I'm sorry that you had to find us, but glad that you did. Hopefully, I can help with some of your questions. Multiples of the median (MoM) is a statistical term that (in theory) makes it easy to compare test results between different facilities. In practice, this is not always the case. I wonder if you could find out from your OB what percentile your MoM of 0.45 puts you in. When I was told that my PAPP-A was low, I was given a report that had three values- an absolute value, an MoM, and a percentile.
In your case, an MoM of 0.45 probably puts you right above the 5th percentile. That means that you have a lower PAPP-A level than about 95 out of 100 pregnant women. As your OB told you, a PAPP-A level less than the 10th percentile is considered low and has been associated with an increased risk of pregnancy complications (loss before 24 weeks, gestational hypertension, preeclampsia, IUGR, preterm birth). As PAPP-A levels fall the risk for complications increases, but only slightly at about the 5th percentile (it is women below the 1st percentile like me, that have the most risk). However, the good news for you is that most women with low PAPP-A do not have ANY complications. For instance in one study (American Journal of Obstetrics and Gynecology (2004) v191, p1446-51), less than 4% of women with PAPP-A levels below the 5th percentile ended up with PE. Another way to think about the numbers is asking how likely you are to get PE compared to a woman with a "normal" level of PAPP-A? The answer is that at the 5th percentile you have about a 1.5 fold chance of getting PE compared to a normal pregnancy- that means less than 2 times as likely. So, odds are in your favor
Your OB is correct, since you had a successful first pregnancy, you are less likely to develop PE than if you had not been pregnant before. But there are women who get PE for the first time in a second pregnancy. Usually, PE in subsequent pregnancies is less extreme and later than in first pregnancies.
Since your having your 20 week scan at a hospital, I would assume that you will be having a very detailed scan that would include Doppler imaging of the umbilical vessels. But you might want to confirm that with your OB since you are worried about it. I don't think that any ultrasound findings actually predict or can be used to diagnose PE. However, PE can affect blood flow to the placenta and therefore the baby. That is why once PE is diagnosed, many women get periodic ultrasounds to check blood flow and baby's growth. In addition, since low PAPP-A is associated with IUGR, your baby's growth should be followed closely- this is also best done by ultrasound.
I am not very familiar with the QUAD screen but I don't think that it will tell you any more than you already know- that you are at slightly higher risks for several pregnancy complications. The QUAD screen can only confirm this and not disprove it.
And now for your real question- and unfortunately, I am not going to give you the answer you seek- there is currently no way to accurately predict who is going to get preeclampsia. And there has not been any intervention that can prevent or delay the onset of preeclampsia. Over the years, people have tried many different diets, supplements, exercise and nothing has proven useful (with the exceptions of treating underlying conditions like immune disorders or clotting disorders and losing weight in obese women). Some women take low-dose aspirin on their doctor's advice, but rigorous studies have proven that it is not effective for most women with PE. Some women with underlying blood clotting disorders take heparin or low-molecular weight heparin, but again there is no evidence that in women without clotting disorders that this is effective. Since the only cure for PE is to deliver the placenta (and therefore the baby), OBs can only carefully watch for signs that PE is starting and then make care decisions based on how mild/severe the PE is and how far along the pregnancy is.
As for seeing an MFM- In your shoes, I would talk to your OB about how comfortable he/she is in dealing with a higher risk pregnancy. Since the low PAPP-A level does not guarantee that you are going to experience any complications, you may be fine to continue to see your OB. I would ask your OB how many cases of PE has he/she dealt with in the past? I would ask your OB what signs and symptoms would be concerning enough that you would be referred to an MFM? I would want to know who that MFM is. And where they are located. And I would want to know exactly what extra monitoring you will be doing and when. Please have your OB describe to you the signs and symptoms of preeclampsia and HELLP syndrome. And then I would also ask your OB what signs and symptoms does he/she want reported right away, no matter the time of day. And what is concerning enough that you should head straight to Labor and Delivery. If your OB is not able to answer these questions and have a conversation with you about your concerns, than you might want to think about seeing another OB or an MFM. Remember you are the best advocate for both you and your baby.
Good luck and I hope that the rest of your pregnancy is free from complication! Let me know if you have any other questions.
Diana, happily married since 2007.
Miscarriage at 10 weeks (June 2009).
DD at 30+0 weeks weighing 2lbs 9oz (October 2010) due to PE and IUGR. Today, a happy and healthy toddler.