First-trimester vaginal microbiome diversity: A potential indicator of preterm delivery risk

Background: We investigated the composition and dynamic changes of vaginal microbiota (VM) in pregnant women who underwent in vitro fertilization (IVF), as well as VM in relation to preterm birth. Methods: Sixteen women who conceived after IVF and 6 women who conceived naturally were recruited to the study. Vaginal samples from all participants were collected in the first, second, and third trimesters of pregnancy (T1, T2 and T3, respectively). The V3–V4 region of 16S rRNA was sequenced to assess the VM. Results: In all participants, the alpha-diversity indices Chao1 and observed species of VM were significantly higher in T1 compared to T2 and T3. Non-metric multi-dimensional scaling (NMDS) analysis of beta-diversity revealed the VM structure during T1 was significantly different between IVF and control groups, but then gradually converged during T3. A greater abundance of potential pathogenic bacteria and lower abundance of commensal bacteria was observed in the IVF group compared to control group during T1. Moreover, a higher abundance of Lactobacillus_iners, Escherichia_coli and Alloscardovia_omnicolens was found in preterm birth women who underwent IVF. Conclusions: The VM diversity decreased with increasing gestation in women who underwent IVF and in healthy controls. IVF-induced dysbiosis of the VM occurs mainly during T1 of gestation and may be related to preterm birth.

BackgroundThis study was undertaken to characterize the vaginal microbiota throughout normal human pregnancy using sequence-based techniques. We compared the vaginal microbial composition of non-pregnant patients with a group of pregnant women who delivered at term.ResultsA retrospective case–control longitudinal study was designed and included non-pregnant women (n = 32) and pregnant women who delivered at term (38 to 42 weeks) without complications (n = 22). Serial samples of vaginal fluid were collected from both non-pregnant and pregnant patients. A 16S rRNA gene sequence-based survey was conducted using pyrosequencing to characterize the structure and stability of the vaginal microbiota. Linear mixed effects models and generalized estimating equations were used to identify the phylotypes whose relative abundance was different between the two study groups. The vaginal microbiota of normal pregnant women was different from that of non-pregnant women (higher abundance of Lactobacillus vaginalis, L. crispatus, L. gasseri and L. jensenii and lower abundance of 22 other phylotypes in pregnant women). Bacterial community state type (CST) IV-B or CST IV-A characterized by high relative abundance of species of genus Atopobium as well as the presence of Prevotella, Sneathia, Gardnerella, Ruminococcaceae, Parvimonas, Mobiluncus and other taxa previously shown to be associated with bacterial vaginosis were less frequent in normal pregnancy. The stability of the vaginal microbiota of pregnant women was higher than that of non-pregnant women; however, during normal pregnancy, bacterial communities shift almost exclusively from one CST dominated by Lactobacillus spp. to another CST dominated by Lactobacillus spp.ConclusionWe report the first longitudinal study of the vaginal microbiota in normal pregnancy. Differences in the composition and stability of the microbial community between pregnant and non-pregnant women were observed. Lactobacillus spp. were the predominant members of the microbial community in normal pregnancy. These results can serve as the basis to study the relationship between the vaginal microbiome and adverse pregnancy outcomes.

Introduction: Preterm birth is the leading cause of perinatal mortality worldwide, with prevalence rates showing little reduction. Although mortality rates have decreased, morbidity rates remain concerningly high. In recent years, there has been a surge in studies examining the etiology, risk factors, and management of preterm birth. The use of vaginal probiotics in pregnant women at risk of preterm birth has garnered attention as a potential approach for improving perinatal outcomes and modulating the vaginal microbiota. However, the efficacy of this intervention remains unclear. Therefore, this study explored the impact of vaginal probiotics on perinatal outcomes and vaginal microbiota composition in pregnant women at risk of preterm birth. Materials and Methods: This was a randomized, prospective, longitudinal, double-blind, placebo-controlled, multicentric trial conducted across seven maternities in Spain from October 2017 to August 2022 in pregnant women at risk of preterm birth. Participants were randomly assigned to receive vaginal probiotics containing four lactobacilli strains or a placebo. The primary outcome was to explore a potential correlation between probiotic use among pregnant women at risk of preterm birth and the actual rate of preterm birth before 37 gestational weeks. Secondary outcomes included an evaluation of preterm birth rates, neonatal morbidity, the vaginal microbiota, and changes in the vaginal microbiota after receiving probiotics. Other secondary outcomes were identifying vaginal microbiota patterns associated with preterm birth and exploring potential therapeutic mechanisms involving probiotics. Trial registration: Clinicaltrials.gov, identifier: NCT03689166. Results: A total of 200 participants were included. Of those, birth data were obtained for 181 women. Demographics were similar between both groups. An analysis of perinatal outcomes found no significant differences in preterm birth rates, prematurity rates, gestational weeks at delivery, neonatal complications, time to birth, or latency time to delivery. Microbiota analysis showed no significant differences in vaginal microbiota changes between groups. No serious or unexpected adverse reactions were reported. Conclusions: There were no statistically significant differences for spontaneous preterm birth between pregnant women receiving probiotics and pregnant women receiving the placebo.

BackgroundThe vaginal microbiota (VMB) are the set of microorganisms residing in the human vagina. During pregnancy, their composition is Lactobacillus-dominant in most Caucasian women. Previous studies suggest that the VMB of women with African ancestry is more likely to be non-Lactobacillus dominant (dysbiotic) compared to other populations, and possibly relate to the high incidence of pregnancy complications, such as preterm birth. This work reviewed the literature on VMB composition in pregnant women from sub-Saharan Africa.MethodsA search was conducted in PubMed and Embase databases following PRISMA guidelines. Observational and intervention studies analysing VMB communities from sub-Saharan African pregnant women using molecular techniques were included.ResultsTen studies performed in seven sub-Saharan African countries were identified. They independently showed that Lactobacillus-dominant VMB (particularly L. iners or L. crispatus) or VMB containing Lactobacilli are the most prevalent, followed by a more diverse anaerobe-dominant VMB, in the studied populations. The majority of pregnant women with a sexually-transmitted infection had a Lactobacillus-dominant VMB, but with a significantly higher presence of anaerobic species.ConclusionIn agreement with studies performed in other populations, Lactobacillus species are the most prevalent VMB species during pregnancy in sub-Saharan African women. The frequency of diverse anaerobe-dominant VMB is high in these populations. In Africa, studies on VMB in pregnancy are scant, heterogeneous in methodology, and knowledge remains limited. More insights on VMB composition and their possible sequalae among these populations is needed.

BackgroundPregnant women living with HIV infection (PWLWH) have elevated rates of preterm birth (PTB) in which HIV and cART are implicated. PWLWH also have a high prevalence of adverse vaginal microbiota, which associate with genital tract inflammation. The mechanism underlying PTB in PWLWH is unknown. We present the first data in PWLWH on genital-tract matrix-metalloproteinase-9(MMP-9), an important collagenase implicated in labour onset, and tissue inhibitor of metalloproteinases-1(TIMP-1) and explore correlations with local inflammation and vaginal bacteria.Material and MethodsCervical vaginal fluid (CVF) collected by a soft cup and high vaginal swabs (HVS) were obtained from PWLWH and HIV uninfected pregnant women (HUPW) at three antenatal time points. Maternal characteristics, combination antiretroviral therapy (cART) exposure, and pregnancy outcome were recorded. Concentrations of MMP-9, TIMP-1 and ten cytokines were measured by immunoassays. Vaginal microbiota composition was determined through 16S rRNA amplicon sequencing. MMP-9, TIMP-1 and cytokine concentrations were compared by HIV status, cART, and prematurity and in PWLWH correlations with polymorphonuclear leucocytes, cytokines and bacterial genera were explored.ResultsCVF was available for 50 PWLWH (108 samples) and 12 HUPW (20 samples) between gestation weeks 14-38. Thirty-six PWLWH conceived on cART and 14 initiated post-conception. There were five and one PTB outcomes in PWLWH and HUPW respectively. PWLWH had higher mean CVF concentrations of MMP-9 (p<0.001) and TIMP-1 (p=0.035) in the second trimester compared with HUPW with a similar trend in the third trimester. PWLWH also had higher CVF values of cytokines: IL-1β, IL-8, IL-12 and TNF-α in both trimesters compared to HUPW (p ≤ 0.003). In PWLWH, MMP-9 positively correlated with TIMP-1 (r=0.31, p=0.002) and CVF polymorphonuclear leucocytes (r=0.57, p=0.02). Correlations were observed between MMP-9 and three cytokines: IL-1β (r=0.61), IL-8 (r=0.57) and TNF-α (r=0.64), p<0.001, similarly for TIMP-1. Abundance of anaerobic pathobionts correlated with MMP-9: Gardnerella (r=0.44, p<0.001), Atopobium (r=0.33, p=0.005), and Prevotella genera (r=0.39, p<0.001). Conversely proportion of Lactobacillus genera negatively correlated with MMP-9 (rho=-0.46, p<0.001). MMP-9/TIMP-1 ratio increased with gestational age at sampling in PWLWH, but this was no longer significant after adjusting for confounders and no difference by prematurity was observed in this sub-study.ConclusionsHere we show strong correlations of MMP-9 to genital tract inflammation and sub-optimal bacterial genera in PWLWH indicating the ascending genital tract infection pathway may be a contributory mechanism to the high risk of PTB.

The objective: was to examine the effectiveness of treatment of late miscarriage threat by micronized form of progesterone for 100 mg – 3 times a day in the form of gelatin pills and vaginal tablets with lactose. Patients and methods. Under our supervision there were 70 pregnant women with normocenosis of vagina (NCV) without extragenital pathology, which were not performed systemic or local treatment with antibacterial drugs in the last 4 weeks. Among them 25 pregnant women with TLSM treated by gelatin tablets of micronized progesterone (GTP) (group 1); 25 pregnant women with TLSM, treated by vaginal micronized progesterone tablets (VPT) (2nd group) and 20 healthy women with physiological pregnancy – PV (control group). The distribution of women in the group adhered to the principles of randomization. The age of examined women ranged from 19 to 32 years, most pregnant women were aged under 30 years (89.02%). General clinical examination was carried out according to the standard scheme according to the Order MH of Ukraine № 620. Results. During the research we have determined the colpocytologcal dynamics and state of vaginal microbiota in pregnant women with threatened late miscarriage with initial vaginal normocenosis before and after treatment whit vaginal forms of progesterone. Conclusion. The received results showed low efficiency of micronized progesterone gelatin dragee at threat of the late miscarriage that at small therapeutic effect has led to the development of vaginal dysbiosis in all surveyed. In contrast, the use of micronized progesterone vaginal tablets – the maximally rapid therapeutic effect without disturbance of vaginal normocenosis. Key words: the threat of a late miscarriage, vaginal micronized forms of progesterone.

Summary This study aimed to determine the bacterial profile of vaginal samples from pregnant women and the prevalence of identified microorganisms. Materials and methods: A prospective epidemiological study was conducted on 150 pregnant women admitted to the Clinic of Obstetrics and Gynecology at Dr. G. Stranski University Hospital in Pleven. Vaginal secretion samples were collected from all the 150 women. Direct microscopy of native smears prepared by the wet mount method to detect Trichomonas vaginalis and direct microscopy of Gram-stained smears was performed. Aerobic culture studies were conducted to identify pathogenic bacteria and Sabouraud glucose agar (SGA) to detect the presence of Candida spp. Samples were also collected from 107 of the women for PCR tests for mycoplasma detection. Results: The highest relative share in the study was women aged 21 to 35 years 104 (69.33%). Of all the hospitalized and examined pregnant women, 87 (57.99%) had medical problems during the current pregnancy and postpartum complications, and 63 women (42%) gave birth without accompanying complications. In 86 (57.32%) of the women, bacteria were detected by direct microscopy of Gram-stained smears. Of these, 24 (16%) had gram-negative rods, 28 (18.66%) had gram-positive cocci. In 34 (22.66%), we found gram-negative and gram-variable pleomorphic bacteria. The aerobic culture study revealed microbiological growth in 44 (29.33%) of the women investigated. Conclusions: Studies on the profile of the vaginal microbiota in pregnant women and the spread of pathogenic microorganisms are essential for make prognoses for pregnancy outcome, evaluating the risk of developing a maternal-fetal infection, and discussing options for timely treatment.

Previous preterm delivery and maternal smoking are associated with increased risks of preterm delivery. It is not known whether gestational age at the time of a preterm delivery is correlated with gestational age in successive preterm deliveries and whether changes in smoking habits influence the subsequent risk of preterm delivery. We studied the associations among smoking habits, previous very preterm or moderately preterm delivery (before 32 weeks and at 32 to 36 weeks, respectively), and the risk of a subsequent very preterm or moderately preterm delivery in a population-based cohort of 243,858 women in Sweden between 1983 and 1993. The results were adjusted for covariates known to be associated with preterm delivery. The odds ratios for very or moderately preterm delivery in a subsequent pregnancy among women with a previous very preterm delivery, as compared with women who had a previous term delivery, were 12.4 (95 percent confidence interval, 9.1 to 17.0) and 7.1 (95 percent confidence interval, 6.0 to 8.4), respectively. Among women with a previous moderately preterm delivery, the corresponding odds ratios were 2.3 (95 percent confidence interval, 1.9 to 3.0) and 5.9 (95 percent confidence interval, 5.5 to 6.3), respectively. The odds ratios for a very preterm second delivery among the women who smoked 1 to 9 cigarettes per day and those who smoked 10 or more cigarettes per day, as compared with nonsmokers, were 1.4 (95 percent confidence interval, 1.1 to 1.7) and 1.6 (95 percent confidence interval, 1.3 to 2.0), respectively. The corresponding odds ratios for moderate preterm delivery were 1.3 (95% confidence interval, 1.2 to 1.4) and 1.5 (95 percent confidence interval, 1.4 to 1.6). The women who quit smoking between pregnancies were not at increased risk for very or moderately preterm delivery, whereas the women who started to smoke in the second pregnancy had the same risk as those who continued to smoke. The risk of a very preterm delivery in successive pregnancies is increased primarily among women with a previous very preterm delivery. Changes in smoking habits influence the risk of preterm delivery as well.

Torquetenovirus (TTV) is a nonpathogenic endogenous virus whose abundance varies with the extent of immune system activation. We determined if the TTV titer in the vagina of pregnant women was associated with vaginal microbiota composition and levels of compounds in vaginal secretions. Vaginal TTV and microbiota composition in 494 second trimester pregnant women were identified by gene amplification and analysis. Vaginal matrix metalloproteinases (MMPs), tissue inhibitors of MMP (TIMP) and lactic acid isomers were measured by ELISA. Dominance was defined as the relative abundance of a specific bacterium or species at >50% of the total number of bacteria identified. Clinical data were obtained by chart review. The median log10 TTV titer was lowest when Lactobacillus species other than L. iners were dominant (<1.0) as compared to when L. iners (4.1, p = 0.0001), bacteria other than lactobacilli (4.5, p = 0.0016) or no bacterium (4.7, p = 0.0009) dominated. The TTV titer was inversely proportional to L. crispatus abundance (p<0.0001) and directly proportional to levels of G. vaginalis (p = 0.0008) and L. iners (p = 0.0010). The TTV titer was proportional to TIMP-1, TIMP-2, MMP-8 and MMP-9 abundance (p≤0.0002) and inversely proportional to the level of D-lactic acid (p = 0.0024). We conclude that the association between variations in the TTV titer and the relative abundance of specific bacterial species and vaginal compounds indicates that local changes in immune status likely influence vaginal fluid composition.

STUDY QUESTIONDoes levothyroxine (LT4) treatment reduce adverse pregnancy outcomes in pregnant women with thyroid dysfunction?SUMMARY ANSWERLT4 treatment significantly reduces the risks of pregnancy loss, preterm delivery, and gestational hypertension, with no significant impacts on rates of live birth, placental abruption, or gestational diabetes.WHAT IS KNOWN ALREADYMultiple meta-analyses have examined the impact of LT4 on pregnancy outcomes, but quantitative confidence assessments are still lacking. Thus, an umbrella review is needed to systematically synthesize and assess the quality of this evidence.STUDY DESIGN, SIZE, DURATIONThis umbrella review of systematic reviews and meta-analyses used PubMed, Embase, Web of Science, and the Cochrane Database of Systematic Reviews. Searches included studies published in English or Chinese up to 20 March 2025.PARTICIPANTS/MATERIALS, SETTING, METHODSIncluded studies were systematic reviews or meta-analyses of randomized controlled trials assessing the effects of LT4 on pregnancy outcomes in women with subclinical hypothyroidism (SCH) or thyroid peroxidase antibody (TPOAb) positivity. A set of 24 associations across six pregnancy outcomes were analyzed: pregnancy loss, preterm delivery, live birth, placental abruption, gestational hypertension, and gestational diabetes. Methodological quality was assessed using AMSTAR 1, and evidence quality was graded using GRADE. Sensitivity analyses were conducted to confirm robustness.MAIN RESULTS AND THE ROLE OF CHANCEEleven meta-analyses were included. High-quality evidence showed that LT4 treatment reduced the risks of pregnancy loss (RR = 0.43; class III evidence), preterm delivery (RR = 0.56; class III evidence), and gestational hypertension (RR = 0.63; class IV evidence). Moderate-to-low-quality evidence indicated no significant impact on rates of live birth, placental abruption, or gestational diabetes. Of the 24 associations, 22 were rated as high confidence and two as medium confidence based on AMSTAR 1. Sensitivity analyses confirmed the robustness of the findings, but treatment effects varied according to the study population, treatment timing, and method. For pregnancy loss and preterm delivery outcomes, the risk was significantly reduced only when LT4 treatment was initiated in early pregnancy (pregnancy loss: RR = 0.60, P = 0.03; RR = 0.59, P = 0.003; preterm labor: RR = 0.58, P < 0.0001; RR = 0.46, P < 0.00001). Additionally, women with TSH levels greater than 4.0 mU/l derived greater benefits from LT4 treatment compared to those with TSH levels between 2.5 and 4.0 mU/l.LIMITATIONS, REASONS FOR CAUTIONLimitations include small sample sizes, potential biases (selection and reporting), and language restrictions to English and Chinese studies, which may affect generalizability.WIDER IMPLICATIONS OF THE FINDINGSBy integrating high-quality evidence, this study confirms that LT4 can reduce the risk of pregnancy loss and preterm delivery in pregnant women with thyroid dysfunction, supports its clinical application in specific populations, such as SCH patients with positive TPOAb or TSH > 4.0 mU/l, and warns against the risk of overtreatment. The results of this study provide an evidence base for clinical precision intervention. Future studies should address the heterogeneity through standardized large studies, clarify the dose threshold, and evaluate the long-term health effects of LT4 on mothers and infants, to further improve the guidelines and optimize risk stratification management.STUDY FUNDING/COMPETING INTEREST(S)This work was supported by the National Key R&D Program of China (Grant No. 2023YFC2508300, 2023YFC2508303, and 2023YFC2508305), the National Science and Technology Major Project (Grant No. 2024ZD0533403), and the National Natural Science Foundation of China (Grant No. 82100831, 81570709, and 82470826). All authors declared no competing interests.REGISTRATION NUMBERCRD42024586105.

To evaluate the risk of preterm delivery in patients with adenomyosis. A 1:2 nested case-control study. Tertiary-care institution. A base cohort population of 2138 pregnant women who attended routine prenatal check-up between July 1999 and June 2005. From this base cohort population, gravid women with singleton pregnancy who delivered prior to the completion of 37 weeks of gestation were identified and formed the study group. Singleton gravid women who had term delivery and who matched with age, body mass index, smoking, and status of previous preterm delivery were recruited concurrently and served as control group. Preterm delivery cases were further divided into spontaneous preterm delivery and preterm premature rupture of membranes (PPROM) cases. Risk analysis of preterm delivery between gravid women with and without adenomyosis. One-hundred and four preterm delivery case subjects and 208 control subjects were assessed. Overall, gravid women with adenomyosis were associated with significantly increased risk of preterm delivery (adjusted odds ratio 1.96, 95% CI 1.23-4.47, P=0.022). For subgroup analysis, gravid women with adenomyosis had an adjusted 1.84-fold risk of spontaneous preterm delivery (95% CI 1.32-4.31, P=0.012) and an adjusted 1.98-fold risk of PPROM (95% CI 1.39-3.15, P=0.017). Gravid women with adenomyosis were associated with increased risk of both spontaneous preterm delivery and PPROM. A common pathophysiological pathway may exist in these two disorders. Further in-depth biochemical and molecular studies are necessary to explore this phenomenon.

Maternal obesity increases the risk of preterm delivery. Obesity is known to be associated with altered lipid metabolism. To investigate the associations between high maternal triglyceride (mTG) levels during early pregnancy and risks of preterm delivery stratified by early pregnancy body mass index (BMI). Retrospective cohort study. University-based maternity center. 49,612 women with singleton pregnancy who underwent fasting serum lipid screening during early pregnancy. Risk of preterm delivery (total, <37 weeks; early, 28 to 33 weeks; and late, 34 to 36 weeks). Among women enrolled, 2494 had a preterm delivery, including 438 early preterm and 2056 late preterm delivery. High mTG (>90th percentile, 2.04 mM) was associated with shortened gestation. Risks of total, early, and late preterm deliveries increased with mTG levels, and the high mTG-related risk was highest for early preterm delivery [adjusted odds ratio (AOR) 1.72; 95% CI, 1.30 to 2.29]. After stratification by BMI, high mTG was associated with risk of preterm delivery in both overweight or obese (OWO) women (AOR 1.32; 95% CI, 1.02 to 1.70) and women with normal BMI (AOR 1.36; 95% CI, 1.16 to 1.59). In additional sensitivity analyses, we found that high mTG was related to higher risks of preterm delivery among OWO women and women with normal BMI (AOR, 1.54; 95% CI, 1.07 to 2.22 and 1.62, 1.34 to 1.96, respectively), especially early preterm delivery (AOR 2.47; 95% CI, 1.19 to 5.10, and AOR 2.50; 95% CI, 1.65 to 3.78, respectively). High mTG level during early pregnancy increased the risks of preterm delivery not only in OWO women but also in women with normal BMI.

Effective treatment of cervical intraepithelial neoplasia (CIN) can prevent invasive cervical cancer. The trend away from cold-knife conization toward more conservative procedures continues, but it is possible that excisional or ablative treatments might increase the risk of preterm delivery by lessening the mechanical support lent by a shortened cervix. These procedures also could impair local immunity by destroying glandular epithelium, and they might alter the bacterial flora in the cervicovaginal region. This retrospective cohort study, carried out at a colposcopy clinic in Auckland, New Zealand in the years 1988-2000, compared delivery outcomes in 652 women treated for CIN by laser conization, laser ablation, or a loop electrosurgical excision procedure (LEEP) and 426 untreated women. All participants carried a singleton pregnancy to at least 20 completed weeks of gestation. The overall rate of preterm delivery (before 37 weeks gestation) was 13.8%. The most common cause, identified in 45% of cases, was premature rupture of membranes (pPROM). Rates of total pretrerm deliveries, pPROM, and spontaneous preterm labor were higher in treated than in untreated women. Preterm delivery was iatrogenic in 2.9% of the treated group and 5.2% of the untreated group. Adjusted relative risk (aRR) figures showed that treating CIN was not associated with an increased risk of total or spontaneous preterm deliveries, but a single laser conization treatment or LEEP was associated with an increased risk of pPROM leading to preterm delivery. The risk of pPROM increased with an increasing height of excised cervical tissue. Women with a vertical cone height of at least 1.7 cm of tissue removed had a greater than 3-fold increase in risk of preterm delivery compared with untreated women (aRR, 3.6). The risk of pPROM increased linearly with increasing cone height; no threshold value was identified. The risk of all preterm deliveries increased significantly with increasing cone height. Treatment variables did not interact significantly with age, parity, or smoking during pregnancy, Mode of treatment did not relate to cone height. Women who are aware of the risk of preterm delivery associated with treating CIN will be likelier to present at an early stage for antibiotic and steroid treatment. Cervical cerclage might have a role in managing women whose ultrasound studies show progressive cervical shortening during pregnancy.

Background: Pregnant women living with HIV-infection(PWLWH) have elevated rates of preterm birth(PTB) in which HIV and combination-antiretroviral-therapy(cART) are implicated. PWLWH also have a high prevalence of adverse vaginal microbiota, which associate with genital-tract inflammation. The mechanism underlying PTB in PWLWH is unknown. We present the first data in PWLWH on genital-tract matrix-metalloproteinase-9(MMP-9), an important collagenase implicated in labour onset, and tissue-inhibitor-of-metalloproteinases-1(TIMP-1) and explore correlations with local inflammation and vaginal bacteria. Material and Methods: Cervical-vaginal fluid(CVF) collected by a soft cup and high vaginal swabs(HVS) were obtained from PWLWH and HIV uninfected pregnant women(HUPW) at three antenatal time-points. Maternal characteristics, cART exposure, and pregnancy outcome were recorded. Concentrations of MMP-9, TIMP-1 and ten cytokines were measured by immunoassays. Vaginal microbiota composition was determined through 16S rRNA-amplicon sequencing. MMP-9, TIMP-1 and cytokine concentrations were compared by HIV-status, cART, and prematurity and in PWLWH correlations with polymorphonuclear leucocytes, cytokines and bacterial genera were explored. Results: CVF was available for 50 PWLWH(108 samples) and 12 HUPW(20 samples) between gestation weeks 14-38. Thirty-six PWLWH conceived on cART and 14 initiated post-conception. There were five and one PTB outcomes in PWLWH and HUPW respectively. PWLWH had higher mean CVF concentrations of MMP-9(p<0.001) and TIMP-1(p=0.035) in the second trimester compared with HUPW with a similar trend in the third trimester. PWLWH also had higher CVF values of cytokines: IL-1alpha, IL-8, IL-12 and TNF-beta in both trimesters compared to HUPW (p≤0.003). In PWLWH, MMP-9 positively correlated with TIMP-1(r=0.31, p=0.002) and CVF polymorphonuclear leucocytes(r=0.57, p=0.02). Correlations were observed between MMP-9 and three cytokines: IL-1beta(r=0.61), IL-8(r=0.57) and TNF-alpha(r=0.64), p<0.001, similarly for TIMP-1. Abundance of anaerobic pathobionts correlated with MMP-9: Gardnerella(r=0.44, p<0.001), Atopobium(r=0.33, p=0.005), and Prevotella genera(r=0.39, p<0.001). Conversely proportion of Lactobacillus genera negatively correlated with MMP-9(rho=-0.46, p<0.001). MMP-9/TIMP-1 ratio increased with gestational age at sampling in PWLWH, but this was no longer significant after adjusting for confounders and no difference by prematurity was observed in this sub-study. Conclusions: Here we show strong correlations of MMP-9 to genital-tract inflammation and sub-optimal bacterial genera in PWLWH indicating the ascending genital-tract infection pathway may be a contributory mechanism to the high-risk of PTB.

Little is known about the mechanism and biochemical pathway of preterm delivery. Some drugs used to treat preterm labor are also useful for the treatment of primary dysmenorrhea. This study attempted to evaluate the association between primary dysmenorrhea and preterm delivery from an epidemiological perspective. A nested case-control study was conducted; 329 singleton preterm delivery cases were investigated, in aggregate and in subgroups (spontaneous preterm labor and preterm premature rupture of membranes). Concurrently, 329 singleton gravid women with term delivery served as controls. Medical charts and records provided information about the maternal history of dysmenorrhea, index pregnancy outcome, and demographic characteristics. Adjusted odds ratios (ORs) and 95% confidence intervals (CIs) were calculated using the multiple logistic regression method. Gravid women with a history of primary dysmenorrhea had no more risk of preterm delivery than those without a history of primary dysmenorrhea (adjusted OR, 1.16; 95% CI, 0.95 to 2.19; p=0.37). However, for subgroup analysis, gravid women with severe primary dysmenorrhea were associated with an adjusted 2.73-fold risk of spontaneous preterm delivery (95% CI, 1.49 to 4.95; p=0.02), and with an adjusted 1.51-fold risk of preterm premature rupture of membranes (95% CI, 0.68 to 3.22; p=0.31). Severe primary dysmenorrhea is associated with an increased risk of spontaneous preterm delivery. A common pathophysiologic pathway may exist between these two disorders. Further in-depth biochemical and molecular studies are necessary to explore this phenomenon.