HYPOXIA AND REPRODUCTIVE HEALTH: Hypoxia and labour.

Intermittent myometrial hypoxia is a normal feature of labour, as the powerful contractions compress blood vessels. In this review, we focus on the relation between hypoxia, myometrial metabolism, and contractility. We dissect how hypoxia can feedback and limit an ongoing contraction and help prevent foetal distress. The mechanisms involve acidification from lactate, decreased excitability, and a fall of intracellular calcium concentration. As this cycle of contraction and relaxation repeats in labour, the hypoxia also engenders mechanisms that increase force; hypoxia-induced force increase, HIFI. We also discuss the role of the myometrial blood vessels in dysfunctional labour, which is associated with lactic acidosis. In synthesising these studies, we have attempted to unify findings by considering the importance of experimental protocols and finding direct mechanistic evidence from human myometrium or in vivo studies. We have made suggestions for future studies to fill the holes in our understanding and speed up the translation of our knowledge to improve births for mothers and babies everywhere.

The behavior of dairy cattle in late gestation: Effects of parity and dystocia.

The aim of this study was to objectively assess, using an automated behavioral monitoring system, any behavioral differences between primiparous and multiparous cows before calving, and to quantify any behavioral differences between assisted (dystocic) and unassisted (eutocic) calvings. Data were collected from 32 multiparous and 12 primiparous Holstein dairy cattle to describe normal calving behavior and parity differences. To quantify behavior related to calving difficulty, the data from 14 animals that had dystocia at calving were matched to cows that had an eutocic calving based on parity, locomotion score, calf breed, calf sex, month, and year of calving. An IceQube (IceRobotics Ltd., South Queensferry, United Kingdom) was fitted to the right hind leg of cows 4 wk before their expected calving date. Data for lying time, standing time, number of steps, motion index (total motion), and the total number of standing and lying bouts (postural transitions) were automatically collected and summed into 15-min blocks. Behavioral variables were summarized into 2-h periods and 24-h periods before analyses. Mixed-effect models were used to analyze cow behavior in the last 4 d before calving (d -4 to -1), and on the day of calving. In the 4 d before calving, compared with multiparous cows, primiparous cows lay down an average 2.8 h/d less, had 9.1 more postural transitions/d (37.7 ± 1.2 vs. 27.6 ± 0.7), walked 172 more steps/d, and had a higher motion index (2,673.2 vs. 1,981.5 units/d). There was an effect of 2-h period on all behavioral variables on the day of calving. No indicator of calving difficulty was found on the day of calving, nor the days leading up to calving. These findings suggest that parity should be considered when predicting the day of calving, and changes in cow behavior on the day of calving could be used to identify calving cows, and to predict the time of calving.

Success of trial of labor in women with a history of previous cesarean section for failed labor induction or labor dystocia: a retrospective cohort study.

BACKGROUND: The rates of cesarean section (CS) are increasing worldwide leading to an increased risk for maternal and neonatal complications in the subsequent pregnancy and labor. Previous studies have demonstrated that successful trial of labor after cesarean (TOLAC) is associated with the least maternal morbidity, but the risks of unsuccessful TOLAC exceed the risks of scheduled repeat CS. However, prediction of successful TOLAC is difficult, and only limited data on TOLAC in women with previous failed labor induction or labor dystocia exists. Our aim was to evaluate the success of TOLAC in women with a history of failed labor induction or labor dystocia, to compare the delivery outcomes according to stage of labor at time of previous CS, and to assess the risk factors for recurrent failed labor induction or labor dystocia. METHODS: This retrospective cohort study of 660 women with a prior CS for failed labor induction or labor dystocia undergoing TOLAC was carried out in Helsinki University Hospital, Finland, between 2013 and 2015. Data on the study population was obtained from the hospital database and analyzed using SPSS. RESULTS: The rate of vaginal delivery was 72.9% and the rate of repeat CS for failed induction or labor dystocia was 17.7%. The rate of successful TOLAC was 75.6% in women with a history of labor arrest in the first stage of labor, 73.1% in women with a history of labor arrest in the second stage of labor, and 59.0% in women with previous failed induction. The adjusted risk factors for recurrent failed induction or labor dystocia were maternal height < 160 cm (OR 1.9 95% CI 1.1-3.1), no prior vaginal delivery (OR 8.3 95% CI 3.5-19.8), type 1 or gestational diabetes (OR 1.8 95% CI 1.0-3.0), IOL for suspected non-diabetic fetal macrosomia (OR 10.8 95% CI 2.1-55.9) and birthweight ≥4500 g (OR 3.3 95% CI 1.3-7.9). CONCLUSIONS: TOLAC is a feasible option to scheduled repeat CS in women with a history of failed induction or labor dystocia. However, women with no previous vaginal delivery, maternal height < 160 cm, diabetes or suspected neonatal macrosomia (≥4500 g) may be at increased risk for failed TOLAC.

Influence of denaverine hydrochloride on calving ease in Holstein-Friesian heifers.

Calving is assumed to be an exhausting and painful event. A drug that eases the calving procedure and alleviates pain would help cows, especially those suffering from dystocia. In a randomized, controlled, and blinded trial, we measured the effect of denaverine hydrochloride on physical and physiological calving parameters. Eighty-three Holstein-Friesian heifers were included in the analysis. Pulling force was measured using a digital force gauge interposed between the calf and a mechanical calf puller. The concentration of cortisol was measured in serum before and after parturition. There was no effect of treatment group on calving modality (i.e., spontaneous vs. assisted calving), duration of calving, and cortisol concentration. The area under the curve of pulling force × time (n = 44), however, was significantly smaller in the treatment group compared with the placebo group. Also, duration of calving assistance was numerically shorter in the treatment group compared with the placebo group. The results provide evidence that calving ease can be influenced by denaverine hydrochloride during calving assistance.

Evaluating Fundal Dominant Contractions on Spatiotemporal Electrohysterography as a Marker for Effective Labor Contractions.

OBJECTIVE: To evaluate if fundal (F) dominance of the electrohysterogram is associated with vaginal delivery and lack of F dominance is associated with cesarean for labor dystocia. STUDY DESIGN: We conducted a prospective cohort study of nulliparous women in spontaneous labor at ≥36 weeks. Clinicians were blinded to electrohysterography data which were in addition to standard cardiotocography. All contractions in the hour preceding diagnosis of complete cervical dilation (for women delivering vaginally) or the hour preceding the decision for cesarean were analyzed. RESULTS: Of 224 patients, 167 had evaluable data. The proportion of F dominant contractions was not different for women undergoing cesarean for labor dystocia (n = 11) compared with all others (n = 156)-88.7 ± 10.2 versus 86.0 ± 11.4%; p = 0.44. Results were similar when comparing the cesarean for labor dystocia group to those undergoing cesarean for other indications (n = 10) and vaginal deliveries (n = 146)-88.7 ± 10.2 versus 86.5 ± 10.0 versus 85.9 ± 11.5%; p = 0.74. CONCLUSION: We were unable to confirm our earlier finding that F dominance of the electrohysterogram is associated with vaginal delivery and lack of F dominance is associated with cesarean for dystocia.

A functional role for AMPK in female fertility and endometrial regeneration.

Adenosine monophosphate-activated protein kinase (AMPK) is a highly conserved heterotrimeric complex that acts as an intracellular energy sensor. Based on recent observations of AMPK expression in all structures of the female reproductive system, we hypothesized that AMPK is functionally required for maintaining fertility in the female. This hypothesis was tested by conditionally ablating the two catalytic alpha subunits of AMPK, Prkaa1 and Prkaa2, using Pgr-cre mice. After confirming the presence of PRKAA1, PRKAA2 and the active phospho-PRKAA1/2 in the gravid uterus by immunohistochemistry, control (Prkaa1/2 fl/fl ) and double conditional knockout mice (Prkaa1/2 d/d ) were placed into a six-month breeding trial. While the first litter size was comparable between Prkaa1/2 fl/fl and Prkaa1/2 d/d female mice (P = 0.8619), the size of all subsequent litters was dramatically reduced in Prkaa1/2 d/d female mice (P = 0.0015). All Prkaa1/2 d/d female mice experienced premature reproductive senescence or dystocia by the fourth parity. This phenotype manifested despite no difference in estrous cycle length, ovarian histology in young and old nulliparous or multiparous animals, mid-gestation serum progesterone levels or uterine expression of Esr1 or Pgr between Prkaa1/2 fl/fl and Prkaa1/2 d/d female mice suggesting that the hypothalamic-pituitary-ovary axis remained unaffected by PRKAA1/2 deficiency. However, an evaluation of uterine histology from multiparous animals identified extensive endometrial fibrosis and disorganized stromal-glandular architecture indicative of endometritis, a condition that causes subfertility or infertility in most mammals. Interestingly, Prkaa1/2 d/d female mice failed to undergo artificial decidualization. Collectively, these findings suggest that AMPK plays an essential role in endometrial regeneration following parturition and tissue remodeling that accompanies decidualization.

A Holstein-Friesian dairy farm survey of postparturient factors influencing the days to first AI and days open in Hungary.

The authors monitored the postpartum period during the first seven weeks after calving at a Holstein-Friesian dairy farm in Hungary. Calvings occurred between 2013 and 2015 in three periods from June to November each year (n = 314). Data were collected from the farm record and ultrasonographic examinations were performed between 22 to 28 and 43 to 49 days in milk (DIM), respectively. The animals were followed until successful artificial insemination (AI), i.e. until becoming pregnant or until culling, but at most at 365 DIM. The prevalence of dystocia, twin calving, stillbirth rate and retained fetal membranes (RFM) was 23.2%, 3.8%, 3.5%, and 34.4%, respectively. Altogether 38.9% of the cows (n = 122) had bacterial complications of involution in the first 49 DIM. The prevalence of Grade 2 clinical (puerperal) metritis (CM) was 20.1% within 5 DIM, 10.5% between 6 to 10 DIM and 13.1% from 11 to 20 DIM, while 9.9% of the cows had clinical endometritis (CEM) between 21 and 28 DIM and 1.3% of the cows between 42 and 49 DIM, respectively. Pyometra was diagnosed in 1% of the cows between 21 and 28 DIM and 0.3% between 42 to 49 DIM, respectively. About 80% (80.6%) of the cows were inseminated at least once (n = 253). The success rate of the first AI was 26.9% (n = 68). Dystocia, twin calving, RFM, CM, CEM and cyclicity had no significant effect on the days between calving and first AI, however, according to the Kaplan-Meier analysis stillbirth significantly increased the number of days from calving to first AI (P = 0.039). According to the Kaplan- Meier analysis dystocia, twin calving, stillbirth, RFM, and cyclicity had no effect on the days open. In cows with CM developed within 5 DIM or with CEM diagnosed between 21 and 28 DIM the number of days open significantly decreased (P = 0.009 and P = 0.007, respectively), which confirms the importance of early diagnosis and treatment of uterine diseases. Similar surveys should be conducted to discover the risk factors for reproductive diseases in order to decrease the reproductive losses in dairy farms.

Cervical dilation at time of caesarean delivery in nulliparous women: a population-based cohort study.

OBJECTIVES: Our objective was to describe contemporary practice patterns in the timing of caesarean delivery in relation to cervical dilation, overall and by indication for caesarean. Our secondary objective was to examine how commonly caesarean delivery was performed for labour dystocia at dilations below 4 cm or without the use of oxytocin, overall and between hospitals. DESIGN: Retrospective, population-based cohort study. SETTING: Ontario, Alberta, and British Columbia, Canada, 2008-2012. POPULATION: Nulliparous women in labour who delivered term singletons in cephalic position. METHODS: Histograms were used to examine the distribution of cervical dilation at time of caesarean delivery, overall and by indication for caesarean. Funnel plots were used to illustrate variation in hospital-level rates of caesarean deliveries for labour dystocia that were performed early (<4 cm dilation) or without the use of oxytocin. MAIN OUTCOME MEASURES: Cervical dilation (in centimetres) at time of caesarean delivery. RESULTS: The population-based cohort comprised 392 025 women, of whom 18.8% had a caesarean delivery. Of first-stage caesareans for labour dystocia in women who entered labour spontaneously, 13.6% (95% CI 12.9, 14.2) had dilations <4 cm [hospital-level inter-quartile range (IQR): 6.2% to 20.0%] and 29.5% (95% CI 28.6, 30.4) did not receive oxytocin to treat their dystocia (hospital-level IQR: 22.1-54.6%). CONCLUSIONS: The proportion of caesareans done before 4 cm dilation or without oxytocin varies substantially across hospitals and suggests the need for institutions to review their practices and ensure that management of labour practice guidelines are followed. TWEETABLE ABSTRACT: Many caesareans for labour dystocia are performed early during labour (<4 cm dilation) or without oxytocin.

A comparison of 4 predictive models of calving assistance and difficulty in dairy heifers and cows.

The aim of this study was to build and compare predictive models of calving difficulty in dairy heifers and cows for the purpose of decision support and simulation modeling. Models to predict 3 levels of calving difficulty (unassisted, slight assistance, and considerable or veterinary assistance) were created using 4 machine learning techniques: multinomial regression, decision trees, random forests, and neural networks. The data used were sourced from 2,076 calving records in 10 Irish dairy herds. In total, 19.9 and 5.9% of calving events required slight assistance and considerable or veterinary assistance, respectively. Variables related to parity, genetics, BCS, breed, previous calving, and reproductive events and the calf were included in the analysis. Based on a stepwise regression modeling process, the variables included in the models were the dam's direct and maternal calving difficulty predicted transmitting abilities (PTA), BCS at calving, parity; calving assistance or difficulty at the previous calving; proportion of Holstein breed; sire breed; sire direct calving difficulty PTA; twinning; and 2-way interactions between calving BCS and previous calving difficulty and the direct calving difficulty PTA of dam and sire. The models were built using bootstrapping procedures on 70% of the data set. The held-back 30% of the data was used to evaluate the predictive performance of the models in terms of discrimination and calibration. The decision tree and random forest models omitted the effect of twinning and included only subsets of sire breeds. Only multinomial regression and neural networks explicitly included the modeled interactions. Calving BCS, calving difficulty PTA, and previous calving assistance ranked as highly important variables for all 4 models. The area under the receiver operating characteristic curve (ranging from 0.64 to 0.79) indicates that all of the models had good overall discriminatory power. The neural network and multinomial regression models performed best, correctly classifying 75% of calving cases and showing superior calibration, with an average error in predicted probability of 3.7 and 4.5%, respectively. The neural network and multinomial regression models developed are both suitable for use in decision-support and simulation modeling.

Factors leading to cesarean section delivery at Felegehiwot referral hospital, Northwest Ethiopia: a retrospective record review.

BACKGROUND: Cesarean section is the commonest obstetric operative procedure worldwide. When used appropriately cesarean sections can improve infant and/or maternal outcomes. However, when used inappropriately the potential harm may exceed the potential benefit of cesarean section. Appreciating the limited information in this area the current study assessed the rate and factors associated with cesarean section in Felegehiwot referral hospital, Bahir Dar, northwest Ethiopia. METHOD: The study was a retrospective analysis of eligible patient records that included 2967 pregnant women who had underwent either cesarean or vaginal delivery from July 1, 2012 to June 31, 2013. The data were double entered to EPI-INFO 3.5.2 and analyzed with SPSS. Binary logistic regression model was fitted to identify independent factors associated with cesarean section. RESULT: The proportion of women who underwent cesarean section in this study was 25.4%. Obstructed labor (30.7%), fetal distress (15.9%) and abnormal presentation (13.4%) were the major obstetric indications for cesarean section. The odd of undergoing cesarean section was higher among mothers in rural residence (AOR = 1.63, 95% CI: 1.21, 2.20), mothers reported to have pregnancy risk factors (AOR = 2.31, 95% CI: 1.74, 3.07) and lower among mothers in age category of 15-19 (AOR = 0.63, 95% CI: 0.43, 0.93). CONCLUSION: Obstetric factors occurring around birth, including obstructed labor and fetal distress were the main reasons leading to Cesarean Section rather than background characteristics assumed to be a risk. The results imply that there is a need for timely and accurate screening of women during obstetric care and, decision to perform cesarean section should be based on clear, compelling and well-supported justifications.

Elevated amniotic fluid lactate predicts labor disorders and cesarean delivery in nulliparous women at term.

OBJECTIVE: We sought to assess amniotic fluid lactate (AFL) at diagnosis of spontaneous labor at term (≥37 weeks) as a predictor of labor disorders (dystocia) and cesarean delivery (CD). STUDY DESIGN: This was a single-institution, prospective cohort study of 905 singleton, cephalic, term (≥37 weeks) nulliparous women in spontaneous labor. A standard management of labor (active management of labor) including a standard oxytocin regimen up to a maximum dose of 30 mU/min was applied. AFL was measured using a point-of-care device (LMU061; ObsteCare, Stockholm, Sweden). Labor arrest in the first stage of labor was defined as the need for oxytocin when cervical dilatation was <1 cm/h over 2 hours and in the second stage of labor by poor descent and rotation over 1 hour. Standard statistical analysis included analysis of variance, Pearson correlations, and binary logistic regression. Unsupervised decision tree analysis with 10-fold cross-validation was used to identify AFL thresholds. RESULTS: AFL was normally distributed and did not correlate with age, body mass index, or gestation. Unsupervised decision tree analysis demonstrated that AFL could be divided into 3 groups: 0-4.9 mmol/L (n = 118), 5.0-9.9 mmol/L (n = 707), and ≥10.0 mmol/L (n = 80). Increasing AFL was associated with higher total oxytocin dose (P = .001), labor disorders (P = .005), and CD (P ≤ .001). Multivariable regression analysis demonstrated that women with AFL ≥5.0-9.9 mmol/L (odds ratio [OR], 1.6; 95% confidence interval [CI], 1.06-2.39) and AFL ≥10.0 mmol/L (OR, 1.72; 95% CI, 1.01-2.93) were independent predictors of a labor disorder. AFL ≥5.0-9.9 mmol/L did not predict CD but multivariable analysis confirmed that AFL ≥10.0 mmol/L was an independent predictor of CD (OR, 3.35; 95% CI, 1.73-6.46). AFL ≥5.0-9.9 mmol/L had a sensitivity of 89% in predicting a labor disorder and a sensitivity of 93% in predicting CD with a 97% negative predictive value. AFL ≥10.0 mmol/L was highly specific but lacked sensitivity for CD. There was no difference in birthweight of infants according to labor disorder and delivery method. CONCLUSION: AFL at diagnosis of labor in spontaneously laboring single cephalic nulliparous term women is an independent predictor of a labor disorder and CD. These data suggest that women with AFL between 5.0-9.9 mmol/L with a labor disorder may be amenable to correction using the active management of labor protocol.

Management of the first stage of labor: potential strategies to lower the cesarean delivery rate.

To review management strategies associated with lower risk for cesarean delivery. Targeted literature review for labor interventions during the first stage of labor. There is evidence that policies regarding labor admission criteria, standardized policies regarding labor management including judicious use of oxytocin, standardized terminology and treatment for electronic fetal monitoring, standardized criteria for dystocia, and systematic implementation of policies that incorporate continuous supportive care during labor are associated with lower risk for cesarean. Evidence regarding use of amniotomy is conflicting. Management of the first stage of labor can affect the risk for cesarean delivery.

Preventing primary cesarean births: midwifery care.

The incidence of cesarean birth in the United States is alarmingly high and cesareans are associated with added morbidities for women and newborns. Thus strategies to prevent cesarean particularly for low-risk, nulliparous women at term with a singleton fetus are needed. This article addresses evidence-based practices that may be used during intrapartum to avoid primary cesarean, including patience with progress in labor, intermittent auscultation, continuous labor support, upright positions, and free mobility. Second-stage labor practices, such delayed pushing and manual rotation of the fetus, are also reviewed. This package of midwifery-style care practices can potentially lower primary cesarean rates.

A randomized controlled trial on early induction compared to expectant management of nulliparous women with prolonged latent phases.

OBJECTIVE: To compare early induction and expectant management regarding delivery outcomes and the experience of delivery in nulliparous women with prolonged latent phases. DESIGN: Randomized controlled trial. SETTING: One delivery unit in a Swedish hospital. POPULATION: Nulliparous women at term experiencing continuous contractions impeding rest (women's report) and exceeding 18 h, a cervical dilation of less than 4 cm, intact membranes and with a singleton fetus in cephalic presentation. METHODS: The women were randomly allocated to either early induction (n = 65) or expectant management (n = 64). All participants received medication for therapeutic rest. The early induction group was induced five hours after medication, and the expectant group awaited spontaneous onset of labor. The Wijma Delivery Experience Questionnaire (W-DEQ version B) was filled in after delivery. MAIN OUTCOME MEASURES: The primary outcome was mode of delivery. Secondary outcomes included birth experience, duration of labor, postpartum hemorrhage, and neonatal outcomes. RESULTS: The cesarean section rate was 15 of 65 (23.1%) in the early induction group and 24 of 64 (37.5%) in the expectant group (p = 0.076, OR 2.00, 95% CI 0.93-4.31). No significant differences were shown regarding delivery, neonatal outcomes or birth experience. CONCLUSIONS: No significant differences were shown between the two groups in the rate of cesarean sections or the experience of delivery. According to the actual results, the power to detect a difference was only 45%. The cesarean section rate was high in both groups, regardless of intervention.

Normal first stage of preterm labor.

OBJECTIVE: To compare first-stage labor patterns in women in preterm labor to those in labor at term. STUDY DESIGN: We performed a retrospective cohort study of consecutive women admitted from 2004 to 2008 with viable (≥ 24 weeks) vertex singleton gestations who reached the second stage of labor. Labor curves for preterm and term labor were created using a repeated-measures analysis with polynomial modeling. Interval-censored regression was used to estimate and compare median time of progression of labor. Multivariable analyses were performed to adjust for smoking, obesity (body mass index ≥ 30), induction, and nulliparity. The adjusted model was stratified by parity and induction of labor. RESULTS: Of 5,612 consecutive births, 224 were preterm (<37 weeks) and 5,388 were term (≥ 37 weeks). Preterm first-stage labor progressed significantly faster than term labor (median time 4 to 10 cm: 3.3 hours versus 4.5 hours, p < 0.01). When stratified by parity, preterm labor progressed significantly more rapidly than term labor in both nulliparous and multiparous women (median time 4 to 10 cm: 3.7 hours versus 4.9 hours [p = 0.04] in nulliparous women and 2.5 hours versus 4.3 hours [p = 0.01] in multiparous women). CONCLUSION: Women in preterm labor progress more rapidly through the first stage of labor than women at term.

Too tight to give birth? Assessment of pelvic floor muscle function in 277 nulliparous pregnant women.

INTRODUCTION AND HYPOTHESIS: Theoretically, tight or strong pelvic floor muscles may impair the progress of labor and lead to instrumental deliveries. We aimed to investigate whether vaginal resting pressure, pelvic floor muscle strength, or endurance at midpregnancy affect delivery outcome. METHODS: This was a prospective cohort study of women giving birth at a university hospital. Vaginal resting pressure, pelvic floor muscle strength, and endurance in 300 nulliparous pregnant women were assessed at mean gestational week 20.8 (±1.4) using a high precision pressure transducer connected to a vaginal balloon. Delivery outcome measures [acute cesarean section, prolonged second stage of labor (> 2 h), instrumental vaginal delivery (vacuum and forceps), episiotomy, and third- and fourth-degree perineal tear) were retrieved from the hospital's electronic birth records. RESULTS: Twenty-three women were lost to follow-up, mostly because they gave birth at another hospital. Women with prolonged second stage had significantly higher resting pressure than women with second stage less than 2 h; the mean difference was 4.4 cmH2O [95 %confidence interval (CI) 1.2-7.6], p < 0.01, adjusted odds ratio 1.049 (95 % CI 1.011-1.089, p = 0.012). Vaginal resting pressure did not affect other delivery outcomes. Pelvic floor muscle strength and endurance similarly were not associated with any delivery outcomes. CONCLUSIONS: While midpregnancy vaginal resting pressure is associated with prolonged second stage of labor, neither vaginal resting pressure nor pelvic floor muscle strength or endurance are associated with operative delivery or perineal tears. Strong pelvic floor muscles are not disadvantageous for vaginal delivery.

Cervical dilation at the time of cesarean section for dystocia -- effect on subsequent trial of labor.

OBJECTIVE: To investigate the effect of cervical dilation at the time of cesarean section due to dystocia and success in a subsequent pregnancy of attempted vaginal delivery. DESIGN: Retrospective study. SETTING: University hospital in Copenhagen capital area. POPULATION: All women with a prior cesarean section due to dystocia who had undergone a subsequent pregnancy with a singleton delivery during 2006-2010. METHODS: Medical records were reviewed for prior vaginal birth, cervical dilation reached before cesarean section and induction of labor, gestational age, use of oxytocin, epidural anesthesia and mode of birth was collected. RESULTS: A total of 889 women were included; 373 had had a trial of labor. The success rate for vaginal birth among women with prior cesarean section for dystocia at 4-8 cm dilation was 39%, but 59% for women in whom prior cesarean section had been done at a fully or almost fully dilated cervix (9-10 cm) (p < 0.001). Among the women with a previous vaginal delivery prior to their cesarean section, the success rate for vaginal birth was 76.2%, in contrast to 48.9% in the group without a previous vaginal delivery (p < 0.01). CONCLUSION: Women who had a trial of labor after a prior cesarean section for dystocia done late in labor and women with a vaginal delivery prior to their cesarean section had a greater chance of a successful vaginal birth during a subsequent delivery.

Association between dry period length and lactation performance, lactation curve, calf birth weight, and dystocia in Holstein dairy cows in Iran.

In this study, 65,971 lactations on 41,842 cows in 64 herds were used to determine the association between dry period length (DPL) and lactation performance, lactation curve, calf birth weight, and the incidence of calving difficulty during the subsequent parity in Holstein dairy cows in Iran. The length of the dry period was classified into 7 categories: 0 to 35d, 36 to 50d, 51 to 60d, 61 to 70d, 71 to 85d, 86 to 110d, and 111 to 160d. Cows with the standard DPL (51 to 60d) produced more 305-d milk, fat, and protein over the next lactation compared with those with shorter dry periods. Shorter dry periods (0 to 35d and 36 to 50d) were associated with lower initial milk yield, steeper inclining and declining slopes of the lactation curve, and higher milk persistency compared with dry period length of 51 to 60d. Peak lactation was achieved later in cows with 0- to 35-d and 36- to 50-d dry period length than in those with dry period length of 51 to 60d. We also observed a relationship between DPL and calf birth weight: smaller calf birth weight was recorded with a dry period of 51 to 60d compared with longer dry periods. The incidence of calving difficulty did not differ in cows with 51- to 60-d dry period compared with cows with 0- to 35-d and 36- to 50-d dry periods. In conclusion, the results of this study did not support previous findings that suggested a shorter dry period could be beneficial to dairy production.

The impact of length of second stage of labor on shoulder dystocia outcomes: a retrospective cohort study.

OBJECTIVE: To compare obstetrical and neonatal outcomes of vaginal deliveries complicated by shoulder dystocia, according to the length of second stage of labor. METHODS: We conducted a retrospective cohort study of 177 shoulder dystocia cases that were divided into three categories according to second stage duration (1-20, 21-59, 60-180 min, respectively). The three categories were compared in terms of obstetric characteristics and neonatal outcomes. Statistical analysis utilized the χ2-test and analysis of variance where appropriate. The odds ratios of brachial plexus injury and having a 5-min APGAR score <7 across the second stage duration categories were calculated using logistic regression models that adjusted for potential confounders. RESULTS: The incidence of brachial plexus injury was 5.4% (1st category), 4.4% (2nd category) and 26.9% (3rd category); P<0.01. The higher incidence of brachial plexus injury in the group where second stage lasted >1 h was confirmed by logistic regression, with and without adjusting for confounders. CONCLUSIONS: The incidence of brachial plexus injury increases with the length of second stage, even after controlling for confounders.

Short communication: survival, growth to weaning, and subsequent fertility of live-born dairy heifers after a difficult birth.

The experience of a difficult birth (dystocia) is traumatic and has adverse effects on the newborn in various species. Despite affecting up to 1 in 3 births in dairy cattle, studies on calves have been mostly limited to the first day of life. The objective of this study was to investigate the effects of dystocia on the survival to calving, growth to weaning, and subsequent fertility as nulliparous animals. Historical data from live-born Holstein heifer calves born from cows with various birth difficulty scores (no assistance; moderate; high difficulty) were obtained from 2 herds (Edinburgh herd: n=1,237; Crichton Royal Farm herd: n=721). Each herd was analyzed separately for birth weights, weaning weights, growth rate to weaning, number of services to conception, and age at first calving using REML and generalized linear mixed model analyses. Survival analysis (Cox proportional hazards model) was used in the Edinburgh herd to analyze the subsequent survival of live-born heifers, whereas descriptive data are presented for the Crichton Royal Farm herd. A higher mortality risk to weaning and to first service was observed in the live-born heifers that experienced moderate difficulty at birth compared with heifers born naturally. Surviving dystocial heifers had similar growth-to-weaning and fertility performance as heifers born naturally in both herds. It could be that the performance of dystocial heifers that survived to weaning was not affected or that it was compensated for by farm management. This study highlights long-term effects of the early experience of a difficult birth and thereby stresses the importance of preventing dystocia not just from the point of view of the adult cow, but also from the perspective of the calf. This would also improve farm efficiency and calf welfare.