Saving Mothers' Lives: - Public Health Agency for Northern Ireland

an estimated incidence of 1.1 per 100,000 maternities with a 95% confi dence interval of 0.4 to 2.4 and
with no case fatalities. 5 Three of the cases were attributed to congenital heart disease, one to chronic
thromboembolism, one to sleep apnoea and one to primary pulmonary hypertension. Five cases were
known prior to pregnancy and only one diagnosed during pregnancy.
Acquired heart disease
Myocardial infarction and ischaemic heart disease
Sixteen women died from either myocardial infarction and/or ischaemic heart disease. Of the twelve who
died from myocardial infarction, eight deaths were due to ischaemic heart disease, in two the underlying
cause was undetermined, one was due to coronary artery dissection, a recognised complication of
pregnancy, and one due to a coronary embolism. Where the site of the coronary atheroma was identifi ed
at autopsy, it involved the left anterior descending coronary artery in four cases, the right coronary artery in
one further case and triple vessel disease in another.
For three of the four other women whose deaths were attributed to ischaemic heart disease no myocardial
infarction was seen at autopsy. The other woman died of left ventricular failure due to ischaemic heart
disease. In all, ischaemic heart disease was responsible for the deaths of twelve women. This represents
a four fold increase in deaths from ischaemic heart disease compared to the last triennium, probably
refl ecting the impact life style factors such as increasing maternal age, obesity and smoking have on the
health of women of childbearing age.
The women who died
All of the women who died from ischaemic heart disease had identifi able risk factors. Six were aged 35 or
over and the age range was 27 to 40 with a median of 35 years. Six were morbidly obese with a BMI of 35
or more, of whom four had a BMI over 40. All but one were parous, two had known hypertension, seven
were smokers, one had a family history and two had type 2 diabetes. Three women were Asian and the
others were White. Three of these women were poor attenders for antenatal care.
The Late deaths of four further women who died after childbirth from myocardial infarction were also
considered by the assessors, three were due to coronary artery dissection and one was due to ischaemic
heart disease, although there were undoubtedly more cases which remained unreported as the women will
have died many months after ceasing contact with the maternity services. The one woman whose death
was assessed and classifi ed as a Late death from an myocardial infarction due to ischaemic heart disease
fi tted the classic picture of women at risk in that she was parous, obese, aged over 40 and had type 2
diabetes.
There were four postpartum deaths from myocardial infarction due to coronary artery dissection although
three of these are counted as Late. Two involved the left anterior descending coronary artery, one the
right coronary artery, and one both arteries. Although rare in general, coronary artery dissection is a not
uncommon cause of coronary artery occlusion related to pregnancy.
The UKOSS study of acute myocardial infarction in pregnancy, undertaken from August 2005 to July
2006, identifi ed four confi rmed non-fatal cases, giving an estimated incidence of 0.6 cases per 100,000
maternities (95% confi dence interval 0.02, 1.4). 5
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