People with no history of high blood pressure can develop hypertension for the first time in the weeks and months after childbirth, but there is very little data on first-time hypertension that develops more than six weeks after delivery.
Now, a new study led by a Boston University School of Public Health (BUSPH) researcher has found that 1 in 10 women who did not have hypertension before or during pregnancy may develop hypertension up to a year after they give birth.
Published in Hypertension, a journal of the American Heart Association, the study also found that nearly a quarter of these cases of high blood pressure developed six weeks or more after childbirth, and mothers at highest risk are over 35 years old, current or former smokers, or patients who delivered their baby via Cesarean section.
The new study, which featured racially and ethnically diverse participants, shows that patients with all three of the above risk factors had a 29 percent risk of developing new postpartum hypertension, and that this risk increased to 36 percent among non-Hispanic Black patients.
For the study, researchers from BUSPH and Boston University Chobanian & Avedisian School of Medicine (Chobanian & Avedisian SOM) utilized medical records to examine demographic characteristics and prenatal, delivery, and postpartum data among 3,925 pregnant people who gave birth between 2016 and 2018 at Boston Medical Center. The researchers analyzed patients’ blood pressure measurements from the prenatal period through 12 months after delivery, taken at the hospital during office visits, urgent and emergency care, and readmissions.
The team defined new-onset postpartum hypertension as at least two separate blood pressure readings, beginning 48 hours after delivery, in which the systolic blood pressure was at least 140 mmHg and the diastolic blood pressure was at least 90 mmHg. Severe blood pressure included systolic readings that were at least 160 mmHg and diastolic readings that were at least 110 mmHg.
Although the majority of patients were diagnosed with postpartum hypertension before they were discharged from the hospital following delivery, 43 percent of patients received first-time hypertension diagnoses after their delivery hospitalization—and about half of these new cases occurred more than six weeks postpartum, emphasizing the need for blood pressure monitoring throughout the entire postpartum period.
