Table 3.
Endometrial microbiota characteristics by birth outcome.
| LB (n = 38) | NLBa (n = 54) | p LB vs. all NLBb | p NP vs. PLb | |||
|---|---|---|---|---|---|---|
| All NLB (n = 54) | NP (n = 46) | PL (n = 8) | ||||
| Alpha diversity | ||||||
| Mean inverse Simpson diversity (SD) | 2.7 (± 1.6) | 2.8 (± 2.4) | 2.6 (± 2.0) | 4.1 (± 3.9) | 0.654 | 0.154 |
| Mean Chao1 diversity (SD) | 15.9 (± 26.7) | 13.5 (± 15.9) | 12.7 (± 16.2) | 18.0 (± 14.0) | 0.769 | 0.073 |
| Untargeted ANCOM-BC resultsb,c | ||||||
| Mean RA Aerococcus genus (SD) | 0.2 (± 1.2) | 0.1 (± 0.5) | 0.2 (± 0.5) | 0 | NS | < 0.001 |
| Mean RA Corynebacterium genus (SD) | 3.3 (± 11.5) | 1.9 (± 6.0) | 2.0 (± 6.5) | 1.0 (± 1.7) | NS | < 0.001 |
| Targeted bacterial groups (specified a priori)b,c | ||||||
| Lactobacillus genus | 0.893 | 0.450 | ||||
| Median RA (IQR) | 94.2 (39.1–99.2) | 94.5 (18.9–99.6) | 95.8 (32.5–99.7) | 48.1 (7.6–98.4) | ||
| 95% CI | 80.1–97.7 | 69.9–98.8 | 69.9–99.3 | 1.5–100.0 | ||
| Mean RA (SD) | 73.5 (± 35.2) | 66.4 (± 41.5) | 69.0 (± 40.6) | 51.0 (± 46.5) | ||
| 95% CI | 61.2–77.4 | 55.0–77.7 | 57.0–81.1 | 12.2–89.9 | ||
| L. crispatus | 0.029 | 0.510 | ||||
| Median RA (IQR) | 37.4 (0–94.4) | 0 (0–55.7) | 0 (0–55.7) | 4.2 (0–37.8) | ||
| 95% CI | 0–91.5 | 0–0 | 0–0 | 0–99.5 | ||
| Mean RA (SD) | 45.8 (± 44.3) | 25.4 (± 41.4) | 25.0 (± 41.4) | 27.9 (± 44.1) | ||
| 95% CI | 31.2–60.4 | 14.1–36.7 | 12.7–37.3 | 0–64.8 | ||
| L. iners | 0.141 | 0.971 | ||||
| Median RA (IQR) | 0 (0–15.9) | 0.3 (0–71.7) | 0.2 (0–71.7) | 0.3 (0–22.3) | ||
| 95% CI | 0–5.5 | 0–21.5 | 0–63.1 | 0–92.8 | ||
| Mean RA (SD) | 16.5 (± 30.6) | 30.2 (± 40.5) | 31.6 (± 41.0) | 21.7 (± 39.0) | ||
| 95% CI | 6.4–26.5 | 19.1–41.2 | 19.5–43.8 | 0–54.3 | ||
| Other lactobacilli | 0.203 | 0.495 | ||||
| Median RA (IQR) | 0.7 (0–5.0) | 0 (0–4.4) | 0 (0–6.8) | 0.5 (0.2–1.4) | ||
| 95% CI | 0–2.6 | 0–0.6 | 0–0.6 | 0–6.6 | ||
| Mean RA (SD) | 11.2 (± 24.5) | 10.8 (± 27.1) | 12.4 (± 29.0) | 1.3 (± 2.2) | ||
| 95% CI | 3.1–19.3 | 3.4–18.1 | 3.8–21.0 | 0–3.2 | ||
| Gardnerella genus | 0.541 | 1.000 | ||||
| Median RA (IQR) | 0 (0–0) | 0 (0–1.6) | 0 (0–1.6) | 0 (0–9.3) | ||
| 95% CI | 0–0 | 0–0 | 0–0 | 0–98.3 | ||
| Mean RA (SD) | 8.6 (± 20.3) | 14.0 (± 28.7) | 13.4 (± 27.8) | 16.9 (± 35.4) | ||
| 95% CI | 2.0–15.3 | 6.1–21.8 | 5.2–21.7 | 0–46.5 | ||
| Other BV-anaerobes | 0.558 | 0.802 | ||||
| Median RA (IQR) | 0 (0–1.5) | 0 (0–2.6) | 0 (0–4.5) | 0.1 (0–0.6) | ||
| 95% CI | 0–2.4 | 0–1.4 | 0–0.6 | 0–58.6 | ||
| Mean RA (SD) | 4.4 (± 10.8) | 8.3 (± 18.8) | 8.4 (± 18.7) | 7.6 (± 20.6) | ||
| 95% CI | 0.9–8.0 | 3.2–13.4 | 2.9–14.0 | 0–24.8 | ||
| Other bacteriad | 0.045 | 0.233 | ||||
| Median RA (IQR) | 4.7 (0.3–13.2) | 0.5 (0–8.9) | 0.4 (0–5.9) | 1.2 (0.1–36.8) | ||
| 95% CI | 0.8–6.9 | 0.1–1.4 | 0–1.4 | 0–91.4 | ||
| Mean RA (SD) | 13.5 (± 23.7) | 11.4 (± 22.8) | 9.1 (± 18.6) | 24.5 (± 38.5) | ||
| 95% CI | 5.7–21.2 | 5.2–17.6 | 3.6–14.6 | 0–56.6 | ||
| L. crispatus RA subgroups, n (%) | 0.015 | 0.679 | ||||
| ≤ 10 | 16 (42.1) | 38 (70.4) | 33 (71.7) | 5 (62.5) | ||
| 11–89 | 9 (23.7) | 4 (7.4) | 3 (6.5) | 1 (12.5) | ||
| ≥ 90 | 13 (34.2) | 12 (22.2) | 10 (21.7) | 2 (25.0) | ||
Significant values are in [bold].
BV bacterial vaginosis, CI confidence interval, IQR interquartile range, LB live birth, mo months, NLB no live birth, NP no pregnancy, NS not significant, PL pregnancy loss, RA relative abundance, SD standard deviation.
Only samples with ≥ 100 16S rRNA sequencing reads (V1–V2 region) were included.
aThe NLB participants included participants with a pregnancy loss (PL) as well as participants who did not get pregnant at all (NP).
bANCOM-BC analyses were corrected for multiple testing and were used to identify individual taxa with significantly different RAs in comparison groups in an untargeted manner. In the targeted analyses (using prespecified bacterial groups and subgroups), we assumed that the data were not normally distributed. All p-values were calculated by Wilcoxon rank sum tests only, but we are showing both median and mean RAs for illustrative purposes.
cRelative abundances are presented as percentages of the number of reads of the taxon out of the total number of bacterial reads.
dThe group of “other bacteria” contains skin bacteria, unresolved bacteria and minority taxa that could not be assigned to any of the other categories.