The objectives of the study were to determine placental weight as well as factors associated with low placental weight and to determine its impact on some anthropometrical parameters in the newborn. A total of 300 freshly delivered placentas were examined in this longitudinal-prospective study. Sobi Specialist Hospital, Alagbado, Ilorin, and Surulere Medical Centre, Eruda, Ilorin, were used for sample collections. Informed consent was obtained from patients and institutional ethical clearance was obtained from Kwara State Ministry of Health (MOH/KS/ECI/777/82). Semistructured questionnaire was used to gather data on the patients and newborns demographic indices. Analysis of variance, Student’st-test, regression analysis, and Pearson moment correlation statistical analysis were employed to analyze the data. The mean wet placental weight for normal pregnancies was 529 g (SD = 84.01). Placental weight to birth weight ratio of 1 : 5.83 was generated, 529 g impact on newborn head circumference (mean: male = 35.30 cm, female = 34.90 cm) having a linear correlation. Regression analysis showed negative association between female babies (2.99 kg) placental weight (r=0.369;P≤0.05), birth weight, and cord length (mean = 58.4 cm). Placental weight correlation with male newborn weight (3.14 kg) had placental birth weight ratio of 0.679 between 90th and 10th percentileP<0.05with head circumference (r=0.473,P<0.05), lower limit placental diameter 22.80 ± 1.76 cm (SD = 4.8), BMI ≤ 19.50, and Apgar score of 7/10. It is concluded that blood holding capacity of the placenta (relative to weight) and the maternal-dietary have influence on placental weight. Differences in hormonal environment in utero and pathologic adaptation of placenta, due to racial factors, significantly contributed to the size of newborn baby.