The incidence of spina bifida in Sweden 1973-2003: the effect of prenatal diagnosis.

BACKGROUND

Many studies have been conducted on the accuracy of prenatal ultrasound diagnosis of foetal CNS-malformations. These studies were mostly hospital-based or, sometimes, multicentre studies. We present here a population-based study of the prenatal diagnosis of spina bifida in Sweden over a period of 31 years.

METHODS

We compared the number of newborns with spina bifida and the elective terminations because of the prenatal diagnosis of spina bifida for different periods.

RESULTS

The rate of spina bifida among newborns diminished gradually from 0.55 per 1000 to 0.29 per 1000 during the study period. In M county the rate of spina bifida at birth decreased very rapidly and from 1993 onwards was about half of that in the rest of the country.

CONCLUSION

There has been a decline in the rate of spina bifida at birth. This decline can be seen earlier in the southern part of the country, M county. The decline is probably, to a great extent, a consequence of prenatal ultrasound screening.