BIBLIOGRAPHIC INPUT SHEET TEMPORARY Patterns of mortality ...

Chapter X. Congenital Anomalies
205
Stein and Susser (1971), in a paper on the
preventability of Down's disease, recoinmended
specific preventive measures aimed
at reducing the frequency of this serious
condition. There are sound bases for education
of parents and for genetic counseling
to prevent the birth of a child with Down's
disease. The well-known relationship of the
frequency of this chromosomal abnormality
with increase in maternal age has been colroborated
availability by of this (liagnostic Investigation. tests for Also those the
availabilit ofte ian i sts1971) athe
risk of giving birth to a child with this congenital
anomaly should be mentioned among
the bases for prevention.
In nearly half of the 306 deaths from
Down's disease additional anomalies were
found (in 148 or 48.4 per centi. The most
frequent were those of the circulatory sys-
tern; in fact, 99 (32.4 per cent) of the infants
dying from this disease had circulatory
anomalies as well (Table 115). In four
projects half had circulatory anomalies, although
other anomalies were also found.
Unfortunately it was not always possible to
establish the specific type of anomaly of tile
circulatory system, although the diagnosis
of congenital heart disease was made on
clinical grounds. For this reason, the anom­
111ly most frequently mentioned was unspecified
womnad(tei Ssse, 171 ti congenital anomalies of
grat(746.9).
the heart
Interventricular septal defect
(746.9) wntfqentia Se eec
(746.3 was next in frequency. Several
anomalies of the upper digestive tract (cleft
palate and lip) and of the lower digestive
system with obstruction of the small intestine
were found in association with Down's
disease.
ANOMALIES OF CIRCULATORY SYSTEM
Anomalies of the circulatory system were
the most common. In fact, 963 or 33.5 per
cent of the 2,873 deceased infants with congenital
anomalies had at least one anomaly
of the circulatory system (Table 116 and
Figure 103). Usually these conditions were
serious and only 42 of these infants had only
a minor anomaly of the circulatory system.
The variation in mortality from these
conditions was great. The Bolivia project
had a rate of 53.2 per 100,000 live births,
or about one-sixth that in Sherbrooke
(300.5). Ten projects had rates of at least
200.0 per 100,000 live births, which indicated
considerable consistency in the frequency
of these serious defects of heart and
circulatory system.
The assignment of underlying cause in the
presence of various forms of anomalies of
heart and great vessels can be extremely
difficult and at times impossible. No special
rule was followed in the classification and
coding of these multiple anomalies, except
that the one stated in the record (clinical
or autopsy) and thought to be the most serious
was selected. Likewise, it was very
difficult at times to decide which of the other
anomalies of heart and vessels were contributors
to death, since it is known that
tinder certain circumstances, an anomaly
in this system can serve as compensatory
mechanism of another and even be lifesaving.
Another difficulty in assigning causative
value to an anomaly derives from the concept
of anomaly. In fact, some of these