The protective mechanism of vitamin D (VD) on the immune system played an important role behind many health problems including abortion. Our aim was to investigate the levels of VD and some immunomodulatory markers (IL-6, TNF-α and INF-γ) in pregnant women with threatened abortion (TA) and their effects on their obstetric health. This study including 132 pregnant participants with TA visiting maternity hospital in Babel province, Iraq. The demographic data including previous and current obstetrical history and body mass index were collected by well-trained researcher following structured questionnaire after obtaining their verbal consent. Laboratory Investigations were done with estimation of VD, IL-6, TNF-α and INF-γ. The mean level of VD was 19.83±43.59 ng/ml while the mean levels of IL-6: 389.45±70.88, TNF-α: 118.78±44.11 and INF-γ: 100.39±20.13 pg/ml with related percentage among participants for low VD was 84%, high IL-6 was 66%, high TNF-α was in 43% but only 23% had high INF-γ in relation with normal values. The frequency of abortion was significantly increased with low VD and high IL-6 (p<0.05) with high correlation between them (r2=0.89). High incidence of TA associated with low level of VD accompanied with high serum levels of IL-6. This adverse pregnancy outcome may be associated with some form of autoimmune diseases with evidence that hypovitaminosis D was correlated with high proinflammatory markers (IL-6, TNF- α and IFN- γ) and worse form of TA and the role of VD is to correct these pro-inflammatory markers.