ArticleEpidemiology (Cambridge, Mass.)2022
A Prospective Cohort Study of Seasonal Variation in Spontaneous Abortion.
Article in Epidemiology (Cambridge, Mass.), 2022. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 9 papers.
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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
9 citing papers in PubMed.
- Patient-Reported Experiences of Abortion Travel.JAMA network open · 2026Article
- Unintended pregnancy and induced abortion in Sierra Leone: abortion incidence complications method-based estimates.BMC public health · 2026Article
- Association between embryo transfer season and the risks of hypertensive disorders of pregnancy and gestational diabetes mellitus.Journal of assisted reproduction and genetics · 2025Article
- Analysis of the implementation value of abdominal B-ultrasound combined with cervical cerclage in the prevention and treatment of late recurrent spontaneous abortion.BMC pregnancy and childbirth · 2024Article
- Seasonal Variations in Birth Patterns in Greece: A Comprehensive Analysis of National Data From 1956 to 2022.Cureus · 2024Article
- Exposure to Ambient Heat and Risk of Spontaneous Abortion: A Case-Crossover Study.Epidemiology (Cambridge, Mass.) · 2024Article
- Ambient air pollution and rate of spontaneous abortion.Environmental research · 2024Article
- Polyploidy Phenomenon as a Cause of Early Miscarriages in Abortion Materials.Balkan journal of medical genetics : BJMG · 2023Article
- The risk of miscarriage is associated with ambient temperature: evidence from coastal Bangladesh.Frontiers in public health · 2023Article
Corrections and comments
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Authors and funding
7 authors.
Funding
Abstract
backgroundUp to 30% of pregnancies end in spontaneous abortion, yet few risk factors have been identified. Examining seasonal patterns in risk of spontaneous abortion can generate new hypotheses regarding environmental and lifestyle determinants.
methodsWe used data from Pregnancy Study Online-a preconception cohort study of pregnancy planners from the United States and Canada-to examine seasonal variation in spontaneous abortion risk. We enrolled 12,197 women during 2013 to 2020, 6104 of whom reported a conception within 12 months of enrollment. On follow-up questionnaires, participants reported date of spontaneous abortion and weeks gestation at time of loss. We used periodic regression to estimate two aspects of seasonal occurrence: peak/low ratio-a measure of intensity of seasonal variation-and peak timing. We examined season at risk (from the date of each gestational week) in relation to spontaneous abortion; in a secondary analysis, we examined season of conception in relation to spontaneous abortion. We controlled for seasonal patterns in attempt initiation via month the pregnancy attempt began.
resultsAlmost 20% of women experienced spontaneous abortion. Risk was highest in late August, with a peak/low ratio of 1.3 (95% confidence interval [CI] = 1.1, 1.6). This seasonal pattern was evident almost exclusively for spontaneous abortion at <8 weeks since the last menstrual period date (peak/low ratio = 1.4; 95% CI = 1.2, 1.8), and associations were stronger among women living in the Southern and Midwestern United States.
conclusionsEnvironmental or lifestyle factors more prevalent in late summer may be associated with increased risk of early spontaneous abortion.
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