Background: Viral invading of host cell may lead to immunosuppression and subsequently enhance secondary infection by other Infectious pathogens.Aim: To determine whether co-infection of TORCH complex agents increase the development of bad obstetric outcome (BOH).Patients and methods: The total number of women included in the study was 838; of them 547 had BOH, and 291 had normal pregnancy history. In the BOH group, 292 (53.4%) women were pregnant, while in the normal pregnancy group, 140 (48.1%) were pregnant. Parvovirus IgM and IgG were determined in 88 women (28 controls, 20 inevitable abortion, and 40 BOH). IgG and IgM antibodies were detected in sera of all groups using ELISA method.Results: Co-infection had a high rate (77.8%) in our studied population. Ten patterns of co-infections were recognized, but the predominant one was rubella and CMV (42.5%). There was a significant frequency difference in seroprevalence of (T.gondii plus CMV, p=0.038), (T. gondi + rubella + CMV, p=0.001) and (Toxoplasma + HSV-2 + CMV, p=0.015)between women with BOH and control group. Parvovirus co-infections were significantly (p=0.000) different between BOH, inevitable abortion and control groups. In addition, there was a significant difference in mixed parvovirus infection between BOH versus control; non-pregnant BOH versus non-pregnant control; and abortion versus normal pregnancy. Furthermore, the frequency of parvovirus mixed infections were significantly more frequent (p=0.000) in women with BOH (88.3%) compared to control (25%). CMV with other agents was the predominant (77%) mixed infection, followed by parvovirus with others (68.2%) and rubella with others (66.7%). Rubella with others and parvovirus with others were with significant differences between women with BOH and control.Conclusion: CMV, Parvovirus, Rubella, HV-2 and Toxoplasma coinfections was a risk factor that increased development of BOH. CMV may play an important role as primary infection that leads to immunosuppression and enhancement of secondary pathogen infection.