If your daughter is going through puberty and one breast is not developing: This can be frightening and isolating. You are not alone, and there are good options. This page explains what is happening, why, and what can be done — at the right time.
What it looks like
During puberty, girls with Poland anomaly typically notice that breast development on the affected side is significantly less than on the other side. This can range from a breast that is noticeably smaller to one that is almost entirely absent. The nipple and areola on the affected side may also be smaller, higher, or differently positioned. In some cases, the nipple or areola is absent entirely.
Because this becomes most visible precisely when girls are already navigating the social and emotional challenges of puberty, breast asymmetry from Poland anomaly can be psychologically very difficult. Many girls feel self-conscious, avoid activities like swimming, and are reluctant to tell peers or even their own parents. This is extremely common and completely understandable.
Why it happens in Poland anomaly
In Poland anomaly, the pectoralis major muscle on the affected side is absent or underdeveloped. The breast, which sits on top of the chest wall and pectoral muscle, is affected in two ways: it lacks the normal muscular platform beneath it, and the breast tissue itself is often hypoplastic (underdeveloped) on the affected side. The extent of breast involvement varies — some girls have mildly smaller breasts; others have almost no breast tissue on the affected side.
This is not caused by anything the girl or her parents did. It is a consequence of the same random vascular disruption that occurred before birth.
When can reconstruction be done?
Breast reconstruction for Poland anomaly is typically recommended after the body has finished developing — generally at or after age 18, or once growth plates have closed and the other breast has reached its adult size. Performing reconstruction too early risks asymmetry as ongoing development changes the body's proportions.
Some plastic surgeons place a tissue expander in mid-adolescence — a device that gradually expands to keep the affected side roughly in pace with the developing other breast — with final reconstruction completed at or after 18. This approach is not universal, and the right plan depends on the individual's anatomy and the surgeon's assessment.
Reconstruction options include implant-based reconstruction, flap-based reconstruction (using the patient's own tissue), or a combination. A plastic surgeon experienced with Poland anomaly will discuss which approach is most appropriate for the individual's body and goals.
Living with asymmetry before reconstruction
The years between puberty and reconstruction can be emotionally challenging. Practical options that many girls and young women find helpful include:
- Prosthetics and mastectomy bras — Lightweight breast forms designed for post-mastectomy use fit discreetly and work well for Poland anomaly. Many insurance plans cover these as a medical device.
- Padded swimwear — Swimwear with built-in padding on one side is available specifically for breast asymmetry.
- Community — Connecting with other girls and young women who have Poland anomaly can be transformative. Organizations like the Lucky Fin Project and the Poland Foundation community include many young women who have navigated this experience.
- Counseling — A therapist experienced with body image and adolescent development can provide meaningful support during this period. This is not a weakness — it is a resource.
When to see a doctor — and which specialist
If you notice that your daughter's breast on one side is not developing, or developing significantly less than the other side, seek an evaluation with a pediatric plastic surgeon. An early visit — even if no immediate treatment is planned — establishes a relationship with the right specialist, confirms the diagnosis, and creates a plan for monitoring and eventual treatment.
Our specialist directory includes plastic surgeons with Poland anomaly experience. Our Teens & Puberty page addresses the emotional and social dimensions of this experience in more depth.