anytime. and i mean anytime that you have unprotected sex and are not using any form of effective birth control you can potentially become pregnant. your body is designed to become pregnant not prevent it. i am reading between the lines of your brief question but i am assuming you feel that your weight gain could be a sign of pregnancy. obviously not all unintentional weight gains are due to pregnancy but you would need to take a home pregnancy test to determine if you are pregnant or not. weight gain can be an expected response to excess calorie intake or the retention of water. be more careful if you do not want an unplanned pregnancy. if you cannot use an effective form of birth control for any reason insist that your partner use a condom. every time. you are one who should be in control. given the choice of using a condom or not having sex most men will choose condoms.
had sex october 29th and my boyfriend came inside me my period is not due until november 12 th. ive gained weight