Placental Infarcts causing IFD

[expert@preeclampsia.org]

My name is Mia and I have chronic well controlled hypertension. Back in 2003 I conceived thru IVF and was induced at 35 wks because my BP was getting difficult to control from 32 wks on and I had trace amounts of protein in my urine (+1). The end result was a healthy baby boy weighing in at 5lb 14oz thanks to a fabulous MFS who didn't miss a beat. Before and during that pregnancy I was on Lopressor, that seemed to work to a certain degree.

Two years later I conceived spontaneously and that pregnancy ended in IFD at 34 wks just 1 day after my son scored 8/8 in a BPP. I had a different MFS who seemed to take the seriousness of my condition lightly. During that pregnancy I was also on Lopressor and towards the end he tried adding Nephedipine which didn't work. Around 32 wks as well, my pressure became more difficult to control but he kept playing around with the meds instead of inducing labor. I opted not to have an autopsy done but placental pathology revealed that several large infarcts had developed in the placenta due to pre-eclampsia and that is what they deemed the cause of death. My son weighed 4lbs 6 oz which again puzzles me because it seems like he was growing at a normal rate.

Two years have past and I am now considering trying to conceive again but obviously I have concerns. My first question to you is do placental infarcts developed as a result of hypertension/pre-eclampsia or was there most likely another cause of the infarcts? I wonder if I should have testing done to see if I have a clotting disorder but it puzzles me that I had no complications from that with my first pregnancy. I was able to locate my original MFS and I have met with him for a preconception consult and he doesn't think that any further testing is warranted but I will always wonder what the underlying cause of the infarcts was.

I would also like your opinion on my current drug regimen and how safe it will be during a pregnancy. I have been on Lopressor and Hydrochlorothiazide for the past 18 mos and my pressure is controlled the best it ever has been. My MFS tried switching me to Labetalol but I suffered every side effect listed and it did not control my pressure very well. My MFS is a little hesitant in keeping me on Hydrochlorothiazide but it is quite clear that I need the combination of Beta blocker and diuretic. What is your opinion on that combination of drugs during pregnancy.

I appreciate you donating your time to read my story and respond.

[expert@preeclampsia.org]

I will pass as a placental pathologist, except to say clots and infarcts are seen more frequently in hypertensive disorders, primarily preeclampsia, and may be related to relative hypoxia.. I doubt if there is any specificity here.

Concerning the case description: As usual one would like considerably more information, and thus again, as usual, my remarks are hypothetical and not related to this case specifically. First, sudden fetal loss, often unexplained, is an unfortunate occurrence and is associated with both diabetic and hypertensive gestations, one reason close monitoring, (including electronic evaluation of fetal heart rate patterns) is often commenced earlier in the pregnancy of these patients (though, metanalyses have not given good score cards to the use of fetal monitoring). The patient is correct that fetal growth here seems appropriate, especially since beta receptor blocking agents (lopressor here) are associated with smaller babies (labetalol is a combined alpha, beta blocker, thus less so), and one might have expected the extensive placental infarction also to be associated with growth restriction.

Now for the primary question: Non pregnant hypertensives are often classified as having volume dependent or independent hypertension, the former obviously better controlled with sodium restriction and diuretics. For this reason the NHBP working group gave physicians the option of continuing the use of a diuretic in chronic hypertensives who conceive when such therapy had been an important constituent of nonpregnant control. This patient’s statement of how good her control is now is an obvious hint that she has a volume component to her high blood pressure. Also, when chronic hypertensives loose control during pregnancy, adding a diuretic (carefully) is often more successful than other second line drugs, especially in diabetics, and personal experience has seen this approach prolong pregnancy to viability, especially in these diabetics with both high blood pressure and some edema. The thiazide diuretics are perhaps those with the largest history of pregnancy use as they were at one time prescribed in normal gestation to prevent preeclampsia, and thus their relative safety established.

I personally stop diuretics when the pregnancy starts given the normal decrease in blood pressure during both normal and most hypertensive pregnancies. However, if her physician chose to continue this, it would be a reasonable choice.