Hello and welcome to MedHelp's forums. You can confirm the following with your own doctor but condom usage during intercourse is an effective way to prevent pregnancy. However, failure can occur. Please keep in mind, this is usually when someone has used the condom incorrectly or it breaks which is very noticeable. Pin holes are a myth as condoms break wide open and difficult to miss when this happens. The general rate of condom failure is 13 percent. https://www.cdc.gov/reproductivehealth/contraception/index.htm. However, again, if you did not have a condom break during intercourse, I would be inclined to believe it worked effectively at preventing pregnancy.