In a breakthrough, US doctors have reported the first ever case of a transgender woman successfully breast-feeding her baby.

According to the doctors at the Icahn School of Medicine at Mount Sinai, the 30-year-old transgender woman underwent a three and half months of a regimen of domperidone, estradiol, progesterone, and breast pumping. As a result, she was able to achieve sufficient breast milk volume to be the sole source of nourishment for her child for six weeks. The case, published in the journal Transgender Health, illustrates that in some circumstances, modest but functional lactation can be induced in transgender women.

"We believe that this is the first formal report in the medical literature of induced lactation in a transgender woman," said Tamar Reisman, endocrinologist and Assistant Professor at the varsity. The woman explained that her partner was pregnant but not interested in breastfeeding, and that she hoped to take on the role of being the primary food source for her infant. She had been receiving feminising hormone therapy for the past six years as well as was being treated for insomnia and anxiety, but otherwise appeared to be a "pleasant, well-nourished, well-developed woman", Reisman said.

However, the patient had not underwent any gender reassignment surgeries, breast augmentation or vaginoplasty. The study showed that the patient underwent a treatment with the female hormones progesterone and estradiol, stimulating her chest with a breast milk pump, and intake of domperidone -- a nausea medication known to increase milk production and suppress testosterone for three and half months.

A month later, the patient began producing "droplets" of milk, and post three months, she produced about eight ounces of milk per day, Reisman said. After the birth of the baby, weighing 6lbs 13oz, the patient breastfed exclusively for six weeks, during which the baby's paediatrician commented that "the child's growth, feeding, and bowel habits were developmentally appropriate." Later, the patient began supplementing breastfeedings with 4-8oz of Similac brand formula daily due to concerns about insufficient milk volume, Reisman said.