MATERNAL AND EARLY CHILD HEALTH

Health Evidence Bulletins - Wales

Date of Completion: 9.1.98

The contents of this bulletin are likely to be valid for approximately one year, by which time significantly new research evidence may become available


2. Hypertensive Disorders of Pregnancy

(Users are advised to consult the supporting evidence for a consideration of all the implications of a recommendation) 

A widely used classification of high blood pressure in pregnancy is that of the American College of Obstetricians and Gynaecologists (ACOG). The ACOG classification distinguishes between hypertension arising during the pregnancy (pregnancy induced hypertension, PIH) and pre-existing hypertension (chronic hypertension). The most important factor in management is the differentiation between hypertension alone and hypertension plus proteinuriai.
 
i. Hypertension in pregnancy. ACOG Technical Bulletin No. 219. Washington DC: ACOG, January 1996
2.1 MANAGEMENT OF HYPERTENSION IN PREGNANCY
The Statements The Evidence
2.1a Antihypertensive medication for moderate hypertension in pregnancy is effective in that it prevents a further increase in blood pressure but the effect on other important outcomes of pregnancy is unclear(i).
(Health gain notation - 2 "likely to be beneficial")
Methyldopa and Labetalol are the drugs most widely used. Neither is free from side effects(ii).
i. Chalmers I, Enkin M, Keirse MJNC. Effective care in pregnancy and childbirth. Oxford: Oxford University Press, 1989 pp. 513-514, 519-521
(Type I evidence - systematic review of limited evidence. Summary in Enkin M, Keirse MJNC, Renfrew M, Neilson J. A guide to effective care in pregnancy and childbirth. 2nd ed. Oxford: Oxford University Press. 1995. p. 93-95)
ii. Teoh TG, Redman CW. Management of pre-existing disorders in pregnancy: Hypertension. Prescribers’ Journal 1996; 36(1):28-36
(Type V evidence - expert opinion)
2.1b. Diuretics are unlikely to be helpful in the prevention or management of pre-eclampsia(i) .

(Health gain notation - 5 "unlikely to be beneficial")

i. Chalmers I, Enkin M, Keirse MJNC. Effective care in pregnancy and childbirth. Oxford: Oxford University Press, 1989 pp. 514-516
(Type I evidence - systematic review. Summary in Enkin M, Keirse MJNC, Renfrew M, Neilson J. A guide to effective care in pregnancy and childbirth. 2nd ed. Oxford: Oxford University Press. 1995. p. 91)
2.1c. The use of bed rest during pregnancy should be curtailed unless randomised controlled trials suggest any benefits(i).
(Health gain notation - 5 "unlikely to be beneficial")
i. Goldenberg RL, Cliver SP, Bronstein J, Cutter GR, Andrews WW, Mennemeyer ST. Bed rest in pregnancy. Obstetrics and Gynecology. 1994; 84: 131-6
(Type I evidence - systematic review using MEDLINE only)

Top

2.1d. Hospitalisation has not been shown to be superior to day care or home management for non-proteinuric hypertension(i).
A day-care unit for hypertension in pregnancy significantly reduced the need for, and the length of inpatient admissions (control patients spent a mean of 4 days longer in hospital than day-care patients) and the number of medical interventions, at the cost of an increase in outpatient attendances(ii).
(Health gain notation - 2 "likely to be beneficial")
i. Crowther CA, Bowmeester AM, Ashurst HM.
Does admission to hospital for bed rest prevent disease progression or improve fetal outcome in pregnancy complicated by non-proteinuric hypertension. British Journal of Obstetrics and Gynaecology. 1992; 99(1): 13-17
(Type II evidence - randomised controlled trial of 218 women between 28 and 38 weeks gestation);
ii. Tuffnell DJ, Lilford RJ, Buchan PC, Prendiville VM, Tuffnell AJ et al. Randomised controlled trial of day care for hypertension in pregnancy. Lancet. 1992; 339: 224-7
(Type II evidence - randomised controlled trial of 54 women)
2.1e. The measurement of the uric acid level is likely to be useful for reflecting fetal prognosis(i)

(Health gain notation - 2 "likely to be beneficial")

i. Chalmers I, Enkin M, Keirse MJNC. Effective care in pregnancy and childbirth. Oxford: Oxford University Press, 1989 p394
(Type IV evidence - observational studies. Summary in Enkin M, Keirse MJNC, Renfrew M, Neilson J. A guide to effective care in pregnancy and childbirth. 2nd ed. Oxford: Oxford University Press. 1995. pp. 55-56)
2.1f. Although a declining platelet count may be an early feature of pre-eclampsia, it has a limited diagnostic value because of the large variability in normal pregnancy. It is best considered as indicative of severe end stage disease(i).
(Health gain notation - 2 "likely to be beneficial")
i. Hayman RG, Baker PN. The hypertensive disorders of pregnancy. Definitions, classifications and haematological investigations. PACE review 97/05. London: Royal College of Obstetricians and Gynaecologists, 1997.
(Type IV evidence - observational studies)
Top
2.2 MANAGEMENT of FULMINATING PRE-ECLAMPSIA and ECLAMPSIA
The Statements The Evidence
For the treatment of these conditions, drug therapy (to reduce the maternal risk of encephalopathy and cerebral haemorrhage) is coupled with early delivery. The incidence of eclampsia in the United Kingdom is nearly 1 in 2000 maternities(i)i. i. Douglas KA, Redman CW. Eclampsia in the United Kingdom. British Medical Journal. 1994; 309:1395-1400
http://www.bmj.com/cgi/content/full/309/6966/1395
(Type IV evidence - a prospective descriptive study of 383 cases of eclampsia)
2.2a. The routine use of magnesium sulphate rather than diazepam or phenytoin is beneficial for the prevention of seizures of eclampsia(i,ii). In one trial, women allocated magnesium sulphate had a reduced risk of recurrent convulsions compared to diazepam (52% lower) and phenytoin (67% lower)(iii). (Some trials included cases of both severe pre-eclampsia and eclampsia).
(Health gain notation - 1 "beneficial")
caveat: The regimen recommended for intravenous administration of magnesium sulphate requires concomitant monitoring and special care, for which specific training is required.
i. Duley L, Henderson-Smart, D. Magnesium sulphate versus diazepam for eclampsia Cochrane Database of Systematic Reviews Cochrane Library , September 1996; Issue 3;
(Type I evidence - systematic review);
ii. Scientific Advisory Committee of the Royal College of Obstetricians and Gynaecologists. Management of Eclampsia. RCOG Guideline No. 10, London: Royal College of Obstetricians and Gynaecologists, November 1996
(Type II evidence - randomised controlled trial);
iii. Eclampsia Trial Collaborative Group. Which anticonvulsant for women with eclampsia? Evidence from the collaborative eclampsia trial. Lancet 1995; 345:1455-1463
(Type II evidence - randomised controlled trial)
2.2b. The use of magnesium sulphate in fulminating pre-eclampsia in the absnce of eclampsia has been reported in two small trials(i, ii).
(Health gain notation - 4 "unknown")
Further syudies are awaited to assess the value of magnesium sulphate in prophylaxis.
i. Friedman SA, Kee-Hak L, Baker CA, Repke JT. Phenytoin versus magnesium sulfate in pre-eclampsia: A pilt study. American Journal of Perinatology. 1993; 10(3): 233-238.
(Type II evidence - randomised controlled trial of 103 women);
ii. Appleton MP, Kuehl TJ, Raebel MA et al. Magnesium sulfate versus phenytoin for seizure prophylaxis in pregnancy-induced hypertension. American Journal of Obstetrics and Gynecology. 1991: 165(4): 907-913.
(Type II evidence - randomised controlled trial of 50 women)

Top

2.2c. The prescription of antihypertensive agents constitutes good practice for the treatment of severe pre-eclampsia(i)

(Health gain notation - 2 "likely to be beneficial").

caveat: Hydralazine or labetalol are the most commonly used hypotensives. There is insufficient evidence to recommend one in preference to the other(ii).

i. Chalmers I, Enkin M, Keirse MJNC. Effective care in pregnancy and childbirth. Oxford: Oxford University Press, 1989 pp. 519-526
(Type I evidence - systematic review of limited evidence. Summary in Enkin M, Keirse MJNC, Renfrew M, Neilson J. A guide to effective care in pregnancy and childbirth. 2nd ed. Oxford: Oxford University Press. 1995. p. 95)
ii. Scientific Advisory Committee of the Royal College of Obstetricians and Gynaecologists. Management of Eclampsia. RCOG Guideline No. 10, London: Royal College of Obstetricians and Gynaecologists, November 1996
(Type V evidence - expert opinion)
2.2d. One small trial suggested that expectant rather than aggressive management of patients with severe pre-eclampsia at 28 to 32 weeks gestation, with close monitoring of mother and fetus at a ‘perinatal centre’, reduced neonatal complications and stay in the neonatal intensive care unit (From 95 eligible patients, admissions to neonatal intensive care were 76% vs 100%. Mean days stay were 20.2 vs 36.6)(i). Timing of delivery should be judged by the health of the mother and the facilities available for the care of the very preterm infant(ii).
(Health gain notation - 3 "trade-off between beneficial and adverse effects")
i. Sibai BM, Mercer BM, Eyal Schiff MD, Friedman MD. Aggressive versus expectant management of severe preeclampsia at 28 to 32 weeks’ gestation: A randomized controlled trial
American Journal of Obstetrics and Gynecology 1994; 171(3):818-822
(Type II evidence - randomised controlled trial of 95 women);
ii. Internal Review Group (See Contributors)
(Type V evidence - expert opinion)
2.2e. There is insufficient evidence for the use of plasma volume expansion in the management of severe pre-eclampsia where the theoretical need to treat a reduced plasma volume carries a serious risk of volume overload and pulmonary and cerebral oedema in women with a low colloid osmotic pressure(i)i.
(Health gain notation - 4 "unknown")
i. Enkin M, Keirse MJNC, Renfrew M, Neilson J. A guide to effective care in pregnancy and childbirth. 2nd ed. Oxford: Oxford University Press, 1995. pp. 96
(Type IV evidence - uncontrolled studies. Further controlled trials are needed)
Top
2.3 SCREENING and PROPHYLAXIS against PRE-ECLAMPSIA
The Statements The Evidence
2.3a. Regular monitoring of blood pressure and testing for proteinuria during pregnancy is accepted good practice(i)

(Health gain notation - 2 "likely to be beneficial")

i. Chalmers I, Enkin M, Keirse MJNC. Effective care in pregnancy and childbirth. Oxford: Oxford University Press, 1989 pp. 383-385
(Type IV evidence - observational studies. Summary in Enkin M, Keirse MJNC, Renfrew M, Neilson J. A guide to effective care in pregnancy and childbirth. 2nd ed. Oxford: Oxford University Press. 1995. pp. 52-54)
2.3b. The prophylactic administration of low dose aspirin to any category of women at high risk of developing pregnancy induced hypertension (PIH) is unlikely to be effective(i,ii)i.

(Health gain notation - 5 "unlikely to be beneficial")

i. ECPPA group. ECPPA randomised trial of low-dose aspirin for the prevention of maternal and fetal complications in high-risk pregnant women. British Journal of Obstetrics and Gynaecology 1996; 103:39-47
(Type II evidence - randomised controlled trial of 1009 women)
ii. de Swiet, M. The use of low-dose aspirin in pregnancy. PACE assessment review 96/03. London: Royal College of Obstetricians and Gynaecologists, 1996.
(Type I evidence - systematic review)
2.3c. The screening for pre-eclampsia by uric acid measurement, oedema, cold pressor test, roll-over test or isometric exercise test is unlikely to be beneficial (i).

(Health gain notation - 5 "unlikely to be beneficial")

i. Chalmers I, Enkin M, Keirse MJNC. Effective care in pregnancy and childbirth. Oxford: Oxford University Press, 1989 pp. 385, 391-394
(Type IV evidence - observational studies. Summary in Enkin M, Keirse MJNC, Renfrew M, Neilson J. A guide to effective care in pregnancy and childbirth. 2nd ed. Oxford: Oxford University Press. 1995. pp. 55-56)
2.3d. The effect of a change in salt intake in the development of pregnancy-induced hypertension is unknown(i).

(Health gain notation - 4 "unknown")

i. Chalmers I, Enkin M, Keirse MJNC. Effective care in pregnancy and childbirth. Oxford: Oxford University Press, 1989 pp. 294-295
(Type IV evidence - observational studies. Summary in Enkin M, Keirse MJNC, Renfrew M, Neilson J. A guide to effective care in pregnancy and childbirth. 2nd ed. Oxford: Oxford University Press. 1995. p. 92)
2.3e. Preliminary trials suggest that calcium supplementation results in a significant reduction in blood pressure in pregnant women (OR for preeclampsia = 0.38)(i).
(Health gain notation - 2 "likely to be beneficial")
caveat: Insufficient evidence exists of any reduction in subsequent morbidity and the results of further large trials are awaited.
i. Bucher, HC, Guyatt GH, Cook RJ, et al. Effect of calcium supplementation on pregnancy-induced hypertension and pre-eclampsia .Journal of the American Medical Association 1996; 275 (14): 1113-7 (Type I evidence - meta analysis of 2459 women. Further large trials are in progress)
Top

Contents Home

Health Evidence Bulletins: Wales, Duthie Library, UWCM, Cardiff CF14 4XN. e-mail: weightmanal@cardiff.ac.uk