Search

Background: Induction of labour is associated with a reduction in caesarean delivery, but the mechanism of action and which groups of women might benefit remain unknown., Aims: To assess the association between induction of labour at 38-39 weeks pregnancy, and caesarean delivery: (i) overall; (ii) for slow progress in labour; and (iii) for suspected fetal compromise., Material and Methods: Retrospective observational study in two Sydney hospitals from 2009 to 2016, among nulliparous women with induction of labour at 38 or 39 completed weeks pregnancy and a singleton, cephalic presenting fetus. The comparator was all planned vaginal births beyond 39 (+1/7) weeks, whether or not labour was induced. Binary and multinomial multiple logistic regressions adjusting for multiple confounders were performed., Results: There were 2388 and 15 259 women in the study and comparison groups respectively. Induction of labour was associated with caesarean delivery overall only for women <25 years of age (adjusted odds ratio 1.63; 95% CI 1.17-2.27) and was not associated with caesarean delivery for slow progress. Induction of labour was positively associated with increased caesarean delivery for suspected fetal compromise among young women (<30 years), with the association weakening as maternal age increased. The association between induction of labour and caesarean delivery was different for slow progress compared with suspected compromise (P = 0.005)., Conclusions: Induction of labour has different effects on the likelihood of caesarean delivery for slow progress and for suspected fetal compromise. Women <30 years of age are at higher risk of caesarean delivery for suspected fetal compromise, potentially due to uterine hyperstimulation., (© 2019 The Royal Australian and New Zealand College of Obstetricians and Gynaecologists.)

Background: First-trimester miscarriage is common, with women increasingly offered an ultrasound scan early in the first trimester to assess the status of their pregnancy. Ultrasound is uniquely situated to significantly impact the clinical management of these women., Aims: This study aims to determine whether there were any differences in the early ultrasound appearances of pregnancies that continued to be viable or resulted in miscarriage before 12 weeks gestation., Materials and Methods: This was a prospective cohort study including ultrasound measurements: mean sac diameter (MSD), yolk sac diameter (YSD), crown-rump length (CRL), fetal heart rate (FHR), trophoblast thickness, trophoblast volume (TTV) and mean uterine artery pulsatility index (meanUAPI). Regression models were fitted for each parameter and Z-scores compared between cohorts that progressed or miscarried after the scan but before 12 weeks gestation. Logistic regression analysis was used to create a prediction model for miscarriage prior to 12 weeks gestation based on the standardised ultrasound measurements recorded during the early first-trimester scan., Results: Comparison of Z-Scores for meanUAPI, TTV, FHR and MSD demonstrated significant variation between the two groups. The proposed logistic regression model resulted in an area under the receiver operator curve of 0.81. At a false-positive rate of 30%, the model resulted in a sensitivity of 76% (95% CI 64-89%)., Conclusion: The combination of FHR, meanUAPI, TTV in a prediction model for miscarriage may prove to be of value for ongoing pregnancy management in the first trimester., (© 2019 The Royal Australian and New Zealand College of Obstetricians and Gynaecologists.)

Background: Knowledge of the outcomes of induction of labour for different indications is sparse., Aims: To describe the mode of birth and other outcomes for nulliparous women induced at 38-39 weeks gestational age by indication for induction of labour., Material and Methods: This was a retrospective observational study in a tertiary referral hospital, and a metropolitan teaching hospital in Sydney. The study population was nulliparous women with induction of labour at 38 or 39 completed weeks of pregnancy and a singleton, cephalic presenting baby planning a vaginal birth, from 2009 to 2016. The indication for induction of labour was classified into 12 groups. Mode of birth and other maternal and perinatal outcomes were described in each group, for women who spontaneously laboured at 38 or 39 weeks, and for women who gave birth from 40 completed weeks onward. The main outcome measure was mode of birth., Results: There were 3330 women with induction of labour at 38 or 39 weeks gestation. Rates of vaginal birth varied widely, ranging from 54% when the indication for induction was suspected large fetus, to 82% when the indication was suspected fetal compromise, and was 74% overall. Indications for caesarean delivery also varied by indication for induction. Among women giving birth ≥40 weeks gestational age, 75% had a vaginal birth., Conclusions: In nulliparous women, rates of vaginal birth following induction of labour at 38 or 39 weeks gestation vary widely according to the indication for induction. These data are useful for antenatal counselling., (© 2018 The Royal Australian and New Zealand College of Obstetricians and Gynaecologists.)

Background: There are global concerns regarding excessive caesarean rates, which could be reduced by identification of risk factors leading to preventative measures such as induction of labour., Aims: This study aims to describe the association between antenatal ultrasound and emergency caesarean section for: (i) failure to progress; (ii) other indications; and (iii) any indication., Materials and Methods: Women who had an ultrasound in pregnancy between 36 (+0/7) to 38 (+6/7) weeks at Royal Prince Alfred Hospital from January 2005 to June 2009 were included. Ultrasound parameters were linked to clinical parameters from the maternity database. Missing clinical data were imputed and multiple logistic regression performed., Results: Fetal biometry data were available for 2006 pregnancies. After adjusting for maternal age, height, body mass index, parity, previous caesarean section and diabetes, caesarean section for failure to progress was associated with estimated fetal weight (odds ratio (OR) 2.24 (95% CI: 1.76-2.84) per 500 g increase); or biparietal diameter (OR 1.51 (1.16-1.97) per 5 mm increase) and abdominal circumference (OR for the 4th quartile (>75th centile) compared with the 10-25th centile group was 2.09 (1.13-3.85)).* There were also non-linear associations between components of fetal biometry and caesarean section for fetal distress and for any indication., Conclusions: Components of fetal biometry in the third trimester are associated with intrapartum caesarean section for failure to progress. These parameters could be incorporated into models to predict emergency caesarean section which could lead to implementation of preventative strategies. *[Corrections added on 29 January 2018, after first online publication, '(OR for the 4th quartile (>7th centile)' has been changed to '(OR for the 4th quartile (>75th centile)'.]., (© 2017 The Royal Australian and New Zealand College of Obstetricians and Gynaecologists.)

Objective: To compare birth weights in central Sydney to the INTERGROWTH21st international standard to describe current trends in relation to optimal growth and to define areas that may benefit from improved obstetric surveillance and intervention., Methods: Retrospective analysis of prospectively collected cohort., Design: hospital-based cohort study., Setting: Sydney Local Health District, Australia., Population or Sample: women with singleton pregnancies who had first trimester screening for aneuploidy between 16 April, 2010 and 9 March, 2012. Analysis of 2966 births., Main Outcome Measures: Large for gestational age (LGA) >4000 g, >4500 g, >5000 g, >90th, >95th, >97th centiles and small for gestational age (SGA) <1500 g, <2500 g,

Background: There is global concern about rising caesarean section rates. Identification of risk factors could lead to preventative measures., Aims: To describe the association between neonatal head circumference and (i) caesarean section for failure to progress, (ii) intrapartum caesarean section overall., Materials and Methods: This was a retrospective cohort study of 11 687 singleton live births with cephalic presentation, attempted vaginal birth and at least 37 completed weeks gestation from January 2005 to June 2009. Neonatal head circumference was grouped into quartiles and multiple logistic regressions performed., Results: The rates of caesarean section for failure to progress were 4.1, 6.4, 8.8 and 14.3% in successive head circumference quartiles. Rates of intrapartum caesarean section overall were 8.7, 12.1, 15.8 and 21.5%. The odds ratios for caesarean section for failure to progress were: 1.00, 1.33 (95% CI 1.02- 1.73), 1.54 (1.18-2.02) and 1.93 (1.44-2.57) for successive head circumference quartiles after adjusting for multiple demographic and clinical factors. The adjusted odds ratios for intrapartum caesarean section for any indication were: 1.00, 1.52 (95% CI 1.24-1.87), 1.99 (1.62-2.46) and 2.38 (1.89-3.00), respectively., Conclusions: There is a strong positive relationship between head circumference quartile and both caesarean section for failure to progress and caesarean for any indication. If this finding is confirmed using ultrasound measurements, there is potential for head circumference to be incorporated into predictive models for intrapartum caesarean section with a view to offering interventions to reduce the risk of caesarean section., (© 2016 The Royal Australian and New Zealand College of Obstetricians and Gynaecologists.)

Aim: To determine the feasibility of a multicentre randomised controlled trial (RCT) to investigate whether digital rotation of the fetal head from occiput posterior (OP) position in the second stage of labour reduces the risk of operative delivery (defined as caesarean section (CS) or instrumental delivery)., Methods: We conducted the study between December 2010 and December 2011 in a tertiary referral hospital in Australia. A transabdominal ultrasound was performed early in the second stage of labour on women with cephalic, singleton pregnancies to determine the fetal position. Those women with a fetus in the OP position were randomised to either a digital rotation or a sham procedure. In all other ways, participants received their usual intrapartum care. Data regarding demographics, mode of delivery, labour, post natal period and neonatal outcomes were collected., Results: One thousand and four women were consented, 834 achieved full dilatation, and 30 were randomised. An additional portable ultrasound scan and a blinded 'sham' digital rotation were acceptable to women and staff. Operative delivery rates were 13/15 in the digital rotation (four CS and nine instrumental) and 12/15 in the sham (three CS and nine instrumental) groups, respectively., Conclusion: A large double-blinded multicentre RCT would be feasible and acceptable to women and staff. Strategies to improve recruitment such as consenting women with an effective epidural in active labour should be considered. This would be the first RCT to answer a clinically important question which could significantly affect the operative delivery rate in Australia and internationally., (© 2014 The Royal Australian and New Zealand College of Obstetricians and Gynaecologists.)

Background: Using a fixed cut-off of ≤25 mm, ultrasound assessment of cervical length during the 18-23 week anomaly scan has been shown to identify approximately 50% of pregnancies that would deliver prior to 34 weeks., Aim: To determine whether a policy of reverting to transvaginal cervical assessment only if the cervix appears short (≤25 mm) on transabdominal assessment affects the efficiency of screening., Methods: Women with a singleton pregnancy that presented for a routine anomaly scan had their cervical length assessed transabdominally, initially with the maternal bladder full (TABF) and then empty (TABE). Cervical length was then assessed transvaginally (TV)., Results: One hundred and ninety-eight women agreed to participate in the study. Identification of the internal and external cervical os was possible during TABF, TABE and TV sonography in 97.0, 82.8 and 100%, respectively. Compared with TV sonography, TABF overestimates cervical length (6.1 mm difference in median values; P < 0.01). There was no significant difference between TV and TABE. However, TABE assessment was not possible in one in six women. If TABF sonography was to be used as a screening tool and using ≤25 mm as the critical cut-off, the sensitivity and specificity was 15.4 and 93.2%, respectively., Conclusion: This study has shown that assessment of cervical length using a TA approach is only routinely possible when the bladder is full. However, measurements are significantly overestimated. Therefore, we feel that TV assessment of cervical length is the preferred method of reliable cervical assessment. As such, all women should be offered a TV assessment of cervical length at the time of the fetal anomaly ultrasound as a screening test for preterm birth., (© 2014 The Royal Australian and New Zealand College of Obstetricians and Gynaecologists.)

Background: The aim of this study is to validate the Fetal Medicine Foundation (FMF) multiple logistic regression algorithm for prediction of risk of pre-eclampsia in an Australian population. This model, which predicts risk using the population rate of pre-eclampsia, a variety of demographic factors, mean maternal arterial blood pressure (MAP), uterine artery PI (UtA PI) and pregnancy-associated plasma protein A (PAPP-A), has been shown to predict early-onset pre-eclampsia (delivery prior to 34 weeks) in 95% of women at a 10% false-positive rate., Methods: All women who attended first trimester screening at the Royal Prince Alfred Hospital had their body mass index (BMI), MAP and UtA PI assessed in addition to factors traditionally used to assess aneuploidy (including PAPP-A MoM). After delivery, risks of early-onset (delivery prior to 34 weeks) pre-eclampsia, late pre-eclampsia and gestational hypertension were calculated using the FMF risk algorithm., Results: A total of 3099 women were screened and delivered locally. 3066 (98.9%) women had all data to perform pre-eclampsia screening available. This included 3014 (98.3%) women with a live birth, where risks of early pre-eclampsia were calculated. Twelve women were delivered before 34 weeks because of early pre-eclampsia with a prevalence of early pre-eclampsia of 1 in 256 pregnancies. Risks generated through the use of maternal history, MAP, UtA PI and PAPP-A detected 41.7 and 91.7% of early pre-eclampsia at a false-positive rate of 5 and 10%, respectively., Conclusions: This study shows that the FMF early pre-eclampsia algorithm is effective in an Australian population., (© 2013 The Royal Australian and New Zealand College of Obstetricians and Gynaecologists.)

Background: Issues in the management of the occipito posterior (OP) position have been the subject of clinical controversy over decades. Manual rotation has the potential to reduce operative delivery for fetal malposition., Aim: To determine the current obstetric practice with regard to manual rotation in the management of the second stage of labour., Methods: Survey mailed to all members and fellows of the Australian and New Zealand College of Obstetricians and Gynaecologists., Results: Of 1805 surveyed, 60% responded, of whom 68% were currently practising obstetrics. Ninety-seven per cent of respondents thought that manual rotation at full dilatation was a valid intervention, 85% stated that manual rotation was acceptable prior to instrumental delivery, and 70% thought that manual rotation was acceptable without assisted delivery. Only 41% of practising obstetricians had performed a manual rotation in the last year, and only 9% had performed more than five. Obstetricians would routinely perform manual rotation for OP position if it reduced operative delivery from 68% to a median of 50%., Conclusion: Manual rotation is currently performed by only a minority of obstetricians in Australia and New Zealand, yet is considered to be an acceptable procedure by the vast majority. The survey confirmed that obstetricians would be willing to perform prophylactic manual rotation if this was known to reduce the operative delivery rate, suggesting that there is a scope to introduce this procedure into widespread clinical practice., (© 2012 The Authors ANZJOG © 2012 The Royal Australian and New Zealand College of Obstetricians and Gynaecologists.)

Objective: An absent or short nasal bone is highly predictive of Down syndrome in Caucasian populations, but Asians may have shorter nasal bones - increasing the false positive rate of screening. We examine differences in nasal bone length (NBL) in Caucasian and Asian populations., Methods: This prospective cohort study involved pregnant women attending for their routine anomaly scan at 18-20 weeks' gestation. Ethnicity of the patient and their partner was recorded, and the nasal bone was measured three times. Mean NBL was calculated and used to investigate the effect of ethnicity first with a simple linear regression model and second with a mixed-effects regression model that accounted for variability of measurement between sonographers., Results: A total of 1087 families were involved in the study, including 592 (54%) Caucasians, 214 (20%) East Asians, 110 (10%) South Asians and 171 (16%) West Asians. Twenty-three sonographers performed the scans with an average of 19 scans each. There is no significant difference in NBL between Caucasian and Asian populations. The mixed-effects model shows that accounting for sonographer variation is important, with 6.7% of the total variance in measurement being related to this random effect., Conclusions: There is no significant difference in NBL between Caucasian and Asian populations. It is reasonable to use criteria established in a Caucasian population to define the characteristics of an absent/short nasal bone in Asian fetuses. This finding also removes difficulties in counselling mixed race couples., (© 2010 The Authors. Australian and New Zealand Journal of Obstetrics and Gynaecology © 2010 The Royal Australian and New Zealand College of Obstetricians and Gynaecologists.)

Background: Nuchal translucency (NT) measurement is the ultrasound component of first trimester combined screening for Down syndrome. In 2002, a NT ultrasound education and monitoring program was established in Australia. Between 2002 and 2008, a total of 728,502 NT scans were audited through this process. OVERALL AIM: To audit the availability and performance of certified operators measuring NT following implementation of the Australian education and monitoring program in 2002., Methods: Retrospective review of the central database that is used to monitor performance of individuals and practices performing NT scans in both public and private practice settings throughout Australia between 2002 and 2008. The performance of operators was assessed by a widely used international standard - that 40-60% of NT measurements should be above the median value for gestational age., Results: The number of certified operators has increased (from 184 in 2002 to 477 in 2008). There is wide variation between states in the number of operators per birth. The percentage of certified operators with a measurement distribution meeting the international standard has increased from 40% in 2002 to 55% in 2008. Greatest improvement has been seen in operators performing 30-199 scans per year. There has been no overall improvement in performance over the last three audit cycles., Conclusions: The number of operators certified to perform the NT scan has increased since 2002, although availability in some states remains low. An initial improvement in performance of operators appears to have reached a plateau. It is time to become more proactive in engaging operators in the audit cycle., (© 2010 The Authors. Australian and New Zealand Journal of Obstetrics and Gynaecology © 2010 The Royal Australian and New Zealand College of Obstetricians and Gynaecologists.)