Low Papp-A in pregnancy

Finding out you have low Papp-A levels in pregnancy can feel really overwhelming.

You might feel scared or unsure about what it all means for you, your pregnancy and your baby. You may not have ever heard of Papp-A or have any idea it was being tested for (that’s sadly common).

What is low Papp-A?

PAPP-A stands for Pregnancy Associated Plasma Protein-A (don’t worry, you don’t need to remember that!). It’s a hormone that is made by the placenta in pregnancy. It is measured as part of the combined screening blood test offered between 11-14 weeks. In this screening, they measure your baby’s nuchal fold measurement (a bit of fluid at the back of their neck) , and look at 4 hormone markers in your blood to determine your risk of having a baby with Down’s, Edwards, or Patau’s syndrome. Papp-A is one of the markers they test for, and a reading below 0.4 MoM is considered low. However, a low Papp-A level alone is NOT specifically linked with Down’s syndrome. Its what we call an incidental finding - i.e we’re not looking for it specifically, but if we find it, we’ll act on the information.

What are the risks with low Papp-A?

It’s important to remember that most women with low Papp-A levels will have straightforward pregnancies and healthy babies. However, the research suggests that a low Papp-A level is associated with:

• Small babies (Birth weight under 5th + 10th centile)

• Pre-eclampsia

• Pre-term birth

These findings were from a large, good quality study (Morris et al, 2017) which makes the findings more reliable, but the authors of the study do state that the ability to predict the [above] complications was very low.

One small study found a higher rate of stillbirth, but only for those babies that were small (Smith et al, 2004). You can read these studies in full with the links below if you want more information.

What does having low Papp-A mean for my pregnancy?

If you are told you have low PAPP-A, it may impact your pregnancy in several ways. It may cause anxiety, especially if you didn’t know it was being tested for. You may be offered Aspirin 150mg to take once a day until 36 weeks of pregnancy. Aspirin is used to reduce the risk of developing pre-eclampsia and associated small babies.

You may be offered growth scans. Because evidence suggests more mums with low Papp-A have smaller or growth restricted babies, scans are offered from 32 (or 35 weeks, depending on your area).

You might be offered induction of labour around 40 weeks, dependant on your local hospital policy. It’s important to know that there is no national guidance around low Papp-A and birth, so guidelines often vary from area to area. To date, there is no data to suggest that induction of labour improves outcomes for women with low Papp-A. Induction of labour has a big impact on your birth and choices in birth, so it’s important to understand the process and it’s risks and benefits before you decide if that is right for you.

You might find using the BRAIN tool helpful when you are faced with making decisions in your pregnancy. Find out more about the BRAIN tool here.

Lastly, read Jade’s birth story here - she was diagnosed with Low Papp-A in early pregnancy and kindly shares her experience with us. Remember, most people with low Papp-A go on to have healthy pregnancies and births and you are likely to also :).

If you want more of my support, with this or any other issue in your pregnancy, you can book a one-to-one appointment with me here. I’m a midwife who is passionate about supporting women and birthing people to have positive experiences, and to equip you with the knowledge to feel confident going into birth.

References:

Morris RK, Bilagi A, Devani P, Kilby MD. Association of serum PAPP-A levels in first trimester with small for gestational age and adverse pregnancy outcomes: systematic review and meta-analysis. Prenat Diagn. 2017 Mar;37(3):253-265. doi: 10.1002/pd.5001. Epub 2017 Feb 17. PMID: 28012202.

Smith GCS, Crossley JA, Aitken DA, et al. First-Trimester Placentation and the Risk of Antepartum Stillbirth. JAMA. 2004;292(18):2249–2254. doi:10.1001/jama.292.18.2249