LONDON, April 19 Women supplied with birth-control pills for emergency contraception had an equal chance of becoming pregnant as women with no pills, says a British study.Eight studies of more than 6,000 women in the United States, India and China were reviewed in The Cochrane Library. It found that emergency contraception use was higher among women given an advance supply of the birth-control pills but that increase in use did not translate to a drop in the pregnancy rate.Plan B is a brand of emergency contraception pills that must begin within five days after unprotected sex."Even though advance provision increased use, we don't know if women were using emergency contraception at the times when they were at risk for pregnancy, when it was really needed," lead reviewer Chelsea Polis said in a statement. "If women aren't going to use Plan B when they are given it for free in a clinical trial and are counseled beforehand about using it every single time they have unprotected sex, then having to go to CVS and having to pay $45 each time -- it isn't going to happen." Copyright 2007 by UPI