C o m m e n t a r y

Commentary on the Management ofElevated Blood Pressure in Pregnancy

Marvin Moser, MD

The position paper on Hypertension in Preg-nancy from the American Society of Hyper-

tension (ASH), which was published in volume11, issue 4 of The Journal of Clinical Hyperten-sion represents the opinions of obstetrics, gyne-cology, and internal medicine experts. Currentguidelines for the management of hypertension inpregnancy are clearly outlined by the authorswho have had a long experience in managing thisdisease. Pathophysiologic changes that occur innormal pregnancy, hypertension in pregnancy,and toxemia of pregnancy are summarized.

It is difficult to critique a position paper that iswell written and carefully evaluates this seriousproblem, but some specific comments regardingtreatment are in order. These comments are basedon a 2-year experience in a toxemia clinic and 50+years of experience in treating elevated blood pres-sure (BP) in pregnant women. Since there are fewwell-controlled study data available regarding spe-cific therapy, the comments made represent sugges-tions to rethink the presently recommendedtreatment of pregnant women who have or developelevated BP.

It is well-known that BP decreases during thefirst trimester of pregnancy and that normal BPsduring this time may be as low as 100 ⁄70 mm Hg.BP tends to rise to levels of about 120 to 125 ⁄80 to

85 mm Hg in the second and third trimester. Thus,systolic BPs of 130–140 mm Hg or diastolic BPs>85 mm Hg represent abnormally elevated BPsduring this period. The ASH report notes that a sys-tolic BP of 140 mm Hg represents an abnormal BPin a pregnant woman. There is some evidence thatdiastolic BP >85 mm Hg at any stage of pregnancywill increase fetal mortality. Many guidelines andthe ASH paper do not, however, suggest treatmentuntil levels of about 160 ⁄105 mm Hg are recorded.There also does not appear to be a major distinc-tion made with regard to BP levels that require spe-cific therapy between women who are hypertensivebefore pregnancy and those who develop toxemiawith elevated BPs. Is this recommendation based ongood science or fear that giving medication mayresult in a poor outcome that, as the position paperstates, ‘‘may have to be defended before officialboards or committees’’?

The argument has been repeated that elevatedBPs of 140 to 150 ⁄90 to 95 mm Hg over a shortperiod probably do not result in any serious effectson the vascular system in pregnant women. There-fore, guidelines suggest that these levels of BP maynot require treatment. Abnormal clinical findingsmay not be detectable in patients with these levelsof BP. However, if careful vascular studies aredone, endothelial dysfunction, early left atrial andperhaps left ventricular changes, and vascularchanges in the kidney may be detected in peoplewhose BPs have been elevated for just a 3- to 4-month period. There is also some suggestive evi-dence that long-term cardiovascular events may bemore frequent in people who have untreatedelevated BP for short periods.

We suggest, based on the available data but withlittle solid long-term evidence (which, by the way,

From Yale University of Medicine, New Haven, CTAddress for correspondence:Marvin Moser, MD, 13 Murray Hill Road, Scarsdale,NY 10583E-mail: moserbp@aol.comManuscript received March 17, 2009;revised April 10, 2009; accepted April 10, 2009

doi: 10.1111/j.1751-7176.2009.00127.x

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may never be obtained) that lowering BPs that arehigher than 130 to 140 ⁄80 to 85 mm Hg shouldbe undertaken in pregnant women rather thanwaiting for higher levels, as suggested in the posi-tion paper. We are aware that lowering BP maynot prevent toxemia of pregnancy or preeclampsiabut we are also aware that this may prevent furtherelevations of BP and may delay the need for inter-vention. The position paper clearly states that ‘‘ges-tation is permitted to continue as long as BP iscontrolled’’ (and, of course, no overt signs of life-threatening maternal or fetal complications). If BPlevels are controlled before reaching the presentlyrecommended levels for treatment, it is possiblethat fewer instances of extremely high BP willoccur.

The National High Blood Pressure EducationProgram (NHBPEP) and American College ofObstetricians and Gynecologists guidelines ‘‘acceptwithholding antihypertensive drugs unless diastoliclevels are above 100 mm Hg (but supporttreatment at lower levels if there is evidence of end-organ damage or specific risk factors such as under-lying renal disease, which often is clinically difficultto detect). They note that ‘‘end points’’ for reinstat-ing treatment include exceeding a threshold BP of150 to 160 mm Hg systolic and 100 to 110 mmHg diastolic.

Obstetricians have a legitimate concern—medi-cations that might adversely affect the fetus shouldbe avoided. They continue to use alpha-methyl-dopa, hydralazine, and certain vasodilating b-block-ers, medications that they are comfortable with. Ofcourse, they have had more experience with theseagents—these are the medications they have beenrecommending for years. In the Fifth Report of theJoint National Committee on Prevention, Detec-tion, Evaluation, and Treatment of High BloodPressure (JNC), it was suggested that a hypertensivewoman who becomes pregnant should continuetaking her usual medication with the exception thatthe use of any renin-angiotensin aldosterone inhibi-tor (angiotensin-converting enzyme or angiotensinreceptor blocker) be stopped. These have been asso-ciated with fetal abnormalities. The JNC reportadvocated the continued use of calcium channelblockers, b-blockers, or diuretics if necessary tokeep BP below the goal of 140 ⁄90 mm Hg. Asnoted, it is recognized that during the first trimes-ter, BP may decrease and medication may have tobe decreased or temporarily discontinued. How-ever, when BP begins to rise, even to levels of 130to 140 ⁄80 to 85 mm Hg, it would appear logicalthat medications should again be increased or

restarted. At present, there is only limited evidencethat this approach will prevent the development ofhigher levels of BP later on in pregnancy, but thereis no firm evidence to suggest that lowering BPslowly will be detrimental to either the mother orthe fetus. Quite the opposite might be true. In onemeta-analysis of a large number of patients treatedwith a diuretic, for example, the occurrence of pre-eclampsia was reduced from 10.8% in a controlgroup to 7.7% in the treated group.

The ASH position paper advised that the risk ofcomplications ‘‘correlates with the age of thepatient, the duration and degree of control of herBP, and the presence of organ damage.’’ They notethat trials that have determined outcome in womenwith pre-pregnancy hypertension (chronic hyperten-sion) whose BP is treated during pregnancy may beflawed but do suggest fewer hospitalizations of themother, especially related to better BP control, withlittle definitive evidence of harm to the fetus. Thereis also little evidence, as noted, that this will pre-vent preeclampsia or toxemia. But treating elevatedBPs below levels now advocated in the ASH posi-tion paper appears to be logical and without harm.Keeping BPs at more normal levels should help toprevent the rare cases of cerebrovascular hemor-rhage or heart failure in pregnant women.

Our experience with the treatment of hyperten-sion in pregnancy cannot possibly match that ofthe authors of the position paper. Our experience,however, in treating hypertension before a crisisoccurs and maintaining BPs below 140 ⁄90 mm Hgthroughout pregnancy or of treating women whodevelop toxemia before BP levels rise to presentlyrecommended levels suggest that some cases of pro-gressive hypertension may be prevented. We areaware of initial studies suggesting that the use of b-blockers during pregnancy may result in smallerbirth weights. This, however, has not been con-firmed in other studies. We are also aware that pla-cental infarcts are often present in women who arehypertensive during pregnancy and that birthweights of babies born to women who are hyper-tensive are often lower than anticipated regardlessof therapy. These findings and not the effects ofspecific medications may account for smaller babiesin hypertensive women.

Some studies have suggested that a decrease inplacental blood flow occurs when diuretics areused. These studies, however, have been questionedespecially with regard to the methods used to deter-mine flow. There is little evidence that the use ofdiuretics in pregnancy is dangerous and some evi-dence, as noted, that the BP-lowering effects of

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these agents might be beneficial. Yet, obstetric ⁄gynecological textbooks suggest that the use ofdiuretics may be contraindicated. Since there is atendency during pregnancy for a volume increaseand sodium retention based on increased corticos-teroids, it would seem logical that some diureticuse would be necessary. In our limited experience,controlling BP in pregnancy without a diuretic isoften difficult.

Controversies remain as to whether and at whatlevel to treat rapidly rising BP near term or duringdelivery (a phenomenon often indicating theappearance of pure or superimposed preeclampsia).There is further debate on how aggressively tolower the BP. The NHBPEP recommendations statethat diastolic levels >105 mm Hg require treatment(although some contemporary texts still recommend>110 mm Hg), with some reservations. Circum-stances, such as a young women whose recent BPlevels were 110 to 120 ⁄70 to 80 mm Hg and haverisen rapidly or patients demonstrating signs of car-diac decompensation or cerebral symptoms such assevere headaches, confusion, or somnolence, war-rant treatment at lower levels. Perhaps keeping BPat lower levels throughout pregnancy might preventat least some cases of rapidly rising BPs during thelate third trimester.

The Table represents a simplified approach tomanaging elevated BP in pregnancy. Of course, ifBPs rise (1) despite adequate therapy, or (2) ifproteinuria increases or signs of platelet dysfunc-tion occur, then other measures (ie, bed rest,magnesium sulfate) and early intervention may benecessary.

Dividing patients into subgroups such as pre-eclampsia or toxemia superimposed on chronichypertension, for example, may not be necessarysince levels of BP will mainly determine specific

therapy. Obviously, other treatments outlined inthe position paper for preeclampsia or eclampsiashould be followed.

SUMMARYIt may give physicians some comfort in the man-agement of elevated BP in pregnancy to use drugssuch as alpha-methyldopa (the agent of choiceamong obstetricians), which may or may not beeffective in lowering BP adequately and oftenresults in annoying side effects, but this may not bethe best choice of therapy. Hydralazine, which hasalso been used for many years in the treatment ofhypertension in pregnancy, often loses its effective-ness over time and may cause tachycardias andheadaches; BP may not be lowered effectively.While this is presently recommended, it may alsonot be the drug of choice. Physicians are comfort-able with these medications because they have beenusing them for many years. This, however, shouldnot be the determining factor in choosing treat-ment. There are more effective and well-toleratedtherapies—diuretics, calcium channel blockers andb-blockers—that should be given before BPs rise tolevels currently recommended by some nationalguidelines. It is time to reexamine these recommen-dations. Angiotensin-converting enzyme inhibitorsor angiotensin receptor blockers should not begiven. Maintaining BP at more normal levels shouldprevent some episodes of maternal cerebral hemor-rhage and congestive heart failure. While these areuncommon, they most probably are dependent onthe actual levels of BP. Above all, it may be thatcontrolling BP even for just 4 to 6 months may pre-vent vascular damage in the future. At present thereis little evidence that careful lowering of BP withappropriate therapy will be detrimental to themother or the fetus.

Table. Suggested Simplified Approach to the Management of Hypertension in Pregnancya

Therapy Comments

Chronic hypertension (pre-pregnancy) Continue medication: diuretics, CCB,

or b-blocker (stop ACEI or ARB)

Dosage should be reduced during first

and mid-second trimester; if BP >140 ⁄ 90 mmHg, therapy should be increased or restarted

De novo elevation BP >20 weeks

(with or without proteinuria or edema)

Specific antihypertensive therapy,

CCBs, diuretics, b-blockers, ifBPs >140 ⁄ 90 mm Hgb

Possibility that preeclampsia or eclampsia

may not be prevented; reduction inmaternal complications

Abbreviations: ACEI, angiotensin-converting enzyme inhibitor; ARB, angiotensin receptor blocker; BP, blood pressure; CCB,calcium channel blocker. Other measures that are currently used in treating toxemia of pregnancy and the use of intravenous

therapy in eclampsia are clearly indicated. aThis approach has not been approved by any national or society guideline commit-tees. bAlpha-methyldopa and hydralazine may also be used.

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