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Similarly increased congenital anomaly rates after intrauterine insemination and IVF technologies: a retrospective cohort study.

BACKGROUND
While intrauterine insemination (IUI), a simple, inexpensive and non-invasive technique, is the most used assisted reproduction technology (ART) worldwide, the risk of major birth defects following IUI is paradoxically not well documented.


METHODS
Retrospective cohort study performed in Burgundy, France, over a 9-year period which consisted of the cross analysis of two prospective databases, the Burgundy perinatal network database and the database of the assisted conception units in Burgundy. A total of 1348 ART singletons [in vitro fertilization technologies (IVFT): n= 903; IUI: n= 445] matched with 4044 infants conceived naturally, 552 ART twins (IVFT: n= 362; IUI: n= 190) matched with 1656 twins who were conceived naturally. The major birth defects were categorized according to the European Surveillance of Congenital Anomalies classification EUROCAT.


RESULTS
Compared with naturally conceived singletons, singletons born after IUI and IVFT had a higher prevalence of major congenital malformations, with adjusted odd ratios (AOR) of 2.0 [95% confidence interval (CI) 1.0-3.8] and 2.0 (CI 1.3-3.1); 3.6 and 4.2% of infants born, respectively. All twins and unlike-sex twins born after IVFT but not IUI, have an increased prevalence of major birth defects compared with naturally conceived twins; AOR of 3.0 (CI 1.6-5.6) and 3.7 (CI 1.1-16.9), respectively. When comparing IUI with IVFT, no differences were observed for singletons (AOR 1.0; CI 0.4-2.2), all twins (AOR 0.4; CI 0.1-1.2) and unlike-sex twins (AOR 0.3; CI 0.1-4.5).


CONCLUSIONS
The risk of major birth defects in singletons conceived through IUI was increased over naturally conceived singletons. This risk was no different from that observed after IVFT.