ArticleBMJ (Clinical research ed.)2007
Sex ratio and time to pregnancy: analysis of four large European population surveys.
Article in BMJ (Clinical research ed.), 2007. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 8 papers.
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.
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Who cites it
8 citing papers in PubMed.
- Association of preconception maternal glucocorticoid concentrations with sex ratio at birth: Evidence from a prospective cohort study.Annals of epidemiology · 2025Article
- Factors influencing sex ratio at birth in Krosno, Poland.Scientific reports · 2024Article
- Agency in Fertility Decisions in Western Europe During the Demographic Transition: A Comparative Perspective.Demography · 2017Article
- Article
- Male Reproductive Disorders and Fertility Trends: Influences of Environment and Genetic Susceptibility.Physiological reviews · 2016Review
- Sperm counts and sperm sex ratio in male infertility patients.Asian journal of andrology · 2012Article
- Ratio of boys to girls at birth.BMJ (Clinical research ed.) · 2007Article
- Human semen quality and the secondary sex ratio.Asian journal of andrologyArticle
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Authors and funding
4 authors.
Funding
Abstract
objectiveTo test whether the secondary sex ratio (proportion of male births) is associated with time to pregnancy, a marker of fertility. Design Analysis of four large population surveys. Setting Denmark and the United Kingdom. Participants 49 506 pregnancies.
main outcome measureSecondary sex ratio.
resultsNo association was found between the sex ratio and time to pregnancy and no discernible trend was found for sex ratio with time to pregnancy, either within individual datasets or in the pooled analysis. The odds ratios were 0.97 (95% confidence interval 0.90 to 1.04) for contraceptive failures, 1.01 (0.96 to 1.05) for time to pregnancy of 2-4 months, 1.02 (0.97 to 1.08) for 5-10 months, 0.98 (0.93 to 1.03) for 11 months or more, and 0.88 (0.74 to 1.06) for fertility treatment, with 0-1 months as the reference category.
conclusionNo association was found between the secondary sex ratio and time to pregnancy.
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Registered trials
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