If you and youre partner are trying to (or not to) get pregnant, an important aspect when understanding your chances of conception is being aware of that fertile window, and days when chances are the highest. This comes with tracking your menstrual cycle and making a note of when youre ovulating.That said, most women tend to be under the impression that they cannot conceive while theyre on their period. While the chances of pregnancy are lowered, theyre not nil. According to Dr Vaishali Joshi, senior obstetrician and gynaecologist at Kokilaben Ambani Hospital, Mumbai, If couples are looking to get pregnant and start a family, having sex during periods is counterproductive as ovulation doesnt take place during menstruation. However, sperm has the ability to live for up to 72 hours, so having sex towards the end of your cycle can lead to pregnancy if your fertile window begins soon after. You will have to understand and track your cycle for accuracy.When can conception occur?The ability to conceive requires the fertilisation of the egg by the sperm. However, in order for conception to occur, both the sperm and the ovum must be present to enable fertilisation. Says Dr Joshi, Conception occurs usually after ovulation, and ovulation depends on the period cycle. Typically, this happens mid-cycle. In a 28-day cycle, the fertile window is usually between days 12 to 18.Conception on periodAs stated above, a typical cycle is 28 days. However, there are some women who experience a shorter cycle, and as such, have a shorter window between their last period and ovulation. However, for some women, a little bleeding or false period might occur during ovulation, and thats the time in the cycle that a woman is most fertile. Bleeding during ovulation is uncommon, and is experienced by only two to three per cent of women. However, more commonly, ovulation is associated with pelvic discomfort than bleeding. This bleeding is light, can manifest as spotting, and may last for 24 to 48 hours in between two periods, explains Dr Joshi.So what does this mean for conception? If you have a shorter cycle than the typical 28-day cycle, you need to pay careful attention and track your ovulation. Another aspect to factor in is the lifespan of the sperm. If not vigilant, conception can occur even while on your period so proceed with caution, advises Dr Joshi.The takeaway?Its no secret that a womans ovulation cycles can vary. That said, having regular unprotected sex while on your period, particularly towards the end of your menstrual cycle, makes it statistically possible to conceive.