This paper describes the labor dynamics of U.S. women after they have had their first and subsequent children. We build on the child penalty literature by showing the heterogeneity of the size and pattern of labor force participation and earnings losses by demographic characteristics of mothers and the characteristics of their employers. The analysis uses longitudinal administrative earnings data from the Longitudinal Employer-Household Dynamics database combined with the Survey of Income and Program Participation survey data to identify women, their fertility timing, and employment. We find that women experience a large and persistent decrease in earnings and labor force participation after having their first child. The penalty grows over time, driven by the birth of subsequent children. Non-white mothers, unmarried mothers, and mothers with more education are more likely to return to work following the birth of their first child. Conditional on returning to the labor force, women who change employers earn more after the birth of their first child than women who return to their pre-birth employers. The probability of returning to the pre-birth employer and industry is heterogeneous over both the demographics of mothers and the characteristics of their employers.