How to Increase Your Luteal Phase Naturally

A woman’s menstrual cycle consists of two phases: the follicular phase, and the luteal phase. The follicular phase starts on the first day of your period until ovulation.

The luteal phase starts after ovulation and ends the day before your period. Importantly, it is during this phase that the uterine lining (endometrium) transforms and thickens to allow a fertilised egg (embryo) to implant. Therefore any disruption to this process can affect a woman’s fecundability.

Women trying to get regular periods naturally will sometimes discover a shorter than normal luteal phase.

How Long is the Luteal Phase

Generally speaking, the luteal phase lasts between 11 to 17 days (mean 14.2 days).

However it is not uncommon for women to experience a short luteal phase (≤ 8 days). In fact, 18% of women experience a shorter than normal luteal phase (≤ 11 days) occasionally, but only 3% have recurring episodes.

Does a Short Luteal Phase Cause Infertility

A short luteal phase indicates your body did not produce enough progesterone that cycle. However a short luteal phase does not necessarily mean you are infertile. This is because successful embryo implantation produces human chronic gonadotrophin (hCG) which sustains corpus luteum and progesterone production until the 8^th week of pregnancy.

In fact, the only thing experts agree on so far is that an insufficiently developed endometrium will cause embryo implantation failure, and that the minimum number of luteal phase days required for proper endometrial development varies greatly. This is why studies to date which investigated the impact of luteal phase lengths, on IVF outcomes, found no difference in live birth rates.

Causes of a Short Luteal Phase

The most obvious reason for a short luteal phase is a failure of the corpus luteum to secrete enough progesterone. This can happen when a smaller than normal follicle is developed during the follicular phase of the cycle which results in a smaller than normal corpus luteum that naturally secretes less progesterone and has a shorter lifespan. The reason this happens (cause vs. effect) is less obvious and usually requires tests to rule out known causes of short luteal phase.

Known causes of short luteal phase include:

• Stress
• Dieting
• Excessive exercise
• Endometriosis
• Polycystic Ovarian Syndrome
• Premenstrual Syndrome
• Thyroid disorders
• Hyperprolactinema
• Anorexia

Symptoms of a Short Luteal Phase

• Shorter than normal menstrual cycles
• Miscarriage (chemical pregnancies)

Although low progesterone levels, on day 7 after ovulation (or cycle day 21) may indicate a short luteal phase, there is no clearly defined minimum level required due to a lack of quality evidence.

Natural Short Luteal Phase Treatments

According to the latest research, the following natural treatments may increase your luteal phase:

• Ascorbic acid
• Vitamin E
• Vitamin D
• Folate
• Antioxidants
• Vegetable Protein

Ascorbic acid

Ascorbic acid (also known as Vitamin C) is a natural water-soluble vitamin that is not stored by your body. This essential vitamin and potent antioxidant can significantly increase progesterone levels (and estradiol) in women with luteal phase defect.

In one study, women taking vitamin C supplements (750 mg/day) for just 3 weeks, had significantly improved progesterone levels in 53% (40/76) of women. These women then continued supplementation for 6 months, whilst trying to conceive naturally. Overall, 25% (19/76) became pregnant compared to only 11% (5/46) in the control group.

In a more recent study, ascorbic acid levels among normal women were found to be inversely associated with BMI and adiposity (i.e. waist-to-hip ratio). This means overweight and obese women are more likely to be deficient in vitamin C.

Foods rich in vitamin C include guavas, bell peppers (capsicum), kiwifruit, strawberries, oranges, papaya, broccoli, tomato, snow peas and brussel sprouts.

Interestingly, the Recommended Dietary Allowance (supplementation) of vitamin C is 75 mg, or 110 mg for smokers, not including food sources. The Tolerable Upper Intake Level for vitamin C is 2000 mg however absorption of vitamin C decreases significantly above 1000 mg as the body’s tissues become saturated.

Vitamin E

Vitamin E is an essential fat-soluble vitamin, which can be stored in the body’s fatty tissue and liver. This natural antioxidant has several forms, however only α-tocopherol can reverse vitamin E deficiency.

Interestingly, α-tocopherol levels are significantly higher in the follicular phase, and lower in the luteal phase among healthy women. This suggests the body’s metabolism of vitamin E changes across the menstrual cycle.

Studies show that α-tocopherol levels increase moderately with age among health women. While in adolescent girls, α-tocopherol levels decease linearly according to BMI.

Foods rich in vitamin E include sunflower seeds, almonds, hazelnuts, pine nuts, peanuts, brazil nuts, avocados, spinach, kiwi fruit and broccoli.

This suggests only sunflower seeds, almonds and hazelnuts are most likely to improve your α-tocopherol levels and not interfere with ovulation.

Alternatively, the Recommended Dietary Allowance (supplementation) of vitamin E for women trying to conceive is 15 mg, not including food sources.

Vitamin D

Vitamin D (calciferol) is an essential fat-soluble vitamin often lacking in the general population (<20ng/ml). Crucially researchers define vitamin D as a steroid hormone with progesterone-like activity.

In fact, studies show vitamin D deficiency decreases both estrogen and progesterone levels which significantly increases the risk of short luteal phases and longer menstrual cycles. However researchers are yet to confirm what exactly causes these 2 different outcomes among vitamin D deficient women.

Further studies also show that vitamin D and progesterone mutually support one another during endometrial transformation (i.e. receptivity), embryo implantation and pregnancy.

Although vitamin D is primarily obtained by sun exposure, vitamin D is also found in some foods such as fish, beef liver and specially fortified dairy products.

Folate

Folate is a natural water-soluble form of vitamin B9. This means it is not stored in the body and must come from your daily diet. However daily intake of vitamin B9 is low among the general population.

Folate plays several roles in the human body predominately via the one-carbon metabolism pathway. One key role involves regulating homocysteine levels which is elevated among many female specific disorders.

Interestingly, low levels of folate (21.2-41.4 nmol/L) within the normal range (21.2-78.5 nmol/L) is significantly associated with decreased levels of progesterone, during the luteal phase, in otherwise healthy ovulatory women according to one study.

Further statistical analysis by the authors revealed that for every 1 nmol/L increase in folate levels, women’s luteal phase progesterone levels increased by 1%.

This finding correlated directly with improving homocysteine levels, from 11.2 to 2.7 μmol/L, which is still considered within normal range (<13 μmol/L).

Foods rich in folate include green soybeans, beef liver, lentils, asparagus, spinach, broccoli, avocados, mangos, lettuce and kidney beans.

The Recommended Dietary Allowance (supplementation) of folate for women trying to conceive is 500 mcg, not including food sources. However your Doctor may recommend up to 1000 mcg (Tolerable Upper Intake Level) depending on your individual circumstances.

Antioxidants

Antioxidants are substances that protect cells from damage caused by free radicals. There are hundreds, if not thousands, of different substances that act as antioxidants.

However, this does not mean they all behave the same and are interchangeable. Each antioxidant has a unique chemical structure, behaviour and biological properties.

For this reason, combinations of antioxidants (or substances) is sometimes more effective than the individual substances on their own.

One such combination, marketed as a supplement to optimise female fertility and reproductive health, includes chasteberry, green tea extracts, L-arginine, vitamin E, vitamin B6, vitamin B12, folate, iron, magnesium, zinc and selenium.

In a 3 month placebo controlled trial, this combination restored normal cycle lengths and raised mid-luteal progesterone levels, from 8.2 to 10.4 ng/mL, among women who had unsuccesfully tried to conceive, between 6 to 36 months, prior to the trial.

This lead to a higher pregnancy rate in the treatment group versus the placebo group (26% vs. 10%) after only 3 months.

However the diverse range of women and variety of antioxidants used in this trial make any definitive conclusions difficult.

However, they do not treat the cause of the condition, hence why only 32% (17/54) of women were pregnant after 6 months of treatment.

Foods rich in antioxidants include walnuts, blackberries, blueberries, pomegranates, goji berries, artichokes, raspberries, plums, cauliflower and strawberries.

Vegetable Protein

A study in 2008, evaluating the dietary intake of 18,555 women trying to conceive, was the first to report that the consumption of vegetable protein significantly lowered the risk of ovulatory infertility.

A more detailed study published in 2021 using a new group of women confirmed the original findings. It also reported that women with low intake of vegetable protein (16.4 ±4.4 g/day) had significantly reduced levels of progesterone (-18%) during the luteal phase.

Further statistical analysis according to individual food types revealed that the intake of legumes, was associated with higher progesterone levels (22.3%), compared to no intake.

This suggests boosting your vegetable protein levels to at least 21.0 ±4.7 grams with legumes could significantly increase your progesterone levels.

A Tip From Fertility Science

Your luteal phase is intrinsically connected to your follicular phase. Try to minimise any stress, excess exercise or dieting during your whole cycle. Not just in the second half.

At the same time, eating the right kind of foods can definitely help lengthen your luteal phase.

The best food types to increase your luteal phase are:

• Berries
• Nuts
• Green vegetables
• Legumes

We know changing food habits is not easy. To make this worse, consciously avoiding certain foods (cognitive dietary restraint) is also stressful on the body and will lead to a shortened luteal phase. Try to make small progressive changes and don’t criticize yourself.

Keep in mind that consecutive (and recurring) short luteal phases are not normal if you are otherwise happy and healthy. If this applies to you, please speak to your Doctor and get checked out for peace of mind.

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