Thrombin-antithrombin III complex levels in normal pregnancy with hypertensive disorders and after delivery

Article Abstract:

During the course of a normal pregnancy there are many changes in the blood coagulation system. To help characterize disorders of high blood pressure, such as preeclampsia, markers identifying damage to the blood vessel lining, clotting and clot dissolving activity have been investigated. Disorders of high blood pressure are sometimes associated with a chronic disseminated intravascular coagulation (DIC), a condition in which clotting factors are produced in excess, followed by a lack of clotting factors and severe bleeding. The mechanisms involved in upsetting the balance within the blood coagulation system are not well understood. Coagulation is activated by a cascade of events. Thrombin activates platelet cells to clump and to change fibrinogen to fibrin, the solid protein portion of a clot. Thrombin is inactivated by the inhibitor antithrombin III (AT III). The two substances combine to form a complex called the thrombin-AT III complex (TAT). TAT is a sensitive marker for the activation of the coagulation process. TAT is stable for only a few minutes, so its level reflects the status of the coagulation system at the time the blood is tested. The concentration of TAT was measured in 91 normal pregnancies and 19 women with a disorder of high blood pressure. In eight women with a normal pregnancy, the TAT was also measured before labor, and again at 60 minutes and 24 hours after delivery. TAT was also measured in 16 healthy nonpregnant women. Women in the first three months of pregnancy and normal nonpregnant women had normal TAT concentrations, which were lower than in the women who were in their second and third trimesters. The women who had a blood pressure complication had higher TAT concentrations than either those with uncomplicated pregnancies or healthy nonpregnant women. TAT concentrations were higher one hour after delivery than before the onset of labor. These levels decreased to normal 24 hours after delivery. It is concluded that AT III is increased during normal pregnancy but that its production is greater than its use. Any small increase in thrombin is inactivated by AT III causing an increase in TAT. In pregnancies complicated by a disorder of high blood pressure, the coagulation system is in chronic state of DIC, leading to a significant increase in TAT because the production of thrombin is not totally counteracted by a decreased concentration of anti-thrombin III. (Consumer Summary produced by Reliance Medical Information, Inc.)

Causes of, Physiological aspects, Blood clotting disorders, Blood coagulation disorders, Thrombin, Hypertension in pregnancy, Gestational hypertension, Disseminated intravascular coagulation, Antithrombin III

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Non-surgical treatment of ectopic pregnancy

Article Abstract:

Ectopic pregnancy, in which a fertilized egg implants in tissues other than the uterus, has increased in incidence, partly due to improved techniques for its diagnosis. Frequently, the egg implants in the Fallopian tube and begins to develop, making hCG (human chorionic gonadotropin, the hormone which is detected by pregnancy tests) as it would if implanted in the uterus. In the past, ectopic pregnancies were recognized only in the late stages, when rupture and hemorrhage occurred. Surgical removal of the egg and Fallopian tube was then appropriate and life-saving. However, with early recognition now possible, the possibility of removing the egg while maintaining the future fertility of the patient can be addressed. Conservative tubal surgery has been used, and this can allow preservation of the tube. Very conservative treatment entails observation of the patient in the hospital, as one-third of patients spontaneously miscarry or resorb the egg. Drug therapy provides a third conservative alternative and is appropriate for 30 to 40 percent of patients. Tubal function is usually retained. Methotrexate, a cytotoxic (cell-killing) agent, may be given systemically or directly to the fertilized egg if it is small and the Fallopian tube is intact. This is likely to fail if hCG levels are high or if there is a fetal heartbeat. Other pharmacologic agents include prostaglandin F-2-alpha, a type of locally-acting hormone, or highly concentrated glucose, which would strip the tissue of water. Whatever treatment is chosen, laparoscopy, the visual examination of the abdominal cavity, is necessary for diagnosis and assessment. Levels of hCG should be assessed in all patients until close to normal levels are achieved. Conservative treatment, with retention of the Fallopian tubes, is no guarantee of future fertility. Research is needed to evaluate the short- and long-term outcome following non-surgical intervention for ectopic pregnancy. (Consumer Summary produced by Reliance Medical Information, Inc.)

Care and treatment, Pregnancy, Ectopic, Ectopic pregnancy, editorial

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Screening for viral and protozoal infections in pregnancy. A review

Article Abstract:

Publicity about the potential adverse effects of cytomegalovirus (CMV) infection, toxoplasmosis (infection by Toxoplasma gondii), and parvovirus B19 infection has led pregnant women in the United Kingdom to request screening for these infections. But the value of such screening is controversial. This article reviews the laboratory and medical data available on this topic. Screening is already established for rubella (German measles), human immunodeficiency virus (HIV, the cause of AIDS), and hepatitis B virus. Because no effective prevention against or treatment for CMV in pregnant women exists, screening would be inappropriate and would simply result in heightened anxiety in those labeled at risk. Screening techniques for toxoplasmosis are not yet adequate, and prevention of fetal damage in the event of an identified infection is considered difficult. No vaccine is available to protect non-immune patients from toxoplasmosis, and behavior modification (avoidance of cat feces and uncooked meats) by pregnant women is instead recommended. Parvovirus B19 is related to a slightly increased risk of miscarriage or stillbirth but not to congenital defects, and half of all adults are immune to the infection. Screening for the virus is therefore not considered appropriate. Further research in these areas is needed, particularly in the development of appropriate vaccines and improved laboratory tests for these infections. (Consumer Summary produced by Reliance Medical Information, Inc.)

Evaluation, Infection, Testing, Pregnant women, Cytomegalovirus infections, Medical screening, Health screening, Pregnancy, Complications of, Pregnancy complications, Toxoplasmosis, Parvovirus infections

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