Pre-conception 25-hydroxyvitamin D (25(OH)D) and fecundability
Jukic AMZ, Baird DD, Weinberg CR, Wilcox AJ, McConnaughey DR, Steiner AZ
Human reproduction (Oxford, England) · 35 citations
How it was studied
- Design
- Cohort study (indexed by PubMed)
- Studied in
- People
- Main outcome
- Clinical events such as disease or death
Who paid for it
- Funding
- Independent funding
- Government
- National Institutes of Health
- Government
- National Institute of Environmental Health Sciences
- Government
- Eunice Kennedy Shriver National Institute of Child Health and Human Development
- Government
- Intramural NIH HHS
- Government
- NICHD NIH HHS
- Grants
- National Institute of Environmental Health Sciences (ES103086); Eunice Kennedy Shriver National Institute of Child Health and Human Development (R01-HD067683); Eunice Kennedy Shriver National Institute of Child Health and Human Development (R00HD079659); National Institute of Environmental Health Sciences (ES044003); National Institute of Environmental Health Sciences (ES049003); National Institutes of Health (Z01 ES049003); National Institutes of Health (R00HD079659); National Institutes of Health (R01 HD067683); National Institutes of Health (Z01 ES044003)
Based on 5 listed funder(s).
Publication
- Published
- 2019-07-30 · Hum Reprod · vol. 34 · issue 11 · pp. 2163–2172
- Publisher
- Oxford University Press
- Cited
- 39 citations · more than 87% of similar papers · 2.0× the field average
- References
- 53 works
- Access
- Open access (repository copy) · PUBLIC-DOMAIN
- Research areas
- Vitamin D Research Studies · Birth, Development, and Health · Reproductive Health and Contraception
- Keywords
- Fertility, Medicine, Prospective cohort study, Demography, Pregnancy, Gynecology, Infertility, Cohort, Cohort study, Obstetrics, Population, Internal medicine, Biology
- MeSH
- humans, vitamin d, pregnancy tests, preconception care, prospective studies, fertility, fertilization, ovulation, pregnancy, adult, female, time-to-pregnancy
6 authors
From US
- Anne Marie Z. Jukic · correspondingYale University; National Institute of Environmental Health Sciences
- Donna D. BairdNational Institute of Environmental Health Sciences
- Clarice Ring WeinbergNational Institute of Environmental Health Sciences
- Allen James WilcoxNational Institute of Environmental Health Sciences
- D. Robert McConnaugheyWestat (United States)
- Anne Z. SteinerDuke University Hospital
Abstract
Study question
Is pre-conception 25(OH)D associated with the per cycle probability of conception, i.e fecundability, in a prospective cohort study?
Summary answer
There are suggestive associations of high 25(OH)D (at least 50 ng/ml) with increased fecundability and low 25(OH)D (<20 ng/ml) with reduced fecundability, but the estimates were imprecise.
What is known already
Vitamin D has been associated with reproductive function and fertility in animal studies, but few human studies exist.
Study design, size, duration
This community-based prospective cohort study included 522 women attempting to become pregnant between 2010 and 2016. The women completed online daily and monthly diaries until a positive home pregnancy test was observed or 12 months had elapsed.
Participants/materials, setting, methods
The study included women from central North Carolina who were aged 30-44 with no history of infertility, with no more than 3 months of attempt time at recruitment. Women recorded vaginal bleeding so that the ongoing number of attempt cycles could be counted and used to quantify a woman's pregnancy attempt time. Blood collected at the study entry was analysed for 25(OH)D using liquid chromatography tandem mass spectrometry. Associations with fecundability were estimated with a log-binomial discrete time-to-event model.
Main results and the role of chance
Among 522 women, 257 conceived during the study. The mean age was 33 years and the mean 25(OH)D was 36 ng/ml. There was an estimated 10% higher fecundability with each 10 ng/ml increase in 25(OH)D (fecundability ratio (FR) 1.10, 95% CI: 0.96, 1.25). The suggestive dose-response association with the continuous measure of 25(OH)D was driven by women in the lowest and the highest categories of 25(OH)D. Compared to women with 25(OH)D of 30-40 ng/ml, women below 20 ng/ml had an estimated 45% reduction in fecundability (FR (CI): 0.55 (0.23, 1.32)), and women with at least 50 ng/ml had an estimated 35% increase in fecundability (FR (CI): 1.35 (0.95, 1.91)). Across these three categories (25(OH)D of 50 ng/ml), the probability of taking longer than 6 months to conceive was, respectively, 51% (17%, 74%), 28% (17%, 39%) and 15% (10%, 37%).
Limitations, reasons for caution
While the distribution of 25(OH)D was wide, the number of observed cycles with high 25(OH)D (N = 107) or low 25(OH)D (N = 56) was small.
Wider implications of the findings
Our findings are consistent with prior reports of reduced fertility in women with 25(OH)D concentrations below the clinically defined deficiency level (20 ng/ml). Further studies are needed to evaluate the possible reproductive benefits of considerably higher 25(OH)D concentration (>50 ng/ml).
Study funding/competing interest(s)
This research was supported by the Eunice Kennedy Shriver National Institute of Child Health and Human Development of the National Institutes of Health (NIH) under award numbers R00HD079659 and R01HD067683 and supported in part by the Intramural Research Program of the National Institute of Environmental Health Sciences, under projects ES103086, ES049003 and ES044003. ClearBlue ovulation predictor kits were generously donated to AMZJ and AJW by Swiss Precision Diagnostics. Drs Wilcox and Jukic report non-financial support from Swiss Precision Diagnostics during the conduct of the study; Dr Jukic reports non-financial support from Theralogix, LLC, outside the submitted work. Otherwise there are no competing interests.
Trial registration number
N/A.
Abstract via Europe PMC. Copyright remains with the authors or publisher.
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