ArticleBMJ open2026
Impact of vitamin D supplementation on preterm births and premature rupture of membranes: a study protocol for a double-blind randomised controlled trial.
Article in BMJ open, 2026. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Not yet cited in PubMed.
What it found
Each row is one number read from the abstract, on the scale the paper reported it, with its interval. Left of the dashed line favours the treatment, right favours the comparator. Under each row is the sentence it came from. New to these charts? A ten-minute tutorial.
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
0 citing papers in PubMed.
No citing paper in PubMed yet.
Corrections and comments
PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.
Authors and funding
8 authors.
Funding
No grant is acknowledged in the PubMed record.
Abstract
introductionPreterm birth (PTB) is a major adverse outcome in developing countries, including India, with serious adverse consequences. Although the pathophysiology is not fully understood, maternal biomarkers influencing placental function may contribute to premature rupture of membranes and PTB. Vitamin D₃ supplementation during pregnancy may lower the risk of PTB, particularly in populations with a high prevalence of vitamin D deficiency (~90% in India). However, available biomarkers for PTB prediction are non-confirmatory, costly and not part of routine care. The aim of the study is to evaluate whether 2000 IU/day vitamin D₃ supplementation during pregnancy reduces PTB compared with 500 IU/day (standard care). METHODS AND ANALYSIS: Singleton pregnant women ≤18 weeks gestation with deficiency of 25-hydroxyvitamin D (<20 ng/mL) attending antenatal clinics will be randomised (n=902) in a double-blind trial to receive either 500 IU or 2000 IU/day of vitamin D₃ with 1000 mg elemental calcium until delivery. Women with chronic illness, infections (HIV, positive Venereal Disease Research Laboratory test and positive hepatitis B surface antigen test), assisted conception or planned relocation before study completion will be excluded. Baseline details such as socio-demographic data, diet, anthropometry, ultrasound findings and blood pressure will be collected. Monthly antenatal visits will include clinical monitoring, supplement distribution and compliance checks. Blood samples at baseline and second and third trimesters and cord blood will be collected to assess vitamin D-related markers, pregnancy-associated plasma protein A and haemoglobin. Urinary calcium-to-creatinine ratio will be measured mid-study. Birth outcomes and infant anthropometry will be recorded. Baseline and endline characteristics will be compared between study arms using the χ2 test or Fisher's exact test for categorical variables (depending on the expected frequencies) and the independent samples t-test or Mann-Whitney U test for continuous variables (following normality assessment). ETHICS AND DISSEMINATION: The study has been funded by the Department of Biotechnology, India (Grant Ref: BT/PR41941/MED/97/548/2021). Ethical clearance has been obtained from Institutional Ethics Committee (Ref No. IEC/344/2021), St. John's Medical College & Research Institute and Ethics Committee of Bangalore Medical College & Research Institute (BMCRI/EC/25/2024). Study data will be disseminated through peer-reviewed publications and conference presentations.
trial registrationTrial has been prospectively registered with Clinical Trials Registry - India (CTRI/2021/10/037658).
Indexed as
Identifiers
What OpenQuestion holds
Registered trials
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.