Risk factors of early and late onset pre‐eclampsia

AIMS: The aim of this study was to identify the differences in risk factors between early and late onset pre-eclampsia. MATERIAL AND METHODS: A case-control study was carried out involving pregnancies with pre-eclampsia (152 early onset and 297 late onset) and 449 controls at King Chulalongkorn Memorial Hospital, Bangkok, Thailand between 1 January 2005 and 31 December 2010. The data were reviewed from antenatal and delivery records. RESULTS: Factors which were significantly associated with increased risk for both early and late onset pre-eclampsia were family history of diabetes mellitus, high pre-pregnancy body mass index ≥ 25 kg/m(2) and weight gain ≥ 0.5 kg per week. History of chronic hypertension (odds ratio 4.4; 95% confidence interval 2.1-9.3) was significantly associated with increased risk for only early onset pre-eclampsia, while family history of chronic hypertension (odds ratio 18; 95% confidence interval 6-54) was significantly associated with increased risk for only late onset pre-eclampsia. CONCLUSIONS: The risk factors that differ between early and late onset of pre-eclampsia were history of chronic hypertension and family history of chronic hypertension. Family history of diabetes mellitus, pre-pregnancy body mass index ≥ 25 kg/m(2) and weight gain ≥ 0.5 kg per week were risk factors of both early and late onset pre-eclampsia. These risk factors are of value to obstetricians in identifying patients at risk for pre-eclampsia and in implementing primary prevention.