Cardiac Consultation for Infants of Diabetic Mothers
Division of Pediatric Cardiology
MUSC
September 27, 2006
Background
Infants of diabetic mothers have an increased risk of cardiac
malformations. The magnitude of the risk is similar to that of parents with prior
offspring affected by cardiac malformations – somewhere between 2 and 5 times
the background rate of cardiac malformations. The risk for malformation is linked
most significantly to glycemic control in the first 6 weeks of pregnancy. These
data are well known to the high risk obstetrical community, who generally follow
these patients very closely and typically thoroughly and accurately evaluate for
fetal malformations, including cardiac malformations, by fetal ultrasonography.
Hypertrophic cardiomyopathy (HCM) is an additional concern in the IDM.
Many studies document differences in the hearts of the IDM in mass and
function, in some examples as early as 12 weeks gestation. These changes are
believed to be the result of the hyperinsulinemic-hyperglycemic environment of
the heart that is accompanied by increased IGF-1 signaling and increased
cardiac output demands. HCM in IDMs can therefore be regarded as the end of a
spectrum of cardiac responses to the physiologic environment of a diabetic
pregnancy. The generally observed outcome of HCM in IDM is complete
resolution by 6 months of age, and medical intervention is only infrequently
needed. HCM in the IDM does not have an association with arrhythmias, and
sudden arrhythmic death in IDMs with HCM and no other signs or symptoms of
HCM has not been described.
The prevalence of symptomatically affected IDMs with HCM is not well
known but does not appear to be high. The incidence of echocardiographicallyidentified asymptomatic and self-limited abnormalities in the IDM population is
also not well defined, but in anecdotal experience as well as literature reports,
subclinical ‘abnormalities’ are commonly identified that do not usually change the
management or outcome of the infant.
Suggested Guidelines
On the basis of these findings, we suggest the following guidelines for cardiac
evaluation in an infant of a diabetic mother.
1. All infants born to mothers with diabetes should undergo a thorough clinical
cardiac evaluation after birth by the pediatric or neonatal healthcare provider,
with special attention paid to the four-limb blood pressures and the second
heart sound.
2. The mother’s chart should be reviewed and the results of any fetal
ultrasonography and fetal echocardiography should be noted.
3. A cardiology consultation should be requested if there is a symptom or sign
referable to the heart – tachypnea, a loud (3/6) systolic murmur, a diastolic
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murmur, central cyanosis, low oxygen saturation on pulse oximetry, or a low
PaO2 on an arterial blood gas.
An infant with a cardiac murmur who is hemodynamically stable and has no
respiratory problems should be followed with periodic clinical examination
during the hospital stay. If a cardiology evaluation is thought necessary in
such infants, it is best performed closer to the time of hospital discharge, to
allow for the disappearance of transient clinical findings from transitional
circulation. An urgent or ‘stat’ evaluation should not be requested in such
patients.
If there are clinical findings that raise the possibility of a cardiac disease but
the infant is hemodynamically normal, and the findings of fetal
ultrasonography or fetal echocardiography rule out a serious cardiac
malformation, it is often appropriate to send the patient home and refer to the
cardiology clinic on an elective basis.
If a higher than normal level of vigilance is desired for infants of diabetic
mothers, routine pulse oximetry prior to discharge should be considered as a
possible back-up screen to physical examination for the question of
cardiovascular malformation.
Mandated early (1 week) follow-up can serve to increase surveillance for
evolution of murmurs or tachypnea indicating a symptomatic degree of HCM.