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.

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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.

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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.

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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.

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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.

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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.

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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.

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For chronic hypertension in pregnancy, the American Society of Hypertension¹⁰ has recommended several agents. There is no consensus on which medication is most appropriate (see Table 2^10,13).

Patient Education

Patient education is an important aspect of caring for women with PIH. The American Academy of Family Physicians^29,30 provides a comprehensive patient education resource that defines the hypertensive disorders in pregnancy, explains the symptoms and signs of severe hypertension or preeclampsia, and describes appropriate diagnostic tests, monitoring, and treatment options. (See http://familydoctor.org/familydoctor/en/diseases-conditions/pregnancy-induced-hypertension.printerview.all.html.)

Patients who are considering pregnancy should be counseled to maintain a healthy weight prior to and during pregnancy. Adequate dietary calcium can reduce the risk for PIH, and calcium supplementation has been shown to reduce the risk for preeclampsia, especially in women at high risk.³¹ The Society of Obstetricians and Gynaecologists of Canada recommends low-dose aspirin (75 mg/d) at bedtime for high-risk women, starting before pregnancy, or upon diagnosis of pregnancy to prevent preeclampsia.⁶ Although there is insufficient evidence to recommend dietary salt restriction, excess salt can increase fluid retention and possibly blood pressure. Patients should be urged to attend all scheduled prenatal visits and to review the warning signs and symptoms of severe hypertension and preeclampsia at each visit.

Mode of delivery may be discussed and will depend on the severity of hypertension, presence of preeclampsia, and fetal well-being. Vaginal delivery at term is considered optimal unless there are indications for cesarean delivery. Induction of labor may be considered at term in patients with PIH. Those with severe preeclampsia who may require preterm delivery must be prepared for potential issues associated with prematurity.

Follow-Up and Prognosis

Patients with PIH should be evaluated postpartum for persistent hypertension. Blood pressure in patients with PIH usually normalizes by day 7 postpartum.³² If blood pressure elevation persists past 12 weeks postpartum, the patient’s diagnosis is revised to chronic hypertension and managed accordingly.

In the patient with persistent hypertension who chooses breastfeeding, it is important to select an antihypertensive medication with low transfer into breast milk. Many β-adrenergic antagonists and calcium channel antagonists are considered “compatible” with breastfeeding by the American Academy of Pediatrics.³³

In addition to the potential for recurrent PIH in subsequent pregnancies, women with PIH are at increased risk for hypertension later in life, and findings from several large cohort studies suggest increased cardiovascular risk in patients with hypertensive pregnancies.^16,34 Magnussen et al,⁹ who followed more than 15,000 mothers of singleton infants for several years postpartum, found that those who experienced hypertensive disorders (particularly recurrent hypertensive disorders) during pregnancy were more likely than normotensive women to subsequently develop diabetes, dyslipidemia, and hypertension. Women who remained normotensive while pregnant generally had lower BMI measurements than those who experienced PIH or preeclampsia.

Conclusion

Hypertensive disorders commonly develop during pregnancy. It is important to diagnose and classify PIH during routine prenatal visits. Once the diagnosis is made, patients must be monitored closely for increasing blood pressure or development of preeclampsia. Urine protein testing is a key clinical test to detect preeclampsia, and positive findings on a random urine protein dipstick should be confirmed and quantified with a 24-hour urine collection.

In addition to undergoing frequent blood pressure measurements and urine protein tests, patients should be asked about signs and symptoms that suggest preeclampsia. Women with mild PIH can be managed as outpatients with prenatal visits at least weekly, followed by delivery at term. Severely hypertensive patients are managed in the hospital with antihypertensive medications and prompt delivery at 34 weeks’ gestation or beyond, should maternal or fetal distress become evident.