YouTube has many videos discussing the importance of using probiotics to support
fertility. Of course, many of these are from companies who are selling probiotics. Is
there any evidence to support these claims? Should you be using probiotics? Stay tuned.
What
are probiotics? Simple. Probiotics are live microorganisms such as bacteria and yeast.
These bacteria are either eaten or in some cases may be inserted into a body cavity. For fertility,
for example, some recommend putting probiotic bacteria directly into the vagina. I know what you
are thinking. Bacteria cause infections. Why would anybody want to put bacteria into the vagina?
Here is the logic. It turns out that human beings are covered in bacteria inside and out. There is
bacteria in your mouth, stomach and intestines. There are also bacteria that are normally in the
vagina and in the uterus. All of the bacteria in a given portion of the body is called a microbiome.
Many types of bacteria appear to be essential for normal health. We will call these “good”
bacteria. In the vagina, for example, a group of bacteria called lactobacilli
are thought to be good bacteria. People who have low levels of these bacteria,
may be predisposed to vaginal infections from other “bad” bacteria. This is known
as bacterial vaginosis. Some studies have tried giving people probiotics with lactobacilli to
prevent or treat bacterial vaginosis. The results have been mixed at best.
A number of studies have tried to determine whether people with bacterial vaginosis are
at increased risk of infertility. A few small studies found that bacterial vaginosis is more
commonly found in infertility patients than in pregnant patients. Another few
studies found it was more common in people with tubal infertility than
with other causes for infertility. However, at least six studies found no difference in
IVF pregnancy rates between people with bacterial vaginosis and those without.
Here is an important point, just because bacterial vaginosis is found more commonly in
people with infertility does NOT mean that is the cause of their infertility. But lets
assume that it is the cause. Is there any evidence that probiotics can improve natural
fertility? After an extensive search, I was not able to find any studies which
looked at the impact of probiotics on natural pregnancy rates or miscarriage rates. Therefore,
any practitioner, website, post or video that says that probiotics will improve
your natural fertility are doing so without any evidence to back them.
Could probiotics help improve IVF success rates? There have been several studies looking at
this. However, no studies so far have found a higher IVF pregnancy rate by using probiotics.
None. Why not? Why didnt these studies improve IVF success rates?
A very interesting study was just presented at the annual meeting of the European Society
of Human Reproduction and Embryology. In this study, researchers recruited 74 IVF
patients who had a low amount of the good type of vaginal bacteria, lactobacillus
These people were randomly assigned either to receive vaginal probiotic capsules or a
placebo without any probiotic. When they checked the levels of vaginal bacteria after treatment,
they found something surprising. The patients who took the placebo had a 40% increase in the
amount of good bacteria. In those taking the probiotic, there was only a 29% increase in
good bacteria. This is important because it indicates that over time the vaginal
microbiome can improve on its own without any help. If also demonstrates that probiotics may
fail to increase IVF success rates because they fail to improve the vaginal microbiome.
Our infertility bottom line is this: At this point, there is no evidence that demonstrates
that probiotics can improve fertility or decrease miscarriage risk. There is no evidence that it can
improve IVF success rate. Other than the expense, however, there does not appear to be much harm