Incidence and Predictors of Chronic Hypertension Following Hypertensive Disorders in Pregnancy at Kenyatta National Hospital,(a Descriptive Prospective Cohort Study)

Abstract

Introduction: Hypertensive disorders in pregnancy complicate up to 10% of pregnancies worldwide, constituting one of the greatest causes of maternal and perinatal morbidity and mortality. In Kenya, studies conducted at Kenyatta National Hospital have noted a prevalence of 5.4% of hypertensive disease and 0.56% for eclampsia. Hypertension in pregnancy usually resolves after delivery. If it persists, it leads to chronic hypertension which in itself is an important risk factor in cardiovascular disease. Objective: To determine the incidence and risk factors of chronic hypertension, and time to resolution of hypertension among patients with gestational hypertension and preeclampsia-eclampsiaseen at KNH up to 12 weeks postpartum. Methodology: This was a prospective descriptive cohort study carried out at Kenyatta National Hospital, Nairobi, Kenya. The study had one hundred and sixteenparticipants with hypertensive disorders in pregnancywho were followed up until 12 weeks postpartum. Data were collected via interviewer-administered questionnaires, serial blood pressure measurements and review of medical records. They were then analyzed using SPSS IBM (Version 21). Categorical variables were subjected to the chi-square test, while continuous variables were compared using Student’s t-test. Risk factors for persistence of hypertension underwent bivariate analysis. A p value<0.05 was considered statistically significant. Results: A quarter of the study participants were still hypertensive at the end of puerperium. Among these, 30% developed chronic hypertension. The risk factors associated with development of chronic hypertension among these parturients were higher pre-pregnancy BMI (OR=19.4, 95% CI 2.0-187.9, p=0.02), intimate partner violence(OR=2.5, 95% CI 1.0-6.1, p=0.036), lower gestational age at delivery(OR=2.6, 95% CI 1.1-6.2, p=0.035), lower gestational age at onset of hypertension(OR=2.4, 95% CI 1.1-5.7, p=0.038), family history of hypertension(OR=3.0, 95% CI 1.2-7.5, p=0.015), personal history of diabetes mellitus (OR=4.8, 95% CI 1.5-15.4, p=0.008), and thrombocytopenia (OR=2.8, 95% CI 1.1-7.3, p=0.013). Obesity was the only significant risk factor in both univariate and multivariate analysis. The time to resolution of hypertension was found to be 2 weeks postpartum for majority of the patients (57.8%). Conclusion: Hypertension in pregnancy is a significant risk factor for developing persistent and chronic hypertension after delivery. Timely diagnosis and timely appropriate intervention are the key strategies to reduce the risk of developing future cardiovascular morbidity. Recommendations: Women with hypertensive disorders in pregnancy should be followed up beyond 6 weeks postpartum and should be counseled on the risk of developing chronic hypertension.