Cork University Maternity Hospital (CUMH) has for the first time given clinical details of three maternal deaths* that occurred in mothers under its care last year - the highest number of annual deaths of mothers since the hospital opened.

irishhealth.com has learned that one of the 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.

In two of the cases, it is reported that the babies survived.

Last year saw the highest number of maternal deaths recorded by CUMH since its opening in 2006. The latest annual report from CUMH says prior to last year, there had only been two previous maternal deaths at the hospital since it opened.

The report says while all maternal deaths are devastating, the immediacy of those occurring during pregnancy is particularly devastating for the staff.

Prior to 2012, the two previous maternal mortalities at CUMH were from from pulmonary embolism 12 weeks after delivery, while the second was from alcohol/drug overuse at six weeks.

Nationally, the total number of maternal deaths in 2012 is not yet known, as the maternity units that produce annual reports with details of their clinical results have not yet published their reports.

However, it is known from media reports that in addition to the Cork deaths, two maternal deaths also occurred at Dublin's Coombe Hospital in the autumn of 2012, which means there were at least five maternal deaths nationally last year.

The maternal deaths occurring in Cork were first revealed by the Irish Examiner newspaper late last year.

The maternity units, as well as the recently-established Maternal Death Inquiry System (MDE Ireland) use wider criteria than that used in official Central Statistics Office (CSO) figures for classifying what constitutes a maternal death.

Under CSO criteria, the maternal death rate in Ireland is only around four per 100,000, whereas using the wider maternity unit/MDE Ireland criteria, the rate is around eight per 100,000.

The CSO has recorded only one maternal death occurring nationally last year, believed to be the death of Savita Halappanavar at University Hospital Galway. However, using the more generally accepted wider criteria for recording mothers who die around the time of childbirth, the final figure for 2012 could be at least five times that number.

In 2011, the Dublin maternity hospitals alone reported six maternal deaths, while CSO figures, which rely on official registration of deaths, recorded only two maternal deaths nationally.

Even taking this into account, our maternal death rate is still regarded as low by international standards.

However, there is a information deficit when it comes to providing details on maternal deaths and maternal morbidity in Ireland.

Not all maternity units publish annual reports, while the MDE Ireland stats, while they give some details about maternal deaths, do not give figures on how many deaths relating to childbirth there are each year or where the deaths occurred. Neither does the HSE publish such figures.

The public must therefore rely on those maternity units that produce annual reports and sometimes on media report to get a clearer picture of the incidence and causes of maternal deaths in Ireland.

The latest MDE Ireland stats, published last year, show that that 25 mothers who attended maternity units with their pregnancies died between 2009 and 2011. However, these statistics do not give a yearly breakdown of deaths or where they occurred.

The safety body HIQA, in its recent review of the Savita Halappanavar case, noted that eight of the country's 19 maternity units do not produce any form of annual clinical report detailing their clinical results.

HIQA said on examination of the eight published reports from the maternity units outside Dublin, they were found to varied significantly in style, format and degree of detail.

"For example, some of the reports contained commentary of individual cases of maternal morbidity and mortality while others provided statistical summary data only," HIQA noted.

The safety body also called on the HSE to publish an implement a suite of national performance measures for maternity services with a clear focus on patient outcomes. This, it said, would allow action to be taken on clinical results of hospitals where variance exists locally.

CUMH is one of the country's busiest maternity units, with 8,563 babies delivered last year. The annual report says while the average number of babies delivered each day is 23, on some days it can be double that number.

The CUMH annual report for 2012 notes that its maternal mortality rate for the period since it opened in 2006 is nine per 100,000, similar to the MDE Ireland national maternal mortality rate statistics.

*Maternal deaths at CUMH 2012 detailed in annual report:

1. A 38-year old woman with high body mass index (BMI) and a history of type 2 diabetes and chronic hypertension. At 37.5 weeks gestation treated for chest infection and pulmonary embolism. Sudden maternal collapse and cardiac arrest followed while an inpatient. Emergency caesarean performed, patient successfully resuscitated but patient died nine days later in intensive care. Coroner's postmortem found cause of death to be cardiac arrest due to cardiomyopathy associated with morbid obesity. A live infant was born, was transferred to neonatal unit and was discharged home well with father.

2. A 23-year old known to have sickle cell disease. Attended for a planned admission for blood transfusion at 14 weeks. Five days later attended hospital in acute sickle cell crisis. Fetal demise confirmed on ultrasound after cardiac arrest. The woman was resuscitated but died two days later.

3. A 34-four year old, known smoker. Uneventful pregnancy and induced or post-maturity, Live male infant delivered at 41 weeks. Discharged home well. Two weeks later sudden maternal collapse at home. Transferred to local general hospital but death confirmed shortly after arrival. Coroner's postmortem found cause of death to be coronary artery dissection (this is where a tear develops in the coronary artery).