March 2014

Increasing Incidence of Neural Tube Defects?

Mon, 24 March 14 08:00

National Audit of Neural Tube Defects in Ireland in 2009 – 2011 Suggests Reversal of Previous Trend

Researchers at the HSE Health Intelligence Unit, associated hospitals and the UCD Centre for Human Reproduction at the Coombe Women & Infants University Hospital have conducted a detailed study of the incidence of neural tube defects within the Republic of Ireland for the period 2009 – 2011.

This comprehensive national audit over three years found that the incidence of neural tube defects (NTDs) increased slightly during the period studied, reversing the trend of the previous ten years.

Neural tube defects are major congenital anomalies which result in conditions such as anencephaly, spina bifida and encephalocoele. These conditions have a profound impact on the individual born with a NTD and their families, and represent a substantial economic cost to the health services.  Up to 70% of NTD are preventable through adequate peri-conceptional intake of folic acid by the mother-to-be.

The study published in the Journal of Public Health examined almost 226,000 births between 2009 and 2011 in all maternity hospitals nationally and paediatric hospitals which provide care for children with spina bifida in Ireland.  A total of 236 NTD’s were identified giving an incidence of 1.04/1,000 births, increasing from 0.92/1,000 in 2009 to 1.17/1,000 in 2011.  The three year trend is a reverse of the decline in incidence of NTD over the previous ten years.

The audit provides the most up-to-date information on the incidence of NTD in Ireland and reveals regional variation across the country, with the incidence of NTDs lower in Dublin than outside the capital. This variation across the country combined with the apparent reversal of the previous downward trend from 2009 could suggest that socio-economic factors are at play. 

Professor Michael Turner, UCD Professor of Obstetrics & Gynaecology at the UCD Centre for Human Reproduction, Coombe Womens & Infants University Hospital noted,

These findings are important because NTDs are one of the few preventable congenital anomalies and in Ireland the health burden for the child and the family is considerable.

The study also demonstrates that the rate of NTDs was significantly higher among Irish mothers compared with non-Irish mothers, confirming the historical higher risk which is in part related to methylenetetrahydrofolate reductase (MTHFR) polymorphism.

Given this higher risk of NTD and that many of these congenital anomalies are preventable with adequate pre-conceptional intake of folic acid, the report authors recommend an urgent review of public health policy on folic acid fortification, folic acid supplementation and pre-conceptional care in Ireland in the primary prevention of NTD.



Neural tube defects in the Republic of Ireland in 2009–11 [Link]

R. McDonnell1, V. Delany1,M.T. O’Mahony2, C.Mullaney3, B. Lee4,M.J. Turner4

1 Health Intelligence Unit, Health Service Executive, Dr Steevens Hospital, Dublin 8, Ireland
2 Department of Public Health, Health Service Executive, Block 8, St Finbar’s Hospital, Douglas Road, Cork, Ireland
3 Department of Public Health, Health Service Executive, Lacken, Dublin Road, Kilkenny, Ireland
4 UCD Centre for Human Reproduction, Coombe Women and Infants University Hospital, Cork Street, Dublin 8, Ireland