Preterm birth and secondhand smoking during pregnancy: A case-control study from Vietnam

The relationship between women who are exposed to secondhand smoke and preterm birth is still controversial. The present study aimed to examine the association between maternal secondhand smoking (SHS) during pregnancy and preterm birth. A 1:1 case-control study was conducted at delivery room of The Women's and Children's Hospital of An Giang, Vietnam. A total of 288 cases of preterm birth and 288 controls included in this study. A structured questionnaire in a face-to-face interview was used to assess SHS and potential confounders (maternal age, body mass index, occupation, education level, parity, antenatal care visits, history of preterm birth, prenatal bleeding and preeclampsia/eclampsia). SHS was reported more frequently by women who delivered preterm babies compared with women of term deliveries (67.4% vs. 51.0%; P