暂无摘要。

At present, the success of non-surgical embryo recovery (NSER) and transfer (NSET) hinges upon the cervical passage of catheters, but penetration of the uterine cervix in ewes is problematic due to its anatomical structure (i.e., long and narrow cervical lumen with misaligned folds and rings). It is a major obstacle limiting the widespread application of NSER and NSET in sheep. While initial attempts to traverse the uterine cervix focused on adapting or re-designing insemination catheters, more recent studies demonstrated that cervical relaxation protocols were instrumental for transcervical penetration in the ewe. An application of such protocols more than tripled cervical penetration rates (currently at 90-95 %) in sheep of different breeds (e.g., Dorper, Lacaune, Santa Inês, crossbred, and indigenous Brazilian breeds) and ages/parity. There is now sufficient evidence to suggest that even repeatedly performed cervical passages do not adversely affect overall health and reproductive function of ewes. Despite these improvements, appropriate selection of donors and recipients remains one of the most important requirements for maintaining high success rates of NSER and NSET, respectively. Non-surgical ovine embryo recovery has gradually become a commercially viable method as even though the procedure still cannot be performed by untrained individuals, it is inexpensive, yields satisfactory results, and complies with current public expectations of animal welfare standards. This article reviews critical morphophysiological aspects of transcervical embryo flushing and transfer, and the prospect of both techniques to replace surgical methods for multiple ovulation and embryo transfer (MOET) programs in sheep. We have also discussed some potential pharmacological and technical developments in the field of non-invasive embryo recovery and deposition.

OBJECTIVE: The aim of the present study was to investigate the effects of epidural analgesia (EA) administered at cervical dilatation of 1 cm on multiparae who underwent vaginal delivery.
METHODS: This propensity score-matched retrospective cohort research was conducted between 2021 and 2022. All the singleton multiparae who had previous successful vaginal deliveries and epidural analgesia during this delivery were screened for eligibility. The primary outcome was the effect of EA on the duration of labor. The main secondary outcomes included the incidence of cesarean delivery and umbilical arterial pH.
RESULTS: This study incorporated 686 multiparae who were divided into two cohorts: EA 1 (cervical dilatation = 1 cm, n = 166) and EA 2 (cervical dilatation >1 cm, n = 520). In the propensity score-matched cohort (including 164 women in each group), there were no statistically significant differences in the incidence of cesarean delivery (4 [2.4%] vs 4 [2.4%], P = 1.000), umbilical arterial pH (7.28 ± 0.06 vs 7.28 ± 0.07, P = 0.550) and other secondary outcomes between the two groups. Based on a comparative assessment of the women who delivered vaginally to the Kaplan-Meier curves and propensity score-matching (including 160 women in each group), there was no statistical significance in the duration of the first, second and third stages of labor (log rank P, P = 0.811; P = 0.413; P = 0.773, respectively).
CONCLUSIONS: Initiation of epidural analgesia at cervical dilatation of 1 cm in multiparae did not cause adverse effects with regard to the duration of labor, increased cesarean deliveries, and bad neonatal outcomes.

Successful pregnancy highly depends on the complex interaction between the uterine body, cervix, and fetal membrane. This interaction is synchronized, usually following a specific sequence in normal vaginal deliveries: (1) cervical ripening, (2) uterine contractions, and (3) rupture of fetal membrane. The complex interaction between the cervix, fetal membrane, and uterine contractions before the onset of labor is investigated using a complete third-trimester gravid model of the uterus, cervix, fetal membrane, and abdomen. Through a series of numerical simulations, we investigate the mechanical impact of (i) initial cervical shape, (ii) cervical stiffness, (iii) cervical contractions, and (iv) intrauterine pressure. The findings of this work reveal several key observations: (i) maximum principal stress values in the cervix decrease in more dilated, shorter, and softer cervices; (ii) reduced cervical stiffness produces increased cervical dilation, larger cervical opening, and decreased cervical length; (iii) the initial cervical shape impacts final cervical dimensions; (iv) cervical contractions increase the maximum principal stress values and change the stress distributions; (v) cervical contractions potentiate cervical shortening and dilation; (vi) larger intrauterine pressure (IUP) causes considerably larger stress values and cervical opening, larger dilation, and smaller cervical length; and (vii) the biaxial strength of the fetal membrane is only surpassed in the cases of the (1) shortest and most dilated initial cervical geometry and (2) larger IUP.

The diagnosis of failure to progress, the most common indication for intrapartum cesarean delivery, is based on the assessment of cervical dilation and station over time. Labor curves serve as references for expected changes in dilation and fetal descent. The labor curves of Friedman, Zhang et al, and others are based on time alone and derived from mothers with spontaneous labor onset. However, labor induction is now common, and clinicians also consider other factors when assessing labor progress. Labor curves that consider the use of labor induction and other factors that influence labor progress have the potential to be more accurate and closer to clinical decision-making.
This study aimed to compare the prediction errors of labor curves based on a single factor (time) or multiple clinically relevant factors using two modeling methods: mixed-effects regression, a standard statistical method, and Gaussian processes, a machine learning method.
This was a longitudinal cohort study of changes in dilation and station based on data from 8022 births in nulliparous women with a live, singleton, vertex-presenting fetus ≥35 weeks of gestation with a vaginal delivery. New labor curves of dilation and station were generated with 10-fold cross-validation. External validation was performed using a geographically independent group. Model variables included time from the first examination in the 20 hours before delivery; dilation, effacement, and station recorded at the previous examination; cumulative contraction counts; and use of epidural anesthesia and labor induction. To assess model accuracy, differences between each model\'s predicted value and its corresponding observed value were calculated. These prediction errors were summarized using mean absolute error and root mean squared error statistics.
Dilation curves based on multiple parameters were more accurate than those derived from time alone. The mean absolute error of the multifactor methods was better (lower) than those of the single-factor methods (0.826 cm [95% confidence interval, 0.820-0.832] for the multifactor machine learning and 0.893 cm [95% confidence interval, 0.885-0.901] for the multifactor mixed-effects method and 2.122 cm [95% confidence interval, 2.108-2.136] for the single-factor methods; P<.0001 for both comparisons). The root mean squared errors of the multifactor methods were also better (lower) than those of the single-factor methods (1.126 cm [95% confidence interval, 1.118-1.133] for the machine learning [P<.0001] and 1.172 cm [95% confidence interval, 1.164-1.181] for the mixed-effects methods and 2.504 cm [95% confidence interval, 2.487-2.521] for the single-factor [P<.0001 for both comparisons]). The multifactor machine learning dilation models showed small but statistically significant improvements in accuracy compared to the mixed-effects regression models (P<.0001). The multifactor machine learning method produced a curve of descent with a mean absolute error of 0.512 cm (95% confidence interval, 0.509-0.515) and a root mean squared error of 0.660 cm (95% confidence interval, 0.655-0.666). External validation using independent data produced similar findings.
Cervical dilation models based on multiple clinically relevant parameters showed improved (lower) prediction errors compared to models based on time alone. The mean prediction errors were reduced by more than 50%. A more accurate assessment of departure from expected dilation and station may help clinicians optimize intrapartum management.

Non-surgical embryo recovery (NSER) is usually preceded by a cervical relaxation in ovine donors, based on estradiol benzoate (EB), prostaglandin (PGF), and oxytocin (OT). However, it is hypothesized that, due to poorly understood mechanisms, EB can result in embryotoxic actions. To evaluate this, 20 min before NSER superovulated sheep were induced to cervical relaxation with 0.0 (G0.0), 0.5 (G0.5), or 1.0 mg (G1.0) of EB associated with 37.5 μg of PGF 16 h before NSER and 50 IU of OT. In doing so, the efficiency and duration of the NSER procedure showed no compromise (P > 0.05). Additionally, the presence of EB did not affect (P > 0.05) the embryo\'s morphological quality, the development dynamics, or the abundance of transcripts associated with embryonic quality (OCT4 and NANOG), cellular stress (HSP90 and PRDX1), and apoptosis (BCL2 and BAX). A similar result (P > 0.05) was also observed when comparing embryonic cryosurvival at 24 (52.0, 52.0, and 54.0) and 48 h (60.0, 54.0, and 58.0) of in vitro culture (G0.0, G0.5, and G1.0, respectively). Thus, we can conclude that EB use does not compromise embryonic quality and cryoresistance.

BACKGROUND: To identify the effect and optimal time of cervical cerclage in asymptomatic twin pregnancies with cervical shortening or dilation.
METHODS: This observational retrospective study enrolled all women with asymptomatic twin pregnancies who were diagnosed with asymptomatic cervical shortening or dilation at the Second Affiliated Hospital of Wenzhou Medical University between 2010 and 2022. Women included were allocated into the cerclage group (n = 36) and the no cerclage group (n = 22). The cerclage group was further divided into the cerclage group (< 24 weeks group) and the cerclage group (24-28 weeks group) according to the time of cerclage. The no cerclage group was further divided into no cerclage group (< 24 weeks group) and no cerclage group (24-28 weeks group) according to the time of ultrasound-indicated or physical exam indicated cerclage. The rates of PTB < 24, 28, 32 and 34 weeks of gestation, maternal and neonatal outcomes were compared among the groups.
RESULTS: The gestational age (GA) at delivery was higher (P = 0.005) and the interval time between the presentation of the indicated cerclage and delivery was longer in the cerclage group (P < 0.001). The rates of PTB before 28, 32, and 34 weeks of gestation, caesarean section and stillbirth were lower in the cerclage group (P < 0.05). The birthweight of the twins was higher in the cerclage group (P = 0.012). Admissions to the NICU were more frequent in pregnancies with no cerclage (P = 0.008). Subgroup analysis showed that the interval time between the presentation and delivery was longer in the cerclage group (< 24 weeks) (P < 0.001). The GA at delivery and the birthweight of the twins were significantly higher in the cerclage group (< 24 weeks) (P < 0.001). No differences were found in the GA at presentation, the GA at delivery, the interval time between the presentation to delivery and birthweight between the cerclage group (24-28 weeks group) and the control group (24-28 weeks group) (P > 0.05).
CONCLUSIONS: Cerclage appears to prolong the GA at delivery and the interval time between the presentation to delivery, and may reduce the incidence of PTB before 28, 32 and 34 weeks of gestation and adverse perinatal outcomes in asymptomatic twin pregnancies with cervical shortening or dilation. Cerclage before 24 weeks of gestation showed longer GA at delivery, longer interval time between the presentation to delivery and higher birthweight of the twins. The GA at presentation, the GA at delivery, the interval time between the presentation to delivery and birthweight in women with cerclage at 24-28 weeks were similar to those in women without cerclage at 24-28 weeks.

OBJECTIVE: This retrospective cohort study aimed to assess the efficacy of emergency cervical cerclage (ECC) performed with the combined McDonald-Shirodkar technique in twin pregnancies between 18 and 26 weeks of pregnancy with painless cervical dilation 1 to 6 cm.
METHODS: A retrospective cohort study matched with the degree of cervical dilation was conducted. The study group (case group) included women with twin pregnancies undergoing combined McDonald-Shirodkar approach with cervical dilation ≥1 cm between 18 to 26 weeks of gestation at four institutions, from December 2015 to December 2022. To minimize confounding factors, we elucidated the causality structure using a directed acyclic graph and performed 1:1 case-control matching. A control group underwent the McDonald approach. The primary outcome was gestational age (GA) at delivery. The secondary outcomes were pregnancy latency; the rates of spontaneous preterm birth at <28, <30, <32, and <34 weeks; and neonatal outcomes. Additional subanalysis was performed by dividing the patients into two subgroups of women with cervical dilation ≥3 cm and <3 cm.
RESULTS: A total of 84 twin pregnancies were managed with either the combined McDonald-Shirodkar approach (case group: n = 42) or the McDonald approach (control group: n = 42). Demographic characteristics were not significantly different in the two groups (P > 0.05). After adjusting for confounders that were represented by a directed acyclic graph, median GA at delivery was significantly higher (30.5 vs 27 weeks; Bate: 3.40 [95% confidence interval (CI), 2.13-4.67], P < 0.001) and median pregnancy latency was significantly longer (56 vs 28 days; Bate: 24.04 [95% CI, 13.31-34.78], P < 0.001) in the case group compared with the control group. Rates of spontaneous preterm birth at <28, <30, <32, and <34 weeks were significantly lower in the case group than in the control group. For neonatal outcomes, there was higher birth weight (1543.75 vs 980 g; Bate: 420.08 [95% CI, 192.18-647.98], P < 0.001) and significantly lower overall perinatal mortality (7.1% vs 31%; adjusted odds ratio, 0.16 [95% CI, 0.04-0.70], P = 0.014) in the case group compared with the control group. When cervical dilation was ≥3 cm, the combined McDonald-Shirodkar procedure can significantly reduce perinatal mortality (8.3% vs 46.7%; adjusted odds ratio, 0.09 [95% CI, 0.01-0.77], P = 0.028), significantly decrease the risk of delivery at <28 and <30 weeks, and prolong GA at delivery and pregnancy latency compared with the McDonald procedure.
CONCLUSIONS: ECC performed with the combined McDonald-Shirodkar procedure in women with twin pregnancies who have cervical dilation 1 to 6 cm in midtrimester pregnancy may reduce the rate of spontaneous preterm birth and improve perinatal and neonatal outcomes compared with the McDonald procedure, especially for twin pregnancies in women with cervical dilation of 3 to 6 cm and prolapsed membranes.

Artificial insemination (AI) and in vivo embryo production (or multiple ovulation and embryo transfer, MOET) programs are both instrumental in accelerating the propagation of genetically and economically superior goats and sheep. The aim of this review was to present the current gestalt of non-surgical AI and embryo recovery (NSER) procedures in small ruminants. Small body size, precluding rectal palpation, and highly limited penetrability of the uterine cervix in ewes are the major reasons for the scarce use of non-surgical assisted reproduction techniques in this species. As a result, AI and embryo recovery techniques in sheep mainly involve laparoscopy or laparotomy (LAP). In does, however, the Embrapa method of AI allows for successful intrauterine deposition of semen, resulting in pregnancy rates from 50 to 80% under field conditions (>3 000 goats inseminated) when frozen-thawed semen is used. After the administration of prostaglandin F2α (PGF2α), non-surgical (transcervical) embryo recovery is also feasible in goats, with the cervical penetration rate approaching 100%. There is a paucity of information on the efficacy of non-surgical AI using frozen semen in sheep, but the results are satisfactory with fresh, cooled, or chilled ram semen. An application of the NSER technique in ewes has greatly improved over the last decade, and cervical penetration rates of ∼90% can be achieved when a hormonal cervical dilation protocol using PGF2α, oxytocin, and/or estradiol ester (e.g., estradiol benzoate) is applied. In some genotypes of sheep, sufficient cervical dilation can be induced without estradiol ester included in the protocol. Several studies indicated that recovery of transferable quality ovine embryos using NSER is comparable to that employing a ventral midline laparotomy, and NSER is evidently a method of choice when animal welfare is concerned. Considering both the number of retrievable embryos and animal well-being, the NSER is a viable alternative for surgical procedures. With further developments, it has the makings of a primary, if not exclusive, embryo recovery technique in small ruminants worldwide.

OBJECTIVE: To explore the effects of labor analgesia for primiparae with different stages of cervical dilation on parturition and neonates.
METHODS: In the past three years, 530 cases of primiparae who had delivered in the Second People\'s Hospital of Hefei and were eligible for a vaginal trial of parturition were enrolled as the research subjects. Of these, 360 puerperae had labor analgesia, and the remaining 170 were taken as the control group. Those given labor analgesia were divided into three groups based on the different stages of cervical dilation at that time. There were 160 cases in Group I (cervical dilation <3 cm), 100 cases in Group II (cervical dilation of 3-4 cm), and 100 cases in Group III (cervical dilation of 4-6 cm). The labor and neonatal outcomes were compared among the four groups.
RESULTS: The first, second, and total stages of labor in the three groups receiving labor analgesia were all longer than in the control group, and the differences were statistically significant (p < 0.05 in all). Group I had the longest duration of each stage and the total stage of labor. The differences in labor stages and the total stage of labor were not statistically significant between Group II and Group III (P > 0.05). In the three groups with labor analgesia, the usage rate of oxytocin was higher than in the control group, and the differences were statistically significant (P < 0.05). The differences in the incidence of postpartum hemorrhage, the incidence of postpartum urine retention, and the episiotomy rate were not statistically significant among the four groups (P > 0.05). The differences in the neonatal Apgar score were not statistically significant among the four groups (P > 0.05).
CONCLUSIONS: Labor analgesia might prolong the stages of labor but does not affect the neonatal outcomes. It would be optimal to conduct labor analgesia when cervical dilation reaches 3-4 cm.