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

64
2 Thrombosis and thromboembolism
There were was only one case of sub-standard care, where a woman died after developing ovarian
hyperstimulation syndrome (OHSS) during assisted conception treatment. She had had superovulation
followed by embryo transfer but no thromboprophylaxis. Thromboprophylaxis should always be given in
OHSS. It is concerning that two deaths in this Chapter and one in Chapter 6 - Early pregnancy deaths,
resulted from in vitro fertilisation procedures involving ovarian stimulation to produce large numbers of
mature follicles.
The characteristic clinical picture of all of the women who died from central venous thrombosis was of
a relatively short history of headache followed, sometimes very quickly, by neurological signs such as
clouding of consciousness or confusion. One woman was an asylum seeker who did not speak English and
psychiatric referral was considered but the correct diagnosis was quickly made. No woman was diagnosed
at the stage of headache alone. A severe headache of new onset can be an indication for neuro-imaging
in, or after pregnancy even in the absence of focal signs.
There is a striking similarity between cerebral and pulmonary thrombosis with regard to risk factors,
including obesity. It is to be hoped that increasing application of thromboprophylaxis among at-risk women
will reduce deaths from both forms of thromboembolism.
Sub-standard care overall
Care was judged to be sub-standard in only one case of cerebral vein thrombosis, but present in twothirds
(22 of the 33) cases of pulmonary embolism. The main reasons were inadequate risk assessment
in early pregnancy compounded by a failure to recognise or act on risk factors and a failure to appreciate
the signifi cance of signs and symptoms in the light of known risk factors. There were also failures to initiate
treatment promptly or in adequate dosages. Giving thromboprophylaxis to morbidly obese women in doses
recommended by current guidelines was not judged to be sub-standard care provided that the higher
recommended dose was given to women to women with body weight over 90kg.
There was poor risk assessment in early pregnancy (or before pregnancy in the case of morbidly obese
women), and failure to recognise the signifi cance of symptoms such as leg pain and breathlessness.
Better awareness of symptoms among professionals and women themselves could reduce the number of
deaths from this condition. New guidelines are needed on thromboprophylaxis for morbidly obese women,
especially those with a BMI over 40. Current guidelines recommend that the prophylactic and therapeutic
doses of low molecular weight heparin depend on the woman’s weight. This was followed sometimes but
not in all cases and a specifi c guideline on morbid obesity is needed.
Conclusions
With increasing rates of obesity, more and further air travel, a rise in the average age at childbearing
and caesarean section rates of around 23%, it is pleasing that the number of maternal deaths from
thromboembolism has hardly changed since 1985-87. This is almost certainly due to increasing vigilance
among obstetricians and midwives and the careful application of thromboprophylaxis protocols. The fall in
deaths from postpartum embolism after caesarean section shows the effectiveness of this strategy.
The same strategy should now be applied to prevent deaths in early pregnancy and postpartum deaths
after vaginal delivery. Thromboembolism is not a “bolt from the blue”. Risk factors were identifi ed in 27 of
the 41 women whose deaths are counted in this Chapter. Of the ten women who died in the fi rst trimester