Hypertensive disorders of pregnancy are the second most common cause of maternal death in developed countries (after embolism), accounting for 15% of all maternal deaths.
Effects of pregnancy on maternal cardiovascular system
- Blood volume increases 800 mL by 12 weeks (1.5 L in twins).
- Blood pressure (BP) decreases in early pregnancy (due primarily to a decrease in systemic vascular resistance secondary to progesterone), nadirs in mid-pregnancy, and returns to baseline by term.
Classification
1 Chronic hypertension
- Definition. Hypertension before pregnancy. The diagnosis should also be entertained in women with BP ≥140/90 mmHg before 20 weeks’ gestation.
- Complications. Such pregnancies are at increased risk of superimposed pre-eclampsia, intrauterine fetal growth restriction (IUGR), placental abruption, and stillbirth.
- Management. Continue antihypertensive medications with the exception of angiotensin-converting enzyme (ACE) inhibitors. These drugs have been associated with progressive and irreversible renal injury and possibly other structural anomalies in the fetus. Diuretic therapy is generally discouraged.
- Fetal testing (serial ultrasound examinations for fetal growth with or without fetal non-stress testing) should be initiated after 32 weeks’ gestation. Delivery should be achieved by 40 weeks.
2 Chronic hypertension with superimposed pre-eclampsia (see Preeclampsia below)
3 Gestational hypertension
- Also known as gestational non-proteinuric hypertension.
- Diagnosis. Persistent elevation of BP ≥140/90 mmHg in the third trimester without evidence of pre-eclampsia. It is a diagnosis of exclusion that is best made retrospectively.
- Etiology.
Stay updated, free articles. Join our Telegram channel
Full access? Get Clinical Tree
