Trial reportBJOG : an international journal of obstetrics and gynaecology2025
Progesterone Luteal Support in Natural Cycles for Unexplained Infertility: A Randomised Controlled Trial (The PiNC Trial).
Trial report in BJOG : an international journal of obstetrics and gynaecology, 2025. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 1 paper.
What it found
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The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.
The trial behind it
Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.
Neither the registry nor the abstract names a trial number. If this is a trial report, that itself is worth knowing.
Who cites it
1 citing paper in PubMed.
- Targeting the PRMT5/Nur77 methylation axis enhances endometrial decidualization capacity and female fertility in preclinical models.The Journal of clinical investigation · 2026Article
Corrections and comments
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Authors and funding
8 authors.
Funding
Abstract
objectiveTo compare the effect of luteal-phase progesterone supplementation in natural cycles to expectant management on live birth rates in women with unexplained infertility (UI).
designAn open-label, parallel-arm, single-centre randomised controlled trial.
settingOne tertiary NHS-funded fertility unit. POPULATION: Couples with UI for at least 1 year.
methodA comparison of luteal phase micronised vaginal progesterone treatment (400 mg bd) with timed intercourse and timed intercourse alone for 3 cycles.
main outcome measuresPrimary outcome: Livebirth rate. SECONDARY OUTCOMES: Biochemical pregnancy, clinical pregnancy, mid-luteal serum progesterone and pregnancy loss.
resultsOne hundred and forty-three couples were randomised. Livebirth rates were 11/72 (15.3%) in the treatment group versus 5/71 (7.0%) in the control group (RR 2.17, 95% CI 0.79-5.93). Biochemical pregnancy rates were 15/72 (20.8%) versus 10/71 (14.1%), (RR 1.48, 95% CI 0.72-3.07) and clinical pregnancy rates were 14/72 (19.4%) versus 9/71 (12.7%), (RR 1.53, 95% CI 0.71-3.31) in the treatment and control groups respectively. Pregnancy losses: 4/15 treatment group versus 5/10 control group (RR 0.53, 95% CI 0.19-1.51). One biochemical pregnancy loss in each group and 2/15 miscarriages in the treatment group versus 3/10 in the control group. Total miscarriage rates including biochemical losses were 3/15 (20%) versus 4/10 (40%) (RR 0.5, 95% CI 0.14-1.77).
conclusionsThe results did not reach statistical significance. However, the difference in livebirth rates warrants further investigation as this simple, noninvasive, inexpensive treatment would be a very attractive option for affected couples. A larger trial using the effect size from this study to guide sample size is planned.
trial registrationThe PiNC trial was registered with the EU Clinical Trials Register on 29/11/2019 www.clinicaltrialsregister.eu/ctr-search/search?query=homerton. The first participant was recruited on 25/2/2020.
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Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.