40.MSAFP ALL ARE TRUE EXCEPT
A.INCREASED IN NEURAL TUBE DEFECT
B.INCREASED IN DOWN SYNDROME
C.SECRETED FROM FETAL LIVER AND YOLK SAC
D.PEAK DURING 32 WKS
ANS:INCREASED IN DOWN SYNDROME
AFP is a protein secreted by the fetal liver and excreted in the mother's blood.
Maternal testing for fetal screening
Abnormally elevated AFP in the serum of a pregnant woman can have one or more of these sources:
a problem with the fetus
a problem with the placenta
a tumor or liver disease in the woman
a normally elevated AFP in the fetus or woman (some people naturally have very high AFP)
Usual follow-up steps include (1) a prenatal ultrasound exam to look for fetal abnormalities and/or (2) measurement of AFP in amniotic fluid obtained via amniocentesis.
Maternal serum AFP (MSAFP) varies by orders of magnitude during the course of a normal pregnancy. MSAFP increases rapidly until about 32 weeks gestation, then decreases gradually. After the pregnancy ends it decreases rapidly, with a half-life of about 5 days.
Typically, MSAFP is measured in the beginning of the second trimester (14–16 weeks). It may be measured alone or as part of a package of routine prenatal screening tests, such as a triple test or quad test.
Because MSAFP test results must be interpreted according to the gestational age, they often are reported in terms of multiple of the median (MoM). Because the median is calculated from tests of other women's pregnancies at the same gestational age, in effect MoM is independent of gestational age, but depend on accurate gestational dating. A typical normal range is 0.5 to 2.0 or 2.5 MoM.
MSAFP above normal is seen in multiple gestation, when there is placental abruption, as well as in a number of fetal abnormalities, such as neural tube defects including spina bifida and anencephaly, and abdominal wall defects. Other possibility is error in the date of the gestation. Rarely, high MSAFP is due to endodermal sinus tumor (EST) or another germ cell tumor containing EST. These tumors can occur in the pregnant woman (often as an ovarian tumor) or in the fetus.
MSAFP below normal is associated with a smaller number of conditions, including Down syndrome and Trisomy 18. Diabetic patients also have lower levels.
Patients with abnormal MSAFP need to undergo detailed obstetric ultrasonography. The information is then used to decide whether to proceed with amniocentesis. Genetic counseling usually is offered when the screening test result is positive.
A.INCREASED IN NEURAL TUBE DEFECT
B.INCREASED IN DOWN SYNDROME
C.SECRETED FROM FETAL LIVER AND YOLK SAC
D.PEAK DURING 32 WKS
ANS:INCREASED IN DOWN SYNDROME
AFP is a protein secreted by the fetal liver and excreted in the mother's blood.
Maternal testing for fetal screening
Abnormally elevated AFP in the serum of a pregnant woman can have one or more of these sources:
a problem with the fetus
a problem with the placenta
a tumor or liver disease in the woman
a normally elevated AFP in the fetus or woman (some people naturally have very high AFP)
Usual follow-up steps include (1) a prenatal ultrasound exam to look for fetal abnormalities and/or (2) measurement of AFP in amniotic fluid obtained via amniocentesis.
Maternal serum AFP (MSAFP) varies by orders of magnitude during the course of a normal pregnancy. MSAFP increases rapidly until about 32 weeks gestation, then decreases gradually. After the pregnancy ends it decreases rapidly, with a half-life of about 5 days.
Typically, MSAFP is measured in the beginning of the second trimester (14–16 weeks). It may be measured alone or as part of a package of routine prenatal screening tests, such as a triple test or quad test.
Because MSAFP test results must be interpreted according to the gestational age, they often are reported in terms of multiple of the median (MoM). Because the median is calculated from tests of other women's pregnancies at the same gestational age, in effect MoM is independent of gestational age, but depend on accurate gestational dating. A typical normal range is 0.5 to 2.0 or 2.5 MoM.
MSAFP above normal is seen in multiple gestation, when there is placental abruption, as well as in a number of fetal abnormalities, such as neural tube defects including spina bifida and anencephaly, and abdominal wall defects. Other possibility is error in the date of the gestation. Rarely, high MSAFP is due to endodermal sinus tumor (EST) or another germ cell tumor containing EST. These tumors can occur in the pregnant woman (often as an ovarian tumor) or in the fetus.
MSAFP below normal is associated with a smaller number of conditions, including Down syndrome and Trisomy 18. Diabetic patients also have lower levels.
Patients with abnormal MSAFP need to undergo detailed obstetric ultrasonography. The information is then used to decide whether to proceed with amniocentesis. Genetic counseling usually is offered when the screening test result is positive.
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