Eight million packets of "emergency" contraceptive pills are bought over the counter each year - many by under-age girls, academics revealed at a seminar in Bangkok yesterday.
They urged health officials to teach young women about proper use of the pills, which have more hormones than normal contraceptive pills, because many teenagers look to be using them in a bid to stop unwanted pregnancies.
Speaking at the Miracle Grand Convention Hotel, Chulalongkorn University pharmacy lecturer Niyada Kiatying-angsulee quoted a "worrying" report that said pharmacies sold 8 million sets of emergency pills annually. She said this showed the pills were being used too often.
Thai teenagers also had misconceptions about the pills, such as believing that they were 100 per cent effective, when they only had efficacy of 70-90 per cent. They seemed to believe the pills could be used any time, but a person should not take them more than twice a month, she said.
Chulalongkorn obstetrics and gynaecology lecturer Dr Annop Jaisamram said there were misunderstandings while the number of women using the pills was growing - despite the fact they were meant to be for emergencies such as sexual assault or in the event of a broken condom.
Chulalongkorn Hospital got many patients with excessive menstrual bleeding who had said they took the emergency pill up to five times a month or two to three times a week, he said, urging that it must be used carefully.
Over-use of the pill might cause side effects more than just nausea or vomiting. And it could not stop young women getting pregnant, as it only extended the ovulation period, and would only be up to 90 per cent effective if taken promptly after sex.
Dr Kittipong Saejeng, director of the Health Department's reproductive-health office, said interviews at pharmacies by Chiang Mai University researchers found that nearly a third (30 per cent) of people buying the emergency pill were teens aged from 13-15.
A poll by Health Department officials in 2009 of youths from Prathom 6 up to vocational-college level found that 60 per cent of those who had used the emergency pill did so after their first sexual encounters.
Dr Kittipong said use of the emergency pill needed to be studied, and young people needed to be educated about proper usage.