The role of antioxidant vitamins in hypertensive disorders of pregnancy
ABSTRACT Preeclampsia (PE) is an important and a leading cause of both maternal morbidity and adverse perinatal outcomes. Despite progress in perinatal medicine for patients with an established diagnosis of PE, a therapeutic approach other than termination of pregnancy was unsuccessful. Women predisposed to PE begin pregnancy with a certain degree of endothelial dysfunction, a lesion that precedes shallow placentation. The proposed sequence of events comprises endothelial dysfunction, defective trophoblast invasion, and consequential impaired placental perfusion, immune maladaptation and inflammation. The possible link between these could be oxidative stress by excessive production of reactive oxygen species coupled with inadequate or overwhelmed antioxidant defense mechanisms. These defense mechanisms, involving antioxidant vitamins and enzyme systems, may restrain the extent of damage caused by oxidative stress. Markers of oxidative stress in women with established PE were confirmed. Accordingly, these findings support an expected beneficial effect of antioxidant therapy in the prevention of PE and other pregnancy-related disorders. Numerous studies have been carried out in order to investigate this possible and simple prophylactic and/or therapeutic approach in prevention of oxidative stress and eventual reduction of PE and its perinatal complications. In this review the role of vitamin antioxidants in prevention and treatment of PE is discussed. Despite the logic behind using antioxidant vitamins, the data, thus far, are at best conflicting.
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- "In conditions such as recurrent pregnancy loss, preeclampsia, preterm premature rupture of membranes, intrauterine growth restriction (IUGR) and fetal death oxidative stress has been suggested as causative agents. Hence, free radicals are going to provoke a switch towards a prooxidant status causing negative effects on the placenta and subsequently upon fetal growth and development . Markers of oxidative stress, such as nonprotein bound iron, have been measured in cord blood as an indicator of intrauterine ROS production. "
ABSTRACT: Fetal to neonatal transition poses a relevant threat to the newly born infant. In few minutes oxygen delivery to tissue will rise abruptly. In addition, very often aggressive therapies which include the use of oxygen are going to be necessary to assure survival of the neonate. Interestingly, the antioxidant defense system maturation pattern is not complete until the end of gestation and, therefore, preterm babies are endowed with an immature and less effective antioxidant armamentarium. Under these circumstances preterm infants are prone to oxidative stress derived serious conditions such as retinopathy of prematurity, bronchopulmonary dysplasia or intra-periventricular hemorrhage. Remarkably, human milk even in preterm mothers provides with a vast array of antioxidant substances that will undoubtedly help the infant to confront with a pro-oxidant milieu. These antioxidant properties render human milk essential for the survival of preterm infants and its use should be therefore strongly reinforced.Journal of Pediatric Biochemistry 01/2013; 3(3):169-177. DOI:10.3233/JPB-130090
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- "In conclusion, maternal hypoxia independent of maternal undernutrition promotes maternal and placental indices of oxidative stress, effects that can be prevented by maternal treatment with vitamin C in hypoxic pregnancy. Although vitamin C may prove an unsuitable candidate for therapy in pregnant women (Poston et al. 2006; Spinnato et al. 2007; Kontic-Vucinic et al. 2008; Rumbold et al. 2008; Villar et al. 2009), treatment with other antioxidants at human tolerable doses, such as with melatonin (Richter et al. 2009; Thakor et al. 2010a) or allopurinol (Derks et al. 2010), may still provide a viable clinical intervention to improve placental function and protect fetal growth in pregnancy complicated by fetal hypoxia. "
ABSTRACT: This study isolated the effects of maternal hypoxia independent of changes in maternal nutrition on maternal circulatory and placental molecular indices of oxidative stress and determined whether maternal antioxidant treatment conferred protection. Pregnant rats were subjected to normoxic pregnancy or 13% O2 chronic hypoxia for most of gestation with and without maternal treatment with vitamin C in the drinking water. Maternal hypoxia with and without vitamin C did not affect maternal food or water intake and led to a significant increase in maternal and fetal haematocrit. At gestational day 20, maternal plasma urate and L-cysteine concentrations, and placental levels of 4-hydroxynonenal and heat shock protein 70 were increased while placental heat shock protein 90 levels were decreased in hypoxic pregnancy. The induction of maternal circulatory and placental molecular indices of oxidative stress in hypoxic pregnancies was prevented by maternal treatment with vitamin C. Maternal hypoxia during pregnancy with or without vitamin C increased placental weight, but not total or compartmental volumes. Maternal treatment with vitamin C increased birth weight in both hypoxic and normoxic pregnancies. The data show that maternal hypoxia independent of maternal undernutrition promotes maternal and placental indices of oxidative stress, effects that can be prevented by maternal treatment with vitamin C in hypoxic pregnancy. While vitamin C may not be the ideal candidate of choice for therapy in pregnant women, and taking into consideration differences in ascorbic acid metabolism between rats and humans, the data do underlie that antioxidant treatment may provide a useful intervention to improve placental function and protect fetal growth in pregnancy complicated by fetal hypoxia.The Journal of Physiology 01/2012; 590(Pt 6):1377-87. DOI:10.1113/jphysiol.2011.226340 · 5.04 Impact Factor
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ABSTRACT: Objectives: To assess the plasma levels of vitamins C and E at the various stages of pregnancy and to correlate their plasma levels with the socio-demographic factors of pregnant Nigerians. Methodology: The pregnant cases (n=180) were randomly selected according to gestational ages. And the controls (n=20) were non-pregnant women of the same age. Plasma levels of both vitamins were assayed with well established laboratory methods. Results: The mean plasma vitamins C and E in the pregnant cases was lower (by 17-23%) than controls across the three trimesters, p