Background: We measure the umbilical cord thickness of newborn just after delivery with digital Vernier caliper and correlate the association with antenatal maternal risk factors. This helps the pediatricians to predict which newborn need close monitoring. Objectives: The aim of indexed study to evaluate the umbilical cord thickness, maternal antenatal risk factors and determines the association between umbilical cord thickness and antenatal maternal risk factors. Methods: This is a cross sectional prospective study conducted between 2020 and 2021 at Rajkiya Mahila Chikitsalaya, J L N Medical College, Ajmer, India. Total 303 newborn subjected for this study. Out of these 189 newborn enrolled as control group for this study. Enrolment of sample was simple as our convenience during the study period. Results: Mean umbilical cord diameter was found smaller in newborns which associated with antenatal risk factors as compared to controls without antenatal risk factors (cases: 9.89 ± 2.53 mm; controls: 10.56 ± 2.26 mm) and the difference was statistically significant (P = 0.03). Oligohydramnios and meconium-stained liquor were found to be associated with the smaller umbilical cord diameter (P < 0.01). Conclusions: Oligohydramnios and meconium-stained liquor were found to be significantly associated with the thin umbilical cord.