Preterm and low birth weight births among u.s. and foreign born mothers: Results from the los angeles mommy and baby (LAMB) project, 2010

Background: Los Angeles County (LAC) is an incredibly diverse population. Given the large immigrant population in LAC, and the importance of low birth weight (LBW) and preterm (PT) births, we aim to describe the birth outcomes and demographics of US and foreign born (FB) mothers in LAC.

Methods: We analyzed the 2010 LAMB data (N=6,593). LAMB is a population-based surveillance system designed to monitor self-reported experiences occurring before, during, and after pregnancy. Chi-square tests were used to assess differences between US and foreign born mothers and analyses were conducted using sampling weights to account for the complex sampling scheme.

Results: Forty-five percent of mothers were FB. Of the FB mothers, 24% had lived in the U.S. for <=10 years and 21% for >10 years. Nearly 13 percent of US born mothers were less than 20 years old compared to 4.7% of FB<=10yrs and 3.5% of FB>10yrs, p<0.0001. Among FB<=10yrs, 45.2% had less than a H.S. education compared to 26.7% for FB>10yrs and 14.3% of US born mothers, p<0.0001. Nine percent of US born mothers had LBW births compared to 5.5% of FB<=10yrs and 5.7% of FB>10yrs, p=0.002. Among US born mothers (10.6%) had preterm births compared to FB<=10yrs (8.2%) and FB>10yrs (8.9%), p=0.20.

Conclusion: Foreign born mothers were less likely to have LBW and preterm births, be <20yrs, and have a HS education when compared to US born mothers. Further research into the effect of time in the US on birth outcomes is warranted.