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

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.