CHICAGO – It’s clear that there’s a dose-dependent relationship between hypertension in pregnancy and poor outcomes, but, even so, treatment usually doesn’t begin until women hit 160/105 mm Hg or higher, according to Mark Santillan, MD, PhD, an assistant professor of obstetrics and gynecology – maternal fetal medicine at the University of Iowa, Iowa City.
M. Alexander Otto/MDedge News
Dr. Mark Santillan
That might soon change. The National Institutes of Health–funded CHAPS (Chronic Hypertension and Pregnancy) trial is testing whether earlier intervention improves outcomes, and it hopes to define proper treatment targets, which are uncertain at this point. Results are expected as soon as 2020.
What’s already changed is that the old treatment standby – methyldopa – has fallen out of favor for labetalol and nifedipine, which have been shown to work better. “Sometimes, we will throw on hydrochlorothiazide after we max out our beta- and calcium channel blockers,” Dr. Santillan said at the joint scientific sessions of the American Heart Association Council on Hypertension, AHA Council on Kidney in Cardiovascular Disease, and American Society of Hypertension (Cochrane Database Syst Rev. 2018 Oct 1;10:CD002252).
For severe hypertension, “most of the time we start off with IV hydralazine or IV labetalol” in the hospital. “You give a dose and check blood pressure in 10 or 20 minutes,” he said. If it hasn’t dropped, “give another dose until you reach your max dose.” When intravenous access is an issue, oral nifedipine is a good option (Obstet Gynecol. 2017 Apr;129[4]:e90-e95).
Delivery date is key; babies exposed to chronic hypertension are more likely to be stillborn. For hypertension without symptoms, delivery is at around 38 weeks. For mild preeclampsia – hypertension with only minor symptoms – it’s at 37 weeks.
In more severe cases – hypertension with pulmonary edema, renal insufficiency, and other problems – “the general gestalt is to stabilize and deliver when you can. See if you can get up to at least 34 weeks,” Dr. Santillan said. However, when women “have full-on HELLP syndrome [hemolysis, elevated liver enzymes, low platelet count], we often just deliver [immediately] because there’s not a lot of stabilization” that can be done. “We give magnesium after delivery to help decrease the risk of seizure,” he added.
Guidelines still use 140/90 mm Hg to define hypertension in pregnancy. When that level is reached, “you don’t need proteinuria anymore to diagnose preeclampsia. You need to have hypertension and something that looks like HELLP,” such as impaired liver function or neurologic symptoms, he said. Onset before 34 weeks portends more severe disease.
Daily baby aspirin 81 mg is known to help prevent preeclampsia, if only a little bit, so anyone with a history of preeclampsia or twin pregnancy, chronic hypertension, diabetes, renal disease, or autoimmune disease should automatically be put on aspirin prophylaxis. Women with two or more moderate risk factors – first pregnancy, obesity, preeclamptic family history, or aged 35 years or older – also should also get baby aspirin. Vitamin C, bed rest, and other preventative measures haven’t panned out in trials.
Investigators are looking for better predictors of preeclampsia; uterine artery blood flow is among the promising markers. However, it and other options are “expensive ventures” if you’re just going to end up in the same place, giving baby aspirin, Dr. Santillan said.
Dr. Santillan reported that he holds three patents; two on copeptin to predict preeclampsia and one on vasopressin receptor antagonists to treat it.