Book of Medical Disorders in Pregnancy - Tintash

Risk factors:
The risk of GDM increases with
increasing age, and high BMI before
pregnancy, Smoking doubles the risk of
gestational diabetes Increase in weight
between pregnancies, Short interval
between pregnancies, previous
unexplained stillbirth, previous
macrosomia and Family history of
GDM, also increases risk of developing
GDM.
Screening:
Because the condition may be
asymptomatic but have serious
consequences that can be reduced by
treatment the patient should be screened.
There is lack of consensus about who to
screen and the criteria for diagnosis.
Urine should be checked for glucose at
every antenatal visit and if it is present at
++, further investigation is required. The
World Health Organi-zation advice that
a 75 g oral glucose tolerance test
(OGTT) should be conducted if the
blood glucose exceeds 5.5 mmol/l at 2
hours or more after food, or exceeds 7
mmol/l within 2 hours of food. The
criteria recommended for diagnosis of
GDM are fasting venous plasma glucose
over 5.5 mmol/l or 2 hours after OGTT
over 9mmol/l. Screen-ing will detect
50% or more of all cases which means
that up to half will not be screened or
detected. Hence vigilance is required
during antenatal care, especially if there
is glycosuria.
Causes of diabetes: There is increased
level of hormones such as cortisol, and
human growth hormone during
pregnancy. These hormones are insulin
inhibitor. Hypertension coexists with
type II in about 40% at age 45 rising to
60% at age 75. 70% of type II patients
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die from cardio-vascular disease and at
least 60% of patients will require 2 or 3
antihypertensive agents to achieve tight
control.
Critical balance which is maintained
between these hormones during normal
health is upset during pregnancy.
The student will realize that insulin is
released from pancreatic islet cells in
response to hyperglycemia and hyper
aminoacidemia. The blood level of the
insulin is maintained by both synthesis
and transport of the hormone. In cases of
output failure, insulin dependent
diabetes results. The primary output
failure may be due to inherent deficiency
in pancreas. The secondary output
failure may be due to destruction of
islets, pancreatitis, and pancreatic
replacement with tomur,
hemochromatosis and exhaustion of
pancreas associated with increased
requirements. The pancreatic release of
insulin may be blocked by drugs such as
Thiazide and Epinephrine. The failure
may also be idiopathic or secondary to
known antagonist of insulin like cortisol,
epinephrine and human growth hormone
(HGH). The half life of insulin is 10
minutes.
Classification: There are number of
classi-fications reported in the literature.
These are shown below. Some of these
are based on history of the patient while
the other on laboratory findings and
clinical symptoms.
From obstetrical point, classification
presented by Pris-cilla Whites is
considered to be most useful and
practical.
A. Glucose tolerance test abnormal;
no symptoms, euglycemia