Objectives: Umbilical cord blood can be taken at birth and largely gives indication of fetal and maternal conditions. The aim of the study was to investigate the relation between sex hormones in cord blood and birth weight of newborns and pregnancy complications. Methods: Fifty cord blood samples were collected from newborns at labor room of Baghdad Teaching Hospital between May and October 2018. Blood was withdrawn from their mothers for lead analysis. Five milliliters (ml) of cord blood was taken, 3 ml was used for testosterone and estradiol analysis (using enzyme-linked immunosorbent assay) and 2 ml for lead measurement by lead care analyzer. Newborns weight and head circumference were measured. Delivered women were divided into four groups: Women with normal pregnancy, women with pre-eclampsia, diabetic women and polycystic ovary syndrome (PCOS) women. Results: There was no significant difference in age between women in all groups (P > 0.05). Birth weights, estradiol, and testosterone were significantly different between groups. Estradiol was higher in cord blood of newborns of PCOS women (P < 0.05) than others. Testosterone was higher in cord blood of babies of PCOS and pre-eclampsia women compared with those of diabetes (P < 0.05). There were no significant differences between male and female neonates regarding cord estradiol (3596.27 ± 1934.69, 3714.57 ± 1581.47 pg/ml respectively), and testosterone (393.18 ± 87.14, 361.43 ± 102.14 ng/ml respectively) (P > 0.05). Maternal lead levels correlated positively with cord lead (r = 0.905, P < 0.05), which correlated negatively with head circumference (r = −0.766, P < 0.05). Birth weight correlated negatively with estradiol (r = −0.295), but positively with testosterone (r = 0.006) (P > 0.05). Conclusion: Cord blood estradiol and testosterone levels do not differ between males and females. Estradiol was high in cord blood of PCOS mothers. Testosterone was high in cord blood of PCOS and pre-eclampsia mothers. The increase in cord lead causes decrease in babies head circumference.