The test accuracy of antenatal ultrasound definitions of fetal macrosomia to predict birth injury: A systematic review.

OBJECTIVES: To determine which ultrasound measurement for predicted fetal macrosomia most accurately predicts adverse delivery and neonatal outcomes. STUDY DESIGN: Four biomedical databases searched for studies published after 1966. Randomised trials or observational studies of women with singleton pregnancies, resulting in a term birth who have undergone an index test of interest measured and recorded as predicted fetal macrosomia ≥28 weeks. Adverse outcomes of interest included shoulder dystocia, brachial plexus injury (BPI) and Caesarean section. RESULTS: Twenty-five observational studies (13,285 participants) were included. For BPI, the only significant positive association was found for Abdominal Circumference (AC) to Head Circumference (HC) difference > 50 mm (OR 7.2, 95 % CI 1.8-29). Shoulder dystocia was significantly associated with abdominal diameter (AD) minus biparietal diameter (BPD) ≥ 2.6 cm (OR 4.2, 95 % CI 2.3-7.5, PPV 11 %) and AC > 90th centile (OR 2.3, 95 % CI 1.3-4.0, PPV 8.6 %) and an estimated fetal weight (EFW) > 4000 g (OR 2.1 95 %CI 1.0-4.1, PPV 7.2 %). CONCLUSIONS: Estimated fetal weight is the most widely used ultrasound marker to predict fetal macrosomia in the UK. This study suggests other markers have a higher positive predictive value for adverse outcomes associated with fetal macrosomia.

Randomized Trial of Labor Induction in Women 35 Years of Age or Older.

BACKGROUND: The risk of antepartum stillbirth at term is higher among women 35 years of age or older than among younger women. Labor induction may reduce the risk of stillbirth, but it also may increase the risk of cesarean delivery, which already is common in this older age group. METHODS: We conducted a randomized, controlled trial involving primigravid women who were 35 years of age or older. Women were randomly assigned to labor induction between 39 weeks 0 days and 39 weeks 6 days of gestation or to expectant management (i.e., waiting until the spontaneous onset of labor or until the development of a medical problem that mandated induction). The primary outcome was cesarean delivery. The trial was not designed or powered to assess the effects of labor induction on stillbirth. RESULTS: A total of 619 women underwent randomization. In an intention-to-treat analysis, there were no significant between-group differences in the percentage of women who underwent a cesarean section (98 of 304 women in the induction group [32%] and 103 of 314 women in the expectant-management group [33%]; relative risk, 0.99; 95% confidence interval [CI], 0.87 to 1.14) or in the percentage of women who had a vaginal delivery with the use of forceps or vacuum (115 of 304 women [38%] and 104 of 314 women [33%], respectively; relative risk, 1.30; 95% CI, 0.96 to 1.77). There were no maternal or infant deaths and no significant between-group differences in the women's experience of childbirth or in the frequency of adverse maternal or neonatal outcomes. CONCLUSIONS: Among women of advanced maternal age, induction of labor at 39 weeks of gestation, as compared with expectant management, had no significant effect on the rate of cesarean section and no adverse short-term effects on maternal or neonatal outcomes. (Funded by the Research for Patient Benefit Programme of the National Institute for Health Research; Current Controlled Trials number, ISRCTN11517275.).

Causes of antepartum stillbirth in women of advanced maternal age.

OBJECTIVES: To breakdown the causes of antepartum stillbirth by maternal age. STUDY DESIGN: Observational study. SETTING: UK. SAMPLE: Anonymised national data on 2850 cases of antepartum stillbirth in 2009. STATISTICAL ANALYSIS: The association between cause of stillbirth and maternal age was examined using an adjusted multinomial logistic regression model. Risk ratios were calculated relative to stillbirth due to haemorrhage. MAIN OUTCOME MEASURES: Antepartum stillbirths classified by the Centre for Maternal and Child Enquiries (CMACE) classification. RESULTS: Stillbirths in women aged 35 years and over are more likely to be due to major congenital anomalies (relative risk ratio (RRR) 2.0, 95% CI 1.3-3.0), mechanical causes (RRR 1.6, 95% CI 1.0-2.6), maternal disorders (RRR 2.1, 95% CI 1.2-3.6) or associated obstetric factors (RRR 2.1, 95% CI 1.1-3.9) than women less than 35. Women aged 35 years and over have a statistically significant increased risk of stillbirth due to major congenital anomalies (OR relative to live birth 1.6, 95% CI 1.3-1.9) and maternal disorders (OR 1.7, 95% CI 1.2-2.4) than younger women. Women aged 35 years and over were 30% more likely to experience a term stillbirth than women <35 years (OR 1.3, 95% CI 1.1-1.5). Stillbirth due to congenital anomaly was statistically significantly more likely in women ≥ 35 years. CONCLUSIONS: Advanced maternal age is a significant risk factor for antepartum stillbirth particularly at term. Attention should be given to stillbirth due to mechanical causes, maternal disorders and associated obstetric factors in such women.

Childbirth experience questionnaire: validating its use in the United Kingdom.

BACKGROUND: The Childbirth Experience Questionnaire (CEQ) was developed in Sweden in 2010 and validated in 920 primiparous women. It has not been validated in the United Kingdom (UK). Measuring the impact of an intervention on a woman's childbirth experience is arguably as important as measuring its impact on outcomes such as caesarean delivery and perinatal morbidity or mortality and yet surprisingly it is rarely done. The lack of a robust validated tool for evaluating labour experience in the UK is a topical issue in the UK at present. Indeed NICE say 'A standardised method to measure and quantify women's psychological and emotional wellbeing and their birth experiences is urgently required to support any study investigating the effectiveness of interventions, techniques or strategies during birth.' METHODS: The Childbirth Experience Questionnaire and part of the Care Quality Commission Maternity Survey (2010) was sent to 350 women at one month postnatal. The CEQ was sent again two weeks later. The CEQ was tested for face validity among 25 postnatal mothers. Demographic data and delivery data was used to establish construct validity of the CEQ using the method of known-groups validation. The results of the scored CEQ sent out twice were used to measure test-retest reliability of the CEQ by calculating the quadratic weighted index of agreement between the two scores. Criterion validity was measured by calculating the Pearson correlation coefficient for the CEQ and Maternity Survey scores. RESULTS: Face validity of the CEQ in a UK population was demonstrated with all respondents stating it was easy to understand and complete. A statistically significantly higher CEQ score for subgroups of women known to report a better birth outcome demonstrated construct validity of the CEQ. A weighted kappa of 0.68 demonstrated test-retest reliability of the CEQ. A Pearson correlation co-efficient of 0.73 demonstrated a strong correlation between the results of the CEQ and the results of the 'gold standard' assessment of childbirth experience in the UK: the Maternity Survey and hence criterion validity of the CEQ. CONCLUSIONS: The Childbirth Experience Questionnaire is a valid and reliable measure of childbirth experience in the UK population.

Oxytocin versus no treatment or delayed treatment for slow progress in the first stage of spontaneous labour.

BACKGROUND: Slow progress in the first stage of spontaneous labour is associated with an increased caesarean section rate and fetal and maternal morbidity. Oxytocin has long been advocated as a treatment for slow progress in labour but it is unclear to what extent it improves the outcomes for that labour and whether it actually reduces the caesarean section rate or maternal and fetal morbidity. This review will address the use of oxytocin and whether it improves the outcomes for women who are progressing slowly in labour compared to situations where it is not used or where its administration is delayed. OBJECTIVES: To determine if the use of oxytocin for the treatment of slow progress in the first stage of spontaneous labour is associated with a reduction in the incidence of caesarean sections, or maternal and fetal morbidity compared to situations where it is not used or where its administration is delayed. SEARCH METHODS: We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (23 February 2013) and bibliographies of relevant papers. SELECTION CRITERIA: Randomised controlled trials which compared oxytocin with either placebo, no treatment or delayed oxytocin in the active stage of spontaneous labour in low-risk women at term. DATA COLLECTION AND ANALYSIS: Two authors independently assessed studies for inclusion, assessed risk of bias and extracted data. We sought additional information from trial authors. MAIN RESULTS: We included eight studies in the review involving a total of 1338 low-risk women in the first stage of spontaneous labour at term. Two comparisons were made; 1) the use of oxytocin versus placebo or no treatment (three trials); 2) the early use of oxytocin versus its delayed use (five trials). There were no significant differences in the rates of caesarean section or instrumental vaginal delivery in either comparison. Early use of oxytocin resulted in an increase in uterine hyperstimulation associated with fetal heart changes. However, the early use of oxytocin versus its delayed use resulted in no significant differences in a range of neonatal and maternal outcomes. Use of early oxytocin resulted in a statistically significant reduction in the mean duration in labour of approximately two hours but did not increase the normal delivery rate. There was significant heterogeneity for this analysis and we carried out a random-effects meta-analysis; however, all of the trials are strongly in the same direction so it is reasonable to conclude that this is the true effect. We also performed a random-effects meta-analysis for the four other analyses which showed substantial heterogeneity in the review. AUTHORS' CONCLUSIONS: For women making slow progress in spontaneous labour, treatment with oxytocin as compared with no treatment or delayed oxytocin treatment did not result in any discernable difference in the number of caesarean sections performed. In addition there were no detectable adverse effects for mother or baby. The use of oxytocin was associated with a reduction in the time to delivery of approximately two hours which might be important to some women. However, if the primary goal of this treatment is to reduce caesarean section rates, then doctors and midwives may have to look for alternative options.

Induction of labour at term for women over 35 years old: a survey of the views of women and obstetricians.

OBJECTIVES: To determine the views of UK women and obstetricians relating to induction of labour at term for women over 35 years of age. STUDY DESIGN: Cross-sectional web-based survey sent to members of the British Maternal and Fetal Medicine Society (BMFMS) and pregnant or recently delivered members of a large social network site for parents (www.mumsnet.com). One hundred and twenty-eight consultant obstetrician members of BMFMS and 663 pregnant or recently delivered women responded. RESULTS: Two hundred and eighty-eight women (43%) would consider induction of labour for maternal age alone, and 192 women (29%) would consider participating in a randomised trial of induction of labour at term versus expectant management in a future pregnancy. Three percent (n=4) of consultant obstetricians offer induction of labour at term to women at 35-39 years of age, 37% (n=47) to women at 40-44 years of age and 55% (n=70) to those over 45 years. Sixty-one consultants (48%) would participate in a trial to test the effect of a policy of induction for nulliparous women over 35 years old. CONCLUSIONS: The policy of offering induction of labour at term for advanced maternal age is widespread and a significant percentage of women consider it to be a valid indication.

Oxytocin versus no treatment or delayed treatment for slow progress in the first stage of spontaneous labour.

BACKGROUND: Slow progress in the first stage of spontaneous labour is associated with an increased caesarean section rate and fetal and maternal morbidity. Oxytocin has long been advocated as a treatment for slow progress in labour but it is unclear to what extent it improves the outcomes for that labour and whether it actually reduces the caesarean section rate or maternal and fetal morbidity. This review will address the use of oxytocin and whether it improves the outcomes for women who are progressing slowly in labour compared to situations where it is not used or where its administration is delayed. OBJECTIVES: To determine if the use of oxytocin for the treatment of slow progress in the first stage of spontaneous labour is associated with a reduction in the incidence of caesarean sections, or maternal and fetal morbidity compared to situations where it is not used or where its administration is delayed. SEARCH STRATEGY: We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (30 April 2011) and bibliographies of relevant papers. SELECTION CRITERIA: Randomised controlled trials which compared oxytocin with either placebo, no treatment or delayed oxytocin in the active stage of spontaneous labour in low-risk women at term. DATA COLLECTION AND ANALYSIS: Two authors independently assessed studies for inclusion, assessed risk of bias and extracted data. We sought additional information from trial authors. MAIN RESULTS: We included eight studies in the review involving a total of 1338 low-risk women in the first stage of spontaneous labour at term. Two comparisons were made; 1) the use of oxytocin versus placebo or no treatment (three trials); 2) the early use of oxytocin versus its delayed use (five trials). There were no significant differences in the rates of caesarean section or instrumental vaginal delivery in either comparison. Early use of oxytocin resulted in an increase in uterine hyperstimulation associated with fetal heart changes. However, the early use of oxytocin versus its delayed use resulted in no significant differences in a range of neonatal and maternal outcomes. Use of early oxytocin resulted in a statistically significant reduction in the mean duration in labour of approximately two hours but did not increase the normal delivery rate. There was significant heterogeneity for this analysis and we carried out a random-effects meta-analysis; however, all of the trials are strongly in the same direction so it is reasonable to conclude that this is the true effect. We also performed a random-effects meta-analysis for the four other analyses which showed substantial heterogeneity in the review. AUTHORS' CONCLUSIONS: For women making slow progress in spontaneous labour, treatment with oxytocin as compared with no treatment or delayed oxytocin treatment did not result in any discernable difference in the number of caesarean sections performed. In addition there were no detectable adverse effects for mother or baby. The use of oxytocin was associated with a reduction in the time to delivery of approximately two hours which might be important to some women. However, if the primary goal of this treatment is to reduce caesarean section rates, then doctors and midwives may have to look for alternative options.

Evaluating the intra- and interobserver reliability of three-dimensional ultrasound and power Doppler angiography (3D-PDA) for assessment of placental volume and vascularity in the second trimester of pregnancy.

Three-dimensional (3-D) power Doppler angiography (3-D-PDA) allows visualisation of Doppler signals within the placenta and their quantification is possible by the generation of vascular indices by the 4-D View software programme. This study aimed to investigate intra- and interobserver reproducibility of 3-D-PDA analysis of stored datasets at varying gestations with the ultimate goal being to develop a tool for predicting placental dysfunction. Women with an uncomplicated, viable singleton pregnancy were scanned at 12, 16 or 20 weeks gestational age groups. 3-D-PDA datasets acquired of the whole placenta were analysed using the VOCAL software processing tool. Each volume was analysed by three observers twice in the A plane. Intra- and interobserver reliability was assessed by intraclass correlation coefficients (ICCs) and Bland Altman plots. At each gestational age group, 20 low risk women were scanned resulting in 60 datasets in total. The ICC demonstrated a high level of measurement reliability at each gestation with intraobserver values >0.90 and interobserver values of >0.6 for the vascular indices. Bland Altman plots also showed high levels of agreement. Systematic bias was seen at 20 weeks in the vascular indices obtained by different observers. This study demonstrates that 3-D-PDA data can be measured reliably by different observers from stored datasets up to 18 weeks gestation. Measurements become less reliable as gestation advances with bias between observers evident at 20 weeks.

Outcomes of labours augmented with oxytocin.

OBJECTIVE: To highlight the differences in mode of delivery between women augmented with intravenous oxytocin because of failure to progress in labour with those who labour without the need for augmentation. STUDY DESIGN: An incidence study over a 5-year-period in a tertiary referral hospital comparing 1097 nulliparous women who were augmented in labour with 2745 nulliparous women who did not need augmentation. Only labours of spontaneous onset in the pregnancies of women at term were studied. The incidence of pregnancy outcomes were assessed by presenting estimates of relative risk (RR) and their 95% confidence intervals (CI). RESULTS: Only 51.1% of women who received augmentation achieved a normal vaginal delivery compared with 76.5% of women who did not need augmentation (RR 0.67; CI 0.63-0.71). Contributory factors to this disparity included a greater number of Caesarean sections (14.4% versus 6.6%; RR 2.18 CI 1.74-2.67), forcep deliveries (12.8% versus 5.3%; RR 2.41 CI 1.93-3.01) and ventouse deliveries (21.7% versus 11.5%; RR 1.89 CI 1.62-2.21) being performed among augmented labours as compared to normal progressive labours. CONCLUSION: Significant improvements in the management of labours which fail to progress are needed if normal vaginal delivery rates are to approach those seen in labours which progress without the need for augmentation.

Expression of TASK and TREK, two-pore domain K+ channels, in human myometrium.

Two-pore domain K+ channels are an emerging family of K+ channels that may contribute to setting membrane potential in both electrically excitable and non-excitable cells and, as such, influence cellular function. The human uteroplacental unit contains both excitable (e.g. myometrial) and non-excitable cells, whose function depends upon the activity of K+ channels. We have therefore investigated the expression of two members of this family, TWIK (two-pore domain weak inward rectifying K+ channel)-related acid-sensitive K+ channel (TASK) and TWIK-related K+ channel (TREK) in human myometrium. Using RT-PCR the mRNA expression of TASK and TREK isoforms was examined in myometrial tissue from pregnant women. mRNAs encoding TASK1, 4 and 5 and TREK1 were detected whereas weak or no signals were observed for TASK2, TASK3 and TREK2. Western blotting for TASK1 gave two bands of approximately 44 and 65 kDa, whereas TREK1 gave bands of approximately 59 and 90 kDa in myometrium from pregnant women. TASK1 and TREK1 immunofluorescence was prominent in intracellular and plasmalemmal locations within myometrial cells. Therefore, we conclude that the human myometrium is a site of expression for the two-pore domain K+ channel proteins TASK1 and TREK1.