what-when-how
In Depth Tutorials and Information
include some recommendations during pregnancy.
8
Management of congenital heart disease and pregnancy
need to be individualized for each patient. The goal of
management of patients with valvular disease is to opti-
mize cardiac output. The most common valvular issue
in congenital connective tissue disorders, including OI,
is aortic regurgitation.
7
As seen with mitral regurgita-
tion, the left ventricle compensates for diminished for-
ward low with increased left ventricular end-diastolic
volume. Thus, afterload reduction is recommended for
pregnant patients with left ventricular dysfunction or
dilation with special attention paid to the stress of deliv-
ery and fluid management at that time.
For patients who already have some cardiac compro-
mise, precautions should be taken. Echocardiograms
including ejection fractions should be obtained, ideally
prior to pregnancy. Patients with valvular dysfunction
and/or aortic root dilation will need management to
optimize cardiac output and if there is advanced dis-
ease consideration of operative correction prior to preg-
nancy.
8
However, the patient needs to be counseled that
mechanical valves and anticoagulation in pregnancy
have added complexities.
9
For those very rare patients
with ejection fractions less than 45%, counseling regard-
ing potential high maternal and fetal morbidity and
mortality needs to be discussed as a possible contrain-
dication to pregnancy.
8
Additionally, there are some changes in the shape
of the ribs probably due to ligamentous laxity. These
changes result in an increased cardiac silhouette on
X-ray studies, yet without true evidence for change in
cardiothoracic ratios. These changes need to be taken
into consideration when making the diagnosis of car-
diomegaly on plain films. Thus, in a patient with OI if
there is concern for cardiac dysfunction, an echocardio-
gram, not plain film radiography, is appropriate.
10
consumption.
11
This results from increased require-
ments of the fetus, placenta and maternal organs.
Because of increased oxygen consumption and a low-
ering of maternal oxygen reserves, pregnant women
are more susceptible to the aspects of apnea. In healthy
pregnant women, 70% of patients complain of dys-
pnea.
13
Thus it is a very common complaint and close
attention needs to be paid to a patient complaining of
worsening or new onset dyspnea.
In severe forms of OI associated with chest wall
deformities, particularly sternal deformities and kypho-
scoliosis, there can be reduced forced vital capacity
and abnormal ventilation parameters.
14
There is a lack
of precise outcomes in women with OI and severe
kyphoscoliosis with mild to severe restrictive lung dis-
ease. Beyond OI, restrictive lung disease has not been
well studied in pregnancy. Previous studies noted a
higher risk of cardiopulmonary failure with restric-
tive pulmonary function,
15
but other reports suggest
better outcomes. A more recent series on women with
kyphoscoliosis due to varying etiologies suggested
that in their series of 22 patients and 34 gestations (six
with severe restriction and four with mild to moder-
ate dysfunction) there were no adverse cardiopulmo-
nary events and outcomes were good.
16
Therefore, if
there is any patient with severe progressive deforming
OI, or those with known respiratory compromise, pul-
monary function testing prior to pregnancy is advised
and multidisciplinary teams with expertise in pulmon-
ology, cardiology and critical care should be assembled
to manage the patient. Similarly to cardiovascular com-
plications, affected individuals who have pre-existing
respiratory compromise should be evaluated and coun-
seled prior to pregnancy. Those with vital capacities of
1.5 L or less (50% of predicted) would be considered
having severe pulmonary compromise and patients
should be counseled regarding potential for poor out-
come, though some favorable outcomes have been
reported. Values under 1.25 L may identify patients
at particular risk, though each patient needs to be
individualized.
17
PULMONARY FUNCTION
Changes in the chest wall configuration and the dia-
phragm produce changes in lung volumes. Elevation of
the diaphragm decreases the pulmonary resting volume
and thus reduces lung capacity and functional residual
capacity.
11
In addition, increasing levels of progesterone
derived from the placenta produce a state of chronic
hyperventilation, with a 30 to 50% increase in tidal vol-
ume by 8 weeks' gestation.
12
This results in increased
alveolar oxygen and decreased arterial carbon dioxide
from normal levels. The lower carbon dioxide levels
help drive a favorable CO
2
gradient from the fetus to
the mother.
As pregnancy advances and there is increased ven-
tilation, there is also an increase in oxygen uptake
SKELETON
Calcium Metabolism
Historically, pregnancy was thought to be a state of
“physiologic hyperparathyroidism” with maternal skel-
etal calcium loss used to supply the fetus, and preg-
nancy could contribute to long-term maternal bone loss.
However, most fetal calcium needs are met through
a series of physiologic changes in calcium metabolism
without any maternal effect.
18
These maternal adap-
tions allow fetuses to accumulate overall about 21g of
