After a first birth, women’s earnings drop sharply. This well-documented “motherhood penalty” is attributed to changes in participation, hours, and wages. There is also evidence that new mothers cluster in firms with other new mothers, which suggests: (i) that there may be some unobserved “family-friendly” job characteristics at these organizations; and (ii) that part of the motherhood penalty may reflect new mothers trading off income for these desirable characteristics. We use a linkage of the Canadian Employer Employee Dynamics Database with data on workplace characteristics from the Workplace and Employment Survey to replicate the motherhood earnings penalty in Canada and analyze how job characteristics change over the course of a first birth. This linkage allows us to go beyond documenting a clustering of new mothers across organizations and to explore the characteristics of the organizations they move into including employee benefits (such as supplemental EI, dental, medical, life insurance) and work practices (flex time, control over work). We will discuss how we adapt established approaches to estimating a motherhood penalty to this linked workplace-tax data, as well as our findings on changes in benefits over the course of a first birth.