ABSTRACT
Introduction Hypertension is one of the commonest pre-existing medical conditions encountered in women of childbearing age. Chronic or pre-existing hypertension complicates 3-5% of pregnancies, although this figure may rise with the trend for women to postpone childbirth into their 30s and 40s.1 Pre-existing hypertension has implications for pregnancy outcome and the woman’s long-term health. Some drugs used to treat hypertension are teratogenic or ill advised in pregnancy and alterations to medication regimens may be required pre-conception. There are three types of hypertension in pregnancy:
pre-existing hypertension, gestational or pregnancyinduced hypertension (PIH), and pre-eclampsia. This chapter focuses on pre-existing hypertension, although women with previous PIH or pre-eclampsia also require pre-pregnancy counselling regarding recurrence risks. Women with pre-existing hypertension may have
essential hypertension, often in association with a family history of hypertension, or they may have hypertension that is secondary to renal, cardiac or endocrine disease or associated with co-morbidities such as obesity, diabetes or polycystic ovarian syndrome. One of the important roles of periconceptional med-
icine in women with hypertension is to establish the underlying cause of the hypertension, and specifically to exclude secondary causes. These may be serious medical conditions, associated with adverse pregnancy outcomes and serious maternal morbidity such as reflux nephropathy, phaeochromocytoma or aortic coarctation, or medical conditions that themselves influence fertility, such as renal failure or Cushing’s syndrome. The hypertension may be curable or ameliorated by treatment of the underlying cause such as renal artery stenosis. If the woman has been previously appropriately and
thoroughly investigated to exclude secondary causes of hypertension, then it is not necessary to repeat these investigations. However, hypertension in any young person should not be attributed to essential (idiopathic) hypertension before secondary causes such as renal and cardiac disease, and rarely endocrine disorders
have been excluded. Hypertension that is newly diagnosed, that is not associated with a family history, that is discovered in a particularly young woman (e.g. age <30 years) or that has not been previously investigated warrants thorough investigation prior to pregnancy. The secondary causes of hypertension are shown in Table 6.1. Of these the commonest secondary cause encountered is renal disease, including, particularly in women of child-bearing age, reflux nephropathy, glomerulonephritis and renal artery stenosis. Women presenting with hypertension should be
examined for clues to a possible secondary cause. This should include examination of the femoral pulses (looking for radiofemoral delay, suggesting coarctation of the aorta) and a search for renal bruits (possible renal artery stenosis) and features of Cushing’s syndrome. Women with hypertension should also have urinalysis performed to identify proteinuria or haematuria that may suggest underlying renal disease, or glycosuria suggesting diabetes. A simple screen with serum creatinine and urea (to
exclude renal impairment), and electrolytes (to exclude hypokalaemia, which may suggest Conn’s syndrome) should be performed. Liver function tests and a serum calcium are required to calculate a corrected calcium to exclude hypercalcaemia as a cause of hypertesion. Urinary catecholamines should be
Table 6.1 Secondary causes of hypertension.
