Thank you for your question.
Yes having intercourse can lead to becoming pregnant. With every cycle you have approximately 30-40% chance of pregnancy. If cycles are regular and the couple is fit and healthy the cumulative pregnancy rate over one year is 85% and two years is 90%. If you wish to get pregnant you need to take folic acid to protect the baby's neural tract when you conceive.
If you do not wish to get pregnant just yet you need to use regular reliable contraception in addition to using condoms.