2.10. Congenital malformations

Congenital abnormalities are morphogenesis errors determined only partly by genetic factors (25% of cases). Exposure of the mother and foetus to known teratogenic factors (infectious, physical, chemical and illnesses of the mother) is responsible for approximately 9-10% of defects, whereas for 65% the aetiology is unknown, and may be due to complex interactions between the genes and the environment.

When considered individually, congenital malformations are usually rare, however their overall prevalence at birth (diagnosed within the first week of life) is approximately 2% (1 case in 50). Their frequency varies from one case in every 150-200 births for congenital heart diseases considered together to one case every 11,000-12,000 births for gastroschisis. Taken together they are numerically significant, involving about 5-6% of children in their first year of life.

During the 2004-2007 period some 7,894 cases of congenital malformations were reported out of 512,867 births monitored (live births + still births), with a total prevalence of 153.62 (per 10,000).

The congenital defects observed refer to 5,628 live births, 2,217 abortions and 49 still births (still births include both babies born dead and foetal death subsequent to the 20th week of gestation.

Overall, chromosome abnormalities (1,327) represent approximately 17% of the whole caseload, with a total prevalence of 25.82 per 10,000 inhabitants. The most frequent chromosome disorder is Down’s syndrome (total prevalence 16.31).

An aggregated analysis of the 14 subgroups of chromosome defects defined by EUROCAT indicates that cardiovascular malformations are the most frequent type (total prevalence 44.95), followed by chromosome abnormalities (total prevalence 25.82), limb defects (total prevalence 22.09), defects of the urinary system (total prevalence 18.35), nervous system (total prevalence 16.81) and genitalia (total prevalence 15.76). All the other groups have total prevalences lower than 10 per 10,000.

Despite the persistence of a lack of knowledge on the aetiopathogenesis of multifactorial congenital malformations, a strategy for primary prevention involves a number of evidence-based points:

• the promotion of appropriate folic acid supplementation in women starting/hoping to start a pregnancy;
• the promotion of anti-rubeola vaccination and prevention of toxoplasmosis during pregnancy;
• the correct use of medicinal products in fertile women, with particular regard to anti-epileptic, cancer and endocrine treatments and awareness amongst medical staff of the possible alternative therapies;
• the promotion of health, responsible eating and lifestyles, dedicating particular attention to the prevention of cigarette smoking, excessive drinking, diabetes and obesity;
• the protection of occupational conditions, in particularly in the presence of exposure to toxic substances (e.g. intensive farming).