Talk to your doctor if you notice any big change in your cycle. It's especially important to check with your doctor if you have three or more menstrual periods that last longer than 7 days or are very heavy. Also call if you have bleeding between your periods or pelvic pain that is not from your period.
http://www.webmd.com/women/tc/normal-menstrual-cycle-topic-overview
During my ovulation time, how many days am I really fertile? During your window of ovulation, an egg is only available to be fertilized for about 12-24 hours. But since sperm can live in the body for 3-5 days after sex, and the egg is available for one day, your most fertile time is considered to be about 5-7 days.
http://americanpregnancy.org/getting-pregnant/ovulation-faq/
The menstrual cycle. The first day of your menstrual cycle is the first day of your period (day 1). The period usually then lasts anything from 3 to 7 days. You’ll probably find that if you get any period pains, they’ll be at their worst in the first few days of your period.
http://uk.clearblue.com/menstrual-cycles-and-ovulation
For most women, the length of time between ovulation (when an egg is released from the ovary) and their monthly period is between 12 to 16 days (this is called the luteal phase). The first day of your menstrual cycle is the first day of your period (day 1). The period usually then lasts anything from 3 to 7 days. You’ll probably find that if you get any period pains, they’ll be at their worst in the first few days of your period.
http://uk.clearblue.com/menstrual-cycles-and-ovulation
The egg can live for up to 24 hours. Sperm survival is more variable, but typically 3-5 days, so the days leading up to ovulation and the day of ovulation itself are your most fertile – when you are most likely to get pregnant. As soon as you have ovulated, the follicle starts producing another hormone: progesterone.
http://uk.clearblue.com/menstrual-cycles-and-ovulation
The menstrual cycle is from Day 1 of bleeding to Day 1 of the next time of bleeding. Although the average cycle is 28 days, it is normal to have a cycle that is shorter or longer. Girls usually start having menstrual periods between the ages of 11 and 14. Women usually start to have fewer periods between ages 39 and 51. Women in their 40s and teens may have cycles that are longer or change a lot.
http://www.webmd.com/women/tc/normal-menstrual-cycle-topic-overview
The number of days in your cycle is calculated by counting the number of days from the beginning of one period to the beginning of the next period. If you have a short cycle, for example 21 days, and you bleed for 7 days, then you could ovulate right after your period. This is because ovulation generally occurs 12-16 days before your next period begins, and this would estimate you ovulating at days 6-10 of your cycle.
http://americanpregnancy.org/getting-pregnant/ovulation-faq/
The Association estimates that ovulation occurs anywhere between 11-21 days after the first day of your last menstrual period (LMP), or 12-16 days from when you expect the next menstrual period to start.
http://americanpregnancy.org/getting-pregnant/ovulation-faq/
This is because sperm can live in a woman's body for up to five to seven days. The answer to how long after your period can you get pregnant will depend on the length of your menstrual cycle, but also on when you have intercourse during the month.
http://pregnancy.lovetoknow.com/wiki/How_Long_After_Your_Period_Can_You_Get_Pregnant
So the answer to how long after your period can you get pregnant depends on the typical length of a woman's menstrual cycle and the conditions inside her reproductive cavity. Women who want to get pregnant can try anytime up to a week before the cycle midpoint and a few days afterward.
http://pregnancy.lovetoknow.com/wiki/How_Long_After_Your_Period_Can_You_Get_Pregnant
how many days after your period is your next cycle
Your next cycle is 28 days after your period.