While the number of women serving in Congress is increasing, there's been a drop in the number of female GOP legislators in recent years while Democrats are seeing greater participation.

Driving the news: Rep. Susan Brooks (R-Ind.) announced her retirement from the House on Friday. She and Rep. Jackie Walorski are the first Republican women to represent Indiana in Congress since 1959.

Brooks worked heavily to recruit GOP women to run for office, and her resignation worries Republican legislators about 2020 efforts.

Her resignation could send a stark message at a time when the Republican party is trying to recruit more women to run for federal and local offices.

The big picture: Democrats took back control of the House in the 2018 midterms, and credit is owed to the women who ran for office.

These female legislators, both freshmen and senior, have been bringing topics such as sexual harassment, paid maternity leave and equal pay to the forefront of Congressional debates.

Republicans could be alienating more modern voters because of the lack of gender diversity among candidates, and recent attacks on abortion rights.

By the numbers: There's been a steady increase in the number of female GOP senators. The 8 currently in office is an all-time high, per Brookings Institution.