March is Women’s History Month, a time to recognize and celebrate great strides in women’s fight for equality, but also a reminder of the challenges that remain. One thing is clear: They were once barred from the polling booth, but over the last 100 years women have grown into arguably the largest, most influential group of voters in America. And with that influence comes the opportunity for continued progress.

A few short years ago women disproportionately faced skyrocketing health care costs. One Department of Health and Human Services study found that women, especially those of reproductive age, were more vulnerable to high health care costs because they required more regular contact with health care providers.

Even among the insured population, significant gender inequities existed. Women were more likely to be under-insured, with gaps in coverage that left them medically or financially at risk, because insurers could deny coverage for certain “pre-existing” conditions and procedures. Thanks to the Affordable Care Act (ACA), not only are maternity services mandated for all insurance plans in the Health Insurance Marketplace, but insurance companies are no longer allowed to deny coverage or charge higher premiums based on gender.

Last Congress also saw many improvements in women’s rights. Passage of the Lilly Ledbetter Fair Pay Act ensured the right of women and other workers to challenge unfair pay. And the reauthorization of the Violence Against Women Act expanded protections to once vulnerable groups.

We’ve made incredible progress in recent years, but there is still a great deal more to be done on behalf of women’s rights. In 1963, when the Equal Pay Act was enacted, women who worked full-time, year-round made 59 cents on average for every dollar earned by men. In 2009, women still earned only 77 cents to the dollar.

I’ve been a proud cosponsor of the Paycheck Fairness Act, which would provide a much-needed update to the 47-year-old Equal Pay Act by providing more effective remedies to women who are not being paid equal wages for doing equal work. It would also prohibit employers from retaliating against employees who share salary information with their co-workers. I will continue pushing for a vote on this important legislation.

Unfortunately, women continue to face opposition in this Congress. The continued Republican assault on the ACA jeopardizes many of the health care protections women now enjoy, which would leave them financially vulnerable once again. Just last year, the proposed Republican budget eliminated all funding for the Title X Family Planning Program and Planned Parenthood, whose health centers serve more than five million individuals each year with cancer screenings and other critical health services. I was proud to stand against this harmful bill, which died in the Senate.

This Women’s History Month, we should all take time to reflect on the steps we have taken towards equality and push for continued progress.