Congratulations on your child's birth. I would encourage you to talk to your OB/GYN. Each women is different, and therefore your specific details should be discussed with your doctor
To answer your question--it depends on if you are breastfeeding. If you are breast feeding, the levels of estrogen in your body remain elevated and therefore delay the return of ovulation. Overall, each women varies significantly.
If you do not breast feed, then the average women will start menstruation approximately two months after child birth. When one starts ovulating (and therefore can become pregnant) varies, but most will began around that time. Breastfeeding delays both of these, but how much it delays is variable. Therefore, breast feeding is not a good method of contraception.
Important to note, most OB/GYN doctors
will recommend that women not have sexual intercourse for the first six weeks after child birth in order to allow various gynecologic structures (vagina, uterus, etc) to heal.
So around 1-2 months after child birth is the earliest your ovulation will likely restart--which means you can become pregnant anytime after that. Keep in mind most birth control
pills effect breast feeding and diaphragms do not work in recently pregnant women. If you are sexually active and do not want to become pregnant once again, talk to your doctor.