The length of the fertile window is associated with the chance of spontaneously conceiving an ongoing pregnancy in subfertile couples
Abstract
BACKGROUND: The period in each menstrual cycle during which sexual intercourse can result in conception is called the "fertile window". Although the fertile window closes on the day of ovulation, little is known about the moment it opens. We defined the first day of normal sperm-mucus interaction as the opening of the fertile window. We hypothesized that length of the fertile window varies between couples and that the number of days the fertile window is "open" is related to the time to spontaneous conception. METHODS Serial post-coital tests and sperm-mucus penetration tests were performed to detect the first normal sperm-mucus interaction day. Ovulation was confirmed by serial ultrasound. Using Cox' regression analysis, we determined whether the fertile window length was associated with time to ongoing pregnancy. This association was expressed in fecundability ratios (FR). RESULTS The fertile window length was determined in 410 subfertile couples. The fertile window length varied among couples from <1 to >5 days. The FR increased with increasing fertile window length and varied between 0.11 (95% CI: 0.03-0.45) for a fertile window of 1 day, to 2.4 (95% CI: 1.1-5.2) for a fertile window of 5 days or more. CONCLUSIONS The longer the fertile window in subfertile couples, the higher is the probability of spontaneously conceiving an ongoing pregnancy.
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These apps assume each woman's fertile window is the same length, disregarding evidence that the length of the fertile window differs among women.
“These apps also assume each woman’s fertile window is the same length, disregarding evidence that the length of the fertile window differs among women (Keulers et al. 2007).”
From Real-life insights on menstrual cycles and ovulation using big data (2020) · cites this paper as Keulers et al. 2007
Cites
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Can apps and calendar methods predict ovulation with accuracy?
Johnson, S., Marriott, L., & Zinaman, M. (2018) · Current Medical Research and Opinion · doi:10.1080/03007995.2018.1475348 · Cited by 115 · see citing works
Real-life insights on menstrual cycles and ovulation using big data
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“the same length, disregarding evidence that the length of the fertile window differs among women (Keulers et al. 2007).”
Background
- Authors
- Keulers, M. J., Hamilton, C. J. C. M., Franx, A., Evers, J. L. H., & Bots, R. S. G. M.
- Affiliations
- Jeroen Bosch Ziekenhuis (NL)
- Elisabeth-TweeSteden Ziekenhuis (NL)
- Maastricht University Medical Centre (NL)
- Venue
- Human Reproduction
- Publisher
- Oxford University Press (OUP)
- Published
- 2007-04-20
- Volume
- 22
- Issue
- 6
- Pages
- 1652-1656
- ISSN
- 0268-1161 (ISSN-L)
- 1460-2350
- OpenAlex
- W2100091699
- Cited by
- 67
- References
- 13
- Citations by year
- 2026: 1 · 2025: 3 · 2024: 1 · 2022: 3 · 2021: 6 · 2020: 4 · 2019: 2 · 2018: 5 · 2017: 1 · 2016: 2 · 2015: 1 · 2014: 5 · 2013: 2 · 2012: 4
- FWCI
- 7.00
- Type
- journal article
- Language
- en
- Open access
- closed
- Locations
- Human Reproduction (publishedVersion)
- PubMed (publishedVersion)
- Topics
- Health Sciences › Medicine › Reproductive Medicine › Reproductive Health and Technologies
- Health Sciences › Medicine › Reproductive Medicine › Sperm and Testicular Function
- Health Sciences › Medicine › Public Health, Environmental and Occupational Health › Reproductive Biology and Fertility
- Keywords
- fertile window, subfertility, spontaneous conception, postcoital test, ovulation, time to pregnancy, couples
- MeSH terms
- Adult, Coitus, Family Characteristics, Female, Fertility, Fertilization, Humans, Male, Middle Aged, Ovulation, Ovulation Detection, Pregnancy, Sperm-Ovum Interactions
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