Effects of Vaginal Progesterone on The Prevention of Preterm Delivery in Pregnant Women with Prior Spontaneous Preterm Birth

Abstract

BACKGROUND: The preterm birth rate in Thailand continues to rise. Moreover, perinatal morbidity and mortality are causing significant budget losses for treatment. Rayong Province had a preterm birth rate as high as 11% from 2017 to 2018, and progesterone was often used to prevent preterm birth.

OBJECTIVES: To study the rate of preterm birth after vaginal progesterone use among singleton pregnancies with prior spontaneous preterm birth.

METHODS: A retrospective cohort study was conducted with historical control from the medical records of 82 singleton pregnancies in women who had a history of preterm birth and used vaginal progesterone at Rayong Hospital from 2019 to 2021.

RESULTS: The preterm birth rate was 20.7% in pregnant women with previous preterm birth who used vaginal progesterone. Comparison of current gestational age and previous preterm gestational age showed the mean gestational age was 37.3±1.7 weeks and 32.1±3.2 weeks, respectively. The current gestational age was significantly higher than previous preterm gestational age by about 5.20 weeks of mean gestational age (95%CI:4.47,5.92) (p<0.001) and when clarified by previous preterm gestational age to intervals of less than 28 weeks, 28-32 weeks, and greater than 32 weeks. The study found that the current gestational age was significantly higher than the previous preterm gestational age (p<0.001) in all intervals.

CONCLUSION: The use of vaginal progesterone in a pregnancy with previous preterm delivery can reduce the preterm birth rate by 79.3% as well as increase the current gestational age.

Thaiclinicaltrials.org number, TCTR20220527007