50 / 72
CARDIOVASCULAR JOURNAL OF AFRICA • Volume 27, No 2, March/April 2016
104
AFRICA
Hypertensive disorders of pregnancy: what the physician
needs to know
John Anthony, Albertino Damasceno, Dike Ojjii
Abstract
Hypertension developing during pregnancy may be caused
by a variety of different pathophysiological mechanisms. The
occurrence of proteinuric hypertension during the second
half of pregnancy identifies a group of women whose hyper-
tensive 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
Submitted 14/1/16, accepted 14/4/16
Cardiovasc J Afr
2016;
27
: 104–110
www.cvja.co.zaDOI: 10.5830/CVJA-2016-051
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.
Division of Obstetrics and Gynaecology, Groote Schuur
Hospital, University of Cape Town, Cape Town, South Africa
John Anthony, MB, ChB, FCOG, MPhil,
john.anthony@uct.ac.zaDepartment of Cardiology, Faculty of Medicine, Eduardo
Mondlane University, Maputo, Mozambique
Albertino Damasceno, MD, PhD, FESC
Department of Cardiology, University of Abuja, Abuja, Nigeria
Dike Ojjii, MD, PhD, FESC