The DOI matches its Crossref record; 46 of the 46 references it cites were found in a registry or an index.
Time to pregnancy and semen parameters: a cross-sectional study among fertile couples from four European cities
Abstract
Background In fertile populations, little is known about the association between semen parameters and time to pregnancy (TTP). Methods Pregnant women from Copenhagen, Edinburgh, Paris and Turku who conceived without medical intervention were asked for their TTP (942 couples), and their partners provided a semen sample. The proportion of morphologically normal sperm and the multiple anomalies index (MAI, ratio of the total number of anomalies to the number of abnormal sperm) were centrally estimated. We estimated rate ratios for the occurrence of a pregnancy by a discrete survival model, adjusted for sexual activity and female factors affecting fecundity. Results Increasing sperm concentration influenced TTP up to 55 x 10(6)/ml. The proportion of morphologically normal sperm influenced TTP up to 39% according to David's criteria, and this association held among the subjects with a sperm concentration >55 x 10(6)/ml. For strict criteria, the threshold value was 19% normal sperm. An increase of 0.5 in MAI was associated with an adjusted rate ratio for the occurrence of a pregnancy of 0.68 (95% confidence interval: 0.54-0.85). Conclusions These results highlight the importance of sperm morphology parameters and indicate that the effect of proportion of normal sperm on TTP may be independent of sperm concentration.
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“Epidemiological studies comparing fertile men whose partners achieved natural pregnancy and infertile men have demonstrated that sperm morphology was correlated with the chances of natural pregnancy [1, 2, 3].”
From Recommendations for Human Sperm Morphology Assessment in 2025: An Expert Review From the French BLEFCO Group (2026) · cites this paper as [3]
In the citing paper
“In these studies, although correlations were observed between morphology and natural fertility, the predictive value of sperm parameters for detecting infertility was low.”
From Recommendations for Human Sperm Morphology Assessment in 2025: An Expert Review From the French BLEFCO Group (2026) · cites this paper as [3]
In the citing paper
“The MAI [3, 70] and the TZI were correlated with fertility in vivo, but their sensitivity and specificity were mediocre (< 75%).”
From Recommendations for Human Sperm Morphology Assessment in 2025: An Expert Review From the French BLEFCO Group (2026) · cites this paper as [3]
In the citing paper
“Despite efforts to standardize methodology for grading sperm morphology, publications examining the impact morphology on spontaneous pregnancy, intrauterine insemination, and in vitro fertilization reach varying conclusions (2, 3, 4, 5, 6, 7, 8, 9, 10).”
From Poor reproducibility of percentage of normally shaped sperm using the World Health Organization Fifth Edition strict grading criteria (2022) · cites this paper as [3]
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Metadata
- Authors
- Slama, R.
- Affiliations
- Inserm (FR)
- Corresponding author
- Slama, R.
- ORCID
- Slama, R.
- Venue
- Human Reproduction
- Publisher
- Oxford University Press (OUP)
- Published
- 2002-02-01
- Volume
- 17
- Issue
- 2
- Pages
- 503-515
- ISSN
- 0268-1161 (ISSN-L)
- 1460-2350
- OpenAlex
- W2135968453
- Cited by
- 308
- References
- 46
- Citations by year
- 2026: 4 · 2025: 11 · 2024: 14 · 2023: 12 · 2022: 11 · 2021: 13 · 2020: 17 · 2019: 16 · 2018: 12 · 2017: 16 · 2016: 18 · 2015: 14 · 2014: 16 · 2013: 22 · 2012: 13
- FWCI
- 8.74
- Type
- journal article
- Language
- en
- Open access
- closed
- Locations
- Human Reproduction (publishedVersion)
- PubMed (publishedVersion)
- Research at the University of Copenhagen (University of Copenhagen) (submittedVersion)
- University of Southern Denmark Research Portal (University of Southern Denmark) (submittedVersion)
- Funders
- European Commission
- Topics
- Health Sciences › Medicine › Reproductive Medicine › Sperm and Testicular Function
- Health Sciences › Medicine › Reproductive Medicine › Reproductive Health and Technologies
- Health Sciences › Medicine › Urology › Male Reproductive Health Studies
- Keywords
- time to pregnancy, semen parameters, sperm concentration, sperm morphology, spontaneous conception, fertility, fecundability
- MeSH terms
- Cross-Sectional Studies, Europe, Female, Fertility, Fertilization, Humans, Male, Pregnancy, Probability, Semen, Sperm Count, Spermatozoa, Time Factors
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