At 18 weeks, the AFP level is high in the triple marker test, but the 4D scan is normal. Why?

Hello,

Welcome to icliniq.com.

The AFP is basically alpha-fetoprotein which is produced by your baby's body only. The triple test is done to look for or predict any anomalies or defects in the baby. It is a screening test. AFP is to predict the presence of neural tube defects (spine and brain). AFP values are measured in MOM (multiples of median), that is, how many times the value you got is higher than the general population. So if it is 2 to 2.5 times higher, that means the AFP value is raised. So if you can send me the printed reports, I can explain better. Also, if the AFP value is high, an anomaly scan will be done to rule out and structural defects. So do not worry. Kindly send me the photo of the presented report so that I can guide you better. I hope this was helpful.

Hello,

Welcome back to icliniq.com.

Please do not panic. Let me explain to you the results of various tests which have been done and the significance of each:

1) Triple test (this test is outdated and no more done). It was used to detect any anomalies in the baby using three hormones (beta-hCG, AFP, and estradiol). It is used to rules out chromosomal diseases and neural tube defects.

2) Quadruple test is a standard test done during four to six months of pregnancy. It measures AFP (you have tested positive for high AFP). This is used as a screening for neural tube defects. This hormone can be increased in the mother's blood if the baby has open spine defects. It can also be increased in pregnancy with wrong dates, twins, problems with the placenta, other abdominal wall defects, sometimes in chromosomal anomalies, and sometimes it may be seen in normal pregnancy. Hence an increased AFP is only a screening test that tells whether your baby is at high risk of these defects and does not confirm the presence of these defects. Once you test positive for AFP, confirmatory tests are of two types. Targeted ultrasound scan which has been done for you and shows no spine or any other fetal anomalies and amniocentesis if you are still not satisfied or your doctor still doubts the presence of defects, amniotic fluid from around the baby is taken using a needle and ultrasound and tested. This is the confirmatory test (but it is invasive and has a very small risk of miscarriage). In hCG, Inhibin A, and estradiol, used to screen for chromosomal anomalies, you have tested negative.

3) Ultrasound (4D and targeted scan) both these scans show no anomalies in the baby. This rules out 90% chances of any anomalies in the baby.

But your scan shows you have a bicornuate uterus (small septum in your uterus), which may lead to preterm delivery. Your screening test for high blood pressure in pregnancy is positive. So there are chances of developing high blood pressure (preeclampsia) during pregnancy which can be controlled by medication and regular BP (blood pressure) checkups (this condition can also cause raised AFP). So these are the options you have.

1) Repeat your targeted scan at 20 weeks and a fetal echo at 18 weeks. If there are no anomalies, then you can continue the pregnancy. The chances of the baby being normal are 90 to 95%.

2) If you want to be 100% sure, go for an amniocentesis. This will help rule out any cause of raised AFP there might be. But since it is an invasive test, there is a 1% chance of miscarriage (but if some by an experienced doctor, chances are very low).

So do not be stressed and do not panic. These tests are only to keep you aware of the risk and not confirmatory.

I hope this was helpful.