Chronic hypertension augments the risk two-to threefold for premature placental separation. he general obstetrical population risk is 1 in 200 to 300 pregnancies, and this rises to 1 in 60 to 120 pregnancies in women with chronic hypertension (Ankumah, 2014; Cruz, 2011; Magee, 2015). he abruption risk is elevated further if the woman smokes. Most abruptions are in women with worsening gestational hypertension or superimposed preeclampsia. The abruption risk is highest with severe hypertension, and Vigil-De Gracia and colleagues (2004) reported it to be 8.4 percent. From medical record data from the Norwegian Birth Registry, folic acid and/or multivitamin supplements slightly lowered the abruption incidence in women with chronic hypertension (Nilsen, 2008).
Rates of almost all adverse perinatal outcomes are greater in women with chronic hypertension than in nonafected controls. As expected, for the entire group of hypertensive women, those who developed preeclampsia have substantially higher adverse outcome rates compared with those without preeclampsia. As shown in Figure 50-3, adverse outcome rates rise incrementally with rising blood pressures. Evidence also supports that chronic hypertension-treated or untreated-is associated with show little or no benefit. Low-dose aspirin has been evaluated 55
FIGURE 50-3 Frequency of selected adverse maternal and perinaLa! uuLcomes by blood stratification in women with mild chronic hypertension. SGA = small for gestational age. (Data Ankumah,o2014.) most frequently (Mol, 2016; Sta, 2015). In the MFMU Network study by Caritis (1998) cited above, the incidence ofsuperimposed preeclampsia, fetal-growth restriction, or both is similar in women given low-dose aspirin or placebo. Using the same database, Moore and associates (2015) found that early administration of low-dose aspirin « 17 weeks' gestation) resulted in a significant 41-percent lower frequency of superimposed preeclampsia in chronically hypertensive women-18 versus 31 percent. Duley (2007) and Meads (2008) and their colleagues performed systematic reviews and noted that low-dose aspirin was beneicial in some high-risk women. Moderate beneits were also found from a metaanalysis by Askie and coworkers (2007). In a secondary analysis, Poon and associates (2017) noted that aspirin was inefective to reduce the incidence ofpreterm preeclampsia.
he U.S. Preventive Services Task Force recommends treatment with low-dose aspirin for chronically hypertensive congenital anomalies. Bateman and coworkers (2015) from the Medicaid Analytic Extract cited earlier found an elevated risk for severe congenital malformations-especially cardiac defects. Moreover, severe hypertension and fetal esophageal atresia or stenosis have been associated (Binhidy, 2011; Van Gelder, 2015).