Pre‐Eclampsia: A Hypothesis for its PathogenesisEnhorning, Goran
doi: 10.3109/00016348409157115pmid: 6587731
Abstract. A hypothesis is presented according to which the pathogenesis of pregnancy‐induced hypertension can be attributed to disturbances in renal function caused by the upright posture of the human. In pregnancy, glomerular filtration rate (GFR) and tubular reabsorption, the latter stimulated by aldosterone, are working in high gear. A diminished GFR with continued stimulation of tubular re‐absorption would lead to sodium retention. That situation could result, particularly in the primigravida, from the enlarged uterus of late pregnancy exerting pressure on and interfering with venous return, arterial blood flow to kidneys, and/or ability of ureters to transport urine and maintain low pressure in the kidney pelvis. At an early stage, pre‐eclampsia can be controlled by bed rest, quite likely by removing dangerous uterine compression. Animal studies are required to test the hypothesis.
Sympatho‐Adrenal Activity in Different Hypertensive Disorders in Pregnancy: A short reviewNisell, H.; Lunell, N.‐O.
doi: 10.3109/00016348409157116pmid: 6587723
Abstract. The sympathetic nervous system is involved in blood pressure regulation in normal and hypertensive man via postganglionic nerve transmission mediated by norepinephrine, acting mainly on the α‐receptor to cause vaso‐constriction, and also via adrenomedullary secretion by epinephrine, acting mainly on the β‐receptors which will give rise to increased cardiac output and vasodilation in the muscular beds. Conflicting results regarding the role of the sympathoadrenal system in hypertension of pregnancy have been reported. This may be attributed partly to the varying methods that have been used to study this system. Specific measurement of the the activity of the sympathetic nerves is difficult, although direct recording of their activity has been performed (15). At present, plasma norepinephrine is considered to be an index of sympathoneural activity, reflecting the rate of release at the postganglionic nerve endings (5, 11) and plasma epinephrine is considered to be a marker of adrenal activity, since it is derived almost exclusively from the adrenal glands (5).
The Influence of Different Positions and Korotkoff Sounds on the Blood Pressure Measurements in PregnancyWichman, Klas; Rydén, Gunnar; Wichman, Mette
doi: 10.3109/00016348409157118pmid: 6587724
Abstract. The influence of the patient's posture on the measurement of arterial blood pressure has been studied during pregnancy. The blood pressure (BP) measured on the right arm in the left lateral recumbent position is significantly lower than in the supine, sitting, or erect positions. This difference is assumed to be due to hydrostatic factors. The diastolic BP should be read off at Korotkoff IV because the hyperkinetic circulation during pregnancy causes a pronounced variation in BP values when measurements are performed at Korotkoff sound V. The roll‐over test seems inappropriate as a screening test to predict pre‐eclampsia, because of the numerous false‐positive tests. The importance of measuring the BP under standardized conditions during pregnancy in order to detect minimal changes in BP as indicative of pathophysiology in pre‐eclampsia is emphasized.
The Incidence of Hypertensive Disease in PregnancyLindmark, Gunilla; Lindberg, Bo; Högstedt, Stellan
doi: 10.3109/00016348409157119pmid: 6587725
Abstract. Incidence figures for hypertensive disease in pregnancy (HDP) vary widely in epidemiological studies due to variations in definitions, the occurrence of risk factors and differing methods of data collection. In Uppsala county all pregnant women with a diastolic blood pressure of 90 mmHg or more were prospectively registered within a 2‐year‐period. The incidence of hypertension noted in the antenatal clinics was found to be 7.2%. In 56% of the cases hypertension was first noted after 37 weeks of gestation. The group of patients presenting before term with hypertension not normalized by bed rest in hospital and without complicating factors was only 14% of the whole material. The implications of the findings for discussions on therapy and complications in HDP are discussed.
Characteristics of Hypertension in PregnancyAndersch, Bjöm; Svensson, Anders; Hansson, Lennart
doi: 10.3109/00016348409157120pmid: 6587726
Abstract. During the period 1969‐73, 0.3% of 17000 unselected non‐diabetic pregnancies in our hospital were complicated by severe pre‐eclampsia, 0.6% by mild pre‐eclampsia and 0.6% by hypertension in pregnancy. Records from affiliated maternity centres and the hospital regarding these 261 women were studied and pertinent data assembled for comparison with 260 matched normotensive pregnancies. Instrumental deliveries were more common in all types of hypertensive pregnancy, with a 35% freqeuncy of caesarean section in severe pre‐eclampsia compared with fewer than 5% for controls. Significantly longer hospitalization and increased perinatal mortality were observed in hypertensive pregnancies, most pronounced in severe pre‐eclampsia. The combination of high blood pressure and proteinuria was associated with the greatest risk for premature birth, low infant weight and perinatal mortality. The overall incidence of hypertensive disorders in pregnancy was relatively low, 1.5%, but these women counted for a significant proportion of obstetric complications requiring hospitalization and instrumental delivery.
Methodological Problems in Studies on Hypertension Therapy During PregnancyHögstedt, Stellan; Lindmark, Gunilla; Lindberg, Bo
doi: 10.3109/00016348409157121pmid: 6587727
Abstract. As yet, no distinct aetiological factor underlying hypertension in pregnancy has been disclosed, and there is therefore no clearcut treatment for this condition. The lack of well‐defined end‐points makes it difficult to plan and evaluate the results of studies on the treatment of hypertension during pregnancy. However, we cannot await the solution to the puzzle of pre‐eclampsia before providing treatment for this hypertension. Well‐designed investigations to determine the most effective form of such treatment are therefore of great value and must be carried out in spite of the many problems associated with these studies. If given due consideration, as discussed in this paper, this problem can be alleviated.
Risk Grouping of 113 Patients with Hypertensive Disorders During Pregnancy, with Respect to Serum Urate, Proteinuria and Time of Onset of HypertensionLiedholm, H.; Montan, S.; Åberg, A.
doi: 10.3109/00016348409157122pmid: 6587728
Abstract. In order to describe the outcome of a one‐year material of hypertensive pregnancies, a retrospective analysis was made of the patients with respect to time of onset of hypertension, absence/presence of significant proteinuria, and maxium recorded serum urate values less or greater than 350 μmol/l. The material comprised 113 hypertensive patients, 3.7% of 3036 deliveries in 1980. Of these only 87 could be classified as intended. Twenty‐two patients lacked information on serum urate values, and the remaining 4 did not fulfil the inclusion criteria.
Drug Selection in the Treatment of Pregnancy Hypertension: A surveyLiedholm, H.; Melander, A.
doi: 10.3109/00016348409157123pmid: 6145284
Abstract. Effective blood pressure treatment has only been available during the last 20‐25 years. Most antihypertensive drugs employed for other hypertensive conditions have also been used in hypertensive states of pregnancy. In this survey, most of the drugs already in use and some new ones are discussed. No special emphasis is placed on the use of drugs in emergency situations. As β‐adrenoceptor blocking drugs are widely used nowadays, the principal differences between some β‐blockers are discussed in detail. A discussion of future requirements in order to get a better picture of the value of antihypertensive drugs completes this survey.