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Mode of Conception and Risk of Spontaneous vs. Provider-Initiated Preterm Birth: Population-based cohort study
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  • Yimin Wang,
  • Joel Ray ,
  • Jessica Pudwell,
  • Laura Gaudet,
  • Yingwei Peng,
  • Maria Velez
Yimin Wang
Queen's University

Corresponding Author:[email protected]

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Joel Ray
Departments of Medicine and Obstetrics and Gynaecology, St. Michael’s Hospital, University of Toronto, Ontario, Canada
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Jessica Pudwell
Queen's University
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Laura Gaudet
Queen's University
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Yingwei Peng
Queen's University
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Maria Velez
Queen's University
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Abstract

Objective: To study the association between mode of conception and risk of preterm birth (PTB), including, spontaneous and provide-initiated PTB. Design: Retrospective cohort study Setting and Population: Population-based cohort included all singleton livebirths and stillbirth in Ontario, Canada, 2006-2014. Methods: Mode of conception comprised (i) subfertility without infertility treatment (N = 68,822); (ii) non-invasive infertility treatment (ovulation induction +/- intrauterine insemination) (N = 9024); or (iii) Invasive infertility treatment (in vitro fertilization [N = 8038) – each compared to births by unassisted conception (N = 646,926). Modified Poisson regression generated risk ratios (RR). Confounding was handled by inverse probability of treatment weighting using a propensity that included maternal demographics and pre-existing conditions. Main Outcome Measure: PTB < 37 completed weeks’ gestation. PTB was further categorized as spontaneous PTB or provider-initiated PTB. Results: PTB occurred among 6.0% of births by unassisted conception, 7.7% with subfertility, 8.0% with non-invasive infertility treatment, and 10.8% following invasive infertility treatment. The RR of provider-initiated PTB was higher in women with subfertility (RR 1.23, 95% CI 1.16-1.31), non-invasive infertility treatment (RR 1.48, 1.29-1.69) and invasive infertility treatment (RR 2.35, 2.09-2.64) – each relative to births by unassisted conception. The corresponding RR for spontaneous PTB were 1.15 (95% CI 1.10-1.19), 1.19 (95% CI 1.09-1.31) and 1.40 (95% CI 1.27-1.53). Conclusions: Subfertility, and receipt of infertility treatment, are each associated with a higher risk of PTB, especially provider-initiated PTB. Strategies are needed to reduce the underlying indications to deliver these women before term.
23 Jan 2022Submitted to BJOG: An International Journal of Obstetrics and Gynaecology
28 Jan 2022Submission Checks Completed
28 Jan 2022Assigned to Editor
11 Feb 2022Reviewer(s) Assigned
09 Mar 2022Review(s) Completed, Editorial Evaluation Pending
Nov 2022Published in Fertility and Sterility volume 118 issue 5 on pages 926-935. 10.1016/j.fertnstert.2022.07.028