Mrs. L.C. was in the office the other day for her routine pregnancy check at 32 weeks gestation. This is her first pregnancy and it has been uneventful so far.
I was concerned to find her blood pressure to be slightly elevated, at 142/88. At the beginning of her pregnancy, her blood pressures had been in the 100 to 110 over 60 to 70 range. Two weeks ago, her blood pressure was 128 over 80. Towards the end of the visit, I rechecked her pressure and it was still high, at 138 over 90.
Her urine dipstick was negative for protein and negative for glucose. She had gained 5 pounds of weight in the last two weeks. She thought her fingers were a little puffy, but they looked OK to me. Her reflexes were normal.
I told her that I believed she was developing gestational hypertension. I based this on her persistent elevation of blood pressure above 140/90, but without any evidence of proteinuria. This is in contrast to pre-eclampsia, which also has persistent blood pressure elevation, but also includes significant proteinuria.
I told her that by itself, gestational hypertension was not dangerous and would not represent a threat to her or her pregnancy. The problem with gestational hypertension is that often, women with this will progress over time to pre-eclampsia, which does represent a threat to both the mother and her baby.
I recommended that she get more rest, specifically 1 hour every morning and 1 hour every afternoon resting in a horizontal position on her left side. I suggested she get an automatic home blood pressure cuff and begin recording her own blood pressures at least twice a day, once just after she gets up in the morning and another later in the day after she’s been up for a while. I also ordered some tests, including:
• CBC with platelets
• 24 hour urine collection for total protein
• Uric Acid
• Ultrasound for estimated fetal weight and amniotic fluid index
• Electronic fetal monitor Non-stress testing of the fetus
I gave her some warning signs, including headache, visual disturbances, right upper quadrant abdominal pain or epigastric pain, marked swelling, and decreased fetal movement. Then I arranged for her to return in 1 week so I could recheck her. I explained that although we normally wouldn’t begin weekly checks until the 36th week, that her blood pressure elevation made it necessary to more closely monitor her.
The big picture on her is that the pre-eclampsia/eclampsia syndrome is a continuum that starts relatively early in pregnancy with defective placentation. In the pre-eclampsia/eclampsia scenario, the cytotrophoblast, which is supposed to infiltrate the maternal spiral arteries all the way into the myometrium, only reaches the decidual portion of the spiral arteries. Because of this, the placenta fails to develop all of the normal large, low-resistance, high flow blood vessels and instead the vessels remain relatively narrow. The consequence is some degree of hypoperfusion of the placenta which may ultimately lead to at least focal placental ischemia.
The ischemic placenta releases a number of substances into the maternal circulation, among them Soluble fms–like tyrosine kinase 1 (sFlt-1 or sVEGFR-1) and soluble endoglin (sEng), and pro-inflammatory trophoblastic debris, which act on the maternal microvasculature to cause vasospasm and endothelial damage. All of the clinical symptoms of pre-eclampsia can be traced to this vasospasm and endothelial damage. Prior medical problems, like pre-existing hypertension, genetic factors, and immunologic factors may all be modifying factors, either to promote or protect against these injuries.
So she is demonstrating the earliest manefestations of this process, that began quite early in pregnancy, and is steadily worsening, although not yet to the dangerous stage.
So I have increased my surveillance of her, so that whenever she crosses the line into pre-eclampsia, I will know about it. I ordered the pre-eclampsia lab tests to first make sure she doesn’t already have pre-eclamsia, and second to serve as a baseline for further tests which she undoubtedly will have as her pregnancy progresses. I have started the NSTs and ultrasound scans because I know that she already has a placenta with some degree of malfunction…that’s why her BP is elevated in the first place, and that’s how she got gestational hypertension. While I’m not too worried about the fetus at this stage, things can change, sometimes rather rapidly, so I’d rather get started watching the fetus carefully now.