ToRCH Pathogens-Induced Histopathological Changes in Placental Tissues and Associated Post Obstetric Complications

Background: Maternal infections caused by the ToRCH complex, comprising Toxoplasma gondii (T.gondii), Rubella Virus (RV), Cytomegalovirus (CMV), and Herpes Simplex Virus (HSV), are significant contributors to Bad Obstetric History (BOH). These infections can vertically transmit through the placental barrier, leading to complications in fetal development. This study investigates the histopathological changes induced by ToRCH pathogens in placental tissues and their association with post-obstetric complications in Pakistani women.

Methodology: A total of 83 women were enrolled in the study and divided into two groups: the Experimental group and the Control group. The Experimental group consisted of women with BOH and was further subdivided into two categories: Group A and Group B. Group A comprised women who experienced a recent miscarriage at the time of sample collection, while Group B consisted of women who gave birth normally at the time of sample collection. In contrast, the Control group included women with normal delivery and a normal obstetric history. To investigate ToRCH infections, venous blood samples were analyzed for ToRCH antibodies using enzyme-linked immunosorbent assay (ELISA). Additionally, small pieces of placental tissue collected after miscarriage or delivery were subjected to nucleic acid (NA) detection by conventional polymerase chain reaction (PCR) using ToRCH pathogen-specific primers. Histopathological examination of placental tissue was also performed to identify microscopic changes. The data obtained were analyzed using descriptive statistics (percentages) and chi-square tests to determine significant associations.

Results: The study revealed an overall seroprevalence of ToRCH pathogens of 57.83% in the study population, with 53.01% detected in the Experimental group and 4.81% in the Control group. In the Experimental group, IgM and IgG antibodies were detected in 14.45% and 37.34% of participants, respectively, with 1.20% testing positive for both. Notably, the Control group showed no IgM positivity, while IgG was detected in 4.81%. Nucleic acid (NA) detection revealed ToRCH pathogens in 54.21% of placental tissues from the Experimental group only. Specifically, antibodies for T.gondii and RV were most prevalent (19.27% each), while NA detection was highest for RV, CMV, and HSV (14.45% each). In contrast, the Control group showed minimal antibody detection, with only 2.40% positivity for T.gondii and CMV each. Statistical analysis revealed significant differences in ToRCH infection (antibodies and NA) between study groups for CMV only (p > 0.05). Discrepancies between ToRCH antibodies and NA positivity were observed in 75.90% of cases, with 71.08% occurring in the Experimental group and 4.81% in the Control group. Histopathological examination revealed chorionic villitis (CV) in 16.86% of the Experimental group; specifically 10.84% in Group A and 6.02% in Group B. CV was detected in women infected with T.gondii (in 4 cases), RV (in 6 cases), CMV, and HSV (both in 2 cases, each). The most common previous BOH complications were recurrent spontaneous abortions (RSAs) (47.05%), with 21.87% of these cases showing CV positivity.

Conclusion: The study's key conclusion is that ToRCH pathogens are prevalent in the study population, and CV was identified as the primary histopathological change associated with BOH complications (majorly RSAs). These results underscore the importance of investigating ToRCH infections in women experiencing BOH complications.