ROCHESTER, Minn., May 13 (UPI) -- U.S. researchers said couples using in-vitro fertilization have the same success getting pregnant whether the sperm used is frozen or fresh.
Researchers said studies conducted at the Mayo Clinic from 1993 to 2003 using both fresh and frozen sperm in more than 1,900 in-vitro fertilization attempts showed fresh sperm succeeded 51.6 percent of the time while frozen sperm actually succeeded 53.1 percent of the time.
"Without these data, we were concerned that frozen sperm might reduce the birth rate," said Alan Thornhill, director of the the clinic's in-vitro fertilization laboratory. "Now, we believe that concern is unwarranted."
In-vitro fertilization involves women taking fertility drugs to stimulate their ovaries to produce more eggs than usual. When the eggs are mature, they are retrieved from the ovary and introduced to sperm. Using frozen sperm increases the chances it will be available exactly on time to fertilize an egg.
