[Prenatal diagnostics of birth defects in the Czech Republic--a fifteen-year period].

AIM OF STUDY

An analysis of prenatal and postnatal incidences of selected birth defects and secondary prevention efficiency in the Czech Republic in 1994 - 2008 period.

TYPE OF STUDY

Retrospective epidemiological analysis of birth defects data from particular centers of clinical genetics and prenatal diagnostics (prenatal data) and from the Czech National Birth Defects Register database (birth data).

MATERIAL AND METHODS

Data from the National Birth Defects Register (Institute for Health Information and Statistics of the Czech Republic) were used along with data from particular centers of clinical genetics and prenatal diagnostics covering the whole area of the Czech and the 1994 - 2008 period. Total prenatal diagnostics efficiency and an efficiency of prenatal diagnostics of 5 selected defects (anencephaly, spina bifida, omphalocele, gastroschisis and Down syndrome) were studied.

RESULTS

In the period under study the number of prenatally diagnosed birth defects has increased. In 1994, the incidence of prenatally diagnosed (and selectively terminated) birth defects was 27.40 per 10 000 live births while in 2008 it was 73.26 per 10 000. In prenatally diagnosed but not terminated defects the corresponding numbers were 8.91 in 1994 and 32.87 in 2008. In last years, a quality change in prenatal birth defects screening has taken place in the Czech Republic. A first trimester screening with an increased efficiency not only for Down syndrome (DS) has been used more often implicating a wider application of chorionic villi sampling (CVS). An increased screening efficiency also made possible a relative decrease of invasive prenatal diagnostics procedures necessary to diagnose a single case of Down syndrome. When comparing CVS and amniocentesis from this particular point of view a higher CVS efficiency (about 12 CVS versus some 120 amniocenteses per 1 case of DS). Prenatal diagnostics efficiency has increased in all defects under study over the 1994 - 2008 period, being about 80% in DS almost 10% in anencephaly, 65 - 68% in omphalocele and gastroschisis and 80% in spina bifida in last years.

CONCLUSIONS

Chromosomal aberration (DS especially) are among the most frequent prenatally diagnosed birth defects, further being heart defects, neural tube defects (anencephaly, encephalocele, spina bifida), hydrocephalus, congenital skeletal system defects, abdominal wall defects (omphalocele, gastroschisis) and renal defects. In some defects, prenatal diagnostics has also significantly influenced their incidence in births (anencephaly, gastroschisis and DS e.g.).