TY - JOUR A1 - Luo, Z.C. A1 - Wilkins, R. A1 - Kramer, M.S. T1 - Disparities in pregnancy outcomes according to marital and cohabitation status Y1 - 2004 JF - Obstetrics and Gynecology VL - 103 IS - 6 SP - 1300 EP - -1307 ER -