Intrauterine hypoxia (also known as fetal hypoxia) occurs when the fetus is deprived of an adequate supply of oxygen. It may be due to a variety of reasons such as prolapse or occlusion of the umbilical cord, placental infarction, maternal diabetes (prepregnancy or gestational diabetes) and maternal smoking. Intrauterine growth restriction may cause or be the result of hypoxia. Intrauterine hypoxia can cause cellular damage that occurs within the central nervous system (the brain and spinal cord). This results in an increased mortality rate, including an increased risk of sudden infant death syndrome (SIDS). Oxygen deprivation in the fetus and neonate have been implicated as either a primary or as a contributing risk factor in numerous neurological and neuropsychiatric disorders such as epilepsy, attention deficit hyperactivity disorder, eating disorders and cerebral palsy. Presentation
Maternal Consequences
Complications arising from intrauterine hypoxia are some of the leading causes of preeclampsia. Preeclampsia is a hypertensive disorder that occurs during the second trimester (after the 20th week of pregnancy) resulting from a poorly perfused placenta. Studies from the World Health Organization show that globally, about 14% (50,000- 750000 women) of maternal deaths annually are caused by preeclampsia and eclampsia.During pregnancy, women with preeclampsia faces serious risk of damage to vital organs such as the kidneys, liver, brain, and the blood system. This hypertensive disorder may also cause damage to the placenta leading to issues such as premature births, miscarriages, placental abruption, or even stillbirths. In some cases, preeclampsia can eventually lead to stroke and organ failure.
While some previous studies have suggested that carbon monoxide from cigarette smoke may have a protective effect against preeclampsia, a recent study conducted by the Genetics of Pre-Eclampsia Consortium in the United Kingdom found that smokers were five times more likely to develop pre-eclampsia.Nicotine alone has been shown to be a teratogen which affects the autonomic nervous system, leading to increased susceptibility to hypoxia-induced brain damage. Maternal anemia in which smoking has also been implicated is another factor associated with IH/BA. Smoking by expectant mothers causes a decrease in maternal nucleated red blood cells, thereby reducing the amount of red blood cells available for oxygen transport.Utero-placental hypoxia is associated with abnormal placental implantation, impaired vascular remodeling and vascular diseases. It is also associated with pregnancies complicated by gestational hypertension, intrauterine growth restriction, and pre-eclampsia.Post-placental hypoxia is associated with mechanical obstructions of the umbilical cords, reduced uterine artery flow, progressive fetal cardiac failure, and genetic anomalies.The perinatal brain injury occurring as a result of birth asphyxia, manifesting within 48 hours of birth, is a form of hypoxic ischemic encephalopathy. Diagnosis
Treatment
Treatment of infants with birth asphyxia by lowering the core body temperature is now known to be an effective therapy to reduce mortality and improve neurological outcome in survivors, and hypothermia therapy for neonatal encephalopathy begun within 6 hours of birth significantly increases the chance of normal survival in affected infants.There has long been a debate over whether newborn infants with birth asphyxia should be resuscitated with 100% oxygen or normal air.