Aim: To assess cardiac diastolic function by echocardiography in pregnancies complicated by hypertensive disorders and in normotensive pregnant women, correlate the severity of hypertensive disorders in pregnancy with the severity of cardiac diastolic dysfunction, and determine if cardiac diastolic dysfunction assessed by echocardiography can be used as a prognostic tool for the severity of hypertensive disorders in pregnancy with regard to heart failure. Methodology: This is an observational comparative study conducted on 160 singleton pregnant women between 20 and 40 weeks of gestation over a period of 6 months and 160 subjects are placed in two groups—80 in hypertensive group and 80 in normotensive group. Transthoracic Doppler echocardiography is carried out on these patients and cardiac diastolic dysfunction grading is done per echocardiographic guidelines of the American Society. Results: In this study, all the normotensives had normal diastolic function (100%) whereas a significant percentage (32%) of the subjects in the hypertensive group had diastolic dysfunction (p-value < 0.0000001). There is no significant association between the severity of hypertensive disorders with the severity of diastolic dysfunction of p-value 0.2. Conclusion: A significant percentage of subjects in the hypertensive group had diastolic dysfunction when compared to the normotensive group. Thus, diastolic function by Doppler echocardiography may be a good prognostic tool in hypertensive disorders of pregnancy so that early admission, continuous monitoring, and planned delivery can be instituted to prevent cardiac complications like heart failure.