The supplement world can be a mine field when you’re trying to cover all your bases. More is not always better, and it’s important to understand why you’re taking something. While supplements can be an important addition to your preconception care, there are supplements which are associated with fertility that actually have a negative impact on conception.

Two to consider adding

Vitamin D

D is for Deficient

According to the Australian Government, 1 in 4 Australian women is deficient in Vitamin D. Deficiency is defined as having a Vitamin D blood result of less than 50nmol/L, a level considered to be the minimum for functional bone health. For functional reproductive health, we need a level closer to 70nmol/L and for optimal reproductive functioning we want to see numbers closer to 100-200nmol/L. Given these numbers, we can consider that 25% by the Australian Government to be vastly under estimated.

Vitamin D and reproduction

Vitamin D plays a role in hormone production and cycle regulation. Research has shown high levels of vitamin D to:

have beneficial effects on metabolic and hormonal parameters of PCOS
positively impact hormonal parameters of endometriosis.
have a correlation with positive IVF outcomes, in terms of fertilisation and implantation, although less likely to play a role in egg quality. 2012 study showed less likely to be about embryo quality.

Who should be considering supplementation?

Implantation or fertlization failure
Our main source is UV light, so anyone with low exposure to sunlight. Research has shown shift workers and people working indoors are more likely to be deficient.
Women with darker skin tones. Melanin protects the skin from UV rays, meaning the body synthesises vitamin D more slowly than women with less melanin.
Women with larger bodies are more likely to be deficient.

Take it right

Morning or night, with or without food, vitamin D isn’t overly fussy. It is fat soluble so while it is better absorbed with food, if you’re just topping up your levels you don’t have to get your knickers in a twist over it. Dosage depends on the individual. Don’t DIY, invest in a few minutes to speak with a professional and look for a clinician or practitioner only brand.

Vitamin E

Antioxidant power

Vitamin E is fat soluble vitamin which acts as an antioxidant, and is positively correlated with egg quality. I have written a lot about antioxidants before. I love them. They’re fantastic for the health of egg and sperm and you can read a whole lot about that over here.

Endometrial lining

The lining of the uterus should be at least 6mm thick to support implantation.

A 2017 study looked at 40 women with recurrent implantation failure. For 12 weeks, half the group was supplemented with 400IU per day of vitamin E, while a control group took a placebo. At the end of the 12 week period, researchers found that the supplementation group had on average, a significantly thicker endometrial lining than the control group.

Who does it suit?

Women concerned with the quality of their eggs, or women in their mid-late 30’s and beyond.
Women who have been told they have an endometrial lining of 6mm or less at mid cycle.
Women prescribed Clomid, due to its thinning effect on the endometrium.

Two to drop

L-Arginine

L-Arginine is an amino acid which has been shown to negatively impact egg quality.

Whats the confusion?

L-arginine increases a substance called nitric oxide, which is a powerful vasodilator (consider this foreshadowing). Vasodilation means opening up of the blood vessels, which allows for more blood flow. Increased blood flow means more nutrient delivery and hormone transport.

In 1999, researchers hypothesised that supplementation with L-arginine would improve follicular growth, egg quality and quantity, and endometrial lining through increased blood flow to the uterus and the ovaries.

The results were promising. IVF “poor responders” supplemented with arginine had fewer cancelled cycles and an overall higher egg yield.

Further research in 2002 looked at groups with tubal infertility with similar findings predicted. Unexpectedly, women supplementing with arginine saw a decrease in embryo quality on observation, and a statistically lower chance of pregnancy. These researchers demonstrated that L-arginine actually negatively impacts quality of the embryo.

Remember nitric oxide? In 2002 researchers confirmed a correlation between high nitric oxide and poor egg quality.

Who is taking it?

Even now, 20 years on from the initial study, a quick google search for ‘supplements for fertility’ will pull up L-arginine. I have worked with women who have self prescribed this one, women who have been inadvertently taking it in a protein powder and in one instance taking it as suggested by a GP.

Melatonin

Antioxidant

Melatonin is a naturally occurring hormone which acts as an antioxidant. I’ve written more about the importance of supporting our natural melatonin production here, and how melatonin acts as an antioxidant to support egg quality here.

Supporting natural production vs supplementation

When we start considering supplementation, things change. Melatonin plays an important role in regulating the menstrual cycle, so while there is a benefit to egg quality, the negative impact on cycle regulation very likely cancels that benefit out.

The exception

There’s always an exception to the rule. With melatonin supplementation, the exception is IVF, the simple reason being that in IVF the cycle is already being controlled.

In fact, it appears melatonin supplementation may has a positive impact. Researchers compared women supplemented with melatonin leading into their IVF cycle, with a group of women who did not supplement. 50% of the eggs from women in the melatonin group fertilised, compared to 23% in the control group. Women from the supplemented group were also significantly more likely to become pregnant and have a live birth.

Who should take it?

Only women going through IVF cycle with concerns about egg quality.

The takeaway

If you’re considering adding a supplement, ask yourself; is it being sold TO me, or prescribed FOR me?

Still looking for supplement advice? Take a look here.

Supplements for fertility; 2 to add and 2 to drop.