Ovulation is a release of a mature egg from an ovary. It usually occurs 14 days after the first day of your menstrual cycle.
Your fertile period starts about 3 to 5 days before and ends about 24 hours after ovulation. A sperm can live in your body for 3 to 5 days, and an egg can live for 12 to 24 hours after being released. You are most fertile on the day before and the day of ovulation. Knowing your fertile days can help you increase your chances of conceiving.
It is important to remember that the sperm has to be in the woman's body BEFORE ovulation: the egg disintegrates within 12 to 24 hours, whereas sperm can last up to five days.
The female reproductive cycle is a complex string of events that take place each month while the body prepares for potential pregnancy - regardless of whether you intend to get pregnant or not.
The whole thing is very much a cycle, repeated every month (unless pregnancy occurs), with preparations for the next one beginning before your period even starts.
The number of days between the first day of your menstrual period to the first day of your next menstrual period is taken as one menstrual cycle. Although the average cycle is generally considered to be 28 days, this varies from person to person, and cycle to cycle.
During ovulation you may experience lower abdominal pain or discomfort, breast tenderness, a slight rise in body temperature, and changes in cervical mucus. Many women feel discomfort or pain in their lower abdomen as the egg leaves the ovary. This condition usually lasts from a few minutes to several hours. Immediately following ovulation, your body temperature can increase by 0.4 to 1.0 degrees Fahrenheit. Before ovulation, your cervical mucus is thicker and a couple of days before ovulation it becomes clear and stretchy like raw egg whites.
Luteal Phase
Your cycle can be divided into two sections - the "follicular" or pre-ovulatory phase, and the "luteal" post-ovulatory phase. Ovulation forms the dividing point in the cycle.
The luteal phase of your cycle is the number of days between ovulation and the last day of your menstrual cycle. This is usually between 12 and 16 days. The luteal phase should be at least 10 days for a fertilized egg to be able to implant in the uterus and develop into a baby.
Your Period
Your period (menstruation) is the body discharging the endometrium it prepared for the uterus in case there was a fertilised egg the previous month. Day 1 of your cycle is the first day of red menstrual flow. During your period you also create FSH - Follicle Stimulating Hormone which prompts follicles in both ovaries to begin maturing eggs.
Increasing amounts of oestrogen trigger a surge of Luteinising Hormone (LH) and the strongest egg bursts through the wall of the ovary. This is ovulation, and you're now at your most fertile. The egg is caught by fibria at the entrance of the fallopian tube and directed towards the uterus. If there are sperm waiting, fertilization would occur in the fallopian tube.
Having released the egg, the surrounded follicle collapses and becomes a "corpus luteum" You are now in the "luteal" phase. Anticipating successful fertilization of the egg, the corpus luteum produces progesterone which helps build up a healthy endometrium (lining for the uterus) for implantation.
If the egg hasn't been fertilised it disintegrates within 6-24 hours. The corpus luteum continues producing progesterone for a few more days, which differs from person to person, but is more or less constant for each person. At the end of that time the corpus luteum disintegrates and - because it's no longer producing progesterone - the drop in that hormone causes the lining of the uterus to begin to disintegrate and discharge. In other words, your period begins.
If the egg is fertilised it continues down the fallopian tube. It arrives in the uterus a week or so later to gently burrow and implant itself into the endometrium and develop into a healthy foetus. Once implanted it generates hCG which helps ensure the endometrium doesn't disintegrate. Pregnancy tests look for this hormone to confirm that you are pregnant.
You were born with all your follicles, meaning the number of eggs you can produce in your lifetime. So once you reach puberty, all that is left for you to do, is "ripen" them in the follicular phase of each cycle. Once your healthy follicles have all been used you are no longer fertile – you reach menopause.
See pictures of the menstrual cycle - see how it happens
SPECIAL NOTE
Recent researchers have stumbled on the unexpected discovery that ovulation and menstruation cycles do not always move in unison in many women, meaning that ovulation does not always take place on the same days in every menstrual cycle.
Sometimes two eggs are released from the ovary with a gap of 10 days. But keeping track of such irregular ovulation will require you to go for more sophisticated methods of conception planning like frequent ultrasound scans while our interest here is low tech, low cost do at home methods.