Maren Beatrice Smith

University of California, Irvine School of Medicine
United States

Abstract Title: Investigating the Relationship between Salivary Estriol to Progesterone Ratio and Onset of Labor: A Feasibility Study

Biography:

Maren Smith is a current third year medical student at the University of California, Irvine School of Medicine. She is interested in general surgery and specifically trauma surgery. Her previous research publications have been on emergency room and pre-hospital informatics, the timing of surgical intervention for morel-lavallee injuries, and the use of salivary hormones to predict preterm and term labor. Maren will be applying into the 2025-2026 ERAS cycle and is excited to start her intern year.

Research Interest:

Serum hormone levels have been extensively studied as potential biomarkers for preterm, term, and late-term labor. In a pilot study by Darne et al., researchers found that the median salivary estriol (E3) to progesterone (P) ratios in pregnant females (PF) rose acutely to >1.65 (pg/ml) 24 hours before the onset of labor. Our study aimed to examine daily salivary estriol (E3) to progesterone (P) ratios to determine the relationship between salivary hormone levels and labor onset. This was a single-center prospective pilot study. Eight PF were recruited to collect passive drool saliva samples daily from 38 weeks gestation until labor onset. PF with a history of preterm labor, age < 18, multi-fetal gestation, tobacco or substance use disorder, use of corticosteroids, or a planned induction were excluded. Saliva was tested in duplicate using a commercially available enzyme-linked immunosorbent assay kit (ELISA). Estriol values between PF varied widely with a range of 671-5438 (pg/ml), a median value of 2496 pg/mL, and a standard deviation (SD) of 1145.17. Conversely, E3:P ratios between PF varied less with a range of 0.32-2.51 (pg/ml), a median value of 0.99, and a SD of 0.50. Higher peak E3:P values (1.22-2.51 (pg/ml)) were noted in five of the eight (62%) PF who went into spontaneous labor. Three of the eight PF (37.5%) were induced with lower peak E3:P values in comparison (0.69- 1.2 (pg/ml)). Our study observed wide variations in salivary estriol levels between PF while E3:P ratios were more consistent and deserve further investigation. While this study had limited power, a relationship may exist between lower E3:P ratios and the need for induction of labor, suggesting the need for further investigation with a larger study.