ArticleAnnals of epidemiology2015
Clustering of retrospectively reported and prospectively observed time-to-pregnancy.
Article in Annals of epidemiology, 2015. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 4 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
4 citing papers in PubMed.
- Age among women and men, time to pregnancy and risk of miscarriage.BMC medicine · 2025Article
- Short- and long-term effect of contraceptive methods on fecundity.The European journal of contraception & reproductive health care : the official journal of the European Society of Contraception · 2019Observational
- Proximity to major roadways and prospectively-measured time-to-pregnancy and infertility.The Science of the total environment · 2017Article
- Women's Reproductive History Before the Diagnosis of Incident Endometriosis.Journal of women's health (2002) · 2016Article
Corrections and comments
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Authors and funding
5 authors.
Funding
Abstract
purposeGiven reportedly high clustering but limited validity of retrospectively reported time-to-pregnancy (TTP), we assessed within-woman clustering for retrospectively reported TTPs alone and including gold-standard prospectively observed TTPs among women with 2 or more retrospectively reported and 1 or more prospectively observed TTPs. We further investigated whether past trying times inform future trying time among women with 1 or more retrospectively reported and 1 or more prospectively observed TTPs.
methodsFive hundred one couples attempting pregnancy were prospectively observed until human chorionic gonadotropin pregnancy or 12 months of trying. Women reported TTP for past planned pregnancies. Clustering as measured by the frailty variance was estimated using discrete Cox frailty models, adjusted for age, body mass index, smoking at each attempt. Utility of past attempts to inform future attempts was assessed with discrete Cox models and relative risk regression, adjusted for enrollment age, body mass index, smoking.
resultsSeventy-five women with 2 or more prior pregnancies contributed 180 retrospective and 91 prospective TTPs for frailty modeling. Retrospectively reported TTP clustering was high (frailty variance = 0.89) but substantially lower when including prospectively observed TTPs (frailty variance = 0.42). Among 202 women with 1 or more prior pregnancies, past trying times did not inform future trying time.
conclusionsTTP recall rather than TTP may account for clustering. Past trying times may not inform future trying times.
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Registered trials
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