Beginning at age 40 until age 45, a woman's chance of conceiving drops to around 30 percent, according to Fertility Authority. After age 45, there is only a 5 percent chance a woman will get pregnant naturally.
Not only is a woman's chances of getting pregnant slim in her 40s, but the chance of miscarriage increases dramatically. Between the ages of 40 and 45, there is a 30 percent chance a woman will not carry the baby to term. Miscarriage rates for women over the age of 45 jumps to 50 percent.
Sometimes fertility treatments can help. Around 17 percent of in vitro fertilization treatments using the woman's own eggs are successful and result in a live birth. Close to 50 percent of in vitro treatments using donor eggs are successful.