Prognostic value of ambulatory blood pressure measurements for the diagnosis of hypertension in pregnancy

Abstract

Several studies have indicated that the use of the 24 h mean blood pressure, mainly using reference thresholds derived from general nonpregnancy practice, does not provide an effective test for an individualized early diagnosis of hypertension in pregnancy, thus concluding that ambulatory blood pressure monitoring is not a valid approach in pregnancy. With the use of ambulatory blood pressure monitoring, epidemiologic studies have reported gender differences in the circadian variability of blood pressure and heart rate. Typically, men exhibit a lower heart rate and higher blood pressure than women, the differences being larger for systolic than for diastolic blood pressure. Moreover, normotensive and hypertensive pregnant women are characterized by differing but predictable patterns of blood pressure variability throughout gestation. However, the diminished blood pressure in nongravid women as compared with men, the added decrease in blood pressure during the second trimester of gestation in normotensive but not in hypertensive pregnant women and the large amplitude of the circadian pattern that characterizes the blood pressure of healthy pregnant women at all gestational ages, have not been taken into account when establishing reference thresholds for the diagnosis of hypertension in pregnancy. This review will describe these issues, summarize previous results from independent groups on the prognostic value of ambulatory blood pressure monitoring in pregnancy, propose answers as to an accurate reference threshold for blood pressure at different stages of gestation and suggest how this information should be used in order to identify those women at a higher risk of hypertension, who will also be more suitable for prophylactic and/or therapeutic intervention in the early stages of pregnancy.

Ambient Air Pollution and Pregnancy-Induced Hypertensive Disorders

“…[10][11][12][13][14][15][16][17][18][21][22][23][24][25][26][27] All studies with the exception of 1 case-control study 28 were prospective cohorts or birth record-based retrospective cohorts. The studies were based on 298 to 468 517 pregnancies occurring during 1996 to 2008.…”

“…5 In healthy pregnancies, the blood pressure falls during the first trimester, reaching its lowest levels in midpregnancy, and then it increases to prepregnancy levels by term, whereas for women who develop gestational hypertension or preeclampsia blood pressure is stable during the first half of pregnancy and then increases until delivery. 28 A few studies have examined associations between air pollution and blood pressure in pregnant women.…”

“…5 In healthy pregnancies, the blood pressure falls during the first trimester, reaching its lowest levels in midpregnancy, and then it increases to prepregnancy levels by term, whereas for women who develop gestational hypertension or preeclampsia blood pressure is stable during the first half of pregnancy and then increases until delivery. 28 A few studies have examined associations between air pollution and blood pressure in pregnant women. 24,[29][30][31] Differences in design and exposure periods make comparisons between these studies difficult; however, the findings from these studies suggest that exposure to air pollutants during pregnancy increases blood pressure.…”

Additive value of standard ECG for the risk prediction of hypertensive disorders during pregnancy

“…It is well recognized that a relatively large proportion of pregnant women may have masked gestational hypertension, undetected by office BP measurements, but revealed by specific BP index or circadian patterns computed with ambulatory BP monitoring. [31][32][33] Notably, pregnant women at increased risk of hypertension disorders tend to have higher night-time ambulatory BP than women without development of hypertension complications during pregnancy. 33 At the same time, night-time ambulatory BP is an independent predictor of LA size in hypertensive patients.…”

Blood Pressure Changes during Pregnancy: Impact of Race, Body Mass Index, and Weight Gain

“…The absence of normal vascular adjustment to pregnancy has been associated with complications such as hypertension and preeclampsia in late pregnancy. [9][10][11] Blood pressure in healthy pregnant women decreases through weeks 20 to 26 of gestation, then steadily increases by 7 to 10% of the nadir until delivery, with blood pressure returning to baseline postpartum. Women who do not exhibit this physiological nadir but rather maintain a stable blood pressure in the first half of pregnancy and steadily increase until delivery have higher rates of pregnancy-induced hypertension and preeclampsia and higher rates of hypertension and ischemic heart disease later in life.…”