Pre-eclampsiaIntroduction

 Pregnant women should take several thousand IU/day of vitamin D3 and aim for a serum 25(OH)D level of over 40 ng/mL (100 nmol/L).

Preeclampsia is a medical condition in which hypertension arises in pregnancy (pregnancy-induced hypertension) in association with significant amounts of protein in the urine.

Preeclampsia is an important indicator of future cardiovascular disease for the mother and adverse health effects of the infant then and later in life.

It affects up to 10% of pregnancies in the United States.

Observational studies have found inverse correlations between serum 25-hydroxyvitamin D [25(OH)D] level and risk of preeclampsia. Based on these and a study of vitamin D supplementation by pregnant women, it appears that pregnant women should take several thousand IU/day of vitamin D3 and aim for a serum 25(OH)D level of over 40 ng/mL (100 nmol/L).

Preeclampsia may develop from 20 weeks gestation (it is considered early onset before 32 weeks, which is associated with increased morbidity). Preeclampsia may also occur up to six weeks post-partum. Preeclampsia occurs in as many as 8% of pregnancies in the United States1.

Compared with hospitalizations without any hypertensive disorders, the risk of severe obstetric complications ranged from 3.3 to 34.8 per 1000 in the United States for hospitalizations with eclampsia/severe preeclampsia2.

Mothers who develop preeclampsia are at increased risk for other cardiovascular diseases34.

Preeclampsia is also a leading cause of maternal death during pregnancy5.

In Denmark, “Children born at term exposed to preeclampsia had an increased risk of a variety of diseases, such as endocrine, nutritional, and metabolic diseases (incidence rate ratio, 1.6; 95% confidence interval, 1.5-1.7), and diseases of the blood and blood-forming organs (incidence rate ratio, 1.5; 95% confidence interval, 1.3-1.8)6.” 

Preeclampsia occurs in 3-14% of pregnancies and is defined by maternal hypertension with proteinurea, generally associated with edema, coagulation abnormalities, and disseminated intravascular coagulation. The conditions can lead to eclampsia, characterized by hyperreflexia and convulsions. Several organs are afflicted by the condition, most importantly the liver and kidneys.

The direct cause of preeclampsia is unknown, but the initial events are linked to abnormalities of placentation. This implies abnormalities in trophoblast invasion and in physiological alterations of placental vessels required for adequate perfusion of the placenta, which leads to ischemia. The mechanisms that link the ischemic placenta to endothelial lesions and to stimulation of vasoconstrictors and inhibition of vasodilators are still subject of speculation7

Preeclampsia, a pregnancy-specific syndrome characterized by hypertension, proteinuria and oedema, resolves on placental delivery. Its pathogenesis is thought to be associated to a hypoxic placenta. Placental hypoxia is responsible for the maternal vascular dysfunction via the increased placental release of anti-angiogenic factors such as soluble flt1 and endoglin. These soluble receptors bind VEGF, PLGF and TGFbeta1 and 3 in the maternal circulation, causing endothelial dysfunction in many maternal tissues8.

Preeclampsia is a risk factor for preterm and/or small-for-gestational-age birth. This risk is related to endothelial dysfunction, which can be assessed by measurement of maternal plasma cellular fibronectin (cFN). “Elevated cFN in women with preeclampsia was associated with an increased risk of both preterm and SGA births (odds ratio, 3.0; confidence interval [CI], 1.0-8.7) compared with women with preeclampsia without elevated cFN. The risk of preterm birth was 14.7-fold higher (CI, 8.1-26.7) and the risk of SGA was 6.8-fold higher (CI, 3.5-13.1) in women with preeclampsia, hyperuricemia, and elevated cFN compared with normotensive women9.” 

The hypothesis that vitamin D could reduce the risk of preeclampsia was proposed in 2005 by Elina Hypponen based on some considerations of the mechanisms whereby vitamin D might play a role in prevention as well as a careful reading of the literature on vitamin D supplementation during pregnancy10.

Page last edited: 03 May 2011

References

  1. Roberts, J. M. Pearson, G. Cutler, J. Lindheimer, M. Summary of the NHLBI Working Group on Research on Hypertension During Pregnancy. Hypertension. 2003 Mar; 41 (3): 437-45.
  2. Kuklina, E. V. Ayala, C. Callaghan, W. M. Hypertensive disorders and severe obstetric morbidity in the United States. Obstet Gynecol. 2009 Jun; 113 (6): 1299-306.
  3. Mongraw-Chaffin, M. L. Cirillo, P. M. Cohn, B. A. Preeclampsia and cardiovascular disease death: prospective evidence from the child health and development studies cohort. Hypertension. 2010 Jul; 56 (1): 166-71.
  4. Romundstad, P. R. Magnussen, E. B. Smith, G. D. Vatten, L. J. Hypertension in pregnancy and later cardiovascular risk: common antecedents?. Circulation. 2010 Aug 10; 122 (6): 579-84.
  5. Shand, A. W. Nassar, N. Von Dadelszen, P. Innis, S. M. Green, T. J. Maternal vitamin D status in pregnancy and adverse pregnancy outcomes in a group at high risk for pre-eclampsia. BJOG. 2010 Dec; 117 (13): 1593-8.
  6. Wu, C. S. Nohr, E. A. Bech, B. H. Vestergaard, M. Catov, J. M. Olsen, J. Health of children born to mothers who had preeclampsia: a population-based cohort study. Am J Obstet Gynecol. 2009 Sep; 201 (3): 269 e1-269 e10.
  7. Irminger-Finger, I. Jastrow, N. Irion, O. Preeclampsia: a danger growing in disguise. Int J Biochem Cell Biol. 2008; 40 (10): 1979-83.
  8. Lorquet, S. Pequeux, C. Munaut, C. Foidart, J. M. Aetiology and physiopathology of preeclampsia and related forms. Acta Clin Belg. 2010 Jul-Aug; 65 (4): 237-41.
  9. Powers, R. W. Catov, J. M. Bodnar, L. M. Gallaher, M. J. Lain, K. Y. Roberts, J. M. Evidence of endothelial dysfunction in preeclampsia and risk of adverse pregnancy outcome. Reprod Sci. 2008 Apr; 15 (4): 374-81.
  10. Hypponen, E. Vitamin D for the prevention of preeclampsia? A hypothesis. Nutr Rev. 2005 Jul; 63 (7): 225-32.