The Fertile Cycle

Get Pregnant: Your Menstrual Cycle and Fertility

Also see:
Ovulation and Fertility Definitions

Your Cycle and Ovulation Prediction

The menstrual cycle is divided into two parts: pre-ovulation and post-ovulation. The ovarian cycle refers to the cyclical development and expelling of the egg from the ovary. Though the length and regularity of a menstrual cycle may differ, the average duration of a complete menstrual cycle is 28 days (though healthy cycles can run from 21-36 days). Below you will find an overview of a typical menstrual cycle with an image map based on a 28 day cycle length. "Day 1" of the menstrual cycle is the day bleeding begins. Bleeding - or "menstrual flow" - lasts about three to five days.

By the seventh day of the cycle, eggs in the ovaries begin to ripen due to various hormonal changes. Between the seventh and the eleventh days, the lining of the uterus begins to thicken and it is possible to observe changes in the presence and consistency of cervical fluids. After the eleventh day, luteinizing hormone causes the egg that is most ripe to be released from the ovary and begin its travel down the fallopian tubes to the uterus. For women with a 28-day cycle, ovulation (the release of the egg) should take place on about the 14th Day - or the very middle - of the menstrual cycle.

The period after ovulation is called the luteal phase, and it is marked by a salient increase in body temperature. Following ovulation, the egg travels the fallopian tube toward the uterus. If the egg is fertilized by a sperm (conception), then "implantation" should take place in the uterus (if implantation takes place outside the womb, this is an ectopic pregnancy. Ectopic pregnancy can occur in several places - but the most common is in the fallopian tube). Pregnancy begins if "implantation" occurs. If the egg is not fertilized, it will "expire" in about 24 hours.

Without fertilization, levels of certain hormones will decrease, causing the lining of the uterus to break down and shed - otherwise known as menstruation, or a woman's "period". The first day of bleeding is "Day 1" of the next menstrual cycle.

The first part of the cycle, from menstruation to ovulation, may vary from 14 to 20 days in length. The length of the pre-ovulation phase is often different from one woman to another - but it can also differ from month to month for an individual. It is during first part of the cycle that fertilization can occur. Of course, regular menstrual patterns can be altered by illness, insomnia, stress, physical exertion, and physical and emotional changes.

The luteal phase, or post-ovulation (from ovulation to menstruation), is generally the same length for most women - averaging about 14 days. As a rule, the egg is released 10 to 16 days before menstruation, or the start of the next menstrual cycle.

Fertility Dynamics

A woman's fertile period during her menstrual cycle, on average, lasts about 7 days. The most fertile period consists of the few days before ovulation. There are a number of reasons why this is the most fertile time. First of all, the amount of cervical fluid (cervical mucus, CM) increases and the consistency of the mucus changes substantially (from being sticky and cloudy to becoming transparent, white, and slippery). The purpose of this change is to create a healthy medium for the sperm to survive and travel in. Given a fertile environment, sperm can live several days. (FertileCM is a product designed to increase the quantity and quality of cervical mucus; additionally, Pre-Seed is a sperm-friendly lubricant that can be used while trying to conceive.) The egg, on the other hand, can live only 24 hours - so timing is important. At the moment of ovulation, the body temperature begins to rise to create a warmer, more hospitable environment for a fertilized egg. Also, the cervix will start to rise, soften, and begin to open up.

Hormones and Ovulation: The Release of the Egg
Also see:
Ovulation and Fertility Definitions

During ovulation, a number of different hormonal changes take place. Early in the menstrual cycle, a hormone called Follicle Stimulating Hormone - or FSH - enables your ovaries to nurture eggs. Within the ovaries, follicles house each individual developing egg. The follicles that hold the eggs will secrete estrogen. As the menstrual cycle progresses, the follicle containing the developing egg moves toward the surface of the ovary. Immediately before ovulation, the follicle begins secreting estrogen and progesterone. Estrogen helps the uterine lining thicken and expand and increases blood flow to the uterus. Progesterone causes the glands of the uterine lining to form secretions that help nourish a fertilized egg.By definition, ovulation is the process of an ovary releasing an egg from the follicle - permitting the egg to float down the fallopian tubes. On average, the first phase of the menstrual cycle last two weeks. Directly prior to ovulation, another hormonal change takes place - the LH Surge. LH (or Luteinizing Hormone) is the hormone that actually facilitates ovulation: it causes the egg to separate from the ovarian surface. Ovulation predictor tests function by detecting this LH Surge, thus alerting the woman that ovulation is about to take place.

Once released from the ovaries (post-ovulation), the egg can survive for about 24 hours. This means that sperm (which can live several days) must be present to fertilize the egg. Following ovulation, the egg enters the fallopian tubes and continues toward the womb. Typically, conception - the uniting of the egg and the sperm - will take place in the fallopian tube, and then the fertilized egg will continue its passage to the uterus and implant in the uterine wall. For pregnancy to take place, fertilization of the egg must be followed by a successful implantation.

Following ovulation, the luteal phase begins, marked by an increase of the hormone progesterone, which strengthens the uterine lining (endometrium) and causes the body temperature to increase, facilitates changes in the cervical fluid, and alters the position of the cervix .Within 24 hours, if the egg has not been fertilized, it will simply disintegrate after reaching the uterus. Without fertilization - and implantation - the levels of others hormones will ultimately drop during the luteal phase, causing the lining of the uterus to break down and shed - referred to as menstruation, or a woman's "period".

Implantation, Pregnancy & Human Chorionic Gonadotropin

Fertilization occurs when a sperm penetrates the egg - and this typically takes place in one of the fallopian tubes. The fertilized egg (or embryo) then travels to uterus and implants in the uterine lining. At this point, the embryo and developing placenta will begin to release hCG (Human Chorionic Gonadotropin). The presence of hCG will help facilitate the continued production of progesterone - essential for a fertile, hospitable environment for the implanted embryo. The hormone hCG will increase and show up in a woman's blood and urine, making hCG a prime marker for pregnancy detection. Home pregnancy tests function by detecting hCG in a woman's urine.

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My period went from the 28 days cycle, now too the 26th day cycle, I had sex when I was fertile and three days before ovulation could I be pregnant?

hi , i have a question. I made love with my man on september, 27th during my period, and now it stopped on the 30th could i be preg.

i had my last mentration on April 6 and ended to 8 of 2012...we make love on april 12, it possible that am fertile?

Hi my period is last day on march 26 , 2012 . I want to know when ovulation is ripe and exactly which day that my husband and me have to serx and try for baby . I am sex with my husband for 3 time in a week? Let me know? We are just married for one year now

Hi, I ordered FertilAid a few days ago and just got it yesterday. My question is, if I ovulated on CD 14 and started taking it on CD 16, would it still help my body prepare for implantation between CD 21 & CD 24? Had 3 successful pregnancies before Mirena and have been TTC since 2008 with no success... Thinking possibly due to issues with uterine lining after Mirena...

Me and my husband have been trying to have a baby. Ive been tracking my ovulation with tests and i havent had a positive test then this month i had a positive test but im about 3 days from my cycle to start. is that normal. if the normal ovulation is 14 days before your cycle can i have a ovulation cycle 3-4 days before my menstruation cycle. and if i start my cycle starts could i still be pregnant? thank you very much for your help.

what should i do am having a sex 3 to 4 times in a week what should i do or eat

I have irregular periods. Normally I can bleed two weeks. This month I began to spot four about 2 days then on the third day I bleed it was not heavy. That night I had unprotected sex. At that time I was not bleeding.the next day I did have a lil blood but it was light pink. Could I be pregnant?

We are in a marrage for 9 years and we tried to have a baby but we can. when we visit the docter they say every thing is ok. what can i do now.

gud 22 and my husband is 27. I just want to knw? When will i ovulate if i had my brown spot started on the 1week of jan.2 to 8. beford having a heavy mens.. Lasted on the15th of week.i also bought a trust pill to make my cycle regular.then i wl use it for 2mnth starting frm now.when i already have a normal cycle i'll stop it to know when wl i concieve thankz a lot! Hope u myt help us...ill w8t 4 ur reply.

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By TTC veteran and mother of two, Elizabeth Andrews.