Ovulation happens when the mature egg is ejected from the ovary. The time of the menstrual cycle and ovulation is one of the most important things a woman should understand about her body since it is the determining factor in getting pregnant and preventing pregnancy.
The process can be confusing and somewhat overwhelming when trying to understand. If you still have further questions regarding ovulation, it may be helpful to talk with your health care provider. Being informed on what your body does, can help you feel more in charge of your health.
So, what is actually happening inside your body each month? It’s all about hormones. And more importantly, it's all about thebig O: ovulation.
A menstrual cycle is the time period between your first day of your menstrual period, the time you bleed, until the next time of your menstrual period.
The changes associated with ovulation and menstrual cycle are brought on by fluctuations in hormones at different times of the month. Most menstrual cycles are 28-29 days long - a variation of a few days more or less can be quite normal and small variations from cycle to cycle are also normal.
Cycle Day 1 (CD1) of the menstrual bleeding is referred to as Day 1 of the menstrual cycle. The length of the cycle is measured from Day 1 of one cycle (bleed) to Day 1 of the next cycle (bleed).
Your menstrual cycle length and the day of ovulation are directly related. Your menstrual period begins about 14 days after you ovulate. If ovulation occurs on approximately day 14 of a woman’s cycle then your next period starts about 14 days later and the cycle length is 28 days.
Ovulation happens when a mature egg is released from the ovary. It is then picked up by the fallopian tube and is available to be fertilized. The lining of the uterus has thickened to prepare for a fertilized egg. If no conception occurs, the uterine lining as well as blood will be shed. The shedding of an unfertilized egg and the uterine wall is the time of menstruation. The menstrual cycle can be divided into the following parts:
- Ovarian cycle
- Uterine cycle
The ovarian cycle involves changes in the ovaries, and can be further divided into two phases:
- Phase 1 of the Ovarian Cycle: Follicular Phase
The follicular phase (days 1 through 13) is the time from the first day of menstruation until ovulation, when a mature egg is released from the ovary. It's called the follicular phase because growth or maturation of the egg is taking place inside the follicle, a small sac where the egg matures. Ovulation occurs around day 14 of the cycle, in response to a surge of luteinizing hormone (LH) when the egg is released from the ovary. This first half of the cycle can differ greatly for each woman lasting anywhere from 7 days until 40 days.
- Phase 2 of the Ovarian Cycle: Luteal Phase
The luteal phase (days 14 through 28) is the time from when the egg is released (ovulation) until the first day of menstruation, when you get your period. It is a structure that grows in the ovary where a mature egg was released at ovulation. The luteal phase has a more precise timeline and usually is only 12-16 days from the day of ovulation. This ultimately means that the day of ovulation will determine how long your cycle is.
Cervical mucus changes according to ovulation and your menstrual cycle.
- Cycle Day 1-5: Menstrual bleeding
- Menses Cycle 6-9 (5-8 days before ovulation): Dry; little or no mucus
- Cycle Day 10-12 (2-4 days before ovulation): Sticky thick mucus, becoming less thick and whiter
- Cycle Day 13-15 (1-2 days before and after ovulation): Egg-white or "spinnbarkeit" mucus (most fertile time): thin, elastic, slippery, stretchy, clear
- Cycle Day 16-21 (2+ days after ovulation): Sticky, thick mucus (Less fertile/infertile)
- Cycle Day 22-28: Dry mucus
The old thought that stress can affect your period is only partly true. Stress can affect your ovulation which ultimately determines when your period will come, but stress around the time of an expected period will not make it late—it was already determined when it would come 12-16 days earlier!
- An egg (ovum) lives no longer than 12-24 hours after ovulation, after leaving the ovary
- Normally only one egg is released each time of ovulation, but occasionally two or more eggs are released
- Ovulation (and then your menstrual cycle length) can be affected by stress, illness or disruption of normal routines
- Some women may experience some light blood spotting during ovulation
- Implantation of a fertilized egg normally takes place 6-12 days after ovulation
- Each women is born with millions of immature eggs that are awaiting ovulation to begin
- A menstrual period can occur even if ovulation has not occurred
- Ovulation can occur even if a menstrual period has not occurred
- Some women can feel a bit of pain or aching, near the ovaries during ovulation. This is called "mittleschmerz"
- If an egg is not fertilized, it disintegrates and is absorbed into the uterine lining
- Sperm can live in a woman's body up to 5 days after intercourse, though more often 2 days.
- Pregnancy is most likely if intercourse occurs anywhere from 3 days before ovulation until 2-3 days after ovulation.
- A nomal menstrual cycle that is associated with normal ovulation and has a regular length (average 21-35 days) is also called "eumenorrhea"
The uterine cycle involves changes in the uterus. It occurs in tandem with the ovarian cycle, and is divided into two phases:
- The proliferative phase (days 5 through 14) is the time after menstruation and before the next ovulation, when the lining of the uterus increases rapidly in thickness and the uterine glands multiply and grow.
- The secretory phase (days 14 through 28) is the time after ovulation. When an egg is not fertilized, the corpus luteum gradually disappears, estrogen and progesterone (hormone) levels drop, and the thickened uterine lining is shed. This is your menses (your period).
A woman's monthly cycle is measured from the first day of her menstrual period until the first day of her next period. On average, a woman's cycle normally is between 28-32 days, but some women may have much shorter cycles or much longer ones. The cycle length depends all on when you ovulate. Ovulation can occur at various times during a cycle, and may occur on a different day each month.
Ovulation can be calculated by starting with the day the last menstrual period (LMP) starts or by calculating 12-16 days from the next expected period. Most women ovulate anywhere between Day 11 - Day 21 of their cycle, counting from the first day of the LMP.
The "fertile time" of a woman's cycle, is the time when sexual intercourse can get you pregnant, it's also called the "fertile window". The fertile window about 5-6 days long and it includes the day of ovulation and the 4-5 days prior to that day.
Tracking ovulation and the menstrual cycle can help a woman get a better idea of when pregnancy can and can not occur during her monthly cycle. Fertility Awareness is one way to track when ovulation occurs and it includes studying the changes in cervical mucus and using a basal thermometer. Cervical fluid will change to a wet, slippery substance that resembles "egg whites" just before ovulation occurs and until ovulation is over. A thermometer helps track a body temperature rise, which signals that ovulation has just occurred. Another way to track ovulation is through ovulation kits and fertility monitors. Once ovulation has occurred, there is nothing you can do to increase your chances of pregnancy. Your next step is to begin watching for early pregnancy symptoms.