Technically speaking, it is extremely unlikely for conception to occur any time other than during ovulation. Once ovulation is over, there is not generally egg for the sperm to fertilize. Having said that, it is important to understand exactly how the process of conception works, and how it relates to ovulation.

Conception occurs when a sperm meets up with an egg and fertilizes it in a woman’s fallopian tube. That fertilized egg then travels into the uterus, where it implants in the wall of the uterus several days later. The only time during a woman’s monthly cycle that there is an egg in her fallopian tube is, by definition, when she is ovulating. The egg can survive for only about one day when it is in the fallopian tube. For some women, it is possible that an egg could survive as many as three days after ovulation, and thus conception could occur. This is extremely rare. For conception to occur, the sperm has to meet the egg pretty much immediately when you ovulate.

Still, there are things that may make it seem like conception occurs after ovulation. For example, during a given month, it is possible that ovulation would occur later than it usually does. Any number of factors can cause this to happen, including illness, dietary changes, increase in physical activity, and even stress. Ovulation can sometimes occur as much as a week after it normally does.

In some extremely rare cases, it may be possible for it to seem as though you conceived while you are on your period. For example, if you have an extremely short menstrual cycle, it is possible that you could begin ovulating right as you are done menstruating. Another possibility is if you tend to bleed for a long period of time during your period. If this is the case, it could be that you are still bleeding long after you are actually done menstruating, and while you are actually ovulating.

If you are trying to conceive, there are certain times surrounding ovulation that you will want to try to conceive. Sperm can often survive as long as one week in a woman’s body. Thus, trying to conceive on the 10th, 12th, 14th, and 16th days of your monthly cycle are the optimum times for conception to occur. This assumes that you have a regular 28-day cycle, and it allows for later-than-normal ovulation.