Learn what ovulation and fertilization really mean, and how you can tell if you are ovulating.
Getting pregnant is not always as easy as it is made to look on television and in the media. For some women, it’s a stressful and taxing battle to conceive. Many of my patients trying to get pregnant often ask me “How do I know when I’m ovulating?” So I am devoting this article to this topic--ovulation.
What is Ovulation?
Unlike men who produce sperm their entire lives, women are born with a preset number of eggs from the get-go. Once puberty hits, an egg is released from its follicle in the ovary with each menstrual cycle-- a process called ovulation.
Ovulation is induced by a special chemical called “LH” (or Leutinizing Hormone) which is released from the pituitary gland in the brain. This rise in LH is often referred to as the LH surge, which stimulates the release of the egg from its follicle (ovulation) in the ovary 34 to 36 hours later.
If this egg is not fertilized with a sperm, it simply degenerates and dissolves.
What is Fertilization?
In order for an egg to become fertilized, a sperm must travel from the vagina into the cervix, swim across the cervical mucus, and then finally dive into the fallopian tube where that egg that just ovulated 12 to 24 hours prior is located.
Once that egg is fertilized, it starts to migrate down the fallopian tube and into the uterus, where it begins to implant (about three to four days later) into the lining of the uterus, called the endometrium.
How Do You Know When You Are Ovulating?
There are five main ways a woman can tell whether or not she is ovulating.
1. Timing: The average menstrual cycle lasts about 28 days--though the normal range is between 21 and 35 days. Keeping track of your cycles on a calendar can help determine when ovulation occurs. Ovulation occurs somewhere between day 13 and 15 for those on a 28 day cycle, and it typically occurs somewhere between day 13 and 20 for those whose cycles range between 27 to 34 days.
2. Cervical mucus: Some women experience an increase in their vaginal discharge during ovulation. That is typically produced by the growing follicle in the ovary that produces estrogen as it grows. This increase in estrogen hormone levels causes an increase in the cervical mucus in turn -- it is thinner, clear, and elastic.
3. Pelvic pain: Another indication that you may be ovulating is a mid-cycle pain that some women may experience on one side of the pelvis, lasting 1-2 days, that is caused by stretching nerve fibers as the egg “breaks out” of the follicle within the ovary.
4. Ovulation kits: Various over-the-counter ovulation kits include urine dip sticks that detect the LH surge when it occurs. Once the sticks show this increase in LH levels, it’s an indication that ovulation will typically occur somewhere between 12 and 44 hours after. Urine dip stick testing should begin two days prior to the expected day of ovulation.
5. Basal body temperatures: Elevated progesterone levels during ovulation causes the body temperature to rise at least 0.5 degrees Fahrenheit. Ovulation typically results in an elevated temperature for at least several days. Therefore, one way to find out whether you are ovulating is to take your first morning temperature after your period is over. That is best if done before getting out of bed first thing in the morning.
Other Tricks to Predict Ovulation
There are also other various medical tricks used to predict ovulation, including pelvic ultrasounds and hormonal blood tests. But these are typically performed by an infertility specialist. If your periods are irregular and you are not able to determine when you ovulate, your physician can do a blood test to further investigate possible causes of anovulation, or lack of ovulation. Some common causes are polycystic ovarian syndrome (PCOS), thyroid disorders, and eating disorders or extreme exercise.