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RESEARCH ARTICLE
SA JOURNAL OF DIABETES & VASCULAR DISEASE
4
VOLUME 17 NUMBER 1 • JULY 2020
Prevalence of gestational diabetes mellitus in urban women
in Blantyre, Malawi: a cross sectional study evaluating
diagnostic criteria and traditional risk factors
TAMARA J PHIRI, MARIANNE KASIYA, THERESA J ALLAIN
Correspondence to: Tamara J Phiri
Queen Elizabeth Central Hospital, Blantyre, Malawi
e-mail:
tamaraphiri@gmail.comMarianne Kasiya, Theresa J Allain
Department of Internal Medicine, College of Medicine, University of
Malawi, Blantyre, Malawi
S Afr J Diabetes Vasc Dis
2020;
17
: 4–9
Abstract
Background:
Gestational diabetes mellitus (GDM) is
associated with maternal and neonatal complications. The
application of appropriate diagnostic criteria is essential.
There is a paucity of GDM prevalence data for African
countries, including Malawi.
Objectives:
This study aimed to establish the prevalence
of GDM in Blantyre, Malawi and assess the implications of
applying different cut-off points for diagnosis as defined
by WHO criteria and the recently established International
Association of Diabetes in Pregnancy Study Group (IADPSG)
criteria. It evaluated the relevance of internationally
defined risk factors for GDM and compared the risk factors
and prevalence between women accessing antenatal care
in private hospitals to those accessing antenatal care at
government hospitals. Patients at private hospitals are
generally of a higher socio-economic status, have better
access to care and are more likely to have a sedentary
lifestyle and Westernised diet.
Methods:
In this cross-sectional study, 2 274 consecutive
women presenting at five antenatal clinic sites in Blantyre
were screened for GDM, employing a random blood glucose
(RBG) test. Of these, 250 women were randomly selected for
an oral glucose tolerance test (OGTT). Logistic regression was
used to quantify the association between various exposure
variables and prevalence of GDM. Characteristics of patients
attending government and private antenatal clinics were
compared.
Results:
The study population was predominantly urban,
with a mean age of 25 years (range 14–43) with 66% being
in the third trimester. The mean RBG level was 5.1 mmol/l
(range 2.4–10.6) and overall prevalence of GDM based on
the OGTT was 1.6 and 24% using the WHO and IADPSG
criteria, respectively. GDM, diagnosed using WHO criteria,
was associated with older maternal age, high parity, and
attendance at government antenatal clinics but not with
mid upper-arm circumference, a positive family history of
diabetes mellitus (DM) or previous poor neonatal outcome.
There was no correlation between RBG level and GDM
diagnosed on the OGGT.
Conclusions:
The prevalence of GDM in Blantyre using WHO
criteria was low in the predominantly young population that
was screened. A much higher proportion had GDM based
on the IADPSG criteria and these may warrant long-term
follow up. GDM was not associated with some previously
described risk factors for GDM, suggesting a different risk-
factor profile compared to the high-income countries.
Keywords:
gestational diabetes mellitus, diabetes mellitus, non-
communicable diseases, pregnancy, sub-Saharan Africa, Malawi
Background
Gestational diabetes mellitus (GDM) is defined as any degree
of glucose intolerance with onset or first recognition during
pregnancy.
1
It is associated with an increased risk of pre-eclampsia,
macrosomia and risk of the mother developing type 2 diabetes
mellitus after pregnancy. Infants born to mothers with GDM
are at an increased risk of birth trauma and neonatal metabolic
complications, including hypoglycaemia, hypocalcaemia and hyper-
bilirubinaemia.
2,3
Risk factors for GDM in developed countries
include advanced maternal age, obesity and a family history of
diabetes mellitus (DM).
4
Few studies have been done in Africa on the prevalence of GDM.
A 2013 systematic review on the prevalence of GDM in Africa
found data for only six of the 54 African countries.
5
The review
included 14 studies and estimated the average prevalence of GDM
in Africa at 5% (range 0–14). While some studies in the review
screened women with risk factors for GDM only, others screened
all women regardless of risk factors. The study populations were
predominantly rural and GDM was associated with macrosomia,
maternal age over 30 years and prior history of diabetes mellitus.
Comparisons between the African studies are limited by
heterogeneity of the study populations, small sample sizes and
variable diagnostic criteria used. In seven African studies over the
past three decades, using the WHO criteria, the prevalence was
reported as 3.8% in South Africa (1989),
6
0% in Tanzania (1990),
7
11% in Nigeria (1997),
8
3.7% in Ethiopia (1997),
9
1.7% in Nigeria,
10
3.8% in South Africa (2007),
11
and 14% in Nigeria (2012).
12
Among studies using WHO criteria, however, some used the 1985
diagnostic criteria while others used the 1999 diagnostic criteria.
In Malawi, the nationwide WHO STEPwise Approach to
Surveillance (STEPS) survey in 2009 found that 5.6% of adult
Malawians had DM, the majority of which was undiagnosed.
13
There are no studies on the prevalence of GDM in Malawi.
There has been a universal lack of consensus on screening
and diagnosis of GDM with regard to the impact of screening on