1 Department of Women's Health, University of Texas at Austin, 1301 W 38th St., Ste. 705, Austin, TX, 78705. Electronic address: lorie.harper@austin.utexas.edu.
2 Department of Biostatistics and Center for Women's Reproductive Health, University of Alabama at Birmingham, Birmingham, AL.
3 Department of Obstetrics and Gynecology and Center for Women's Reproductive Health, University of Alabama at Birmingham, Birmingham, AL.