Hormonal biomarkers and preterm birth: insights from a study of pregnant women in Lahore, Pakistan.

Objective. Reduced calciferol (vitamin D) levels in pregnant women have been associated with an increased risk to infant health. Progesterone sustains pregnancy and reduces the risk of premature birth through its metabolites affecting myometrial contractility. Sex hormone-binding globulin protein (SHBG) is a biomarker of premature birth. The present study aimed to find out if early pregnancy levels of vitamin D, SHBG, and progesterone metabolites may predict preterm birth risk. Methods. Five hundred pregnant women aged 18-43 years during their 2nd and 3rd trimesters from multiple civilian regional medical centers in Lahore participated in the study. Blood samples taken from participants were used to determine vitamin D, SHBG, 11-deoxycorticosterone (DOC), and 16α-hydroxyprogesterone (16α-OHP) levels using specific ELISA kits. Statistical analysis was performed by one-way ANOVA using the latest GraphPad Prism software. Results. A significant decrease in vitamin D, DOC, and SHBG levels (p<0.001, p<0.001, and p<0.05, respectively) in the preterm birth cohorts in the 2nd and 3rd trimester was found compared to the corresponding control groups. Furthermore, 16α-OHP levels in the preterm birth cohorts in the 2nd and 3rd trimesters were significantly increased (p<0.001 and p=0.0062, respectively) compared to their control cohorts. Conclusion. The results of our study confirm that calciferol deficiency in pregnant women is associated with an increased risk of premature birth and indicate that SHBG and progesterone metabolites may be useful biomarkers for the early identification and prediction of preterm birth.