Evidence Based This post has 26 references

Can Probiotics Help Fertility, Pregnancy & Infant Growth?

Written by Biljana Novkovic, PhD | Last updated:
Jonathan Ritter
Puya Yazdi
Medically reviewed by
Jonathan Ritter, PharmD, PhD (Pharmacology), Puya Yazdi, MD | Written by Biljana Novkovic, PhD | Last updated:

Probiotics have been linked with improved outcomes in endometriosis, pregnancy, and health outcomes for mother and child before and after birth. Which strains are best? Read on to learn more.

Probiotics & Reproductive Health

Pregnancy and birth are among the most vulnerable processes in the life of both mother and child, and probiotics supplements may support immune function and prevent reproductive dysfunction during this time.

However, probiotic supplements may not be for everyone. It’s important to talk to your doctor about any health strategies you want to employ during pregnancy, including probiotics.

Possibly Effective For

1) Pregnancy

The use of a specific set of probiotics during the first 1,500 days of life may lower the risk of infections and inflammatory events in infants [1].

L. rhamnosus affected the immune regulation and immune responses favorably in mothers and offspring. In addition, some of the beneficial effects of prenatal L. rhamnosus supplementation extended into postnatal life of the offspring, suggesting a possible immune programming effect of L. rhamnosus [2].

Prenatal supplementation with L. rhamnosus has been reported to change the composition of the newborn microbiota, promoting a beneficial profile dominated by Bifidobacteria [3].

The intake of milk fermented with L. casei during the lactation period modestly contributed to the modulation of the mother’s immunological response after delivery and decreased the incidence of gastrointestinal episodes in the breastfed child [4].

B. animalis spp. lactis supplementation in pregnancy has the potential to influence fetal immune parameters as well as immunomodulatory factors in breast milk [5].

B. animalis ssp. lactis mitigated the negative immune-related effects of not breastfeeding and cesarean delivery by augmenting the immune response, evidenced by increased anti-rotavirus- and anti-poliovirus-specific IgA [6].

Oral administration of L. salivarius during late pregnancy appeared to prevent breast infection in pregnant women [7].

L. acidophilus, L. casei and B. bifidum significantly decreased fasting plasma glucose, insulin levels, and insulin resistance and increased insulin sensitivity in pregnant women with gestational diabetes mellitus. In addition, significant decreases in serum triglycerides and VLDL cholesterol concentrations were recorded [8].

B. coagulans containing symbiotic decreased blood insulin levels, HOMA-IR, and HOMA-B in pregnant women [9].

Preeclampsia is associated with an impaired antioxidant defense that results in maternofetal complications. S. cerevisiae scavenged nitric oxide radicals and decreased oxidative stress in red blood cells and alleviated stress status in the preeclamptic fetus [10].

Continuous consumption of fermented milk containing L. casei alleviated constipation-related symptoms, provided satisfactory bowel habit, and resulted in earlier recovery from hemorrhoids in women after childbirth [11].

L. fermentum alleviated pain and reduced the load of Staphylococcus in the breastmilk of women suffering from painful breastfeeding [12].

During pregnancy and immediately after birth, probiotics improved the health and microbiota composition of both the mother and infant.

Insufficient Evidence For

The following purported benefits are only supported by limited, low-quality clinical studies. There is insufficient evidence to support the use of probiotics for any of the below-listed uses. Remember to speak with a doctor before taking probiotic supplements, and never use it in place of something your doctor recommends or prescribes.

2) Endometriosis

L. gasseri improved menstrual pain and dysmenorrhea in patients with endometriosis [13].

L. gasseri also inhibited the growth of endometrial tissue in the abdominal cavity in mice and rats [14].

3) Infant Growth

B. animalis spp. lactis supplementation had a positive effect on growth in vulnerable infants, such as infants born to mothers with HIV [15], and preterm infants [16].

B. breve significantly decreased aspirated air volume and improved weight gain in very low birth weight infants [17].

L. plantarum strain maintained the growth of infant mice during chronic undernutrition [18].

4) Feeding Tolerance in Infants

Preterm infants supplemented with B. coagulans had improved feeding tolerance [19].

Prophylactic supplementation of S. boulardii improved weight gain and feeding tolerance and had no adverse effects in preterm infants >30 weeks old [20].

Orally administered S. boulardii improved feeding tolerance and clinical sepsis in very-low-birth-weight (VLBW) infants [21].

Animal Research (Lacking Evidence)

No clinical evidence supports the use of probiotics for any of the conditions listed in this section. Below is a summary of the existing animal and cell-based research, which should guide further investigational efforts. However, the studies listed below should not be interpreted as supportive of any health benefit.

5) Testosterone

L. reuteri sustained youthful serum testosterone levels and testicular size in aging mice [22, 23].

A probiotic containing L. acidophilus, B. bifidum, and L. helveticus elevated testosterone levels in rabbits [24].

6) Female Fertility

L. plantarum ameliorated inflammation-induced infertility in mice [25].

L. plantarum reinforced natural microflora and lead to a resurge of fertility in mice infected with E. coli [26].

7) Oxytocin

L. reuteri increased the levels of the “feel-good” hormone oxytocin in mice [23].


Probiotics have produced promising results in a number of clinical trials on pregnancy, birth, and fertility outcomes. When pregnant women took probiotic supplements, both their and their newborn’s health improved before and after parturition: both mother and infant had improved immunity, and newborns had improved microbiota composition.

Animal research suggests that probiotics may also benefit male fertility (by maintaining testosterone production), odds of conception, and oxytocin release (linked with social bonding).

Further Reading

We’ve compiled deep dives into each potential benefit of probiotics. Check them out here:

About the Author

Biljana Novkovic

Biljana Novkovic

Biljana received her PhD from Hokkaido University.
Before joining SelfHacked, she was a research scientist with extensive field and laboratory experience. She spent 4 years reviewing the scientific literature on supplements, lab tests and other areas of health sciences. She is passionate about releasing the most accurate science and health information available on topics, and she's meticulous when writing and reviewing articles to make sure the science is sound. She believes that SelfHacked has the best science that is also layperson-friendly on the web.


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