What Is a Luteal Phase Defect?

A menstrual cycle—with its rises, falls, and pulses of hormones—orchestrate egg development and the thickening and transformation of the uterine lining, both of which are necessary to get pregnant. These rises and falls are categorized into two phases that divide a menstrual cycle: the follicular phase (prior to ovulation; estrogen dominant) and the luteal phase (after ovulation; progesterone dominant).

The follicular phase marks the first half of the menstrual cycle, from your first full day of menstrual flow to ovulation, around cycle day 14 in a 28-day-cycle. During this time, rising follicle stimulating hormone (FSH) and luteinizing hormone (LH) (and a lot of cellular energy) help the egg mature and develop properly. During this phase, the dominant follicle grows and its many granulosa cells rapidly increase in number. The granulosa cells release estrogen which acts on the endometrium to thicken.

The luteal phase is the second half of a menstrual cycle, from ovulation until the day before your next period starts, roughly day 15 to 28 in a 28-day-cycle. After the nurturing follicle cells release the egg during ovulation, the remaining shell of follicle cells transform into the corpus luteum. Its main function is to secrete progesterone needed by the uterus to help transform the thickened endometrium (which occurred from the rising estrogen levels of the follicular phase), creating a cushy, fertile ground for a fertilized egg.

What is luteal phase deficiency?

A luteal phase deficiency or luteal phase defect (LPD) happens when progesterone levels don’t peak high enough and long enough in the luteal phase to support proper transformation of the uterine lining. This step is essential for a fertilized egg to implant successfully. What is considered a short luteal phase is subjective, but generally thought to be 10 days or less from ovulation to menstruation. Another common sign os LPD is spotting for several days prior to your full flow menstruation.

What causes a luteal phase defect?

A luteal phase that prepares a healthy, thickened lining relies on having a high peak and duration of progesterone. This rise in progesterone is achieved by a healthy and strong corpus luteum, which is a product of properly matured ovarian follicles. The corpus luteum is maintained by pulsatile LH hormones released by your pituitary. There may be other important supporting hormones to help keep the corpus luteum viable and producing progesterone. Anything that messes with these factors, can cause LPD, including:

Low antioxidants

Increased oxidative stress, caused by higher levels of reactive oxygen species (ROS), can damage follicle cells and your eggs. We make ROS all the time as part of regular cell metabolism, but we also subject our bodies to extra ROS when we inhale or ingest unhealthy particles (air pollution, smoke) and foods (fried or charred foods), as well as from over-eating, inflammation and infections.

The cells of ovarian follicles (granulosa cells) contain antioxidants such as Vitamin C, Vitamin E, Glutathione and Melatonin. They help protect follicles and eggs from damage and ensure follicle quality for better progesterone release once the follicle develops into the corpus luteum. If your body is battling too much ROS without ample antioxidants to help, those follicles and eggs are vulnerable to damage. Damaged follicle cells can affect the quality of the corpus luteum and lower progesterone.

Low melatonin

Melatonin, the hormone that regulates your sleep-wake cycle, has many other functions. Melatonin regulates your body’s production of LH, and the release of LH follows a circadian schedule. Because Melatonin is closely linked with the function of the ovaries, those with irregular sleep schedules (like those who work in shifts), or those who get less than six hours of sleep per night have an increased likelihood of a shorter menstrual cycle. Melatonin is also an antioxidant that your body uses before ovulation to help protect your eggs in those final stages before the egg is released.

Low energy availability

Having a major caloric deficit from overexercising and/or undereating reduces the amount of energy in the body. When there’s a limited amount of energy in the body, the body directs it away from reproductive processes and puts it towards critical systems for survival. One of the effects of this is LPD which can then progress to long, irregular cycles or having menstrual periods stop altogether.

One controlled study took people with a healthy BMI (between 19 and 25kg/m²) and no menstrual dysfunction and had them follow a diet and exercise plan that reduced their energy availability over the course of three menstrual cycles. Following this diet significantly shortened the luteal phase from 12 .1 days to 9.6 days. The takeaway? Low energy availability decreased the pulse frequency of Luteinizing Hormone (LH) by almost 50 percent and having a lower LH pulse frequency significantly increased the likelihood of having LPD.

Phthalates and Bisphenol A

Phthalates are a group of chemicals and plasticizers found in fragrances, body products and plastics. Bisphenol A is used in plastics but is also found on thermal receipt paper and in the lining of canned foods. Both Phthalates and Bisphenol A have been linked to shorter luteal phases. Bisphenols can cause DNA damage in eggs, interfere with egg development and have been associated with reproductive disorders like endometriosis and fibroids.

How do I know if I have a luteal phase defect?

Tracking your cycle may give you a hint that you have a luteal phase defect. Count the number of days from ovulation until the day before your next period starts. If the number of days is less than 11, the luteal phase is likely too short. The diagnosis of LPD is subjective and not all fertility specialists feel that it’s a well-established diagnosis. Often more objective testing is suggested, like tracking your blood progesterone levels after ovulation (in the luteal phase).

How can I avoid luteal phase defect?

The best way to naturally increase your luteal progesterone is to protect those ovarian follicles while giving them all the nutrition they need.

Increase your luteal progesterone through supplementation

• Vitamin C and Vitamin E: In a study of people who had low peak progesterone levels in the luteal phase, supplementing with 750 mg of Vitamin C daily over three cycles led to significantly greater luteal progesterone levels in addition to greater estrogen levels. Fifty-three percent of participants who took Vitamin C had an improvement in progesterone. Like Vitamin C, Vitamin E is an antioxidant found in the ovaries and helps protect your follicles and eggs. It can also help thicken the uterine lining, though it doesn’t directly affect progesterone levels. Instead, it helps modify inflammation and blood flow and pairs particularly well with Vitamin C, since Vitamin C can recycle and reactivate Vitamin E, making these two antioxidant vitamins partners in defense.

• N-acetyl Cysteine (NAC): NAC is an antioxidant used to make glutathione in the body, another powerful antioxidant. When taken as a supplement at doses of 1200 mg daily, it’s been shown to improve the growth and maturation of ovarian follicles in people with Polycystic Ovary Syndrome (PCOS), in addition to significantly increasing thickness of the uterine lining.

• Melatonin: Melatonin plays a role in follicle and egg quality, indirectly affects progesterone production, and can affect menstrual cycle regularity.

Increase your luteal progesterone through lifestyle changes

• Get enough sleep: Aim for seven to eight hours of sleep each night. If you work shifts, nights or irregular hours, try taking a Melatonin supplement to regulate your sleep-wake cycles or use a light therapy lamp for 15 minutes upon waking to help regulate your circadian rhythm.

• Avoid Bisphenols and Phthalates: Although it’s impossible in North American living to avoid all plastics and fragrances all the time, you can actively decrease your exposure to chemicals such as Bisphenol A and Phthalates by replacing body and hygiene products with fragrance-free or phthalate-free products. Try switching out plastic water bottles and food containers with glass, stainless steel or food-grade silicone bottles and containers.

• Ensure adequate caloric intake and avoid over-exercising: If you currently have a body-mass index (BMI) less than 18.5kg/m² and you have irregular cycles, you’ll want to ensure you’re eating enough calories each day (about 1700-2100 calories per day depending on how physically active you are). You’ll also want to tone down any cardiovascular exercise and focus on strengthening exercises and yoga. Athletes and long-distance runners should also consider scaling back on training. Cap your running at 30 km per week, and no longer than 60 minutes per day. You can supplement your non-cardio/run days with yoga, barre, or other strengthening activities. All physical activity should be followed by adequate calories and protein to prevent muscle wasting and excessive body fat loss. Changing eating and exercise patterns can be really challenging and you’ll want to approach this in a healthy way. Don’t be afraid to reach out to a nutritionist or dietary counsellor for support, especially if you suspect you have an unhealthy relationship with food or if you’ve ever experienced disordered eating.

• Boost your egg support with antioxidants: A luteal phase deficiency is just one factor that can cause infertility. You can support your luteal phase and progesterone production by adopting a healthy lifestyle that encourages good egg quality and hormone regulation. For an extra boost of egg quality support, consider supplementing with ovarian antioxidants such as Vitamin C, Vitamin E, and NAC. Bird&Be Powers for Females contains 100 mg Vitamin C, your daily recommended 25 IU of Vitamin E, and 500 mg of NAC to protect your follicles and support a healthy corpus luteum each cycle.