© 2020 Informa UK Limited, trading as Taylor & Francis Group.Aims: The aim of the present study was to evaluate umbilical cord N-terminal procollagen of type l collagen (P1NP) and beta C-terminal telopeptide (βCTX) levels in term pregnancies with vitamin D deficiency. Materials and methods: Ninety-two pregnant women between 19 and 35-years-old who delivered at term gestational age were included in the study and divided into deficient (n = 32), insufficient (n = 30), and normal (control) vitamin D levels (n = 30). Results: Maternal demographic characteristics and biochemical parameters were similar among groups. The mean umbilical cord P1NP level was 221.4 (211.7–231.0, 95%CI) pg/mL in the vitamin D deficiency group, 282.5 (271.2–293.8, 95%CI) pg/mL in the vitamin D insufficiency group, and 280.9 (270.9–290.8, 95%CI) pg/mL in the control group and significantly lower in vitamin D deficiency group than others (p <.001). Umbilical cord P1NP level was similar in the vitamin D insufficiency group and control group (p =.971). The mean umbilical cord βCTX level was 5530, 9 (5511.5–5550.3, 95%CI) pg/mL in the vitamin D deficiency group, 5516.3 (5498.4–5534.2, 95%CI) pg/mL in the vitamin D insufficiency group, and 5510 (5491.4–5528.5, 95%CI) pg/mL in the control group, which was statistically similar among the groups (p =.251). Conclusion: Our results indicated that vitamin D deficiency during pregnancy affects fetal bone osteoblast activity.