Birth weight and head circumference discordance and outcome in preterms: results from the EPIPAGE-2 cohort

OBJECTIVE

To determine whether the relative measurement of birth weight (BW) and head circumference (HC) in preterm infants is associated with neurological outcomes.

METHODS

The EPIPAGE-2 Study included 3473 infants born before 32 weeks' gestation, classified based on their Z-score of BW and HC on the Fenton curves as concordant (≤1 SD apart) or discordant (>1 SD difference). We defined four mutually exclusive categories: discordant smaller BW (sBW) with BW-1SD and concordant small measurement (CsM) with BW and HC concordant and both ≤-1SD. Neurological outcomes at 5.5 years were evaluated with standard tests.

RESULTS

2592 (74.8%) preterm neonates were categorised as CM, 258 (7.4%) CsM, 378 (10.9%) sHC and 239 (6.9%) sBW. Compared with the CM children, those born with CsM had significantly higher risks of cognitive deficiency (adjusted OR (aOR) 1.3, 95% CI (1.0 to 2.0)), developmental coordination disorders (aOR 2.6 (1.5 to 4.4)) and need for special school services (aOR 2.3 (1.5 to 3.7)). Those born with sBW had significantly lower risk of cognitive deficiency (aOR 0.6 (0.4 to 0.9)) and the sHC group significantly higher risk of developmental coordination disorders (aOR 1.8 (1.0 to 3.2)).

CONCLUSIONS

The relative discordance of these preterm infants' BW and HC was associated with their neurological outcomes. It merits further exploration as an indirect indicator of development.

TRIAL REGISTRATION NUMBER

NCT03078439.

Tocolysis after preterm prelabor rupture of membranes and 5-year outcomes: a population-based cohort study

BACKGROUND

The administration of tocolytics after preterm prelabor rupture of membranes remains a controversial practice. In theory, reducing uterine contractility should delay delivery and allow for optimal antenatal management, thereby reducing the risks for prematurity and adverse consequences over the life course. However, tocolysis may be associated with neonatal death or long-term adverse neurodevelopmental outcomes, mainly related to prolonged fetal exposure to intrauterine infection or inflammation. In a previous study, we showed that tocolysis administration was not associated with short-term benefits. There are currently no data available to evaluate the impact of tocolysis on neurodevelopmental outcomes in school-aged children born prematurely in this clinical setting.

OBJECTIVE

This study aimed to investigate whether tocolysis administered after preterm prelabor rupture of membranes is associated with neurodevelopmental outcomes at 5.5 years of age.

STUDY DESIGN

We used data from a prospective, population-based cohort study of preterm births recruited in 2011 (referred to as the EPIPAGE-2 study) and for whom the results of a comprehensive medical and neurodevelopmental assessment of the infant at age 5.5 years were available. We included pregnant individuals with preterm prelabor rupture of membranes at 24 to 32 weeks' gestation in singleton pregnancies with a live fetus at the time of rupture, birth at 24 to 34 weeks' gestation, and participation of the infant in an assessment at 5.5 years of age. Exposure was the administration of any tocolytic treatment after preterm prelabor rupture of membranes. The main outcome was survival without moderate to severe neurodevelopmental disabilities at 5.5 years of age. Secondary outcomes included survival without any neurodevelopmental disabilities, cerebral palsy, full-scale intelligence quotient, developmental coordination disorders, and behavioral difficulties. A propensity-score analysis was used to minimize the indication bias in the estimation of the treatment effect on outcomes.

RESULTS

Overall, 596 of 803 pregnant individuals (73.4%) received tocolytics after preterm prelabor rupture of membranes. At the 5.5-year follow-up, 82.7% and 82.5% of the children in the tocolysis and no tocolysis groups, respectively, were alive without moderate to severe neurodevelopmental disabilities; 52.7% and 51.1%, respectively, were alive without any neurodevelopmental disabilities. After applying multiple imputations and inverse probability of treatment weighting, we found no association between the exposure to tocolytics and survival without moderate to severe neurodevelopmental disabilities (odds ratio, 0.93; 95% confidence interval, 0.55-1.60), survival without any neurodevelopmental disabilities (odds ratio, 1.02; 95% confidence interval, 0.65-1.61), or any of the other outcomes.

CONCLUSION

There was no difference in the neurodevelopmental outcomes at age 5.5 years among children with and without antenatal exposure to tocolysis after preterm prelabor rupture of membranes. To date, the health benefits of tocolytics remain unproven, both in the short- and long-term.

Timing of antenatal corticosteroids and survival without neurologic disabilities at 5½ years in children born before 35 weeks of gestation

BACKGROUND

The efficacy of antenatal corticosteroids for neonatal preterm complications wanes beyond 7 days after treatment. The neurodevelopmental effects of longer treatment-to-birth intervals have not been adequately evaluated.

OBJECTIVE

This study aimed to assess the impact of antenatal corticosteroid timing on survival without moderate or severe neurologic disabilities at 5½ years.

STUDY DESIGN

This was a secondary analysis of the EPIPAGE-2 study, a national population-based cohort (France) that recruited neonates in 2011 and followed them up at 5½ years (results first reported in 2021). Participants were children born alive between 24+0 and 34+6 weeks, with a complete corticosteroid course, delivery >48 hours after the first injection, and neither limitation of care decided before birth nor severe congenital malformation. The study included 2613 children, 2427 of whom were alive at 5½ years; 71.9% (1739/2427) had a neurologic assessment at this age; 1537 had a clinical examination (complete for 1532), and 202 were assessed with a postal questionnaire. Exposure was defined as the interval between the first injection of the last antenatal corticosteroid course and delivery in days, studied in 2 categories (days 3-7 and after day 7), in 4 categories (days 3-7, 8-14, 15-21, and after day 21), and continuously in days. The main outcome was survival at 5½ years without moderate/severe neurologic disabilities, defined as moderate/severe cerebral palsy, or unilateral or bilateral blindness or deafness, or Full-Scale Intelligence Quotient 2 standard deviations below the mean. A multivariate analysis with a generalized estimated equation logistic regression model assessed the statistical association between the main outcomes and the interval from the first corticosteroid injection of the last course to birth. Multivariate analyses were adjusted for potential confounders, defined with a directed acyclic graph: gestational age in days, number of corticosteroid courses, multiple pregnancy, and cause of prematurity in 5 categories. Because neurologic follow-up was complete in only 63.2% of cases (1532/2427), the analyses used imputed data.

RESULTS

Among 2613 children, 186 died between birth and 5½ years. Overall survival was 96.6% (95% confidence interval, 95.9-97.0), and survival without moderate or severe neurologic disabilities was 86.0% (95% confidence interval, 84.7-87.0). Survival without moderate or severe neurologic disabilities was lower after day 7 (85.0%) than during the interval from day 3 to day 7 (87.0%) (adjusted odds ratio, 0.70; 95% confidence interval, 0.54-0.89).

CONCLUSION

The association of a >7-day interval between antenatal corticosteroid administration and birth with a lower rate of survival without moderate or severe neurologic disabilities among children aged 5½ years emphasizes the importance of better targeting women at risk of preterm delivery to optimize the timing and thus benefits of treatment.

[Intrahepatic cholestasis of pregnancy: French College of Obstetricians and Gynecologists guidelines for clinical practice]

OBJECTIVE

To identify strategies for reducing neonatal and maternal morbidity associated with intrahepatic cholestasis pregnancy (ICP).

MATERIAL AND METHODS

The quality of evidence of the literature was assessed following the GRADE methodology with questions formulated in the PICO format (Patients, Intervention, Comparison, Outcome) and outcomes defined a priori and classified according to their importance. An extensive bibliographic search was performed on PubMed, Cochrane, EMBASE and Google Scholar databases. The quality of the evidence was assessed (high, moderate, low, very low) and a (i) strong or (ii) weak recommendations or (iii) no recommendation were formulated. The recommendations were reviewed in two rounds with external reviewers (Delphi survey) to select the consensus recommendations.

RESULTS

Of the 14 questions (from 12 PICO questions and one definition question outside the PICO format), there was agreement between the working group and the external reviewers on 14 (100%). The level of evidence of the literature was insufficient to provide a recommendation on two questions. ICP is defined by the occurrence of suggestive pruritus (palmoplantar, nocturnal) associated with a total bile acid level>10μmol/L or an alanine transaminase level above 2N after ruling out differential diagnoses. In the absence of suggestive symptoms of a differential diagnosis, it is recommended not to carry out additional biological or ultrasound tests. In women with CIP, ursodeoxycholic acid is recommended to reduce the intensity of maternal pruritus (Strong recommendation. Quality of the evidence moderate) and to decrease the level of total bile acids and alanine transaminases. (Strong recommendation. Quality of the evidence moderate). S-adenosyl-methionine, dexamethasone, guar gum or activated charcoal should not be used to reduce the intensity of maternal pruritus (Strong recommendation. Quality of evidence low), and there is insufficient data to recommend the use of antihistamines (No recommendation. Quality of evidence low). Rifampicin (Weak recommendation. Very low quality of evidence) or plasma exchange (Strong recommendation. Very low quality of evidence) should not be used to reduce maternal pruritus and perinatal morbidity. Serum monitoring of bile acids is recommended to reduce perinatal morbidity and mortality (stillbirth, prematurity) (Low recommendation. Quality of the evidence low). The level of evidence is insufficient to determine whether fetal heart rate or fetal ultrasound monitoring are useful to reduce perinatal morbidity (No recommendation). Birth is recommended when bile acid level is above 99μmol/L from 36 weeks gestation to reduce perinatal morbidity, in particular stillbirth. When bile acid level is above 99μmol/L is below 100μmol/L, women should be informed that induction of labor could be considered 37 and 39 weeks gestation to reduce perinatal morbidity. (Strong recommendation. Quality of evidence low). In postpartum, total bile acids and alanine transaminases level should be checked and normalized before prescribing estrogen-progestin contraception, ideally with a low estrogen dose (risk of recurrence of pruritus and cytolysis) (Low recommendation. Quality of evidence very low).

CONCLUSION

Although the quality of evidence regarding ICP gestational cholestasis remains low, there is a strong consensus in France, as shown by our Delphi study, on how to manage women with ICP. The reference first-line treatment is ursodeoxycholic acid.

Risk of preterm delivery after medically indicated termination of pregnancy with induced vaginal delivery: a case-control study

We investigated whether nonsurgical termination of pregnancy after 14 weeks of gestation increases the risk of preterm delivery in a subsequent pregnancy. We conducted a two-centre retrospective case-control study. Patients who underwent non-surgical termination of pregnancy after 14 weeks of gestation between 2012 and 2015 and who gave birth after 14 weeks of gestation to a live-born singleton infant were included. Control patients were those who gave birth after 37 weeks of gestation (the same month as a case patient) and had a second delivery of a singleton foetus after 14 weeks of gestation. The primary outcome was preterm delivery during the second pregnancy period. We included 151 cases and 302 controls and observed 13 (8.6%) preterm births during the second pregnancy in the case group versus 8 (2.6%) (odds ratio: 3.62; 95% confidence interval: 1.40-8.65, p < .001) in the control group. This result remained significant after multivariate analysis. Impact statementWhat is already known about this topic? Many studies have evaluated the association between first-trimester surgical or non-surgical termination of pregnancy and the risk of preterm birth in the subsequent pregnancy. However, no study has evaluated the association between second- or third-trimester non-surgical termination of pregnancy due to foetal disease and the risk of preterm birth in the subsequent pregnancy. A small number of studies have included a small proportion of patients who previously underwent non-surgical termination of pregnancy after 14 weeks of gestation and later experienced first-trimester termination during their second pregnancy. These studies focussed on the impact of the interpregnancy interval or pharmacological induction of labour on the risk of preterm delivery in the subsequent pregnancy.What did the results of this study add? This is the first study to specifically evaluate the association between second- and third-trimester non-surgical terminations of pregnancy and the risk of preterm birth in the subsequent pregnancy. When compared with term birth, nonsurgical termination of pregnancy was associated with the risk of spontaneous preterm birth and hospitalisation in the neonatal intensive care unit in the subsequent pregnancy.What are the implications of these findings for clinical practice and further research? Further studies are required to confirm our results, but information delivered to patients with a late termination of pregnancy and during their pregnancy follow-up for the subsequent pregnancy could be modified to provide this information.

Preterm and term prelabour rupture of membranes: A review of timing and methods of labour induction

Prelabour rupture of membranes (PROM) exposes both foetuses and mothers to the risk of infection. Induction of labour has been proposed to reduce this risk, but its neonatal and maternal risks and benefits must be balanced against those of expectant management (EM). Recent randomized studies of preterm PROM show that EM until 37 weeks of gestation is associated with lower overall neonatal morbidity. In term PROM, active management is associated with a shorter birth interval but not with lower rates of neonatal infection. Similar maternal and neonatal outcomes are reported regardless of whether induction uses oxytocin, PGE2, or oral misoprostol.

Cause of preterm birth and late-onset sepsis in very preterm infants: the EPIPAGE-2 cohort study

BACKGROUND

The pathogenesis of late-onset sepsis (LOS) in preterm infants is poorly understood and knowledge about risk factors, especially prenatal risk factors, is limited. This study aimed to assess the association between the cause of preterm birth and LOS in very preterm infants.

METHODS

2052 very preterm singletons from a national population-based cohort study alive at 72 h of life were included. Survival without LOS was compared by cause of preterm birth using survival analysis and Cox regression models.

RESULTS

437 (20.1%) had at least one episode of LOS. The frequency of LOS varied by cause of preterm birth: 17.1% for infants born after preterm labor, 17.9% after preterm premature rupture of membranes, 20.3% after a placental abruption, 20.3% after isolated hypertensive disorders, 27.5% after hypertensive disorders with fetal growth restriction (FGR), and 29.4% after isolated FGR. In multivariate analysis, when compared to infants born after preterm labor, the risk remained higher for infants born after hypertensive disorders (hazard ratio HR = 1.7, 95% CI = 1.2-2.5), hypertensive disorders with FGR (HR = 2.6, 95% CI = 1.9-3.6) and isolated FGR (HR = 2.9, 95% CI = 1.9-4.4).

CONCLUSION

Very preterm infants born after hypertensive disorders or born after FGR had an increased risk of LOS compared to those born after preterm labor.

IMPACT

Late-onset sepsis risk differs according to the cause of preterm birth. Compared with those born after preterm labor, infants born very preterm because of hypertensive disorders of pregnancy and/or fetal growth restriction display an increased risk for late-onset sepsis. Antenatal factors, in particular the full spectrum of causes leading to preterm birth, should be taken into consideration to better prevent and manage neonatal infectious morbidity and inform the parents.

Impact of history of myomectomy on preterm birth risk in women with a leiomyomatous uterus: a propensity score analysis

BACKGROUND

To evaluate if women with a history of myomectomy have a modified preterm birth risk compared to women with myomas during pregnancy.

METHODS

Retrospective cohort study including all women with a history of myomectomy (operated group) or uterine myomas during pregnancy (unoperated group) who delivered in a tertiary center between January, 2011 and December, 2017. The operated group included women who had a myomectomy history with or without myomas during the ongoing pregnancy. The unoperated group included women with uterine myoma(s) seen on at least one ultrasound during pregnancy without history of myomectomy. The primary outcome was preterm birth < 37 weeks, and the secondary outcome spontaneous preterm birth < 37 weeks. To control for confounding factors, a propensity score approach was used. Two sensitivity analysis were performed, one repeating the analysis using the propensity score after excluding operated women with persistent myomas and one using a classical multivariable logistic regression model.

RESULTS

The cohort included 576 women: 283 operated women and 293 unoperated women. The rate of preterm birth was similar in the two groups: 12.6% in the unoperated group and 12.0% in the operated group (p = 0.82). No difference in preterm birth risk was shown between unoperated and operated women in the cohort matched on the propensity score: OR 0.86; 95%CI [0.47-1.59]. These results were consistent for spontaneous preterm birth (OR 1.61; 95%CI [0.61-4.23]) and for the sensitivity analyses.

CONCLUSION

In women with a leiomyomatous uterus, a history of myomectomy is not associated with a reduced preterm birth risk.

Neurodevelopment at 2 years and umbilical artery Doppler in cases of very preterm birth after prenatal hypertensive disorder or suspected fetal growth restriction: EPIPAGE-2 prospective population-based cohort study

OBJECTIVE

To investigate the association between absent or reversed end-diastolic flow (ARED) on umbilical artery Doppler ultrasound and poor neurological outcome at 2 years of age after very preterm birth associated with suspected fetal growth restriction (FGR) or maternal hypertensive disorders.

METHODS

The study population comprised all very preterm (22-31 completed weeks) singleton pregnancies delivered because of suspected FGR and/or maternal hypertensive disorders that had umbilical artery Doppler and 2-year follow-up available included in EPIPAGE-2, a prospective, nationwide, population-based cohort of preterm births in France in 2011. Univariate and two-level multivariable logistic regression analyses were used to assess the association of ARED in the umbilical artery, as compared with normal or reduced end-diastolic flow, with severe or moderate neuromotor and/or sensory disability and with an Ages and Stages Questionnaire (ASQ) score below a threshold. This was defined as a score more than 2 SD below the mean in any of the five domains, at age 2, adjusting for gestational age at delivery. ASQ is used to identify children at risk of developmental delay requiring reinforced follow-up and further evaluation. Descriptive statistics and bivariate tests were weighted according to the duration of the inclusion periods.

RESULTS

The analysis included 484 children followed up at 2 years of age, for whom prenatal umbilical artery Doppler ultrasound was available. Among them, 8/484 (1.6%) had severe or moderate neuromotor and/or sensory disability, and 156/342 (45.4%) had an ASQ score below the threshold. Compared with normal or reduced end-diastolic flow in the umbilical artery (n = 305), ARED (n = 179) was associated with severe or moderate neuromotor and/or sensory disability (adjusted odds ratio (OR), 11.3; 95% CI, 1.4-93.2) but not with an ASQ score below the threshold (adjusted OR, 1.2; 95% CI, 0.8-1.9).

CONCLUSION

Among children delivered before 32 weeks of gestation due to suspected FGR and/or maternal hypertensive disorder who survived until 2 years of age, prenatal ARED in the umbilical artery was associated with a higher incidence of severe or moderate neuromotor and/or sensory disability. Copyright © 2020 ISUOG. Published by John Wiley & Sons Ltd.

The cause of birth is associated with neonatal prognosis in late preterm singletons

INTRODUCTION

Recent studies have shown that the cause of very preterm births may be related to neonatal morbidity and mortality. Even though these risks are lower among late preterm births, this group accounts for the vast majority of all preterm births. The objective of this study was to evaluate the relation of neonatal morbidity and mortality to the cause of late preterm birth.

MATERIALS AND METHODS

This retrospective observational cohort study included all women who gave birth to liveborn singletons from 34 to 36 weeks+6 days of gestation in a French level III maternity hospital in the 5-year period 2013-2017. The causes of preterm delivery were divided into 6 mutually exclusive groups. The main outcome was a composite neonatal morbidity criterion, defined by at least one among the following criteria: neonatal respiratory distress, neurological complications, neonatal sepsis, severe necrotizing enterocolitis, and neonatal hypoglycemia. We analyzed the association between cause of preterm delivery and neonatal morbidity after adjustment for gestational age and antenatal corticosteroid therapy. The reference group was preterm labor, defined by spontaneous preterm labor with intact membranes.

RESULTS

During the study period, there were a total of 27 110 births, including 1114 singleton births at 34 to 36 weeks of gestation + 6 days (4.1%). Among the 968 late preterm births included, the risk of neonatal morbidity in the group with preterm premature rupture of membranes (PPROM) was similar to that in the preterm labor (reference) group: adjusted odds ratio (aOR) 1.2 (95% CI, 0.8-1.8). All the other causes of late preterm birth were associated with a higher risk of neonatal morbidity than the reference group: aOR 2.0 [95% CI, 1.1-3.5] for hypertensive disorders without suspected fetal growth restriction (FGR) (9.1% of cases), aOR 2.4 [95% CI, 1.4-4.2] for hypertensive disorders with suspected FGR (8.9%), aOR 4.2 [95% CI, 2.2-8.0] for suspected FGR without hypertensive disorders (5.8%), and aOR 4.4 [95% CI, 2.2-8.8] for vaginal bleeding related to abnormal placental insertion (4.7%).

CONCLUSION

Among infants born from 34 to 36 weeks + 6 days of gestation, PPROM and preterm labor had similar risks of neonatal morbidity, while the other causes were associated with a risk of neonatal morbidity at least twice that with preterm labor.

Carbetocin versus Oxytocin for the Prevention of Postpartum Hemorrhage in Cesarean Deliveries: A Retrospective Study of Two Consecutive Periods

Objective  The aim of the study is to investigate whether carbetocin prevents postpartum hemorrhage (PPH) more effectively than oxytocin Methods  This historical retrospective single-center cohort study compares women who underwent cesarean deliveries during two periods. During period A, oxytocin was used as a 10-unit bolus immediately after delivery, with 20 units thereafter infused for 24 hours. During period B, carbetocin in a single 100-µg injection replaced this protocol. The main outcome was PPH, defined as a decline in hemoglobin of more than 2 g/dL after the cesarean. The analysis was performed on the overall population and then stratified by the timing of the cesareans (before or during labor). A logistic regression analysis was performed. Results  This study included 1,796 women, 52% of whom had a cesarean before labor; 15% had a PPH. The crude PPH rate was lower in period B than in period A (13 vs. 17%, respectively, odds ratio 0.75, 95% confidence interval [CI]: 0.58-0.98). The difference was no longer significant in the multivariate analysis (adjusted odds ratio: 0.81, 95% CI 0.61-1.06). Results were similar when stratified by the timing of the cesareans (before or during labor). Conclusion  Carbetocin is not superior to oxytocin in preventing PPH. However, it does provide the advantage of requiring a single injection.

Association of Chorioamnionitis with Cerebral Palsy at Two Years after Spontaneous Very Preterm Birth: The EPIPAGE-2 Cohort Study

OBJECTIVE

To assess whether chorioamnionitis is associated with cerebral palsy (CP) or death at 2 years' corrected age in infants born before 32 weeks of gestation after spontaneous birth.

STUDY DESIGN

EPIPAGE-2 is a national, prospective, population-based cohort study of children born preterm in France in 2011; recruitment periods varied by gestational age. This analysis includes infants born alive after preterm labor or preterm premature rupture of membranes from 24^0/7 to 31^6/7 weeks of gestation. We compared the outcomes of CP, death at 2 years' corrected age, and "CP or death at age 2" according to the presence of either clinical chorioamnionitis or histologic chorioamnionitis. All percentages were weighted by the duration of the recruitment period.

RESULTS

Among 2252 infants born alive spontaneously before 32 weeks of gestation, 116 (5.2%) were exposed to clinical chorioamnionitis. Among 1470 with placental examination data available, 639 (43.5%) had histologic chorioamnionitis. In total, 346 infants died before 2 years and 1586 (83.2% of the survivors) were evaluated for CP at age 2 years. CP rates were 11.1% with and 5.0% without clinical chorioamnionitis (P = .03) and 6.1% with and 5.3% without histologic chorioamnionitis (P = .49). After adjustment for confounding factors, CP risk rose with clinical chorioamnionitis (aOR 2.13, 95% CI 1.12-4.05) but not histologic chorioamnionitis (aOR 1.21, 95% 0.75-1.93). Neither form was associated with the composite outcome "CP or death at age 2."

CONCLUSIONS

Among infants very preterm born spontaneously, the risk of CP at a corrected age of 2 years was associated with exposure to clinical chorioamnionitis but not histologic chorioamnionitis.

Evidence-based guidelines for the management of abnormally invasive placenta: recommendations from the International Society for Abnormally Invasive Placenta

The worldwide incidence of abnormally invasive placenta is rapidly rising, following the trend of increasing cesarean delivery. It is a heterogeneous condition and has a high maternal morbidity and mortality rate, presenting specific intrapartum challenges. Its rarity makes developing individual expertise difficult for the majority of clinicians. The International Society for Abnormally Invasive Placenta aims to improve clinicians' understanding and skills in managing this difficult condition. By pooling knowledge, experience, and expertise gained within a variety of different healthcare systems, the Society seeks to improve the outcomes for women with abnormally invasive placenta globally. The recommendations presented herewith were reached using a modified Delphi technique and are based on the best available evidence. The evidence base for each is presented using a formal grading system. The topics chosen address the most pertinent questions regarding intrapartum management of abnormally invasive placenta with respect to clinically relevant outcomes, including the following: definition of a center of excellence; requirement for antenatal hospitalization; antenatal optimization of hemoglobin; gestational age for delivery; antenatal corticosteroid administration; use of preoperative cystoscopy, ureteric stents, and prophylactic pelvic arterial balloon catheters; maternal position for surgery; type of skin incision; position of the uterine incision; use of interoperative ultrasound; prophylactic administration of oxytocin; optimal method for intraoperative diagnosis; use of expectant management; adjuvant therapies for expectant management; use of local surgical resection; type of hysterectomy; use of delayed hysterectomy; intraoperative measures to treat life-threatening hemorrhage; and fertility after conservative management.

Association between gestational age and severe maternal morbidity and mortality of preterm cesarean delivery: a population-based cohort study

BACKGROUND

Cesarean delivery rates at extreme prematurity have regularly increased over the past years, and few previous studies have investigated severe maternal morbidity associated with extreme preterm cesarean delivery.

OBJECTIVE

The aim of this study was to evaluate whether gestational age <26 weeks of gestation (weeks) was associated with severe maternal morbidity and mortality (SMMM) of preterm cesarean deliveries in comparison with cesarean deliveries between 26 and 34 weeks.

MATERIALS AND METHODS

The Etude Epidémiologique sur les petits âges gestationnels (EPIPAGE) 2 is a national prospective population-based cohort study of preterm births in 2011. We included mothers with cesarean deliveries between 22 and 34 weeks, excluding those who had a cesarean delivery for the second twin only and those with pregnancy terminations. SMMM was analyzed as a composite endpoint defined as the occurrence of at least 1 of the following complications: severe postpartum hemorrhage defined by the use of a blood transfusion, intensive care unit admission, or death. To assess the association of gestational age <26 weeks and SMMM, we used multivariate logistic regression and a propensity score-matching approach.

RESULTS

Among 2525 women having preterm cesarean deliveries, 116 before 26 weeks and 2409 between 26 and 34 weeks, 407 (14.4%) presented with SMMM. The SMMM occurred in 31 mothers (26.7%) who were at gestational age <26 weeks vs 376 (14.2%) between 26 and 34 weeks (P < .001). Cluster multivariate logistic regression showed significant association of gestational age <26 weeks and SMMM (adjusted odds ratio [aOR], 2.50; 95% confidence interval [CI], 1.42-4.40) and propensity score-matching analysis was consistent with these results (aOR, 2.27; 95% CI, 1.31-3.93).

CONCLUSION

Obstetricians should know about the higher SMMM associated with cesarean deliveries before 26 weeks, integrate this knowledge into decisions regarding cesarean delivery, and be prepared to manage the associated complications.

Preterm premature rupture of the membranes: Guidelines for clinical practice from the French College of Gynaecologists and Obstetricians (CNGOF)

In France, the frequency of premature rupture of the membranes (PROM) is 2%-3% before 37 weeks' gestation (level of evidence [LE] 2) and less than 1% before 34 weeks (LE2). Preterm delivery and intrauterine infection are the major complications of preterm PROM (PPROM) (LE2). Prolongation of the latency period is beneficial (LE2). Compared with other causes of preterm delivery, PPROM is associated with a clear excess risk of neonatal morbidity and mortality only in cases of intrauterine infection, which is linked to higher rates of in utero fetal death (LE3), early neonatal infection (LE2), and necrotizing enterocolitis (LE2). The diagnosis of PPROM is principally clinical (professional consensus). Tests to detect IGFBP-1 or PAMG-1 are recommended in cases of uncertainty (professional consensus). Hospitalization is recommended for women diagnosed with PPROM (professional consensus). Adequate evidence does not exist to support recommendations for or against initial tocolysis (Grade C). If tocolysis is prescribed, it should not continue longer than 48 h (Grade C). The administration of antenatal corticosteroids is recommended for fetuses with a gestational age less than 34 weeks (Grade A) and magnesium sulfate if delivery is imminent before 32 weeks (Grade A). The prescription of antibiotic prophylaxis at admission is recommended (Grade A) to reduce neonatal and maternal morbidity (LE1). Amoxicillin, third-generation cephalosporins, and erythromycin (professional consensus) can each be used individually or eythromycin and amoxicillin can be combined (professional consensus) for a period of 7 days (Grade C). Nonetheless, it is acceptable to stop antibiotic prophylaxis when the initial vaginal sample is negative (professional consensus). The following are not recommended for antibiotic prophylaxis: amoxicillin-clavulanic acid (professional consensus), aminoglycosides, glycopeptides, first- or second-generation cephalosporins, clindamycin, or metronidazole (professional consensus). Women who are clinically stable after at least 48 h of hospital monitoring can be managed at home (professional consensus). Monitoring should include checking for clinical and laboratory factors suggestive of intrauterine infection (professional consensus). No guidelines can be issued about the frequency of this monitoring (professional consensus). Adequate evidence does not exist to support a recommendation for or against the routine initiation of antibiotic therapy when the monitoring of an asymptomatic woman produces a single isolated positive result (e.g., elevated CRP, or hyperleukocytosis, or a positive vaginal sample) (professional consensus). In cases of intrauterine infection, the immediate intravenous administration (Grade B) of antibiotic therapy combining a beta-lactam with an aminoglycoside (Grade B) and early delivery of the child are both recommended (Grade A). Cesarean delivery of women with intrauterine infections is reserved for the standard obstetric indications (professional consensus). Expectant management is recommended for uncomplicated PROM before 37 weeks (Grade A), even when a sample is positive for Streptococcus B, as long as antibiotic prophylaxis begins at admission (professional consensus). Oxytocin and prostaglandins are two possible options for the induction of labor in women with PPROM (professional consensus).

[Preterm premature rupture of membranes: CNGOF Guidelines for clinical practice - Short version]

OBJECTIVE

To determine management of women with preterm premature rupture of membranes (PPROM).

METHODS

Bibliographic search from the Medline and Cochrane Library databases and review of international clinical practice guidelines.

RESULTS

In France, PPROM rate is 2 to 3% before 37 weeks of gestation (level of evidence [LE] 2) and less than 1% before 34 weeks of gestation (LE2). Prematurity and intra-uterine infection are the two major complications of PPROM (LE2). Compared to other causes of prematurity, PPROM is not associated with an increased risk of neonatal mortality and morbidity, except in case of intra-uterine infection, which is associated with an augmentation of early-onset neonatal sepsis (LE2) and of necrotizing enterocolitis (LE2). PPROM diagnosis is mainly clinical (professional consensus). In doubtful cases, detection of IGFBP-1 or PAMG-1 is recommended (professional consensus). Hospitalization of women with PPROM is recommended (professional consensus). There is no sufficient evidence to recommend or not recommend tocolysis (grade C). If a tocolysis should be prescribed, it should not last more than 48hours (grade C). Antenatal corticosteroids before 34 weeks of gestation (grade A) and magnesium sulfate before 32 weeks of gestation (grade A) are recommended. Antibiotic prophylaxis is recommended (grade A) because it is associated with a reduction of neonatal mortality and morbidity (LE1). Amoxicillin, 3rd generation cephalosporins, and erythromycin in monotherapy or the association erythromycin-amoxicillin can be used (professional consensus), for 7 days (grade C). However, in case of negative vaginal culture, early cessation of antibiotic prophylaxis might be acceptable (professional consensus). Co-amoxiclav, aminosides, glycopetides, first and second generation cephalosporins, clindamycin, and metronidazole are not recommended for antibiotic prophylaxis (professional consensus). Outpatient management of women with clinically stable PPROM after 48hours of hospitalization is a possible (professional consensus). During monitoring, it is recommended to identify the clinical and biological elements suggesting intra-uterine infection (professional consensus). However, it not possible to make recommendation regarding the frequency of this monitoring. In case of isolated elevated C-reactive protein, leukocytosis, or positive vaginal culture in an asymptomatic patient, it is not recommended to systematically prescribe antibiotics (professional consensus). In case of intra-uterine infection, it is recommended to immediately administer an antibiotic therapy associating beta-lactamine and aminoside (grade B), intravenously (grade B), and to deliver the baby (grade A). Cesarean delivery should be performed according to the usual obstetrical indications (professional consensus). Expectative management is recommended before 37 weeks of gestation in case of uncomplicated PPROM (grade A), even in case of positive vaginal culture for B Streptococcus, provided that an antibiotic prophylaxis has been prescribed (professional consensus). Oxytocin and prostaglandins are two possible options to induce labor in case of PPROM (professional consensus).

CONCLUSION

Expectative management is recommended before 37 weeks of gestation in case of uncomplicated PPROM (grade A).

Preterm premature rupture of membranes at 22-25 weeks' gestation: perinatal and 2-year outcomes within a national population-based study (EPIPAGE-2)

BACKGROUND

Most clinical guidelines state that with early preterm premature rupture of membranes, obstetric and pediatric teams must share a realistic and individualized appraisal of neonatal outcomes with parents and consider their wishes for all decisions. However, we currently lack reliable and relevant data, according to gestational age at rupture of membranes, to adequately counsel parents during pregnancy and to reflect on our policies of care at these extreme gestational ages.

OBJECTIVE

We sought to describe both perinatal and 2-year outcomes of preterm infants born after preterm premature rupture of membranes at 22-25 weeks' gestation.

STUDY DESIGN

EPIPAGE-2 is a French national prospective population-based cohort of preterm infants born in 546 maternity units in 2011. Inclusion criteria in this analysis were women diagnosed with preterm premature rupture of membranes at 22-25 weeks' gestation and singleton or twin gestations with fetus(es) alive at rupture of membranes. Latency duration, antenatal management, and outcomes (survival at discharge, survival at discharge without severe morbidity, and survival at 2 years' corrected age without cerebral palsy) were described and compared by gestational age at preterm premature rupture of membranes.

RESULTS

Among the 1435 women with a diagnosis of preterm premature rupture of membranes, 379 were at 22-25 weeks' gestation, with 427 fetuses (331 singletons and 96 twins). Median gestational age at preterm premature rupture of membranes and at birth were 24 (interquartile range 23-25) and 25 (24-27) weeks, respectively. For each gestational age at preterm premature rupture of membranes, nearly half of the fetuses were born within the week after the rupture of membranes. Among the 427 fetuses, 51.7% were survivors at discharge (14.1%, 39.5%, 66.8%, and 75.8% with preterm premature rupture of membranes at 22, 23, 24, and 25 weeks, respectively), 38.8% were survivors at discharge without severe morbidity, and 46.4% were survivors at 2 years without cerebral palsy, with wide variations by gestational age at preterm premature rupture of membranes. Survival at 2 years without cerebral palsy was low with preterm premature rupture of membranes at 22 and 23 weeks but reached approximately 60% and 70% with preterm premature rupture of membranes at 24 and 25 weeks.

CONCLUSION

Preterm premature rupture of membranes at 22-25 weeks is associated with high incidence of mortality and morbidity, with wide variations by gestational age at preterm premature rupture of membranes. However, a nonnegligible proportion of children survive without severe morbidity both at discharge and at 2 years' corrected age.

Placenta percreta is associated with more frequent severe maternal morbidity than placenta accreta

BACKGROUND

Abnormally invasive placentation is the leading cause of obstetric hysterectomy and can cause poor to disastrous maternal outcomes. Most previous studies of peripartum management and maternal morbidity have included variable proportions of severe and less severe cases.

OBJECTIVE

The aim of this study was to compare maternal morbidity from placenta percreta and accreta.

STUDY DESIGN

This retrospective study at a referral center in Paris includes all women with abnormally invasive placentation from 2003 through 2017. Placenta percreta and accreta were diagnosed histologically or clinically. When placenta percreta was suspected before birth, a conservative approach leaving the placenta in situ was proposed because of the intraoperative risk of cesarean delivery. When placenta accreta was suspected, parents were offered a choice of a conservative approach or an attempt to remove the placenta, to be followed in case of failure by hysterectomy. Maternal outcomes were compared between women with placenta percreta and those with placenta accreta/increta. The primary outcome measure was a composite criterion of severe acute maternal morbidity including at least 1 of the following: hysterectomy during cesarean delivery, delayed hysterectomy, transfusion of ≥10 U of packed red blood cells, septic shock, acute kidney injury, cardiovascular failure, maternal transfer to intensive care, or death.

RESULTS

Of the 156 women included, 51 had placenta percreta and 105 placenta accreta. Abnormally invasive placentation was suspected antenatally nearly 4 times more frequently in the percreta than the accreta group (96.1% [49/51] vs 25.7% [27/105], P < .01). Among the 76 women with antenatally suspected abnormally invasive placentation (48.7%), the rate of antenatal decisions for conservative management was higher in the percreta than the accreta group (100% [49/49] vs 40.7% [11/27], P < .01). The composite maternal morbidity rate was significantly higher in the percreta than the accreta group (86.3% [44/51] vs 28/105 [26.7%], P < .001). A secondary analysis restricted to women with an abnormally invasive placentation diameter >6 cm showed similar results (86.0% [43/50) vs 48.7% [19/38), P < .01). The rate of hysterectomy during cesareans was significantly higher in the percreta than the accreta group (52.9% [27/51] vs 20.9% [22/105], P < .01) as was the total hysterectomy rate (43/51 [84.3%] vs 23.8% [25/105], P < .01).

CONCLUSION

Severe maternal morbidity is much more frequent in women with placenta percreta than with placenta accreta, despite multidisciplinary planning, management in a referral center, and better antenatal suspicion.

Growth and shape of a laboratory alluvial fan

Using laboratory experiments, we investigate the influence of water and sediment discharges on the morphology of an alluvial fan. In our flume, a single-thread laminar river deposits corundum sand into a conical fan. We record the fan progradation with top-view images and measure its shape using the deformation of a Moiré pattern. The fan remains virtually self-affine as it grows, with a nearly constant slope. We find that, when the sediment discharge is small, the longitudinal slope of the fan remains close to that of a river at the threshold for sediment transport. Consequently the slope depends on the water discharge only. A higher sediment discharge causes the fan's slope to depart from the threshold value. Due to the downstream decrease of the sediment load, this slope gets shallower towards the fan's toe. This mechanism generates a concave fan profile. This suggests that we could infer the sediment flux that feeds a fan based on its proximal slope.

Intraoperative adverse events associated with extremely preterm cesarean deliveries

INTRODUCTION

At the same time as survival is increasing among premature babies born before 26 weeks of gestation, the rates of cesarean deliveries before 26 weeks is also rising. Our purpose was to compare the frequency of intraoperative adverse events during cesarean deliveries in two gestational age groups: 24-25 weeks and 26-27 weeks.

MATERIAL AND METHODS

This single-center retrospective cohort study included all women with cesarean deliveries performed before 28⁺⁰ weeks from 2007 through 2015. It compared the frequency of intraoperative adverse events between two groups: those at 24-25 weeks of gestation and at 26-27 weeks. Intraoperative adverse events were a classical incision, transplacental incision, difficulty in fetal extraction (explicitly mentioned in the surgical report), postpartum hemorrhage (≥500 mL of blood loss), and injury to internal organs. A composite outcome including at least one of these events enabled us to analyze the risk factors for intraoperative adverse events with univariate and multivariable analysis. Stratified analyses by the indication for the cesarean were performed.

RESULTS

We compared 74 cesarean deliveries at 24-25 weeks of gestation and 214 at 26-27 weeks. Intraoperative adverse events occurred at higher rates in the 24-25-week group (63.5 vs. 30.8%, p < 0.001). After adjustment for confounding factors, this group remained at significantly higher risk of intraoperative adverse events [adjusted odds ratio 5.04 (2.67-9.50)], even after stratification by indication for the cesarean.

CONCLUSION

These results should help obstetricians and women making decisions about cesarean deliveries at these extremely low gestational ages.

Impact of Latency Duration on the Prognosis of Preterm Infants after Preterm Premature Rupture of Membranes at 24 to 32 Weeks' Gestation: A National Population-Based Cohort Study

OBJECTIVE

To assess the impact of latency duration on survival, survival without severe morbidity, and early-onset sepsis in infants born after preterm premature rupture of membranes (PPROM) at 24-32 weeks' gestation.

STUDY DESIGN

This study was based on the prospective national population-based Etude Épidémiologique sur les Petits Ȃges Gestationnels 2 cohort of preterm births and included 702 singletons delivered in France after PPROM at 24-32 weeks' gestation. Latency duration was defined as the time from spontaneous rupture of membranes to delivery, divided into 4 periods (12 hours to 2 days [reference], 3-7 days, 8-14 days, and >14 days). Multivariable logistic regression was used to assess the relationship between latency duration and survival, survival without severe morbidity at discharge, or early-onset sepsis.

RESULTS

Latency duration ranged from 12 hours to 2 days (18%), 3-7 days (38%), 8-14 days (24%), and >14 days (20%). Rates of survival, survival without severe morbidity, and early-onset sepsis were 93.5% (95% CI 91.8-94.8), 85.4% (82.4-87.9), and 3.4% (2.0-5.7), respectively. A crude association found between prolonged latency duration and improved survival disappeared on adjusting for gestational age at birth (aOR 1.0 [reference], 1.6 [95% CI 0.8-3.2], 1.2 [0.5-2.9], and 1.0 [0.3-3.2] for latency durations from 12 hours to 2 days, 3-7 days, 8-14 days, and >14 days, respectively). Prolonged latency duration was not associated with survival without severe morbidity or early-onset sepsis.

CONCLUSION

For a given gestational age at birth, prolonged latency duration after PPROM does not worsen neonatal prognosis.

[Does post operative sonographic position of preventive cervical cerclage affect gestational age at birth?]

OBJECTIVE

To evaluate whether the position of preventive cerclage determined by immediate postoperative transvaginal cervical ultrasound is predictive of preterm birth.

METHODS

A single-center retrospective study conducted between 1 August 2007 and 31 December 2015 in a maternity type III who included women carrying out for a single pregnancy and who receive a McDonald preventive cerclage. Measurements of internal os-stitch, stitch-external os and the total length of the cervix were performed during immediate postoperative transvaginal cervical ultrasound. The position of the cerclage has been defined by the internal os-stitch/cervical length and stitch-external os/cervical length ratios. Measures were compared according to gestational age at delivery (before and after 32weeks and before and after 37weeks).

RESULTS

During the study period, 379 single pregnancies that received a McDonald preventive cerclage were included. The mean gestational age at delivery was 37.6±3.6 SA. The rate of preterm birth before 32weeks was 6.5% (n=25) and before 37weeks was 16.6% (n=63). There was no significant difference in the internal ost-stitch/cervical length ratios and the stitch-external ost/cervical length ratio between women who delivered before and after 32weeks or for those who delivered before and after 37weeks. The areas under the ROC curves for the various parameters studied were all less than or equal to 0.6.

CONCLUSIONS

The position of cerclage determined by transvaginal cervical ultrasound in immediate post operative does not seem predictive of the risk of premature birth.

Assessment of atropine-sufentanil-atracurium anaesthesia for endotracheal intubation: an observational study in very premature infants

Background

Premedication before neonatal intubation is heterogeneous and contentious. The combination of a short acting, rapid onset opioid with a muscle relaxant is considered suitable by many experts. The purpose of this study was to describe the tolerance and conditions of intubation following anaesthesia with atropine, sufentanil and atracurium in very premature infants.

Methods

Monocentric, prospective observational study in premature infants born before 32 weeks of gestational age, hospitalised in the NICU and requiring semi-urgent or elective intubation. Intubation conditions, heart rate, pulse oxymetry (SpO₂), arterial blood pressure and transcutaneous PCO₂ (TcPCO₂) were collected in real time during 30 minutes following the first drug injection. Repeated physiological measurements were analysed using mixed linear models.

Results

Thirty five intubations were performed in 24 infants with a median post conceptional age of 27.6 weeks and a median weight of 850 g at the time of intubation. The first attempt was successful in 74% and was similar for junior (75%) and senior (74%) operators. The operator rated conditions as “excellent” or “good” in 94% of intubations. A persistent increase in TcPCO₂ as compared to baseline was observed whereas other vital parameters showed no significant variations 5, 10, 15 and 30 minutes after the first drug injection. Eighteen (51%) desaturations (SpO2 less than or equal to 80% for more than 60 seconds) and 2 (6%) bradycardia (heart rate less than100 bpm for more than 60 seconds) were observed.

Conclusion

This drug combination offers satisfactory success rate for first attempt and intubation conditions for the operator without any significant change in heart rate and blood pressure for the patient. However it is associated with frequent desaturations and a possible persistent hypercapnia. SpO₂ and PCO₂ can be significantly modified during neonatal intubation and should be cautiously followed in this high-risk population.

Physiologically based pharmacokinetics and the dermal absorption of 2-butoxyethanol vapor by humans

It has generally been assumed that the skin contributes only minor amounts to the total uptake of solvent vapors, relative to the respiratory tract. Contrary to this assumption, the widely used glycol ether solvent, 2-butoxyethanol (BE), has been reported to be more effectively absorbed through the skin (75% of the total uptake) than through the lungs of humans (Johanson and Boman, 1991, Br. J. Ind. Med. 48, 788). The possibility that the finger prick blood sampling technique used in the Johanson and Boman study was confounded by locally high concentrations of BE at the site of absorption was suggested using a previously developed PBPK model (Corley et al., 1994, Toxicol. Appl. Pharmacol. 129, 61). The current study was conducted to verify the PBPK analysis and to determine whether or not the skin was the major site for absorption of BE vapor by exposing one arm from each of six human volunteers to 50 ppm 13C2-BE vapor for 2 hr. To evaluate the potential consequences of blood sampling techniques, samples were taken from both the unexposed arm (catheter; during and after exposure) and the exposed arm (finger prick; end of the exposure only) for analysis of both BE and its major metabolite, butoxyacetic acid (BAA). Butoxyacetic acid is responsible for the hemolysis observed in toxicity studies with laboratory animals. Humans, however, are significantly less sensitive to this effect. The concentration of BE in the finger prick blood samples averaged 1500 times higher than the corresponding concentration in venous blood sampled from a catheter installed in the unexposed arm at the end of the exposure. Blood BAA levels were generally within a factor of 4 of each other for the two techniques and, therefore, was considered a better indicator of systemic absorption. Urine was collected for 24 hr and analyzed for the following metabolites found in rat metabolism studies: free and conjugated BE, BAA, ethylene glycol (EG), and glycolic acid (GA), with only BAA detected in the human urine. More importantly, urinary BAA was found to be extensively conjugated ( approximately 67%) with glutamine, confirming recent reports. These results, coupled with PBPK modeling of worst-case exposure scenarios (no clothing, 100% of the body was exposed), demonstrated that no more than 15-27% (low-to-high relative temperatures and humidities), not 75%, of the total uptake of BE could be attributed to the skin of humans during simulated 8-hr exposures to the ACGIH TLV concentration of 25 ppm. Even less of the total uptake was attributed to the skin during simulations of exercise with whole-body exposures (5-9%) or by more realistic exposures of only the arms and head (1-8%). As a result, humans are unlikely to reach hemolytic concentrations of the metabolite BAA in blood following vapor exposures to BE.

A pilot course as a model for implementing a PBL curriculum

Many medical schools are shifting to a problem-based learning (PBL) curriculum, some without any transition period, others using periods of parallel-track curricula. The authors report on and discuss a third strategy for implementing PBL: using a pilot course as a model to facilitate the transition. After the Université de Montréal Faculty of Medicine chose to switch PBL, one course in the third year of the traditional curriculum was changed to PBL format 11 months before the new curriculum was to start in September 1993. This was done to develop local expertise, to gain confidence, to test the feasibility of the method, to produce a showcase, to assess more accurately the resources required, and to provide a practice ground for the curriculum planners and managers and the faculty-development training team. The authors discuss the planning of the pilot course, the training of the faculty in various aspects of PBL (writing problems, tutoring methods, etc.), the course implementation, and the course evaluation. Overall, the pilot course was well received by both the faculty and the students and provided much beneficial information that assisted the university in its transition to a new PBL curriculum.

Ultrastructural changes in the nerve fiber population of anastomosed vagal and spinal accessory nerves in the sheep

BACKGROUND

The ultrastructure of the vagal and spinal accessory nerves was studied 1) in normal sheep and 2) in sheep in which an experimental crossed-nerve anastomosis had been made by sectioning the supranodose vagal and spinal accessory nerves, then suturing the distal end of the vagal nerve to the distal end of the spinal accessory nerve, and allowing time for regeneration to occur. This study was carried out in order to analyze the modifications liable to occur when this technique is used and to specify the origin and the nature of the fibers that colonize the spinal accessory nerve.

METHODS

The study was performed in 4- to 5-month-old-sheep. After the surgical procedure, the animals were housed indoors during 1 year until their sacrifice by fixative perfusion. Then, nerve samples were dissected out, processed for electron microscopy, examined, and systematically photographed. After printing, the diameters of the nerve fibers were determined.

RESULTS

In sheep, the ratios of nonmyelinated to myelinated fibers (NF/MF) in the infranodose and supranodose vagal nerve and accessory spinal nerve were 1.21, 1.67, and 3.21, respectively. In both parts of the vagal nerve, the myelinated fibers had a unimodal diameter distribution around a peak of 4 microns; whereas, in the spinal accessory nerve, they were distributed bimodally, and 53% had values of 15-18 microns. After making the above anastomosis, the centrifugal vagal fibers degenerated, and the NF/MF ratios increased in the centripetal infranodose vagal nerve, in the reinnervating supranodose vagal nerve, and in the reinnervated spinal accessory nerve (approximately 1.87, 1.72, and 6.04, respectively). In all of these nerves, the myelinated fibers had a unimodal distribution with a peak at 4 microns, as in the vagal nerve of normal sheep.

CONCLUSIONS

These results reveal the large part taken by the nonmyelinated fibers in the nerve fiber population of the vagal nerve and support the vagal origin of the fibers reinnervating the spinal accessory nerve.

[Vagal sensory reinnervation and composition of the sterno-cephalic muscle in rabbits]

The crossed nerve anastomosis between the peripheral end of the vagus nerve, cut above the nodose ganglion, and the peripheral end of the accessory nerve has demonstrated the capacity of some vagal afferents to reinnervate, via the accessory nerve stump, certain sternocephalicus muscle fibers in the rabbit. These results add to our understanding of the capacity of these afferents to counter the past-denervational atrophying process that occurs in the reinnervated muscles and to evaluate the changes induced in these muscles during reinnervation. Our work shows that within 3 months, the vagal sensory reinnervation of previously denervated sternocephalicus muscles induces their total weight recovery. This recovery is concomitant on the one hand with the hypertrophy of the four muscle fiber types (I, IIBD, IIC and IIA) identified histochemically in the normal muscles and, on the other, with the appearance of small newly formed myofibers, which are often underlined by characteristic central nuclei. The vagal sensory neurones induce important changes in the percentages and the muscle cross-sectional distribution of the fibers in reinnervated muscles. In these muscles we see also the disappearance of the fast myosin heavy chains MHCIIB and MHCIID, the upholding of the fast MHCIIA percentage and an increase in the slow MHCI isoform.