Does vaginal progesterone prevent miscarriages after early pregnancy bleeding? The research world has yet to agree, but a recently published Australian study (aka "the STOP trial") attempted to tackle this question.

After seven years of recruiting ~300 women, the STOP trial was stopped prematurely based on early results.

Hurdles with study execution plus thinly-disguised jabs at other research made for an interesting paper.

Bordewijk EM, Li W, Gurrin LC, Thornton JG, van Wely M, Mol BW. An investigation of seven other publications by the first author of a retracted paper due to doubts about data integrity. Eur J Obstet Gynecol Reprod Biol. 2021;261:236-241. doi:10.1016/j.ejogrb.2021.04.018

Carmichael SL, Shaw GM, Laurent C, Croughan MS, Olney RS, Lammer EJ. Maternal progestin intake and risk of hypospadias. Arch Pediatr Adolesc Med. 2005 Oct;159(10):957-62. doi: 10.1001/archpedi.159.10.957. PMID: 16203941.

Casarramona G, Lalmahomed T, Lemmen C, et al. The efficacy and safety of luteal phase support with progesterone following ovarian stimulation and intrauterine insemination: A systematic review and meta-analysis. Front Endocrinol (Lausanne). 2022;13:960393. Published 2022 Sep 2. doi:10.3389/fendo.2022.960393

Coomarasamy A, Devall AJ, Cheed V, et al. A Randomized Trial of Progesterone in Women with Bleeding in Early Pregnancy. N Engl J Med. 2019;380(19):1815-1824. doi:10.1056/NEJMoa1813730.

Devall AJ, Papadopoulou A, Podesek M, et al. Progestogens for preventing miscarriage: a network meta-analysis. Cochrane Database Syst Rev. 2021;4(4):CD013792. Published 2021 Apr 19. doi:10.1002/14651858.CD013792.pub2

McLindon LA, James G, Beckmann MM, et al. Progesterone for women with threatened miscarriage (STOP trial): a placebo-controlled randomized clinical trial [published online ahead of print, 2023 Feb 20]. Hum Reprod. 2023;dead029. doi:10.1093/humrep/dead029

Meurer WJ, Tolles J. Interim Analyses During Group Sequential Clinical Trials. JAMA. 2021;326(15):1524-1525. doi:10.1001/jama.2021.10174

Oripro (progesterone pessary used in clinical trial) accessible at https://www.healthdirect.gov.au/medicines/brand/amt,124041000036109/oripro

Şükür YE, Göç G, Köse O, et al. The effects of subchorionic hematoma on pregnancy outcome in patients with threatened abortion. J Turk Ger Gynecol Assoc. 2014;15(4):239-242. Published 2014 Dec 1. doi:10.5152/jtgga.2014.14170

Yan X, Xu H, Li J, Xu Z, Niu Y, Wang Y. Subchorionic hematoma and risk of preterm delivery: a systematic review and meta-analysis. Am J Obstet Gynecol MFM. 2023;5(1):100791. doi:10.1016/j.ajogmf.2022.100791