What Is the Luteal Phase?

One of the four stages of a monthly menstrual cycle, the luteal phase is often glossed over in the lay person’s understanding of fertility and hormone health, coming just as it does after the big mid-cycle event of ovulation. But biologically, it’s a critical time between a mature egg being released from the ovary and menstruation. Essentially, the luteal stage is the window of time in which the body’s hormone balance must be just so to optimize health, including fertility. Here’s everything you need to know about this part of your cycle.

A woman’s monthly cycle has four parts: menstrual, follicular, ovulation and luteal phases. The ovaries make eggs, and the area around the developing egg is called the follicle. Ovulation occurs when the follicle gets a hit of a hormone from the pituitary gland called LH, or luteinizing hormone and “that's how ovulation predictor kits like First Response work, measuring the surge of LH,” explains Mary Jane Minkin, OB/GYN and clinical professor at Yale University School of Medicine. Next the egg gets released, and the area from which the egg developed becomes the corpus luteum. This marks the beginning of the luteal phase, which typically lasts for 10 to 14 days. During this time, the corpus luteum starts producing progesterone, a hormone that causes the uterine lining to get thicker, i.e. more suitable for a fertilized egg to implant. If a fertilized egg implants in the wall of the uterus, the uterus becomes a womb with a fetus. If a fertilized egg does not implant, the corpus luteum shrivels and dies, and progesterone levels drop, inducing the lining of the uterus to shed. Et voila! You have your period.

Keeping track of when you begin and end bleeding is a good start to figuring out where you are in your cycle. A period tracking app such as Clue or MyFlo can help. On average, the luteal phase begins the 10 to 14 days before you begin your period. You can also chart your temperature: in the early to mid-luteal phase, a woman’s basal body temperature jumps .5 to 1 degree higher.

Along with counting days and taking your temperature, you may be able to detect the luteal cycle by watching for physical and mood changes caused by the fluctuations of hormones being pumped out by your body. At the beginning of the phase, the influx of progesterone means you may feel a bit calmer than usual, since this hormone has a mild sedative effect. Then, toward the end of the cycle, when progesterone levels drop, you may experience the panoply of emotions and body aches associated with PMS (pre-menstrual syndrome). So now you know—thanks, luteal phase, for mood swings, irritability, headaches, fatigue, bloating and sore boobs.

The luteal phase can misfire when progesterone production drops, and it can result in a woman having difficulty becoming or staying pregnant. That’s because progesterone is essential for producing a thick ovarian lining for the fertilized egg to implant in. "If women do seem to have a history of very early miscarriages, so-called luteal phase insufficiency can be happening," Dr. Minkin says, "and some infertility docs will prescribe additional progesterone." Health conditions such as endometriosis, thyroid disorder, polycystic ovarian syndrome, obesity, extreme exercise, anorexia and stress can all increase the risk of a luteal phase defect.

It’s true that traditionally, a deep dive into understanding the menstrual cycle has been a dominated by fertility-minded people. And for sure, it’s an important element in successful reproduction. But in recent years, increased attention to overall wellness, specifically the trending topic of mindful menstruation, has made it worth taking another look at what’s going on during our cycles. For example, Flo Living, a company started by Alisa Vitti, an alternative health and wellness guru, aims to educate women on lifestyle and dietary changes that complement and improve their bodies’ natural rhythms. For example, she recommends women eat special foods during the luteal phase, like complex carbohydrates such as brown rice, instead of giving in to cravings for sugar. Spices (cinnamon) and micro-nutrients (chromium) are also touted as creating a more stable blood sugar (and hence, fewer energy lags) during this time.

Ask your OB-GYN about any hormonal issues you’re having, and consult a fertility doctor if you are having trouble conceiving—or want to make sure that you’re optimally healthy for pregnancy. Consider a concurrent visit to a naturopath, whose natural, herbal and lifestyle recommendations can be used in concert with a fertility doctor’s. And good news for everyone with a luteal phase—physicians, naturopaths and pretty much everyone with an opinion supports getting at least eight hours of sleep during this time in the cycle. So there, busy schedule—sorry for the early bedtime, but we’ve got to take care of our luteal phase health.