| Table 4. Articles on vaginal and endometrial microbiomes and ART outcomes (without repeated implantation failure). | ||||||
| Author | Sample (n) | Average age (y) |
Analysis | Design | Relationship between microbiome and ART outcomes | ART outcomes (Pregnant, bioprofile) |
|---|---|---|---|---|---|---|
| VAGINA | ||||||
| Hyman et al., 2012 | 30 | 38.5 | BigDye Terminator, ABI 3730 | Microbiome occupancy was assessed in patients who underwent IVF-ET. | not related | Lactobacillus is favorable but not sufficient for successful ET. |
| Moreno et al., 2016 | 13 | 39.5 | 454 pyrosequencing V3-V5 | Pregnancy outcomes were compared in women who underwent IVF. | Related | NLDM (<90%) was associated with significant decreases in pregnancy (70.6% vs. 33.3%; p=.03) and live birth (58.8% vs. 6.7%; p=.002) rates. |
| Koedooder et al., 2019 | 192 | 31.5 | Interspace profiling (IS-pro) molecular technique | Pregnancy outcomes were compared in 192 women who underwent IVF via fresh ET. | Related | High Lactobacillus abundance seemed to be related to IVF and ICSI. Women who had <60% L. crispatus had a high chance of pregnancy. |
| Bernabeu et al., 2019 | 31 | 40 | V3-V4 Illumina MiSeq | Pregnancy outcomes were compared between 17 pregnant women and 14 nonpregnant women after undergoing ICSI-ET | tend to be related | α-diversity was found in nonpregnant patients compared with that in pregnant patients, although this difference was not significant (p=0.088). |
| Present study | 35 | 36 | Illumina MiSeq V1, V2 | The vaginal microbiome profiles of 34 women who underwent good ET with IVF were compared (21 pregnant cases vs. 13 nonpregnant cases). | Related | The vaginal microbiomes of pregnant cases demonstrated significantly more cases of high abundance of Lactobacillus and low abundance of pathogenic bacteria. The balance of bacterial flora was important for pregnancy. |
| ENDOMETRIUM | ||||||
| Franasiak et al., 2016 | 33 | 35.9 | Ion16S metagenomics V2-4-8, V3-6, V7-9 | Pregnancy outcomes of women who underwent single ET of an euploid blastocyst were examined; 18 women were pregnant and 15 were not. | not related | Lactobacillus was the top species call for both outcomes. No differences were found between pregnant and nonpregnant women. |
| Moreno et al., 2016 | 13 | 39.5 | 454 pyrosequencing V3-5 | Pregnancy outcomes of women who underwent IVF were compared. | Related | NLDM (<90%) was associated with significant decreases in pregnancy (70.6% vs. 33.3%; p=.03) and live birth (58.8% vs. 6.7%; p=.002) rates. |
| Kyono et al., 2019 | 92 | 37 | Illumina MiSeq V4 | Pregnancy outcomes of 92 IVF cases (47 LDM cases and 45 NLDM cases) and 9 NLDM cases receiving antibiotics and prebiotics were compared. | Tend to be related | After intervention, 9 NLDM cases became LDM (46 LDM cases vs. 36 NLDM cases). Pregnancy rates were higher in the LDM group (58.9%) than in the NLDM group (47.2%), but no significant difference was found. |
| Hashimoto & Kyono, 2019 | 99 | 33.5 | Illumina MiSeq V4 | Pregnancy outcomes of 99 IVF cases were compared between dysbiotic endometrium (n=31) and eubiotic endometrium (n=68). | not related | Pregnancy rates were comparable between eubiotic and dysbiotic microbiome endometria. |
| Present study | 35 | 36 | Illumina MiSeq V1, V2 | The endometrial microbiome profiles of 34 women who underwent good ET with IVF were compared (21 pregnant cases vs. 13 nonpregnant cases). | Related | The endometrial microbiomes of pregnant cases demonstrated significantly more cases of high occupancy of Lactobacillus and low occupancy of pathogenic bacteria. The balance of bacterial flora was important for pregnancy. |
ART, Assisted reproductive technology; ET, embryo transfer; ICSI, intracytoplasmic sperm injection; IVF, in vitro fertilization; LDM, Lactobacillus-dominant microbiota; NLDM, non-Lactobacillus-dominant microbiota.