Selected birth defects among males following the United States terrorist attacks of 11 September 2001.

BACKGROUND

The terrorist attacks of 11 September 2001 (hereafter referred to as 9/11) preceded an increase in male fetal deaths and reduced male live births among exposed gestational cohorts across several geographic locations in the United States, including California. We analyze whether the extreme stressor of 9/11 may have selected against frail males in utero by testing if the prevalence of male births with selected defects in California fell among cohorts exposed to the stressor during gestation.

METHODS

We used data from the California Birth Defects Monitoring Program from July 1985 to January 2004 (223 conception cohorts). We included six birth defects that as a group of phenotypes disproportionately affect males. We applied time-series methods and defined as "exposed to 9/11" the cohorts conceived in February, March, April, May, June, July, and August 2001.

RESULTS

Three of the seven monthly conception cohorts exposed to 9/11 in utero show lower than expected odds of live born males with the studied defects: February 2001 (odds ratio [OR] = 0.39; 95% confidence interval [CI], 0.21-0.71), May 2001 (OR = 0.36; 95% CI, 0.16-0.81), and August 2001 (OR = 0.51; 95% CI, 0.28-0.93).

CONCLUSION

The population-wide stressor of 9/11 precedes a reduction in the risk of live born males with selected birth defects. Our analysis contributes to the understanding of adaptation to stress among pregnant women exposed to large and unexpected ambient stressors. Results further support the notion that the prevalence of live born defects may reflect temporal variation in cohort selection in utero against frail males. Birth Defects Research 109:1277-1283, 2017. © 2017 Wiley Periodicals, Inc.