Very irregular periods

[yonnie8]

DD turned 17 in August and she hoy her period when she just turned 11. Her periods have always been a little irregular but they came every month. Since about June she has been missing a few of her periods. June she had it but not July, August and September were both normal. Her last period was 8-14th September and she has not had one since and she does not feel as if it will come any time soon (no discharge or tenderness at all).
She has been losing weight since she was about 12 but nothing extreme. She has been on and off with weight loss but since the start of March she has not "given up for a bit" as she says.
Is this something to worry about or call the GP?
Thanks

How much weight has she lost? Could be iron deficiency? I think she needs to see the GP for a blood test.

@CastleOfDoom Yes I think I will do that. She was 53kg at age 12, 41kg in February and now she is 39kg.

I would be very, very concerned about her weight. Unless she is extremely short, 39kg is alarming. I would be suspecting an eating disorder.

@Aquamarine1029 She's only 140cm

Either eating disorder or she could be failing to absorb nutrients from her food. Coeliac disease would explain lack of growth and losing weight. www.isitcoeliacdisease.org

Isn't that about 7 stone in weight

Sorry www.isitcoeliacdisease.org.uk

@Pootle40 It's 6 stone
For her height it is 33rd percentile andshe looks healthy and has got a bit a fat.

@tinkerbellvspredator Thanks for the link :)
I shall look into that. She only grew about 5cm from about age 8 (breast bud stage) to 12 and hasn't grown since.
I never really thought about her height as I am only 150cm myself

Her height could also be a growth hormone issue perhaps. I'm only 5ft 2 myself but I believe anything under 5 foot they check for issues as I remember a friend at school having investigations although nothing was wrong in the end.

But equally it could be lack of vitamins/minerals etc if she's been on a diet for a very long time.

If she’s only 140cm at age 17 she’s way, way down, like off the charts on the percentiles for girls. There’s something unusual going on which definitely needs investigating. Also, I’m assuming you/she has checked she’s not pregnant?

@PaquitaVariation She has always been in all girls schools so definitely not pregnant!