There isn’t a blanket legal or society rule that requires a mammogram before fat transfer to the breast for everyone  age 40 or above. In practice, though, many surgeons ask patients 40 and older to be up‑to‑date with age‑appropriate screening.

Why the answers differ by setting

• United States (general practice): The American Society of Plastic Surgeons’ Choosing Wisely list advises not ordering “routine” pre‑op mammograms beyond what standard screening already recommends—unless there’s a specific concern on history or exam. So if you’re 40 years old and above, you should be current with your regular screening schedule; surgeons typically don’t add an extra mammogram solely because of the surgery. (American Society of Plastic Surgeons)

• United Kingdom: A joint guideline from the British Society of Breast Radiology, Association of Breast Surgery, and BAPRAS recommends a two‑view mammogram before aesthetic breast surgery (including fat transfer) in women age 40 or over if one hasn’t been done in the previous 12 months. (Association of Breast Surgery)

• What many specialists do: Review articles from breast reconstruction/oncology teams recommend screening mammography before autologous fat grafting in patients age 40 or over with risk factors (family history, dense or cystic breasts, abnormal exam). This isn’t a law, but it’s common pre‑op practice to avoid missing an occult issue and to establish a baseline. (Gland Surgery)

What “age‑appropriate screening” means (U.S., average risk): Current USPSTF guidance recommends biennial screening mammography from ages 40 to 74; some other bodies favor annual screening. Being “up‑to‑date” with whichever schedule you and your clinician follow generally satisfies pre‑op needs. (USPSTF)

When a pre‑op mammogram is typically expected regardless of country:

• Any new breast symptom (lump, bloody nipple discharge, skin/nipple distortion)

• Personal history of breast cancer or strong family history/BRCA risk

• Abnormal clinical exam or dense/cystic breasts noted on evaluation
  In these situations, pre‑op imaging is recommended even under conservative policies. (Association of Breast Surgery)

After fat transfer: Benign changes such as fat necrosis or oil cysts can appear on imaging, but experienced breast radiologists can usually distinguish these from suspicious lesions, and fat grafting has not been shown to delay cancer detection when surveillance is appropriate. (American Society of Plastic Surgeons)

Bottom line if you are considering breast fat transfer and are age 40 or above:

• In the U.S., a mammogram is not automatically required, but you’ll usually be expected to be current with routine screening; many surgeons still prefer a recent (≤12‑month) mammogram before operating. (American Society of Plastic Surgeons)

• In the U.K. (and some other systems), a pre‑op mammogram is recommended for women age 40 or above if one hasn’t been done in the past year. (Association of Breast Surgery)

If you’re scheduling surgery, the safest path is to check your last screening date and ask your surgeon whether they require a mammogram within a specific window; if you have any breast symptoms or elevated risk, get imaging before surgery.