Dublin's Coombe Hospital has for the first time revealed the causes of two maternal deaths that occurred within 48 hours of each other in women in its care in September 2012.

The hospital's clinical report for 2012, which has just been released, said the deaths, which occurred shortly after delivery, were due to Sudden Adult Death Syndrome (SADS) and Amniotic Fluid Embolism.

However, the Coombe has removed further details of the circumstances surrounding the deaths from the published report. This was done to protect patient confidentiality, a hospital spokesperson told irishhealth.com

The report also reveals that a third maternal death occurred in a pregnant woman under the care of the Coombe in 2012, with the cause of death given as suicide.

This means that the Coombe in 2012 recorded its highest number of maternal deaths so far this century. Only five mothers in total died in its care between 2000 and 2011.

At the end of 2012, Health Minister James Reilly told the Dail that internal reviews into the two deaths at the Coombe within 48 hours of each other found that they were due to 'different natural causes' ' and were unrelated to specific practices in each case.

Dr Reilly described the timing of these maternal deaths so close to each other as 'bizarre coincidences'. Twin babies born to one of the mothers survived and featured in media reports at the time, while it is understood that the infant born to the second woman also survived.

As maternal deaths are still quite rare in Ireland, it is regarded as highly unusual for two mothers to die within such a short space of time in a maternity hospital.

Both cases were referred to the Dublin City Coroner.

One of the causes of death given, Sudden Adult Death Syndrome (SADS), often occurs as a result of a previously hidden heart condition. Amniotic fluid embolism is described as a rare obstetric emergency where amniotic fluid, fetal cells, hair, or other debris enter the mother's bloodstream via the placental bed of the uterus and trigger an allergic reaction.

The two deaths at the Coombe following caesareans occurred under two different medical teams and in two different theatres.

The HSE recently confirmed to irishhealth.com that 10 maternal deaths, both directly and indirectly related to pregnancy and childbirth, occurred in Ireland in 2012, compared to 12 in 2011.

While the HSE did not provide a breakdown of where the deaths occurred, it is now known, following publication of the clinical reports from all the units concerned, that the hospital locations were:

Cork University Maternity Hospital (CUMH)- 3 deaths.

Coombe- 3 deaths

Rotunda- 2 deaths

Holles Street - one death

University Hospital Galway - one death (Savita Halappanavar).

CUMH has confirmed that of its three deaths in 2012, two were in women with pre-existing conditions, while one happened unexpectedly following a normal delivery. One of the Cork maternal deaths was due to cardiac arrest associated with obesity and diabetes, another occurred following cardiac arrest associated with the mother's sickle cell disease, while the third death was due to a coronary event following a seemingly normal pregnancy and birth.

Savita Halappanavar's death, outlined in UHG's 2012 clinical report, was due to severe sepsis and septic shock following which she died after serious multi-organ failure.

According to details published in the Rotunda's latest clinical report, both its 2012 maternal deaths were indirect. In one case the woman was found dead at the cliffs in Howth, Co. Dublin, while in the other case the patient died having after a collapse secondary to cardiac arrest three months after the birth.

Further summary information about the circumstances leading to the Holles Street death was not provided in the hospital's recently-published 2012 report.

Holles Street is to date the only maternity unit where a death occurred in 2012 that has not even revealed the reported cause of death, let alone a summary of the circumstances, in its annual clinical report.

It is regarded as unusual for a hospital not to provide summary details of the circumstances surrounding maternal deaths, or at least the cause of death, when they occur.

Holles Street said no details were given as the coroner investigation process was ongoing at the time the report was compiled. However, other hospitals often give details of maternal deaths while coroner's inquests are awaited.

There were six maternal deaths at the three Dublin maternity hospitals in 2012, the same number as in 2011.

Direct maternal deaths are defined as being due to obstetric complications as a result of interventions, omissions or incorrect treatment, while indirect deaths include where women may have pre-existing medical conditions or conditions developing during pregnancy which were aggravated by the physiological effects of the pregnancy.

Figures on maternal deaths in maternity units in 2013 will not be available until later this year.