The current recommendation is to start getting mammograms at age 40. The U.S. Preventive Services Task Force (USPSTF) updated its guidelines to recommend screening every two years from age 40 through 74 for people at average risk of breast cancer. This was a significant shift, as the task force had previously suggested most women could wait until 50.
What the Major Guidelines Recommend
The major medical organizations in the U.S. now largely agree on age 40 as the starting point. The USPSTF, the American College of Obstetricians and Gynecologists (ACOG), the National Comprehensive Cancer Network, the American College of Radiology, and the Society of Breast Imaging all recommend beginning routine screening mammography at 40.
Where they differ slightly is on how often. The USPSTF recommends every two years (biennial screening). ACOG recommends every one or two years, leaving the exact frequency to a conversation between you and your doctor. The reasoning behind annual screening is straightforward: a large review of modeling data found that annual mammograms for women starting at 40 reduced breast cancer deaths by about 42%, compared to a 30% reduction with every-other-year screening starting at the same age. That gap matters, though the tradeoff is a higher chance of false alarms along the way.
These guidelines apply to cisgender women and all other people assigned female at birth, including transgender men and nonbinary individuals.
If You’re at Higher Risk, Start at 30
Some people need to begin screening a full decade earlier. The American Cancer Society recommends that women at high risk get both a mammogram and a breast MRI every year starting at age 30. You fall into this category if you have a known BRCA1 or BRCA2 gene mutation, or if risk assessment tools estimate your lifetime chance of breast cancer at 20% to 25% or higher. These tools are based primarily on family history, particularly having a first-degree relative (mother, sister, or daughter) diagnosed with breast cancer.
If you’re unsure whether you qualify as high risk, the key factors are a strong family history of breast or ovarian cancer, a personal history of chest radiation before age 30, or known genetic mutations. Your doctor can run a formal risk assessment that takes your specific history into account.
When to Stop Screening
The USPSTF’s recommendation covers ages 40 through 74. After that, the evidence becomes less clear, but federal preventive health guidelines state that age alone should not be the reason to stop screening. The more relevant factor is overall health. If you’re in good health and have a life expectancy of at least 10 years, continuing mammograms past 74 is reasonable. If you have serious chronic conditions that limit life expectancy, the potential harms of screening (unnecessary biopsies, anxiety from false positives, treatment of cancers that would never have caused symptoms) start to outweigh the benefits.
What False Positives Look Like
One of the real downsides of starting mammograms at 40 is that younger breast tissue is denser, which makes images harder to read. False positives occur in 10 to 12% of mammograms for women in their 40s. That means roughly 1 in 9 screening mammograms in that age group will flag something that turns out not to be cancer.
Over time, these add up. After 10 years of annual screening, 50 to 60% of women will have experienced at least one false positive result, and 7 to 12% will have had at least one false positive that led to a biopsy recommendation. A false positive doesn’t mean something went wrong with the test. It means you’ll be called back for additional imaging, like a follow-up mammogram, ultrasound, or MRI, and possibly a biopsy. Most of those come back clear, but the waiting period can be stressful, and the extra procedures take time. Research from UC Davis Health found that false-positive results actually discourage some women from returning for future screenings, which is the opposite of what you want.
This is one reason some guidelines offer the option of every-other-year screening rather than annual. Screening every two years cuts the cumulative false-positive rate roughly in half while still catching the vast majority of dangerous cancers.
What Insurance Covers
Under the Affordable Care Act, most health insurance plans are required to cover recommended preventive services with no copay, coinsurance, or deductible. Screening mammography falls under this mandate. Federal guidelines specify that average-risk women should start no earlier than 40 and no later than 50, with screening occurring at least every two years and as frequently as annually.
If your screening mammogram finds something that needs a closer look, the additional imaging (ultrasound, MRI, or diagnostic mammogram) and any pathology evaluation needed to complete the screening process are also recommended to be covered. That said, coverage details vary by plan, so it’s worth confirming with your insurer before scheduling follow-up tests to avoid unexpected bills.
Choosing Between Annual and Every-Two-Year Screening
For most women at average risk, the practical choice comes down to annual or biennial mammograms starting at 40. Neither option is wrong. Annual screening catches more cancers earlier and offers a larger reduction in deaths. Biennial screening still provides strong protection while cutting down on false positives, callbacks, and unnecessary biopsies.
Your personal risk factors can help tip the balance. If you have dense breast tissue (your mammogram report will tell you), a family history of breast cancer that doesn’t quite meet the high-risk threshold, or other factors like early menstruation or late menopause, annual screening may offer more peace of mind and a meaningful edge in early detection. If you have no significant risk factors and want to minimize the chance of a stressful false alarm, every two years is a well-supported choice.