There are over 214 million international migrants worldwide, half of whom are women, and all of them assigned by the receiving country to an immigration class. Immigration classes are associated with certain health risks and regulatory restrictions related to eligibility for health care. Prior to this study, reports of international migrant post-birth health had not been compared between immigration classes, with the exception of our earlier, smaller study in which we found asylum-seekers to be at greatest risk for health concerns. In order to determine whether refugee or asylum-seeking women or their infants experience a greater number or a different distribution of professionally-identified health concerns after birth than immigrant or Canadian-born women, we recruited 1127 migrant (and in Canada <5 years) women-infant pairs, defined by immigration class (refugee, asylum-seeker, immigrant, or Canadian-born). Between February 2006 and May 2009, we followed them from childbirth (in one of eleven birthing centres in Montreal or Toronto) to four months and found that at one week postpartum, asylum-seeking and immigrant women had greater rates of professionally-identified health concerns than Canadian-born women; and at four months, all three migrant groups had greater rates of professionally-identified concerns. Further, international migrants were at greater risk of not having these concerns addressed by the Canadian health care system. The current study supports our earlier findings and highlights the need for case-finding and services for international migrant women, particularly for psychosocial difficulties. Policy and program mechanisms to address migrants' needs would best be developed within the various immigration classes. Copyright © 2012 Elsevier Ltd. All rights reserved.