How to Determine Your Luteal Phase

The luteal phase is part of the menstrual cycle that begins at ovulation and ends the last day before your period begins. According to the book "Taking Charge of Your Fertility" by Toni Weschler, MPH, the luteal phase is typically 12 to 16 days long; if it lasts less than 10 days, a woman's ability to get pregnant can be impaired. Determining the luteal phase can be done by regular charting of your menstrual cycle, using an ovulation predictor test or by diagnostic testing.

Things You'll Need

• Basal body temperature thermometer

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Instructions

• 1

  Part of fertility awareness is recording your temperature daily before getting up.

  Learn how to chart your menstrual cycle by noting the first day of each period on your calendar, daily evaluating your cervical mucus and taking a correct basal body (waking) temperature each morning. This type of record keeping is known as a fertility awareness method (FAM) or sometimes as a symptothermal method.

• 2

  Identify the time of ovulation through charting to pinpoint the start of the luteal phase. Ovulation does not always occur on day 14 of a menstrual cycle, which averages 28 days, but can vary from 24 to 36 days. About a day after ovulation, your waking body temperature rises about one degree due to the progesterone surge, and that indicates the luteal phase is under way.

• 3

  Observe and record the changes in the quantity and consistency of the cervical fluid around your vaginal opening to determine the transition to the luteal phase. During the days around ovulation, your cervical mucus will be wet with a consistency similar to egg whites. As the luteal phase begins and progesterone increases while estrogen decreases, cervical mucus will dry up quickly, sometimes over the course of just a few hours.

• 4

  Count the days after your temperature rises and your cervical fluid decreases until your next period starts. If you establish that ovulation likely happened on day 12 of your cycle and then 14 days pass before your period begins, your luteal phase is two weeks long. Day 1 is the first day of your next period.

• 5

  Buy an ovulation predictor kit and follow instructions carefully. An ovulation predictor kit uses a urine test to identify a surge in a woman's luteinizing hormones up to 48 hours before the egg is released during ovulation. Predicting ovulation gives you a starting point for the luteal phase.

• 6

  Physicians can determine if a short luteal phase may contribute to infertility.

  Seek medical help if you try a fertility awareness method or an ovulation predictor kit to determine your luteal phase and those results lead you to believe that a short luteal phase (also called a luteal phase defect) is interfering with your ability to get pregnant. Diagnostic tests are available to further determine the length of your luteal phase.