Could antioxidant supplementation prevent pre-eclampsia?

Valerie A. Holmes, David R. McCance
2005 Proceedings of the Nutrition Society  
Pre-eclampsia is a disorder characterised by pregnancy-induced hypertension and new-onset proteinuria occurring in the second half of pregnancy. Worldwide, approximately 2-3% of all pregnant women develop pre-eclampsia. The condition is a major cause of maternal and fetal morbidity and mortality. Abnormal placentation is an important predisposing factor for preeclampsia, while endothelial activation appears to be central to the pathophysiological changes, possibly indicative of a two-stage
more » ... of a two-stage disorder characterised by reduced placental perfusion and a maternal syndrome. There is increasing evidence that pre-eclampsia is associated with both increased oxidative stress and reduced antioxidant defences, which has led to the hypothesis that oxidative stress may play an important role in the pathogenesis of pre-eclampsia, perhaps acting as the link in a two-stage model of pre-eclampsia. In support of this hypothesis a small, but important, preliminary study has shown a highly significant (P = 0 . 02) reduction in the incidence of pre-eclampsia in women at risk who were taking a supplement of vitamins C and E from midpregnancy. Furthermore, these findings support the hypothesis that oxidative stress is at least partly responsible for the endothelial dysfunction of pre-eclampsia. Several larger multicentre trials are currently underway to evaluate the efficacy, safety and cost benefits of antioxidant supplementation during pregnancy for the prevention of pre-eclampsia in both low-and high-risk women, including women with diabetes. The results of these trials are awaited with interest. Antioxidants: Pre-eclampsia: Oxidative Stress: Pregnancy: Diabetes Chappell et al. (1999) have reported in a small, but important, study a highly-significant reduction in the incidence of pre-eclampsia in women at risk who were taking a vitamin C and E supplement (adjusted odds ratio 0 . 39 (95 % CI 0 . 17, 0 . 90), P = 0 . 02). Antioxidant supplementation in these women has also been shown to be associated with changes in indices of oxidative stress and placental function (Chappell et al. 2002b). Primarily, the results of this trial indicate that antioxidants may be beneficial in the prevention of pre-eclampsia and support the emerging concept that oxidative stress plays a role in the pathophysiology of pre-eclampsia. Several multicentre trials are currently underway to confirm these results in larger groups of both low-risk and high-risk women. The present review gives an overview of pre-eclampsia, discusses the role of oxidative stress in the pathophysiology of this disorder and illustrates why antioxidants may play a role in pre-eclampsia prophylaxis. Pre-eclampsia Pre-eclampsia is a disorder of pregnancy characterised by pregnancy-induced hypertension ( ‡ 140 mmHg systolic and/or ‡ 90 mmHg diastolic blood pressure) and newonset proteinuria ( ‡ 300 mg protein/d) occurring in the second half of pregnancy (Brown et al. 2001) . Preeclampsia has several predisposing risk factors including: primiparity; age <20 years or > 40 years; high BMI; personal and family history of pre-eclampsia; multiple pregnancy; pre-existing medical conditions such as chronic hypertension, renal disease, autoimmune disease, antiphospholipid syndrome and diabetes mellitus (Duckitt & Harrington, 2005) . Complications of pre-eclampsia include haemolysis, elevated liver enzymes and low platelets (termed HELLP syndrome), and eclampsia, where eclampsia is characterised by one or more convulsions superimposed on pre-eclampsia. Worldwide, approximately Abbreviations: MDA, malondialdehyde; SOD, superoxide dismutase.
doi:10.1079/pns2005469 pmid:16313693 fatcat:lxrbmqkmgnda7dpljvfyfmlpsq