Gestational Hypertension

Also indexed as: Hypertension of Pregnancy, Nonproteinuric Gestational Hypertension, Preeclampsia (Nonproteinuric), Pregnancy-Induced Hypertension (Nonproteinuric)

Gestational hypertension (GH) is high blood pressure that develops after the twentieth week of pregnancy and returns to normal after delivery, in women with previously regular blood pressure.

GH may be an early sign of either preeclampsia or chronic hypertension. If these complications do not develop, or if chronic hypertension develops but remains mild, the outcome of pregnancy is usually good for both the mother and newborn. GH has been shown to occur more frequently in women who are obese1 or in those who are glucose-intolerant.2 3 4

Checklist for Gestational Hypertension

Rating Nutritional Supplements Herbs
3Stars Calcium
Magnesium		  
1Star Zinc  
3Stars Reliable and relatively consistent scientific data showing a substantial health benefit.
2Stars Contradictory, insufficient, or preliminary studies suggesting a health benefit or minimal health benefit.
1Star An herb is primarily supported by traditional use, or the herb or supplement has little scientific support and/or minimal health benefit.

What are the symptoms of gestational hypertension? Symptoms, which appear after the twentieth week of pregnancy, include swelling of the face and hands, visual disturbances, headache, high blood pressure, and a yellow discoloration of the skin and eyes.

How is it treated? Conventional treatment for GH includes bed rest, restriction of sodium intake, medicines to reduce high blood pressure, and possibly hospitalization for observation. Sometimes intravenous magnesium solutions may be recommended;however, the definitive conventional treatment is termination of the pregnancy by induced delivery or cesarean section.

Dietary changes that may be helpful: Unlike salt restriction in primary hypertension, a low-salt diet has not been shown to have a significant effect in reducing high blood pressure during pregnancy.5 6 7 As a result, salt restriction is not recommended to women with GH.8

Increased consumption of fish was associated with reduced risk of GH in one preliminary study.9 In this study, the incidence of hypertension during pregnancy was significantly higher in women from communities with lower consumption of fish and lower in women from communities with high fish consumption.

Lifestyle changes that may be helpful: In GH, regular checkups during pregnancy and after delivery are needed for the prevention and early detection of preeclampsia and chronic hypertension.10 11 12

Job stress (lack of control over work pace and the timing and frequency of breaks) has been reported to be detrimental; therefore, reducing job stress may be beneficial in the prevention of GH.13 In a preliminary study, women exposed to high job stress were found to be at greater risk of developing GH than were women with low job stress.14

The common practice of prescribing bed rest for women with GH has been questioned by some researchers.15 In the few studies examining this issue, results have been inconsistent.16 17 While one controlled study found that bed rest reduced progression of GH to severe hypertension,18 evidence is currently insufficient to determine whether bed rest reduces blood pressure in women with GH.

Nutritional supplements that may be helpful: Calcium deficiency has been implicated as a possible cause of GH.19 20 In two preliminary studies, women who developed GH were found to have significantly lower dietary calcium intake than did pregnant women with normal blood pressure.21 22 Calcium supplementation has significantly reduced the incidence of GH in preliminary studies23 and in many,24 25 26 27 28 29 though not all,30 double-blind trials. Calcium supplements may be most effective in preventing GH in women who have low dietary intake of calcium. The National Institutes of Health (NIH) recommends an intake of 1,200 to 1,500 mg of calcium daily during normal pregnancy.31 In women at risk of GH, studies showing reduced incidence have typically used 2,000 mg of supplemental calcium per day,32 33 34 35 36 37 without any reported maternal or fetal side effects.38 39 Nonetheless, many doctors continue to suggest amounts no higher than 1,500 mg per day.

Magnesium deficiency has also been implicated as a possible cause of GH.40 41 42 Dietary intake of magnesium is below recommended levels for many women during pregnancy.43 44 Magnesium supplementation has been reported to reduce the incidence of GH in preliminary45 and many double-blind trials.46 47 In addition to preventing GH, magnesium supplementation has also been reported to reduce the severity of established GH in one study.48 Amounts used in studies on GH range from 165 to 365 mg of supplemental magnesium per day.

Zinc supplementation (20 mg per day) was reported to reduce the incidence of GH in one double-blind trial studying a group of low-income Hispanic pregnant women who were not zinc deficient.49

Antioxidant levels in the blood of women with GH appear to be reduced in some,50 51 52 but not all,53 preliminary studies. No studies have yet been conducted evaluating the effects of antioxidant supplementation on the incidence or severity of GH.

Are there any side effects or interactions? Refer to the individual supplement for information about any side effects or interactions.

References:

1. Ros JS, Cnattingius S, Lipworth L. Comparison of risk factors for preeclampsia and gestational hypertension in a population-based cohort study. Am J Epidemiol 1998;147:1062–70.

2. Caruso A, Ferrazzani S, De Carolis S, et al. Gestational hypertension but not pre-eclampsia is associated with insulin resistance syndrome characteristics. Hum Reprod 1999;14:219–23.

3. Innes KE, Wimsatt JH. Pregnancy-induced hypertension and insulin resistance: evidence for a connection. Acta Obstet Gynecol Scand 1999;78:263–84.

4. Solomon CG, Carroll JS, Okamura K, et al. Higher cholesterol and insulin levels in pregnancy are associated with increased risk for pregnancy-induced hypertension. Am J Hypertens 1999;12:276–82.

5. Franx A, Steegers EA, de Boo T, et al. Sodium-blood pressure interrelationship in pregnancy. J Hum Hypertens 1999;13:159–66.

6. van der Maten GD. Low sodium diet in pregnancy: effects on maternal nutritional status. Eur J Obstet Gynecol Reprod Biol 1995;61:63–4.

7. Steegers EA, Van Lakwijk HP, Jongsma HW, et al. (Patho)physiological implications of chronic dietary sodium restriction during pregnancy; a longitudinal prospective randomized study. Br J Obstet Gynaecol 1991;98:980–7.

8. Moutquin JM, Garner PR, Burrows RF, et al. Report of the Canadian Hypertension Society Consensus Conference: 2. Nonpharmacologic management and prevention of hypertensive disorders in pregnancy. CMAJ 1997;157:907–19.

9. Popeski D, Ebbeling LR, Brown PB, et al. Blood pressure during pregnancy in Canadian Inuit: community differences related to diet. CMAJ 1991;145:445–54.

10. Mounier-Vehier C, Equine O, Valat-Rigot AS, et al. Hypertensive syndromes in pregnancy. Physiopathology, definition and fetomaternal complications. Presse Med 1999;28:880–5 [in French].

11. Mounier-Vehier C, Equine O, Valat-Rigot AS, et al. Hypertensive syndromes in pregnancy. Diagnosis and therapy. Presse Med 1999;28:886–91 [in French].

12. Jerie P. Hypertension and its treatment in pregnancy. Cas Lek Cesk 1998;137:467–72 [review] [in Czech].

13. Wergeland E, Strand K. Work pace control and pregnancy health in a population-based sample of employed women in Norway. Scand J Work Environ Health 1998;24:206–12.

14. Marcoux S, Berube S, Brisson C, Mondor M. Job strain and pregnancy-induced hypertension. Epidemiology 1999;10:376–82.

15. Goldenberg RL, Cliver SP, Bronstein J, et al. Bed rest in pregnancy. Obstet Gynecol 1994;84:131–6 [review].

16. Herrera JA. Nutritional factors and rest reduce pregnancy-induced hypertension and pre-eclampsia in positive roll-over test primigravidas. Int J Gynaecol Obstet 1993;41:31–5.

17. Mathews DD. A randomized controlled trial of bed rest and sedation or normal activity and non-sedation in the management of non-albuminuric hypertension in late pregnancy. Br J Obstet Gynaecol 1997;84:108–14.

18. Crowther CA, Bouwmeester AM, Ashurst HM. Does admission to hospital for bed rest prevent disease progression or improve fetal outcome in pregnancy complicated by non-proteinuric hypertension? Br J Obstet Gynaecol 1992;99:13–7.

19. Leela R, Yasodhara P, Ramaraju MBBS, Ramaraju LA. Calcium and magnesium in pregnancy. Nutr Res 1991;11:1231–6.

20. Prada JA, Ross R, Clark KE. Hypocalcemia and pregnancy-induced hypertension produced by maternal fasting. Hypertension 1992;20:620–6.

21. Marcous S, Brisson J, Fabia J. Calcium intake from dairy products and supplements and the risk of preeclampsia and gestational hypertension. Am J Epidemiol 1991;133:1226–72.

22. Ortega RM, Martinez RM, Lopez-Sobaler AM, et al. Influence of calcium intake on gestational hypertension. Ann Nutr Metab 1999;43:37–46.

23. Bucher HC, Guyatt GH, Cook RJ, et al. Effect of calcium supplementation on pregnancy-induced hypertension and preeclampsia: a meta-analysis of randomized controlled trials. JAMA 1996;275:1113–7.

24. Bucher HC, Guyatt GH, Cook RJ, et al. Effect of calcium supplementation on pregnancy-induced hypertension and preeclampsia: a meta-analysis of randomized controlled trials. JAMA 1996;275:1113–7.

25. Lopez-Jaramillo P, Narvaez M, Weigle RM, Yepez R. Calcium supplementation reduces the risk of pregnancy-induced hypertension in an Andes population. Br J Obstet Gynaecol 1989;96:648–55.

26. Cong K, Chi S, Lui G. Calcium supplementation during pregnancy for reducing pregnancy induced hypertension. Chin Med J 1995;108:57–9.

27. Purwar M, Kulkarni, H, Motghare V, Dhole S. Calcium supplementation and prevention of pregnancy induced hypertension. J Obstet Gynaecol Res 1996;22:425–30.

28. Belizán JM, Villar J, Gonzalez L, et al. Calcium supplementation to prevent hypertensive disorders of pregnancy. N Engl J Med 1991;325:1399–405.

29. Sanchez-Ramos L, Briones DK, Kaunitz AM, et al. Prevention of pregnancy-induced hypertension by calcium supplementation in angiotensin II-sensitive patients. Obstet Gynecol 1994;84:349–53.

30. Levine RJ, Hauth JC, Curet LB, et al. Trial of calcium to prevent preeclampsia. N Engl J Med 1997;337:69–76.

31. NIH Consensus Development Panel on Optimal Calcium Intake. Optimal calcium intake. Nutrition 1995;11:409–17.

32. Moutquin JM, Garner PR, Burrows RF, et al. Report of the Canadian Hypertension Society Consensus Conference: 2. Nonpharmacologic management and prevention of hypertensive disorders in pregnancy. CMAJ 1997;157:907–19.

33. Cong K, Chi S, Lui G. Calcium supplementation during pregnancy for reducing pregnancy induced hypertension. Chin Men J 1995;108:57–9.

34. Bucher HC, Guyatt GH, Cook RJ, et al. Effect of calcium supplementation on pregnancy-induced hypertension and preeclampsia: a meta-analysis of randomized controlled trials. JAMA 1996;275:1113–7.

35. Lopez-Jaramillo P, Narvaez M, Weigel RM, Yepez R. Calcium supplementation reduces the risk of pregnancy-induced hypertension in an Andes population. Br J Obstet Gynaecol 1989;96:648–55.

36. Purwar M, Julkarni H, Motghare V, Dhole S. Calcium supplementation and prevention of pregnancy induced hypertension. J Obstet Gynaecol Res 1996;22:425–30.

37. Sanchez-Ramos L, Briones DK, Kaunitz AM, et al. Prevention of pregnancy-induced hypertension by calcium supplementation in angiotensin II-sensitive patients. Obstet Gynecol 1994;84:349–53.

38. Moutquin JM, Garner PR, Burrows RF, et al. Report of the Canadian Hypertension Society Consensus Conference: 2. Nonpharmacologic management and prevention of hypertensive disorders in pregnancy. CMAJ 1997;157:907–19.

39. Cong K, Chi S, Lui G. Calcium supplementation during pregnancy for reducing pregnancy induced hypertension. Chin Men J 1995;108:57–9.

40. Wynn A, Wynn M. Magnesium and other nutrient deficiencies as possible causes of hypertension and low birthweight. Nutr Health 1988;6:69–88.

41. Conradt A. Current concepts in the pathogenesis of gestosis with special reference to magnesium deficiency. Z Geburtshilfe Perinatol 1984;188:49–58 [review] [in German].

42. Leela R, Yasodhara P, Ramaraju MBBS, Ramaraju LA. Calcium and magnesium in pregnancy. Nutr Res 1991;11:1231–6.

43. Makrides M, Crowther CA. Magnesium supplementation in pregnancy. Cochrane Database Syst Rev 2000;2:CD000937 [review].

44. Wynn A, Wynn M. Magnesium and other nutrient deficiencies as possible causes of hypertension and low birthweight. Nutr Health 1988;6:69–88.

45. Wynn A, Wynn M. Magnesium and other nutrient deficiencies as possible causes of hypertension and low birthweight. Nutr Health 1988;6:69–88.

46. Li S, Tian H. Oral low-dose magnesium gluconate preventing pregnancy induced hypertension. Chung Hua Fu Chan Ko Tsa Chih 1997;32:613–5 [in Chinese].

47. D’Almeida A, Caretr JP, Anatol A, Prost C. Effects of a combination of evening primrose oil (gamma linolenic acid) and fish oil (eicosapentaenoic + docosahexaenoic acid) versus magnesium, and versus placebo in preventing pre-eclampsia. Women Health 1992;19:117–31.

48. Rudnicki M, Frolich A, Rasmussen WF, McNair P. The effect of magnesium on maternal blood pressure in pregnancy-induced hypertension. A randomized double-blind placebo-controlled trial. Acta Obstet Gynecol Scand 1991;80:445–50.

49. Hunt IF, Murphy NJ, Cleaver AE, et al. Zinc supplementation during pregnancy: effects on selected blood constituents and on progress and outcome of pregnancy in low-income women of Mexican descent. Am J Clin Nutr 1984;40:508–21.

50. Loverro G, Greco P, Capuano F, et al. Lipid peroxidation and antioxidant enzyme activity in pregnancy complicated by hypertension. Eur J Obstet Gynecol Reprod Biol 1996;70:123–7.

51. Gratacos E, Casals E, Deulofeu R, et al. Lipid peroxide and vitamin E patterns in pregnant women with different types of hypertension in pregnancy. Am J Obstet Gynecol 1998;178:1072–6.

52. Oostenbrug GS, Mensink RP, van Houwelingen AC, et al. Pregnancy-induced hypertension: maternal and neonatal plasma lipid-soluble antioxidant levels and its relationship with fatty acid unsaturation. Eur J Clin Nutr 1998;52:754–9.

53. Gratacos E, Casals E, Deulofeu R, et al. Lipid peroxide and vitamin E patterns in pregnant women with different types of hypertension in pregnancy. Am J Obstet Gynecol 1998;178:1072–6.