Geographic and temporal analysis of folate-sensitive fetal malformations.
OBJECTIVE
To identify potential geographic and temporal clustering of folate-sensitive fetal malformations as a prelude to a targeted preconception curriculum in folic acid supplementation.


METHODS
Our comprehensive prenatal anomaly database was queried to select fetal malformations presumed to be sensitive to preconception folate insufficiency. Evidence of geographic clustering was evaluated by distribution of individual cases using zip codes of maternal residence. Potential temporal clustering of anomalies was sought by tabulating the frequency of each anomaly category during 5 consecutive 2-year intervals between 1992 and 2001.


RESULTS
Over a 10-year period, approximately 2000 fetal anomalies were identified, of which 400 (20%) were considered potentially folate sensitive. We found geographic clustering of ventral wall defects as well as obstructive uropathy by zip code analysis. Significant increases in the frequencies of cardiac defects (P <.001) and obstructive uropathy (P <.001) were noted during the epoch of this study. A moderate increase in anomaly frequency was also seen in the diagnostic subcategory of gastroschisis, in which 15 of 27 total gastroschisis cases occurred in 2000-2001.


CONCLUSIONS
Geographic clustering and temporal trends in anomaly rates were noted in certain folate-sensitive malformation categories. Identification of specific, high-incidence regions may provide an opportunity for targeted interventions designed to supplement the national folic acid campaign.
Gordon
Trent E J
TE
Department of Obstetrics and Gynecology,Evanston Northwestern Healthcare, Evanston, Illinois, USA.
Leeth
Elizabeth A
EA
Nowinski
Cynthia J
CJ
MacGregor
Scott N
SN
Kambich
Michelle
M
Silver
Richard K
RK
D016000:Cluster Analysis; D000013:Congenital Abnormalities / Q000453:epidemiology* / Q000209:etiology; D005260:Female; D005494:Folic Acid Deficiency / Q000150:complications*; D020139:Gastroschisis / Q000453:epidemiology; D006330:Heart Defects, Congenital / Q000453:epidemiology; D006801:Humans; D007087:Illinois / Q000453:epidemiology; D007231:Infant, Newborn; D009436:Neural Tube Defects / Q000453:epidemiology; D011247:Pregnancy; D014551:Urinary Tract / Q000002:abnormalities