Upregulated TIMP1 facilitates and coordinates myometrial contraction by decreasing collagens and cell adhesive capacity during human labor

Myometrial contraction is one of the key events involved in parturition. Increasing evidence suggests the importance of the extracellular matrix (ECM) in this process, in addition to the functional role of myometrial smooth muscle cells, and our previous study identified an upregulated tissue inhibitor of metalloproteinase 1 (TIMP1) in human laboring myometrium compared to nonlabor samples. This study aimed to further explore the potential role of TIMP1 in myometrial contraction. First, we confirmed increased myometrial TIMP1 levels in labor and during labor with cervical dilation using transcriptomic and proteomic analyses, followed by real-time PCR, western blotting, and immunohistochemistry. Then, a cell contraction assay was performed to verify the decreased contractility after TIMP1 knockdown in vitro. To further understand the underlying mechanism, we used RNA-sequencing analysis to reveal the upregulated genes after TIMP1 knockdown; these genes were enriched in collagen fibril organization, cell adhesion, and ECM organization. Subsequently, a human matrix metalloproteinase (MMP) array and collagen staining were performed to determine the TIMPs, MMPs and collagens in laboring and nonlabor myometrium. A real-time cell adhesion assay was used to detect cell adhesive capacity. The results showed upregulated MMP8 and MMP9, downregulated collagens, and attenuated cell adhesive capacity in laboring myometrium, while lower MMP levels and higher collagen levels and cell adhesive capacity were observed in nonlabor. Moreover, TIMP1 knockdown led to restoration of cell adhesive capacity. Together, these results indicate that upregulated TIMP1 during labor facilitates and coordinates myometrial contraction by decreasing collagen and cell adhesive capacity, which may provide effective strategies for the regulation of myometrial contraction.

Effects of two different types of luteal support on pregnancy outcomes following antagonist fresh embryo transfer: a retrospective study

BACKGROUND

Only a small number of studies have reported the use of progesterone vaginal gel in combination with dydrogesterone as part of the antagonist protocol for fresh embryo transfer. Therefore, this study aimed to compare the effects of two types of luteal support on pregnancy outcomes following the antagonist protocol for fresh embryo transfer.

METHODS

We performed a retrospective analysis of clinical data from infertile patients who underwent fresh embryo transfer via the antagonist protocol (2785 cycles) between February and July 2019 and between February and July 2021 at the Peking University Third Hospital Reproductive Medicine Centre. According to the luteal support received, the cycle groups were divided into the progesterone vaginal gel group (single medication or VP group; 1170 cycles) and the progesterone vaginal gel plus dydrogesterone group (combination medication or DYD + VP group; 1615 cycles). After propensity score matching, the clinical pregnancy, ongoing pregnancy, early miscarriage, and ectopic pregnancy rates were compared between the two groups.

RESULTS

In total, 1057 pairs of cycles were successfully matched via propensity scores. The clinical and ongoing pregnancy rates in the combination medication group were significantly higher than those in the single medication group (P < 0.05), whereas no significant differences were noted in the early miscarriage and ectopic pregnancy rates between the two groups (both P > 0.05).

CONCLUSIONS

Combined luteal support after the antagonist protocol is preferred for patients undergoing fresh cycle embryo transfer.

Quantitative analysis for grading uterine electromyography activities during labor

BACKGROUND

The strength of uterine contraction is one of the decisive factors for labor progression and parturition. Clinicians usually encounter difficulties in early identification of inadequate contractions and in oxytocin treatment. Electromyography-an emerging technology for uterine contraction monitoring-can quantify the intensity of myoelectric activity of uterine contraction. Therefore, grading patients with different uterine contraction intensities by electromyography is of great significance to the clinical intensive management of uterine contraction and labor process.

OBJECTIVE

This study aimed to quantify and grade electromyography activity during the latent phase of the first stage of labor and explore its relationship with oxytocin treatment and length of labor.

STUDY DESIGN

We performed a retrospective cohort study to identify electromyography parameters as a predictor for oxytocin treatment and length of labor among a cohort of term singleton primipara (n=508) during the latent phase who delivered in Guangzhou between August 2018 and December 2021. The electromyography parameters were graded according to the quartile method, and the significance of grading and delivery outcome was explored. Univariate and multivariate logistic regression were used to determine the predictors of oxytocin treatment.

RESULTS

Maternal gestational age (adjusted risk ratio, 1.2; 95% confidence interval, 1.0-1.5), root mean square (adjusted risk ratio, 0.01; 95% confidence interval, 0.004-0.03), and power (adjusted risk ratio, 0.02; 95% confidence interval, 0.01-0.05) were significant predictors of oxytocin argumentation. The low electromyography activity group had a longer first stage labor and total labor time and were more likely to use oxytocin.

CONCLUSION

Electromyography parameters root mean square and power had high predictive values for later oxytocin treatment among patients with spontaneous labor. Patients with low-grade electromyography were more likely need oxytocin treatment. Electromyography grading is very important for its clinical promotion and use, and it could lead to more reliable analyses of oxytocin treatments and eventually to more effective interventions to prevent prolonged labor.

Clinical Re-evaluation on Bioequivalence and Relative Bioavailability of Micronized Progesterone Hard Capsule (Yimaxin) and Micronized Progesterone Soft Capsule (Utrogestan) under Vaginal and Oral Administration Routes

Background and Objective:

To clinically re-evaluate relative bioavailability and bioequivalence of micronized progesterone (hard capsule) Yimaxin and micronized progesterone (soft capsule) Utrogestan under vaginal and oral administration routes.

Methods:

From December 2017 to June 2018, a total of 16 postmenopausal healthy women were recruited and received a total of four rounds of drug treatment with cross-over design, respectively Yimaxin and Utrogestan under vaginal and oral administration routes. Changes in the subjects’ hormone levels after medication were monitored and an endometrial biopsy after a course of treatment was performed in our hospital.

Result:

The Geomeans of AUC_0-t of Yimaxin and Utrogestan under vaginal administration route were 252.15 and 115.46, respectively, with a ratio of 2.19, and under oral administration route were 244.64 and 413.68, respectively, with a ratio of 0.59. The Geomeans of C_max of Yimaxin and Utrogestan under vaginal administration route were 28.11 and 12.21, respectively, with a ratio of 2.30, and under oral administration route were 53.12 and 129.85, respectively, with a ratio of 0.41.

Conclusion:

Yimaxin was not bioequivalent to Utrogestan. Yimaxin had higher exposure to the drug in vivo at the same dose when administered vaginally, and Utrogestan had higher exposure to the drug in vivo at the same dose when administered orally.

Vaginal Progesterone Supplementation in the Management of Preterm Labor: A Randomized Controlled Trial

OBJECTIVES

The primary objective in this study was to evaluate the effects of vaginal progesterone supplementation for the prolongation of the latency period in preterm labor. The secondary objectives were to evaluate gestational age at delivery, rates of preterm birth less than 34 and 37 weeks, obstetric outcomes, maternal compliance with medication use, and side effects.

METHODS

A randomized controlled, unblinded trial was performed. Ninety women with preterm labor occurring at 24 to 34 weeks were either randomized to a vaginal progesterone group (44 women) receiving tocolytic and antenatal corticosteroids treatment combined with vaginal micronized progesterone (400 mg everyday) or to the no-progesterone group (46 women) receiving tocolytic and antenatal corticosteroids treatment only.

RESULTS

Latency periods were more prolonged in the vaginal progesterone group than in the no-progesterone group (32.8 ± 18.7 vs. 25.8 ± 22.7 days, p = 0.045). Gestational age at delivery in the vaginal progesterone group was also higher than in the no-progesterone group (37 vs. 35 weeks, p = 0.027). There were significant reduction rates of preterm birth less than 34 weeks (13.6% vs. 39.1%, p = 0.012), low birth weight (29.5% vs. 50%, p = 0.048), neonatal respiratory distress syndrome (13.6% vs. 37%, p = 0.021), and neonatal intensive care unit admission (6.8% vs. 28.3%, p = 0.017).

CONCLUSIONS

Combined treatment with vaginal progesterone 400 mg could prolong the latency period in preterm labor when compared with no progesterone.

Efficacy of daily rectal micronized progesterone for prevention of preterm delivery: a randomized clinical trial

Introduction: Preterm delivery is the leading cause of neonatal morbidity and mortality and its prevention is always under serious concern.Objective: The aim of the present study was to determine the efficacy of rectal progesterone as a maintenance tocolytic after arresting preterm labor, for increasing the duration of pregnancy, and postponing preterm birth.Method: The study was performed as a double blind randomized clinical trial on women with preterm labor in whom contractions have been stopped. The eligible women were randomly divided into two groups. In the intervention group (progesterone group), progesterone was administered rectally as a dose of 200 mg daily until 36⁺⁶weeks or spontaneous delivery before that time, whichever came first; and in the placebo group, placebo was administered in a similar manner. Primary outcomes were number of deliveries before 37 weeks of gestation and time to delivery interval in two groups. Secondary outcomes were neonatal Apgar score and weight, and need for NICU admission.Results: 160 women finished the study (80 women in each group). The women of the two groups did not have significant difference according to the baseline characteristics. Frequency of preterm labor (earlier than 37 weeks) and mean gestational age at the time of delivery did not show significant difference in two groups. Also, neonatal outcome including Apgar score, birth weight, NICU admission and neonatal complications were not different between the two groups. The pregnancy length was longer in progesterone group (28.84 ± 3.36 VS 21.19 ± 4.62 days), [p = .001, CI 95%: 3.71-4.83]. The time-to-event (delivery) analysis showed a hazard ratio of 1.02 (95% CI 0.36-2.77).Conclusion: Rectal progesterone at a daily dose of 200 mg as a maintenance tocolytic agent, cannot lower the frequency of preterm delivery but was suggested to prolong pregnancy length.

Progesterone - Effective for Tocolysis and Maintenance Treatment After Arrested Preterm Labour?: Critical Analysis of the Evidence

Numerous experimental studies indicate that natural progesterone, through various mechanisms, exerts an inhibitory effect on uterine contractility and sensitises the myometrium for tocolytics. It was therefore appropriate to investigate the possible benefits of oral/vaginal progesterone and the synthetic progesterone derivative 17-α-hydroxyprogesterone caproate, applied intramuscularly, in clinical studies on primary tocolysis, additively to established tocolytics ("adjunctive tocolysis") and as maintenance treatment after successful tocolysis in cases of threatened preterm birth. Three studies with a small number of cases do not yield any sufficient evidence for recommending progesterone/17-α-hydroxyprogesterone caproate as primary tocolysis in women with preterm labour. There is also no evidence that progesterone or 17-α-hydroxyprogesterone caproate combined with commonly used tocolytics leads to a prolongation of pregnancy and a significant decrease in the rate of preterm birth. The data on the use of progesterone as maintenance treatment is controversial. While randomised, controlled studies with low quality showed promising results, studies with high quality did not reveal any significant differences with regard to the rate of preterm birth < 37 weeks of gestation, the latency period until delivery and in the neonatal outcome between progesterone/17-α-hydroxyprogesterone caproate and placebo or no treatment. Significant differences in the methodology, the inclusion and outcome criteria, the mode of application and the dosages of the substances as well as the inadequate statistical power as a result of low numbers of cases make interpretation and comparability of the studies difficult. Therefore, well-designed randomised, placebo-controlled, double-blind studies with uniform primary outcome criteria are needed in order to clarify whether progesterone and via which route of administration and at which dosage is of clinical benefit for patients with manifest preterm contractions and as maintenance treatment after arrested preterm labour.