Maternal effects Several aspects of maternal adaptation to pregnancy are affected by dysfunction of placenta. Maternal arteries fail to transform into low-resistance vessels (expected by 22–24 weeks of gestation). This increases vascular resistance in fetoplacental vascular bed eventually leading to reduction in metabolically active mass of placenta like a vicious cycle. Fetal effects<unk>  can affect the fetus, causing fetal distress.<unk>  may cause oligohydramnios, preeclampsia, miscarriage or stillbirth.<unk>  is most frequent cause of asymmetric IUGR. Fetal metabolic changes Metabolic changes occurring in uteroplacental<unk> : Substrate Change Glucose Decreases in proportion to degree of fetal hypoglycemia Amino acids * Decrease in branched chain amino acids (valine, leucine, isoleucine), serine and lysine. * Increase in hydroxyproline * Glycine:Valine ratio increases in amniotic fluid * Increase in ammonia in amniotic fluid (positive correlation with ponderal index) Fatty acids * Decrease in long-chain polyunsaturated fatty acids * Decrease in overall fatty acid transport via umbilical cord Oxygen and Carbon dioxide * Degree of hypoxemia is proportional to villous damage * Hypercapnia, acidemia, hypoxemia and hyperlacticemia in proportion to hypoxemia Fetal hormonal changes Decrease in overall thyroid function is correlated with fetal hypoxemia. Serum glucagon, adrenaline, noradrenaline levels increase, eventually causing peripheral glycogenolysis and mobilization of fetal hepatic glycogen stores. Fetal hematologic changes Fetal hypoxemia triggers erythropoietin release. This stimulates RBC production from medullary and extramedullary sites and eventually results in polycythemia. Oxygen carrying capacity of blood is thus increased. Prolonged tissue hypoxemia may cause early release of erythrocytes from maturation sites and thus count of nucleated RBCs in blood increases. These factors, increase in blood viscosity, decrease in cell membrane fluidity and platelet aggregation are important precursors in accelerating placental vascular occlusion. Fetal immunological changes There is decrease in immunoglobulin, absolute B-cell counts and total WBC count. T-helper and cytotoxic T-cells are suppressed in proportion of degree of acidemia. These conditions lead to higher infection susceptibility of infant after delivery. Fetal cardiovascular changes There is decrease in magnitude of umbilical venous volume flow. In response to this, the proportion of umbilical venous blood diverted to fetal heart increases. This eventually leads to elevation of pulmonary vascular resistance and increased right ventricular afterload. This fetal cerebral redistribution of blood flow is an early response to<unk> . Blood flow is selectively redirected to the myocardium, adrenal glands, and in particular to the brain in a brain-sparing effect. In late stage, the redistribution becomes ineffective, there is decrease in cardiac output, ineffective preload handling and elevation of central venous pressure. This deterioration in circulation may ultimately lead to tricuspid<unk>  and death of the fetus. Peripheral circulatory disturbances also accompany these central circulatory changes. Fetal behavioral changes Chronic hypoxemia leads to delay in all aspects of CNS maturation. With worsening fetal hypoxemia, there is decline in fetal activity. With further hypoxemia, fetal breathing ceases. Gross body movements and tone decrease further. Fetal heart rate decreases due to spontaneous deceleration due to direct depression of cardiac contractility. This leads to intrauterine fetal death. Risk of later metabolic disease According to the theory of thrifty phenotype,<unk>  triggers epigenetic responses in the fetus that are otherwise activated in times of chronic food shortage. If the offspring actually develops in an environment rich in food it may be more prone to metabolic disorders, such as obesity and type II diabetes.
Placental insufficiency
Placental disease
Fetal-maternal haemorrhage
Foetal cerebral redistribution
Retained placenta
Placental expulsion
Umbilical cord compression
Fetal distress