Working Group Report, 2000). At Parkland Hospital we initi ate treatment with antihypertensive agents for blood pressures of 150/100 mm Hg or higher. Our preferred regimens include mono therapy with a 3-blocking drug such as labetalol or a calcium-channel blocking agent such as amlodipine. For women in the first half of pregnancy, therapy with a thiazide diuretic seems reasonable. This is especially true in black women, in whom there is a high prevalence of salt-sensitive chronic hypertension.
It is controversial whether or not women who present early in pregnancy and who are already taking antihypertensive drugs should continue to take these (Rezk, 2016). According to the American College of Obstetricians and Gynecologists (2013) and the Society for Maternal-Fetal Medicine (2015), for women with mild to moderate hypertension, it is reasonable to discontinue medications during the irst trimester and to restart them if blood pressures approach the severe range. Our practice at Parkland Hospital is to continue treatment if the woman is already taking drugs when she presents for prenatal care. Exceptions are discontinuation of angiotensin-converting enzyme inhibitors and receptor blockers.
Some women will have persistently worrisome hypertension despite usual therapy (Samuel, 2011; Sibai, 1990a). In these women, primary attention is given to the likelihood of pregnancy-aggravated hypertension, with or without superimposed preeclampsia. Other possibilities include inaccurate blood-pressure measurements, suboptimal treatment, and antagonizing substances such as chronic ingestion of nonsteroidal antiinlammatory drugs (NSAIDs) (Moser, 2006; Sowers, 2005).
As discussed, the frequency of superimposed preeclampsia for women with chronic hypertension varies depending on the study population and hypertension severity (Ankumah, 2014). Importantly, in 40 to 50 percent of chronically hypertensive women, superimposed preeclampsia develops before 37 weeks (Chappell, 2008; Harper, 2016). This proportion is even higher in women who required hypertension treatment during pregnancy (Morgan, 20 16a).
The diagnosis may be diicult to make, especially in women with hypertension who have underlying renal disease with chronic proteinuria (Cunningham, 1990; Morgan, 2016b). As discussed in Chapter 40 (p. 712), conditions that support the diagnosis of superimposed preeclampsia include worsening hypertension, new-onset proteinuria, neurological symptoms such as severe headaches and visual disturbances, generalized edema, oliguria, and certainly, convulsions or pulmonary edema. Making the diagnosis based on worsening proteinuria in women with baseline proteinuria is problematic. Supporting laboratory abnormalities are rising serum creatinine or hepatic transaminase levels, thrombocytopenia, or any of the facets of
HELLP (hemolysis, �levated liver enzyme levels, low 2latelet count) syndrome. For women with chronic hypertension and superimposed preeclampsia with severe features, magnesium sulfate for maternal neuroprophylaxis is recommended (Ameri can College of Obstetricians and Gynecologists, 2013). Severe hypertension is treated as described in Chapter 40 (p. 738).
Some pregnant women with chronic hypertension have worsening hypertension with no other findings of superim posed preeclampsia. This is most commonly encountered near the end of the second trimester. In the absence of other supporting criteria for superimposed preeclampsia, this likely represents the higher end of the normal blood-pressure curve shown in Figure 50-1. In such women, if preeclampsia can be confidently excluded, it is reasonable to begin or to increase the dose of antihypertensive therapy.