Effect of vaginal microbiota dysbiosis on live birth outcomes in patients with cervical incompetence

doi:10.3969/j.issn.1674-8115.2026.09.008

Abstract

Abstract:

Objective ·To investigate the impact of vaginal microbiota dysbiosis on pregnancy outcomes in patients with cervical incompetence using stabilized inverse probability of treatment weighting (sIPTW) and Logistic regression. Methods ·A retrospective analysis was conducted on the clinical data of 756 patients with cervical incompetence who visited the Department of Obstetrics and Gynecology, The Second Affiliated Hospital of Soochow University, between January 2013 and December 2023. Based on the results of vaginal secretion culture in the second trimester, the patients were divided into a microbiota dysbiosis group (pathogenic bacteria were detected and lactobacilli were absent or significantly reduced) and a normal microbiota group (lactobacilli were the dominant bacteria and no pathogenic bacteria were detected). The sIPTW method was employed to balance variables such as parity, gravidity, number of late miscarriages, and cervical length. The differences in pregnancy outcomes between the vaginal microbiota dysbiosis group and the normal microbiota group before and after sIPTW were compared, including the full-term delivery rate, live birth rate, miscarriage rate, preterm birth rate, neonatal birth weight, and gestational age at delivery. Univariate conditional Logistic regression analysis was conducted to investigate the influencing factors of live birth outcomes. Results ·A total of 756 patients with cervical insufficiency were included, including 216 cases in the microbiota dysbiosis group and 540 cases in the normal microbiota group. Prior to sIPTW, the vaginal microbiota dysbiosis group and the normal microbiota group exhibited significant differences in body mass index (BMI), cervical length, cervical internal os dilation, and whether cervical cerclage was performed (P<0.05). After sIPTW, no statistically significant differences were observed in clinical data between the two groups. Before and after sIPTW, the full-term delivery rate and live birth rate in the vaginal microbiota dysbiosis group were significantly lower than those in the normal microbiota group. The miscarriage rate and preterm birth rate were significantly higher in the microbiota dysbiosis group, while neonatal birth weight and gestational age at delivery were significantly lower (all P<0.05). Univariate conditional Logistic regression analysis showed that cervical cerclage (OR=1.090, P<0.010), abnormal physical examination (OR=0.888, P<0.001), vaginal microbiota dysbiosis (OR=0.932, P=0.003), and no history of late miscarriage (OR=0.827, P=0.008) were major factors influencing live birth outcomes. Conclusion ·Vaginal microbiota dysbiosis significantly reduces the live birth rate and full-term delivery rate in patients with cervical incompetence, and increases the risk of miscarriage and premature birth.

Key words: vaginal microbiota dysbiosis, inverse probability weighting, cervical incompetence, live birth

CLC Number:

R713.4

Li Xue, Zhou Ling, Li Ji, Liu Juanjuan, Zhang Hong. Effect of vaginal microbiota dysbiosis on live birth outcomes in patients with cervical incompetence[J]. Journal of Shanghai Jiao Tong University (Medical Science), 2026,(9): 1233-1241.

Figures/Tables 5

TrendMD

References 26

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Characteristic	Before sIPTW				After sIPTW
Characteristic	Normal group (n=540)	Vaginal dysbiosis group (n=216)	P value	SMD	Normal group (n=544.07)	Vaginal dysbiosis group (n=216.69)	P value	SMD
Age/n(%)			0.110	0.145			0.767	0.030
≤35 years	477 (88.3)	200 (92.6)			487.7 (89.6)	192.2 (88.7)
>35 years	63 (11.7)	16 (7.4)			56.4 (10.4)	24.5 (11.3)
BMI/(kg·m^-2)	22.41 (20.82, 24.41)	21.91 (20.44, 23.94)	0.011	0.198	22.21 (20.69, 24.30)	22.22 (20.69, 24.61)	0.763	0.063
Gravidity/n(%)			0.836	0.049			0.797	0.059
1	24 (4.4)	8 (3.7)			22.5 (4.1)	6.7 (3.1)
2	230 (42.6)	96 (44.4)			235.8 (43.3)	96.6 (44.6)
≥3	286 (53.0)	112 (51.9)			285.8 (52.5)	113.5 (52.4)
Parity/n(%)			0.235	0.110			0.769	0.028
0	483 (89.4)	200 (92.6)			491.2 (90.3)	197.4 (91.1)
≥1	57 (10.6)	16 (7.4)			52.9 (9.7)	19.3 (8.9)
Prior history of cerclage/n(%)			0.772	0.036			0.355	0.101
No	500 (92.6)	202 (93.5)			504.6 (92.7)	194.8 (89.9)
Yes	40 (7.4)	14 (6.5)			39.5 (7.3)	21.9 (10.1)
Number of late miscarriage/n(%)			0.864	0.043			0.915	0.036
0	49 (9.1)	22 (10.2)			50.7 (9.3)	18.0 (8.3)
1	309 (57.2)	120 (55.6)			310.5 (57.1)	125.8 (58.1)
≥2	182 (33.7)	74 (34.3)			182.8 (33.6)	72.8 (33.6)
Cervical examination/n(%)			0.131	0.128			0.975	0.003
Normal	363 (67.2)	132 (61.1)			351.1 (64.5)	140.1 (64.7)
Abnormal	177 (32.8)	84 (38.9)			193.0 (35.5)	76.6 (35.3)
Methods of pregnancy/n(%)			0.164	0.128			0.589	0.061
Natural pregnancy	483 (89.4)	201 (93.1)			492.9 (90.6)	192.3 (88.7)
IVF	57 (10.6)	15 (6.9)			51.2 (9.4)	24.4 (11.3)
History of LEEP/n(%)			0.180	0.131			0.717	0.040
No	511 (94.6)	210 (97.2)			518.8 (95.4)	204.7 (94.5)
Yes	29 (5.4)	6 (2.8)			25.3 (4.6)	12.0 (5.5)
History of PCOS/n(%)			0.490	0.077			0.649	0.044
No	533 (98.7)	211 (97.7)			530.9 (97.6)	212.8 (98.2)
Yes	7 (1.3)	5 (2.3)			13.2 (2.4)	3.9 (1.8)
Cervical length/n(%)			0.007	0.249			0.822	0.055
<25 mm	73 (13.5)	48 (22.2)			91.4 (16.8)	35.6 (16.4)
25‒30 mm	173 (32.0)	71 (32.9)			175.9 (32.3)	75.6 (34.9)
>30 mm	294 (54.4)	97 (44.9)			276.8 (50.9)	105.5 (48.7)
Dilation of cervical os/n(%)			0.009	0.214			0.754	0.027
No	423 (78.3)	149 (69.0)			405.1 (74.4)	163.8 (75.6)
Yes	117 (21.7)	67 (31.0)			139.0 (25.6)	52.9 (24.4)
Cervical cerclage/n(%)			<0.001	0.379			0.672	0.036
No	146 (27.0)	97 (44.9)			178.2 (32.8)	67.4 (31.1)
Yes	394 (73.0)	119 (55.1)			365.9 (67.2)	149.3 (68.9)

Characteristic	Before sIPTW				After sIPTW
Characteristic	Normal group (n=540)	Vaginal dysbiosis group (n=216)	P value	SMD	Normal group (n=544.07)	Vaginal dysbiosis group (n=216.69)	P value	SMD
Age/n(%)			0.110	0.145			0.767	0.030
≤35 years	477 (88.3)	200 (92.6)			487.7 (89.6)	192.2 (88.7)
>35 years	63 (11.7)	16 (7.4)			56.4 (10.4)	24.5 (11.3)
BMI/(kg·m^-2)	22.41 (20.82, 24.41)	21.91 (20.44, 23.94)	0.011	0.198	22.21 (20.69, 24.30)	22.22 (20.69, 24.61)	0.763	0.063
Gravidity/n(%)			0.836	0.049			0.797	0.059
1	24 (4.4)	8 (3.7)			22.5 (4.1)	6.7 (3.1)
2	230 (42.6)	96 (44.4)			235.8 (43.3)	96.6 (44.6)
≥3	286 (53.0)	112 (51.9)			285.8 (52.5)	113.5 (52.4)
Parity/n(%)			0.235	0.110			0.769	0.028
0	483 (89.4)	200 (92.6)			491.2 (90.3)	197.4 (91.1)
≥1	57 (10.6)	16 (7.4)			52.9 (9.7)	19.3 (8.9)
Prior history of cerclage/n(%)			0.772	0.036			0.355	0.101
No	500 (92.6)	202 (93.5)			504.6 (92.7)	194.8 (89.9)
Yes	40 (7.4)	14 (6.5)			39.5 (7.3)	21.9 (10.1)
Number of late miscarriage/n(%)			0.864	0.043			0.915	0.036
0	49 (9.1)	22 (10.2)			50.7 (9.3)	18.0 (8.3)
1	309 (57.2)	120 (55.6)			310.5 (57.1)	125.8 (58.1)
≥2	182 (33.7)	74 (34.3)			182.8 (33.6)	72.8 (33.6)
Cervical examination/n(%)			0.131	0.128			0.975	0.003
Normal	363 (67.2)	132 (61.1)			351.1 (64.5)	140.1 (64.7)
Abnormal	177 (32.8)	84 (38.9)			193.0 (35.5)	76.6 (35.3)
Methods of pregnancy/n(%)			0.164	0.128			0.589	0.061
Natural pregnancy	483 (89.4)	201 (93.1)			492.9 (90.6)	192.3 (88.7)
IVF	57 (10.6)	15 (6.9)			51.2 (9.4)	24.4 (11.3)
History of LEEP/n(%)			0.180	0.131			0.717	0.040
No	511 (94.6)	210 (97.2)			518.8 (95.4)	204.7 (94.5)
Yes	29 (5.4)	6 (2.8)			25.3 (4.6)	12.0 (5.5)
History of PCOS/n(%)			0.490	0.077			0.649	0.044
No	533 (98.7)	211 (97.7)			530.9 (97.6)	212.8 (98.2)
Yes	7 (1.3)	5 (2.3)			13.2 (2.4)	3.9 (1.8)
Cervical length/n(%)			0.007	0.249			0.822	0.055
<25 mm	73 (13.5)	48 (22.2)			91.4 (16.8)	35.6 (16.4)
25‒30 mm	173 (32.0)	71 (32.9)			175.9 (32.3)	75.6 (34.9)
>30 mm	294 (54.4)	97 (44.9)			276.8 (50.9)	105.5 (48.7)
Dilation of cervical os/n(%)			0.009	0.214			0.754	0.027
No	423 (78.3)	149 (69.0)			405.1 (74.4)	163.8 (75.6)
Yes	117 (21.7)	67 (31.0)			139.0 (25.6)	52.9 (24.4)
Cervical cerclage/n(%)			<0.001	0.379			0.672	0.036
No	146 (27.0)	97 (44.9)			178.2 (32.8)	67.4 (31.1)
Yes	394 (73.0)	119 (55.1)			365.9 (67.2)	149.3 (68.9)

Vaginal microbiota	Total (n=756)
Enterococcus faecalis/n(%)	10 (1.32)
Candida albicans/n(%)	48 (6.35)
Candida tropicalis/n(%)	4 (0.53)
Candida glabrata/n(%)	23 (3.04)
Escherichia coli/n(%)	30 (3.97)
Streptococcus agalactiae/n(%)	14 (1.85)
Gardnerella vaginalis/n(%)	54 (7.14)
Klebsiella pneumoniae/n(%)	4 (0.53)
Staphylococcus aureus/n(%)	9 (1.12)
Proteus mirabilis/n(%)	8 (1.06)
Haemophilus parainfluenzae/n(%)	3 (0.40)
Enterobacter aerogenes/n(%)	1 (0.13)
Hemophilus ducreyi/n(%)	1 (0.13)
Streptococcus milleri/n(%)	1 (0.13)
Staphylococcus haemolyticus/n(%)	1 (0.13)
Morganella morganii/n(%)	1 (0.13)
Burkholderia cepacia/n(%)	1 (0.13)
Enterobacter cloacae/n(%)	3 (0.40)

Vaginal microbiota	Total (n=756)
Enterococcus faecalis/n(%)	10 (1.32)
Candida albicans/n(%)	48 (6.35)
Candida tropicalis/n(%)	4 (0.53)
Candida glabrata/n(%)	23 (3.04)
Escherichia coli/n(%)	30 (3.97)
Streptococcus agalactiae/n(%)	14 (1.85)
Gardnerella vaginalis/n(%)	54 (7.14)
Klebsiella pneumoniae/n(%)	4 (0.53)
Staphylococcus aureus/n(%)	9 (1.12)
Proteus mirabilis/n(%)	8 (1.06)
Haemophilus parainfluenzae/n(%)	3 (0.40)
Enterobacter aerogenes/n(%)	1 (0.13)
Hemophilus ducreyi/n(%)	1 (0.13)
Streptococcus milleri/n(%)	1 (0.13)
Staphylococcus haemolyticus/n(%)	1 (0.13)
Morganella morganii/n(%)	1 (0.13)
Burkholderia cepacia/n(%)	1 (0.13)
Enterobacter cloacae/n(%)	3 (0.40)

Pregnancy outcome	Before sIPTW			After sIPTW
Pregnancy outcome	Normal group (n=540)	Vaginal dysbiosis group (n=216)	P value	Normal group (n=544.1)	Vaginal dysbiosis group (n=216.7)	P value
Term birth/n(%)	433 (80.2)	105 (48.6)	<0.001	422.6 (77.7)	111.4 (51.4)	<0.001
Miscarriage/n(%)	43 (8.0)	41 (19.0)	<0.001	46.4 (8.5)	32.1 (14.8)	<0.001
Preterm birth/n(%)	64 (11.9)	70 (32.4)	<0.001	75.1 (13.8)	73.2 (33.8)	<0.001
Live birth/n(%)	503 (93.1)	177 (81.9)	<0.001	503.1 (92.5)	186.0 (85.8)	0.006
Pregnancy complication/n(%)	49 (9.1)	28 (13.0)	0.143	50.7 (9.3)	38.7 (17.9)	0.013
Birth weight/g	3 154.44±532.49	2 841.44±690.62	<0.001	3 141.26±544.59	2 887.90±695.62	<0.001
Gestational age at delivery/week	37.66±2.22	36.48±2.82	<0.001	37.59±2.27	36.59±2.81	<0.001
Vaginal delivery/n(%)	428 (85.1)	156 (88.1)	0.381	428.1 (85.1)	161.1 (86.6)	0.678
Cesarean section/n(%)	75 (14.9)	21 (11.9)	0.317	75.0 (14.9)	24.9 (13.4)	0.398