Obstetrics and Gynaecology - Research Publications
Permanent URI for this collection
Search Results
1 - 4 of 4
-
ItemRisk of obstetric anal sphincter injury among women who birth vaginally after a prior caesarean section: A state-wide cohort study(WILEY, 2022-07)OBJECTIVE: Vaginal birth after caesarean (VBAC) has been suggested to be associated with an increased risk of obstetric anal sphincter injury (compared with primiparous women who birth vaginally). However, prior studies have been small or have used outdated methodology. We set out to validate whether the risk of obstetric anal sphincter injury among women having their first VBAC is greater than that among primiparous women having a vaginal birth. DESIGN: State-wide retrospective cohort study. SETTING: Victoria, Australia. POPULATION: All births (455 000) between 2009 and 2014. METHODS: The risk of severe perineal injury between the first vaginal birth and the first VBAC was compared, after adjustment for potential confounding variables. Covariates were examined using logistic regression for categorical data and the Wilcoxon rank-sum test for continuous data. Missing data were handled using multiple imputation; the analysis was performed using regression adjustment and stata 16 multiple imputation and suite of effects commands. RESULTS: Women having a VBAC (n = 5429) were significantly more likely than primiparous women (n = 123 353) to sustain a third- or fourth-degree tear during vaginal birth (7.1 versus 5.7%, p < 0.001). After adjustment for mode of birth, body mass index, maternal age, infant birthweight, episiotomy and epidural, there was a 21% increased risk of severe perineal injury (RR 1.21, 95% CI 1.07-1.38). CONCLUSIONS: Women having their first VBAC have a significantly increased risk of sustaining a third- or fourth-degree tear, compared with primiparous women having a vaginal birth. Patient counselling and professional guidelines should reflect this increased risk.
-
ItemCustomised growth charts in large-for-gestational-age infants and the association with emergency caesarean section rate(WILEY, 2019-06)BACKGROUND AND AIM: Large-for-gestational-age (LGA) infants are at increased risk of intrapartum complications. However, some infants classified as LGA may be appropriate-for-gestational-age (AGA) if adjusted for maternal stature. We determined whether customisation of birthweight centiles by maternal height, or height and weight, improves the detection of LGA infants at risk of complications. METHODS: We conducted a retrospective analysis of 38 246 term, singleton nulliparous women. We compared population birthweight centiles to those customised by height, or height and weight for complications including intrapartum caesarean section, instrumental delivery, postpartum haemorrhage, anal sphincter injury and neonatal outcomes. RESULTS: Those considered LGA when customised for height but AGA by population centiles (LGA-ht-only) were at increased risk of intrapartum emergency caesarean section compared with infants AGA on all charts (AGA-all); odds ratio (OR) 4.64, 95% CI 3.22-6.76. In contrast, infants considered LGA on population charts, but AGA when customised by height (LGA-pop-only) were not at increased risk compared to the AGA-all group (OR 1.43, 95% CI 0.70-1.88). Infants classified as LGA-ht-only compared to LGA-pop-only remained at significantly higher risk after adjustment for potential confounders (aOR 3.27; 95% CI 2.02-5.31). No difference was seen for any other outcomes. No benefit was seen with customisation by both maternal height and weight. CONCLUSION: Women with an infant classified as AGA on population centiles but LGA when customised for height are at increased risk of intrapartum caesarean section. This is a population unrecognised in current practice. Fetal growth should be customised for maternal height when making assessments regarding the LGA infant.
-
ItemRisk of major labour-related complications for pregnancies progressing to 42 weeks or beyond(BMC, 2021-05-25)BACKGROUND: Post-term gestation beyond 41+6 completed weeks of gestation is known to be associated with a sharp increase in the risk of stillbirth and perinatal mortality. However, the risk of common adverse outcomes related to labour, such as shoulder dystocia and post-partum haemorrhage for those delivering at this advanced gestation, remains poorly characterised. The objective of this study was to examine the risk of adverse, labour-related outcomes for women progressing to 42 weeks gestation or beyond, compared with those giving birth at 39 completed weeks. METHODS: We performed a state-wide cohort study using routinely collected perinatal data in Australia. Comparing the two gestation cohorts, we examined the adjusted relative risk of clinically significant labour-related adverse outcomes, including macrosomia (≥ 4500 at birth), post-partum haemorrhage (≥1000 ml), shoulder dystocia, 3rd or 4th degree perineal tear and unplanned caesarean section. Parity, maternal age and mode of birth were adjusted for using logistic regression. RESULTS: The study cohort included 91,314 women who birthed at 39 completed weeks and 4317 at ≥42 completed weeks. Compared to 39 weeks gestation, those giving birth ≥42 weeks gestation had an adjusted relative risk (aRR) of 1.85 (95% CI 1.55-2.20) for post-partum haemorrhage following vaginal birth, 2.29 (95% CI 1.89-2.78) following instrumental birth and 1.44 (95% CI 1.17-1.78) following emergency caesarean section; 1.43 (95% CI 1.16-1.77) for shoulder dystocia (for non-macrosomic babies); and 1.22 (95% CI 1.03-1.45) for 3rd or 4th degree perineal tear (all women). The adjusted relative risk of giving birth to a macrosomic baby was 10.19 (95% CI 8.26-12.57) among nulliparous women and 4.71 (95% CI 3.90-5.68) among multiparous women. The risk of unplanned caesarean section was 1.96 (95% CI 1.86-2.06) following any labour and 1.47 (95% CI 1.38-1.56) following induction of labour. CONCLUSIONS: Giving birth at ≥42 weeks gestation may be an under-recognised risk factor for several important, labour-related adverse outcomes. Clinicians should be aware that labour at this advanced gestation incurs a higher risk of adverse outcomes. In addition to known perinatal risks, the risk of obstetric complications should be considered in the counselling of women labouring at post-term gestation.
-
ItemIdentification of the optimal growth charts for use in a preterm population: An Australian state-wide retrospective cohort study(PUBLIC LIBRARY SCIENCE, 2019-10)BACKGROUND: Preterm infants are a group at high risk of having experienced placental insufficiency. It is unclear which growth charts perform best in identifying infants at increased risk of stillbirth and other adverse perinatal outcomes. We compared 2 birthweight charts (population centiles and INTERGROWTH-21st birthweight centiles) and 3 fetal growth charts (INTERGROWTH-21st fetal growth charts, World Health Organization fetal growth charts, and Gestation Related Optimal Weight [GROW] customised growth charts) to identify which chart performed best in identifying infants at increased risk of adverse perinatal outcome in a preterm population. METHODS AND FINDINGS: We conducted a retrospective cohort study of all preterm infants born at 24.0 to 36.9 weeks gestation in Victoria, Australia, from 2005 to 2015 (28,968 records available for analysis). All above growth charts were applied to the population. Proportions classified as <5th centile and <10th centile by each chart were compared, as were proportions of stillborn infants considered small for gestational age (SGA, <10th centile) by each chart. We then compared the relative performance of non-overlapping SGA cohorts by each chart to our low-risk reference population (infants born appropriate size for gestational age [>10th and <90th centile] by all intrauterine charts [AGAall]) for the following perinatal outcomes: stillbirth, perinatal mortality (stillbirth or neonatal death), Apgar <4 or <7 at 5 minutes, neonatal intensive care unit admissions, suspicion of poor fetal growth leading to expedited delivery, and cesarean section. All intrauterine charts classified a greater proportion of infants as <5th or <10th centile than birthweight charts. The magnitude of the difference between birthweight and fetal charts was greater at more preterm gestations. Of the fetal charts, GROW customised charts classified the greatest number of infants as SGA (22.3%) and the greatest number of stillborn infants as SGA (57%). INTERGROWTH classified almost no additional infants as SGA that were not already considered SGA on GROW or WHO charts; however, those infants classified as SGA by INTERGROWTH had the greatest risk of both stillbirth and total perinatal mortality. GROW customised charts classified a larger proportion of infants as SGA, and these infants were still at increased risk of mortality and adverse perinatal outcomes compared to the AGAall population. Consistent with similar studies in this field, our study was limited in comparing growth charts by the degree of overlap, with many infants classified as SGA by multiple charts. We attempted to overcome this by examining and comparing sub-populations classified as SGA by only 1 growth chart. CONCLUSIONS: In this study, fetal charts classified greater proportions of preterm and stillborn infants as SGA, which more accurately reflected true fetal growth restriction. Of the intrauterine charts, INTERGROWTH classified the smallest number of preterm infants as SGA, although it identified a particularly high-risk cohort, and GROW customised charts classified the greatest number at increased risk of perinatal mortality.