIQs) were assessed when the infants were 1 and 4 years old of these two groups.
Results: The incidences of abortion, stillbirth, pre-term delivery, FGR and malformation in infection group were 12 cases (12.6%), 5 cases (5.3%), 4 cases (4.2%), 4 cases (4.2%) and 3 cases (3.2%), while the incidences of these abnormalities in control group were 3 cases (2.7%), 1 cases (0.9%), 2 cases (1.8%), 2 cases (1.8%) and 1 cases (0.9%). Comparing with these two groups, there was significant difference (P < 0.01). Relative risk (RR) of these 5 abnormalities was 4.7, 5.9, 2.3, 2.3 and 3.6 respectively. Mental development index (MDI) and psychomotor development index (PDI) of infants in infection group were 93 +/- 13 and 101 +/- 16. They were significantly lower than that of control group, which were 107 +/- 17 and 111 +/- 13. There was significant difference between these two groups (P < 0.05). After intervention in 1 and 4 years, their VIQs, PIQs and FSIQs were apparently improved (P < 0.05).
Conclusion: Congenital Tox infection is closely correlated with abnormal pregnancy outcomes and infantile mental retardation. Early intervention can improve intelligence development.