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CARDIOVASCULAR JOURNAL OF AFRICA • Volume 31, No 3, May/June 2020
136
AFRICA
The effect of beta-blockers on foetal birth weight in
pregnancies in women with structural heart disease:
a prospective cohort study
Johann Baard, Feriel Azibani, Ayesha Osman, Wentzel Dowling, Brian Rayner, Karen Sliwa
Abstract
Objective:
To examine whether treatment with beta-blockers
(BBs) in pregnant women with structural heart disease (SHD)
resulted in a decrease in foetal birth weight (FBW) in a South
African cohort.
Methods:
This was a prospective cohort study conducted in
a tertiary-level hospital in Cape Town from 2010 to 2016. Of
the 178 pregnant women with SHD, 24.2% received BBs for
a minimum of two weeks. Adverse foetal outcomes and mean
FBW were compared between the BB groups and subgroups
(congenital, valvular, cardiomyopathy and other). Adverse
foetal outcome was defined as: low birth weight (LBW)
<
2 500 g, Apgar score
<
7, premature birth (
<
37 weeks) and
small for gestational age (SGA).
Results:
BB exposure during pregnancy was found to be
associated with a non-significant increased FBW (2 912 vs
2 807 g,
p
=
0.347). A significant decrease (
p
=
0.009) was
noted in FBW for valvular SHD pregnancies using BBs,
while a significant increase (
p
=
0.049) was observed for the
same outcome in the cardiomyopathy subgroup using BBs.
A significant increase was observed for SGA (
p
=
0.010) and
LBW (
p
=
0.003) pregnancies within the valvular subgroup
when exposed to BBs.
Conclusion:
BB use in pregnant women with SHD in a
South African cohort showed no association with a decrease
in FBW or an increase in adverse foetal outcomes when
compared to non-BB usage.
Keywords:
beta-blockers, pregnancy, women, heart disease, foetal
outcome
Submitted 29/11/18, accepted 6/10/19
Published online 13/11/19
Cardiovasc J Afr
2020;
31
: 136–141
www.cvja.co.zaDOI: 10.5830/CVJA-2019-061
Increasingly, pregnancies worldwide are complicated in women
with pre-existing structural heart disease (SHD).
1
Maternal
congenital heart disease (CHD) dominates in high-income
countries,
2
while rheumatic valvular disease (RVD) represents the
most frequent SHD in pregnancies in low- to medium-income
countries.
1
Pregnancies in women with SHD exhibit higher-
than-average maternal mortality rates,
3
necessitating increased
monitoring and medication use during the antenatal period.
The most commonly observed maternal complications during
pregnancies affected by SHD are congestive heart failure and
arrhythmias.
4-6
SHD also increases the rate of adverse foetal outcomes
[preterm delivery, intra-uterine growth retardation (IUGR)
and low birth weight (LBW)], with the strongest predictor of
these outcomes being maternal cyanosis and reduced cardiac
output.
7-11
These adverse events set in motion a cascade of
possible foetal neuro- and bronchopulmonary developmental
abnormalities,
12,13
resulting in increased healthcare costs
14
and
maladaptive programming in adult life.
15,16
Foetal outcomes, in part, are determined by maternal
cardiovascular adaptation during pregnancy. Inadequate
adaptation due to SHD leads to reduced utero-placental
perfusion, resulting in impaired foetal growth and nutrition.
7
This association is complicated by the use of beta-blockers (BBs)
in pregnancies with SHD, as these drugs have been previously
associated with small-for-gestational-age (SGA) infants and
LBW,
17-19
although some studies show contradictory results.
20-22
BBs have also been associated with neonatal hypoglycaemia and
bradycardia in the third trimester, with no increase in congenital
defects shown.
21,23
Studies investigating the effect of BBs on SGA and LBW
have focused more on hypertensive pregnancies
19,24-26
than studies
regarding SHD pregnancies.
27,28
In addition to the effect on the
foetus, BBs can also cause maternal bronchoconstriction, fatigue
and sleep disturbances, which further signifies the importance
of an interdisciplinary decision regarding the use of BBs
in pregnancies with SHD.
23
In this prospective study among
patients recruited from a tertiary hospital in South Africa, we
aimed to investigate the effect of treatment with oral BBs in
woman with SHD on the foetal birth weight (FBW).
Hatter Institute for Cardiovascular Research in Africa,
Department of Medicine, Faculty of Health Sciences,
University of Cape Town, South Africa
Johann Baard, MB ChB, MSc
Feriel Azibani, PhD
Wentzel Dowling, MB ChB
Karen Sliwa, MD, PhD,
Karen.Sliwa-Hahnle@uct.ac.zaDepartment of Obstetrics and Gynaecology, Groote Schuur
Hospital, University of Cape Town, South Africa
Ayesha Osman, MB ChB, FCOG
Division of Hypertension and Nephrology, Groote Schuur
Hospital, University of Cape Town, South Africa
Brian Rayner, MB ChB, MMed, FCP, PhD
Department of Cardiology, Groote Schuur Hospital,
University of Cape Town, South Africa
Johann Baard, MB ChB, MSc
Karen Sliwa, MD, PhD
Mary McKillop Institute for Health Research, ACU,
Melbourne, Australia
Karen Sliwa, MD, PhD