OBJECTIVE: Vaginal childbirth is a key risk factor for pelvic floor muscle injury and dysfunction, and subsequent pelvic floor disorders. Multiparity further exacerbates these risks. Using the rat model, validated for the studies of the human pelvic floor muscles, we have previously identified that a single simulated birth injury results in pelvic floor muscle atrophy and fibrosis. We hypothesized that multiple birth injuries would further overwhelm the muscle regenerative capacity, leading to functionally relevant pathological alterations long-term.
METHODS: Sprague-Dawley rats underwent simulated birth injury and were allowed to recover for 8 weeks before undergoing additional birth injury. Animals were sacrificed at acute (3- and 7-days post injury), subacute (21-, 28-, and 35-days post-injury), and long-term (8- and 12-weeks post-injury) time points post-second injury (N=3-8/time point), and the pubocaudalis portion of the rat levator ani complex was harvested to assess the impact of repeated birth injuries on muscle mechanical and histomorphological properties. The accompanying transcriptional changes were assessed by a customized NanoString panel. Uninjured animals were used as controls. Data with a parametric distribution were analyzed by a two-way analysis of variance followed by post hoc pairwise comparisons using Tukey\'s or Sidak\'s tests; non-parametrically distributed data were compared with Kruskal-Wallis test followed by pairwise comparisons with Dunn\'s test. Data, analyzed using GraphPad Prism v8.0, San Diego, CA, are presented as mean ± SEM or median (range).
RESULTS: Following the 1st simulated birth injury, active muscle force decreased acutely relative to uninjured controls (12.9±0.9 vs 25.98±2.1 g/mm2, P<0.01). At 4 weeks, muscle active force production recovered to baseline and remained unchanged at 8 weeks after birth injury (P>0.99). Similarly, precipitous decrease in active force was observed immediately after repeated birth injury (18.07±1.2 vs 25.98±2.1 g/mm2, P<0.05). In contrast to the functional recovery after a single birth injury, a long-term decrease in muscle contractile function was observed up to 12 weeks after repeated birth injuries (18.3±1.6 vs 25.98±2.1 g/mm2, P<0.05). Fiber size was smaller at the long-term time points after 2nd injury compared to the uninjured group (12 weeks vs uninjured control: 1485 (60.7-5000) vs 1989 (65.6-4702) μm2, P<0.0001). The proportion of fibers with centralized nuclei, indicating active myofiber regeneration, returned to baseline at 8 weeks post-1st birth injury, (P=0.95), but remained elevated as far as 12 weeks post-2nd injury (12 weeks vs uninjured control: 7.1±1.5 vs 0.84±0.13%, P<0.0001). In contrast to the plateauing intramuscular collagen content after 4 weeks post-1st injury, fibrotic degeneration increased progressively over 12 weeks after repeated injury (12 weeks vs uninjured control: 6. 7±1.1 vs 2.03±0.2%, P<0.001). Prolonged expression of pro-inflammatory genes accompanied by a greater immune infiltrate was observed after repeated compared to a single birth injury.
CONCLUSIONS: Overall, repeated birth injuries led to a greater magnitude of pathological alterations compared to a single injury, resulting in more pronounced pelvic floor muscle degeneration and muscle dysfunction in the rat model. The above provides a putative mechanistic link between multiparity and the increased risk of pelvic floor dysfunction in women.

BACKGROUND: There is a growing body of evidence indicating that second-degree tears cause both short- and long-term consequences. Very few preventative measures have been found to reduce the incidence of these tears.
OBJECTIVE: This study aimed to investigate whether the use of a perineal protection device during vaginal birth reduces severe perineal tearing (grade ≥2 tear) in primiparous women compared with routine manual perineal support.
METHODS: A single-center randomized controlled trial was conducted in Sweden from 2019 to 2021. Primiparous women at term were randomly allocated to the intervention group (n=43), where a perineal protection device was used, or to the routine care group (n=49). The primary outcome was grade of perineal tear. The secondary outcomes were vaginal and labial tearing. Continuous data were analyzed using the Student t test or Mann-Whitney U test. Dichotomous data were analyzed using the Pearson X2 test, Fisher exact test, and ordinal logistic regression.
RESULTS: Women in the intervention group had a significantly lower risk of sustaining more extensive perineal tearing than those in the control group. The use of the perineal protection device decreased the risk of grade ≥2 tears in relation to grade 0 to 1 tears (odds ratio, 0.40; 95% confidence interval, 0.17-0.94). Ordinal logistic regression analyses revealed an odds ratio of 0.36 (95% confidence interval, 0.16-0.81) per incremetn of grade injury using the perineal protection device vs routine care (P=.013). The number needed to treat using the perineal protection device was 4.3 to avoid 1 grade ≥2 tear. Women in the treatment group showed less labial tearing (P=.016). No adverse effect was detected.
CONCLUSIONS: The use of a perineal protection device reduced the risk of grade ≥2 perineal tearing by 60% and labial tearing.

OBJECTIVE: To determine the obstetric factors affecting the development of depressed skull fracture in neonates.
METHODS: This was a retrospectively cohort study on neonates born between July 2016 and August 2021. Neonates diagnosed with depressed skull fractures within one week of birth through X-ray and/or brain ultrasonography were included, and their mothers\' obstetric characteristics were reviewed.
RESULTS: There were 12 cases in 6791 live births. Five women were over 35 years old. All except two were nulliparous. Five cases were delivered from labor induction and others presented with spontaneous labor. Except for two cases, delivery occurred within an hour after full cervical dilatation. Two cases were assisted by vacuum. None displayed fetal distress signs such as low Apgar scores below 7, meconium staining, and umbilical cord pH under 7.2. All depressed fractures were found in the right parietal area. Three cases resulted in focal hyperechoic lesion in brain ultrasonography and two of them showed small hemorrhage-like lesion in magnetic resonance imaging. All depressed skull fractures improved within 6 months in followed X-rays or ultrasonography.
CONCLUSIONS: There was no definitely associated obstetric condition for depressed skull fracture of neonates although nulliparous women were majority of the affected cases.

BACKGROUND: Birth injury or birth trauma refers to physical damage or trauma that occurs to a newborn during the birthing process. To ensure continuous care and improve neonatal outcomes, it is crucial to know the incidence, types, relation to the mode of delivery, and their management.
METHODS: This is a retrospective cohort study conducted at Aga Khan University Hospital, Pakistan from January 2018 to December 2022. Neonates aged from birth to 28 days of life identified to sustain any form of mechanical birth injuries were included. Data analysis was done using SPSS version 19 (IBM Corp., Armonk, NY).
RESULTS: In the last five years, 51 mechanical birth injuries were found among 27,854 deliveries, which accounts for one in 546 births with an overall prevalence of 0.001%. Out of the total mechanical birth injuries, 12 (23.5%) were noticed in spontaneous vaginal delivery, six (11.8%) had instrumental delivery, and 33 (64.7%) patients had cesarean sections. More birth injuries were noticed in emergency cesarean section as compared to vaginal deliveries. There were 40 babies (78%) with soft tissue injuries, seven (14%) had musculoskeletal injuries/fractures, two (4%) babies had intracranial bleeding, and two (4%) had fractures along with intracranial bleeding. There was no mortality reported among these neonates.
CONCLUSIONS: The overall rate of birth injuries was significantly lower as compared to other low and middle-income countries. Most of the birth injuries were soft tissue injuries in patients with cesarean sections. The rate of birth injury did not show any association with the time of delivery. More frequent obstetric emergency drills would improve complications associated with shoulder dystocia.

BACKGROUND: Brachial plexus birth injury is the most common birth injury causing permanent disability in Finland. This study aimed to assess risk factors of a permanent brachial plexus birth injury and calculate the incidence.
METHODS: This is a retrospective population-based study including all deliveries between 2006 and 2022 in Southern Finland. The number of children born, obstetric data, and migrant status were gathered from the registries of the Finnish Institute for Health and Welfare, and Statistics Finland. Race of the mothers of children with a permanent brachial plexus birth injury was recorded. The severity of permanent brachial plexus birth injury was assessed using the 3-month Toronto test score. A lower score was indicative of a more severe injury (scored 0-10).
RESULTS: One hundred of the 298 428 children born during the 17-year study period sustained a permanent brachial plexus birth injury (0.34 per 1000). Mothers of children with a permanent brachial plexus birth injury had a higher body mass index (29 vs. 24 kg/m2) and their pregnancies were more often complicated by diabetes (28% vs. 12%), shoulder dystocia (58% vs. 0.3%), and/or assisted deliveries (45% vs. 10%) compared with all other mothers (p < 0.001). Thirty two of the 52 725 children born to migrant mothers had a permanent brachial plexus birth injury (0.61 per 1000). The incidence of permanent brachial plexus birth injury was 5.7 times higher among children of Black migrants from Africa (18/11 738, 1.53 per 1000) compared with children of native mothers (0.27 per 1000). Black mothers had a higher body mass index at the start of pregnancy (29 vs. 26 kg/m2, p = 0.02) compared with Caucasians. Children of Black mothers had a more severe injury compared with all others (p = 0.007) with a mean 3-month Toronto test score of 4.2 (range 0.0-6.5, SD ±1.6) vs. 5.6 (range 0.0-9.3, SD ±2.2).
CONCLUSIONS: Shoulder dystocia and assisted delivery are the most important risk factors for a permanent brachial plexus birth injury. Black race was associated with a higher rate and a more severe permanent brachial plexus birth injury.

The rare occurrence of Tarlov cysts in pediatric patients, particularly in the context of complex birth injuries, necessitates thorough evaluation and tailored management approaches. A comprehensive understanding of the clinical significance and optimal treatment strategies for this unique combination is crucial to ensure effective and individualized care for affected children.

Pelvic floor muscle injury is a common consequence of vaginal childbirth. Nonsteroidal anti-inflammatory drugs are widely used postpartum analgesics. Multiple studies have reported negative effects of these drugs on limb muscle regeneration, but their impact on pelvic floor muscle recovery following birth injury has not been explored.
Using a validated rat model, we assessed the effects of nonsteroidal anti-inflammatory drug on acute and longer-term pelvic floor muscle recovery following simulated birth injury.
Three-month old Sprague Dawley rats were randomly assigned to the following groups: (1) controls, (2) simulated birth injury, (3) simulated birth injury+nonsteroidal anti-inflammatory drug, or (4) nonsteroidal anti-inflammatory drug. Simulated birth injury was induced using a well-established vaginal balloon distension protocol. Ibuprofen was administered in drinking water (0.2 mg/mL), which was consumed by the animals ad libitum. Animals were euthanized at 1, 3, 5, 7, 10, and 28 days after birth injury/ibuprofen administration. The pubocaudalis portion of the rat levator ani, which, like the human pubococcygeus, undergoes greater parturition-associated strains, was harvested (N=3-9/time point/group). The cross-sectional areas of regenerating (embryonic myosin heavy chain+) and mature myofibers were assessed at the acute and 28-day time points, respectively. The intramuscular collagen content was assessed at the 28-day time point. Myogenesis was evaluated using anti-Pax7 and anti-myogenin antibodies to identify activated and differentiated muscle stem cells, respectively. The overall immune infiltrate was assessed using anti-CD45 antibody. Expression of genes coding for pro- and anti-inflammatory cytokines was assessed by quantitative reverse transcriptase polymerase chain reaction at 3, 5, and 10 days after injury.
The pubocaudalis fiber size was significantly smaller in the simulated birth injury+nonsteroidal anti-inflammatory drug compared with the simulated birth injury group at 28 days after injury (P<.0001). The median size of embryonic myosin heavy chain+ fibers was also significantly reduced, with the fiber area distribution enriched with smaller fibers in the simulated birth injury+nonsteroidal anti-inflammatory drug group relative to the simulated birth injury group at 3 days after injury (P<.0001), suggesting a delay in the onset of regeneration in the presence of nonsteroidal anti-inflammatory drugs. By 10 days after injury, the median embryonic myosin heavy chain+ fiber size in the simulated birth injury group decreased from 7 days after injury (P<.0001) with a tight cross-sectional area distribution, indicating nearing completion of this state of regeneration. However, in the simulated birth injury+nonsteroidal anti-inflammatory drug group, the size of embryonic myosin heavy chain+ fibers continued to increase (P<.0001) with expansion of the cross-sectional area distribution, signifying a delay in regeneration in these animals. Nonsteroidal anti-inflammatory drugs decreased the muscle stem cell pool at 7 days after injury (P<.0001) and delayed muscle stem cell differentiation, as indicated by persistently elevated number of myogenin+ cells 7 days after injury (P<.05). In contrast, a proportion of myogenin+ cells returned to baseline by 5 days after injury in the simulated birth injury group. The analysis of expression of genes coding for pro- and anti-inflammatory cytokines demonstrated only transient elevation of Tgfb1 in the simulated birth injury+nonsteroidal anti-inflammatory drug group at 5 but not at 10 days after injury. Consistently with previous studies, nonsteroidal anti-inflammatory drug administration following simulated birth injury resulted in increased deposition of intramuscular collagen relative to uninjured animals. There were no significant differences in any outcomes of interest between the nonsteroidal anti-inflammatory drug group and the unperturbed controls.
Nonsteroidal anti-inflammatory drugs negatively impacted pelvic floor muscle regeneration in a preclinical simulated birth injury model. This appears to be driven by the negative impact of these drugs on pelvic muscle stem cell function, resulting in delayed temporal progression of pelvic floor muscle regeneration following birth injury. These findings provide impetus to investigate the impact of postpartum nonsteroidal anti-inflammatory drug administration on muscle regeneration in women at high risk for pelvic floor muscle injury.

OBJECTIVE: To determine the association of successful and unsuccessful operative vaginal delivery attempts with risk of severe neonatal birth injury.
METHODS: We conducted a population-based observational study of 1 080 503 births between 2006 and 2019 in Quebec, Canada. The main exposure was operative vaginal delivery with forceps or vacuum, elective or emergency cesarean with or without an operative vaginal attempt, and spontaneous delivery. The outcome was severe birth injury, including intracranial hemorrhage, brain and spinal damage, Erb\'s paralysis and other brachial plexus injuries, epicranial subaponeurotic hemorrhage, skull and long bone fractures, and liver, spleen, and other neonatal body injuries. We determined the association of delivery mode with risk of severe birth injury using adjusted risk ratios (RR) and 95% confidence intervals (CI).
RESULTS: A total of 8194 infants (0.8%) had severe birth injuries. Compared with spontaneous delivery, vacuum (RR 2.98, 95% CI 2.80-3.16) and forceps (RR 3.35, 95% CI 3.07-3.66) were both associated with risk of severe injury. Forceps was associated with intracranial hemorrhage (RR 16.4, 95% CI 10.1-26.6) and brain and spinal damage (RR 13.5, 95% CI 5.72-32.0), while vacuum was associated with epicranial subaponeurotic hemorrhage (RR 27.5, 95% CI 20.8-36.4) and skull fractures (RR 2.04, 95% CI 1.86-2.25). Emergency cesarean after an unsuccessful operative attempt was associated with intracranial and epicranial subaponeurotic hemorrhage, but elective and other emergency cesareans were not associated with severe injury.
CONCLUSIONS: Operative vaginal delivery and unsuccessful operative attempts that result in an emergency cesarean are associated with elevated risks of severe birth injury.

The modified Mallet classification is widely used to measure motor function in brachial plexus birth injuries. The aim of the study was to investigate agreement and reliability of this classification under three different evaluation conditions: face-to-face; live tele-assessment; and delayed video-based assessment. A total of 100 children aged 4-15 years were included. Children were assessed by two raters except for live tele-assessment, which was performed by four raters. Agreement between the three different assessment conditions for the same rater were between strong and excellent for both raters 1 and 2. The interrater reliability for raters 1 and 2 under different assessment conditions was strong to excellent. Interrater reliability among the four raters was moderate to strong in tele-assessment. The modified Mallet classification may have appropriate reliability to be used in remote medical follow-up.Level of evidence: III.

This article describes the approach utilized by the multidisciplinary team at Sick Kids Hospital to evaluate and treat patients with brachial plexus birth injury (BPBI). This approach has been informed by more than 30 years of experience treating over 1,800 patients with BPBI and continues to evolve over time. The objective of this article is to provide readers with a practical overview of the Sick Kids approach to the management of infants with BPBI.