ABSTRACT
Background: Preterm delivery is the delivery between 20th - 37th weeks of gestation. The study aimed to study the maternal BMI, 25-Hydroxyvitamin D (25(OH)D) serum level, and uterine cervical length (CL) as predicting factors for PTD.
Methods: A prospective study included 188 pregnant women recruited during 20th - 24th weeks of gestation. The maternal BMI was calculated, the serum level of 25(OH)D was measured, and the uterine CL was measured via transabdominal and transvaginal ultrasound. All women followed until delivery time and then were divided into 2 groups; group1 (n=54) women who delivered preterm, and group2 (n=134) women who delivered at term.
Results: BMI results showed statistical significance between women who delivered preterm and those who delivered at term ‎(29.7±1.7 vs. 23.6±2.2 kg/m2, P<0.001). ‎Serum 25(OH)D showed no significant difference between the studied groups. CL was significantly shorter in women who delivered preterm than other group (32.39±5.93 vs. 44.42±4.17 mm, P<0.001). At 25 mm as a cut-off value for CL, the sensitivity, specificity, PPV, and NPV were 90.7%, 78.4%, 62.8%, and 95.5%, respectively. Women with BMI >25kg/m2 had significantly longer cervix than those who had BMI <25kg/m2. Regarding the effect of CL on the mode of delivery, 65.4% of women with CL Conclusions: Maternal BMI had a significant relation with PTD. Measuring the CL during 20th - 24th weeks helps predict preterm delivery and the mood of delivery. There is an association between BMI and cervical length.

Keywords: BMI; 25-Hydroxyvitamin D; Cervical Length; Preterm Delivery.