irregular/low-frequency periods for my 25 year old daughter - pregnancy

My daughter got her puberty at 12 and she had her periods fine until about 18 when we she started going to the university and living and eating in the dorm.

From age 18 to until now (she is 25 now), she gets periods roughly every 45 days.

We have consulted with gynecologists and endocrinologists.

She started having hormonal imbalance issues from age 18 for which she is taking medication.
She is somewhat overweight for her height and age. Her weight now is 58 kg and height 5ft  1 inch.

However, the gynecologists told that her periods are fine even though she gets every 45 days. They told that her irregular periods problem will solve itself once she gets married and gets sexually active. They asked her to watch diet i.e. no carbs and exercise.

I would like to know.

- how would irregular periods problem get fixed once she becomes sexually active after marriage? she is virgin as of now.

- is it common among women between ages 20-25 to have irregular/low-frequency periods of 45 days or so? is it common or very few girls have it? our gyno told us that it is common.

- our gyno also told us that some girls develop irregular/low-frequency periods after becoming sexually active while some girls who already have irregular//low-frequency periods, get fixed after becoming sexually active. This did not make sense to me. is it true?

- can she have any pregnancy issues?

- can she have PCOS as she has harmonal imbalance as well?

Thanks in advance.

[Shirano]

I have irregular periods I have ever since I started having them. I am married and sexually active it didn't make them regular. I am now 23 weeks pregnant so you can get pregnant with irregular periods. Those are all the answers I have.

[medicine23]

Thanks for the reply. May I know your period frequency and if your age group is similar to my daughter? do you have harmonal issue and weight issue like my daughter? did you get pregnant with or without help of medical assistance?

Sorry for asking too many questions. I am just concerned for my daughter and we live in a developing country.

[Shirano]

I had my period about every other month most of the time. Although sometimes I would have a period twice a month after having skipped. It was really weird. I'm 21 and by the BMI scale Im slightly overweight. No hormone issues that I know of. And I got pregnant without medical assistance.