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

56
The apparent difference arose mainly from fl uctuations in numbers of antepartum deaths, as Table
2.2 shows. Despite the rising caesarean section rate, the numbers of women dying from postpartum
pulmonary embolism after caesarean section remains lower than in the early 1990s as thromboprophylaxis
becomes routine.
Table 2.2
Timing of deaths from pulmonary embolism; United Kingdom: 1985-2005.
Deaths after
miscarriage/
ectopic
Antepartum
deaths
Collapse before
delivery followed
by perimortem
caesarean section
Deaths
in labour
Death
after
caesarean
section
Deaths
after
vaginal
delivery
Not
known
Total
Direct
deaths
Late
deaths
1985-87 1 16 0 0 7 6 0 30 *
1988-90 3 10 0 0 8 3 0 24 4
1991-93 0 12 0 1 13 4 0 30 5
1994-96 3 15 0 0 15 10 3 46 2
1997-99 1 13 3 0 4 10 0 31 9
2000-02 3 4 1 1 9 7 0 25 1
2003-05 3 11 4 0 7 8 0 33 3
* Most Late deaths were not reported to enquiry in this triennium.
Cases counted in other Chapters
Pulmonary embolism also contributed to a few deaths from other causes which are counted and discussed
in other chapters. These include a case where it was the terminal event for a woman with advanced
cancer, discussed in Chapter 11, and two women who died of Indirect causes including Budd-Chiari
syndrome due to thrombosis obstructing the hepatic vein whose cases are counted in Chapter 10.
It must be remembered that not all cases of sudden collapse in the puerperium are due to pulmonary
embolism. For example, a woman who suffered a sudden fall in blood pressure two days after delivery was
initially investigated for pulmonary embolism. The actual cause of her death, haemorrhage from the internal
iliac vessels, was a rarity but intra-peritoneal haemorrhage should have been suspected from her pallor
and hypotension.
Incidence of antenatal pulmonary embolism
A prospective national case-control study of antenatal pulmonary embolism was undertaken through
the United Kingdom Obstetric Surveillance System (UKOSS) between February 2005 and August 2006.
UKOSS is discussed in fuller detail in the Introduction to this Report. Ninety-four incidents of antenatal
pulmonary emboli, including several deaths, were reported over the fi rst year, representing an estimated
incidence of 13.1 per 100,000 maternities with a 95% confi dence interval from 10.6 to 16.1. Seventy-three
of the women had one or more identifi able risk factors for thromboembolic disease. The main risk factors
for pulmonary embolism in this group were multiparity, with an adjusted odds ratio of 2.90 with a 95%
confi dence interval 1.37 to 6.13 and a Body Mass Index (BMI) over 30, with an adjusted odds ratio of 2.80
with a 95% confi dence interval from 1.12 to 7.02.