The second stage of labor

Duration time of labor progression for pregnant women of vaginal birth after cesarean in Hubei, China

OBJECTIVE

There have been limited reports on the duration of labor progression in pregnant women undergoing vaginal birth after cesarean (VBAC). This study aimed to investigate the duration of labor progression during VBAC in Hubei, China.

METHODS

A total of 359 pregnant women undergoing VBAC were enrolled as the VBAC group, meeting the following criteria: singleton pregnancy, gestational age ≥ 37 weeks, live birth, history of cesarean delivery, and a willingness to attempt a vaginal delivery. At the same time, 359 primiparas successfully undergoing vaginal delivery were randomly enrolled in the control group at a 1:1 ratio. Subsequently, the durations of the first, second, and third stages of labor were comparatively analyzed between the two groups.

RESULTS

The duration of the first, second, and total stages of labor in the VBAC group was significantly shorter than that in the control group (p < 0.05). There was no significant difference in the duration of the third stage of labor between the two groups (p > 0.05). The amount of blood loss, the rate of postpartum hemorrhage (PPH), and episiotomy were higher in the VBAC group than in the control group (p < 0.05). The rate of labor analgesia and intrapartum fever in the VBAC group was significantly lower than that in the control group (p < 0.05).

CONCLUSION

The duration of labor progression of the first, second, and total stages of VBAC is shorter than that in primiparous women in our observation in China.

Efficacy of different strategies for reducing labor pain: A Bayesian analysis

BACKGROUND

The effectiveness of different medical interventions in managing labor pain has yielded mixed results. Therefore, this systematic review and network meta-analysis aimed to provide a comprehensive summary of the available evidence on the impact of different strategies for reducing labor pain.

METHODS

We systematically searched 3 English databases (Pubmed, Embase and the Cochrane Library) from inception to January 2023. Randomized controlled trials (RCTs) or controlled clinical trials that investigating the effects of different strategies for reducing labor pain were included in this network meta-analysis. Risk of bias (ROB) was assessed using the Cochrane ROB tools. Network meta-analysis was performed using the R software (version 4.2.1) with gemtc package.

RESULTS

A total of 9 studies involving 823 patients, including 9 treatments (acupressure, birth ball exercise, Bonapace method, distraction techniques, ice pressure, LI4 acupressure, lidocaine spray, smartphone-based music intervention and placebo). The surface under the cumulative ranking (SUCRA) shows that Bonapace method ranked first (SUCRA, 79.5%), LI4 acupressure ranked second (SUCRA, 65.6%), distraction technique ranked third (SUCRA, 57.6%), birth ball exercise ranked fourth (SUCRA, 51.8%).

CONCLUSIONS

According to the results of the network meta-analysis, among the different strategies examined, the Bonapace Method stands out as the most effective nonpharmacological intervention for reducing labor pain. The results of this meta-analysis can aid both patients and healthcare professionals in choosing the most effective techniques to reduce labor pain.

Human development and reproduction in space-a European perspective

This review summarises key aspects of the first reproductive and developmental systems Science Community White Paper, supported by the European Space Agency (ESA). Current knowledge regarding human development and reproduction in space is mapped to the roadmap. It acknowledges that sex and gender have implications on all physiological systems, however, gender identity falls outside the scope of the document included in the white paper collection supported by ESA. The ESA SciSpacE white papers on human developmental and reproductive functions in space aim to reflect on the implications of space travel on the male and female reproductive systems, including the hypothalamic-pituitary-gonadal (HPG) reproductive hormone axis, and considerations for conception, gestation and birth. Finally, parallels are drawn as to how this may impact society as a whole on Earth.

The Pathophysiology of Labor Dystocia: Theme with Variations

Abnormally prolonged labor, or labor dystocia, is a common complication of parturition. It is the indication for about half of unplanned cesarean deliveries in low-risk nulliparous women. Reducing the rate of unplanned cesarean birth in the USA has been a public health priority over the last two decades with limited success. Labor dystocia is a complex disorder due to multiple causes with a common clinical outcome of slow cervical dilation and fetal descent. A better understanding of the pathophysiologic mechanisms of labor dystocia could lead to new clinical opportunities to increase the rate of normal vaginal delivery, reduce cesarean birth rates, and improve maternal and neonatal health. We conducted a literature review of the causes and pathophysiologic mechanisms of labor dystocia. We summarize known mechanisms supported by clinical and experimental data and newer hypotheses with less supporting evidence. We review recent data on uterine preparation for labor, uterine contractility, cervical preparation for labor, maternal obesity, cephalopelvic disproportion, fetal malposition, intrauterine infection, and maternal stress. We also describe current clinical approaches to preventing and managing labor dystocia. The variation in pathophysiologic causes of labor dystocia probably limits the utility of current general treatment options. However, treatments targeting specific underlying etiologies could be more effective. We found that the pathophysiologic basis of labor dystocia is under-researched, offering wide opportunities for translational investigation of individualized labor management, particularly regarding uterine metabolism and fetal position. More precise diagnostic tools and individualized therapies for labor dystocia might lead to better outcomes. We conclude that additional knowledge of parturition physiology coupled with rigorous clinical evaluation of novel biologically directed treatments could improve obstetric quality of care.

Term breech presentation vaginal births in Tibet: A retrospective analysis of 451 cases

Background

In high altitude areas, like Tibet, most fetuses in breech presentation at term are delivered vaginally owing to a variety of reasons, but this has not been published.

Objective

This study aimed to provide references and evidence for the delivery of breach presentation term fetuses in high altitude areas, through comparing and analyzing the data of full-term singleton fetuses with breech or cephalic presentation in Naqu People's Hospital, Tibet.

Study design

We retrospectively analyzed the clinical data of 451 breech presentation fetuses mentioned above over a period of 5  years (2016-2020). A total of 526 cephalic presentation fetuses' data within 3  months (1 June to 1 September 2020) of the same period were collected too. Statistics were compared and assembled on fetal mortality, Apgar scores, and severe neonatal complications for both planned cesarean section (CS) and vaginal delivery. In addition, we also analyzed the types of breech presentation, the second stage of labor, and damage to the maternal perineum during vaginal delivery.

Results

Among the 451 cases of breech presentation fetuses, 22 cases (4.9%) elected for CS and 429 cases (95.1%) elected for vaginal delivery. Of the women who chose vaginal trial labor, 17 cases underwent emergency CSs. The perinatal and neonatal mortality rate was 4.2% in the planned vaginal delivery group and the incidence of severe neonatal complications was 11.7% in the transvaginal group, no deaths were detected in the CS group. Among the 526 cephalic control groups with planned vaginal delivery, the perinatal and neonatal mortality was 1.5% (p = 0.012), and the incidence of severe neonatal complications was 1.9%. Among vaginal breech deliveries, most of them were complete breech presentation (61.17%). Among the 364 cases, the proportion of intact perinea was 45.1%, and first degree lacerations accounted for 40.7%.

Conclusion

In the Tibetan Plateau region, vaginal delivery was less safe than cephalic presentation fetuses for full-term breech presentation fetuses delivered in the lithotomy position. However, if dystocia or fetal distress can be identified in time and then encouraged to convert to cesarean, its safety will be greatly improved.

Out of step societal and Darwinian adaptation during evolution is the cause of multiple women's health issues

During human evolution, major changes in our societal conditions and environment took place without sufficient time for concomitant genetic alterations, leading to out of step adaptation and diseases in women. We first discuss recent societal adaptation mismatch (menstrual bleeding; increases in cancers of reproductive organs, endometriosis; mother's nursing; polycystic ovarian syndrome; transgenerational epigenetic modifications), followed by Darwinian out of step adaptation (labor difficulties; sex chromosomes, human diseases and sex disparity in genomic DNA). We discuss the evolutionary basis of menstrual bleeding, followed by recent increases in cancers of reproductive organs and endometriosis. The importance of breastfeeding by mothers is also emphasized. Earlier onset of menarche, decreased rates of childbirths and breastfeeding resulted in increased number of menstrual cycles in a lifetime, coupled with excess estrogen exposure and incessant ovulation, conditions that increased the susceptibility to mammary and uterine cancers as well as ovarian epithelial cancer and endometriosis. Shorter lactation duration in mothers also contributed to more menstrual cycles. We further discuss the evolutionary basis of the prevalent polycystic ovary syndrome. During the long-term Darwinian evolution, difficulties in childbirth evolved due to a narrowed pelvis, our upright walking and enlarged fetal brain sizes. Because there are 1.5% genomic DNA differences between woman and man, it is of significance to investigate sex-specific human physiology and diseases. In conclusion, understanding out of step adaptation during evolution could allow the prevention and better management of female reproductive dysfunction and diseases.

Assessing maternal thyroid function and its relationship to duration of the first stage of labor

INTRODUCTION

Maternal thyroid function plays a critical role in the normal labor process. Whether maternal thyroid function affects the duration of the first stage of labor is still unknown.

METHODS

Maternal serum levels of free thyroxine (FT4), thyroid-stimulating hormone (TSH) and thyroid peroxidase antibody (TPOAb) were detected in 31,382 pregnant women. A multiple linear regression model was applied to investigate the effect of maternal thyroid function on the duration of the first stage of labor.

RESULTS

FT4 level in the second trimester and in the third trimester was found to be negatively associated with duration of the first stage of labor (β = -1.30 h, 95% CI: -2.28, -0.32, P < 0.01; β = -0.35 h, 95% CI: -0.61, -0.10, P < 0.01). TSH level in the third trimester was found to be positively associated with the duration of the first stage of labor (β = 0.12 h, 95% CI: 0.06, 0.18, P < 0.001). Per unit increase in TPOAb (IU/mL) in the second trimester and in the third trimester was significantly associated with prolonged first stage of labor (β = 0.08 h, 95% CI: 0.01, 0.14, P = 0.02; β = 0.09 h, 95% CI: 0.02, 0.15, P = 0.01). For pregnant women suffering from subclinical hypothyroidism combined without TPOAb, TSH level in the third trimester exhibited a significant positive association with the length of the first stage of labor (β = 2.44 h, 95% CI: 0.03, 4.84, P = 0.04).

CONCLUSIONS

These findings suggest that maternal FT4, TSH and TPOAb might be important predictors of the first stage of labor.

On the management of maternal pushing during the second stage of labor: a biomechanical study considering passive tissue fatigue damage accumulation

BACKGROUND

During the second stage of labor, the maternal pelvic floor muscles undergo repetitive stretch loading as uterine contractions and strenuous maternal pushes combined to expel the fetus, and it is not uncommon that these muscles sustain a partial or complete rupture. It has recently been demonstrated that soft tissues, including the anterior cruciate ligament and connective tissue in sheep pelvic floor muscle, can accumulate damage under repetitive physiological (submaximal) loads. It is well known to material scientists that this damage accumulation can not only decrease tissue resistance to stretch but also result in a partial or complete structural failure. Thus, we wondered whether certain maternal pushing patterns (in terms of frequency and duration of each push) could increase the risk of excessive damage accumulation in the pelvic floor tissue, thereby inadvertently contributing to the development of pelvic floor muscle injury.

OBJECTIVE

This study aimed to determine which labor management practices (spontaneous vs directed pushing) are less prone to accumulate damage in the pelvic floor muscles during the second stage of labor and find the optimum approach in terms of minimizing the risk of pelvic floor muscle injury.

STUDY DESIGN

We developed a biomechanical model for the expulsive phase of the second stage of labor that includes the ability to measure the damage accumulation because of repetitive physiological submaximal loads. We performed 4 simulations of the second stage of labor, reflecting a directed pushing technique and 3 alternatives for spontaneous pushing.

RESULTS

The finite element model predicted that the origin of the pubovisceral muscle accumulates the most damage and so it is the most likely place for a tear to develop. This result was independent of the pushing pattern. Performing 3 maternal pushes per contraction, with each push lasting 5 seconds, caused less damage and seemed the best approach. The directed pushing technique (3 pushes per contraction, with each push lasting 10 seconds) did not reduce the duration of the second stage of labor and caused higher damage accumulation.

CONCLUSION

The frequency and duration of the maternal pushes influenced the damage accumulation in the passive tissues of the pelvic floor muscles, indicating that it can influence the prevalence of pelvic floor muscle injuries. Our results suggested that the maternal pushes should not last longer than 5 seconds and that the duration of active pushing is a better measurement than the total duration of the second stage of labor. Hopefully, this research will help to shed new light on the best practices needed to improve the experience of labor for women.

Effects of non-pharmacological coping strategies for reducing labor pain: A systematic review and network meta-analysis

BACKGROUND

Facilitating the childbirth process is a global issue. Many strategies have been developed to cope with labor pain and improve the delivery experience and satisfaction of pregnant women. The results of different types of medical intervention on women's expectant pain have been varied. Therefore, this systematic review was aimed at summarizing the body of evidence regarding the effects of various non-pharmacological coping strategies for reducing labor pain.

METHODS

The review was conducted according to guidelines of the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA). We systematically searched the articles published between 1989 and 2020 in six electronic databases: PubMed, MEDLINE, CINAHL, WOS, PsycARTICLES, and Airiti Library, and the reference lists of the Clinical Trial Registry. Twenty studies were identified, with eight eligible studies included in the Bayesian network meta-analysis.

RESULTS

Eight studies with 713 participants were included in the meta-analysis with nine different non-pharmacological strategies for reducing labor pain. The traditional meta-analysis demonstrated that the non-pharmacological coping strategies were effective in reducing labor pain. Of these interventional strategies, the ranking probabilities analysis of the network meta-analysis suggested that the Bonapace Method may be the most effective strategy in reducing labor pain, followed by acupressure.

CONCLUSIONS

Non-pharmacological coping strategies can reduce labor pain while maintaining an effective and satisfactory delivery experience. This systematic review, by synthesizing the body of evidence, demonstrated that non-pharmacological coping strategies are effective in reducing labor pain. Furthermore, as demonstrated in the network meta-analysis, the Bonapace Method, modulating birth pain by involving the father, is the most effective non-pharmacological intervention for reducing labor pain.