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RESEARCH ARTICLE
SA JOURNAL OF DIABETES & VASCULAR DISEASE
4
VOLUME 16 NUMBER 1 • JULY 2019
Hypertensive disorders of pregnancy: what the physician
needs to know
John Anthony, Albertino Damasceno, Dike Ojjii
Correspondence to: John Anthony
Division of Obstetrics and Gynaecology, Groote Schuur Hospital, University of
Cape Town, Cape Town, South Africa
e-mail:
john.anthony@uct.ac.zaAlbertino Damasceno
Department of Cardiology, Faculty of Medicine, Eduardo Mondlane University,
Maputo, Mozambique
Dike Ojjii
Department of Cardiology, University of Abuja, Abuja, Nigeria
Previously published in
Cardiovasc J Afr
2016;
27
: 104–110
S Afr J Diabetes Vasc Dis
2019;
16
: 4–10
Abstract
Hypertension developing during pregnancy may be caused
by a variety of different pathophysiological mechanisms. The
occurrence of proteinuric hypertension during the second half
ofpregnancyidentifiesagroupofwomenwhosehypertensive
disorder is most likely to be caused by the pregnancy itself
and for whom the risk of complications, including maternal
mortality, is highest. Physicians identifying patients with
hypertension in pregnancy need to discriminate between
pre-eclampsia and other forms of hypertensive disease. Pre-
eclamptic disease requires obstetric intervention before it
will resolve and it must be managed in a multidisciplinary
environment. The principles of diagnosis and management
of these different entities are outlined in this review.
Keywords:
hypertention disorders, pregnancy
Hypertension during pregnancy is widespread, representing the
most common medical complication of pregnancy and affecting
6–8% of gestations in the United States of America. Two hospital-
based studies in sub-Saharan Africa have put the prevalence of
this disorder at 11.5 and 26.5% of all deliveries, respectively.
1,2
There are four categories of hypertension in pregnancy, chronic
hypertension, gestational hypertension, pre-eclampsia, and pre-
eclampsia superimposed on chronic hypertension, as defined by
the National High Blood Pressure Education Program Working
Group in Pregnancy.
Hypertension during pregnancy is not only common but also
associated with a risk of morbidity and mortality.
3,4
The risk of
adverse outcomes during pregnancy is largely but not exclusively
confined to those pregnant women diagnosed to have pre-
eclampsia.
4,5
The separation of hypertension during pregnancy
into pre-eclampsia or non-pre-eclamptic disease is a foundational
consideration when determining the likely course of the disease,
the necessary management and the probable outcome.
3
Pre-eclampsia is uniquely manifest during pregnancy
and is associated with a pathophysiological phenotype that
encompasses placental disease, growth restriction of the foetus
and the development of severe but reversible hypertension during
pregnancy.
4,6,7
Chronic hypertension, regardless of the precise
diagnosis, is not specifically associated with placental vascular
disease or severe intra-uterine growth restriction and will not remit
after delivery.8 The necessary level of surveillance, hospitalisation
and the need for preterm delivery rests upon the distinction
between these hypertensive diagnoses.
9
In this review we discuss the different types of hypertension
during pregnancy, and the physician evaluation, including physical
examination and laboratory investigations of the hypertensive
pregnant patient.
Pre-eclampsia
Epidemiology
Pre-eclampsia affects one in 30 primigravid women and one in 60
women in their second or subsequent pregnancies.
10
Those who
have suffered from the condition before are more likely to develop
it in subsequent pregnancies (a one-in-seven risk) and women
with underlying co-morbidity are also more likely to develop this
complication of pregnancy. Specifically, women with chronic
hypertension have a 25% risk of developing superimposed pre-
eclampsia, and women with collagen vascular disease are also
more prone to develop pre-eclampsia.
8,9,11
There is also a hereditary
component, and obesity is strongly associated with the risk of
developing the condition.
12
Obstetric risk factors include an increasing risk of developing
pre-eclampsia related to multiple and even higher-order multiple
pregnancies. A large placenta, such as those seen in women with
trophoblastic disease or various kinds of foetal aneuploidy, are also
associated with an increased risk of developing pre-eclampsia. Other
risk factors that have been identified as leading to an increased
probability of pre-eclampsia developing during pregnancy include
antiphospholipid antibody syndrome, chronic hypertension, chronic
renal disease, a maternal age over 40 years, nulliparity, incidence
of pre-eclampsia in a previous pregnancy and pre-gestational
diabetes.
The highest incidence of pre-eclampsia is among women having
their first baby, whereas the greater prevalence of the disease is
in multiparous pregnant women. The disease is described as a
condition of primigravidity but it is also, to some extent, associated
with primipaternity.
10
Clinical phenotype
Pre-eclampsia is a syndrome characterised by the development of
hypertension and proteinuria in the latter part of pregnancy, which
then remits after delivery.
3
Pre-eclampsia is unlikely to be the cause
of hypertension or proteinuria developing before the 20th week of
pregnancy.
Hypertension is defined in different ways but the most widely
accepted definition is the sustained elevation of diastolic blood