The second stage of labor.

The second stage of labor extends from complete cervical dilatation to delivery. During this stage, descent and rotation of the presenting part occur as the fetus passively negotiates its passage through the birth canal. Generally, descent begins during the deceleration phase of dilatation as the cervix is drawn upward around the fetal presenting part. The most common means of assessing the normality of the second stage of labor is to measure its duration, but progress can be more meaningfully gauged by measuring the change in fetal station as a function of time. Accurate clinical identification and evaluation of differences in patterns of fetal descent are necessary to assess second stage of labor progress and to make reasoned judgments about the need for intervention. Three distinct graphic abnormalities of the second stage of labor can be identified: protracted descent, arrest of descent, and failure of descent. All abnormalities have a strong association with cephalopelvic disproportion but may also occur in the presence of maternal obesity, uterine infection, excessive sedation, and fetal malpositions. Interpretation of the progress of fetal descent must be made in the context of other clinically discernable events and observations. These include fetal size, position, attitude, and degree of cranial molding and related evaluations of pelvic architecture and capacity to accommodate the fetus, uterine contractility, and fetal well-being. Oxytocin infusion can often resolve an arrest or failure of descent or a protracted descent caused by an inhibitory factor, such as a dense neuraxial block. It should be used only if thorough assessment of fetopelvic relationships reveals a low probability of cephalopelvic disproportion. The value of forced Valsalva pushing, fundal pressure, and routine episiotomy has been questioned. They should be used selectively and where indicated.

Labor curves based on cervical dilatation over time and their accuracy and effectiveness: A systematic scoping review.

OBJECTIVES: This systematic scoping review was conducted to 1) identify and describe labor curves that illustrate cervical dilatation over time; 2) map any evidence for, as well as outcomes used to evaluate the accuracy and effectiveness of the curves; and 3) identify areas in research that require further investigation. METHODS: A three-step systematic literature search was conducted for publications up to May 2023. We searched the Medline, Maternity & Infant Care, Embase, Cochrane Library, Epistemonikos, CINAHL, Scopus, and African Index Medicus databases for studies describing labor curves, assessing their effectiveness in improving birth outcomes, or assessing their accuracy as screening or diagnostic tools. Original research articles and systematic reviews were included. We excluded studies investigating adverse birth outcomes retrospectively, and those investigating the effect of analgesia-related interventions on labor progression. Study eligibility was assessed, and data were extracted from included studies using a piloted charting form. The findings are presented according to descriptive summaries created for the included studies. RESULTS AND IMPLICATIONS FOR RESEARCH: Of 26,073 potentially eligible studies, 108 studies were included. Seventy-three studies described labor curves, of which ten of the thirteen largest were based mainly on the United States Consortium on Safe Labor cohort. Labor curve endpoints were 10 cm cervical dilatation in 69 studies and vaginal birth in 4 studies. Labor curve accuracy was assessed in 26 studies, of which all 15 published after 1986 were from low- and middle-income countries. Recent studies of labor curve accuracy in high-income countries are lacking. The effectiveness of labor curves was assessed in 13 studies, which failed to prove the superiority of any curve. Patient-reported health and well-being is an underrepresented outcome in evaluations of labor curves. The usefulness of labor curves is still a matter of debate, as studies have failed to prove their accuracy or effectiveness.

Noninvasive factors predicting the maintenance of pregnancy for more than 4 weeks after rescue cerclage in singleton pregnancies with cervical dilatation and prolapsed membrane.

Studies on noninvasive factors and predicting the maintenance of pregnancy, and those comparing the usefulness of these factors with invasive amniotic fluid markers in predicting the maintenance of pregnancy following rescue cerclage, are lacking. Therefore, this study aimed to determine whether C-reactive protein (CRP) levels, White blood cell (WBC) count, absolute neutrophil count (ANC), and platelet-to-lymphocyte ratio (PLR) in maternal blood, which are noninvasive and readily available clinical markers, can predict the maintenance of pregnancy following rescue cerclage in patients with cervical insufficiency (CI). A total of 142 singleton pregnant women (15-28 wk) who underwent rescue cerclage for CI were retrospectively evaluated. The interleukin (IL)-6 concentration in the amniotic fluid; CRP levels, WBC count, ANC, and PLR in the maternal peripheral blood; and degree of cervical dilatation were evaluated before cerclage. The primary outcome was whether the pregnancy was maintained for >4 weeks after rescue cerclage. Among the 142 patients, prolonged pregnancy for >4 weeks following emergent cerclage was observed in 107 (75.35%), while 35 (24.65%) gave birth within 4 weeks. This study demonstrated that the degree of cervical dilatation at diagnosis; WBC count, ANC, and CRP levels in the maternal peripheral blood; and IL-6 concentration in the amniotic fluid significantly differed between the successful and failure groups (all P < .05). The area under the curve (AUC) of the amniotic fluid IL-6 concentration was .795 for the prediction of spontaneous preterm birth within 4 weeks after rescue cerclage. Additionally, the AUC of the CRP level, cervical dilatation, WBC count, ANC, and PLR were .795, .703, .695, .682, and .625, respectively. These findings suggest that the preoperative CRP levels can be considered a useful noninvasive marker comparable to amniotic fluid IL-6 concentration for identifying pregnant women with CI at high risk of spontaneous preterm birth following rescue cerclage.

Effects of Virtual Reality Interventions on the Parameters of Normal Labor: A Systematic Review and Meta-Analysis of Randomized Controlled Trials. A Meta-Analysis of Virtual Reality Interventions on the Parameters of Normal Labor.

BACKGROUND: Clinical and experimental studies on virtual reality have shown that this easy-to-use and non-invasive method is a safe and effective strategy during normal labor. AIM: This study aims to analyze the effects of virtual reality (VR) interventions on some of the parameters of normal labor. DESIGN: Systematic review and meta-analysis. METHOD: Higher Education Council National Thesis Center, Scopus, PubMed, Google Scholar, and Science Direct databases were systematically searched for randomized controlled trials that administered VR to the intervention group but not to the control group and were published through January 2022. RevMan software was used to analyze the meta-analysis data. Pain, anxiety, satisfaction, and the duration of the first and second stages of labor were assessed as outcomes of normal labor. RESULTS: Seven randomized controlled trials, with a total of 756 women in total, met the inclusion criteria. Virtual reality interventions significantly reduced pain scores when cervical dilatation was ≤4 cm (MD = -0.43, 95% expansion here (CI [-0.65, -0.21], p < .001) and ≥9 cm (SMD = -1.91, 95% CI [-2.56, -1.26], p < .001). Anxiety scores significantly decreased (SMD = -1.08, 95% CI [-1.75, 0.41], p < .001), and childbirth satisfaction significantly increased (MD = 11.24, 95% CI [2.17, 20.30], p < .001) in the VR intervention groups. Finally, when compared to the control groups, the duration of the first stage of labor (SMD = -0.53, 95% CI [-0.83, -0.22], p < .01) and the second stage of labor (MD = -0.39, 95% CI [-0.76, -0.02], p = .001) were significantly decreased in the VR intervention groups. CONCLUSIONS: Virtual reality interventions are effective methods to reduce pain, anxiety, and the duration of the first and second stages of labor and to increase satisfaction with normal labor.

Transvaginal cerclage for prevention of preterm birth in twin pregnancies with cervical dilatation or shortening: A prospective observational study.

OBJECTIVE: To investigate the efficacy of transvaginal cerclage in twin pregnancies with cervical shortening, and to narrow the threshold cervical length for transvaginal cerclage. METHODS: This is a prospective cohort study and 177 twin pregnancies with asymptomatic cervical dilatation or cervical length of 15 mm or less between 16+0 and 25+6 weeks of pregnancy were included. Patients independently chose either transvaginal cerclage (n = 129) or no cerclage treatment (n = 48) after being consulted on the risk and potential benefit of transvaginal cerclage. The primary outcome measures were gestational age at delivery and neonatal survival rate. RESULTS: Compared with the no cerclage group, the cerclage group exhibited a higher gestational age at delivery (32.1 ± 4.5 vs 28.3 ± 6.2 weeks, P < 0.001) and a higher neonatal survival rate (86.4% vs 47.9%, P < 0.001). Subgroup analysis showed that in twin pregnancies with cervical dilatation or cervical length less than 10 mm, the cerclage group had significantly higher gestational age at delivery (31.3 ± 4.6 vs 23.4 ± 4.3 weeks, P < 0.001) and a higher neonatal survival rate (123 [85.4%] vs 4 [9.1%], P < 0.001) than the no cerclage group, but in twins when cervical length was 10-15 mm, the two measures were similar between the two groups. CONCLUSION: Transvaginal cerclage may provide benefits for twins when cervical dilatation or cervical length is less than 10 mm, but its efficacy might not extend to twins when the cervical length is 10-15 mm. Further evidence is needed to confirm the efficacy of transvaginal cerclage for twin pregnancies with a short cervix.

Evaluación de la dilatación cervical en simuladores comparada con una herramienta visual: estudio aleatorizado / Cervical dilation assessment in simulators compared to a visual tool: A randomized study / Avaliação da dilatação cervical em simuladores comparada a uma ferramenta visual: estudo randomizado

Objetivo: comprobar la tasa de evaluación correcta mediante la comparación visual directa de las medidas de dilatación cervical en modelos de cuello uterino de consistencia dura. Método: estudio aleatorizado abierto con 63 estudiantes de obstetricia a los que se les asignó usar o no la comparación visual directa con una guía de dilatación. Los estudiantes estimaron de forma ciega la dilatación cervical en simuladores con diferentes dilataciones. El resultado primario fue la tasa de evaluación correcta. Resultados: los estudiantes realizaron 441 pruebas. Se observó una mayor tasa de evaluación correcta en el grupo experimental que en el grupo control (47,3% versus 27,2%; p < 0,001; Odds Ratio = 2,41; intervalo de confianza del 95% = 1,62-3, 58). Conclusión: la comparación visual directa aumentó la precisión de la evaluación de la dilatación cervical en modelos de simulación de cuello, lo que podría ser beneficioso en el entrenamiento de laboratorio. Registro Brasileño de Ensayos Clínicos n.º U1111-1210-2389.

Objective: to verify the correct assessment rate when using direct visual comparison in the cervical dilation measures in hard-consistency cervix simulation models. Method: an open-label and randomized study conducted with 63 Obstetrics students that were designated either to use direct visual comparison in a dilation guide or not. The students estimated cervical dilation blindly in simulators with different dilations. The primary outcome was the correct assessment rate. Results: the students performed 141 tests. A higher correct assessment rate was found in the Experimental Group than in the Control Group (47.3% versus 27.2%; p<0.001; Odds Ratio = 2.41; 95% Confidence Interval = 1.62-3.58). Conclusion: the direct visual comparison increased precision of the cervical dilation assessment in cervix simulation models, with the possibility of being beneficial in laboratory training. Brazilian Registry of Clinical Trials No. U1111-1210-2389.

Objetivo: verificar a taxa de avaliação correta com o uso da comparação visual direta nas medidas de dilatação cervical em modelos de simulação de colo com consistência dura. Método: estudo randomizado aberto com 63 estudantes de obstetrícia que foram designados para usar comparação visual direta em um guia de dilatação ou não. Os estudantes estimaram cegamente a dilatação cervical em simuladores com diferentes dilatações. O desfecho primário foi a taxa de avaliação correta. Resultados: os estudantes realizaram 441 testes. Foi encontrada maior taxa de avaliação correta no grupo experimental do que no grupo controle (47,3% versus 27,2%; p <0,001; Odds Ratio = 2,41; intervalo de confiança de 95% = 1,62-3,58). Conclusão: a comparação visual direta aumentou a precisão da avaliação da dilatação cervical em modelos de simulação de colo, podendo ser benéfica no treinamento em laboratório. Registro Brasileiro de Ensaios Clínicos nº U1111-1210-2389.

Comparison of Labor Curves Between Spontaneous and Induced Labor.

OBJECTIVE: To compare the labor curve between individuals with induced labor and those undergoing spontaneous labor. METHODS: This was a secondary analysis of the Consortium on Safe Labor database, including nulliparous and multiparous individuals with singleton vertex pregnancy who delivered vaginally after spontaneous labor or induction of labor at term. Labor that resulted in uterine rupture and neonates with a 5-minute Apgar scores less than 7, birth injury, or neonatal intensive care unit admission was excluded. We modeled the course of cervical dilation using repeated-measures analysis with a polynomial function. We compared traverse time , defined as the elapsed time between two given dilation measures, between induced and spontaneous labor using interval-censored regression. RESULTS: Of 46,835 nulliparous individuals, 18,576 and 28,259 underwent induced and spontaneous labor, respectively. Of 77,503 multiparous individuals, 29,684 and 47,819 underwent induced and spontaneous labor, respectively. The start of the active phase on the labor curve was 6 cm in induced labor, regardless of parity. In nulliparous individuals, induced labor compared with spontaneous labor had a significantly shorter traverse time from 6 to 10 cm (median 1.8 hours [5th-95th percentile 0.4-8.6 hours] vs 2.3 hours [5th-95th percentile 0.6-9.4 hours]; P <.01). In multiparous individuals, induced labor compared with spontaneous labor had a significantly shorter traverse time from 6 to 10 cm (median 0.9 hours [5th-95th percentile 0.1-6.0 hours] vs 1.4 hours [5th-95th percentile 0.3-7.9 hours]; P <.01). CONCLUSION: Similar to spontaneous labor, the start of the active phase of induced labor was at 6 cm of dilation. Comparatively, induced labor had a shorter active phase than spontaneous labor. These findings suggest that the current criteria for active phase arrest provided by the American College of Obstetricians and Gynecologists do not need to be lengthened for individuals in induced labor.

The purple line and its association with cervical dilatation in labour: A systematic review and meta-analysis.

BACKGROUND: There is a growing body of evidence that the presence and length of the purple line could represent a non-invasive method of estimating and determining labour progress. OBJECTIVES: The primary outcome was to provide a systematic review and meta-analysis on the association between the purple line length and cervical dilatation in active labour. The secondary outcome was to determine the association between the purple line length and the fetal head descent, and to calculate the pooled mean length of the purple line at a cervical dilatation of 3-4 cm and at a cervical dilatation of 9-10 cm. SEARCH STRATEGY: We searched the Medline, Scopus, Cochrane Central Register of Controlled Trials (CENTRAL), Clinical Trials.gov and Cochrane Pregnancy and Childbirth's Trials Register databases from inception till March 25, 2023. SELECTION CRITERIA: We included observational studies of pregnant women in active first stage of labour who had their labour progress assessed with the use of regular vaginal examinations and who had the occurrence recorded and length of the purple line measured at the same time. DATA COLLECTION AND ANALYSIS: Two reviewers independently evaluated study eligibility. We used the random effects and fixed effects model for meta-analysis. MAIN RESULTS: There were six eligible studies included in the systematic review that reported on 982 women in total with the purple line appearing in 760 (77.3%) of cases. We found a moderate positive pooled correlation between the purple line length with cervical dilatation (r = +0.64; 95%CI: 0.41-0.87) and fetal head descent (r = +0.50; 95%CI: 0.32-0.68). For women either in spontaneous or induced labour, the pooled mean length of the purple line was more than 9.4 cm when the cervical dilatation was 9-10 cm, whereas it was more than 7.3 cm when the cervical dilatation was 3-4 cm. CONCLUSIONS: The purple line is a non-invasive method that may potentially be used as an adjunct in labour progress assessment.

Cervical cerclage for prevention of preterm birth and adverse perinatal outcome in twin pregnancies with short cervical length or cervical dilatation: A systematic review and meta-analysis.

BACKGROUND: The optimal approach to prevent preterm birth (PTB) in twins has not been fully established yet. Recent evidence suggests that placement of cervical cerclage in twin pregnancies with short cervical length at ultrasound or cervical dilatation at physical examination might be associated with a reduced risk of PTB. However, such evidence is based mainly on small studies thus questioning the robustness of these findings. The aim of this systematic review was to determine the role of cervical cerclage in preventing PTB and adverse maternal or perinatal outcomes in twin pregnancies. METHODS AND FINDINGS: Key databases searched and date of last search: MEDLINE, Embase, and CINAHL were searched electronically on 20 April 2023. Eligibility criteria: Inclusion criteria were observational studies assessing the risk of PTB among twin pregnancies undergoing cerclage versus no cerclage and randomized trials in which twin pregnancies were allocated to cerclage for the prevention of PTB or to a control group (e.g., placebo or treatment as usual). The primary outcome was PTB <34 weeks of gestation. The secondary outcomes were PTB <37, 32, 28, 24 weeks of gestation, gestational age at birth, the interval between diagnosis and birth, preterm prelabor rupture of the membranes (pPROM), chorioamnionitis, perinatal loss, and perinatal morbidity. Subgroup analyses according to the indication for cerclage (short cervical length or cervical dilatation) were also performed. Risk of bias assessment: The risk of bias of the included randomized controlled trials (RCTs) was assessed using the Revised Cochrane risk-of-bias tool for randomized trials, while that of the observational studies using the Newcastle-Ottawa scale (NOS). Statistical analysis: Summary risk ratios (RRs) of the likelihood of detecting each categorical outcome in exposed versus unexposed women, and (b) summary mean differences (MDs) between exposed and unexposed women (for each continuous outcome), with their 95% confidence intervals (CIs) were computed using head-to-head meta-analyses. Synthesis of the results: Eighteen studies (1,465 twin pregnancies) were included. Placement of cervical cerclage in women with a twin pregnancy with a short cervix at ultrasound or cervical dilatation at physical examination was associated with a reduced risk of PTB <34 weeks of gestation (RR: 0.73, 95% CI [0.59, 0.91], p = 0.005 corresponding to a 16% difference in the absolute risk, AR), <32 (RR: 0.69, 95% CI [0.57, 0.84], p < 0.001; AR: 16.92%), <28 (RR: 0.54, 95% [CI 0.43, 0.67], 0.001; AR: 18.29%), and <24 (RR: 0.48, 95% CI [0.23, 0.97], p = 0.04; AR: 15.57%) weeks of gestation and a prolonged gestational age at birth (MD: 2.32 weeks, 95% [CI 0.99, 3.66], p < 0.001). Cerclage in twin pregnancy with short cervical length or cervical dilatation was also associated with a reduced risk of perinatal loss (RR: 0.38, 95% CI [0.25, 0.60], p < 0.001; AR: 19.62%) and composite adverse outcome (RR: 0.69, 95% CI [0.53, 0.90], p = 0.007; AR: 11.75%). Cervical cerclage was associated with a reduced risk of PTB <34 weeks both in women with cervical length <15 mm (RR: 0.74, 95% CI [0.58, 0.95], p = 0.02; AR: 29.17%) and in those with cervical dilatation (RR: 0.68, 95% CI [0.57, 0.80], p < 0.001; AR: 35.02%). The association between cerclage and prevention of PTB and adverse perinatal outcomes was exclusively due to the inclusion of observational studies. The quality of retrieved evidence at GRADE assessment was low. CONCLUSIONS: Emergency cerclage for cervical dilation or short cervical length <15 mm may be potentially associated with a reduction in PTB and improved perinatal outcomes. However, these findings are mainly based upon observational studies and require confirmation in large and adequately powered RCTs.

Oxycodone does not affect placental circulatory physiology during the early first stage of labor-A randomized trial.

INTRODUCTION: Opioids are used for pain relief during the first stage of labor. Oxycodone can cause maternal hypotension that may modify utero- and fetoplacental circulatory physiology. We hypothesized that maternal intravenous (i.v.) oxycodone has no detrimental effect on utero- and fetoplacental hemodynamics during the early first stage of labor. MATERIAL AND METHODS: Twenty-two parturients requiring pain relief during the first stage of labor were randomized in a double-blinded and placebo-controlled study. By Doppler ultrasonography, both uterine artery (Ut) and umbilical vein (UV) volume blood flows (Q), Ut pulsatility index (PI), and Ut vascular resistance (RUt) were calculated. Blood flow velocity waveforms were obtained between uterine contractions. After baseline measurements, women received oxycodone 0.05 mg/kg or a placebo intravenous. Doppler ultrasonography was repeated up to 120 min after the first drug administration. The second dose of oxycodone 0.05 mg/kg was allowed at 60 min to all parturients with contraction pain ≥5/10. Maternal plasma samples were collected at each study phase and after delivery with umbilical cord plasma samples, to measure oxycodone concentrations. CLINICALTRIALS: gov identifier (NCT no. NCT02573831). RESULTS: At baseline, mean QUt and QUV did not differ significantly between the placebo-first (478 mL/min and 57 mL/min/kg) and the oxycodone-first (561 mL/min and 71 mL/min/kg) groups. In addition, RUt and Ut PI were comparable between the groups. Following oxycodone at 60 min, mean QUt and QUV (714 mL/min and 52 mL/min/kg) were similar to the placebo-first (520 mL/min and 55 mL/min/kg) group. Furthermore, all the measured parameters were comparable to the baseline values. At 60 min after the first study drug administration, all the parturients in the placebo-first group needed intravenous oxycodone 0.05 mg/kg. At 120 min, we found no statistically significant change in any of the measured parameters. No significant correlation was found between maternal oxycodone concentration and QUt or QUV. Furthermore, newborn oxycodone concentration did not correlate with QUV. CONCLUSIONS: Oxycodone did not have any detrimental effect on either utero- or fetoplacental circulatory physiology during the early first stage of labor. Maternal plasma oxycodone did not correlate with utero- and fetoplacental hemodynamics. No correlation was found between newborn oxycodone concentration and fetoplacental hemodynamics.

New insights on labor progression: a systematic review.

The past 20 years witnessed an invigoration of research on labor progression and a change of thinking regarding normal labor. New evidence is emerging, and more advanced statistical methods are applied to labor progression analyses. Given the wide variations in the onset of active labor and the pattern of labor progression, there is an emerging consensus that the definition of abnormal labor may not be related to an idealized or average labor curve. Alternative approaches to guide labor management have been proposed; for example, using an upper limit of a distribution of labor duration to define abnormally slow labor. Nonetheless, the methods of labor assessment are still primitive and subject to error; more objective measures and more advanced instruments are needed to identify the onset of active labor, monitor labor progression, and define when labor duration is associated with maternal/child risk. Cervical dilation alone may be insufficient to define active labor, and incorporating more physical and biochemical measures may improve accuracy of diagnosing active labor onset and progression. Because the association between duration of labor and perinatal outcomes is rather complex and influenced by various underlying and iatrogenic conditions, future research must carefully explore how to integrate statistical cut-points with clinical outcomes to reach a practical definition of labor abnormalities. Finally, research regarding the complex labor process may benefit from new approaches, such as machine learning technologies and artificial intelligence to improve the predictability of successful vaginal delivery with normal perinatal outcomes.

The evolution of the labor curve and its implications for clinical practice: the relationship between cervical dilation, station, and time during labor.

The assessment of labor progress is germane to every woman in labor. Two labor disorders-arrest of dilation and arrest of descent-are the primary indications for surgery in close to 50% of all intrapartum cesarean deliveries and are often contributing indications for cesarean deliveries for fetal heart rate abnormalities. Beginning in 1954, the assessment of labor progress was transformed by Friedman. He published a series of seminal works describing the relationship between cervical dilation, station of the presenting part, and time. He proposed nomenclature for the classification of labor disorders. Generations of obstetricians used this terminology and normal labor curves to determine expected rates of dilation and fetal descent and to decide when intervention was required. The analysis of labor progress presents many mathematical challenges. Clinical measurements of dilation and station are imprecise and prone to variation, especially for inexperienced observers. Many interrelated factors influence how the cervix dilates and how the fetus descends. There is substantial variability in when data collection begins and in the frequency of examinations. Statistical methods to account for these issues have advanced considerably in recent decades. In parallel, there is growing recognition among clinicians of the limitations of using time alone to assess progress in cervical dilation in labor. There is wide variation in the patterns of dilation over time and most labors do not follow an average dilation curve. Reliable assessment of labor progression is important because uncertainty leads to both over-use and under-use of cesarean delivery and neither of these extremes are desirable. This review traces the evolution of labor curves, describes how limitations are being addressed to reduce uncertainty and to improve the assessment of labor progression using modern statistical techniques and multi-dimensional data, and discusses the implications for obstetrical practice.

Use of External Uterine Electromyography Across Stage I Labor.

INTRODUCTION: Highly sensitive, external uterine electromyography (EMG) measures myometrial electrical activity and is noninvasive compared with the clinical intrauterine pressure catheter. Most experimental studies have measured EMG in 30-minute epochs, limiting the utility of this instrumentation in intrapartum clinical practice. To test proof of concept, surface uterine EMG contraction activity was continuously collected throughout the first stage of labor from healthy women at term gestation with (n = 3) and without (n = 1) epidural or combined spinal-epidural analgesia for a maximal length of 11 hours and 24 minutes. METHODS: EMG activity was recorded concurrently with tocodynamometer (toco) signals, using a pair of electrodes on the left and right sides of the maternal umbilicus with grounds attached to both hips of the reclining woman in labor. The preamplifier cutoff frequency settings were appropriate to monitor smooth muscle contraction in labor, with the analog high-pass filter set at 0.05 Hz and the low-pass filter at 1.50 Hz. Signals were sampled at 100 Hz, transmitted to a computer, and visualized by Chart 4.2 software. EMG data from epochs at baseline, during the pre-epidural fluid bolus and at the 60-minute post-epidural test dose, and at 3, 5, 6, and 8 cm dilatation were analyzed for burst power spectrum peak frequency (Hz), burst power spectrum amplitude (mV2 ), and burst duration (seconds). RESULTS: Uterine EMG contractile bursts were preceded and followed by a stable baseline and coincided with toco contractions. Movement artifacts were negligible, and large movement artifacts were easily distinguishable. The EMG bursts and toco contractions remained clearly identifiable, even when one woman without epidural analgesia stood beside the bed laboring for approximately 10 minutes. Burst spectral components fell within the expected 0.34-to-1.00 Hz range for term labor. DISCUSSION: High-quality data demonstrate that EMG instrumentation effectively and accurately measures uterine contraction parameters across the first stage of term labor.

Cervical dilatation at diagnosis of active phase of labour determines the mode of delivery and peripartum outcomes: a retrospective study in a single tertiary centre in Malaysia.

BACKGROUND: There is an increasing trend of Caesarean section rate in Malaysia. Limited evidence demonstrated the benefits of changing the demarcation of the active phase of labour. METHODS: This was a retrospective study of 3980 singletons, term pregnancy, spontaneous labouring women between 2015 and 2019 comparing outcomes between those with cervical dilation of 4 versus 6 cm at diagnosis of the active phase of labour. RESULTS: A total of 3403 (85.5%) women had cervical dilatation of 4 cm, and 577 (14.5%) at 6 cm upon diagnosis of the active phase of labour. Women in 4 cm group were significantly heavier at delivery (p = 0.015) but significantly more multiparous women were in 6 cm group (p < 0.001). There were significantly fewer women in the 6 cm group who needed oxytocin infusion (p < 0.001) and epidural analgesia (p < 0.001) with significantly lower caesarean section rate (p < 0.001) done for fetal distress and poor progress (p < 0.001 both). The mean duration from diagnosis of the active phase of labour until delivery was significantly shorter in the 6 cm group (p < 0.001) with lighter mean birth weight (p = 0.019) and fewer neonates with arterial cord pH < 7.20 (p = 0.047) requiring neonatal intensive care unit admissions (p = 0.01). Multiparity (AOR = 0.488, p < 0.001), oxytocin augmentation (AOR = 0.487, p < 0.001) and active phase of labour diagnosed at 6 cm (AOR = 0.337, p < 0.001) reduced the risk of caesarean delivery. Caesarean delivery increased the risk of neonatal intensive care admission by 27% (AOR = 1.73, p < 0.001). CONCLUSIONS: Active phase of labour at 6 cm cervical dilatation is associated with reduced primary caesarean delivery rate, labour intervention, shorter labour duration and fewer neonatal complications.

Cervical dilation assessment in simulators compared to a visual tool: A randomized study. / Evaluación de la dilatación cervical en simuladores comparada con una herramienta visual: estudio aleatorizado.

OBJECTIVE: to verify the correct assessment rate when using direct visual comparison in the cervical dilation measures in hard-consistency cervix simulation models. METHOD: an open-label and randomized study conducted with 63 Obstetrics students that were designated either to use direct visual comparison in a dilation guide or not. The students estimated cervical dilation blindly in simulators with different dilations. The primary outcome was the correct assessment rate. RESULTS: the students performed 141 tests. A higher correct assessment rate was found in the Experimental Group than in the Control Group (47.3% versus 27.2%; p<0.001; Odds Ratio = 2.41; 95% Confidence Interval = 1.62-3.58). CONCLUSION: the direct visual comparison increased precision of the cervical dilation assessment in cervix simulation models, with the possibility of being beneficial in laboratory training. Brazilian Registry of Clinical Trials No. U1111-1210-2389.

Effects of epidural analgesia at 1 cm cervical dilatation on labor interventions in full-term primigravida: A retrospective cohort study.

OBJECTIVE: This study aimed to investigate the effects of epidural analgesia administered as early as cervical dilatation of 1 cm on labor interventions and maternal and neonatal outcomes. METHODS: This retrospective research recruited 1007 full-term primigravidas, who were distributed to two separate cohorts for eligibility: epidural analgesia 1 (cervical dilatation = 1 cm) and epidural analgesia 2 (cervical dilatation >1 cm). Labor interventions (artificial rupture of membranes and oxytocin administration) and duration of labor were the primary outcomes. RESULTS: The effect of initiation timing of epidural analgesia on artificial membrane rupture was not statistically significant (adjusted odds ratio [OR]: 0.85 [0.58-1.24], p > 0.05). Less oxytocin was used in the epidural analgesia 2 group compared with the epidural analgesia 1 group (the adjusted OR: 0.68 [0.49-0.95], p < 0.05). There were no significant differences in the median time to latent phase of labor, active phase of labor, second, and third stages of labor (p > 0.05). There were no significant differences in maternal and neonatal outcomes between the epidural analgesia 1 group and the epidural analgesia 2 group. CONCLUSION: Epidural analgesia could be administered at cervical dilatation = 1 cm.

The latent phase of labor.

The latent phase of labor extends from the initiation of labor to the onset of the active phase. Because neither margin is always precisely identifiable, the duration of the latent phase often can only be estimated. During this phase, the cervix undergoes a process of rapid remodeling, which may have begun gradually weeks before. As a consequence of extensive changes in its collagen and ground substance, the cervix softens, becomes thinner and dramatically more compliant, and may dilate modestly. All of these changes prepare the cervix for the more rapid dilatation that will occur during the active phase to follow. For the clinician, it is important to recognize that the latent phase may normally extend for many hours. The normal limit for the duration of the latent phase should be considered to be approximately 20 hours in a nullipara and 14 hours in a multipara. Factors that have been associated with a prolonged latent phase include deficient prelabor or intrapartum cervical remodeling, excessive maternal analgesia or anesthesia, maternal obesity, and chorioamnionitis. Approximately 10% of women with a prolonged latent phase are actually in false labor, and their contractions eventually abate spontaneously. The management of a prolonged latent phase involves either augmenting uterine activity with oxytocin or providing a sedative-induced period of maternal rest. Both are equally effective in advancing the labor to active phase dilatation. A very long latent phase may be a harbinger of other labor dysfunctions.

ED90 of Sufentanil in Epidural Initiation for Labor Analgesia in Latent Phase and Active Phase During the First Labor Stage.

BACKGROUND: The standard solutions for epidural labor analgesia include both local anesthetics and opioids. The concept of the standard epidural use of local anesthetics in labor analgesia has shifted from high concentrations to high volumes with low concentrations. However, the optimal dosage of opioids needed to initiate and maintain epidural labor analgesia in different phases during the first labor stage has rarely been studied. OBJECTIVE: The present study aimed to determine the optimal sufentanil dose for epidural initiation in the latent and active phases during the first stage of labor. STUDY DESIGN: A prospective, double-blind, sequential dose-finding study. SETTING: A Class A tertiary obstetrics and gynecology hospital. METHODS: The study included 80 nulliparae with cervical dilatation of 2-4 cm and 5-6 cm, with 40 nulliparae in each group. A research dose of sufentanil combined with ropivacaine 13 mg in epidural initiation with a volume of 15 mL was administered to the puerperant. A 1-microgram sufentanil dose and a 2.5-micrograms sufentanil dose were used for the first puerperant of each group. The dose of sufentanil for the subsequent puerperant was determined by the response of the previous puerperant according to the biased coin up-and-down design in each trial. The primary outcome was a visual analog scale score of <= 3 at 15, 30, and 45 minutes after epidural administration, including the given dose of sufentanil. According to the response of each puerperant, the 90% effective doses and their 95% confidence intervals were estimated by isotonic regression and bootstrapping according to the response of each puerperant. RESULTS: The 90% effective doses of sufentanil for puerperants were 1.91 micrograms (95% confidence intervals 1.82-2.35 micrograms) and 4.90 micrograms (95% confidence intervals 4.82-5.35 micrograms) in epidural initiation in the latent and active phases, respectively. The 90% effective doses were 62.5% (95% confidence intervals 50.8-64.0%) lower in the latent phase than that in the active phase during the first stage of labor. LIMITATIONS: Both spontaneous labor and induced labor were included in this study, and the degree of pain in these 2 types of labor is different. Further, only nulliparae were recruited in the study. CONCLUSIONS: Different sufentanil doses should be adopted in epidural initiation in different phases during the first stage of labor due to the large differences in the demand for sufentanil.

Use of a pocket-device point-of-care ultrasound to assess cervical dilation in labor: correlation and patient experience.

OBJECTIVES: To estimate the correlation of cervical dilation between pocket-device point-of-care transperineal ultrasound (TPUS) and digital cervical examination (DCE). METHODS: Laboring pregnant individuals ≥37 weeks of gestation presenting were prospectively evaluated for cervical dilation with a handheld pocket-sized ultrasound (Butterfly iQ+®) applied to the perineum, with a blinded DCE directly following. Subjects completed a survey to rate pain and for any preference from the examinations. To detect a moderate correlation (r=0.5) between TPUS and DCE, with an alpha of 0.05 and power of 80%, a sample size of 30 examinations were needed. RESULTS: From April 2022 to July 2022, 30 pregnant individuals were assessed. The median cervical dilation by TPUS vs. DCE was 5.1 and 5 cm, respectively, with a Pearson's correlation coefficient, r=0.86 (95% CI 0.72 to 0.93), p<0.001. Transperineal ultrasound had a significantly less pain score than DCE, median pain score 0 vs. 2 for TPUS and DCE respectively, p<0.001. All individuals preferred the TPUS over the DCE. CONCLUSIONS: Measurement of cervical dilation using a pocket-device point-of-care TPUS has a strong positive correlation with DCE and offers a non-invasive, convenient alternative to traditional digital exams in term, laboring patients.