How to detect ovulation
Since timing of each woman’s ovulatory period is challenging to predict, our Vermont fertility clinic relies on an ovulation calendar to determine when ovulation occurs. Most menstrual cycles of women in their 20s and 30s last (on average) are between 28 to 32 days. The first day of a cycle is defined as the first day of a menstrual period. When an egg is released from an ovary, it remains available for fertilization for about 24 hours. Sperm deposited in the vagina may survive for 3-5 days before fertilizing the released egg; therefore a woman is most fertile the 3 days leading up to the day of ovulation. If fertilization does not occur, the progesterone levels fall, and the uterine lining is shed as menstrual blood.
How an Ovulation Calendar Helps Detect Ovulation
For women with mostly regular menstrual cycles, ovulation occurs about 14 days prior to the onset of menstruation. Ovulation calendars not only track length of periods but also monitor signs that ovulation may be occurring. For example, if you are instructed to keep an ovulation calendar for the purpose of timing intercourse or an intra-uterine insemination (IUI), you should also note days when:
- Your body temperature is slightly higher than normal as progesterone release precedes release of an egg. Body temperature elevates the day after ovulation. This method of tracking ovulation can be stressful and can only tell you that you’ve ovulated after the fact. Therefore, we more commonly recommend using ovulation predictor kits which are easier to use (below).
- Your cervical mucus thickens as estrogen levels rise and becomes sticky and stretchy (called “spinnbarkeit”).
- You experience mild aches in your mid-section (not all women feel this sign of ovulation)
Ovulation Predictor Kits
Ovulation predictor kits are simple and easy to use. We often recommend buying “Clear Blue Easy” brand, and purchasing the simplest, cheapest kit you can find. Depending on the average length of your cycle, you will start testing with these kits on day 9-14 of your cycle, and test once per day. The kit works by detecting luteinizing hormone, the ovulation hormone, in your urine. Once you get a positive, your egg will release in about 24 hours, directing you to time intercourse with the positive test and the next day. This is the best test to identify in advance your fertile window.
Northeastern Reproductive Medicine is one of few fertility clinics in Vermont specializing in helping women achieve pregnancy through a variety of in-vitro fertility techniques. To learn more about fertility treatments, please call our clinic today at (802) 655-8888.
