Four girls born with a rare defect called menstrual periods don't begin in a girl who appears to have otherwise reached reproductive maturity. With no opening to expel menstrual flow, it collects in the abdomen and can become quite painful.

Dr. Anthony Atala, director of the Institute of Regenerative Medicine at Wake Forest Baptist Medical Center in Winston-Salem, North Carolina, led the study which was conducted at the HIMFG Tissue Engineering Laboratory in Mexico City.

The four girls in the study were between the ages of 13 and 18 at the time the vaginas were surgically implanted. These surgeries occurred between June 2005 and October 2008.

To construct the vaginas, the research team took small biopsies from each girl's external genitalia. Muscle cells and epithelial cells were extracted from the biopsied tissue. Epithelial cells line all the cavities in the human body, including vaginas.

The research team constructed scaffold-like structures from biodegradable materials to form vaginas that would fit each girl. The scaffolds were then seeded with the extracted cells, where they multiplied.

After about six weeks, surgery was performed on each girl to create an opening and insert the scaffold. Over time, blood vessels and nerves began growing along the scaffold as more muscle and epithelial cells grew. Follow-up exams indicate the scaffolds have been absorbed as desired, the engineered tissue is indistinguishable from natural tissue, and the vaginas have grown as the girls' bodies have grown into adulthood.

Since surgery, the girls have all become sexually active without complication and two of them are having regular menstrual periods. There are no signs of rejection as the vaginas were engineered from the girls' own tissue.

The Atala team expects more clinical trials in the future to perfect technique and gain further understanding before the procedure becomes routinely offered to MRKH patients. Other likely candidates for this kind of regenerative medicine include women who have vaginal cancer or injuries that damage the organ.

Source: Atala, Anthony, MD, et al. "Tissue-engineered autologous vaginal organs in patients: a pilot cohort study." The Lancet. Elsevier Limited. Apr 11, 2014. Web. Apr 18, 20214.