Oral Concurrent Session 1 - Prematurity
Oral Concurrent Sessions
Multicenter randomized controlled trial was conducted during 2018-2022 at three university affiliated medical centers. Women with a history of preterm delivery or cervical shortening in the current pregnancy were excluded. Patients with arrested pre-term labor following tocolytics at 24-34 gestational weeks were randomly allocated to receive vaginal micronized progesterone 200 mg twice daily or no treatment until 36.6 weeks. The primary outcomes were the number of days from enrollment to delivery and the rate of spontaneous preterm delivery prior to 37 weeks of gestation. A sample size of 128 women was required to detect a difference of 7 ± 14 days in pregnancy prolongation and a reduction from 50% to 25% in the rate of spontaneous preterm delivery (5% two-sided alpha, 80% and 84% power, respectively).
Results:
Sixty four and 65 women were allocated to the no treatment and treatment groups, respectively. Demographic characteristics were similar. Study outcomes are presented in the table. Comparing no treatment with treatment, there was no difference in the number of days from enrolment to delivery (37.4±20.3 versus 40.0±17.8, respectively; P=0.44), the overall rate of preterm delivery (28 (44%) versus 19 (30%), respectively; P=0.09), and the rate of spontaneous preterm delivery (19 (30%) versus 16 (25%), respectively; P=0.52). In twins (table), compared with no treatment, micronized progesterone was associated with increased number of days from enrolment to delivery (26.1±15.2 versus 43.7±18.1, respectively; P=0.02), later delivery week (34.7±2.2 versus 36.5±1.4, respectively; P=0.01) and increased birth weight (2018±430 versus 2444±528 gr, respectively; P=0.01).
Conclusion: Vaginal micronized progesterone following arrested preterm labor was not an effective treatment to prolong pregnancy or prevent spontaneous preterm delivery. Further research should be conducted regarding possible favorable effect in twins.