Despite several advances in assisted reproduction, global estimates from a survey conducted in 2010 show that infertility is a still common issue affecting 48.5 million couples worldwide.  While there are several causes contributing to infertility, one often-overlooked cause is colonization of the vagina by unfriendly microbial strains like Escherichia coli (E. coli), Gardnerella vaginalis, and yeast that can impair the reproductive potential of a female.
The predominant microbe populating a healthy vagina is Lactobacillus. But when bad bugs predominate, problems like hostile cervical mucus, impaired fertilization, and infertility spawn. In such cases, re-inhabiting your vagina with probiotics containing live lactic acid bacteria may provide an alternative not only for restoring the vaginal ecosystem but also addressing infertility.
How do probiotics restore Fertility?
Probiotics can eradicate the bugs that interfere with fertility
The sperm needs to be motile and travel easily towards the egg residing in the woman’s uterine tubes to fertilize it. E. coli is one of the major bacterium retrieved from the semen samples of males with infertility. This bug sticks to the sperms and causes one sperm to adhere to another (scientifically known as agglutination), thereby restricting their motility towards the egg as tested in laboratories through experiments conducted on rodents. The experts have revealed that introducing Lactobacillus strains into the mouse’s vagina after it is housed by E. coli readily eradicates the harmful bug due to its antibacterial properties. The rodent is then able to conceive. 
Probiotics may reverse the lipopolysaccharide (LPS)-mediated inflammation
LPS is a giant molecule made up of fat (lipid) and carbohydrate (polysaccharide) found in the walls of harmful bugs like E. coli. This substance also appears to promote the fertility-impairing potential of these bacteria. LPS induces widespread inflammation, which, in turn, triggers infertility. A study conducted on mouse models showed that owing to their strong anti-inflammatory properties, lactic acid-containing probiotics can block LPS-mediated inflammation and thus, restore fertility. 
Probiotics can manipulate microbiome, which helps restore Fertility
Western lifestyle and unhealthy diet are now recognized as being one of the factors predisposing to infertility.  These factors not only disrupt the balance of a woman’s microbiome but also compromise their immunity. Owing to their knack for modifying the microbiome and optimizing the immune system, probiotics can combat the adverse effects of the Western lifestyle and eventually infertility.
Probiotics can prevent a number of complications of pregnancy that otherwise lead to miscarriage and infertility. In fact, according to a few proponents, probiotic therapy should be specifically implemented in women who lack appropriate access to health care and proper nutrition. 
Probiotics can help fight Obesity
In addition to their direct effects on reproductive potential, the live, healthy bacteria can help combat obesity. What is the relation of obesity to infertility? Just like low body weight compromises your ability to get pregnant, a high body mass index also has a negative impact on fertility. 
If being obese is contributing to your infertility, probiotics may enable you to conceive by helping you lose some extra pounds.
Probiotics can fix Bacterial Vaginosis (BV) and prevent reproductive complications
Recurrent bacterial vaginosis (a vaginal infection where the vagina becomes host to harmful bugs) can wreak havoc on the child-bearing potential of a woman.  Studies reveal that probiotics whether taken via mouth or applied topically into the vagina, replace the unhealthy vaginal microbiota of BV. This, in turn, helps cure the infection and ensuing infertility. The low pH and production of antimicrobial substances also account for the protective effects of lactobacilli against BV and subsequent infertility. 
Probiotics can also influence Assisted Reproductive Technology
Gynecologic experts have also documented the most cutting-edge use of probiotics for infertility. It appears that during the embryo-transfer phase of assisted reproduction, colonizing the tip of the transfer tube with certain Lactobacillus strains may promote attachment of the embryo to a woman’s uterus and subsequently boost the odds of getting pregnant. 
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