The most common prenatal testIt is to study the AFP. Its main problem is that positive test results are often incorrect, that is, the analysis points to the pathology, which is actually not. incorrect negative results are also possible, and the presence of really existing violations were determined. Woman spends many weeks in the repetition of tests and worries about results rather than to enjoy the precious moments of pregnancy. To avoid unnecessary worry, we want to tell you about the AFP.
Why this analysis? AFP is a natural chemical substance,produced by the liver of the child. After the amniotic fluid and the placenta, it enters the mother's blood. The concentration of AFP in the blood increases with the child. AFP is enhanced when the embryo arise medullary defects (neural) of the tube as it exits substance open spine. The concentration of AFP increases and multiple pregnancy. Children with Down syndrome AFP level is lowered. The most accurate results of this test gives between the fourteenth and eighteenth week of pregnancy. Themselves as the results are usually ready in a week after blood collection. AFP only defines an open neural tube defect in which there is the expiration of cerebrospinal fluid. Closed defect (ie, a hernia of the meninges, spinal hernia, or hydrocephalus), this test does not detect. A newer test, called »triple scan» (or »prenatal risk profile»), specifies AFP, estrogenic hormones and human placental gonadotropin (CHPG); This is a more accurate method for determination of Down syndrome than AFP, which identifies him only one patient out of five child. But even triple the scan does not detect 20 to 30% of cases of Down syndrome in the fetus of pregnant women over thirty-five years, and in 40% of cases the fetus of pregnant women under the age of thirty-five years. Some hospitals offer pregnant necessarily make the AFP test. We do not believe this test obligatory. At my seventh child, Seeds, Down's syndrome, (we did not know about it, because it does not do any AFP test or triple scanning). He's a wonderful child. His love and accept all who know him. All members of our family owes its maturation and self-improvement. In spite of everything, our lives become richer after the birth of seeds.
The thing to keep in mind. We believe that with a lot of problems linked to the AFP. Neural tube defects are extremely rare (1-2 cases per 1000 births). Most of these pregnancies end in miscarriage. The correct interpretation of the results of AFP depends on the exact definition of pregnancy. And it's not in use AFP. This test often leads to other expensive and unnecessary tests. Abnormal levels of AFP requires verification by ultrasound and / or use of amniocentesis puncture membranes. In 98% »too high» or »too low» levels are a mistake (the child no Down syndrome or spinal defect).
Рассмотрим такой пример: одной тысяче беременных женщин сделали АФП-тест, чтобы выявить одного или двух детей с дефектами нервной трубки. У 3% женщин (т.е. у тридцати) результат оказался положительным. Эти тридцать женщин подверглись еще и ультразвуковому обследованию, чтобы убедиться в неправильности результатов предыдущего анализа. Но примерно у половины из них ультразвук не дал полную информацию. Поэтому пятнадцати женщинам сделают амниоцентез, который, может быть, обнаружит ту одну, у которой ребенок имеет дефекты нервной трубки. А как же риск амниоцентеза для остальных четырнадцати нормальных детей? Ведь после этой процедуры происходят выкидыши в одном случае из двухсот. То есть один здоровый ребенок может погибнуть при выявлении тринадцати со спинномозговыми дефектами. АФП-тест является классической иллюстрацией разрушительной силы бюрократии, когда решение принимается с учетом общих требований, а не личных потребностей женщины. Мы ставим под сомнение полезность АФП-теста.
