Effect of third trimester maternal vitamin D levels on placental weight to birth weight ratio in uncomplicated pregnancies

Objectives: Vitamin D has critical role for the fetal and placental development. Today, placental weight (PW), fetal birth weight (BW), and the PW/BW ratio are used as markers of fetal development. The aim of this study is to evaluate the relationship between vitamin D levels and these markers in uncomplicated pregnancies. Methods: This study included 108 women with uncomplicated pregnancies, defined as full-term and healthy pregnancies without perinatal complications. Vitamin D levels < 12 ng/mL were classified as deficient, 12-20 ng/mL as insufficient, and > 20 ng/mL as normal. Postnatal BW and PW were compared according to maternal serum vitamin D levels. Results: Maternal age, maternal height, maternal weight, body mass index, nulliparity, gestational age at delivery, mode of delivery, and fetal gender were similar between groups. Postnatal BW, PW, fetal height at birth, and fetal head circumference parameters were similar between the groups. The PW/BW ratio was 21.77 +/- 2.20 in the vitamin D deficient group, 21.20 +/- 2.40 in the insufficient group, and 19.98 +/- 2.37 in the normal group (p=0.012). In addition, there was a significant negative correlation between vitamin D level and the PW/BW ratio (p=0.012, r=0.031). Conclusions: Our results indicated that PW/BW ratio which is the marker for prediction adverse perinatal outcomes were significantly increased in the presence of vitamin D deficiency and insufficiency.