Can you tell me about a condition in which the uterus and other reproductive organs do not develop during puberty? What is the medical name for this condition, and how rare is it? My doctor called it "juvenile uterus," but I have not been able to find any information on it.

Edie

There is no such thing as "juvenile uterus." A uterus is a uterus. If it sees the normal level of hormones, it will grow to a normal size. This usually happens at puberty, but it can occur at other times. Given estrogen, even a toddler will develop a normal uterus.

Many conditions can cause estrogen levels to be lower than normal at puberty, so the uterus remains small. Causes such as constitutional delay of puberty (a physical interruption in normal development), stress, exercise and eating disorders (such as anorexia nervosa) must be considered. Constitutional delay often corrects itself. Lack of development related to diet, stress, exercise or eating disorders can typically be reversed with behavior modification. As soon as any of these steps are taken and normal estrogen levels return, the uterus will grow to a normal size. This should not be an impediment to fertility.

Another possibility is Kallman syndrome, diagnosed when the part of the brain that controls secretion of the hormones FSH and LH from the pituitary gland fails to develop. Kallman syndrome cannot be corrected. In this rare condition, hormone replacement allows puberty to proceed normally. When fertility is desired, injections of FSH and LH are needed to stimulate the growth of ovarian follicles (the structures that hold eggs).

A less likely possibility, based on your description, is a condition called Mullerian agenesis or Mullerian dysgenesis. This occurs when the either the uterus or vagina fail to develop during the formation of the embryo -- long before puberty. Occasionally only one side of the uterus forms. Luckily most women born with only half of the uterus (called a hemi-uterus) do fine when it comes to fertility. Mullerian defects may be associated with abnormalities of the kidney and spine, so if the uterine malformation is truly congenital (present at birth), then it's also a good idea to have X-rays of the spine and an X-ray study of the kidneys (called an intravenous pyelogram, or IVP).