The maternal alpha-fetoprotein (MSAFP) test is a common test that measures the level of AFP in the mother's blood. Its main purpose is to screen for neural tube defects; it's also used to help in screening for chromosome abnormalities in the fetus. AFP is a protein produced naturally by the fetus and passed into the mother's bloodstream. The function of AFP is uncertain, but it may help tranport materials in the blood.
The triple test is also a method of screening maternal blood to detect fetal spinal defects and chromosome abnormalities, especially Down syndrome. It consists of lab tests performed on one blood sample between the 15th and 20th week of pregnancy to analyze three substances normall present in pregnant women:
1. MSAFP
2. HCG (human chorionic gonadotropin), a hormone produced in the placenta
3. Estriol, an estrogen produced by both the fetus and the placenta
Importnant: What else can elevated levels mean??
~ Your pregnancy is not dated correctly. AFP levels normally increase during the first 20 weeks of pregnancy. If the gestational age of your fetus is actually older than was estimated, then AFP levels will be higher than expected.
~ You are carrying twins. Your AFP levels will be elevated because there are two babies producing the AFP instead of one.
~ You fetus has a less common "open" birth defect that can also cause an increase in AFP. For example, if the baby's adominal wall does not close completely, there will be an opening through which more AFP will leak out. Some rare skin conditions or intestinal blockages also increase AFP levels.
~ A fetal blood vessel in the placenta has bled, allowing fetal cells containing high amounts of AFP to cross over to the mother.
~ There is a defect in the placenta wall. This also enables more AFP to cross over to the mother. Placental wall defects sometimes occur in pregnant women who have high blood pressure or who contract other illnesses that damage the placenta.
~ The initial interpretation of your test results did not consider your weight, race or the presence of diabetes, all of which affect AFP levels.
If your AFP levels are high?
Some Dr.'s will recommend repeating the AFP or triple test to compare the results with those of your first test. Most Dr's will also recommend an ultrasound to view the fetus. If the ultrasound can't determine the elevated results, the next step in often an amniocentesis to check the amniotic fluid level of AFP. Of every 50 pregnancies investigated with amniocentesis after a high result or triple test, 48 will have normal levels of amniotic fluid AFP, which indicate that the risk of neural tube defect is low.
What can cause low levels of AFP?
The most common reason is an incorrect estimation of the age of the fetus. Some fetuses with Down syndrome, trisomy 13 or trisomy 18 have a low level of AFP. Maternal diabetes can also cause decreased levels.
What if the levels are low?
The next step would be to do an ultrasound to access the age of the fetus and development of the fetus and or to determine whether it has died. Again, if the ultrasound does not determine anything, amniocentesis will be offered.
Do you want a prenatal screening done?
Before you say "yes":
~ Ask yourself how you will feel if the results are abnormal.
~ If the results are abnormal, will you want to continue with more prenatal testing to find out whether your fetus has a congenital condition.
~ Do you need to ask the cost first, and whether insurance will cover it?
Before you say "No":
~ Would you want to know during your pregnancy whether there is a problem affecting your fetus's health?
~ Will you worry more not knowing?
~ If a problem was identified prenatally, could anything be done to improve the health of your fetus?
These are just a few things to consider. If you have any questions or concerns, please feel free to ask me and I'll do the best I can to give you the answers. Please note ~ I am not a Dr. I just work in a medical laboratory and have had experience and understanding related to these tests.
The triple test is also a method of screening maternal blood to detect fetal spinal defects and chromosome abnormalities, especially Down syndrome. It consists of lab tests performed on one blood sample between the 15th and 20th week of pregnancy to analyze three substances normall present in pregnant women:
1. MSAFP
2. HCG (human chorionic gonadotropin), a hormone produced in the placenta
3. Estriol, an estrogen produced by both the fetus and the placenta
Importnant: What else can elevated levels mean??
~ Your pregnancy is not dated correctly. AFP levels normally increase during the first 20 weeks of pregnancy. If the gestational age of your fetus is actually older than was estimated, then AFP levels will be higher than expected.
~ You are carrying twins. Your AFP levels will be elevated because there are two babies producing the AFP instead of one.
~ You fetus has a less common "open" birth defect that can also cause an increase in AFP. For example, if the baby's adominal wall does not close completely, there will be an opening through which more AFP will leak out. Some rare skin conditions or intestinal blockages also increase AFP levels.
~ A fetal blood vessel in the placenta has bled, allowing fetal cells containing high amounts of AFP to cross over to the mother.
~ There is a defect in the placenta wall. This also enables more AFP to cross over to the mother. Placental wall defects sometimes occur in pregnant women who have high blood pressure or who contract other illnesses that damage the placenta.
~ The initial interpretation of your test results did not consider your weight, race or the presence of diabetes, all of which affect AFP levels.
If your AFP levels are high?
Some Dr.'s will recommend repeating the AFP or triple test to compare the results with those of your first test. Most Dr's will also recommend an ultrasound to view the fetus. If the ultrasound can't determine the elevated results, the next step in often an amniocentesis to check the amniotic fluid level of AFP. Of every 50 pregnancies investigated with amniocentesis after a high result or triple test, 48 will have normal levels of amniotic fluid AFP, which indicate that the risk of neural tube defect is low.
What can cause low levels of AFP?
The most common reason is an incorrect estimation of the age of the fetus. Some fetuses with Down syndrome, trisomy 13 or trisomy 18 have a low level of AFP. Maternal diabetes can also cause decreased levels.
What if the levels are low?
The next step would be to do an ultrasound to access the age of the fetus and development of the fetus and or to determine whether it has died. Again, if the ultrasound does not determine anything, amniocentesis will be offered.
Do you want a prenatal screening done?
Before you say "yes":
~ Ask yourself how you will feel if the results are abnormal.
~ If the results are abnormal, will you want to continue with more prenatal testing to find out whether your fetus has a congenital condition.
~ Do you need to ask the cost first, and whether insurance will cover it?
Before you say "No":
~ Would you want to know during your pregnancy whether there is a problem affecting your fetus's health?
~ Will you worry more not knowing?
~ If a problem was identified prenatally, could anything be done to improve the health of your fetus?
These are just a few things to consider. If you have any questions or concerns, please feel free to ask me and I'll do the best I can to give you the answers. Please note ~ I am not a Dr. I just work in a medical laboratory and have had experience and understanding related to these tests.
