Fully 41.5% of women with severe preeclampsia had hypertension on ambulatory blood pressure monitoring 1 year after delivery, researchers found.
Masked hypertension — defined in the study by closer to what is now the threshold for stage 2 hypertension, 135/85 mm Hg at home — was the most common (17.5%), followed by sustained hypertension (14.5%) and white coat hypertension elevated only in the clinic (9.5%).
Fewer than a quarter of these women would have been diagnosed as hypertensive with office blood pressure measurement alone, Laura Benschop, MD, of Erasmus Medical Center in Rotterdam, The Netherlands, and colleagues reported in Hypertension.
“Optimal timing and type of screening in the postpartum period for women with preeclampsia is not yet totally clear, and is an area of very active research,” Kristen Cleary, MD, of NewYork Presbyterian/Columbia University Irving Medical Center in New York City and who was not involved in the research, said in a statement. “These women should be followed on a regular basis after delivery for high blood pressure, and primary care doctors should be aware of this important issue in their patients’ medical history.”
Benschop and colleagues noted that recent studies found women with preeclampsia often have hypertension after pregnancy, which contributes to cardiovascular disease and stroke risk. While prior studies measured only office blood pressure to determine preeclampsia and hypertension, they said that ambulatory blood pressure monitoring, using a small machine to be worn on a belt for 24 hours, is the “gold standard” to rule out either masked hypertension or white coat hypertension and assess for a dipping pattern, or the systolic night-to-day blood pressure ratio.
“Sustained hypertension, masked hypertension, [white coat hypertension] and a disadvantageous dipping pattern are all independent risk factors for future [cardiovascular disease] and therefore clinically important,” the authors wrote.
Researchers examined 200 women with a history of severe preeclampsia, who met several pre-specified criteria, including systolic blood pressure ≥160 mm Hg or diastolic blood pressure ≥110 mm Hg on two occasions at least 6 hours apart and proteinuria ≥5 g per 24 hours or ≥3+ on two urine samples collected at least 4 hours apart.
They were followed for 1 year after pregnancy and had 24-hour blood ambulatory blood pressure monitoring, as well as an office blood pressure measurement between 9 and 15 months after delivery.
Study participants were a mean of 31.6 years old, and 70% were nulliparous. Three-quarters of women were diagnosed with early-onset preeclampsia, with an average gestational age at diagnosis of 30.5 weeks. A little under 70% of infants born to the group were small for gestational age.
The authors also noted that 15.7% of women had moderately-increased albuminuria, a symptom of kidney disease, while 3.4% of women had severely-increased albuminuria a year after pregnancy.
About 20% of women were already receiving treatment for previously-diagnosed hypertension. About 55% of women with sustained hypertension had been diagnosed with hypertension prior to ambulatory blood pressure monitoring, as well as 31.4% of women with masked hypertension and 47.4% of women with white coat hypertension. Moreover, three-quarters of women who were diagnosed with hypertension prior to ambulatory blood pressure monitoring did not “receive optimal antihypertensive drug treatment” or were non-adherent to it.
In addition, 45.5% of women had a risk-associated pattern of systolic night-to-day blood pressure ratio dipping, and “this percentage was equal between women with a normotensive and hypertensive daytime ambulatory blood pressure monitoring,” the authors said.
Limitations to the data included the descriptive design of the study, which meant that differences in hypertension prevalence and dipping pattern between women with previous preeclampsia and those with a previous normotensive pregnancy or other gestational hypertension disorder could not be examined. The researchers also noted findings may not be generalizable to all women and noted the portion of women with albuminuria, which has the tendency to affect blood pressure.
The authors disclosed no conflicts of interest.