The new rules require insurers to cover a comprehensive set of preventive services that the U.S. Department of Health and Human Services estimates will benefit 47 million women. They include contraceptives, breastfeeding supplies and gestational diabetes screening for pregnant women, prenatal care, routine breast and pelvic exams and pap tests used to detect potentially precancerous and cancerous processes in the cervix.
Other benefits that became effective Wednesday as part of a decade-long rollout of the Patient Protection and Affordable Care Act signed into law by President Barack Obama March 23, 2010, include testing for the human papillomavirus -- which can cause warts and, in a minority of cases, lead to cervical cancers -- screening and counseling for HIV and other sexually transmitted diseases and infections, and screening and counseling for domestic and interpersonal violence.
Healthcare-reform benefits for women already in effect include mammograms for women over age 40 for early detection of breast cancer and osteoporosis bone-mineral-density screenings for women over age 60 to prevent an increased risk of fracture.
"The top killers of women will now no longer go undetected," said Sen. Barbara Mikulski, D-Md., who spearheaded the Capitol Hill push to include Wednesday's requirement in the healthcare overhaul.
"Women will be able to have access to essential preventive services that will provide early detection and screening for those situations where they're most at risk, and also provide opportunities to care and services that they need as wives and mothers," she told reporters Monday.
Health and Human Services Secretary Kathleen Sebelius said, "Before the healthcare law, many insurers didn't even cover basic women's healthcare.
"Other care plans charged such high copayments that they discouraged many women from getting basic preventive services," she said. "So as a result, surveys show that more than half of the women in this country delayed or avoided preventive care because of its cost. That's simply not right."
Robert Zirkelbach, vice president for strategic communications for America's Health Insurance Plans, a national political advocacy and trade association with about 1,300 insurance-company members, said most health plans already covered preventive care, sometimes without a copay.
"In fact, not only do health plans cover these services, they encourage policy holders to get recommended preventive care, such as preventive tests, screenings and immunizations," he told CNN. "Promoting prevention and wellness has always been a top priority for health plans."
Americans are divided over the Affordable Care Act, the most significant U.S. healthcare system regulatory overhaul since the passage of Medicare and Medicaid in 1965 and Obama's signature legislative accomplishment. Several provisions already in effect are popular with the public, opinion polls indicate.
These include allowing children to remain on a parent's health plan until age 26, prohibiting the denial of coverage for pre-existing conditions and eliminating the maximum lifetime dollar limit for an insured individual's care.
Some insurance plans in force before the passage of healthcare reform may have "grandfathered" status and may be exempt from offering the new benefits, the non-profit, non-partisan, Kaiser Family Foundation said.
The foundation, which focuses on major U.S. healthcare issues as well as the U.S. role in global health policy, said it found in a 2011 survey that 56 percent of covered workers are in grandfathered plans, or plans in which old rules continue to apply to some situations.
Women can check with their employers to find out whether they are in grandfathered health insurance plans, Kaiser said.
Sebelius planned to answer questions from the public live online at 1:30 p.m. EDT at healthcare.gov/live. People may also submit questions over Facebook at facebook.com/healthcaregov or through Twitter using the hashtag #womenshealth.