When you’re trying to get pregnant, your luteal phase -the part of your cycle that happens after ovulation- needs to be long enough for the embryo to find a nice spot in the uterus to implant itself.
But how do you make sure that it’s long enough? And what does a “long enough” luteal phase even mean?
Let’s talk about that for a minute!
What is the luteal phase?
Your menstrual cycle can be divided into two parts: the follicular phase and the luteal phase. The follicular phase starts on cycle day 1 and continues until (and including) the day of ovulation.
The luteal phase starts the day after ovulation and continues until the last day of your cycle.
The luteal phase is a crucial part of your cycle as the most important events will fall into this phase.
This is what you can (hopefully) expect- timewise:
- Day 1 of the luteal phase: Sperm and egg meet. The (fertilized) egg is now called a zygote.
- Day 1-5: the embryo keeps developing, growing, and expanding every day. On day 5 or 6, it will reach a critical milestone in its development and will now be called a blastocyst.
- Day 8-10: This is where the real magic happens. The tiny clump of cells is now ready to find a spot in your uterus to implant. And as soon as that happens; you’re officially pregnant!
- Day 10-14: As soon as the embryo has implanted, the pregnancy hormone (hCG) is secreted. It usually takes a few days before the levels are high enough to be picked up by a pregnancy test, but somewhere between day 10 and 14 of your luteal phase is when you can expect to get a positive!
What is luteal phase deficiency / short luteal phase?
As you can see by looking at the timeline, the embryo needs quite a few days before it’s ready to implant. What happens if the first 2 events went according to plan (the egg was fertilized, the fertilized egg developed properly), but then just as it was about to implant, you get your period?
Well, that’s what the short luteal phase, or luteal phase deficiency/defect, is all about. It’s what happens when your body doesn’t give your fertilized egg enough time to implant.
As most healthy embryos implant within the first 10 days from ovulation, a short luteal phase, is often defined as a luteal phase shorter than 10 days.
Which hormones are involved?
The key player of the luteal phase is the hormone progesterone. After ovulation, it is secreted by the “corpus luteum” or yellow body. This is the structure that housed the egg inside the ovaries before ovulation.
If you’re pregnant, the pregnancy hormone (hCG) communicates back to the corpus luteum that it needs more progesterone, and the corpus luteum will stay alive.
If implantation did not occur, the corpus luteum slowly starts to fade away and die, which stops the production of progesterone. And without progesterone, the uterus can’t keep the outer layer intact and it will start to shed (in other words; you get your period)
How to fix a short luteal phase
So if you need a long enough luteal phase for the embryo to implant, and progesterone makes sure your period doesn’t start yet, wouldn’t it make sense that treating with progesterone could help lengthen the luteal phase?
Yes! That’s exactly what many doctors do: they treat luteal phase defect by prescribing progesterone suppositories that you need to insert vaginally every day starting 3 days past ovulation.
But what if you want to try lengthening your luteal phase naturally, before asking your doctor for help? Are there any natural ways to boost progesterone production that can lengthen your luteal phase?
That’s what we’ll investigate in the next few sections! First up, Vitamin C.
Did you know that many women with unexplained infertility have what is called a lower antioxidant status? And vitamin C is the primary antioxidant.
There is a LOT of ascorbic acid (the fancy word for vitamin C) in the ovaries and animal studies show us that it’s primarily ascorbic acid which protects the ovarian cells from oxidative damage. And with less vitamin C, the corpus luteum -the structure that sends out progesterone telling your body to NOT start your period just yet- can break down faster too.
You see? Having enough vitamin C can very well play an important part in trying to lengthen your luteal phase!
Having enough vitamin C in the reproductive system helps support the luteal phase, embryo implantation and embryo development.
Research in favor on vitamin C:
- A small study from 1977 had women take 400 mg of ascorbic acid every day. This enhanced the ovulation-inducing effects of clomiphene (an ovulation drug) in women who weren’t ovulation regularly.
- In a Japanese study from 2003, women who were given vitamin C showed much higher progesterone levels than women who did not receive vitamin C supplements. More women also got pregnant (11% vs 25%!).
- In an IVF study, taking a vitamin C supplement was also linked to a somewhat higher pregnancy rate (24% vs 34%).
Research against vitamin C:
- A larger and high-quality study from 2001 found that supplementing with vitamin C in the luteal phase ranging from low to high doses did NOT help women get pregnant.
What it means:
The evidence that vitamin C supplementation works to lengthen your luteal phase isn’t particularly strong, especially if you’re only taking it during the luteal phase.
Having said that, taking a vitamin C supplement, a good multivitamin with vitamin C, or eating foods containing vitamin C (looking at you bell peppers) is still a good idea, especially if you start earlier in your cycle. Keep in mind that very large doses of vitamin C can be harmful, so don’t overdo it!
Selenium (Brazil nuts)
Selenium is a trace element that is essential in thyroid hormone synthesis. selenium is also a powerful antioxidant. Are you wondering which food has lots of selenium? Brazil nuts!
Research suggests that a deficiency in selenium is linked to male-factor infertility, and higher risks of pre-eclampsia and preterm labor. An association between low levels of selenium and a shorter luteal phase has also been suggested.
Selenium is an antioxidant that can help prolong the luteal phase, among other fertility-enhancing properties.
Research in favor of selenium:
- We know that progesterone should remain high enough, long enough in the luteal phase for an embryo to implant. And guess what, plasma selenium levels are correlated to (higher) luteal phase progesterone levels!
- In a large study, women who consumed twice the daily recommended amount of selenium had a 77% lower risk of luteal phase deficiency.
- And while you’re munching on Brazil nuts, you might offer it to your guy too: In a study among men, selenium supplementation was linked with a higher sperm count and quality.
What it means:
While there isn’t much high-quality research out there on whether selenium can help you get pregnant if you have a short luteal phase, the evidence we do have is encouraging. It looks like the antioxidant properties of selenium may actually help your fertility and maybe it even helps boost progesterone levels!
Vitex (or Chasteberry) is often brought up when discussing ways to boost fertility. Many women believe it can boost fertility, and some have even said it lengthens the luteal phase. But even though it’s a popular alternative medicine -mostly used for treating PMS symptoms-, very limited real evidence exists that it does any good.
To make matters worse, taking vitex actually screw with your hormone balance and your cycle, so always talk to a medical doctor before even considering it.
Too much of the hormone prolactin can set off a cascade that disrupts and suppresses sex hormones (testosterone, estrogen). Vitex decreases prolactin levels and it is said to boost sex hormone and thereby fertility. But because most studies have focused on how Vitex may decrease symptoms of PMS, very few have investigated the role of Vitex in prolonging the luteal phase. Let’s see what the science says:
Research in favor of Vitex:
- A small German study from 1993 describes 37 women with “hyperprolactinemia” (too much prolactin). Giving 20mg of daily Vitex reduced prolactin levels and prolonged the luteal phase by 5 days and normalized luteal phase progesterone levels.
- Other small studies carried out a long time ago suggest that Vitex supplementation may improve menstrual cycle stability and cyclicity in women with very irregular cycles!
Research against Vitex:
- In animal studies, supplementing mice with Vitex did not improve fertility or litter size.
- Female baboons eating lots of African black plums (a species of Vitex plant) have trouble getting pregnant because the huge spike in progesterone caused by eating the fruit acts as a contraceptive. Yep, you read that right. Baboons consuming a lot of vitex didn’t just not boost their fertility, they couldn’t get pregnant at all!
What it means:
Vitex is a popular herbal treatment used by some to treat premenstrual syndrome and high prolactin levels (hyperprolactinaemia). In women who have very high prolactin levels supplementation could restore the luteal phase to an acceptable length. But very little is known about vitex and fertility.
The jury is still out as there’s simply very little (convincing) evidence supporting vitex as a fertility booster and luteal phase support.
Anecdotally, I’ve heard of many women who started taking Vitex hoping it would improve fertility, only to find that it completely messed up their cycle, for example by delaying ovulation for days or even weeks! There are also side-effects to keep in mind: ranging from nausea to adverse interactions with other medications (birth control, hormone replacement therapy etc.), so definitely talk to your healthcare provider before considering Vitex.
So what should you do?
Of the many natural remedies that many say will lengthen your luteal phase, I talked about the 3 most prominent ones. You might have come across many others vitamins, herbs and remedies on your late night Google trips. But trust me when I say this: don’t believe everything you read, there’s a lot of nonsense out there, and you don’t want to be doing more harm than good. Let’s go over the 3 most popular ones one more time.
Taking a vitamin C supplement, a good multivitamin with Vitamin C, or eating foods high in vitamin C may boost fertility through its antioxidant properties. Don’t wait until the luteal phase to start, as short-term supplementation did not show any benefits.
There isn’t a lot of hard evidence, but the antioxidant properties of the essential trace element selenium may actually help you boost progesterone and lengthen the luteal phase and could even improve sperm quality. Don’t go overboard eating Brazil nuts in very high quantities (selenium is toxic at high concentrations), but there may actually be something to this!
Unless you’ve been diagnosed with very high prolactin levels (hyperprolactinaemia), I’d say there’s not nearly enough evidence to support this the use of vitex, especially considering the potential side effects. Doctors sometimes recommend AGAINST taking vitex as it may cause hormonal shifts that can disrupt your cycle, so always consult with your doctor first before taking vitex!
The easy way: multivitamins
If you don’t want to think about which individual vitamins to supplement, then the best approach is to take a (prenatal) multivitamin. Prenatals (yes, even before you’re pregnant!) are really important because they can boost fertility for many reasons, including boosting egg quality. I’m partial to this Smarty pants multivitamin (affiliate link). Not only does it does it taste yummy because it’s a gummy, it also contains Vitamin C and Selenium, as well as other important fertility-boosting things such as folate and Omega-3 fatty acids.
Perhaps the most important advice I can give you is that if you notice your luteal phase is consistently too short (less than 10 days); talk to your doctor. They might recommend starting progesterone suppositories, which have a good track record of lengthening the luteal phase as well as boosting progesterone levels.
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