When examining differences in wages between groups, an often studied and cited phenomena is the "gender wage gap:" the difference in earnings between men and women. The Bureau of Labor Statistics, for example, recently released a study which showed that in "2021, Kentucky women who were full-time wage and salary workers had median usual weekly earnings of $820, or 88.4 percent of the $928 median usual weekly earnings for their male counterparts." According to the Pew Research Center the differences between what men and women are paid haven't changed significantly over the last two decades. It is often also the case that these inequities can be exacerbated depending on educational attainment, race/ethnicity, and other key demographic factors. In this study, the Kentucky Longitudinal Data System (KLDS) was used to determine the influence of motherhood on the gender pay gap. Specifically, we looked at women in Kentucky who became first-time mothers in the year 2014 and tracked their wages until the first quarter of 2020 to investigate how many returned to work after becoming mothers and, among those who did, what happened to their wages during this period.

Do First-Time Kentucky Mothers Return to Work? 

There were approximately 29,000 women who became mothers in Kentucky in 2014 and had not had other children in the previous six years, over 66% (19,000) of whom were employed the year before giving birth. For the purposes of this study, we define these women as first-time mothers. It was found that 80% of first-time mothers who were previously employed were back to work after birth (and a six-month window). In comparison to all workers aged 19 to 44 in 2013, 86% were working one year later (with a six-month window in between to be comparable); a six-point difference. In fact, 73% of the first-time mothers in 2014 were working five years later compared to 75% of the population as a whole; a two-point difference.

As has been seen nationally, there were also differences in employment patterns between racial/ethnic groups in Kentucky. For example, 71% of new Black mothers in 2014 were working the year prior to birth, five percentage points higher than all first-time mothers in general. After having a child, 88% of Black mothers that were previously working then returned to work, two percentage points more than the working population as a whole aged 19 to 44.

 Of all workers aged 19 to 44 in 2013, 86% were working one year later.
First-time 2014 mothers returned to work at a rate six percentage points lower.

What Differences Exist Between Mothers, Fathers, and Non-Parents?

To further explore the impact of becoming a new mother on employment and earnings, new mothers in 2014 were compared to new fathers in 2014 and to men and women who worked in the same time periods as the new mothers in this study but did not have small children since 2007. Although these men and women could have older children, we refer to them as non-parents for simplicity.

Of the 29,000 first-time mothers in this study, over one-third of them received wages both the year before giving birth and for each of the five years following birth. To control for circumstances that may affect wages, each continuously working new mother was paired with individuals of the same race, highest degree earned by 2014, wages prior to birth, and age in 2014 who also worked the same six-year period. This means in the comparison, all groups started with a relatively level playing field with respect to these characteristics, each of which is typically correlated with wages. 

Our analysis shows that across the income range, median wage increases over five years were generally highest among new fathers (80%), followed (in order) by non-fathers (70%), non-mothers (57%), and lastly by new mothers (40%). This is referred to in other research as the fatherhood bonus and motherhood penalty. While this report does not imply causation, we dig deeper into cross-sections of populations to see if and when exceptions arise.

From 2013 to 2019, working first-time fathers' wages increased by 80%,
compared to a 40% increase in wages for first-time mothers.

Does Experience Matter?

Age can serve as a proxy for experience, where experience is very often correlated with wage. Wage trends observed in this study generally continue when looking for differences by age although notably, the so-called motherhood penalty is greatest among younger workers (19 to 24 year-olds) whereas the fatherhood bonus is most pronounced among 25 to 29 year-olds.

Wage differences between age groups were similar
to those seen between parental status and gender.

What About Starting Income Level?

We also examined prior wages in 2013 for all workers between the ages of 19 and 44 to determine if the difference is associated with the income level of the workers, as has been seen nationally. Specifically, we wanted to know whether the wage gap for new mothers was more prevalent among low wage workers as compared to those who earned higher wages. Prior income levels could influence new mothers' decision to return to work, especially if factoring financial need to work and availability or lack of affordable childcare.

When considering the prior wages of working mothers by income quartile, those in the bottom 25% had the most extreme discrepancy between the highest and lowest wage earners. Each of the male and female non-parents’ median wages were over fifty percent more than the first-time mothers’ wages. Additionally, the working first-time fathers did not have the highest median income five years after birth.

Those in the top 25% of wages in 2013 experienced the greatest divide between male and female non-parents. Working first-time fathers and those men without young children tended to have little difference in their wages over time, while working women without small children continued to out-earn working moms.

First-time mothers in the lowest quartile experienced the
largest motherhood penalty over any other income group.

This study is simply a beginning to understanding the impact that becoming a mother for the first time has on the employment and earnings trajectories of women in Kentucky. We will continue work to understand what other differences exist by asking questions about the impact of the industry of employment, such as education or healthcare, as well as ethnicity, race, or region. More recent various research has investigated the motherhood penalty and fatherhood bonus during the Covid-19 pandemic which we could address in the Commonwealth. Further research will include these topics to address the critical discussion around not only the gender gap, but more specifically gender gap among parents.

Data originated from the Kentucky Longitudinal Data System (KLDS)

Source of birth data: Office of Vital Statistics (OVS) - KDPH. Birth data from 2008 - 2014 is preliminary.

Source of wage data: Office of Unemployment Insurance