Clinical Review

Pregnancy-Induced Hypertension

Clinician Reviews. 2012 May;22(5):27-32

References

1. Report of the National High Blood Pressure Education Program Working Group on high blood pressure in pregnancy. Am J Obstet Gynecol. 2000;183(1):S1-S22.

2. Sibai BM. Diagnosis and management of gestational hypertension and preeclampsia. Obstet Gynecol. 2003;102(1):181-192.

3. Kuklina EV, Ayala C, Callaghan WM. Hypertensive disorders and severe obstetric morbidity in the United States. Obstet Gynecol. 2009; 113(6):1299-1306.

4. Villar J, Carroli, G, Wojdyla D, et al; World Health Organization Antenatal Care Trial Research Group. Preeclampsia, gestational hypertension and intrauterine growth restriction, related or independent conditions. Am J Obstet Gynecol. 2006;194(4):921-931.

5. Leeman L, Fontaine P. Hypertensive disorders of pregnancy. Am Fam Physician. 2008;78(1):
93-100.

6. Magee LA, Helewa M, Moutquin JM, von Dadelszen P; Hypertension Guideline Committee; Strategic Training Initiative in Research in the Reproductive Health Sciences (STIRRHS) Scholars. Diagnosis, evaluation, and management of the hypertensive disorders of pregnancy. J Obstet Gynaecol Can. 2008;30(3 suppl):S1-S48.

7. Buchbinder A, Sibai BM, Caritis S, et al. Adverse perinatal outcomes are significantly higher in severe gestational hypertension than in mild preeclampsia. Am J Obstet Gynecol. 2002;186(1):66-71.

8. Hauth JC, Ewell MG, Levine RJ, et al; Calcium for Preeclampsia Prevention Study Group. Pregnancy outcomes in healthy nulliparas who developed hypertension. Obstet Gynecol. 2000;95(1):24-28.

9. Magnussen EB, Vatten LJ, Smith GD, Romundstad PR. Hypertensive disorders in pregnancy and subsequently measured cardiovascular risk factors. Obstet Gynecol. 2009; 114(5):961-970.

10. Lindheimer MD, Taler SJ, Cunningham FG; American Society of Hypertension (ASH). ASH position paper: hypertension in pregnancy. J Clin Hypertens (Greenwich). 2009;11(4):214-225.

11. Roberts JM, Gammill HS. Preeclampsia: recent insights. Hypertension. 2005;46(6):
1243-1249.

12. Saudan P, Brown MA, Buddle ML, Jones M. Does gestational hypertension become pre-eclampsia? Br J Obstet Gynaecol. 1998;105 (11):1177-1184.

13. Visintin C, Mugglestone MA, Almerie MQ, et al; Guideline Development Group. Management of hypertensive disorders during pregnancy: summary of NICE guidance. BMJ. 2010;341:c2207.

14. ACOG Committee on Practice Bulletins—Obstetrics. Clinical Management Guidelines for Obstetrician–Gynecologists. Diagnosis and management of preeclampsia and eclampsia: ACOG practice bulletin No. 33. Obstet Gynecol. 2002;99:159-167.

15. Parazzini F, Bortolus R, Chatenoud L, et al; Italian Study of Aspirin in Pregnancy Group. Risk factors for pregnancy-induced hypertension in women at high risk for the condition. Epidemiology. 1996;7(3):306-308.

16. Hjartardottir S, Leifsson BG, Geirsson RT, Steinthorsdottir V. Recurrence of hypertensive disorder in second pregnancy. Am J Obstet Gynecol. 2006;194(4):916-920.

17. Barton JR, O’Brien JM, Bergauer NK, et al. Mild gestational hypertension remote from term: progression and outcome. Am J Obstet Gynecol. 2001;184(5):979-983.

18. Brown MA, Mackenzie C, Dunsmuir W, et al. Can we predict recurrence of pre-eclampsia or gestational hypertension? BJOG. 2007; 114(8):984-993.

19. Bellomo G, Venanzi S, Saronio P, et al. Prognostic significance of serum uric acid in women with gestational hypertension. Hypertension. 2011;58(4):704-708.

20. Hawkins TL, Roberts JM, Mangos GJ, et al. Plasma uric acid remains a marker of poor outcome in hypertensive pregnancy: a retrospective cohort study. BJOG. 2012;119(4):484-492.

21. National Institute for Health and Clinical Excellence. Hypertension in pregnancy: the management of hypertensive disorders during pregnancy. www.nice.org.uk/nicemedia/live/13098/50418/50418.pdf. Accessed April 16, 2012.

22. Koopmans CM, Bijlenga D, Groen H, et al. Induction of labour versus expectant monitoring for gestational hypertension or mild pre-eclampsia after 36 weeks’ gestation (HYPITAT): a multicentre, open-label randomised controlled trial. Lancet. 2009;374(9694):979-988.

23. Caughey AB, Sundaram V, Kaimal AJ, et al. Maternal and neonatal outcomes of elective induction of labor. Evid Rep Technol Assess (Full Rep). 2009;(176):1-257.

24. Shennan A, Hezelgrave N. An economic analysis of induction of labour and expectant monitoring in women with gestational hypertension or pre-eclampsia at term (HYPITAT trial). BJOG. 2010;117(13):1575-1576.

25. Abalos E, Duley L, Steyn DW, Henderson-Smart DJ. Antihypertensive drug therapy for mild to moderate hypertension during pregnancy. Cochrane Database Syst Rev. 2007 Jan 24;(1):CD002252.

26. Nabhan AF, Elsedawy MM. Tight control of mild-moderate pre-existing or non-proteinuric gestational hypertension. Cochrane Database Syst Rev. 2011 Jul 6;(7):CD006907.

27. Duley L, Gülmezoglu AM, Henderson-Smart DJ. Magnesium sulphate and other anticonvulsants for women with preeclampsia. Cochrane Database Syst Rev. 2003;(2):CD000025.

28. Kraft MD, Btaiche IF, Sacks GS, Kudsk KA. Treatment of electrolyte disorders in adult patients in the intensive care unit. Am J Health Syst Pharm. 2005;62(16):1663-1682.

29. FamilyDoctor.org. Pregnancy-induced hypertension (updated 2010). http://familydoctor.org/familydoctor/en/diseases-conditions/pregnancy-induced-hypertension.printerview
.all.html. Accessed April 16, 2012.

30. Zamorski MA, Green LA. NHBPEP report on high blood pressure in pregnancy: a summary for family physicians. Am Fam Physician. 2001; 64(2):263-270.

31. Hofmeyr GJ, Duley L, Atallah A. Dietary calcium supplementation for prevention of pre-eclampsia and related problems: a systematic review and commentary. BJOG. 2007;114(8): 933-943.

32. Ferrazzani S, De Carolis S, Pomini F, et al. The duration of hypertension in the puerperium of preeclamptic women: relationship with renal impairment and week of delivery. Am J Obstet Gynecol. 1994;171(2):506-512.

33. Beardmore KS, Morris JM, Gallery ED. Excretion of antihypertensive medication into human breast milk: a systematic review. Hypertens Pregnancy. 2002;21(1):85-95.

34. Wilson BJ, Watson MS, Prescott GJ, et al. Hypertensive diseases of pregnancy and risk of hypertension and stroke in later life: results from cohort study. BMJ. 2003;326(7394):845.

In patients with severe PIH, an NST ultrasound assessment of fetal growth and amniotic fluid volume and umbilical artery Doppler velocimetry should be performed at diagnosis to evaluate for placental dysfunction.^6,21 If all test results are normal, the ultrasound and umbilical artery Doppler velocimetry need not be repeated more frequently than every two weeks, and the NST no more than once per week.¹³

Treatment/Management and Follow-Up

Regular prenatal monitoring to assess for worsening of PIH and/or development of preeclampsia is key to management. Figure 1² outlines an algorithm for managing PIH, which is guided by the severity of the condition. Patients with mild PIH can be managed with weekly outpatient visits and assessed for signs and symptoms of preeclampsia, monitoring of fetal movements, weight, blood pressure measurements, and urine and blood tests.²

At each visit, it is important to instruct patients to report immediately any of the following symptoms: new-onset severe headache, visual changes, epigastric or right upper quadrant pain, nausea or vomiting, difficulty breathing or chest tightness, as well as vaginal bleeding, decreased fetal movements, or uterine contractions.^6,14

Generally, expectant management with delivery at term is recommended for women with mild PIH.² Vaginal delivery (or cesarean delivery, if indicated) is recommended at 37 weeks or when fetal maturity is confirmed; and at 34 weeks if fetal or maternal distress is evident.^2,6

Findings from the Hypertension and Preeclampsia Intervention Trial At Term (HYPITAT),²² an open-label, randomized clinical trial in women with PIH or mild preeclampsia, suggested an association between induction of labor between 36 and 41 weeks’ gestation and improved maternal outcomes (specifically, reduced risk for severe hypertension), compared with expectant management. Similarly, in a literature review by Caughey et al,²³ results from nine randomized controlled trials indicated a reduced risk for cesarean delivery in women who underwent induction of labor, compared with expectant management. Rates of “successful” induction of labor (ie, procedures resulting in vaginal rather than cesarean delivery) were greater in women with higher parity, a favorable cervix, and earlier gestational age.

Based on data from the HYPITAT trial,²² a cost-effectiveness analysis of induction of labor compared with expectant management revealed an 11% reduction in the average cost in delivery that followed induction of labor, compared with expectant management, in women with PIH or mild preeclampsia.²⁴ Caughey et al²³ reported similar savings, particularly when induction of labor was performed at 41 weeks’ gestation.

If induction of labor is being considered in a woman with an unfavorable cervix, administration of prostaglandins is recommended to enhance cervical ripening.⁶

Medication

Pregnant women should be advised to discontinue previously prescribed ACE inhibitors, angiotensin receptor blockers, or thiazide diuretics, which are associated with congenital abnormalities, intrauterine growth restriction, and/or neonatal nephropathy.^5,6,13,21

Antihypertensive medication is not recommended for women with mild to moderate PIH, as it does not appear to improve outcomes. Evidence was found insufficient in a 2007 Cochrane review to determine the potential impact of antihypertensive medications for treatment of mild to moderate PIH on clinical outcomes such as preterm birth, infant mortality, and infant size relative to gestational age.²⁵ A similar review conducted in 2011, with primary outcomes that included severe preeclampsia, eclampsia, and maternal death or perinatal death, concluded only that further study was needed to determine how tightly blood pressure must be controlled to improve maternal and fetal outcomes in patients with PIH.²⁶

ACOG¹⁴ recommends antihypertensive therapy (eg, hydralazine, labetalol) only for women with diastolic blood pressure of 105 to 110 mm Hg or higher.^1,2 There are several recommendations from different organizations regarding the choice of antihypertensive medications for PIH. In the UK’s NICE guidance,²¹ it is recommended that patients with moderate to severe PIH take oral labetalol as first-line treatment to keep systolic blood pressure below 150 mm Hg and diastolic blood pressure between 80 and 100 mm Hg.

Like severe preeclampsia, severe PIH should be managed in an inpatient setting.^6,14 IV labetalol or hydralazine is recommended to lower the blood pressure to less than 160/110 mm Hg, although current evidence is insufficient to identify a target blood pressure.^6,26 A 2002 ACOG practice bulletin recommends one of the following:

Hydralazine 5 to 10 mg IV every 15 to 20 minutes until the desired response is achieved; or
Labetalol 20 mg IV bolus, followed by 40 mg if not effective within 10 minutes, then 80 mg every 10 minutes with maximum total dose of 220 mg.^1,14

In women who have severe PIH or who develop severe preeclampsia or eclampsia, magnesium sulfate is administered to prevent or treat seizures.¹⁴ This agent should be used during labor and for at least 24 hours postpartum.² Dosing of magnesium sulfate for this indication is 4 g IV bolus, followed by infusion of 1 g/h. It is important to monitor treated patients for signs of toxicity, including muscle weakness, loss of patellar reflexes, hypoventilation, pulmonary edema, hypotension, and bradycardia. IV calcium gluconate should be readily available for use as an antidote to life-threatening hypermagnesemia.^27,28