Trends in Risk of Pregnancy Loss Among US Women, 1990-2011

Paediatr Perinat Epidemiol. 2018 Jan;32(1):19-29. doi: 10.1111/ppe.12417. Epub 2017 Oct 20.

Abstract

Background: Pregnancy loss can have physical and psychological consequences for women and their families. Though a previous study described an increase in the risk of self-reported pregnancy loss from 1970 to 2000, more recent examinations from population-based data of US women are lacking.

Methods: We used data from the 1995, 2002, 2006-2010, 2011-2015 National Survey of Family Growth on self-reported pregnancy loss (miscarriage, stillbirth, ectopic pregnancy) among US women (15-44 years) who reported at least one pregnancy conceived during 1990-2011 that did not result in induced termination (n = 20 012 women; n = 42 526 pregnancies). Trends in the risk of self-reported pregnancy loss and early pregnancy loss (<12 weeks) were estimated, separately, by year of pregnancy conception (limited to 1990-2011 to ensure a sufficient sample of pregnancies for each year and maternal age group) using log-Binomial and Poisson models, adjusted for maternal- and pregnancy-related factors.

Results: Among all self-reported pregnancies, excluding induced terminations, the risk of pregnancy loss was 19.7% and early pregnancy loss was 13.5% during 1990-2011. Risk of pregnancy loss increased by a relative 2% (rate ratio [RR] 1.02, 95% confidence interval [CI] 1.01, 1.02) per year in unadjusted models and 1% per year (RR 1.01, 95% CI 1.00, 1.02) during 1990-2011, after adjustment for maternal characteristics and pregnancy-related factors. In general, trends were similar for early pregnancy loss.

Conclusion: From 1990 to 2011, risk of self-reported pregnancy loss increased among US women. Further work is needed to better understand the drivers of this increase in reported pregnancy loss in the US.

Keywords: fetal loss; miscarriage; spontaneous abortion; stillbirth.

MeSH terms

  • Abortion, Spontaneous / epidemiology
  • Abortion, Spontaneous / etiology*
  • Adolescent
  • Adult
  • Continental Population Groups / statistics & numerical data
  • Female
  • Humans
  • Maternal Age
  • Poisson Distribution
  • Pregnancy
  • Retrospective Studies
  • Risk Factors
  • Socioeconomic Factors
  • United States / epidemiology
  • Young Adult