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Query: UMLS:C0020538 (hypertension)
 170,190 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Definition and classification of the arterial hypertension in pregnancy are discussed. An emphasis is on the problems of differential diagnosis between pre-eclampsia and other forms of hypertension. Use of hypotensive drugs in pregnant patients with particular reference to emergencies is also discussed. The treatment of pregnant women with hypertension is still a problem which require close co-operation of both an obstetrician and internist. Follow-up after labour is GP duty to find out if the patient remains hypertensive. If so, etiology of the disease should be again searched.
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PMID:[Hypertension in pregnancy with special reference to its treatment]. 148 37

Erythrocyte sodium-lithium countertransport activity is increased in a subgroup of patients with essential hypertension but activity also rises temporarily during normal pregnancy. It is not known if the mechanism of raised activity is the same in both of these situations. Standard sodium-lithium countertransport activity and its kinetic characteristics (sodium affinity and maximum velocity) were measured in 15 women with a normal pregnancy. The mechanism of raised sodium-lithium countertransport activity was an increase in maximum velocity. There was no change in sodium affinity. This contrasts with essential hypertension where the mechanism is increased sodium affinity. Sodium-lithium countertransport activity was also measured in 14 primigravidae whose pregnancies were complicated by hypertension, and mean activity was not significantly higher than in normal pregnancy. However, six women had increased sodium affinity suggestive of essential hypertension and a different underlying mechanism of hypertension to those with normal sodium affinity. Prospective measurement of sodium-lithium countertransport kinetics may lead to a better understanding of the pathophysiology of hypertension in pregnancy.
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PMID:Sodium-lithium countertransport kinetics in normal and hypertensive human pregnancy. 155 43

64 pregnancies were analyzed in 41 women with biopsy-proven lupus nephritis between 1965-91; fetal and maternal outcome were evaluated and risk factors for poor outcome were identified. Of 65 fetuses, 22 (34%) were lost (including therapeutic abortions). 19 (30%) were liveborn but premature (or= 36 weeks gestation) and 24 (37%) were term. Fetal loss after 20 weeks gestation was 195. 12% of 25 fetuses whose birthweight was recorded were small for gestational age. Maternal renal function deteriorated in 19% of the pregnancies but was irreversible postpartum in only 1 woman (2%). Hypertension was recorded in 44% of pregnancies, developed early (or= 32 weeks gestation) in 28%, and was severe in 13%. Treated hypertension predated 17% of the pregnancies and in 6% (included in the overall incidence of hypertension) exacerbation occurred during pregnancy despite continued antihypertensive medication. 9 women (22%) who developed de novo hypertension in pregnancy had permanent hypertension postpartum. Increased proteinuria was recorded in 485 of pregnancies and was irreversible postpartum in 5%. The comparison of pregnancies occurring before or after diagnosis was made by renal biopsy and failed to show any significant difference in fetal outcome. Pregnancies which occurred after the diagnosis of glomerulonephritis were associated with a significantly lower incidence of maternal hypertension, early hypertension, severe hypertension, and increased proteinuria. The presence of circulating lupus anticoagulant was clearly associated with a significantly higher fetal loss rate although the incidence of maternal complications did not differ significantly between mothers positive or negative for lupus anticoagulant.
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PMID:Lupus nephritis and pregnancy. 163 Dec 63

The imbalance of cation transport is considered to play an important role in the development of hypertension, and this also applies to hypertension during pregnancy. Magnesium (Mg) is one of the factors that regulate cation transport across the cell membrane. We therefore studied the effect of a magnesium-deficient diet on the activity of erythrocyte Na/K-ATPase and Mg-ATPase from six pregnant rabbits and compared the results to those obtained from six controls on a normal diet. None of the rabbits on the deficient diet developed hypertension or intrauterine growth retardation; nevertheless the activity of both enzymes was significantly reduced compared to the group on the normal diet. Since the reduced activity of these enzymes can determine sodium or calcium retention in the cell, Mg deficiency could be the basis of the onset of some forms of hypertension in pregnancy.
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PMID:Effect of magnesium-deficient diet on cation transport in pregnant rabbits. 165 May 73

Nifedipine antagonises influx of calcium through cell membrane slow channels, and sustained release formulations of the calcium channel blocker have been shown to be effective in the treatment of mild to moderate hypertension and both stable and variant angina pectoris. Preliminary findings also indicate that these formulations are effective in the treatment of Raynaud's phenomenon and hypertension in pregnancy, and that they reduce the frequency of ischaemic episodes in some patients with silent myocardial ischaemia. The exact mechanism of action of nifedipine in all of these disorders has not been defined. However, its potent peripheral and coronary arterial dilator properties, together with improvements in oxygen supply/demand, are of particular importance. A major goal of sustained release therapy is to permit reductions in the frequency of nifedipine administration, preferably to once daily, and thus improve patient compliance. Two new once-daily formulations--the nifedipine gastrointestinal therapeutic system (GITS) and a fixed combination capsule comprising sustained release nifedipine 20 mg and atenolol 50 mg--have exhibited marked antihypertensive efficacy. The GITS preparation has also been used effectively in the treatment of stable angina pectoris, and both formulations appear to be well tolerated. Sustained release nifedipine formulations are generally better tolerated than their conventionally formulated counterparts, particularly with regard to reflex tachycardia. Adverse effects seem to be dose related, are mainly associated with the drug's potent vasodilatory action, and include headache, flushing and dizziness. Generally, these effects are mild to moderate in severity and transient, usually diminishing with continued treatment. Thus, sustained release nifedipine formulations are useful and established cardiovascular therapeutic agents which have demonstrable efficacy in various forms of angina, mild to moderate hypertension and Raynaud's phenomenon. Further, promising results shown by the nifedipine GITS formulation, with its advantage of once daily administration suggest that it is likely to become one of the preferred nifedipine formulations for the treatment of hypertension and the various forms of angina.
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PMID:Sustained release nifedipine formulations. An appraisal of their current uses and prospective roles in the treatment of hypertension, ischaemic heart disease and peripheral vascular disorders. 171 8

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.
Hypertension 1992 Feb
PMID:Renin-angiotensin-aldosterone system in normal and hypertensive pregnancy. Response to postural stimuli. 173 98

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 not 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. beta-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 antiplatelet therapy. This is consistent with the increasing evidence that preeclampsia is not primarily, or even necessarily, a hypertensive disease.
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PMID:Controlled trials of antihypertensive drugs in pregnancy. 182 49

This study has been performed to assess the effect of methyldopa (MD) therapy in pregnancy hypertension on the neonatal adaptation. Infants born to mothers on MD for several weeks prior to delivery and presenting with excessive tremor and irritability were evaluated according to the dose of maternal MD. Pregnancy hypertension and high dose MD was associated with impaired placental perfusion, compromised function of fetoplacental unit and more frequent surgical delivery. Infants of mothers on high (1.25-2.0 g/day) or low (less than 1 g/day) MD had gestational age, head circumference, acid-base balance, Apgar score and blood pressure similar to those born to healthy control mothers. The birth weight of infants of the high MD group, however, were significantly lower than in the low-dose or control groups. MD therapy resulted in a dose-dependent increase in plasma levels of prolactin, thyrotropin and triiodthyronine indicating decreased dopaminergic inhibition of pituitary hormone release. Plasma thyroxine concentration, however, decreased significantly. Cerebrospinal fluid noradrenaline was found to be markedly depressed after maternal MD showing disturbed central nervous system monoamine metabolism. It is suggested that MD administration to mothers presenting with pregnancy hypertension interferes with cerebral monoamine metabolism of the neonate and induces alterations in some endocrine functions under dopaminergic control. The possible role of chronic fetal distress frequently associated with pregnancy hypertension should also be considered.
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PMID:Neonatal effects of methyldopa therapy in pregnancy hypertension. 186 78

High blood pressure (BP) complicates approximately 10% of all pregnancies. Hypertension in pregnancy falls into four categories: (1) preeclampsia-eclampsia, (2) chronic hypertension of whatever cause, (3) preeclampsia-eclampsia superimposed to chronic hypertension or renal disease, and (4) transient or late hypertension (gestational hypertension). Preeclampsia, the association of hypertension, proteinuria, and edema, accounts for more than 50% of all the hypertensive disorders of pregnancy and is a major cause of fetal and maternal morbidity and mortality. Unfortunately, distinguishing between preeclampsia and other causes of hypertension on clinical grounds can be difficult because of the lack of specific tests for differential diagnosis. Increased vascular resistance has been claimed as the primary cause of preeclampsia; however, a variable hemodynamic profile with relatively high cardiac outputs, normal filling pressures, and inappropriately high systemic vascular resistances is now reported by most investigators. Imbalance between vasodilator and vasoconstrictor eicosanoids may account for platelet activation and increased responsiveness to pressor peptides. Altered prostacyclin (PGI2) to thromboxane A2 (TxA2) ratio in maternal uteroplacental vascular bed may favor local platelet activation and vasoconstriction contributing to placental insufficiency and fetal distress. Alternatively, recent evidence seems to suggest that fetal umbilical placental circulation may be the site of the primary vascular injury. Whether low-dose aspirin prevents preeclampsia because it inhibits the excessive maternal TxA2 or whether the partial inhibition of fetal TxA2 is also of therapeutic value remains to be established. Treatment of severe hypertension in pregnancy is probably important to prevent cardiac failure or cerebrovascular accidents in the mother. The need for pharmacological therapy of mild to moderate hypertension is still debated, since no formal studies are available to clarify whether pharmacological treatment in such instances effectively reduces maternal or fetal risk. For the treatment of preeclampsia, hydralazine and nifedipine may be used when delivery is not applicable. Labetalol and diazoxide are effective for hypertensive emergencies. Life-threatening hypertension that does not respond to more conventional therapy is an indication for the use of sodium nitroprusside. For chronic hypertension, alpha-methyldopa remains the treatment of choice; if ineffective, hydralazine or beta-blockers are suitable. Effectiveness and safety of other molecules remain elusive.
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PMID:Prevention and treatment of pregnancy-associated hypertension: what have we learned in the last 10 years? 188 20

Current methods for estimating gestational age using clinical parameters can be inaccurate in prematurity. A simplified ultrasonographic system, based on cerebral sulcal development, for clinically determining fetal maturation in newborns was developed and studied in 148 newborns (92 appropriate-for-gestational-age, 54 small-for-gestational-age and 2 large-for-gestational age). This ultrasonographic sulcal method correlates better with the gestational age by dates than by the Dubowitz scoring system in the neonates less than 30 weeks' gestation. There are significant correlations between gestational age assessed by dates and by sonographic sulcal age in both appropriate-for-gestational-age (R = 0.91, P less than 0.001) and small-for-gestational-age newborns (R = 0.92, P less than 0.001). Maternal hypertension during pregnancy is a significant risk factor associated with accelerated fetal cerebral maturation in 12 neonates. Although overestimate of gestational age may occur in neonates born to mothers with hypertension, cranial ultrasonography is an accurate and convenient method of estimating gestational age in neonates.
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PMID:Assessment of gestational age in newborns by neurosonography. 193 42


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