Income and earnings penalties for motherhood: Estimates for women in the United Kingdom using a separate synthetic control method. 

European Sociological Review, Volume 37, Issue 5, October 2021, Pages 834-848, https: //doi.org/10.1093/esr/jcab014

Commentary

This study used data from the British Household Panel Survey to estimate the maternal penalty on own income and total household income, focusing on women who became mothers between 1995 and 2005.

Adopting a different approach than previously employed in studies of the maternal penalty, we follow Hernán and Robins, setting up the data as a "target trial" and analyzing it using IndividualSyntheticControl methods based on the SyntheticControl approach. 

Abadie, Diamond, and Hainmueller's There is considerable variation in the effect of motherhood on earnings for women in the UK. However, we show that the median penalty is about a 45 percent reduction in medium- to long-term earnings compared to what a woman would have earned if she had remained childless.

While motherhood does not affect women's household income on average, it has been shown to have a substantial negative impact on some households.

Focusing on both individual and household penalties provides a more complete picture of the consequences of the distribution of motherhood than has been previously available.