Alcohol consumption and fecundability: prospective Danish cohort studyBMJ 2016; 354 doi: https://doi.org/10.1136/bmj.i4262 (Published 31 August 2016) Cite this as: BMJ 2016;354:i4262
- Ellen M Mikkelsen, senior researcher1,
- Anders H Riis, biostatistician1,
- Lauren A Wise, professor2,
- Elizabeth E Hatch, professor2,
- Kenneth J Rothman, professor2 3,
- Heidi T Cueto, post doc1,
- Henrik Toft Sørensen, professor1 2
- 1Department of Clinical Epidemiology, Aarhus University Hospital, 8200 Aarhus N, Denmark
- 2Department of Epidemiology, Boston University School of Public Health, Boston, MA, 617857, USA
- 3RTI Health Solutions, Research Triangle Park, NC, 27709 USA
- Correspondence to: E M Mikkelsen
- Accepted 28 July 2016
Objective To investigate to what extent alcohol consumption affects female fecundability.
Design Prospective cohort study.
Setting Denmark, 1 June 2007 to 5 January 2016.
Participants 6120 female Danish residents, aged 21-45 years, in a stable relationship with a male partner, who were trying to conceive and not receiving fertility treatment.
Main outcome measures Alcohol consumption was self reported as beer (330 mL bottles), red or white wine (120 mL glasses), dessert wine (50 mL glasses), and spirits (20 mL) and categorized in standard servings per week (none, 1-3, 4-7, 8-13, and ≥14). Participants contributed menstrual cycles at risk until the report of pregnancy, start of fertility treatment, loss to follow-up, or end of observation (maximum 12 menstrual cycles). A proportional probability regression model was used to estimate fecundability ratios (cycle specific probability of conception among exposed women divided by that among unexposed women).
Results 4210 (69%) participants achieved a pregnancy during follow-up. Median alcohol intake was 2.0 (interquartile range 0-3.5) servings per week. Compared with no alcohol consumption, the adjusted fecundability ratios for alcohol consumption of 1-3, 4-7, 8-13, and 14 or more servings per week were 0.97 (95% confidence interval 0.91 to 1.03), 1.01 (0.93 to 1.10), 1.01 (0.87 to 1.16) and 0.82 (0.60 to 1.12), respectively. Compared with no alcohol intake, the adjusted fecundability ratios for women who consumed only wine (≥3 servings), beer (≥3 servings), or spirits (≥2 servings) were 1.05 (0.91 to1.21), 0.92 (0.65 to 1.29), and 0.85 (0.61 to 1.17), respectively. The data did not distinguish between regular and binge drinking, which may be important if large amounts of alcohol are consumed during the fertile window.
Conclusion Consumption of less than 14 servings of alcohol per week seemed to have no discernible effect on fertility. No appreciable difference in fecundability was observed by level of consumption of beer and wine.
We are grateful to Tina Christensen for her support in data collection and media contacts. We thank all the women who participated.
Contributors: EMM wrote the first and successive drafts of the paper. AHR did the statistical analyses. All authors contributed to the design of the study and the interpretation of the results, and all reviewed and approved the final manuscript. EMM is the guarantor.
Funding: The study was supported by the National Institute of Child Health and Human Development (R21-HD050264 and R01-HD060690) and the Danish Medical Research Council (271-07-0338). The researchers are all independent of the funders.
Competing interests: All authors have completed the ICMJE uniform disclosure form at www.icmje.org/coi_disclosure.pdf (available on request from the corresponding author) and declare: support from the National Institute of Child Health and Human Development and Danish Medical Research Council for the submitted work; no financial relationships with any organizations that might have an interest in the submitted work in the previous three years; no other relationships or activities that could appear to have influenced the submitted work.
Ethical approval: The study was approved by the Danish Data Protection Agency (J.nr. 2013-41-1922) and the Institutional Review Board at Boston University. Ethical approval was not needed according to the Danish Ethical Review System.
Data sharing: No additional data available.
Transparency: The lead author affirms that the manuscript is an honest, accurate, and transparent account of the study being reported; that no important aspects of the study have been omitted; and that any discrepancies from the study as planned (and, if relevant, registered) have been explained.
This is an Open Access article distributed in accordance with the terms of the Creative Commons Attribution (CC BY 3.0) license, which permits others to distribute, remix, adapt and build upon this work, for commercial use, provided the original work is properly cited. See: http://creativecommons.org/licenses/by/3.0/.