Condoms remain the only pregnancy prevention method that can also prevent sexually transmitted diseases, but not all brands are equal, tests show.

Morning-after pill

Easy access to a "morning-after pill" has no influence on the sex habits of young women, U.S. researchers say.

The study was designed to test if the emergency contraception known as Plan B or Levonorgestrel could safely cut the number of unwanted pregnancies.

The team found the sex habits of young women remained unchanged regardless of whether they had access to emergency contraception.

The six-month study followed 2,117 women age 15 to 24 in two San Francisco Bay Area cities who all said they wanted to avoid pregnancy.

Participants were randomly assigned to go to pharmacists for emergency contraception without needing a prescription, given three doses in advance, or were told to go to a clinic for the drug.

The study appears in the Jan. 5 issue of the Journal of the American Medical Association.

The nonprofit Consumers Union, known for its Consumer Reports car and other product ratings, has published a guide to contraception.

The group tested the strength of different brands of condoms, which were compared to other methods of birth control.

Of the 23 brands of latex condoms tested, the seven top types did not burst when filled with air. All met minimum industry standards.

The Durex Extra Sensitive Lubricated Latex brand performed best in strength tests. Others brands that scored well were the Durex Performax Lubricated, Lifestyles Classic Collection Ultra Sensitive Lubricated and TheyFit Lubricated.

Conversely, condoms distributed by Planned Parenthood performed the worst in the burst test.

The tests suggested price, thickness and country of manufacturer didn't matter.

Spermicidal condoms offered no extra benefits in preventing pregnancy, had a shorter shelf life and may cause urinary-tract infections in young women, the report said.

There is no accepted way to test non-latex condoms, although the group noted manufacturing standards are now more effective and universal across the industry.

The safety of intrauterine devices or IUDs has also improved, as have birth control pills and so called morning-after pills or emergency contraception.