Maternal pre-pregnancy risk factors for miscarriage from a prevention perspective: a cohort study in China

To assess the relationship of the pre-pregnancy modifiable risks with miscarriage.

We randomly selected 51 communities or villages from January 2013 to December 2014 in Anhui, China. We calculated incidence rate ratios (RR) and 95% confidence intervals (CIs) for each risk factor for miscarriage.

The incidence rate of miscarriage was 7.45%, and pre-embryonic loss account for 12.66%, embryonic loss account for 38%, and fetal losses account for 49.34% of all loss. In multivariate analysis, women with hypertension (RR=2.272, 95% CI=1.27-4.04), women had a family history of abortion in their mother (RR=1.96, 95% CI=1.22-3.14) prior to pregnancy had significantly higher adjusted risk ratio for miscarriage. Obese, overweight, and underweight prior to pregnancy were about 2.01 (95% CI=1.1-3.68), 1.71 (95% CI=1.04-2.81), and 2.05 (95% CI=1.3-3.23) times more likely to end in miscarriage compared with normal weight. Some physical examination indicators, for example pH value of leucorrhea ≥4.5 (RR=2.13, 95% CI=1.48-3.07), red blood cell count <5 10(12)/L (RR=1.52, 95% CI=1.02-2.26), and positive LgG antibodies to human cytomegalovirus (RR=1.45, 95% CI=1.02-3.14) prior to pregnancy had good prediction effect on miscarriage. We also found remarkable differences on risk factors between non-fetal losses and fetal losses.

Our results suggest that these modifiable risks should be included into pre-conception counseling as important risk factors for screening high-risk population and reducing the rate of spontaneous abortion.