Papers by Laura Schummers
Journal of Obstetrics and Gynaecology Canada
New England Journal of Medicine, 2022
International Journal of Population Data Science
BackgroundThe shifting landscape of abortion care from a hospital-only to a distributed service i... more BackgroundThe shifting landscape of abortion care from a hospital-only to a distributed service including primary care has implications for how to identify abortion cohorts for research and surveillance. The objectives of this study were to 1) create an improved approach to define abortion cohorts using linked administrative data sets and 2) evaluate the performance of this approach for abortion surveillance compared with standard approaches. MethodsWe applied four principles to identify induced abortion cohorts when some services are delivered beyond hospital settings; 1) exclude early pregnancy losses and postpartum procedures; 2) use multiple data sources; 3) define episodes of care; 4) apply a hierarchical algorithm to determine abortion date to a population-based cohort of all abortion events in Ontario (Canada) from January 1, 2018-March 15, 2020. We calculated risk differences (RD, with 95% confidence intervals) comparing the proportion of medication vs. surgical, first vs. s...
Table S1. Self-identified maternal and paternal race (nâ =â 2700). Table S2. Socio-demographic ch... more Table S1. Self-identified maternal and paternal race (nâ =â 2700). Table S2. Socio-demographic characteristics of samples, compared to national statistics. Table S3. Mistreatment, stratified by self-identified race of woman and partner. Table S4. Mistreatment, stratified by immigration status. Table S5. Mistreatment, stratified by maternal age at birth. Table S6 Mistreatment, stratified by parity. Table S7. Mistreatment, stratified by labour induction and mode of birth. Table S8. Mistreatment, stratified by newborn health problems. Table S9. Mistreatment indicators, stratified by disarticulation between women and providers.
Presents the observed and optimism-correct area under the receiver-operator characteristic curve ... more Presents the observed and optimism-correct area under the receiver-operator characteristic curve for risk prediction models built for 12 pregnancy and birth outcomes, and provides a complete list of included predictors for each model. (DOCX 30 kb)
Presents all model performance measures for each of the 120 models built using data augmented wit... more Presents all model performance measures for each of the 120 models built using data augmented with simulated predictors. Performance measures include the area under the receiver-operator characteristic curve, the proportion of the population classified into a clinically distinct risk group, the proportion of the population with an informative likelihood ratio, and Nagelkerkeâ s r2. (DOCX 47 kb)
with less favourable attitudes to home birth. Among all providers, favourability scores were link... more with less favourable attitudes to home birth. Among all providers, favourability scores were linked to beliefs about
Paediatric and Perinatal Epidemiology
BACKGROUND Estimation of causal effects of short interpregnancy interval on pregnancy outcomes ma... more BACKGROUND Estimation of causal effects of short interpregnancy interval on pregnancy outcomes may be confounded by time-varying factors. These confounders should be ascertained at or before delivery of the first ("index") pregnancy, but are often only measured at the subsequent pregnancy. OBJECTIVES To quantify bias induced by adjusting for time-varying confounders ascertained at the subsequent (rather than the index) pregnancy in estimated effects of short interpregnancy interval on pregnancy outcomes. METHODS We analysed linked records for births in British Columbia, Canada, 2004-2014, to women with ≥2 singleton pregnancies (n = 121 151). We used log binomial regression to compare short (<6, 6-11, 12-17 months) to 18-23-month reference intervals for 5 outcomes: perinatal mortality (stillbirth and neonatal death); small for gestational age (SGA) birth and preterm delivery (all, early, spontaneous). We calculated per cent differences between adjusted risk ratios (aRR) from two models with maternal age, low socio-economic status, body mass index, and smoking ascertained in the index pregnancy and the subsequent pregnancy. We considered relative per cent differences <5% minimal, 5%-9% modest, and ≥10% substantial. RESULTS Adjustment for confounders measured at the subsequent pregnancy introduced modest bias towards the null for perinatal mortality aRRs for <6-month interpregnancy intervals [-9.7%, 95% confidence interval [CI] -15.3, -6.2). SGA aRRs were minimally biased towards the null (-1.1%, 95% CI -2.6, 0.8) for <6-month intervals. While early preterm delivery aRRs were substantially biased towards the null (-10.4%, 95% CI -14.0, -6.6) for <6-month interpregnancy intervals, bias was minimal for <6-month intervals for all preterm deliveries (-0.6%, 95% CI -2.0, 0.8) and spontaneous preterm deliveries (-1.3%, 95% CI -3.1, 0.1). For all outcomes, bias was attenuated and minimal for 6-11-month and 12-17-month interpregnancy intervals. CONCLUSION These findings suggest that maternally linked pregnancy data may not be needed for appropriate confounder adjustment when studying the effects of short interpregnancy interval on pregnancy outcomes.
Paediatric and perinatal epidemiology, 2020
BACKGROUND Estimation of causal effects of short interpregnancy interval on pregnancy outcomes ma... more BACKGROUND Estimation of causal effects of short interpregnancy interval on pregnancy outcomes may be confounded by time-varying factors. These confounders should be ascertained at or before delivery of the first ("index") pregnancy, but are often only measured at the subsequent pregnancy. OBJECTIVES To quantify bias induced by adjusting for time-varying confounders ascertained at the subsequent (rather than the index) pregnancy in estimated effects of short interpregnancy interval on pregnancy outcomes. METHODS We analysed linked records for births in British Columbia, Canada, 2004-2014, to women with ≥2 singleton pregnancies (n = 121 151). We used log binomial regression to compare short (<6, 6-11, 12-17 months) to 18-23-month reference intervals for 5 outcomes: perinatal mortality (stillbirth and neonatal death); small for gestational age (SGA) birth and preterm delivery (all, early, spontaneous). We calculated per cent differences between adjusted risk ratios (aRR) ...
Paediatric and perinatal epidemiology, 2021
CMAJ Open
Background: Ulipristal acetate 30 mg became available as prescription-only emergency contraceptio... more Background: Ulipristal acetate 30 mg became available as prescription-only emergency contraception in British Columbia, Canada, in September 2015, as an addition to over-the-counter levonorgestrel emergency contraception. In this study, we determined dispensing and practice use patterns for ulipristal acetate, as well as facilitators of and barriers to emergency contraception for physicians, pharmacists and patients in BC. Methods: In the quantitative component of this mixed-methods study, we examined ulipristal acetate use from September 2015 to December 2018 using a database that captures all outpatient prescription dispensations in BC (PharmaNet) and another capturing market sales numbers for all oral emergency contraception in BC (IQVIA). We analyzed the quantitative data descriptively. We conducted semistructured interviews from August to November 2019, exploring barriers and facilitators affecting the use of ulipristal acetate. We performed iterative qualitative data collection and thematic analysis guided by Michie’s Theoretical Domains Framework. Results: Over the 3-year study period, 318 patients filled 368 prescriptions for ulipristal acetate. Use of this agent increased between 2015 and 2018. However, levonorgestrel use by sales (range 118 897–129 478 units/yr) was substantially higher than use of ulipristal acetate (range 128–389 units/yr). In the 39 interviews we conducted, from the perspectives of 12 patients, 12 community pharmacists, and 15 prescribers, we identified the following themes and respective theoretical domains as barriers to access: low awareness of ulipristal acetate (knowledge), beliefs and experiences related to shame and stigma (beliefs about consequences), and multiple health system barriers (reinforcement). Interpretation: Use of ulipristal acetate in BC was low compared with use of levonorgestrel emergency contraception; lack of knowledge, beliefs about consequences and health system barriers may be important impediments to expanding use of ulipristal acetate. These findings illuminate potential factors to explain low use of this agent and point to the need for additional strategies to support implementation.
ABSTRACT Background: Fetal health assessment aims to identify fetuses at risk for stillbirth or n... more ABSTRACT Background: Fetal health assessment aims to identify fetuses at risk for stillbirth or neonatal mortality but the poor validity of the current tests can lead to iatrogenic intervention. Most tests are high-technology, which limits their use in low resources settings. In 2009, an NIH committee identified the need for innovation in antenatal testing, with specific attention toward fetal movement assessments and novel combinations of test results. Methods: Our team piloted two innovative combined tests: 1) Movement and Pulse index (MAPi), a clinical prediction model that uses appropriate statistical methods to combine novel and extant indicators of fetal well-being and 2) MobileMAPi, a low-cost, low-technology model for use in low-resource settings. We studied pregnant women receiving standard antenatal testing (NST: Non-Stress Test, AFI: Amniotic Fluid Index), and added a newly developed Fetal Movement and Behavior Log and the Auscultated Acceleration Test (AAT), a low-technology test developed in 1986 by midwives as an innovation in low-technology fetal assessment. Results: 51 participants were recruited into our pilot study, for a total of 194 AATs, 97 NSTs, and 55 AFIs performed, and 260 completed Fetal Behavior and Movement Logs. The rate of neonatal morbidity was 5.3%, and the rate of cesarean delivery was 34.2%. Pilot results confirmed feasibility for combining parameters from each assessment modality to develop MAPi and MobileMAPi, and will inform our subsequent research in this area. Conclusion: Mapi and MobileMAPi are innovations that could reduce stillbirth rates and maternal-newborn morbidity, and enhance the availability of fetal surveillance methods in low-resource settings.
Journal of Obstetrics and Gynaecology Canada
Objectives Canadian policy allowing mifepristone medication abortion without regulations limiting... more Objectives Canadian policy allowing mifepristone medication abortion without regulations limiting practice is globally unique. The objective of this study was to examine the impact of Canadian deregulated medication abortion policy on abortion utilization and complications. Methods We used linked administrative data (billing, hospital, ambulatory care, and prescription records) from Ontario to examine the 306,750 surgical and medication abortions from January 2012 to December 2019. We examined medication abortion utilization, second trimester abortion, abortion-related complications (infection, hemorrhage, embolism, shock, damage to pelvic organs, other venous complications), surgical follow-up (laparotomy, laparoscopy, hysterectomy), aspiration/re-aspiration, and ongoing pregnancy within 6 weeks of the abortion. We compared incidences before and after mifepristone deregulation (2012-2016 vs. 2018-2019). Results Medication abortion utilization increased substantially from 2.4% of all abortions from 2012-2016 to 30.9% in 2018-2019. Second trimester abortion decreased from 6.0% [95% CI 5.7-6.2] before to 5.3% [5.2-5.5] after mifepristone deregulation. Among the 289,013 first trimester abortions, complications were similar before and after deregulation: abortion-related complication incidence was 0.65% [0.62-0.69] before and 0.60% [0.55-0.66] after. Surgical follow-up was similar in both periods, occurring in 0.05% [0.04-0.06] before and 0.05% [0.04-0.07] after deregulation. Aspiration/re-aspiration increased modestly from 0.05% [0.04-0.06] to 0.12% [0.09-0.14], as did ectopic pregnancy diagnosed after the abortion, from 0.15% [0.13-0.17] to 0.22% [0.19-0.26]. Ongoing intrauterine pregnancy continuing to delivery increased from 0.07% [0.06-0.09] to 0.30% [0.27-0.35], while ongoing pregnancy continuing to subsequent abortion increased from 0.94% [0.90-0.99] to 1.49% [1.40-1.58]. Conclusions Canada's globally unique deregulation of mifepristone medication abortion substantially increased medication abortion utilization and was not associated with a clinically significant increase in abortion complications or ongoing pregnancy.
Systematic Reviews
Background Early pregnancy loss (unintended pregnancy loss before 20 completed weeks of gestation... more Background Early pregnancy loss (unintended pregnancy loss before 20 completed weeks of gestation) is a common adverse pregnancy outcome, with previous evidence reporting incidence ranging from 10 to 30% of detected pregnancies. The objective of this systematic review and meta-analysis is to determine the incidence and range of early pregnancy loss in contemporary pregnant populations based on studies with good internal and external validity. Findings may be useful for clinical counseling in pre-conception and family planning settings and for people who experience early pregnancy loss. Methods We will search MEDLINE, EMBASE, and CINAHL databases using combinations of medical subject headings and keywords. Peer-reviewed, full-text original research articles that meet the following criteria will be included: (1) human study; (2) study designs: controlled clinical trials or observational studies with at least 100 pregnancies in the denominator, or systematic reviews of studies using th...
Obstetrics & Gynecology
Risks of adverse outcomes in planned home and birth center births were similar; overall, perinata... more Risks of adverse outcomes in planned home and birth center births were similar; overall, perinatal outcomes were comparable with international settings.
Journal of Obstetrics and Gynaecology Canada
Objectives To compare the current dispensing patterns of ulipristal acetate emergency contracepti... more Objectives To compare the current dispensing patterns of ulipristal acetate emergency contraception (UPA-EC) to levonorgestrel emergency contraception (LNG-EC) since UPA-EC became available in British Columbia (BC) in 2015, using sales and prescription dispensation as a proxy for actual use, and to explore the facilitators and barriers to UPA-EC use perceived by prescribers and patients in BC. Methods Mixed methods involving descriptive analysis of (a) BC sales numbers of LNG-EC and UPA-EC between 09/2015 and 12/2018 and (b) UPA-EC prescriptions filled. We also conducted an interview study with BC prescribers and patients to explore individual and environmental barriers and facilitators that impact UPA-EC use. We used Michie's Theoretical Domains Framework to identify implementation factors, and support the development of evidence-informed recommendations to enhance EC access. Results Quantitative data of UPA-EC sales increased from 44 units in 2015/2016 to 389 units in 2018. In contrast, sales of LNG-EC units appear to stay the same. Our qualitative analysis of interviews with 15 prescribers and 12 patients identified key implementation factors: (a) lack of knowledge of UPA-EC (b) stigma associated with accessing, EC and (c) logistical and financial barriers. Conclusions The quantitative data supports the hypothesis that UPA-EC sales are lower than LNG-EC but have increased over time. When increasing knowledge about UPA-EC, destigmatizing and normalizing EC as a form of coital dependant contraception is important to reframe how we think about improving access to EC.
Journal of Obstetrics and Gynaecology Canada
Objectives There is little evidence available to support pregnancy spacing decisions after a peri... more Objectives There is little evidence available to support pregnancy spacing decisions after a perinatal loss. The objective of this study was to examine whether short interpregnancy intervals after a perinatal loss are associated with increased risks of adverse outcomes in the subsequent pregnancy. Methods We analyzed all pregnancies from 2004–2014 to women with ≥2 singleton pregnancies, with the first resulting in a stillbirth or late termination at (≥20 weeks) or a neonatal death. According to interpregnancy interval, we examined risks in the subsequent pregnancy of small-for-gestational-age, adverse fetal-infant composite (stillbirth, neonatal death, Results Of 148,544 interpregnancy intervals in the study period, the study sample included 2,041 pregnancies, 1,626 following a stillbirth/late termination and 405 following a neonatal death. Risks of most outcomes were not increased at short ( Conclusions After a perinatal loss, short interpregnancy interval was associated with increased risk of spontaneous preterm delivery, but not other adverse pregnancy outcomes.
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Papers by Laura Schummers