Bleeding, nausea at 6–8 weeks’ gestation predict pregnancy loss

The risk of clinical pregnancy loss is higher among women who experience vaginal bleeding without nausea between 6 and 8 weeks of gestation, a study has found. Prior to 6 weeks’ gestation, bleeding and nausea are not predictive of clinical pregnancy loss.

The Effects of Aspirin in Gestation and Reproduction trial (2006–2012) preconceptionally enrolled 701 women with clinically confirmed pregnancies and one to two previous pregnancy losses. Participants completed daily symptom diaries from 2 to 8 weeks of pregnancy and were prospectively monitored for detection of pregnancy loss.

The authors estimated the risk of pregnancy loss for each observed bleeding and nausea pattern and calculated positive and negative predictive values for each pattern.

Of the 701 women, 639 (91.2 percent) reported any nausea and 211 (30.1 percent) any vaginal bleeding, most of which was spotting and contained within a single episode.

Vaginal bleeding occurred in 5.9 percent of women (5.7 percent live birth; 7.1 percent clinical pregnancy loss within 2 to <4 weeks’ gestation, 14.6 percent (13.9 live birth; 18.6 percent clinical pregnancy loss) within 4 to <6 weeks’ gestation, and 20.8 percent (18.4 percent live birth; 32.4 percent clinical pregnancy loss) within 6 to 8 weeks’ gestation.

Within the same gestational periods, nausea was reported in 22.7 percent of women (23.2 percent live birth; 20.4 percent clinical pregnancy loss), 65.9 percent (67.5 percent live birth; 58.4 percent clinical pregnancy loss), and 87.0 percent (90.6 percent live birth; 69.0 percent clinical pregnancy loss).

Women experiencing bleeding without nausea between 6 and 8 weeks’ gestation (3.6-percent prevalence) were at highest risk of clinical pregnancy loss (risk difference, 56.1 percent, 95 percent confidence interval [CI], 37.6–74.7), with a positive predictive value of 68.0 percent (95 percent CI, 49.7–86.3), negative predictive value of 85.8 percent (95 percent CI, 83.2–88.4), positive likelihood ratio of 11.1 (95 percent CI, 2.04–20.1), and negative likelihood ratio of 0.86 (95 percent CI, 0.79–0.93).

Nausea and bleeding correlated with an increased risk of clinical pregnancy loss (area under the curve, 0.87, 95 percent CI, 0.81–0.88), as did age, body mass index, blood pressure, and waist-to-hip ratio (area under the curve, 0.81, 95 percent CI, 0.78–0.88) measured preconceptionally.