Chronic Hypertension In Pregnancy Research Articles

Chronic hypertension in pregnancy: Focus on clinical management

Chronic hypertension in pregnancy: Focus on clinical management

Diagnosis and management of chronic hypertension in pregnancy

Pregnancies complicated by chronic hypertension are at increased risk for the development of superimposed preeclampsia, abruptio placentae, and poor perinatal outcome. The frequency of these complications is particularly increased in patients with severe hypertension and those with preexisting cardiovascular and renal disease. Such women should receive appropriate antihypertensive therapy and frequent evaluations of maternal and fetal well-being. In contrast, in patients with mild essential chronic hypertension, the maternal and perinatal benefits from antihypertensive medications are highly controversial. A review of the literature revealed two placebo-controlled studies, four trials comparing treatment versus no medication, and three comparisons of methyldopa and oxprenolol. In only one of these studies were subjects randomized in the first trimester. No differences in pregnancy outcome were found with the use of antihypertensive drugs. Evaluation of the woman with chronic hypertension who is considering pregnancy should begin before conception to establish the cause and severity of the hypertension. Appropriate management should include frequent evaluation of maternal and fetal well-being; antihypertensive medications may be useful in patients with severe disease as well as in those with target organ involvement.

Renin-angiotensin-aldosterone system in normal and hypertensive pregnancy. Response to postural stimuli.

Most studies that have attempted to distinguish pregnancy-induced hypertension from chronic hypertension in pregnancy include arbitrary clinical definitions and morphological reports based on renal biopsy. To evaluate whether these conditions have different responses to stimuli to the renin-angiotensin-aldosterone system, we studied four normal nonpregnant women, eight normal pregnant women, 10 women with pregnancy-induced hypertension, and 14 with chronic hypertension in pregnancy, in the third trimester of pregnancy, after they had sequentially adopted the supine, the left lateral recumbent, and the orthostatic positions for 90 minutes each. Postural maneuvers did not significantly change mean arterial pressure in pregnancy-induced hypertensive or in normal pregnant women, although in chronic hypertensive women, a significant reduction in this parameter was observed in left lateral recumbency. The renin-angiotensin-aldosterone system was significantly less activated with women in the supine position in pregnancy-induced hypertensive and chronic hypertensive women; however, as opposed to pregnancy-induced hypertensive women, those with chronic hypertension reassumed their humoral response to upright posture, which was accompanied by a significant reduction in sodium excretion. The parallelism between plasma renin activity and aldosterone levels, absent in normal pregnancy, returned in pregnancy-induced hypertensive and chronic hypertensive women in the erect posture (r = 0.73, p less than 0.01; r = 0.68, p less than 0.01, respectively). These data suggest that the adoption of the left lateral recumbent position in pregnancy reduces mean arterial pressure only in chronic hypertensive women. Moreover, in chronic hypertension, the upright position provoked a significant response of the renin-angiotensin-aldosterone system. This effect was not observed in women with pregnancy-induced hypertension.

Chronic Hypertension in Pregnancy

Women with chronic hypertension who are considering pregnancy should undergo extensive evaluation and work-up prior to conception. This evaluation is important to establish the cause and severity of the hypertension. The patient should be seen early in pregnancy and counseled regarding the possible adverse effects of hypertension and the importance of adherence to prenatal visits and prescribed medications. Patients classified to have high-risk hypertension are at increased risk for significant maternal and perinatal complications. These patients should have intensive antenatal follow-up and will require antihypertensive therapy irrespective of the severity of the hypertension. In contrast, in women with mild uncomplicated hypertension, good perinatal outcome is expected with proper obstetric care, without the use of antihypertensive drugs. Finally, most of the poor perinatal outcome in such pregnancies is related to the development of superimposed preeclampsia.

Controlled Trials of Antihypertensive Drugs in Pregnancy

It Is taken for granted that severe hypertension In pregnancy should be treated, although the principle has not been formally tested by properly controlled trials. There is less certainty about treating mild to moderate hypertension (140/90 to 169/109 mm Hg). The risk of chronic hypertension in pregnancy depends on that of superimposed preeclampsia, which must be prevented by control of the blood pressure if antihypertensive treatment is to be beneficial. There is no a priori reason why lowering the blood pressure should have this effect. Most of the trials of treatment have been too small to provide conclusive answers. Usually treatment has been started too late to give a realistic expectation of influencing the evolution of superimposed preeclampsia. However, the largest trial of the early use of methyldopa In women with mild chronic hypertension, showed clearly that treatment does not prevent the superimposition of preeclampsia. β-Adrenergic blocking agents, if used from the second start of the trimester, are associated with a major risk of severe growth retardation and are therefore contraindicated. Methyldopa has the best safety record, which includes long-term follow-up to assess the development of children exposed to methyldopa in utero. The ineffectiveness of antihypertensive drugs In preventing or ameliorating preeclampsia needs to be contrasted with the consistent evidence for the effectiveness of anti platelet therapy. This is consistent with the increasing evidence that preeclampsia is not primarily, or even necessarily, a hypertensive disease.

Glomerular dynamics and salt balance in pregnant rats with renal hypertension.

These studies were aimed at investigating whether chronic hypertension in pregnancy causes changes both in salt excretion (NaE) and in glomerular hemodynamics. Metabolic and renal micropuncture studies were performed in pregnant (P) and Virgin (V) Munich-Wistar rats with normal blood pressure (N) and two-kidney Goldblatt hypertension (H). Mean NaE was higher in PN than VN (2.7 vs. 1.7 meq/day, P less than 0.01). Hypertension raised NaE both in P and V rats: in P and V rats with "benign" hypertension (blood pressure less than 180 mmHg) NaE averaged 3.2 and 2.6 meq/day, respectively (P less than 0.05); mean NaE was 5.9 and 3.8 meq/day, respectively (P less than 0.01), in P and V rats with "malignant" hypertension (blood pressure greater than or equal to 180 mmHg). Afferent arteriole resistance (Ra) averaged 1.73 and 3.50 10 dyn.s-1.cm5 in PN and VN, respectively (P less than 0.01). Hypertension raised Ra in V, but not in P rats (4.47 vs. 2.14 10 dyn.s-1.cm5, P less than 0.01). Thus glomerular plasma flow, glomerular capillary hydrostatic pressure, and single-nephron glomerular filtration rate were markedly higher in PH than VH rats: in PH rats single-nephron filtration fraction was significantly lower than in VH. These results show that in PH rats a marked rise in NaE is associated with glomerular vasodilation.

Chronic hypertension in pregnancy

The course and outcome of 169 pregnancies in 156 women with chronic hypertension were studied. Antihypertensive medications were given if the diastolic blood pressure exceeded 90 mmHg. A number of major associated medical problems were found. Left ventricular hypertrophy, a serum creatinine greater than 1.0 mg%, and a diastolic pressure greater than 100 mmHg at less than 20 weeks' gestation were high-risk indicators. The overall perinatal mortality was 28.4 of 1000 (versus hospital of 25.6 of 1000). Despite antihypertensive therapy, one-third of the patients developed superimposed preeclampsia. The poorest outcome occurred in patients with superimposed preeclampsia necessitating delivery at 27 to 34 weeks' gestation (perinatal mortality = 238 of 1000). Antepartum fetal heart rate testing was abnormal in 10% of the patients with intrauterine growth retardation occurring in 15%. The incidence of fetal growth retardation was fourfold higher (20 versus 5%) in patients treated with antihypertensive drugs, particularly methyldopa as a single agent. However, this may have been related more to the study design than to a detrimental effect of the drug. The perinatal outcome in this study is similar to the outcome of studies in which antihypertensive therapy was withheld. This indicates that controlling the blood pressure is merely one aspect of the management of chronic hypertension in pregnancy. Accurate dating, attention to associated medical problems, antenatal fetal assessment by ultrasound and heart rate monitoring, and carefully timed delivery are additional important factors.

Chronic hypertension in pregnancy.

The course and outcome of 169 pregnancies in 156 women with chronic hypertension were studied. Antihypertensive medications were given if the diastolic blood pressure exceeded 90 mmHg. A number of major associated medical problems were found. Left ventricular hypertrophy, a serum creatinine greater than 1.0 mg%, and a diastolic pressure greater than 100 mmHg at less than 20 weeks' gestation were high-risk indicators. The overall perinatal mortality was 28.4 of 1000 (versus hospital of 25.6 of 1000). Despite antihypertensive therapy, one-third of the patients developed superimposed preeclampsia. The poorest outcome occurred in patients with superimposed preeclampsia necessitating delivery at 27 to 34 weeks' gestation (perinatal mortality = 238 of 1000). Antepartum fetal heart rate testing was abnormal in 10% of the patients with intrauterine growth retardation occurring in 15%. The incidence of fetal growth retardation was fourfold higher (20 versus 5%) in patients treated with antihypertensive drugs, particularly methyldopa as a single agent. However, this may have been related more to the study design than to a detrimental effect of the drug. The perinatal outcome in this study is similar to the outcome of studies in which antihypertensive therapy was withheld. This indicates that controlling the blood pressure is merely one aspect of the management of chronic hypertension in pregnancy. Accurate dating, attention to associated medical problems, antenatal fetal assessment by ultrasound and heart rate monitoring, and carefully timed delivery are additional important factors.

Chronic hypertension in pregnancy.

Chronic hypertension in pregnancy.

Chronic hypertension in pregnancy.

Chronic hypertension in pregnancy is associated with significant potential risks to both mother and baby. The risks can be reduced to, or even below those of the general population by appropriate and adequate therapy. This requires close supervision and maintenance of excellent blood pressure control and should involve in therapeutic decisions, not only the obstetrician, but also the physician and neonatologist. In our own experience this is best achieved by a specialised unit approach to the problem.

Drug therapy for mild chronic hypertension in pregnancy? : Arias F, Zamora J: Antihypertensive treatment and pregnancy outcome in patients with mild chronic hypertension. Obstet Gynecol 53:489, 1979

Drug therapy for mild chronic hypertension in pregnancy? : Arias F, Zamora J: Antihypertensive treatment and pregnancy outcome in patients with mild chronic hypertension. Obstet Gynecol 53:489, 1979

Plasma Volume Contraction: A Significant Factor in Both Pregnancy-Associated Hypertension (Pre Eclampsia) and Chronic Hypertension in Pregnancy

The role of plasma volume in hypertension in pregnancy (pre-eclampsia) was investigated. Significant volume expansion from non-pregnant levels (16.5 +/- 1.60 ml/cm height) was present throughout pregnancy in 189 normal women, reaching 23.1 +/- 1.21 ml/cm at 33-36 weeks amenorrhoea. In another 40 initially normotensive pregnant women who developed hypertension, similar early volume expansion was followed by significant volume contraction in the third trimester, before evaluation of blood pressure in 29 (20.6 +/- 1.26 ml/cm), after it in 11 (18.6 +/- 1.27 ml/cm). Equivalent volume contraction was present in another 44 women studied only after hypertension developed in the third trimester. Oedema had no value as a clinical sign. In another 30 women with chronic hypertension, blood pressure was inversely related to plasma volume (r = 0.822) and to fetal growth (r = -0.710), which was directly related to plasma volume (r = 0.701). Plasma volume depletion plays a significant role in hypertension in pregnancy.