Hypertension in Pregnancy - Thesis Example

Hypertension in Pregnancy Introduction Hypertension during pregnancy is one of the most common complications during pregnancy and is presented in 7 to 10% of all pregnant women. It has been estimated that 10-15% of pregnancies will be complicated by hypertension1 2. Approximately up to a quarter of all antenatal admissions will be related to hypertension1. It is because of other complications for both mother and baby as it can cause intrauterine growth retardation, premature delivery, stillbirth, or postnatal problem. “In developed countries, 16.1% of maternal deaths are attributed to hypertensive diseases and they continue to be a major contributor to global maternal mortality”3. Hypertension complicating pregnancy is a major cause of preterm birth and perinatal death of the foetus. According to WHO, it is connected with it 20-33% of maternal mortality. Although any woman can suffer from this disease, experts say that this clinical picture is more common in women over 35, first-or when there are multiple pregnancies. Furthermore, the risk of hypertension during pregnancy is higher in women with obesity and diabetes. Definition of hypertension in pregnancy Hypertension is a condition characterized by a persistent increase in the level of blood pressure. During pregnancy, changes in the body are predisposed to the development of hypertension and in pregnant women because the risk of developing hypertension is higher in them than among the general population. Hypertension is a risk factor for various complications of pregnancy and ranks second in the list of causes of maternal mortality. At the same time, the diagnosis and treatment of hypertension in pregnant women requires a special approach. Hypertension usually does not give any symptoms and is diagnosed with measuring blood pressure during prenatal visits. Furthermore, in most cases, complications for the mother and the unborn child are minimal provided that adequate control is followed. In pregnant women, hypertension occurs with a frequency of 4-8%, which is a very high incidence, especially if we take into account the young age of most new mothers. This high incidence of hypertension during pregnancy is, first of all, due to the changes that occur in pregnant women. During pregnancy a woman's body adjusts to the new conditions of functioning, which include life support and development of the foetus. The cardiovascular system of pregnant women undergoes changes. There occurs an increased blood volume and the physiology of the placental circulatory system – this is necessary to ensure child development. In pregnant women, blood volume increases by 25-30%, which, apart from providing nutrition to the child, also allows women to lose some blood during childbirth, with no significant damage to health4. The heart rate also increases along with increased intra-abdominal pressure, increasing the aperture and the position change of heart in the chest due to a significant increase in the size of the uterus. Another reason is the gradual increase in weight of the pregnant woman. All of these changes increase the workload on the heart and blood vessels of pregnant women, which could lead to hypertension. However, in healthy pregnant women blood pressure does not increase significantly and in fact it might decreases slightly (from 5 to 15 mm Hg). This is due to the vasodilating action of biologically active substances released in the body of a pregnant woman. Thus, during pregnancy, normal blood pressure is formed by the interaction of factors that increase blood pressure and some other factors reduce it. Imbalance of these factors is the cause of hypertension during pregnancy. Blood pressure measurement A woman is considered hypertensive if she presents systolic blood pressure (maximum pressure) above 140 mm. Hg. and/or diastolic blood pressure (low pressure) greater than 90 mm. Hg. “Significant severe systolic hypertension of 160 mmHg or higher should be classified as a hypertensive emergency irrespective of the presence of symptoms or diastolic hypertension. This group of patients is at a significant risk of cerebrovascular events”5. In the early months of pregnancy there is a tendency to have low blood pressure due to changes secondary to placental hormones. This can result in the affected women getting dizzy and fainting during pregnancy. The most common issue during the first trimester of pregnancy is the fall in blood pressure even in hypertensive women prior to pregnancy. This can be dangerous because it could mask a previous high blood pressure and impair their differentiation with preeclampsia superimposed pregnancy6. There is a specific way of measuring blood pressure in pregnant women. Blood pressure should be measured after 10 minutes of rest, sitting with inflatable handle tensiometer at heart level. If high blood pressure is detected, measurement should be repeated after 4 hours of rest to be confirmed. Many times the stress of medical consultation can raise the blood pressure which is normalized after a few hours. In the latter case, the elevation is usually only of systolic blood pressure. Risk of hypertension during pregnancy The risk to the mother and baby depends on the type of hypertension and its severity. The patient's situation prior to pregnancy depends upon her blood pressure, her gestational week in which hypertension arises, etc. In fact, the majority of women tend to have successful pregnancies without too many complications. The risk of hypertension during pregnancy is determined by the negative impact of high blood pressure on the circulatory system of the mother and foetus. As mentioned above, hypertension of pregnancy is the second leading cause of maternal mortality. Hypertension carries a high risk in pregnant women because, firstly, high blood pressure can lead to structural changes of blood vessels in the during pregnancy, which in turn leads to the disruption of blood supply to tissues and organs. The syndrome of preeclampsia/eclampsia, the main element of hypertension in pregnancy, is characterized by impaired blood flow and kidney damage. It should be noted that eclampsia carries a high risk to pregnant women. Other complications of hypertension during pregnancy may include: retinal detachment, impaired blood supply to the brain. Secondly, high levels of blood pressure in pregnant women have a negative effect on the foetus: an increased risk for the placenta, the risk of endometrial bleeding, and the onset of massive postpartum haemorrhage. Hypertensive disorders of pregnancy Hypertension of pregnancy is raised blood pressure during pregnancy. Hypertension is regarded as a persistent elevation of systolic blood pressure above 140 mm Hg and diastolic blood pressure above 90 mm Hg in women with normal blood pressure before pregnancy. Previously, increased blood pressure by 15 mm Hg (not even reaching 140/90) was considered hypertension. In our time, in such cases, the diagnosis of hypertension is not intended, but women with such an increase in pressure require close medical supervision. Thus, there may be some types of hypertension during pregnancy. Chronic hypertension before pregnancy: It appears hypertension before 20 weeks gestation. Induced hypertension or preeclampsia pregnancy – It develops as a result of pregnancy and gradually reduces after delivery. Chronic hypertension on preeclampsia which is added: It appears as hypertension before 20 weeks of gestation and is then complicated by pregnancy-induced hypertension or preeclampsia. Transient or gestational hypertension - Transient hypertension, also known as gestational hypertension, usually appears late in pregnancy. It is mild or moderate, without proteinuria and disappears after delivery. Chronic hypertension before pregnancy Hypertension is a chronic disease characterized by an increase in blood pressure levels above 140/90 mm. Hg. It is diagnosed before pregnancy or a prenatal visit before 20 weeks of gestation. In general, this disease is characterized in that the patient knows their disease earlier, has several pregnancies and because hypertension persists after delivery. It is more common in multiparous women (with several previous deliveries). It is characterized by moderate to severe blood pressure and may or may not have increased values ??of blood uric acid. It is not often present and may have seizures or no association with renal damage. On the other hand it does not produce liver damage and no thrombocytopenia (decreased platelet count). Due to the effect of pregnancy hormones, it is common for blood pressure to get to normal in the first half of pregnancy, but still it should be maintained by antihypertensive medication in doses lower than those prior to pregnancy. Hypertension in 90% of cases is of unknown cause and only 10% of cases are secondary to other diseases such as diabetes, kidney disease, heart and autoimmune diseases among others. In cases of women with severe hypertension whose blood pressure is greater than 160/110 mm.Hg. more often you add to this disease a condition called preeclampsia, which is associated with increased health risks such as maternal or foetal heart failure, renal failure, placental abruption, preterm delivery, intrauterine growth retardation and/or seizures. Induced hypertension or preeclampsia pregnancy Preeclampsia, or toxaemia of pregnancy, is a disease of pregnancy that can affect 5% to 8% of pregnant women. The diagnosis of preeclampsia is established when there is hypertension and oedema (fluid retention) with proteins in the urine after 20 weeks of gestation, at delivery or after birth. Less often, preeclampsia appears before 20 weeks of pregnancy, as in cases of gestational trophoblastic disease (hydatidiform mole) or antiphospholipid syndrome (thrombophilia). Preeclampsia can be mild, moderate or severe, depending on blood pressure and protein loss in urine and its progression can be very slow or appear abruptly in late pregnancy. The illness resolves with delivery to be scheduled based on gestational age and state of maternal-foetal health. The earlier the onset of preeclampsia, the greater the risks to mother and baby are. In most cases preeclampsia appears in the last weeks of pregnancy and with proper management of obstetric physician, rest, healthy diet and monitoring of the baby's health, there is no significant risk to the health of the mother and baby. In cases of severe preeclampsia, there are risks of involvement in major organs maternal and placental changes that may have important consequences on both the mother and baby's health, including risks in the lives of both. For this reason, in cases of severe preeclampsia birth is advised as soon as possible, even running risks of prematurity important in the new-born. Preeclampsia is associated with arterial vasoconstriction, causing a decrease in blood supply to major maternal organs such as kidneys, liver, brain and placenta. As a result there is a decrease in the arrival of food and oxygen to the baby that prevents adequate intrauterine growth, favors a decrease in the volume of amniotic fluid, and in extreme cases can cause abruptio placenta, associated with many risks in the baby's health. Fluid retention and oedema associated with preeclampsia is due to decreased blood protein and alterations in the capillaries, which allows the liquid outlet to the tissue and also removal of proteins in urine. Chronic hypertension with superimposed preeclampsia This appears before 20 weeks of gestation and more frequently in multiparous women and is characterized by producing severe hypertension and increased blood uric acid. This picture is dangerous because hypertension may have seizures, kidney damage and liver damage, as well as thrombocytopenia (low platelets). Transient hypertension or gestational hypertension Transient or gestational hypertension occurs after 36 weeks of gestation in both primiparous and multiparous women. Hypertension is generally moderate, and no increase in uric acid levels. It is frequently associated with seizures and no kidney damage or liver, or thrombocytopenia (low platelets in blood). Treatment and prevention of hypertension during pregnancy Treatment of hypertension during pregnancy is a difficult and responsible task. Therefore, the basis for any type of treatment should be a close cooperation between patient and physician. In the treatment of hypertension during pregnancy, as well as in the treatment of hypertension in general, the following methods are used: non-pharmacological treatment and medication. Drug-free treatment, i.e. treatment without drugs is the most appropriate method of treatment of hypertension during pregnancy, since many drugs used in treating the disease can be dangerous to the foetus. Drug treatment of hypertension during pregnancy should be under the supervision of a physician specialist and only with the use of safe drugs. Pathophysiology and the effect of hypertension on the placenta Hypertension and maternity diabetes are the pregnancy complications that are known to be significantly reflected in the placenta both by using the microscope and without using it. Because of the enate vasospasm, it has been shown that the placental blood flow in the uterus is decreased in an abnormal state of pregnancy called preeclampsia7. Due to reduced flow of blood in the uterus, it circuitously leads to the narrowing foetal stem arteries, which has been often connected with the changes seen in pre-eclamptic women’s placentae. So foetal hypoxia is also result due to enate vasospasm. Foetal hypoxia may eventually result in foetal distress and foetal death according to8. Some studies of the present time have shown and demonstrated the clear relationship between retarded foetal growth and the combined placental mosaicism9. Other studies have estimated that seventy per cent of the extra foetal deaths in women with hypertension are as a result of large placental infarctions, noticeably small placental size10. Furthermore, inadequate placentation may be associated with the histopathological changes pertaining to limited placental mosaicism, and therefore with the retro placental ischemia11. The microscopic anatomy of placenta of mothers affected with hypertension have shown a significant increase in cytol knot formation, cytotrophoblastic cellular development, development of endothelial lining of capillaries, stromal pathology, calcification and hyalinization. Upon conducting the autopsy, Genset reported in 1992 that stromal pathology and undue cytol knot formation are considered to be in generalized form as unchanging results of overall diminution of foetal insertion in the placenta. On microscopic observation of the anatomy and placentae, evidence of cytotrophoblastic cellular dysplasia (i.e., the abnormal increase in the number of cells) and patchy necrosis of the villous syncytiotrophoblastic cells are most evident in the group studies as compared to the others12. The earlier deviations from the normal order contributing to the complications of gestational hypertension is a condition of early placentation (abnormal intrusion of the spiral arteries uterus, lacking in size & that did not adequately suffuse the placenta), the consequences are ischemic placenta (sufficient oxygen and nutrients are not received by the placenta in the form of blood). As a reaction to this, ischemia gives rise to an excess of vasoconstrictor factors whose objective is to cut down the calibre of arterioles & subsequently enhance the perfusion pressure. The pervasive effect of this is the high blood pressure. The situation is further worsened by the hypertension irregularities related to the ischemic placenta’s flow of toxic contents, which changes the vessel wall. Nephritic vascular lesions are also formed, liver (thrombotic micro angiopathy), brain disorders which results in disturbances from normal functioning & hematologic (disseminated intravascular coagulation, thrombocytopenia) by action on the constituents of blood caused by the toxins. Placenta in hyper tensed mothers age more rapidly than it does in case of a normal pregnancy conditions. This early maturing occurs when blood vessels in placenta are damaged by the high blood pressure. As a result of rapid aging, the nutrition and oxygen supply to the baby can be compromised. A sufficient amount of blood is required to be circulated to the placenta. According to the Mayo Clinic, high blood pressure decreases this amount of blood flow which restricts the nutrients to travel through the placenta, and as a result foetal growth is limited and falls back leading to possible low birth weight in a child. Placenta may possibly detach itself from the uterus in case of severe hypertension. Consequently excessive bleeding and haemorrhage may result which needs to be treated immediately. This also prevents the baby from getting adequate supply of oxygen and nutrients to remain alive. By the medical treatment and other techniques gestational hypertension is very much treatable. Still, renormalizing the blood does not necessarily reduces the danger of abruptio placenta disorder, and also do not reduce growth retardation within the womb. Sometimes the highly undesirable degree of arterial hypertension requires the termination of pregnancy. Neonatal outcome in children Pregnancies that are affected by hypertension have been accepted to have more eminent rates of neonatal morbidity than those pregnancies with normal blood pressure13. Higher rates of prematurity and lower birth weights have been seen in the offspring of women affected with arterial hypertension during pregnancy as compared to healthy pregnancies. Temporizing treatment should be performed to lengthen maternity and to gain time, which may result in increased perinatal survival, as evidenced in many cases. Close observation of maternal and foetus is conducted at definite intervals and delivery is suggested for aggravating maternal and foetal conditions. Under such conditions, babies require special care during the neonatal period14. Pregnancies with hypertension disorders are known to be qualified by an increased rate of premature births, LBW and VLBW infants, as compared to the healthy ones. The presence or absence of albuminuria does not matter and in this case, it is true regardless of this fact xiii. The complete amount of LBE and VLBW is not accounted for by the prematurity exclusively, there are contributing factors as described. Reduced utero-placental results due to gestational hypertension and, thereby resulting in the marred and retarded foetal growth. In fact, when GA at birth is considered, a high rate of SGA infants was found and then either premature birth or restriction of growth within the womb or a combination thereof are responsible for the noticeably low birth weight. Restriction of the foetal growth is however arguable and not always present. According to a more recent study pregnancies complicated by PE are often related with the high SGA rates, affirming the strong influence of maternal albuminuria on foetal outcome. Higher rates of placental deficiency may explain this. Two subtypes of preeclampsia occur along with the preterm PE, high rate of SGA and the persisting hypoperfusion model and term PE showing a normally functioning placenta with lower rate of SGA. A hypothesis was tested that hypertension complicated by severe foetal growth retardation must be considered as a preeclampsia matching placental hypoperfusion model. Under such circumstances when a premature birth delivery is required as a result of extremely intense foetal growth, the occurrence of albuminuria is expected. Hence, it may be concluded that the diagnostic criteria for PE should include foetal growth restriction even in the absence of albuminuria when thirty two weeks’ gestational age is to be considered. A particular age group of women affected with preeclampsia was studies and the similar perinatal opposing results in patients who grew severe preeclampsia and those who grew severe hypertension without albuminuria15. In both cases the risk of premature delivery was increased to a significant extent & the delivery of SGA infants. They argued that albuminuria might have developed if a premature delivery wasn’t required. Furthermore, studies from the present times have also indicated that the birth weight is normal in most cases of term PE and LGA infants are more than anticipated. Therefore this suggests that the placental dysfunction is not present or plays a very small role in the term preeclamptic pregnancies. High rate of LGA infants were found only in patients with uncomplicated chronic hypertension13. Gestational hypertension in the early pregnancy period was often described as having related with a low birth weight infants and lower gestational age at delivery when compared with both late gestational hypertension and preeclampsia. This has further raised the question whether factors other than albuminuria could be the cause of adverse pregnancy outcome next to maternal hypertension. Findings have shown that maternal hypertension has the adverse effects on the child16. Neonatal morbidity is more importantly raised but not solely due to more premature deliveries (worsened maternal or foetal conditions) and IUGR in hypertensive pregnancy. It directly affects both full-term and preterm babies, but the neonatal morbidity seems associated with preterm new-born babies only. Treatment of hypertension has been connected with the significantly improved foetal outcome. However, prevention of mid pregnancy abortions also played a vital part in this. Such treatments also reduced severe hypertension and side-effects were completely normal and as much as expected. More findings have proved that when the pregnancies affected by hypertension have been carefully observed the neonatal mortality rate is relatively lower17. But the relative incidence of neonatal morbidity & instrumental delivery is higher, in general, than in the hospital population taken complete. Patients considered in this study were not suffering from severe degree of hypertension except a few. The treatment is sometimes associated with the infants inclined to have a slightly smaller heads at birth. Conversely, the sustained moderate level of hypertension may adversely affect the neurological status of neonate. These finding need not be considered as clinically serious with respect to their inherent nature. However, they help in drawing attention towards the supervising of these new-born children’s development during the early postnatal period to resolve these deviations. Some deviances might possibly not be evident at birth but may become apparent in later years. References Read More