Fig. 4

Association between month of conception with preterm birth (A) and early preterm birth (B). *Adjusted for demographic characteristics (age, ethnicity, education level and occupation), reproductive characteristics (first gestation, primipara, history of preterm birth, history of spontaneous abortion, history of induced abortion and history of stillbirth), health status (BMI, anemia and HBsAg) and living habits during pregnancy (eating meat and eggs, no eating vegetables, smoking, drinking alcohol and taking folic acid)