Association between interpregnancy interval and the labor curve.

BACKGROUND: Both short and long interpregnancy intervals are associated with adverse pregnancy outcomes; however, the impact of interpregnancy intervals on labor progression is unknown. OBJECTIVE: We examined the impact of interpregnancy intervals on the labor curve, hypothesizing that those with a longer interpregnancy intervals would have slower labor progression. STUDY DESIGN: This is a retrospective cohort study of patients with a history of one prior vaginal delivery admitted for induction of labor or spontaneous labor with a singleton gestation ≥37 weeks at an academic medical center between 2004 and 2015. Repeated measures regression was used to construct labor curves, which were compared between patients with short interpregnancy intervals, defined as <3 years since the last delivery, and long interpregnancy intervals, defined as >3 years since the last delivery. We chose this interval as it approximates the median birth interval in the United States. Interval-censored regression was used to estimate the median duration of labor after 4 centimeters of dilation, stratified by type of labor (spontaneous vs induced). Multivariate analysis was used to adjust for potential confounders. RESULTS: Of the 1331 patients who were included in the analysis, 544 (41%) had a long interpregnancy interval. Among the entire cohort, there were no significant differences in first or second-stage progression between short and long interpregnancy interval groups. In the stratified analysis, first-stage progression varied between groups on the basis of labor type: long interpregnancy interval was associated with a slower active phase among those being induced and a quicker active phase among those in spontaneous labor. The second-stage duration was similar between cohorts regardless of labor type. CONCLUSION: Multiparas with an interpregnancy interval >3 years may have a slower active phase than those with a shorter interpregnancy interval when undergoing induction of labor. Interpregnancy interval does not demonstrate an effect on the length of the second stage.

Prediction of spontaneous vaginal delivery in the prolonged second stage using the delta angle of progression.

BACKGROUND: It is clinically challenging to determine when to intervene in the prolonged second stage. Although individualized prediction of spontaneous vaginal delivery is crucial to avoid maternal and neonatal complications associated with operative deliveries, the approach has not been fully established. OBJECTIVE: We aimed to evaluate the predictability of spontaneous vaginal delivery using the difference in angle of progression between pushing and rest, delta angle of progression, to establish a novel method to predict spontaneous vaginal delivery during the prolonged second stage in nulliparous women with epidural anesthesia. STUDY DESIGN: We retrospectively analyzed deliveries of nulliparous women with epidural anesthesia between September 2018 and October 2023. Women were included if their delta angle of progression during the second stage was available. Operative deliveries were defined as the cases that required forceps, vacuum, and cesarean deliveries due to labor arrest. Women requiring operative deliveries due to fetal and maternal concerns, or women with fetal occiput posterior presentation were excluded. The second stage was stratified into the prolonged second stage, the period after 3 hours in the second stage, and the normal second stage, the period from the beginning until the third hour of the second stage. The association of the delta angle of the progression measured during each stage with spontaneous vaginal delivery and operative deliveries was investigated. Furthermore, the predictability of spontaneous vaginal delivery was evaluated by combining the delta and rest angle of progression. RESULTS: A total of 129 women were eligible for analysis. The delta angle of progression measured during the prolonged second stage and normal second stage were significantly larger in women who achieved spontaneous vaginal delivery compared to operative deliveries (p<.001 and p<.05, respectively). During the prolonged second stage, a cutoff of 18.8 derived from the receiver operative characteristic curves in the context of the delta angle of progression predicted the possibility of spontaneous vaginal delivery (sensitivity, 81.8%; specificity, 60.0%; AUC, 0.76). Combining the rest angle of progression (>140) and delta angle of progression (>18.8) also provided quantitative prediction of spontaneous vaginal delivery (sensitivity, 86.7%; specificity, 70.0%; AUC, 0.80). CONCLUSION: The delta angle of progression alone or in combination with the rest angle of progression can be used to predict spontaneous vaginal delivery in the second stage in nulliparous women with epidural anesthesia. Quantitative analysis of the effect of pushing using the delta angle of progression provides an objective guide to assist with an assessment of labor dystocia in the prolonged second stage on an individualized basis, which may optimize labor management in the prolonged second stage by reducing neonatal and maternal complications related to unnecessary operative deliveries and prolonged second stage of labor.

Effects of perineal massage at different stages on perineal and postpartum pelvic floor function in primiparous women: a systematic review and meta-analysis.

BACKGROUND: Perineal massage, as a preventive intervention, has been shown to reduce the risk of perineal injuries and may have a positive impact on pelvic floor function in the early postpartum period. However, there is still debate concerning the best period to apply perineal massage, which is either antenatal or in the second stage of labor, as well as its safety and effectiveness. Meta-analysis was used to evaluate the effect of implementing perineal massage in antenatal versus the second stage of labor on the prevention of perineal injuries during labor and early postpartum pelvic floor function in primiparous women. METHODS: We searched nine different electronic databases from inception to April 16, 2024. The randomized controlled trials (RCTs) we included assessed the effects of antenatal and second-stage labor perineal massage in primiparous women. All data were analyzed with Revman 5.3, Stata Statistical Software, and Risk of Bias 2 was used to assess the risk of bias. Subgroup analyses were performed based on the different periods of perineal massage. The primary outcomes were the incidence of perineal integrity and perineal injury. Secondary outcomes were perineal pain, duration of the second stage of labor, postpartum hemorrhage, urinary incontinence, fecal incontinence, and flatus incontinence. RESULTS: This review comprised a total of 10 studies that covered 1057 primigravid women. The results of the analysis showed that perineal massage during the second stage of labor reduced the perineal pain of primigravid women in the immediate postpartum period compared to the antenatal period, with a statistical value of (MD = -2.29, 95% CI [-2.53, -2.05], P < 0.001). Additionally, only the antenatal stage reported that perineal massage reduced fecal incontinence (P = 0.04) and flatus incontinence (P = 0.01) in primiparous women at three months postpartum, but had no significant effect on urinary incontinence in primiparous women at three months postpartum (P = 0.80). CONCLUSIONS: Reducing perineal injuries in primiparous women can be achieved by providing perineal massage both antenatally and during the second stage of labor. Pelvic floor function is improved in the postnatal phase by perineal massage during the antenatal stage. TRIAL REGISTRATION: CRD42023415996 (PROSPERO).

Effects of Fetal Position on the Loading of the Fetal Brain During the Onset of the Second Stage of Labor.

During vaginal delivery, the delivery requires the fetal head to mold to accommodate the geometric constraints of the birth canal. Excessive molding can produce brain injuries and long-term sequelae. Understanding the loading of the fetal brain during the second stage of labor (fully dilated cervix, active pushing, and expulsion of fetus) could thus help predict the safety of the newborn during vaginal delivery. To this end, this study proposes a finite element model of the fetal head and maternal canal environment that is capable of predicting the stresses experienced by the fetal brain at the onset of the second phase of labor. Both fetal and maternal models were adapted from existing studies to represent the geometry of full-term pregnancy. Two fetal positions were compared: left-occiput-anterior and left-occiput-posterior. The results demonstrate that left-occiput-anterior position reduces the maternal tissue deformation, at the cost of higher stress in the fetal brain. In both cases, stress is concentrated underneath the sutures, though the location varies depending on the presentation. In summary, this study provides a patient-specific simulation platform for the study of vaginal delivery and its effect on both the fetal brain and maternal anatomy. Finally, it is suggested that such an approach has the potential to be used by obstetricians to support their decision-making processes through the simulation of various delivery scenarios.

On the uncertainty quantification of the active uterine contraction during the second stage of labor simulation.

Uterine contractions in the myometrium occur at multiple scales, spanning both organ and cellular levels. This complex biological process plays an essential role in the fetus delivery during the second stage of labor. Several finite element models of active uterine contractions have already been developed to simulate the descent of the fetus through the birth canal. However, the developed models suffer severe reliability issues due to the uncertain parameters. In this context, the present study aimed to perform the uncertainty quantification (UQ) of the active uterine contraction simulation to advance our understanding of pregnancy mechanisms with more reliable indicators. A uterus model with and without fetus was developed integrating a transversely isotropic Mooney-Rivlin material with two distinct fiber orientation architectures. Different contraction patterns with complex boundary conditions were designed and applied. A global sensitivity study was performed to select the most valuable parameters for the uncertainty quantification (UQ) process using a copula-based Monte Carlo method. As results, four critical material parameters ( C 1 , C 2 , K , Ca 0 ) of the active uterine contraction model were identified and used for the UQ process. The stress distribution on the uterus during the fetus descent, considering first and second fiber orientation families, ranged from 0.144 to 1.234 MPa and 0.044 to 1.619 MPa, respectively. The simulation outcomes revealed also the segment-specific contraction pattern of the uterus tissue. The present study quantified, for the first time, the effect of uncertain parameters of the complex constitutive model of the active uterine contraction on the fetus descent process. As perspectives, a full maternal pelvis model will be coupled with reinforcement learning to automatically identify the delivery mechanism behind the cardinal movements of the fetus during the active expulsion process.

Mechanics of vaginal breech birth: Factors influencing obstetric maneuver rate, duration of active second stage of labor, and neonatal outcome.

BACKGROUND: We investigated possible parameters that could predict the need for obstetric maneuvers, the duration of the active second stage of labor (i.e., the duration of active pushing), and short-term neonatal outcome in vaginal breech births. MATERIALS AND METHODS: We performed a retrospective analysis of 268 successful singleton vaginal breech births in women without previous vaginal births from January 2015 to August 2022. Multivariable regression was used to investigate associations between maternal and fetal characteristics (including antepartum magnetic resonance (MR) pelvimetry) with obstetric maneuvers, the duration of active second stage of labor, pH values, and admission to the neonatal unit. Models for the prediction of obstetric maneuvers were built and internally validated. RESULTS: Obstetric maneuvers were performed in a total of 130 women (48.5%). A total of 32 neonates (11.9%) had to be admitted to the neonatal unit. The intertuberous distance (ITD) (p < 0.001), epidural analgesia (p < 0.001), and birthweight (p = 0.026) were associated with the duration of active second stage of labor. ITD (p = 0.028) and birthweight (p = 0.011) were also independently associated with admission to the neonatal unit, while pH values below 7.10 dropped significantly (p = 0.0034) if ITD was ≥13 cm. Furthermore, ITD (p < 0.001) and biparietal diameter (p = 0.002) were independent predictors for obstetric maneuvers. CONCLUSIONS: ITD is independently associated with the duration of active second stage of labor. Thus, it can predict suboptimal birth mechanics in the last stage of birth, which may lead to the need for obstetric maneuvers, lower arterial pH values, and admission to the neonatal unit. Consequently, MR pelvimetry gives additional information for practitioners and birthing people preferring a vaginal breech birth.

Moderate or intensive management of the active phase of second-stage labor and risk of urinary and anal incontinence: results of the PASST randomized controlled trial.

BACKGROUND: Incontinence occurs frequently in the postpartum period. Several theoretical pathophysiological models may underlie the hypothesis that different types of management of the active phase of the second stage of labor have different effects on pelvic floor muscles and thus perhaps affect urinary and anal continence. OBJECTIVE: This study aimed to evaluate the impact of "moderate pushing" on the occurrence of urinary or anal incontinence compared with "intensive pushing," and to determine the factors associated with incontinence at 6 months postpartum. STUDY DESIGN: This was a planned analysis of secondary objectives of the PASST (Phase Active du Second STade) trial, a multicenter randomized controlled trial. PASST included nulliparous women with singleton term pregnancies and epidural analgesia, who were randomly assigned at 8 cm of dilatation to either the intervention group that used "moderate" pushing (pushing only twice during each contraction, resting regularly for 1 contraction in 5 without pushing, and no time limit on pushing) or the control group following the usual management of "intensive" pushing (pushing 3 times during each contraction, with no contractions without pushing, with an obstetrician called to discuss operative delivery after 30 minutes of pushing). Data about continence were collected with validated self-assessment questionnaires at 6 months postpartum. Urinary incontinence was defined by an ICIQ-UI SF (International Consultation on Incontinence Questionnaire-Urinary Incontinence Short Form) score ≥1 and anal incontinence by a Wexner score ≥2. A separate analysis was also performed among the more severely affected women (ICIQ-UI SF ≥6 and Wexner ≥5). Factors associated with incontinence were assessed with univariate and multivariable analyses. RESULTS: Among 1618 women initially randomized, 890 (55%) returned the complete questionnaire at 6 months. The rate of urinary incontinence was 36.6% in the "moderate" pushing group vs 38.5% in the "intensive" pushing group (relative risk, 0.95; 95% confidence interval, 0.80-1.13), whereas the rate of anal incontinence was 32.2% vs 34.6% (relative risk, 0.93; 95% confidence interval, 0.77-1.12). None of the obstetrical factors studied related to the second stage of labor influenced the occurrence of urinary or anal incontinence, except operative vaginal delivery, which increased the risk of anal incontinence (adjusted odds ratio, 1.50; 95% confidence interval, 1.04-2.15). CONCLUSION: The results of the PASST trial indicate that neither moderate nor intensive pushing efforts affect the risk of urinary or anal incontinence at 6 months postpartum among women who gave birth under epidural analgesia.

Alternative to intensive management of the active phase of the second stage of labor: a multicenter randomized trial (Phase Active du Second STade trial) among nulliparous women with an epidural.

BACKGROUND: There is no consensus on an optimal strategy for managing the active phase of the second stage of labor. Intensive pushing could not only reduce pushing duration, but also increase abnormal fetal heart rate because of cord compression and reduced placental perfusion and oxygenation resulting from the combination of uterine contractions and maternal expulsive forces. Therefore, it may increase the risk of neonatal acidosis and the need for operative vaginal delivery. OBJECTIVE: This study aimed to assess the effect of the management encouraging "moderate" pushing vs "intensive" pushing on neonatal morbidity. STUDY DESIGN: This study was a multicenter randomized controlled trial, including nulliparas in the second stage of labor with an epidural and a singleton cephalic fetus at term and with a normal fetal heart rate. Of note, 2 groups were defined: (1) the moderate pushing group, in which women had no time limit on pushing, pushed only twice during each contraction, and observed regular periods without pushing, and (2) the intensive pushing group, in which women pushed 3 times during each contraction and the midwife called an obstetrician after 30 minutes of pushing to discuss operative delivery (standard care). The primary outcome was a composite neonatal morbidity criterion, including umbilical arterial pH of <7.15, base excess of >10 mmol/L, lactate levels of >6 mmol/L, 5-minute Apgar score of <7, and severe neonatal trauma. The secondary outcomes were mode of delivery, episiotomy, obstetrical anal sphincter injuries, postpartum hemorrhage, and maternal satisfaction. RESULTS: The study included 1710 nulliparous women. The neonatal morbidity rate was 18.9% in the moderate pushing group and 20.6% in the intensive pushing group (P=.38). Pushing duration was longer in the moderate group than in the intensive group (38.8±26.4 vs 28.6±17.0 minutes; P<.001), and its rate of operative delivery was 21.1% in the moderate group compared with 24.8% in the intensive group (P=.08). The episiotomy rate was significantly lower in the moderate pushing group than in the intensive pushing group (13.5% vs 17.8%; P=.02). We found no significant difference for obstetrical anal sphincter injuries, postpartum hemorrhage, or maternal satisfaction. CONCLUSION: Moderate pushing has no effect on neonatal morbidity, but it may nonetheless have benefits, as it was associated with a lower episiotomy rate.

The effect of two midwives during the second stage of labour to reduce severe perineal trauma (Oneplus): a multicentre, randomised controlled trial in Sweden.

BACKGROUND: Severe perineal trauma (SPT) affecting the anal sphincter muscle complex is a serious complication following childbirth, associated with short-term and long-term maternal morbidity. Effective preventive strategies are still scarce. The aim of the Oneplus trial was to test the hypothesis that the presence of a second midwife during the second stage of labour, with the purpose of preventing SPT, would result in fewer injuries affecting the anal sphincter than if attended by one midwife. METHODS: In this multicentre, randomised, controlled parallel group, unmasked trial done at five obstetric units in Sweden, women were randomly assigned to be assisted by either one or two midwives in late second stage. Nulliparous women and women planning the first vaginal birth after caesarean section who were age 18-47 years were randomly assigned to an intervention when reaching the second stage of labour. Further inclusion criteria were gestational week 37+0, carrying a singleton live fetus in vertex presentation, and proficiency in either Swedish, English, Arabic, or Farsi. Exclusion criteria were a multiple pregnancy, intrauterine fetal demise, a planned caesarean section, or women who were less than 37 weeks pregnant. Randomisation to the intervention group of two midwives or standard care group of one midwife (1:1) was done using a computer-based program and treatment groups were allocated by use of sealed opaque envelopes. All women and midwives were aware of the group assignment, but the statistician from Clinical Studies Forum South, who did the analyses, was masked to group assignment. Midwives were instructed to implement existing prevention models and the second midwife was to assist on instruction of the primary midwife, when asked. Midwives were also instructed to complete case report forms detailing assistance techniques and perineal trauma prevention techniques. The primary outcome was the proportion of women who had SPT, for which odds ratios (ORs) and 95% CIs were calculated, and logistic regression was done to adjust for study site. All analyses were done according to intention to treat. The trial is registered with ClinicalTrials.gov, NCT0377096. FINDINGS: Between Dec 10, 2018, and March 21, 2020, 8866 women were assessed for eligibility, and 4264 met the inclusion criteria and agreed to participate. 3776 (88·5%) of 4264 women were randomly assigned to an intervention after reaching the second stage of labour. 1892 women were assigned to collegial assistance (two midwives) during the second stage of labour and 1884 women were assigned to standard care (one midwife). 13 women in each group did not meet the inclusion criteria and were excluded. After further exclusions, 1546 women spontaneously gave birth in the intervention group and 1513 in the standard care group. 1546 women in the intervention group and 1513 in the standard care group were included in the intention-to-treat analysis of the primary outcome. There was a significant reduction in SPT in the intervention group (3·9% [61 of 1546] vs 5·7% [86 of 1513]; adjusted OR 0·69 (0·49-0·97). INTERPRETATION: The presence of two midwives during the active second stage can reduce SPT in women giving birth for the first time. FUNDING: The Swedish Research Council for Health, Working Life and Welfare; Jan Hains Research Foundation; and Skane County Council's Research and Development Foundation.

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.

Combined perineal massage and warm compress compared to massage alone during active second stage of labour in nulliparas: A randomised trial.

OBJECTIVE: To evaluate the effect of combined perineal massage and warm compress to the perineum (MassComp) compared to perineal massage alone during pushing in the second stage of labour in reducing perineal trauma requiring suturing in nulliparas. STUDY DESIGN: A randomised trial was performed in a University hospital, Malaysia from June 2020 to May 2021. 281 term nulliparas who were about to start pushing in the second stage of labour were randomised to combined perineal massage and warm compress or perineal massage alone to the perineum. Primary outcome was suturing for perineal injury (episiotomy or tear). The Chi-square test was used to analyse categorical data, Student t test to compare means and distributions for normally distributed continuous data and Mann Whitney U test for appropriate ordinal data. RESULTS: Data from 277 participants (140 MassComp arm, 137 perineal massage alone arm) were analysed based on modified intention to treat basis. Perineal suturing rates were 133/140(95.0%) [MassComp] vs. 128/137(93.4%) [perineal massage alone] RR 1.02(95%CI 0.96-1.08), P = 0.615. Of the secondary outcomes, Likert scale response to recommend allocated treatment to a friend was 103/140(73.6%) vs. 84/137(61.3%) RR 1.20(95%CI 1.02-1.42)NNTb 9(95%CI 4.3-76.4) P = 0.029, participants' satisfaction with care (visual numerical rating scale 0-10) median [interquartile range] 6[6-8] vs. 6[5-8] P = 0.392, intervention to delivery intervals were 25[15-35] vs. 19[14-30] minutes P = 0.012, major perineal injury (episiotomy, second degree or higher tears) rates 116/140(82.9%) vs. 119/137(86.9%) RR 0.95(95%CI 0.86-1.05), P = 0.404, episiotomy rates 97/140(69.3%) vs. 97/140(70.8%) RR 0.98(95%CI 0.84-1.14), P = 0.795, and spontaneous vaginal delivery rates 103/140(73.6%) vs. 106/137(77.4%) RR 0.95(95%CI 0.83-1.09), P = 0.488 for MassComp vs. perineal massage alone respectively. Other maternal and neonatal outcomes were not significantly different. CONCLUSION: Massage and warm compress during pushing did not decrease the likelihood of perineal injury requiring suturing in nulliparas when compared to perineal massage alone. Women were more likely to recommend massage and warm compress during pushing to a friend.

Delayed versus early pushing during the second stage of labour in primigravidas under epidural anaesthesia with occipitoposterior malposition: a randomised controlled study.

This randomised controlled trial aimed to compare the effect of early and delayed pushing during the second stage of labour in women with occipitoposterior (OP) malposition. It included 184 nulliparous women with OP position randomised to early pushing in which women were allowed to push within one hour after full cervical dilatation or delayed pushing in which women were asked not to push for maximum of three hours or start pushing when the vertex was visible. The primary outcome was successful vaginal delivery. The rate of spontaneous vaginal delivery was significantly higher in the early pushing group (80.4 vs. 60.9%, p=.004) while the rate of instrumental vaginal delivery (30.4 vs. 15.4%) and CS (8.7 vs. 4.3%) was significantly higher in the delayed pushing group. Women in the delayed pushing group showed a significantly longer duration of the second stage (129.4 ± 7.5 vs. 61.6 ± 15.3 minutes, p<.001) and shorter duration of pushing (219.8 ± 74.8 vs. 693.9 ± 145.2 seconds, p<.001) .The rate of 2nd and 3rd degree perineal lacerations (19.6 and 13% vs. 5.4 and 8.7% respectively, p=.013) and vaginal tears (41.3 vs. 8.7%, p<.001) was significantly higher in the early pushing group. We concluded that early pushing during the second stage of labour is associated with higher rates of spontaneous vaginal delivery and vaginal and perineal lacerations.Clinical trial registration NCT03121274.Impact StatementWhat is already known on this subject? Occipitoposterior malposition is common during delivery especially in primigravida and is associated with higher rates of instrumental delivery and caesarean section. It can be managed through early or delayed pushing.What the results of this study add? Early pushing is associated with higher rates of spontaneous vaginal delivery, perineal and vaginal tears, shorter duration of second stage of labour, shorter duration of pushing, lower rates of both instrumental vaginal delivery and caesarean section.What the implications are of these findings for clinical practice and/or further research? Early pushing during the second stage of labour is associated with higher rates of spontaneous vaginal delivery and vaginal and perineal lacerations in women with OP malposition and should be tried and not delaying the pushing.

DNA damage analysis in newborns and their mothers related to pregnancy and delivery characteristics.

INTRODUCTION: Increased DNA damage is associated with early events in carcinogenesis. The foetus may be more susceptible to effects of environment by transplacental exposure. We aimed to evaluate DNA damage in cells from umbilical cord (arteries and vein) and maternal blood from pregnant women. METHODS: Fifty eight pregnant women and their offspring were included in this study. They were submitted to an interview to obtain information about personal history, clinical history, and lifestyle habits. Other Information was obtained from medical records. The samples were prepared for Single Cell Gel/Comet assay and Cytokinesis-block Micronucleus Cytome (CBMN-Cyt) assay. RESULTS: Correlation between DNA damage frequency by Comet assay from newborns and their mothers was statistically significant and was significantly associated with nulliparity and more than 1 h of second stage of labour (umbilical vein and maternal blood). A positive MNi relationship was noticed for age (mother's blood) and inappropriate birth weight for gestational age (maternal blood). When multivariate statistical analyses were applied to measure the degree of association between variables that influenced DNA damage markers in the first evaluation, inadequate birth weight and pregnant weight gain were associated with MNi frequency in maternal and newborns blood, respectively. DISCUSSION: Significant associations between DNA damage in newborns and pregnant women, and birth and pregnancy events suggest molecular evidence of transplacental genotoxic effects. However, a potentially increased risk of degenerative diseases, such as cancers, in this population should be carefully investigated by further prospective cohort studies.

The prevalence of uterine fundal pressure during the second stage of labour for women giving birth in health facilities: a systematic review and meta-analysis.

BACKGROUND: Uterine fundal pressure involves a birth attendant pushing on the woman's uterine fundus to assist vaginal birth. It is used in some clinical settings, though guidelines recommend against it. This systematic review aimed to determine the prevalence of uterine fundal pressure during the second stage of labour for women giving birth vaginally at health facilities. METHODS: The population of interest were women who experienced labour in a health facility and in whom vaginal birth was anticipated. The primary outcome was the use of fundal pressure during second stage of labour. MEDLINE, EMBASE, CINAHL and Global Index Medicus databases were searched for eligible studies published from 1 January 2000 onwards. Meta-analysis was conducted to determine a pooled prevalence, with subgroup analyses to explore heterogeneity. RESULTS: Eighty data sets from 76 studies (n = 898,544 women) were included, reporting data from 22 countries. The prevalence of fundal pressure ranged from 0.6% to 69.2% between studies, with a pooled prevalence of 23.2% (95% CI 19.4-27.0, I2 = 99.97%). There were significant differences in prevalence between country income level (p < 0.001, prevalence highest in lower-middle income countries) and method of measuring use of fundal pressure (p = 0.001, prevalence highest in studies that measured fundal pressure based on women's self-report). CONCLUSIONS: The use of uterine fundal pressure on women during vaginal birth in health facilities is widespread. Efforts to prevent this potentially unnecessary and harmful practice are needed.

Uterine fundal pressure involves a health worker pushing on the uppermost part of a woman's abdomen during the pushing phase of labour, with the aim of assisting or accelerating vaginal birth. The World Health Organization and other bodies specifically recommend against the use of fundal pressure, as it is not beneficial and is potentially harmful to women. This study undertook a review to determine how often fundal pressure is used on women giving birth in hospitals around the world. We searched five databases and found 76 studies from 22 countries. We determined that 23.2% of women experience some form of fundal pressure during the pushing phase of labour. Results between studies varied widely, ranging from 0.6% to 69.2% of women experiencing some form of fundal pressure. This may be due to different study populations, or different methods of assessing or documenting fundal pressure use. It may also reflect differences in clinical practice or guidelines. Despite these differences, our findings indicate uterine fundal pressure is still widespread and efforts to prevent this potentially unnecessary and harmful practice are needed.

Second stage expedite delivery of low birth weight neonates: Emergent cesarean delivery versus vacuum assisted delivery.

OBJECTIVE: To determine maternal and neonatal outcomes among women undergoing second stage emergent cesarean delivery (ECD) versus vacuum-assisted delivery (VAD) of low birthweight neonates. MATERIALS AND METHODS: A retrospective cohort study from two tertiary medical centers. We included women who underwent either ECD or VAD during the second stage of labor, and delivered neonates with a birthweight of <2500 g during 2011-2019. Characteristics and outcomes were compared between the groups. The primary outcome was the rate of a composite adverse neonatal outcome, defined as the presence of ≥1 of the following: Apgar 5 min < 7, respiratory distress syndrome, neonatal intensive care unit admission, mechanical ventilation and intrapartum fetal death. RESULTS: The study cohort included 611 patients, of whom 46 had ECD and 565 had VAD. Baseline characteristics did not differ between the groups. The rate of Apgar score < 7 at 1 min was higher among the ECD group]10 (22%) vs. 29 (5%), OR (95% CI) 5.1 (2.3-11.3), p < 0.001[. Other neonatal and maternal outcomes were similar in both groups. CONCLUSIONS: Neonatal and maternal outcomes do not differ substantially between ECD and VAD of neonates weighing <2500 g. This information may be useful when contemplating the preferred mode of delivery in this setting.

The role of the angle of progression in the prediction of the outcome of occiput posterior position in the second stage of labor.

BACKGROUND: Occiput posterior position is the most frequent cephalic malposition, and its persistence at delivery is associated with a higher risk of maternal and perinatal morbidity. Diagnosis and management of occiput posterior position remain a clinical challenge. This is partly caused by our inability to predict fetuses who will spontaneously rotate into occiput anterior from those who will have persistent occiput posterior position. The angle of progression, measured with transperineal ultrasound, represents a reliable tool for the evaluation of fetal head station during labor. The relationship between the persistence of occiput posterior position and fetal head station in the second stage of labor has not been previously assessed. OBJECTIVE: This study aimed to evaluate the role of fetal head station, as measured by the angle of progression, in the prediction of persistent occiput posterior position and the mode of delivery in the second stage of labor. STUDY DESIGN: We recruited a nonconsecutive series of women with posterior occiput position diagnosed by transabdominal ultrasound in the second stage of labor. For each woman, a transperineal ultrasound was performed to measure the angle of progression at rest. We compared the angle of progression between women who delivered fetuses in occiput anterior position and those with persistent occiput posterior position at delivery. Receiver operating characteristics curves were performed to evaluate the accuracy of the angle of progression in the prediction of persistent occiput posterior position. Finally, we performed a multivariate logistic regression to determine independent predictors of persistent occiput posterior position. RESULTS: Overall, 63 women were included in the analysis. Among these, 39 women (62%) delivered in occiput anterior position, whereas 24 (38%) delivered in occiput posterior position (persistent occiput posterior position). The angle of progression was significantly narrower in the persistent occiput posterior position group than in women who delivered fetuses in occiput anterior position (118.3°±12.2° vs 127.5°±10.5°; P=.003). The area under the receiver operating characteristics curve was 0.731 (95% confidence interval, 0.594-0.869) with an estimated best cutoff range of 121.5° (sensitivity of 72% and specificity of 67%). On logistic regression analysis, the angle of progression was found to be independently associated with persistence of occiput posterior position (odds ratio, 0.942; 95% confidence interval, 0.889-0.998; P=.04). Finally, women who underwent cesarean delivery had significantly narrower angle of progression than women who had a vaginal delivery (113.5°±8.1 vs 128.0°±10.7; P<.001). The area under the receiver operating characteristics curve for the prediction of cesarean delivery was 0.866 (95% confidence interval, 0.761-0.972). At multivariable logistic regression analysis including the angle of progression, parity, and gestational age at delivery, the angle of progression was found to be the only independent predictor associated with cesarean delivery (odds ratio, 0.849; 95% confidence interval, 0.775-0.0930; P<.001). CONCLUSION: In fetuses with occiput posterior at the beginning of the second stage of labor, narrower values of the angle of progression are associated with higher rates of persistent occiput posterior position at delivery and a higher risk of cesarean delivery.

Labor Dystocia in Nulliparous Women.

Dystocia (abnormally slow or protracted labor) accounts for 25% to 55% of primary cesarean deliveries. The latent phase of labor begins with onset of regular, painful contractions and continues until 6 cm of cervical dilation. Current recommendations are to avoid admission to labor and delivery during the latent phase, assuming maternal/fetal status is reassuring. The active phase begins at 6 cm. An arrested active phase is defined as more than four hours without cervical change despite rupture of membranes and adequate contractions and more than six hours of no cervical change without adequate contractions. Managing a protracted active phase includes oxytocin augmentation with or without amniotomy. The second stage of labor begins at complete cervical dilation and continues to delivery. This stage is considered protracted if it lasts three hours or more in nulliparous patients without an epidural or four hours or more in nulliparous patients with an epidural. Primary interventions for a protracted second stage include use of oxytocin and manual rotation if the fetus is in the occiput posterior position. When contractions or pushing is inadequate, vacuum or forceps delivery may be needed. Effective measures for preventing dystocia and subsequent cesarean delivery include avoiding admission during latent labor, providing cervical ripening agents for induction in patients with an unfavorable cervix, encouraging the use of continuous labor support (e.g., a doula), walking or upright positioning in the first stage, and not diagnosing failed induction during the latent phase until oxytocin has been given for 12 to 18 hours after membrane rupture. Elective induction at 39 weeks' gestation in low-risk nulliparous patients may reduce the risk of cesarean delivery.

Elite Athletes and Pregnancy Outcomes: A Systematic Review and Meta-analysis.

PURPOSE: The purpose of this systematic review was to evaluate fetal and maternal pregnancy outcomes of elite athletes who had participated in competitive sport immediately before conception. METHODS: Online databases were searched up to March 24, 2020. Studies of any design and language were eligible if they contained information on the relevant population (pregnant women), exposure (engaged in elite sport immediately before pregnancy), and outcomes (birth weight, low birth weight, macrosomia, preterm birth, fetal heart rate and pulse index, cesarean sections, instrumental deliveries, episiotomies, duration of labor, perineal tears, pregnancy-induced low back pain, pelvic girdle pain, urinary incontinence, miscarriages, prenatal weight gain, inadequate/excess prenatal weight gain, maternal depression or anxiety). RESULTS: Eleven unique studies (n = 2256 women) were included. We identified "low" certainty evidence demonstrating lower rates of low back pain in elite athletes compared with active/sedentary controls (n = 248; odds ratio, 0.38; 95% confidence interval, 0.20-0.73; I2 = 0%) and "very low" certainty evidence indicating an increased odds of excessive prenatal weight gain in elite athletes versus active/sedentary controls (n = 1763; odds ratio, 2.47; 95% confidence interval, 1.26-4.85; I2 = 0%). Low certainty evidence from two studies (n = 7) indicated three episodes of fetal bradycardia after high-intensity exercise that resolved within 10 min of cessation of activity. No studies reported inadequate gestational weight gain or maternal depression or anxiety. There were no differences between elite athletes and controls for all other outcomes. CONCLUSIONS: There is "low" certainty of evidence that elite athletes have reduced odds of experiencing pregnancy-related low back pain and "very low"certainty of evidence that elite athletes have increased the odds of excessive weight gain compared with active/sedentary controls. More research is needed to provide strong evidence of how elite competitive sport before pregnancy affects maternal and fetal outcomes.PROSPERO Registration: CRD42020167382.

Comparison of maternal and fetal outcomes between delayed and immediate pushing in the second stage of vaginal delivery: systematic review and meta-analysis of randomized controlled trials.

BACKGROUND: The second stage of labor begins with complete dilatation of the cervix until delivery of the fetus. After the cervix has fully dilated, the caregiver/nurse will provide guidance to the mother regarding the push technique for delivering the fetus (immediate pushing, IP). Because some women receive analgesic medications during labor, they might not be able to push correctly. Therefore, some obstetricians choose to postpone guiding the patient to push until the cervix is fully dilated and the fetal head has begun to descend. At this point, there is an involuntary exertion sensation (delayed pushing, DP) that saves energy and, at the same time, decreases tiredness and fatigue. The best timing for pushing during the second stage of labor is still controversial. The aim of this study was to investigate the different maternal and neonatal outcomes with IP and DP in the second stage of labor. METHODS: The Cochrane Library, EMBASE, PubMed, and Airiti Library (a Chinese database) were searched up to July 2019. Search keywords included: "labor stage, second", "delayed pushing", and "immediate pushing". Gray literature and bibliographies of articles were checked. No language restrictions were applied. Only randomized controlled trials were included. Two independent reviewers identified relevant studies and extracted data. The quality of the studies was assessed using the Cochrane's Risk of Bias tool. A random-effects meta-analysis was used to pool results. Mean differences and risk ratios were calculated with 95% confidence intervals (CIs) using Review Manager 5.3 (The Nordic Cochrane Centre, Copenhagen, Denmark, 2014). The risk of heterogeneity was reported as I2, and publication bias was visually assessed by funnel plots. RESULTS: In total, 15 studies (n = 6121 participants) were identified. Pooled results demonstrated the following. (1) As to maternal outcomes, in comparison, IP shortened the length of the second stage of labor by 40.9 (95% CI 23.6-58.2) min; however, DP decreased the total length of pushing by 25.4 (95% CI 13.9-37.0) min. The incidence of instrument-assisted vaginal delivery was significantly lower in the DP group in western countries (RR 0.85, 95% CI 0.74-0.97). In addition, the maternal postpartum fatigue score was 0.67 points lower in the DP group (95% CI - 1.09 to - 0.26). There was no statistical significance of the cesarean section rate or blood loss. (2) As to neonatal outcomes (Apgar score at 1 min), the DP group showed a higher score (by 0.19; 95% CI 0.10-0.27 points) than the IP group. CONCLUSIONS: Delayed pushing can decrease the total pushing time and decrease the fatigue score after delivery without significant adverse events compared to the early pushing group. Therefore, we recommend that caregivers instruct the pushing time at the optimal moment, which allows women to have more resting time and save energy during labor.

Obesity, Second Stage Duration, and Labor Outcomes in Nulliparous Women.

OBJECTIVE: This study aimed to estimate second stage duration and its effects on labor outcomes in obese versus nonobese nulliparous women. STUDY DESIGN: This was a secondary analysis of a cohort of nulliparous women who presented for labor at term and reached complete cervical dilation. Adjusted relative risks (aRR) were used to estimate the association between obesity and second stage characteristics, composite neonatal morbidity, and composite maternal morbidity. Effect modification of prolonged second stage on the association between obesity and morbidity was assessed by including an interaction term in the regression model. RESULTS: Compared with nonobese, obese women were more likely to have a prolonged second stage (aRR: 1.48, 95% CI: 1.18-1.85 for ≥3 hours; aRR: 1.65, 95% CI: 1.18-2.30 for ≥4 hours). Obesity was associated with a higher rate of second stage cesarean (aRR: 1.78, 95% CI: 1.34-2.34) and cesarean delivery for fetal distress (aRR: 2.67, 95% CI: 1.18-3.58). Obesity was also associated with increased rates of neonatal (aRR: 1.38, 95% CI: 1.05-1.80), but not maternal morbidity (aRR: 1.06, 95% CI: 0.90-1.25). Neonatal morbidity risk was not modified by prolonged second stage. CONCLUSION: Obesity is associated with increased risk of neonatal morbidity, which is not modified by prolonged second stage of labor.