In vitro fertilization has come a long way since 1978, when the birth of the first "test tube" baby in Britain made news around the world. IVF works, but researchers have always judged how well, based on one cycle of trying.

A new study, just published in the New England Journal of Medicine, looks at the cumulative results of almost 250-thousand IVF patients who tried multiple times from 2004 through 2009. The researchers say results show that with the right woman and the right egg live birth rates through assisted reproductive technology can equal those of normally fertile females.

Births among older women were lower than those among younger women when their own eggs were used. But donor eggs helped level the playing field for older would-be moms. In fact, when donor eggs were used, success rates ranged from 60-to-80 percent for all ages.

The authors hope this data on long-term success rates can help doctors counsel their patients at the start of any fertility treatment.

I'm Dr. Cindy Haines of HealthDay TV, with the information you need to protect your health.