Pregnancy Perils

2. Monitor individuals who develop mild preeclampsia for 24-72 hours to assess for progression. If they remain stable, the decision analysis depends on the stage of pregnancy. After 32 weeks gestation, the physician can elect to continue the pregnancy while prescribing reduced activity or bed rest with or without anti-hypertensive therapy. If anti-hypertensive therapy is elected, optimal choices include the dihydropyridine class of calcium channel antagonists, centrally acting alpha 2 agonists such as clonidine, or beta-blockers.

Though diuretics appear safe, most obstetricians do not advocate their use. Most physicians choose to initiate pharmacologic therapy if preeclampsia occurs prior to 32 weeks, in order to allow further fetal development prior to delivery. Many obstetricians will induce labor if the pregnancy is beyond 36 weeks to avoid the complications of preeclampsia/eclampsia. Delivery usually resolves the syndrome of preeclampsia within a period of time that ranges from hours to days.

3. In patients with severe preeclampsia, the risks are greater. In these circumstances, physicians are more likely to induce delivery if gestation is greater than 32 weeks. However, in pregnancies beyond 36 weeks, a physician may choose to delay delivery in order to allow fetal lung maturation, using steroids while controlling blood pressure and preventing seizures with intravenous Mg2SO4. Other options include the use of intravenous labetalol, hydralazine, or even nitroprusside, while also treating the patient with phenytoin to prevent seizures.

4. The presence of the HELLP syndrome usually necessitates urgent delivery and may have prolonged effects on blood pressure, liver function, and compromised renal function after the pregnancy has ended.

As a better understanding of the pathogenesis of preeclampsia develops in the future, more selective and definitive preventive or interventional therapy is likely. As further investigation moves toward that goal, this serious health problem in an otherwise young and healthy population should be mitigated. TH

Dr. Beach is the Paul R. Stalnaker Distinguished Professor of Internal Medicine, director, Division of Nephrology and Hypertension, and scholar, John McGovern Academy of Oslerian Medicine.

References

1. Longo SA, Dola CP, Pridjian G. Preeclampsia and eclampsia revisited. South Med J. 2003 Sep;96(9): 891-899.
2. Irgens HU, Reisaeter L, Irgens LM, et al. Long-term mortality of mothers and fathers after pre-eclampsia: population based cohort study. BMJ. 2001 Nov 24;323(7323):1213-1217.
3. CLASP (Collaborative Low-dose Aspirin Study in Pregnancy) Collaborative Group. CLASP: a randomised trial of low-dose aspirin for the prevention and treatment of pre-eclampsia among 9364 pregnant women. Lancet. 1994;343:619-629.
4. Hofmeyer GJ, Atallah AN, Duley L. Calcium supplementation during pregnancy for preventing hypertensive disorders and related problems. Cochrane Database Sys Rev. 2000;3:CD001059.
5. Collins R, Yusuf S, Peto R. Overview of randomised trials of diuretics in pregnancy. Br Med J (Clin Res Ed). 1985 Jan 5;290 (6461):17-23.
6. Magee LA, Ornstein MP, von Dadelszen P. Fortnightly review: management of hypertension in pregnancy. BMJ. 1999 May 15;318 (7194):1332-1336.
7. Lucas MJ, Leveno KJ, Cunningham FG. A comparison of magnesium sulfate with phenytoin for the prevention of eclampsia. N Engl J Med. 1995 Jul 27;333 (4):201-205.
8. Belfort MA, Anthony J, Saade GR, et al. A comparison of magnesium sulfate and nimodipine for the prevention of eclampsia. N Engl J Med. 2003 Jan 23;348 (4):304-311.
9. Levine RJ, Karumanchi SA. Circulating angiogenic factors in preeclampsia. Clin Obstet Gynecol. 2005 Jun;48(2):372-386.
10. Jeyabalan A, Novak J, Danielson LA, et al. Essential role for vascular gelatinase activity in relaxin-induced renal vasodilation, hyperfiltration, and reduced myogenic reactivity of small arteries. Circ Res. 2003 Dec 12;93(12):1249-1257. Epub 2003 Oct 30.
11. Savvidou MD, Hingorani AD, Tsikas D, et al. Endothelial dysfunction and raised plasma concentrations of asymmetric dimethylarginine in pregnant women who subsequently develop pre-eclampsia. Lancet. 2003 May 3;361(9368):1511-1517.
12. Noris M, Todeschini M, Cassis P, et al. L-arginine depletion in preeclampsia orients nitric oxide synthase toward oxidant species. Hypertension. 2004 Mar;43(3):614-622. Epub 2004 Jan 26.
13. Levine RJ, Maynard SE, Qian C, et al. Circulating angiogenic factors and the risk of preeclampsia. N Engl J Med. 2004 Feb 12;350 (7):672-683. Epub 2004 Feb 5.
14. Vu H, Ianosi-Irimie M, Danchuk S, et al. Resibufogenin corrects hypertension in a rat model of human preeclampsia. Exp Biol Med (Maywood). 2006 Feb;231(2):215-220.