The effects of mild hypertension in early pregnancy on gestational diabetes mellitus

Background Gestational diabetes mellitus（GDM） often results in perinatal complications.Women with GDM are prone to have postpartum diabetes,and metabolic syndrome including hypertension years after delivery.It is unclear if mild hypertension in early pregnancy contributes to GDM.Objective To examine the relationship between blood pressure during early pregnancy and the risk of GDM in a cohort study.Methods One thousand two hundred and twenty-one pregnant patients were selected from a cohort of women delivering one live baby from our department between 2007 and 2010.Patients were categorized according to blood pressure in early pregnancy as normal（less than 120/80 mm Hg） n=605,the age（28.6±2.8）years,prehypertensive systolic blood pressure（SBP） from 120 to 139 mm Hg or diastolic blood pressure（DBP） from 80 to 89 mm Hg,n=494,the age（28.3±2.6）years and mild hypertension SBP from 140 to 149 mm Hg or DBP from 90 to 99 mm Hg,n=122,the age（28.8±2.8）years groups.The prevalences of GDM among the groups were compared using chi-square test and partitions of chi-square method.The relationship between blood pressure levels and GDM was evaluated by Logistic regression analyses.Results GDM occurred in 97 patients（prevalence was 7.9%）.The proportions of GDM in mild hypertensive,prehypertensive and normal group were 24.6%,9.1% and 3.6% respectively.There were significant differences in incidences among those groups according to the chi-square test（chi-square value was 62.493,P＜0.01） and partitions of chi-square method（mild hypertensive vs normal,mild hypertensive vs prehypertensive and prehypertensive vs normal,the chi-square values were 67.122,21.928 and 14.229 respectively,all P＜0.01）.When compared to patients with normal blood pressure,women with prehypertension or mild hypertension during early pregnancy had an increased risk of GDM（odds ratio 2.1） using patients Logistic regression analysis（chi-square value was 103.298,P＜0.01）.In addition,pregnant patients with maternal type 2 diabetes mellitus, or with high body mass index are more likely to get to GDM（odds ratio 3.5 and 2.6 respectively）.Conclusion These findings indicate that as blood pressure levels in the early pregnancy rise,pregnant patients may have increased risk of developing GDM.The early screening and treatment of pregnant hypertension may reduce the rate of developing GDM.