The health of the embryo is mainly depending upon the oxygen resource and nutrients from the mother. The present research aims to evaluate the effect of maternal B12 levels on the child weight. The pregnant women (n=20) were enrolled in the study at Kerbala maternity teaching hospital during October to March (23rd to 25th gestational week). The test was performed at Kerbala maternity teaching hospital. The blood was collected from the vitamin B12 group (B12 group) and healthy participants. Vitamin B12 deficient women showed significant (p=0.0317) decreased in the fetus weight. This decrease in the fetus birth weight and due to other complications, about 82.71% women underwent the caesarean section delivery. While, only 21.73% normal delivery occurs with vitamin B12 supplementation and healthy women, respectively. The presence of vitamin B12 deficiency leads to the premature delivery. The fetus birth weight was negatively associated with the presence of vitamin B12 scarcity. The vitamin B12 content was significantly lower (274.13±14.52 pg/ml) in the B12 deficient group as compared to healthy control (495.8±24.81 pg/ml). From the above study, we can conclude that vitamin B12 scarcity was associated with anemia in the mother, which in turn affected fetal weight. Vitamin B12 levels should be supervised before planning a pregnancy.