The impact of paid family leave in the United States on birth outcomes and mortality in the first year of life.

OBJECTIVE

To evaluate the effect of paid family leave in California on statewide rates of preterm birth, low birthweight, postneonatal mortality, and overall infant mortality.

DATA SOURCES

Live birth and death certificates from all in-hospital deliveries occurring in California (state exposed to the family leave policy) and two unexposed states (Missouri and Pennsylvania) from 1999 to 2008 (n = 6 164 203).

STUDY DESIGN

We used a difference-in-differences approach to compare rates of infant health outcomes before and after implementation of the 2004 policy in California with rates in two states without paid family leave policies. Prespecified stratified analyses examined whether policy response differed by maternal characteristics. Conditional regression models using comparisons matched on a mother's likelihood of living in California in the pre-family leave period were then employed as sensitivity analyses to confirm our findings.

DATA COLLECTION/EXTRACTION METHODS: Probabilistic methods were used to match live birth records to maternal and newborn hospital records. Only singleton births were included. Dyads were excluded if the infant gestational age was <23 weeks or greater than 44 weeks or if the birthweight was an outlier.

PRINCIPAL FINDINGS

Compared to the unexposed states, adjusted postneonatal mortality rates decreased by 12 percent in California after 2004 (aOR 0.88, 95% CI 0.80-0.97). There were no significant effects on the other outcomes. There were no differences in the effect by race/ethnicity or insurance status except for increased odds of low birthweight among privately insured women in California after 2004. Point estimates in the propensity score-matched sensitivity models were similar to the results of the fully adjusted models for all four outcomes, but confidence intervals crossed one.

CONCLUSIONS

Implementation of paid family leave policies in California was associated with a 12 percent reduction in postneonatal mortality after adjusting for maternal and neonatal factors.