This depends on the type of birth control. With condom use, for example, 21 percent of women will get pregnant after a year with regular condom use. This number goes up if you only use condoms during ovulation because you can’t always predict when you will ovulate. You can also get pregnant with pulling out methods as you can get pregnant from just having precum in your vagina. Certainly, the chances are much higher to get pregnant if you have sex without a condom. Do not have unprotected sex if you don’t want to get pregnant.
You have lesser chances of getting pregnant with tubes tied or if you are on depo. If the tubes are tied, and a section is cut out of the tube, the chances of getting pregnant are much less. Depo Provera has a 1 in a thousand chance of getting pregnant while using it. The best chance of being pregnant while on depo is when you accidentally got pregnant before the depo shot was given.
You can get a girl pregnant with PCOS, but this is not easy. PCOS is a common cause of infertility, and you may need the advice and management of a fertility specialist to get pregnant. The same is true of a woman with endometriosis. Sometimes interventions are necessary to get pregnant and your odds of getting pregnant the first time you try are very low. The chances of getting pregnant on Nuvaring are about the same as being on a birth control pill.
The chances are less than one in a hundred, provided the ring is used correctly and at all times.