Table 2.

Description of follow‐up method for livebirths by registry from registries contributing to the International Clearinghouse for Birth Defects Surveillance and Research

Country‐registry	Follow‐up until discharge from the maternity hospital	Follow‐up by a clinician or registry staff	Linkage with death certificates	Maximum follow‐up period reported in study
Argentina‐RENAC	Yes	Yes	No	1‐6 d
Colombia‐Bogotá	Yes	Yes	No	1 d
Colombia‐Cali	Yes	Yes	No	No mortality reported for live births
South America‐ECLAMC	Yes	Yes	No	28 d‐11 mo
Czech Republic	No	No	Yes	≥5 y
France‐Paris	Yes	Yes	No	7‐27 d
Germany‐Saxony Anhalt	Yes	Yesb	No	1‐4 y
Italy‐Lombardy	No	No	Yes, 2003 up to 2015	1‐4 y
Italy‐Tuscany	No	No	Yes, 1992 up to 2015	28 d‐11 mo
Malta‐MCAR	Yesa	Yes	Yesd	1‐4 y
Netherlands‐Northern	Yes	Yes	No	≥5 y
Slovak Republic	Yes	No	No	1‐6 d
Spain‐ECEMC	Yes	No	No	1‐6 d
Sweden	No	No	Yes, 1974 up to April 2016	≥5 y
UK‐Wales	Yes	No	Yes, to GP system, till 18 y	≥5 y
Ukraine‐OMNI‐Net	Yes	Yes	No	1‐4 y
Mexico‐Nuevo León	Yes	No	No	1‐6 d
Mexico‐RYVEMCE	Yes	No	No	1‐6 d
USA‐Arkansas	Yes	No	Yes, 1993 up to 2015	≥5 y
USA‐Atlanta	Yes	No	Yes, 1979 up to 2008	≥5 y
USA‐Texas	Yes	No	Yes, 1996 up to 2013	≥5 y
USA‐Utah	Yes	No	Yes, until age 2 y	≥5 y
Iran‐TROCA	Yes	Yesc	No	1‐6 d
Israel‐SMC	Yes	No	Yes, 2000 up to 2014	1‐4 y

Abbreviations: ECEMC, Registry of the Spanish Collaborative Study of Congenital Malformations; ECLAMC, Latin American Collaborative Study of Congenital Malformations; GP, General Practitioner; MCAR, Malta Congenital Anomalies Registry; OMNI‐Net, Ukraine Birth Defects Prevention Program; RENAC, National Network of Congenital Anomalies of Argentina; RYVEMCE, Mexican Registry and Epidemiological Surveillance of External Congenital Malformations; SMC, Soroka Medical Center; TROCA, Tabriz Registry of Congenital Anomalies; UK, United Kingdom; USA = United States of America.

Follow‐up method for livebirths:

^aBabies are followed up until discharge, and their hospital files are again seen at 1 y of age, linkage with mortality data continues indefinitely.

^bUntil 18 years.

^cChildren in university hospital(s).

^dContinuous linkage with mortality register, for this study, data have linkage up to 2015.