A new study suggests a 'significant proportion' of schoolgirls suffer from period pain that is so bad it forces them to miss classes.

More than 1000 girls in the ACT aged between 16 to 18 were interviewed for the study led by obstetrician Dr Anne Sneddon from Canberra Hospital, the findings of which will be presented to the 10th World Congress on Endometriosis in Melbourne today.

Dr Sneddon found around 25 percent of girls in the study experienced "significant menstrual disturbance", marked by severe pain and high interference in life activities, including missing school.

Around 33 percent said they had gone to see their doctor about their periods.

"We cannot say that all of the girls have early stages of endometriosis," Dr Sneddon said.

"But for many there were symptoms that were highly suggestive of the disease."

Endometriosis occurs when uterine tissue grows where it is not supposed to, such as the ovaries and fallopian tubes.

It can lead to infertility for some women.