History of oral contraceptive use and risk of spontaneous abortion

Predictive models of miscarriage on the basis of data from a preconception cohort study

OBJECTIVE

To use self-reported preconception data to derive models that predict the risk of miscarriage.

DESIGN

Prospective preconception cohort study.

SETTING

Not applicable.

PATIENTS

Study participants were female, aged 21-45 years, residents of the United States or Canada, and attempting spontaneous pregnancy at enrollment during 2013-2022. Participants were followed for up to 12 months of pregnancy attempts; those who conceived were followed through pregnancy and postpartum. We restricted analyses to participants who conceived during the study period.

EXPOSURE

On baseline and follow-up questionnaires completed every 8 weeks until pregnancy, we collected self-reported data on sociodemographic factors, reproductive history, lifestyle, anthropometrics, diet, medical history, and male partner characteristics. We included 160 potential predictor variables in our models.

MAIN OUTCOME MEASURES

The primary outcome was a miscarriage, defined as pregnancy loss before 20 weeks of gestation. We followed participants from their first positive pregnancy test until miscarriage or a censoring event (induced abortion, ectopic pregnancy, loss of follow-up, or 20 weeks of gestation), whichever occurred first. We fit both survival and static models using Cox proportional hazards models, logistic regression, support vector machines, gradient-boosted trees, and random forest algorithms. We evaluated model performance using the concordance index (survival models) and the weighted F1 score (static models).

RESULTS

Among the 8,720 participants who conceived, 20.4% reported miscarriage. In multivariable models, the strongest predictors of miscarriage were female age, history of miscarriage, and male partner age. The weighted F1 score ranged from 73%-89% for static models and the concordance index ranged from 53%-56% for survival models, indicating better discrimination for the static models compared with the survival models (i.e., the ability of the model to discriminate between individuals with and without miscarriage). No appreciable differences were observed across strata of miscarriage history or among models restricted to ≥8 weeks of gestation.

CONCLUSION

Our findings suggest that miscarriage is not easily predicted on the basis of preconception lifestyle characteristics and that advancing age and a history of miscarriage are the most important predictors of incident miscarriage.

Preconception contraceptive use and miscarriage: prospective cohort study

Objectives

To evaluate the association between preconception contraceptive use and miscarriage.

Design

Prospective cohort study.

Setting

Residents of the United States of America or Canada, recruited from 2013 until the end of 2022.

Participants

13 460 female identified participants aged 21-45 years who were planning a pregnancy were included, of whom 8899 conceived. Participants reported data for contraceptive history, early pregnancy, miscarriage, and potential confounders during preconception and pregnancy.

Main outcome measure

Miscarriage, defined as pregnancy loss before 20 weeks of gestation.

Results

Preconception use of combined and progestin-only oral contraceptives, hormonal intrauterine devices, copper intrauterine devices, rings, implants, or natural methods was not associated with miscarriage compared with use of barrier methods. Participants who most recently used patch (incidence rate ratios 1.34 (95% confidence interval 0.81 to 2.21)) or injectable contraceptives (1.44 (0.99 to 2.12)) had higher rates of miscarriage compared with recent users of barrier methods, although results were imprecise due to the small numbers of participants who used patch and injectable contraceptives.

Conclusions

Use of most contraceptives before conception was not appreciably associated with miscarriage rate. Individuals who used patch and injectable contraceptives had higher rates of miscarriage relative to users of barrier methods, although these results were imprecise and residual confounding was possible.

Pregravid Oral Contraceptive Use and the Risk of Preterm Birth, Low Birth Weight, and Spontaneous Abortion: A Systematic Review and Meta-Analysis

Background: Although oral contraceptives (OCs) have been widely used by women of childbearing age, their influence on pregnancy and birth outcomes, such as preterm birth (PB), low birth weight (LBW), and spontaneous abortion (SAB), is unclear. The aim of this systemic review was to assess these complications in women who had used OCs before pregnancy compared with those in a control group. Materials and Methods: The databases of PubMed, EMBASE, and Web of Science were searched up to December 2018. We included studies where the primary outcome was the risk of PB, LBW, and SAB in women with pregravid OCs use compared with the control group. Odds ratio (OR) value was calculated to assess the risk. Results: Eighteen studies were included in the systematic review, and a total of 148,406 subjects from 7 studies were pooled for the meta-analysis. Results showed that the risk of PB was slightly higher in the exposed group (OR = 1.17, 95% confidence interval [CI] = 1.07-1.27, p = 0.0005); however, there was a lower risk for SAB compared with the control group (OR = 0.63, 95% CI = 0.41-0.96, p = 0.03). No significant difference was found in the incidence of LBW (OR = 1.36, 95% CI = 0.92-2.02, p = 0.12). Conclusions: This systematic review and meta-analysis demonstrated a higher risk for PB and a lower risk for SAB in women with previous ORs use, whereas no association was found between ORs use and LBW risk.