A Relative Rise in Blood Pressure From 18 to 30 Weeks’ Gestation Is Associated With Reduced Fetal Growth and Lower Gestational Age at Delivery
Much Ado About Nothing?
See related article, pp 36–44
Hypertensive disorders in pregnancy include gestational hypertension, chronic hypertension, and preeclampsia. Collectively, these disorders complicate 6% to 20% of all pregnancies.1 The rates of hypertensive disorders of pregnancy (HDP) will continue to increase because of the trend regarding advanced maternal age and increased body mass index at time of pregnancy.1 These disorders, particularly preeclampsia, are more commonly associated with increased rates of small for gestational age (SGA) infants, preterm birth (PTB), and low-birth-weight infants. PTB is defined as delivery at <37 weeks’ gestation, and it can be spontaneous because of either preterm labor or preterm rupture of membranes (spontaneous PTB) or indicated PTB as a result of maternal or fetal reasons.2 SGA is defined as birth weight at <10th percentile, and low birth weight is defined as a birth weight of <2500 g.
There is some evidence that preeclampsia and pregnancies complicated by SGA have similar risk factors, suggesting that they may share similar pathophysiology. For example, women with prior history of preeclampsia are at increased risk for SGA and preeclampsia in subsequent pregnancies, and women who are born SGA are at increased risk of preeclampsia and SGA in subsequent pregnancies.3 In addition, women with prior history of preeclampsia are at increased risk for PTB and SGA even when they have subsequent normotensive gestation.4 However, the cause of SGA and PTB is multifactorial, and only SGA and PTB related to placental insufficiency probably share …