Obstetrics and Gynaecology - Research Publications

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    Risk of obstetric anal sphincter injury among women who birth vaginally after a prior caesarean section: A state-wide cohort study
    Uebergang, J ; Hiscock, R ; Hastie, R ; Middleton, A ; Pritchard, N ; Walker, S ; Tong, S ; Lindquist, A (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 However, prior studies have been small or have used outdated methodology.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.
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    Developmental Outcomes for Children After Elective Birth at 39 Weeks' Gestation
    Lindquist, A ; Hastie, R ; Kennedy, A ; Gurrin, L ; Middleton, A ; Quach, J ; Cheong, J ; Walker, SP ; Hiscock, R ; Tong, S (AMER MEDICAL ASSOC, 2022-07)
    IMPORTANCE: Elective births at 39 weeks' gestation are increasing. While this option may improve maternal and perinatal outcomes compared with expectant management, longer-term childhood developmental outcomes are uncertain. OBJECTIVE: To investigate the association between elective birth at 39 weeks' gestation and the risk of childhood developmental vulnerability. DESIGN, SETTING, AND PARTICIPANTS: For this cohort study, 2 causal inference analyses were conducted using Australian statewide, population-based data. Perinatal data from births between January 1, 2005, and December 31, 2013, were linked to childhood developmental outcomes at age 4 to 6 years (assessed using multiple imputation via inverse probability-weighted regression adjustment). Data analyses were conducted between September 7 and November 9, 2021. EXPOSURES: Two exposure groups were considered: (1) elective birth between 39 weeks and 0 days' and 39 weeks and 6 days' gestation vs expectant management and (2) birth via induction of labor vs planned cesarean delivery among those born electively at 39 weeks' gestation. MAIN OUTCOMES AND MEASURES: Childhood developmental vulnerability at school entry, defined as scoring below the 10th percentile in at least 2 of 5 developmental domains (physical health and well-being, social competence, emotional maturity, school-based language and cognitive skills, and communication skills and general knowledge). RESULTS: Of 176 236 births with linked outcome data, 88 165 met the inclusion criteria. Among these, 15 927 (18.1%) were elective births at 39 weeks' gestation (induction of labor or planned cesarean delivery), and 72 238 (81.9%) were expectantly managed with subsequent birth between 40 and 43 weeks' gestation. Compared with expectant management, elective birth at 39 weeks' gestation was not associated with an altered risk of childhood global developmental vulnerability (adjusted relative risk [aRR], 1.03; 95% CI, 0.96-1.12) or with developmental vulnerability in any of the individual domains. In an analysis restricted to elective births at 39 weeks' gestation, induction of labor (n = 7928) compared with planned cesarean delivery (n = 7999) was not associated with childhood developmental vulnerability (aRR, 0.96; 95% CI, 0.82-1.12) or with vulnerability in any individual domains. CONCLUSIONS AND RELEVANCE: In this cohort study, elective birth at 39 weeks' gestation was not associated with childhood developmental vulnerability. For those born electively at 39 weeks' gestation, birth after induction of labor or by elective cesarean delivery had similar developmental outcomes.
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    Incidence and causes of stillbirth in the only tertiary referral hospital in the Solomon Islands: a hospital-based retrospective cohort study
    De Silva, MS ; Panisi, L ; Manubuasa, L ; Honimae, C ; Taragwanu, S ; Burggraaf, S ; Ogaoga, D ; Lindquist, AC ; Walker, SP ; Tong, S ; Hastie, R (BMJ PUBLISHING GROUP, 2022-12)
    OBJECTIVES: Stillbirth is a major global health issue, which disproportionately affects families living in low-income and middle-income countries. The Solomon Islands is a Pacific nation with poor perinatal outcomes, however research investigating stillbirth is lacking. Thus, we aimed to investigate the incidence and cause of stillbirth occurring at the National Referral Hospital, Solomon Islands. DESIGN: We conducted a retrospective cohort study from January 2017 to December 2018. SETTING: At the only tertiary referral hospital in the Solomon Islands, on the main island of Guadalcanal. PARTICIPANTS: All births occurring in the hospital during the study period. OUTCOME MEASURES: Number of, causes and risk factors for stillbirths (fetal deaths before birth at ≥20 estimated gestational weeks, or ≥500 g in birth weight). RESULTS: Over 2 years 341 stillbirths and 11 056 total births were recorded, giving an institutional incidence of 31 stillbirths per 1000 births. Of the cases with a recorded cause of death, 72% were deemed preventable. Most stillbirths occurred antenatally and 62% at preterm gestations (<37 weeks). 59% had a birth weight below 2500 g and preventable maternal conditions were present in 42% of the cases. 46% of the cases were caused by an acute intrapartum event, and among these 92% did not receive intrapartum monitoring. CONCLUSIONS: Stillbirth affects 31 in every 1000 births at the National Referral Hospital in the Solomon Islands and many cases are preventable. Our findings highlight the urgent need for increased focus on perinatal deaths in the Solomon Islands with universal classification and targeted training, improved quality of obstetrical care and community awareness.
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    Time to resolution of tubal ectopic pregnancy following methotrexate treatment: A retrospective cohort study
    Davenport, MJ ; Lindquist, A ; Brownfoot, F ; Pritchard, N ; Tong, S ; Hastie, R ; Garzon, S (PUBLIC LIBRARY SCIENCE, 2022-05-24)
    OBJECTIVE: To determine the time to resolution of tubal ectopic pregnancy after methotrexate treatment. METHODS: A 14-year retrospective cohort study was performed from 2004-2018 and assessed 216 women treated with single-dose methotrexate for tubal ectopic pregnancy. Women were treated using a single-dose protocol of intramuscular methotrexate (50mg/m2) for confirmed tubal ectopic pregnancy on ultrasound. Ectopic pregnancies were included if the ectopic pregnancy mass was <35mm, no evidence of rupture and no embryonic cardiac activity. Serum hCG was measured on day 1, 4 and 7 of treatment and then at standard weekly intervals until resolution. Where there was not a ≥15% decline in hCG from day 4 and day 7, a second dose of methotrexate was administered. The primary outcome was time to resolution (days), with serum hCG <5 IU/L considered resolved. The secondary outcome was need for rescue surgery. RESULTS: Among women who did not proceed to surgery, the median time to resolution was 22 days (IQR 14,34). Time to resolution and need for rescue surgery increased with baseline hCG. When hCG was <1000 IU/L, the median was 20 days (IQR 13,29) but 34.5 days (IQR 22,48) with hCG >2000 IU/L. Early hCG trends were predictive of time to resolution and likelihood of rescue surgery; a hCG rise of >1000 IU/L between Days 1-4 increased time to resolution to 61 days (IQR 35,80) and an odds ratio of rescue surgery of 28.6 (95% C.I. 5.3,155.4). CONCLUSION: The median time to resolution for ectopic pregnancies treated with methotrexate is 22 days and associated with baseline hCG levels. The predictive value of baseline hCG may be useful in clinical decision making and counselling women considering methotrexate for ectopic pregnancy.
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    Low-Dose Aspirin for Preventing Birth of a Small-For-Gestational Age Neonate in a Subsequent Pregnancy
    Hastie, R ; Tong, S ; Wikstrom, A-K ; Walker, SP ; Lindquist, A ; Cluver, CA ; Kupka, E ; Bergman, L ; Hesselman, S (LIPPINCOTT WILLIAMS & WILKINS, 2022-04)
    OBJECTIVE: To estimate whether low-dose aspirin use is associated with an altered risk of delivering a small-for-gestational age (SGA) neonate among women with a history of having an SGA neonate in a prior pregnancy. METHODS: We performed a Swedish register-based cohort study including women in their second pregnancy who had a history of having an SGA neonate (birth weight less than the 10th percentile). The association between use of low-dose aspirin in subsequent pregnancy and birth of an SGA neonate or a severely SGA neonate (birth weight less than the third percentile) were estimated using inverse propensity-weighted estimation, accounting for potential confounders. RESULTS: Among 8,416 women who gave birth to an SGA neonate in their first pregnancy, 801 (9.5%) used low-dose aspirin during their second pregnancy. The incidence of SGA neonates was similar among women using low-dose aspirin (21.7%) and those who did not use aspirin (20.7%). Low-dose aspirin use in pregnancy was not associated with an altered risk of having an SGA neonate (adjusted relative risk [aRR] 0.86, 95% CI 0.67-1.10) or a severely SGA neonate (aRR 0.98, 95% CI 0.71-1.34). Given the strong association between preeclampsia and SGA, we performed subgroup analyses based on preeclampsia status. Among women who had an SGA neonate and co-existing preeclampsia in their first pregnancy, low-dose aspirin was not associated with an altered risk of having an SGA (aRR 0.83, 95% CI 0.63-1.10) or severely SGA (aRR 1.02, 95% CI 0.73-1.44) neonate. Additionally, no association was seen among women who developed preeclampsia in their second pregnancy. CONCLUSION: Among women with a history of having an SGA neonate, low-dose aspirin was not associated with a decreased risk of having an SGA or severely SGA neonate in subsequent pregnancy. These findings suggest that low-dose aspirin should not be used to prevent recurrent SGA.
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    Maternal lithium use and the risk of adverse pregnancy and neonatal outcomes: a Swedish population-based cohort study
    Hastie, R ; Tong, S ; Hiscock, R ; Lindquist, A ; Lindstroem, L ; Wikstroem, A-K ; Sundstroem-Poromaa, I (BMC, 2021-12-02)
    BACKGROUND: Lithium is prescribed during pregnancy, but there is limited information about pregnancy and neonatal outcomes following in utero exposure. Thus, this study aimed to investigate the associations between lithium use and adverse pregnancy and neonatal outcomes. METHODS: This population-based cohort study examined associations between maternal lithium use and major adverse pregnancy and neonatal outcomes via inverse probability weighted propensity score regression models. RESULTS: Of 854,017 women included in this study, 434 (0.05%) used lithium during pregnancy. Among pre-specified primary outcomes, lithium use during pregnancy was associated with an increased risk of spontaneous preterm birth (8.7% vs 3.0%; adjusted relative risk [aRR] 2.64 95% CI 1.82, 3.82) and birth of a large for gestational age infant (9.0% vs 3.5%; aRR 2.64 95% CI 1.91, 3.66), but not preeclampsia nor birth of a small for gestational age infant. Among secondary outcomes, lithium use was associated with an increased risk of cardiac malformations (2.1% vs 0.8%; aRR 3.17 95% CI 1.64, 6.13). In an analysis restricted to pregnant women with a diagnosed psychiatric illness (n=9552), associations remained between lithium and spontaneous preterm birth, birth of a large for gestational age infant, and cardiovascular malformations; and a positive association with neonatal hypoglycaemia was also found. These associations were also apparent in a further analysis comparing women who continued lithium treatment during pregnancy to those who discontinued prior to pregnancy. CONCLUSIONS: Lithium use during pregnancy is associated with an increased risk of spontaneous preterm birth and other adverse neonatal outcomes. These potential risks must be balanced against the important benefit of treatment and should be used to guide shared decision-making.
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    Severe maternal morbidity in the Asia Pacific: a systematic review and meta-analysis
    De Silva, M ; Panisi, L ; Lindquist, A ; Cluver, C ; Middleton, A ; Koete, B ; Vogel, JP ; Walker, S ; Tong, S ; Hastie, R (ELSEVIER, 2021-09)
    BACKGROUND: Monitoring rates of severe maternal morbidity (such as eclampsia and uterine rupture) is useful to assess the quality of obstetric care, particularly in low and lower-middle-income countries (LMICs). METHODS: We undertook a systematic review characterising the proportion and causes of severe maternal morbidity in the Asia Pacific region. We searched Medline, Embase, Cochrane CENTRAL library and the World Health Organization Western Pacific Index database for studies in the Asia-Pacific reporting maternal morbidity/near miss using a predefined search strategy. We included cohort, case-control and cross-sectional studies published in English before September 2020. A meta-analysis was performed calculating the overall proportion of near miss events by sub-region, country, near miss definition, economic status, setting and cause using a random-effects model. FINDINGS: We identified 26,232 articles, screened 24,306 and retrieved 454 full text articles. Of these, 197 studies spanning 27 countries were included. 13 countries in the region were not represented. There were 30,183,608 pregnancies and 100,011 near misses included. The total proportion of near miss events was 4•4 (95% CI 4•3-4•5) per 1000 total births. The greatest proportion of near misses were found in the Western Pacific region (around Papua New Guinea) at 11•8 per 1000 births (95% CI 6•6-17•1; I2 96.05%). Low-income countries displayed the greatest proportion of near misses (13•4, 95% CI 6•0-20•7), followed by lower-middle income countries (11•1; 95% CI 10•4 - 11•9). High-income countries had the lowest proportion (2•2, 95% CI 2•1-2•3). Postpartum haemorrhage was the most common near miss event (5•9, 95% CI 4•5-7•2), followed by eclampsia (2•7, 95% CI 2•4 - 2•9). INTERPRETATION: There is a high burden of severe maternal morbidity in the Asia-Pacific. LMICs are disproportionately affected. Most of the common causes are preventable. This provides an opportunity to implement targeted interventions which could have major clinical impact.
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    Maternal mortality at the National Referral Hospital in Honiara, Solomon Islands over a five-year period
    De Silva, M ; Panisi, L ; Maepioh, A ; Mitchell, R ; Lindquist, A ; Tong, S ; Hastie, R (WILEY, 2020-04)
    BACKGROUND: The Solomon Islands is a developing country facing significant barriers to the provision of quality antenatal and obstetric care. The maternal mortality rate is 114/100 000 live births, ranking the Solomon Islands 113th globally. Investigating maternal mortality may yield valuable insight into improving these numbers. AIM: The objective of this study was to review all cases of maternal mortality at the National Referral Hospital, Solomon Islands over a five-year period. MATERIALS AND METHODS: This was a retrospective review of maternal deaths occurring at the National Referral Hospital, Solomon Islands from 2013 to 2017. Data on maternal demographics, characteristics and cause of death were collected. RESULTS: There were 39 maternal deaths at the National Referral Hospital from 2013 to 2017. The maternal mortality rate of the National Referral Hospital (139/100 000) is higher than the national rate (114/100 000). Most deaths were direct, with 28% attributed to haemorrhage. Overall, 79% of the total maternal deaths had elements that may be considered preventable, with laboratory delays present in 54% and medication shortages present in 29% of cases. CONCLUSION: Maternal mortality is high in the Solomon Islands, with many potentially preventable deaths occurring at the National Referral Hospital. Continued focus on improving data collection, access to resources, and training is vital to reduce maternal mortality in the Solomon Islands.
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    Risk of major labour-related complications for pregnancies progressing to 42 weeks or beyond
    Lindquist, AC ; Hastie, RM ; Hiscock, RJ ; Pritchard, NL ; Walker, SP ; Tong, S (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.
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    Preventable stillbirths in the Solomon Islands - A hidden tragedy
    De Silva, M ; Panisi, L ; Manubuasa, L ; Honimae, C ; Taragwanu, S ; Burggraaf, S ; Ogaoga, D ; Lindquist, A ; Walker, S ; Tong, S ; Hastie, R (ELSEVIER, 2020-12)