The risk of birth defects after assisted reproduction.

Purpose: Aim of this study was to investigate the association between congenital malformations and type of conception (spontaneous or medically assisted).

Methods: This is a population based study using data from the regional data base of Lombardy, a Northern Italian Region with a population of about 10 million inhabitants. Included in the study were 277,043 neonates born in Lombardy during the study period 2010-2012.