Japan has begun trial sales of emergency contraceptive drugs to see whether they can be safely sold over the counter without a doctor's prescription.

The so-called "morning-after pills" can prevent unwanted pregnancies to a certain extent if taken within 72 hours of unprotected sex.

The Japan Pharmaceutical Association on Tuesday began offering the pills at 145 drugstores nationwide.

Women aged 16 and older who have agreed to cooperate with the study can purchase them. Sixteen and 17-year-olds need a parent or guardian's approval.

The drugstores can introduce girls under 16 to obstetricians and gynecologists.

The pills will be priced between 7,000 and 9,000 yen, or about 47 to 60 dollars.

Drugstores selected for the study must meet certain conditions, such as having trained pharmacists able to provide pills at night, on weekends and on holidays. They must also have a private consultation room.

They can also refer women who take the pills to a nearby OB-GYN clinic.

Information on participating pharmacies is available on a special website.

Purchasers will be asked to answer questionnaires, which will be used in the study.