Background

The New Hampshire Birth Conditions Program (NHBCP) is a population-based, active case ascertainment surveillance system that monitors the occurrence of 45 birth defects across the state. A 2008 law requires a new opt-out procedure whereby legal guardians can choose whether or not to have identifiable information retained in the NHBCP database. The purpose of this study was to determine the effects of implementing this opt-out legislation on data collection and surveillance of birth defects by the NHBCP.

Methods

Using surveillance data collected following implementation of the opt out legislation for the period January 1, 2007, through December 31, 2009, 2 opt-out groups were created: the identifiable information retained (IIR) group, consisting of families who did not choose to opt out, and the de-identified information retained group (DIIR), consisting of those who either chose to opt out or were treated as opt-out birth defect cases because their opt-out package was undeliverable. Descriptive statistics were calculated for each group, and chi-square or Fisher’s exact tests were used to compare the proportion of select sociodemographic and medical characteristics between the 2 opt-out groups.

Results

Of 776 infants, 120 (15.5%) fell into the DIIR group. Differences were observed by race/ethnicity (among non-Hispanic whites, 15% were in the DIIR group and among Hispanics, 33% were in the DIIR group; p=0.01) and by maternal age (among women 30–34 years of age, 11% were in the DIIR group, and among those 25 years of age or younger, 22% were in the DIIR group; p=0.05). Birth outcomes, payer source, county of residence, and common birth defect diagnoses did not differ between the opt-out groups.

Conclusion

This study demonstrated that there were significant differences in race/ethnicity and maternal age between parents who had de-identified information included in the NHBCP compared with those who did not choose to opt out. Although the surveillance of birth defects is not affected, the opportunities for certain types of research will be limited.