Normal labor curve in twin gestation

A Trial of Labor after Cesarean Section with a Macrosomic Neonate. Is It Safe?

OBJECTIVE

This study aimed to determine whether a trial of labor after cesarean section (TOLAC) with a macrosomic neonate is associated with adverse outcomes.

STUDY DESIGN

A retrospective cohort study was conducted in a population motivated for TOLAC. Women attempting TOLAC with a neonatal birth weight >4,000 g were compared with women attempting TOLAC with neonatal birth weights between 3,500 and 4,000 g. The primary outcome was TOLAC success. Secondary outcomes included mode of delivery, uterine rupture, postpartum hemorrhage (PPH), shoulder dystocia, obstetric anal sphincter injury (OASI), Apgar's score <7 at 5 minutes, and umbilical artery pH <7.1. Data were analyzed using Fisher's exact test and Chi-square test.

RESULTS

Overall, 375 women who underwent TOLAC with a neonate weighing >4,000 g comprised the study group. One thousand seven hundred and eighty-three women attempting TOLAC with a neonate weighing 3,500 to 4,000 g comprised the control group. There were no clinically significant differences between the groups for maternal age, gestational age, parity, and vaginal birth after cesarean (VBAC) rate. There were no significant differences in the rates of successful TOLAC (94 vs. 92.3%, p = 0.2, odds ratio [OR] = 0.8, 95% confidence interval [CI]: 0.5, 1.2), operative vaginal delivery (7.4 vs. 5.3%, p = 0.18, OR = 0.7, 95% CI: 0.4, 1.1), uterine rupture (0.4 vs. 0%, p = 0.6), PPH (3.2 vs. 2.3%, p = 0.36, OR = 1.4, 95% CI: 0.7, 2.7), OASI (0.8 vs. 0.2%, p = 0.1, OR = 3.6, 95% CI: 0.8, 1.6), Apgar's score <7 at 5 minutes (0 vs. 0.4%, p = 0.37), and umbilical artery pH <7.1 (0.5 vs. 0.7%, p = 1.0, OR = 0.73, 95% CI: 0.2, 3.2). Women with a neonate weighing >4,000 g had a significantly increased risk of shoulder dystocia (4 vs. 0.4%, p < 0.05, OR = 9.2 95% CI: 3.9, 22) CONCLUSION:  Women attempting TOLAC with a macrosomic neonate are not at increased risk for failed TOLAC, operative vaginal delivery, uterine rupture, PPH, or OASI but are at risk of shoulder dystocia. This information may aid in prenatal counseling for women considering TOLAC with a macrosomic fetus.

KEY POINTS

· TOLAC with fetal macrosomia does not increase the risk of uterine rupture.. · TOLAC with fetal macrosomia is associated with high chances of VBAC.. · TOLAC with fetal macrosomia is not associated with adverse neonatal outcomes..

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.

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.

Partogram of Grandmultiparous Parturients: A Multicenter Cohort Study

Sparse and conflicting data exist regarding the normal partogram of grand-multiparous (GMP, defined as parity of 6+) parturients. Customized partograms may potentially lower cesarean delivery rates for protraction disorders in this population. In this study, we aim to construct a normal labor curve of GMP women and compare it to the multiparous (MP, defined as parity of 2-5) partogram. We conducted a multicenter retrospective cohort analysis of deliveries between the years 2003 and 2019. Eligible parturients were the trials of labor of singletons ≥37 + 0 weeks in cephalic presentation with ≥2 documented cervical examinations during labor. Exclusion criteria were elective cesarean delivery without a trial of labor, preterm labor, major fetal anomalies, and fetal demise. GMP comprised the study group while the MP counterparts were the control group. A total of 78,292 deliveries met the inclusion criteria, comprising 10,532 GMP and 67,760 MP parturients. Our data revealed that during the first stage of labor, cervical dilation progressed at similar rates in MPs and GMPs, while head descent was a few minutes faster in GMPs compared to MPs, regardless of epidural anesthesia. The second stage of labor was faster in GMPs compared to MPs; the 95th percentile of the second stage duration of GMPs (48 min duration) was 43 min less than that of MPs (91 min duration). These findings remained similar among deliveries with and without epidural analgesia or labor induction. We conclude that GMPs' and MPs' cervical dilation progression in the active phase of labor was similar, and the second stage of labor was shorter in GMPs, regardless of epidural use. Thus, GMPs' uterus function during labor corresponds, and possibly surpasses, that of MPs. These findings indicate that health providers can use the standard partogram of the active phase of labor when caring for GMP parturients.

Trial of labor of vertex-nonvertex twins following a previous cesarean delivery

BACKGROUND

Maternal and neonatal outcomes of trial of labor after cesarean delivery of twins are similar to those of singleton trials of labor after cesarean delivery. However, previous studies did not stratify outcomes by second-twin presentation on admission to labor.

OBJECTIVE

To examine maternal and neonatal outcomes following trial of labor after cesarean delivery in twins with vertex-nonvertex presentation.

STUDY DESIGN

A retrospective multicenter study was conducted including data on deliveries occurring between the years 2005 and 2020. We included trials of labor after a previous cesarean delivery (at ≥32^0/7 weeks' gestation) of twin gestations with a vertex-presenting first twin on admission to labor. The exposed group was defined as deliveries with a nonvertex second twin at admission to labor, whereas the comparison group included deliveries with a vertex second twin at admission. Only parturients who attempted vaginal delivery were included. Cases of prelabor fetal death of either twin or major fetal anomalies were excluded. The primary outcome was uterine rupture.

RESULTS

A total of 236 twin trials of labor after cesarean delivery were included, of which 128 involved nonvertex second twins and 108 a second vertex twin. Uterine rupture rates were comparable between the groups (1/128 [0.9%] vs 1/108 [0.8%]; P=1.000). Successful trial of labor after cesarean delivery of both twins occurred in 76.6% of the exposed group vs 81.5% of the comparison group, whereas cesarean delivery of both twins was performed in 21.9% of the exposed group vs 17.6% of the comparison group (P=.418; odds ratio, 1.32; confidence interval, 0.7-2.5). Two cases of cesarean delivery of the second twin occurred in the exposed group and 1 in the comparison group (1.6% vs 0.9%, respectively, P=1.000). There was no difference between the groups in maternal outcomes, including rates of postpartum hemorrhage, blood transfusion, placental abruption, thromboembolic events, and maternal fever. Neonatal outcomes were also comparable between the groups, including rates of intensive care admission and low (≤7) 5-minute Apgar scores.

CONCLUSION

Our data show that trial of labor after cesarean delivery of noncephalic second twins holds favorable maternal and neonatal outcomes, comparable with those of vertex-vertex trials of labor after cesarean delivery. Second-twin noncephalic presentation should not discourage parturients and caregivers from considering trial of labor after cesarean delivery if desired.