Most women should start getting mammograms at age 40 and repeat them every two years. This is the current recommendation from the U.S. Preventive Services Task Force (USPSTF), which updated its guidance to lower the starting age from 50 to 40. If you have certain risk factors, you may need to start even earlier.
Why the Starting Age Dropped to 40
For years, the USPSTF told women in their 40s to talk it over with their doctor and decide individually when to begin screening. That changed with the Task Force’s latest recommendation, which now calls for all women to start routine mammograms at 40. The shift was driven by evidence that breast cancer is being diagnosed more frequently in younger women and that the benefits of catching it early outweigh the downsides of screening in this age group.
The American Cancer Society takes a slightly different approach. Under its guidelines, women between 40 and 44 have the option to start yearly mammograms but aren’t told they must. From 45 to 54, the ACS recommends annual screening. After 55, women can switch to every other year or continue annually. Both sets of guidelines agree on one thing: by age 45 at the latest, you should be getting regular mammograms.
If You’re at Higher Risk, Start at 30
Some women need to begin screening a full decade earlier. The American College of Radiology recommends annual mammograms starting at age 30 for anyone with a lifetime breast cancer risk of 20% or higher. That includes women who carry a BRCA1 or BRCA2 gene mutation, have a first-degree relative (mother, sister, daughter) who carries one of those mutations, or received radiation therapy to the chest between ages 10 and 30.
For these high-risk individuals, mammography alone may not be enough. Guidelines also call for annual breast MRI starting between ages 25 and 30, because MRI can detect cancers that mammograms miss, particularly in younger, denser breast tissue. If you’re unsure whether you qualify as high risk, a risk assessment tool your doctor can run uses your family history, ethnicity, and reproductive history to estimate your lifetime probability.
How Often You Need One
The USPSTF recommends screening every two years from age 40 through 74. The American Cancer Society recommends annual screening from 45 to 54, with the option to move to every two years after 55. In practice, many doctors split the difference: yearly mammograms for women in their 40s and early 50s, then every other year after that.
The reasoning behind annual screening for younger women is that breast cancer tends to grow faster in premenopausal women, so a two-year gap between screenings could allow a tumor more time to develop. After menopause, cancers generally grow more slowly, which makes biennial screening a reasonable option for many women over 55.
The Trade-Off: False Positives
Starting screening at 40 does come with a cost, and it isn’t financial (more on insurance coverage below). It’s the higher chance of a false positive, meaning the mammogram flags something suspicious that turns out not to be cancer. Among women aged 40 to 49, roughly 121 out of every 1,000 mammograms produce a false-positive result. That rate drops to about 93 per 1,000 for women in their 50s and continues to fall with age.
A false positive typically means getting called back for additional imaging, sometimes an ultrasound or a second set of mammogram views. Occasionally it leads to a biopsy. These follow-ups can cause real anxiety, and the USPSTF acknowledges that lowering the screening age to 40 increases false positives by about 60% compared to starting at 50. It also leads to roughly 2 additional overdiagnosed cancers per 1,000 women over a lifetime of screening. Overdiagnosis means detecting a cancer that would never have caused symptoms or harm. Despite these trade-offs, the Task Force concluded the benefits of earlier detection outweigh these risks.
Dense Breasts Can Complicate Screening
About half of women have dense breast tissue, and density matters for two reasons. First, dense tissue and tumors both appear white on a mammogram, which makes cancers harder to spot. A tumor can essentially hide behind the dense tissue. Second, dense breast tissue independently raises breast cancer risk.
If your mammogram report says you have dense breasts (categories C or D on the density scale), you may benefit from supplemental screening. Options include breast ultrasound or breast MRI in addition to your regular mammogram. Federal law now requires mammography facilities to notify you about your breast density, so you’ll know from your results letter whether this applies to you.
When to Stop Screening
The USPSTF recommends routine mammograms through age 74, noting that no large-scale clinical trials have studied the benefits of screening beyond that age. The American Cancer Society takes a different position: keep screening as long as you’re in good health and expected to live at least 10 more years. The American College of Radiology doesn’t set a firm stopping point at all, instead encouraging individualized decisions.
What this means in practice is that a healthy 78-year-old with no major medical conditions might reasonably continue screening, while a 72-year-old with serious health problems might reasonably stop. The decision hinges less on a specific birthday and more on overall life expectancy and personal preference.
Insurance Coverage for Mammograms
Under the Affordable Care Act, most insurance plans must cover screening mammograms at no cost to you, with no copay or deductible, for women 40 and older. This applies to screenings every one to two years. If you’re under 40 and need early screening due to high risk, coverage varies by plan, so it’s worth calling your insurer before scheduling. Medicare covers annual mammograms for women 40 and older, also at no out-of-pocket cost.
Keep in mind that this zero-cost coverage applies to screening mammograms, the routine ones you get when you have no symptoms. If your doctor orders a diagnostic mammogram because of a lump, pain, or an abnormal screening result, different cost-sharing rules may apply depending on your plan.