Post‐partum interval and time to pregnancy in a prospective preconception cohort
Bibliographic record
Abstract
BACKGROUND: Little is known about the influence of the post-partum interval-defined as the time between giving birth and attempting to conceive again-on subsequent fecundability. OBJECTIVES: We evaluated the association between the post-partum interval and fecundability in Pregnancy Study Online (PRESTO), a web-based prospective preconception cohort of pregnancy planners from the United States and Canada. METHODS: Eligible women were aged 21-45 years, attempting pregnancy, and not using fertility treatment. Women completed a baseline questionnaire to ascertain information on demographics, life style factors, and reproductive history, including detailed information on all previous pregnancies. They completed bi-monthly follow-up questionnaires for up to 12 months to update pregnancy status over time. We used proportional probabilities regression models to estimate fecundability ratios (FRs) and 95% confidence intervals (CIs) adjusted for sociodemographic and reproductive history covariates. Analyses were restricted to multiparous women who had been attempting pregnancy with the same male partner for ≤6 menstrual cycles at enrolment. RESULTS: During 2013-2019, 1489 female participants contributed 959 pregnancies and 5003 cycles. The median post-partum interval was 18 months. Compared with a 12- to 23-month post-partum interval, FRs for post-partum intervals of <12, 24-47, and ≥48 months were 0.89 (95% CI 0.77, 1.04), 1.06 (95% CI 0.91, 1.23), and 0.81 (95% CI 0.62, 1.05), respectively. When restricting to women without a history of subfertility, results were consistent for long post-partum interval and attenuated for short post-partum interval. CONCLUSIONS: Among North American pregnancy planners, long post-partum intervals (≥48 months) were associated with slightly reduced fecundability. Short post-partum intervals (<12 months) were weakly associated with reduced fecundability in some subgroups including women with a history of caesarean delivery and planned pregnancies.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.006 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one teacher head, not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".