Nausea and vomiting were associated with a reduced risk of pregnancy loss among women who have had 1 or 2 prior pregnancy losses, according to a study published in JAMA Internal Medicine.
Enrique F. Schisterman, PhD, Division of Intramural Population Health Research, Eunice Kennedy Shriver National Institute of Child Health and Human Development, and colleagues examined the association of nausea and vomiting during pregnancy in women enrolled in the Effects of Aspirin in Gestation and Reproduction trial.
The trial included 797 women (mean age, 28.7 years) with at least 1 or 2 prior pregnancy losses at 4 clinical centers from June 2007 to July 2011. The researchers limited their secondary analysis to include women with a pregnancy confirmed by a human chorionic gonadotropin (hCG) test. The primary outcome of the study was peri-implantation and clinically recognized pregnancy losses.
The investigators obtained data regarding nausea symptoms from daily preconception and pregnancy diaries maintained from gestational weeks 2 through 8. The women also completed monthly questionnaires from weeks 12 to 36 that summarized nausea symptoms.
“A unique aspect of our study was the inclusion in analytic models of rarely studied fetal factors that may contribute to variation in nausea symptoms through their effect on hCG levels and thus affect pregnancy loss; notably, our findings related to clinical pregnancy loss persisted after accounting for these factors,” the study authors wrote. “Another possibility is that nausea and vomiting are markers for viable placental tissue. Thus, less nausea and vomiting may identify failing pregnancies, with lower hormone levels leading to nausea and vomiting.”
The results showed that 23.6% of the pregnancies ended in loss. After 2 gestational weeks, 17.8% of women reported nausea without vomiting and 2.7% reported nausea with vomiting. After 8 gestational weeks, 57.3% of women reported nausea without vomiting and 26.6% reported nausea with vomiting.
Nausea alone and nausea with vomiting were inversely associated with pregnancy loss (hazard ratios [HRs], 0.50 and 0.25, respectively). The investigators observed a similar association with peri-implantation losses, but these results were not statistically significant (HR for nausea alone, 0.59; HR for nausea with vomiting, 0.51). Nausea and nausea with vomiting were associated with a lower risk of pregnancy loss (HR, 0.44 and 0.20, respectively).
“These findings overcome prior analytic and design limitations and represent the most definitive data available, to our knowledge, indicating the protective association of nausea and vomiting in early pregnancy on the risk for pregnancy loss and thus may provide reassurance to women experiencing these difficult symptoms in pregnancy,” the authors concluded.
- Hinkle SN, Mumford SL, Grantz KL, et al. Association of nausea and vomiting during pregnancy with pregnancy loss. JAMA Intern Med. 2016; doi: 10.1001/jamainternmed.2016.5641.