Risk factors for early miscarriage among Chinese: a hospital-based case-control study

Objective To investigate the risk factors for early miscarriage among Chinese women. Design Hospital-based matched case-control study. Setting Academic medical center and maternal health hospital. Patient(s) 620 women with early miscarriage (less than 13 weeks of gestation) and 1,240 normal pregnant women. Intervention(s) Face-to-face questionnaire. Main Outcome Measure(s) Multivariable conditional odds ratio (OR) and 95% confidence interval (CI) to measure risk factors. Result(s) After adjustment for confounding factors, the following were independently associated with increased risk: history of miscarriage, repeated induced abortion, working night shifts, and frequent staying up late. Vitamin supplementation and regular physical activity reduced the risk of miscarriage. We did not find paternal age, alcohol consumption, or smoking status to be linked with early miscarriage. Conclusion(s) Our findings suggest that a healthy diet, regular physical activity, and planned pregnancy may be advantageous for women in pre-pregnancy or early pregnancy. Induced abortion, working night shifts, and frequent staying up late were associated with an increased risk of miscarriage. Further work in larger populations is warranted.