Primary amenorrhoea is the failure of your first menstrual period (menarche). It is normal for girls to start their periods between ages 9 and 12, so when this doesn’t happen, we need to find out why, though there is no need to panic before age 15 – some of us are just a little late to the party. Sometimes other puberty signs will be missing too (underarm hair, pubic hair, growth of labia, etc.).
No period after age 15 means something is going wrong somewhere along the line. Sometimes these things can be serious, like missing uteruses, or they could be more manageable, like being too skinny.
Why does this happen?
There are a handful of causes, and they all have quite different implications.
- A blockage or narrowing of the cervix (cervical stenosis), causing blood to back up in the uterus
- The hymen completely covers the vaginal opening so no blood can exit the vagina (an imperforate hymen)
- The vagina, uterus or cervix are missing (vaginal agenesis, uterine/Mullerian agenesis, cervical agenesis)
- The vagina, uterus, or cervix are not properly formed (vaginal hypoplasia, uterine hypoplasia, cervical hypoplasia)
- A transverse vaginal septum that blocks flow of blood out of the vagina
- The ovaries aren’t working properly – possibly due to tumours or hormone dysregulation – no ovulation generally means no period
- The areas that deal with hormones are not functioning properly (pituitary, thyroid, adrenals) – dysfunctional hormones means no ovulation/disrupted hormone triggers
- Low weight – skinny girls don’t have the required percentage of body fat for proper hormone production
- Unknown causes
- Genetic conditions such as Kallmann syndrome or anatomical abnormalities caused by genetic defects
As you can see, there is quite a range of reasons why you might not have your period yet. So next is an appointment with your doctor to find out why. Also check out secondary amenorrhoea, since some of these like over-exercising and low weight are covered in more detail there.
What the doctor might discover
- Underlying illness – cystic fibrosis, heart problems, chronic illness
- A genetic blip that has resulted in you growing differently in the womb (see DSD for more information)
- Poor nutrition and low weight (possibly linked with eating disorders or illness)
A physical examination will be done, with questions regarding your medical history. A pregnancy test will be done. Blood tests may include a range of hormone tests, including oestrogen and thyroid hormones. Imaging scans may be taken to establish what lies beneath your flesh in your pelvis – if you are missing organs or even have duplicates.
Treatment and management
Treatment depends entirely on why your period was missed, so see the separate sections for each topic for more information.