Inequalities in access to prenatal care during the COVID-19 pandemic: Analysis of a population-based cohort.

BACKGROUND: Before the COVID-19 pandemic, access to prenatal care was lower among some socio-demographic groups. This pandemic caused disruptions to routine preventative care, which could have increased inequalities. OBJECTIVES: To investigate if the COVID-19 pandemic increased inequalities in access to prenatal care among those who are younger, live in rural areas, have a lower socio-economic situation (SES) and are recent immigrants. METHODS: We used linked administrative datasets from ICES to identify a population-based cohort of 455,245 deliveries in Ontario from January 2018 to December 2021. Our outcomes were first-trimester prenatal visits, first-trimester ultrasound and adequacy of prenatal care. We used joinpoint analysis to examine outcome time trends and identify trend change points. We stratified analyses by age, rural residence, SES and recent immigration, and examined risk differences (RD) with 95% confidence intervals (CI) between groups at the beginning and end of the study period. RESULTS: For all outcomes, we noted disruptions to care beginning in March or April 2020 and returning to previous trends by November 2020. Inequalities were stable across groups, except recent immigrants. In July 2017, 65.0% and 69.8% of recent immigrants and non-immigrants, respectively, received ultrasounds in the first trimester (RD -4.8%, 95% CI -8.0, -1.5). By October 2020, this had increased to 75.4%, with no difference with non-immigrants (RD 0.4%, 95% CI -2.4, 3.2). Adequacy of prenatal care showed more intensive care as of November 2020, reflecting a higher number of visits. CONCLUSIONS: We found no evidence that inequalities between socio-economic groups that existed prior to the pandemic worsened after March 2020. The pandemic may be associated with increased access to care for recent immigrants. The introduction of virtual visits may have resulted in a higher number of prenatal care visits.

Travel Time to Delivery, Antenatal Care, and Birth Outcomes: A Population-Based Cohort of Uncomplicated Pregnancies in British Columbia, 2012-2019.

OBJECTIVE: Health policy and system leaders need to know whether long travel time to a delivery facility adversely affects birth outcomes. In this study, we estimated associations between travel time to delivery and outcomes in low-risk pregnancies. METHODS: This population-based cohort included all singleton births without obstetric comorbidities or intrapartum facility transfers in British Columbia, Canada, from 2012 to 2019. Travel time was measured from maternal residential postal code to delivery facility using road network analysis. We estimated associations between travel time and severe maternal morbidity, stillbirth, pre-term birth, and small-for-gestational age (SGA) and large-for-gestational age (LGA) status using logistic regression, adjusted for confounders (adjusted odds ratios [aORs]). To examine variations in associations between travel time and outcomes by antenatal care utilization, we stratified models by antenatal care categories. RESULTS: Of 232 698 births, 3.8% occurred at a facility ≥60 minutes from the maternal residence. Obesity, adolescent age, substance use, inadequate prenatal care, and low socioeconomic status were more frequent among those traveling farther for delivery. Travel time ≥120 minutes was associated with increased risk of stillbirth (aOR 1.8; 95% CI 1.2-2.8), pre-term birth (aOR 2.3; 95% CI 2.1-2.5), LGA (aOR 1.5; 95% CI 1.4-1.6), and severe maternal morbidity (aOR 1.5; 95% CI 1.2-1.8), but not SGA (aOR 1.0; 95% CI 0.8-1.1), when compared with a travel time of 1-29 minutes. Risk of stillbirth was greatest with inadequate and intensive (adequate plus) antenatal care but persisted for severe maternal morbidity, pre-term birth, and LGA across categories. CONCLUSION: Longer travel time to delivery was associated with increased risk of adverse outcomes in low-risk pregnancies after adjusting for confounding factors. Associations were stronger among those with inadequate antenatal care.

A more accurate approach to define abortion cohorts using linked administrative data: an application to Ontario, Canada.

Background: The 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. Methods: We 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. second trimester, and complication incidence applying these principles vs. standard approaches. Results: Hospital-only data (versus multiple data sources) underestimated the frequency of medication abortion (16.1% vs. 31.4%; RD -15.3% [-14.3, -16.3]) and first-trimester abortion (82.1% vs. 94.5%; RD -12.8 [-11.4, 13.4]) and overestimated incidence of abortion complication (2.9% vs. 0.69%; RD 2.2% [1.8, 2.7]). An unlinked (versus linked) approach underestimated the frequency of abortion complications (0.19% vs 0.69%, -RD 0.50% [-0.44--0.56]). Including (versus excluding) abortions following early pregnancy loss or delivery events increased the estimated incidence of abortion complications (1.29% vs. 0.69%, RD 0.60% [0.51-0.69]. Conclusion: New methods are required to accurately identify abortion cohorts for surveillance or research. When legal or regulatory approaches to medication abortion evolve to enable abortion in primary care or office-based settings, hospital-based surveillance systems will become incomplete and biased; to continue valid and complete abortion surveillance, methods must be adjusted to ensure complete capture of procedures across all settings.

Abortion Safety and Use with Normally Prescribed Mifepristone in Canada.

BACKGROUND: In the United States, mifepristone is available for medical abortion (for use with misoprostol) only with Risk Evaluation and Mitigation Strategy (REMS) restrictions, despite an absence of evidence to support such restrictions. Mifepristone has been available in Canada with a normal prescription since November 2017. METHODS: Using population-based administrative data from Ontario, Canada, we examined abortion use, safety, and effectiveness using an interrupted time-series analysis comparing trends in incidence before mifepristone was available (January 2012 through December 2016) with trends after its availability without restrictions (November 7, 2017, through March 15, 2020). RESULTS: A total of 195,183 abortions were performed before mifepristone was available and 84,032 after its availability without restrictions. After the availability of mifepristone with a normal prescription, the abortion rate continued to decline, although more slowly than was expected on the basis of trends before mifepristone had been available (adjusted risk difference in time-series analysis, 1.2 per 1000 female residents between 15 and 49 years of age; 95% confidence interval [CI], 1.1 to 1.4), whereas the percentage of abortions provided as medical procedures increased from 2.2% to 31.4% (adjusted risk difference, 28.8 percentage points; 95% CI, 28.0 to 29.7). There were no material changes between the period before mifepristone was available and the nonrestricted period in the incidence of severe adverse events (0.03% vs. 0.04%; adjusted risk difference, 0.01 percentage points; 95% CI, -0.06 to 0.03), complications (0.74% vs. 0.69%; adjusted risk difference, 0.06 percentage points; 95% CI, -0.07 to 0.18), or ectopic pregnancy detected after abortion (0.15% vs. 0.22%; adjusted risk difference, -0.03 percentage points; 95% CI, -0.19 to 0.09). There was a small increase in ongoing intrauterine pregnancy continuing to delivery (adjusted risk difference, 0.08 percentage points; 95% CI, 0.04 to 0.10). CONCLUSIONS: After mifepristone became available as a normal prescription, the abortion rate remained relatively stable, the proportion of abortions provided by medication increased rapidly, and adverse events and complications remained stable, as compared with the period when mifepristone was unavailable. (Funded by the Canadian Institutes of Health Research and the Women's Health Research Institute.).

Dispensing and practice use patterns, facilitators and barriers for uptake of ulipristal acetate emergency contraception in British Columbia: a mixed-methods study.

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.

Birth Outcomes for Planned Home and Licensed Freestanding Birth Center Births in Washington State.

OBJECTIVE: To describe rates of maternal and perinatal birth outcomes for community births and to compare outcomes by planned place of birth (home vs state-licensed, freestanding birth center) in a Washington State birth cohort, where midwifery practice and integration mirrors international settings. METHODS: We conducted a retrospective cohort study including all births attended by members of a statewide midwifery professional association that were within professional association guidelines and met eligibility criteria for planned birth center birth (term gestation, singleton, vertex fetus with no known fluid abnormalities at term, no prior cesarean birth, no hypertensive disorders, no prepregnancy diabetes), from January 1, 2015 through June 30, 2020. Outcome rates were calculated for all planned community births in the cohort. Estimated relative risks were calculated comparing delivery and perinatal outcomes for planned births at home to state-licensed birth centers, adjusted for parity and other confounders. RESULTS: The study population included 10,609 births: 40.9% planned home and 59.1% planned birth center births. Intrapartum transfers to hospital were more frequent among nulliparous individuals (30.5%; 95% CI 29.2-31.9) than multiparous individuals (4.2%; 95% CI 3.6-4.6). The cesarean delivery rate was 11.4% (95% CI 10.2-12.3) in nulliparous individuals and 0.87% (95% CI 0.7-1.1) in multiparous individuals. The perinatal mortality rate after the onset of labor (intrapartum and neonatal deaths through 7 days) was 0.57 (95% CI 0.19-1.04) per 1,000 births. Rates for other adverse outcomes were also low. Compared with planned birth center births, planned home births had similar risks in crude and adjusted analyses. CONCLUSION: Rates of adverse outcomes for this cohort in a U.S. state with well-established and integrated community midwifery were low overall. Birth outcomes were similar for births planned at home or at a state-licensed, freestanding birth center.

Short interpregnancy interval and pregnancy outcomes: How important is the timing of confounding variable ascertainment?

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.

Variation in relationships between maternal age at first birth and pregnancy outcomes by maternal race: a population-based cohort study in the United States.

OBJECTIVE: To estimate absolute risks of obstetric outcomes in the USA according to maternal age at first birth from age 15 to 45 separately by maternal race. DESIGN AND SETTING: Population-based cohort study. SETTING: Vital statistics Birth Cohort-Linked Birth- Infant Death Data Files and Fetal Death Data Files in the USA. PARTICIPANTS: 16 514 849 births to nulliparous women from 2004 to 2013. OUTCOME MEASURES: We estimated absolute risks of obstetric outcomes (multiple gestations, caesarean delivery, early and late preterm birth, small for gestational age birth, stillbirth, neonatal mortality, postneonatal infant mortality) at each year of maternal age from 15 to 45 years using logistic regression in the overall population and stratified by maternal race. We modelled maternal age flexibly to allow curvilinear shapes and plotted risk curves for each outcome. RESULTS: In the overall population, multiple gestations, caesarean delivery and stillbirth risks were lowest at young maternal ages with linear or quadratic increases with age. Curves for preterm birth, small for gestational age, neonatal mortality and postneonatal mortality were u or j shaped, with nadirs between 20 and 29 years, and elevated risks at both younger and older maternal ages. In race-stratified analyses, the shapes of the curves were generally similar across races. Risks increased for all women for all outcomes after age 30. However, increased risks at young maternal ages were most pronounced for white and Asian/Pacific Islander women, for whom young childbearing was least common. Conversely, risks at older ages were more pronounced for Black and American Indian/Alaska Native women, for whom delayed childbearing was least common. CONCLUSION: Our findings confirm risks associated with first births to women younger than 20 and older than 30 years, provide easily interpretable risk curves and illuminate variability in these relationships across categories of maternal race in the USA.

Household income and contraceptive methods among female youth: a cross-sectional study using the Canadian Community Health Survey (2009-2010 and 2013-2014).

BACKGROUND: Low socioeconomic status is one of many barriers that may limit access to family planning services. We aimed to examine the relation between household income and contraceptive methods among female youth in Canada. METHODS: Our study population included sexually active females aged 15-24 who were trying to avoid pregnancy. We used cross-sectional data from the 2009-2010 and 2013-2014 cycles of the Canadian Community Health Survey to compare household income and other sociodemographic covariates for those using oral contraceptives, injectable contraceptives, condoms or a dual method (condoms plus oral or injectable contraceptives). RESULTS: Of female youth at risk for unintended pregnancy, 59.2% reported using oral contraceptives, 29.0% used dual methods, 16.8% used condoms only, 2.5% used injectable contraceptives and 13.6% did not use contraception. In multiple regression models, lower annual household income (< $80 000) was associated with decreased use of oral contraceptives (relative risk [RR] 0.85, 95% confidence interval [CI] 0.80-0.91) and dual methods (RR 0.81, 95% CI 0.71-0.91), increased use of condoms (RR 1.36, 95% CI 1.11-1.67) and injectable contraceptives (RR 1.69, 95% CI 0.98-2.92), and a greater risk of contraceptive nonuse (RR 1.19, 95% CI 0.94-1.50). INTERPRETATION: We found that lower household income was associated with decreased use of oral contraceptives and increased reliance on injectable contraceptives and condoms only. Young, low-income females may face barriers to accessing the full range of contraceptive methods available in Canada. Easier access to affordable contraception may decrease the number of female youth at risk for unintended pregnancy due to financial barriers.

The Giving Voice to Mothers study: inequity and mistreatment during pregnancy and childbirth in the United States.

BACKGROUND: Recently WHO researchers described seven dimensions of mistreatment in maternity care that have adverse impacts on quality and safety. Applying the WHO framework for quality care, service users partnered with NGOs, clinicians, and researchers, to design and conduct the Giving Voice to Mothers (GVtM)-US study. METHODS: Our multi-stakeholder team distributed an online cross-sectional survey to capture lived experiences of maternity care in diverse populations. Patient-designed items included indicators of verbal and physical abuse, autonomy, discrimination, failure to meet professional standards of care, poor rapport with providers, and poor conditions in the health system. We quantified the prevalence of mistreatment by race, socio-demographics, mode of birth, place of birth, and context of care, and describe the intersectional relationships between these variables. RESULTS: Of eligible participants (n = 2700), 2138 completed all sections of the survey. One in six women (17.3%) reported experiencing one or more types of mistreatment such as: loss of autonomy; being shouted at, scolded, or threatened; and being ignored, refused, or receiving no response to requests for help. Context of care (e.g. mode of birth; transfer; difference of opinion) correlated with increased reports of mistreatment. Experiences of mistreatment differed significantly by place of birth: 5.1% of women who gave birth at home versus 28.1% of women who gave birth at the hospital. Factors associated with a lower likelihood of mistreatment included having a vaginal birth, a community birth, a midwife, and being white, multiparous, and older than 30 years. Rates of mistreatment for women of colour were consistently higher even when examining interactions between race and other maternal characteristics. For example, 27.2% of women of colour with low SES reported any mistreatment versus 18.7% of white women with low SES. Regardless of maternal race, having a partner who was Black also increased reported mistreatment. CONCLUSION: This is the first study to use indicators developed by service users to describe mistreatment in childbirth in the US. Our findings suggest that mistreatment is experienced more frequently by women of colour, when birth occurs in hospitals, and among those with social, economic or health challenges. Mistreatment is exacerbated by unexpected obstetric interventions, and by patient-provider disagreements.

Association of Short Interpregnancy Interval With Pregnancy Outcomes According to Maternal Age.

Importance: Interpregnancy intervals shorter than 18 months are associated with higher risks of adverse pregnancy outcomes. It is currently unknown whether short intervals are associated with increased risks among older women to the same extent as among younger women. Objective: To evaluate whether the association between short interpregnancy (delivery to conception) interval and adverse pregnancy outcomes is modified by maternal age. Design, Setting, and Participants: A population-based cohort study conducted in British Columbia, Canada, evaluated women with 2 or more singleton pregnancies from 2004 to 2014 with the first (index) pregnancy resulting in a live birth. Data analysis was performed from January 1 to July 20, 2018. Main Outcomes and Measures: Risks of maternal mortality or severe morbidity (eg, mechanical ventilation, blood transfusion >3 U, intensive care unit admission, organ failure, death), small-for-gestational age (<10th birthweight percentile for gestational age and sex), fetal and infant composite outcome (stillbirth, infant death,

Absolute risks of obstetric outcomes by maternal age at first birth: a population-based cohort.

BACKGROUND: First deliveries in women older than 35, 40, or 45 years are at increased risk for adverse pregnancy outcomes compared with those in younger women. However, specific relationships between each additional year of maternal age and pregnancy risks remain unclear, and absolute risks at each maternal age are not known. METHODS: Using a population-based cohort of nulliparous women in British Columbia, Canada, from 2004 to 2014 (n = 203,414), We examined relationships between maternal age (modeled flexibly to allow curvilinear shapes) and pregnancy outcomes using logistic regression. We plotted absolute predicted risks to display curves from age 20 to 50 estimated for two risk profiles: (1) population average values of all risk factors; (2) a low-risk profile without preexisting diabetes/hypertension, smoking, prior spontaneous/therapeutic abortion, diagnosed infertility, inadequate prenatal care, low income, rural residence, or obesity. RESULTS: Risks of hypertensive disorders increased gradually until age 35, then accelerated. Risk of multiple gestations, major congenital anomalies, and maternal mortality or severe morbidity increased slowly until age 30, then accelerated. Cesarean delivery and gestational diabetes risks increased linearly with age. While indicated preterm delivery increased rapidly with maternal age, spontaneous preterm delivery did not. Stillbirth, neonatal mortality, and infant mortality had j-shaped relationships with maternal age, with nadirs near 30. Despite age-related increases, risks of severe outcomes remained low for women 35 and 40: < 1-2% for severe maternal morbidity and 5-7% for fetal-infant composite. CONCLUSIONS: This study provides risks for specific maternal ages to inform clinical counseling and public health messaging regarding the potential implications of delayed childbearing.

Inter-pregnancy interval and pregnancy outcomes among women with delayed childbearing: protocol for a systematic review.

BACKGROUND: Women in high resource nations are increasingly delaying childbearing until their thirties. Delayed childbearing poses challenges for the spacing of a woman's pregnancies. Inter-pregnancy intervals <12 months are associated with risk for adverse pregnancy outcome, yet increased maternal age at delivery is linked with increased risk. The optimal inter-pregnancy interval for older mothers is uncertain. This systematic review will aim to assess the relation between inter-pregnancy interval and perinatal and maternal health outcomes in women who delay childbearing to age 30 and older. METHODS: We will search MEDLINE, CINAHL, and EMBASE databases for peer-reviewed articles on the effects of inter-pregnancy interval on perinatal and maternal health outcomes among women over 29 years at the time of first birth, in high-income countries. To assess the quality of studies, the Cochrane's Collaboration tool for assessing risk of bias will be used for randomized controlled trials, and the Newcastle-Ottawa tool to assess quality of case control and cross-sectional studies. The quality of the findings on each outcome will be assessed across studies, using the GRADE approach. The decision to conduct meta-analyses will be based on the concordance in definitions used for inter-pregnancy intervals, age groups studied, or outcomes measured among selected studies. We will report odds ratios and/or relative risks and/or risk differences for different inter-pregnancy intervals and perinatal and maternal outcomes as well as pregnancy complications. DISCUSSION: This systematic review will summarize existing data on the relation between inter-pregnancy interval and perinatal and maternal health outcomes among women who delay childbearing to age 30 and older. Findings will inform clinical best practices to assist mothers over age 30 to space their pregnancies appropriately. SYSTEMATIC REVIEW REGISTRATION: Prospero CRD42015019057.

Predictor characteristics necessary for building a clinically useful risk prediction model: a simulation study.

BACKGROUND: Compelled by the intuitive appeal of predicting each individual patient's risk of an outcome, there is a growing interest in risk prediction models. While the statistical methods used to build prediction models are increasingly well understood, the literature offers little insight to researchers seeking to gauge a priori whether a prediction model is likely to perform well for their particular research question. The objective of this study was to inform the development of new risk prediction models by evaluating model performance under a wide range of predictor characteristics. METHODS: Data from all births to overweight or obese women in British Columbia, Canada from 2004 to 2012 (n = 75,225) were used to build a risk prediction model for preeclampsia. The data were then augmented with simulated predictors of the outcome with pre-set prevalence values and univariable odds ratios. We built 120 risk prediction models that included known demographic and clinical predictors, and one, three, or five of the simulated variables. Finally, we evaluated standard model performance criteria (discrimination, risk stratification capacity, calibration, and Nagelkerke's r2) for each model. RESULTS: Findings from our models built with simulated predictors demonstrated the predictor characteristics required for a risk prediction model to adequately discriminate cases from non-cases and to adequately classify patients into clinically distinct risk groups. Several predictor characteristics can yield well performing risk prediction models; however, these characteristics are not typical of predictor-outcome relationships in many population-based or clinical data sets. Novel predictors must be both strongly associated with the outcome and prevalent in the population to be useful for clinical prediction modeling (e.g., one predictor with prevalence ≥20 % and odds ratio ≥8, or 3 predictors with prevalence ≥10 % and odds ratios ≥4). Area under the receiver operating characteristic curve values of >0.8 were necessary to achieve reasonable risk stratification capacity. CONCLUSIONS: Our findings provide a guide for researchers to estimate the expected performance of a prediction model before a model has been built based on the characteristics of available predictors.

Risk of adverse pregnancy outcomes by prepregnancy body mass index: a population-based study to inform prepregnancy weight loss counseling.

OBJECTIVE: To estimate the absolute risks of adverse maternal and perinatal outcomes based on small differences in prepregnancy body mass (eg, 10% of body mass or 10-20 pounds). METHODS: This population-based cohort study (N=226,958) was drawn from all singleton pregnancies in British Columbia (Canada) from 2004 to 2012. The relationships between prepregnancy body mass index (BMI) (as a continuous, nonlinear variable) and adverse pregnancy outcomes were examined using logistic regression models. Analyses were adjusted for maternal age, height, parity, and smoking in pregnancy. Adjusted absolute risks of each outcome are reported according to incremental differences in prepregnancy BMI and weight in pounds. RESULTS: A 10% difference in prepregnancy BMI was associated with at least a 10% lower risk of preeclampsia, gestational diabetes, indicated preterm delivery, macrosomia, and stillbirth. In contrast, larger differences in prepregnancy BMI (20-30% differences in BMI) were necessary to meaningfully reduce risks of cesarean delivery, shoulder dystocia, neonatal intensive care unit stay 48 hours or longer, and in-hospital newborn mortality. Prepregnancy BMI was not associated with risk of postpartum hemorrhage requiring intervention, severe maternal morbidity or maternal mortality, or spontaneous preterm delivery before 32 weeks of gestation. CONCLUSION: These results can inform prepregnancy weight loss counseling by defining achievable weight loss goals for patients that may reduce their risk of poor perinatal outcomes. LEVEL OF EVIDENCE: II.

The Canadian birth place study: examining maternity care provider attitudes and interprofessional conflict around planned home birth.

BACKGROUND: Available birth settings have diversified in Canada since the integration of regulated midwifery. Midwives are required to offer eligible women choice of birth place; and 25-30% of midwifery clients plan home births. Canadian provincial health ministries have instituted reimbursement schema and regulatory guidelines to ensure access to midwives in all settings. Evidence from well-designed Canadian cohort studies demonstrate the safety and efficacy of midwife-attended home birth. However, national rates of planned home birth remain low, and many maternity providers do not support choice of birth place. METHODS: In this national, mixed-methods study, our team administered a cross-sectional survey, and developed a 17 item Provider Attitudes to Planned Home Birth Scale (PAPHB-m) to assess attitudes towards home birth among maternity providers. We entered care provider type into a linear regression model, with the PAPHB-m score as the outcome variable. Using Students' t tests and ANOVA for categorical variables and correlational analysis (Pearson's r) for continuous variables, we conducted provider-specific bivariate analyses of all socio-demographic, education, and practice variables (n=90) that were in both the midwife and physician surveys. RESULTS: Median favourability scores on the PAPHB-m scale were very low among obstetricians (33.0), moderately low for family physicians (38.0) and very high for midwives (80.0), and 84% of the variance in attitudes could be accounted for by care provider type. Amount of exposure to planned home birth during midwifery or medical education and practice was significantly associated with favourability scores. Concerns about perinatal loss and lawsuits, discomfort with inter-professional consultations, and preference for the familiarity of the hospital correlated with less favourable attitudes to home birth. Among all providers, favourability scores were linked to beliefs about the evidence on safety of home birth, and confidence in their own ability to manage obstetric emergencies at a home birth. CONCLUSIONS: Increasing the knowledge base among all maternity providers about planned home birth may increase favourability. Key learning competencies include criteria for birth site selection, management of obstetric emergencies at planned home births, critical appraisal of literature on safety of home birth, and inter-professional communication and collaboration when women are transferred from home to hospital.