I have been told I have a low PAPP-A – what is this and what does it mean?

5 things to know about PAPP-A:

1. It is a protein made by the placenta

2. Low levels are associated with placental complications, such as poor growth in the baby, high blood pressure (pre-eclampsia) and stillbirth.

3. Most women with a low PAPP-A do not get these complications, as it is just a risk rather than meaning these problems will happen

4. You will be offered aspirin to reduce the risks of these complications happening

5. You will be offered some additional scans to check the placental development and monitor the growth of the baby later in pregnancy.

What is PAPP-A and how does is affect my baby?

PAPP-A is a protein made by the placenta. It stands for pregnancy associated plasma protein A, but the name is not important. If you chose to have screening for Down’s syndrome around 12 weeks, then this protein gets measured. If you chose not to have screening for Down’s syndrome, then you won’t have had this protein measured.  

As well as being part of the Down’s syndrome screening test PAPP-A is also a useful screening test for how well the placenta has formed during the early weeks of the pregnancy. If it is low, then there is an increased risk of developing complications due to poor placental function later on in the pregnancy. This includes the risks of a baby not growing as well as it should (a small for gestational age baby, fetal growth restriction) or pre-eclampsia, which is a condition that causes high blood pressure. It can also increase the risk of stillbirth.

Although low PAPP-A is the most common protein that tends to get reported after screening for Down’s syndrome, the other proteins measured at these tests can also be associated with these complications. These include a high betaHCG on the first trimester test, or a raised AFP, inhibin or HCG on the quad test.

What if I do have low PAPP-A?

It is important to understand that if your PAPPA- A measured low, it does not mean that these complications are going to happen, it just means that the risk is higher compared to someone with a PAPP-A in the normal range. Most women with a low PAPP-A do not go on to get these complications. 

If these proteins are reported as abnormal, your midwife should explain this to you. If you are 16 weeks or less, you will be offered aspirin, 150mg to take at night until 36 weeks, as it is known that this reduces the risks of the placental complications. You may also be offered aspirin if you are over 16 weeks, although it is known that it is far less effective if started after 16 weeks compared to less than 16 weeks. You will also be offered a measurement of specific blood flow to the placenta at around 20 weeks (called a uterine artery Doppler) and then scans to monitor the growth of the baby later in the pregnancy.