Jump to: Page Content, Site Navigation, Site Search,
You are seeing this message because your web browser does not support basic web standards. Find out more about why this message is appearing and what you can do to make your experience on this site better.
L A Magee Departments of Medicine, and Obstetrics and
Gynaecology, University of Toronto, Toronto, Canada
Correspondence to: Dr L A Magee, Department
of Medicine, Mount Sinai Hospital, Toronto, Ontario, Canada M5G 1X5
laura.magee{at}utoronto.ca
Hypertension in pregnancy is not a single
entity1 but comprises:
Summary points
Antihypertensive treatment is well tolerated in pregnancy, with
few women needing to change drugs due to side effects
Antihypertensive treatment for mild chronic hypertension benefits the
mother, but the impact on perinatal outcomes is less clear,
particularly for atenolol
For hypertension presenting later in pregnancy, even near term, the
available data do not allow for reliable conclusions to be made about
the benefits and risks of restricted activity with or without admission
to hospital
Antihypertensive treatment for mild to moderate hypertension later in
pregnancy benefits the mother, but the impact on perinatal outcomes may
be harmful or beneficial
Women with early, severe pre-eclampsia have better perinatal outcomes
if they are managed "expectantly," but data are insufficient to
estimate risks to the mother
For acute severe hypertension later in pregnancy, parenteral
hydralazine is not the drug of choice as it is associated with more
maternal and perinatal adverse effects than are other drugs,
particularly intravenous labetalol or oral or sublingual nifedipine
Antihypertensive treatment given antenatally should probably be
reordered postnatally
The types of hypertension in pregnancy differ primarily in the incidence, and not the nature, of maternal and perinatal complications. The UK confidential inquiries into maternal deaths has consistently shown an excess maternal mortality associated with hypertension in pregnancy due to intracerebral haemorrhage, eclampsia, or end organ dysfunction. Perinatal mortality and morbidity reflect both the fetal syndrome of pre-eclampsia (intrauterine growth restriction) and the consequences of iatrogenic prematurity resulting from deteriorating maternal disease or fetal condition.
Treatment aims to improve both maternal and perinatal outcomes. In this
article we review randomised controlled trials of drug and non-drug
treatments for hypertension in pregnancy.
| |
Methods |
|---|
|
|
|---|
We searched Medline (1966-97), Hypertension in Pregnancy (to 1997), bibliographies, and texts for articles in English or French that met several criteria (box). Data were abstracted independently by two reviewers who corroborated their findings. The most recent data were abstracted from duplicate publications.
|
Criteria for selection of articles
|
Quantitative analysis was performed with the Cochrane Review Manager software (version 3.0.1) that uses the Peto odds ratio (95% confidence interval) as the summary statistic. Where it occurs, we describe differences in outcomes between trials that were greater than could be expected by chance alone. We qualitatively analysed the study design, participants, interventions, and outcome definitions.
For hypertension presenting later in pregnancy, most trials did
not distinguish between pre-eclampsia, gestational, or chronic causes;
therefore we classified participants as having hypertension that was
either chronic or that developed later in pregnancy. Severity of
hypertension was defined as mild (90-99 mm Hg), moderate (100-109 mm Hg), or severe (
110 mm Hg) on the basis of diastolic blood
pressure at enrolment. Most trials did not report how blood pressure
was measured or whether Korotkoff phase IV or V was used.
| |
Chronic hypertension |
|---|
|
|
|---|
Seven trials enrolled 623 participants with mild chronic hypertension and compared antihypertensive treatment with no treatment. 2 3 Treatment aimed for a diastolic blood pressure less than 90 mm Hg.
|
Figure 1 shows that antihypertensives were more effective than no
therapy in decreasing the incidence of severe hypertension (blood
pressure greater than 160/100 mm Hg) and the requirement for additional
antihypertensives. Methyldopa (500-3000 mg/day in 2-4 doses) and
labetalol (200-1200 mg/day in 2-4 doses) have been used most
commonly, although all antihypertensives seem to be equally effective.
Decrease in admission to hospital before delivery was shown in only one
trial,4 conducted in 1978 before the advent of obstetric
day units. Although the decrease in proteinuria at delivery (a marker
for pre-eclampsia) reaches borderline significance, definitions of
proteinuria varied widely and trials were inconsistent, with the
largest effect shown in the trial of ketanserin (a selective serotonin
(5-HT2) receptor blocker with activity as an
1 blocker and inhibitor of platelet
aggregation in vitro). Drugs were well tolerated, with only 3.1%
(3/98) of women changing them because of side effects. No reliable
conclusions can be drawn about other maternal outcomes.
Figure 1 also shows no effect of treatment on perinatal outcomes, but confidence intervals are wide, and are consistent with both benefit and risk. Trials were inconsistent in finding an impact of treatment on the incidence of small for gestational age infants; specifically, a small trial of atenolol versus placebo5 reported a dramatic increase in small for gestational age infants among the atenolol treated group (odds ratio 17.3, 95% confidence interval 3.8 to 77.9), a result that remains unexplained despite the trial's methodological problems.
Antihypertensive treatment for mild chronic hypertension benefits the
mother. The impact on perinatal outcomes is less clear. If treatment is
given then drugs other than atenolol may be preferable until
further data are available.
| |
Hypertension in later pregnancy |
|---|
|
|
|---|
Non-drug approaches
Treatment guidelines have recommended use of
non-pharmacological approaches for hypertension in later pregnancy, with or without antihypertensives, particularly for mildly increased blood pressure.6 Six trials enrolled 607 participants and
compared ambulation out of hospital with bed rest in
hospital
7 8
or ambulation with bed rest among women
admitted to hospital with mild hypertension later in
pregnancy.
9 10
No trials have enrolled women with
moderate to severe hypertension. Figure 2 shows that there was no
effect of restricted activity (with or without admission to hospital)
on maternal or perinatal outcomes, although women managed as
outpatients spent an average of 2.3 weeks (95% confidence interval 1.9 to 2.8) less in hospital.
|
|
|
Antihypertensive drug treatment
Fifteen trials enrolled 1926 participants and compared
antihypertensives with no treatment for mild to moderate hypertension
later in pregnancy.
1 13-16
The drugs used most commonly were methyldopa (two trials) and
blockers (eight),
particularly labetalol (5/8). Treatment aimed for a diastolic blood
pressure less than 90 mm Hg.
blockers
(bradycardia was detected only by close monitoring of neonatal heart
rate and did not require intervention); and (c) there was a
trend towards an increase in the incidence of small for gestational age
infants. Although no adverse effects on neurodevelopment were shown,
few children exposed in utero to either methyldopa17 (98 infants) or atenolol18-55 have been studied.
Clearly, antihypertensive treatment benefits the mother with mild to
moderate hypertension later in pregnancy. No reliable conclusions,
however, can be drawn about the overall impact of treatment on
perinatal outcomes. The decrease in respiratory distress syndrome may
be due to reporting bias. The increase in small for gestational age
infants does not reach statistical significance.
If antihypertensive treatment is chosen, there is no clear choice of
drugs. Figure 4 shows that the 23 trials19-29 (1349 participants) comparing one agent with another (usually methyldopa, 15 trials) showed no differences in maternal or perinatal outcomes;
however, confidence intervals were wide, and clinically important
effects have not been ruled out. By subgroup analysis,
blockers may be less effective antihypertensives than calcium channel blockers
that is, slow release verapamil or nicardipine (odds ratio for severe hypertension in three trials 2.52, 95% confidence interval 1.29 to
1.52), however, this result must be interpreted cautiously as it rests
on two trials with inadequate methods of
randomisation.26
| |
Severe hypertension presenting later in pregnancy |
|---|
|
|
|---|
Aggressive versus expectant management
Mortality and morbidity related to prematurity remain significant
problems if women with acute, severe hypertension (usually of
pre-eclampsia) present before 34 weeks of gestation and are stabilised
and delivered. Therefore, a more "expectant" approach has been
advocated and tested in two trials
30 31
of 133 women. The
average pregnancy prolongation was 2.0 weeks (95% confidence interval
1.4 to 2.6). Figure 5 shows that "aggressive" management compared
with "expectant" management results in equivalent maternal
morbidity, fewer small for gestational age infants, and more markers of
serious neonatal morbidity. The trials, however, had low statistical
power to rule out excess maternal morbidity (for example, HELLP
(haemolysis, elevated liver enzymes, and low platelets)
syndrome32) or mortality. The requisite close maternal and
fetal surveillance may not be possible in all
settings.
|
Parenteral antihypertensive therapy
The 11 relevant trials with 570 participants
1 33-35
do not support recommendations
favouring hydralazine.36 These trials compared intravenous
hydralazine (5-10 mg bolus; infusion 3-10 mg/hour (maximum 15-80 mg/hour); or 20-40 mg intramuscularly) with other antihypertensives,
most commonly intravenous labetalol (four trials; 10-20 mg boluses over
2 minutes, every 10 minutes as needed) or oral or sublingual nifedipine
(four trials; 5-10 mg orally, every 30 minutes as needed). Figure 6
shows that, compared with intravenous hydralazine, other agents were
associated with less maternal hypotension, fewer caesarean sections,
fewer placental abruptions, and fewer low Apgar scores; neonatal
bradycardia was increased with labetalol, but only one of six affected
neonates required treatment.
|
Other approaches
The enthusiasm for plasma volume expansion comes from the
observation that women with severe pre-eclampsia have reduced cardiac
index and increased systematic vascular resistance, and that some of
them respond to comparatively small doses of antihypertensives, with
precipitous falls in blood pressure. Two small trials enrolled 42 participants in their third trimester, and described no serious
maternal complications of plasma volume expansion when both a Swan-Ganz
catheter and an arterial line were placed. The trials were not,
however, large enough to rule out clinically important increases or
decreases in maternal morbidity, and the treatment duration was
insufficient to comment on perinatal outcomes. The safety and
usefulness of plasma volume expansion must be further defined before it
can be advocated for use outside the setting of a research project,
unless women have a prolonged decrease in urine output or severe
hypertension that responds to antihypertensives with hypotension.
Anaesthesia
The observed decline in maternal mortality has been credited, in
part, to expanded anaesthetic resources devoted to
obstetrics.41 Both regional and general anaesthesia are
associated with risks: regional anaesthesia with fluid overload and
hypotension, and general anaesthesia with aspiration of gastric contents. One trial randomised 80 women with severe pre-eclampsia to
spinal-epidural, epidural, or general anaesthesia for caesarean section.42 General anaesthesia was associated with less
maternal hypotension and crystalloid infused, but spinal-epidural
anaesthesia (but not epidural) was associated with less frequent
admission to a special care baby unit. The data are insufficient to
allow reliable conclusions to be drawn about preference in women
eligible for either route of anaesthesia. Clearly, some women are not
candidates for regional anaesthesia because of falling platelet counts
or a poor fetal cardiotocograph necessitating immediate delivery. One
trial of 25 women with pre-eclampsia undergoing general anaesthesia found that intravenous labetalol given prophylactically attenuated the
hypertensive (and tachycardic) response to intubation.43
| |
Postpartum hypertension |
|---|
|
|
|---|
Only three trials addressed the management of hypertension during the first 48 hours post partum. Women who took magnesium sulphate had an equivalent control of severe hypertension when they received oral nifedipine or placebo (30 women),44 and slightly better control of mild to moderate hypertension when given hydralazine intramuscularly compared with being given methyldopa intravenously (26 women).45 No trial data addressed whether or not antihypertensives should be restarted after delivery in women not taking magnesium sulphate, in whom methyldopa and timolol were equally effective antihypertensives (80 women).46
As blood pressure rises progressively over the first five
postnatal days47 and commonly used antihypertensives are
safe for breast feeding,48 pending future studies it
would seem advisable to continue antihypertensive treatment after
delivery, at least in women not taking magnesium sulphate.
Traditionally, methyldopa has been avoided owing to depression and
fatigue observed with long term treatment of non-pregnant patients, but
such side effects may not be relevant over a shorter treatment
interval. Although agents with short half lives (for example,
labetalol) reach steady state drug levels more quickly than agents with
longer half lives, clinicians are advised to use the agent with which
they are most familiar. Women with pregnancy induced hypertension
usually need antihypertensives for days to weeks.49
| |
Footnotes |
|---|
Competing interests: None declared.
| |
References |
|---|
|
|
|---|
| 1. | National High Blood Pressure Education Program Working Group report on high blood pressure in pregnancy. Am J Obstet Gynecol 1990; 163: 1691-1712[Medline]. |
| 2. |
Sibai BM.
Treatment of hypertension in pregnant women.
N Engl J Med
1996;
335:
257-265 |
| 3. | Steyn DW, Odendaal HJ. Randomised controlled trial of ketanserin and aspirin in prevention of pre-eclampsia. Lancet 1997; 350: 1267-1271[Medline]. |
| 4. | Arias F, Zamora J. Antihypertensive treatment and pregnancy outcome in patients with mild chronic hypertension. Obstet Gynecol 1978; 53: 489-494. |
| 5. | Butters L, Kennedy S, Rubin PC. Atenolol in essential hypertension during pregnancy. BMJ 1990; 301: 587-589. |
| 6. | Rey E, LeLorier J, Burgess E, Lange IR, Leduc L. Report of the Canadian Hypertension Society consensus conference. 3. Pharmacologic treatment of hypertensive disorders in pregnancy. Can Med Assoc J 1997; 157: 1245-1254[Abstract]. |
| 7. | Duley L. Hospitalisation for non-proteinuric pregnancy hypertension. In: Pregnancy and childbirth module. Cochrane Collaboration. Cochrane Library, Issue 1. Oxford: Update Software , 1993. |
| 8. | Tuffnell DJ, Lilford RJ, Buchan PC, Prendiville VM, Tuffnell AJ, Holgate MP, et al. Randomised controlled trial of day care for hypertension in pregnancy. Lancet 1992; 339: 224-227[Medline]. |
| 9. | Crowther CA. Strict bed rest vs ambulation in the management of patients with proteinuric hypertension in pregnancy. In: Pregnancy and childbirth module. Cochrane Collaboration. Cochrane Library, Issue 1. Oxford: Update Software , 1993. |
| 10. | Matthews DD, Agarwal V, Shuttleworth TP. A randomized controlled trial of complete bed rest versus ambulation in the management of proteinuric hypertension during pregnancy. Br J Obstet Gynaecol 1982; 89: 128-131[Medline]. |
| 11. | Rothberg AD, Shuenyane E, Sefuba M. Psychosocial support for mothers with pregnancy-related hypertension: effect on birthweight. Pediatr Rev Commun 1991; 6: 13-20. |
| 12. | Somers PH, Gevirtz RN, Jasin SE. The efficacy of biobehavioral and compliance interventions in the adjunctive treatment of mild pregnancy-induced hypertension. Biofeedback Self-Regul 1989; 14: 309-318[Medline]. |
| 13. | Menzies DN. Controlled trial of chlorothiazide in treatment of early pre-eclampsia. BMJ 1964; 1: 739-742[Medline]. |
| 14. | Walker JJ, Crooks A, Erwin L, Calder AA. Labetalol in pregnancy-induced hypertension: fetal and maternal effects. In: Reily A, Symonds EM, eds. International Congress Series 591. Excerpta Med 1982;148-60. |
| 15. |
Bott-Kanner G, Hirsch M, Friedman S, Boner G, Ovadia J, Merlob P, et al.
Antihypertensive therapy in the management of hypertension in pregnancy a clinical double-blind study of pindolol.
Clin Exp Hypertension Pregnancy
1992;
B11:
207-220.
|
| 16. | Wide-Swensson DH, Ingemarsson I, Lunell NO, Forman A, Skajaa K, Lindberg B, et al. Calcium channel blockade (isradipine) in treatment of hypertension in pregnancy: a randomized placebo-controlled study. Am J Obstet Gynecol 1995; 173: 872-878[Medline]. |
| 17. | Cockburn J, Ounsted M, Moar VA, Redman CWG. Final report of study on hypertension during pregnancy: the effects of specific treatment on the growth and development of the children. Lancet 1982;647-9. |
| 18. | Reynolds B, Butters L, Evans J, Adams T, Rubin PC. First year of life after the use of atenolol in pregnancy associated hypertension. Arch Dis Child 1984; 59: 1061-1063[Abstract]. |
| 19. | Collins R, Duley L. Any antihypertensive therapy for pregnancy hypertension. In: Pregnancy and childbirth module. Cochrane Collaboration. Cochrane Library, Issue 1. Oxford: Update Softrware , 1994. |
| 20. | Lardoux H, Blazquez G, Leperlier E, Gerard J. Essai ouvert, comparatif, avec tirage au sort pour le traitment de l'HTA gravidique moderee: methyldopa, acebutolol, labetalol. Arch Mal Coeur 1988; 81: 137-140[Medline](suppl HTA). |
| 21. | El-Qarmalawi AM, Morsy AH, Al-Fadly A, Obeid A, Hashem M. Labetalol vs methyldopa in the treatment of pregnancy-induced hypertension. Int J Gynaecol Obstet 1995; 49: 125-130[Medline]. |
| 22. | Oumachigui A, Verghese M, Balachander J. A comparative evaluation of metoprolol and methyldopa in the management of pregnancy-induced hypertension. Indian Heart J 1992; 44: 39-41[Medline]. |
| 23. |
Hjertberg R, Faxelius G, Lagercrantz H.
Neonatal adaptation in hypertensive pregnancy a study of labetalol vs hydralazine treatment.
J Perinat Med
1993;
21:
69-75[Medline].
|
| 24. | Paran E, Holzberg G, Mazor M, Zmora E, Insler V. Beta-adrenergic blocking agents in the treatment of pregnancy-induced hypertension. Int J Clin Pharmacol Ther 1995; 33: 119-123[Medline]. |
| 25. |
Montan S, Anandakumar C, Arulkumaran S, Ingemarsson I, Ratnam SS.
Randomised controlled trial of methyldopa and isradipine in preeclampsia effects on uteroplacental and fetal hemodynamics.
J Perinat Med
1996;
24:
177-184[Medline].
|
| 26. | Marlettini MG, Crippa S, Morselli-Labate AM, Contarini A, Orlandi C. Randomised comparison of calcium antagonists and beta-blockers in the treatment of pregnancy-induced hypertension. Curr Ther Res 1990; 45: 684-694. |
| 27. | Wide-Swensson D, Montan S, Arulkumaran S, Ingemarsson I, Ratnam SS. Effect of methyldopa and isradipine on fetal heart rate pattern assessed by computerized cardiotocography in human pregnancy. Am J Obstet Gynecol 1993; 169: 1581-1585[Medline]. |
| 28. |
Voto LS, Zin C, Neira J, Lapidus AM, Margulies M.
Ketanserin versus -methyldopa in the treatment of hypertension during pregnancy: a preliminary report.
J Cardiovasc Pharmacol
1987;
10(suppl 3):
101-13S.
|
| 29. |
Horvath JS, Phippard A, Korda A, Henderson-Smart DJ, Child A, Tiller DJ.
Clonidine hydrochloride a safe and effective antihypertensive agent in pregnancy.
Obstet Gynecol
1985;
66:
634-638 |
| 30. | Sibai BM, Mercer BM, Schiff E, Friedman SA. Aggressive versus expectant management of severe preeclampsia at 28 to 32 weeks' gestation: a randomized controlled trial. Am J Obstet Gynecol 1994; 171: 818-822[Medline]. |
| 31. |
Odendaal HJ, Pattinson RC, Bam R, Grove D, Kotze TJvW.
Aggressive or expectant management for patients with severe preeclampsia between 28-34 weeks' gestation: a randomized controlled trial.
Obstet Gynecol
1990;
76:
1070-1075 |
| 32. | Olah KS, Redman CWG, Gee H. Management of severe, early pre-eclampsia: is conservative management justified? Eur J Obstet Gynecol Reprod Biol 1993; 51: 175-180[Medline]. |
| 33. | Griffis KR, Martin JN, Palmer SM, Martin RW, Morrison JC. Utilization of hydralazine or alpha-methyldopa for the management of early puerperal hypertension. Am J Perinatol 1989; 6: 437-441[Medline]. |
| 34. | Bhorat IE, Naidoo DP, Rout CC, Moodley J. Malignant ventricular arrhythmias in eclampsia: a comparison of labetalol with dihydralazine. Am J Obstet Gynecol 1993; 168: 1292-1296[Medline]. |
| 35. | Jegasothy R, Paranthaman S. Sublingual nifedipine compared with intravenous hydralazine in the acute treatment of severe hypertension in pregnancy: potential for use in rural practice. J Obstet Gynaecol Res 1996; 22: 21-24[Medline]. |
| 36. | Howarth GR, Seris A, Venter C, Pattinson RC. A randomized controlled pilot study comparing urapidil to dihydralazine in the management of severe hypertension in pregnancy. Hypertension Pregnancy 1997; 16: 213-221. |
| 37. | Ales K. Magnesium plus nifedipine. Am J Obstet Gynecol 1990; 162: 288[Medline]. |
| 38. | Brown MA, McCowan LME, North RA, Walters BN. Withdrawal of nifedipine capsules: jeopardising the treatment of acute severe hypertension in pregnancy? Med J Aust 1997; 166: 640-643[Medline]. |
| 39. | Gülmezoglu AM, Hofmeyr GJ, Oosthuisen MMJ. Antioxidants in the treatment of severe pre-eclampsia: an explanatory randomised controlled trial. Br J Obstet Gynaecol 1997; 104: 689-696[Medline]. |
| 40. | Moodley J, Gouws E. A comparative study of the use of epoprostenol and dihydralazine in severe hypertension in pregnancy. Br J Obstet Gynaecol 1992; 99: 727-730[Medline]. |
| 41. | Department of Health. Confidential enquiries into maternal death in the United Kingdom 1985-87. London: HMSO , 1991. |
| 42. | Wallace CH, Leveno KJ, Cunningham FG, Giesecke AH, Shearer VE, Sidawi JE. Randomized comparison of general and regional anesthesia for cesarean delivery in pregnancies complicated by severe preeclampsia. Obstet Gynecol 1996; 86: 193-199. |
| 43. | Ramanathan J, Sibai BM, Mabie W, Chauhan D, Guiz AG. The use of labetalol for attenuation of the hypertensive response to endotracheal intubation in preeclampsia. Am J Obstet Gynecol 1988; 159: 650-654[Medline]. |
| 44. | Barton JR, Hiett AK, Conover WB. The use of nifedipine during the postpartum period in patients with severe preeclampsia. Am J Obstet Gynecol 1990; 162: 788-792[Medline]. |
| 45. | Griffis KR, Martin JN, Palmer SM, Martin RW, Morrison JC. Utilization of hydralazine or alpha-methyldopa for the management of early puerperal hypertension. Am J Perinatol 1989; 6: 437-441. |
| 46. | Fidler J, Smith V, de Swiet M. A randomized study comparing timolol and methyldopa in hospital treatment of puerperal hypertension. Br J Obstet Gynaecol 1982; 89: 1031-1034[Medline]. |
| 47. | Walters BNJ, Thompson ME, Lee A, de Swiet M. Blood pressure in the puerperium. Clin Sci 1986; 71: 589-594[Medline]. |
| 48. | Briggs GG, Freeman RK, Yaffe SJ. Drugs in pregnancy and lactation, 4th ed. In: Baltimore: Williams and Wilkins , 1994. |
| 49. | Giannina G, Belfort MA. Use of transcranial and orbital Doppler sonography in normal pregnancy and pre-eclampsia: a review. J Soc Obstet Gynaecol 1997; 19: 1249-1263. |
(Accepted 12 March 1999)
Read all Rapid Responses
UK medical students have published unreleased government plans to restrict failed asylum seekers' access to medical care