Susie Dzakpasu

The Canadian Maternity Experiences Survey: Design and Methods

OBJECTIVE The Maternity Experiences Survey (MES) is an initiative of the Canadian Perinatal Surveillance System. Its primary objective is to provide representative, pan-Canadian data on womens experiences during pregnancy, birth, and the early postpartum period. METHODS The development of the survey involved input from a multidisciplinary study group, an extensive consultation process and two pilot studies. TheMES population consisted of birth mothers 15 years of age and over who had a singleton live birth in Canada during a three-month period preceding the 2006 Canadian Census of Population and who lived with their infants at the time of data collection. Experiences of teenage, immigrant, First Nations, Inuit, and Métis mothers were of particular interest. The sample was drawn from the 2006 Canadian Census. A 45-minute interview was conducted at five to 14 months postpartum, primarily by telephone by female professional Statistics Canada interviewers. RESULTS A response rate of 78% was achieved, corresponding to 6421 women who were weighted to represent an estimated 76508 women. The cooperation rate was 92% and the refusal rate was 1.0%. Item non-response was low, and few data errors were identified. The final MES sample was judged to be representative of the corresponding Census population for all characteristics investigated. CONCLUSION The MES marks an important milestone in the availability of information on maternity experiences in Canada. For the first time, it is possible to provide high quality data at national, provincial, and territorial levels on a wide spectrum of maternity experiences as reported by women.

A parsimonious explanation for intersecting perinatal mortality curves: understanding the effect of plurality and of parity

BackgroundBirth weight- and gestational age-specific perinatal mortality curves intersect when compared across categories of maternal smoking, plurality, race and other factors. No simple explanation exists for this paradoxical observation.MethodsWe used data on all live births, stillbirths and infant deaths in Canada (1991–1997) to compare perinatal mortality rates among singleton and twin births, and among singleton births to nulliparous and parous women. Birth weight- and gestational age-specific perinatal mortality rates were first calculated by dividing the number of perinatal deaths at any given birth weight or gestational age by the number of total births at that birth weight or gestational age (conventional calculation). Gestational age-specific perinatal mortality rates were also calculated using the number of fetuses at risk of perinatal death at any given gestational age.ResultsConventional perinatal mortality rates among twin births were lower than those among singletons at lower birth weights and earlier gestation ages, while the reverse was true at higher birth weights and later gestational ages. When perinatal mortality rates were based on fetuses at risk, however, twin births had consistently higher mortality rates than singletons at all gestational ages. A similar pattern emerged in contrasts of gestational age-specific perinatal mortality among singleton births to nulliparous and parous women. Increases in gestational age-specific rates of growth-restriction with advancing gestational age presaged rising rates of gestational age-specific perinatal mortality in both contrasts.ConclusionsThe proper conceptualization of perinatal risk eliminates the mortality crossover paradox and provides new insights into perinatal health issues.

Use of Routine Interventions in Vaginal Labor and Birth: Findings from the Maternity Experiences Survey

BACKGROUND Intervention rates in maternity practices vary considerably across Canadian provinces and territories. The objective of this study was to describe the use of routine interventions and practices in labor and birth as reported by women in the Maternity Experiences Survey of the Canadian Perinatal Surveillance System. Rates of interventions and practices are considered in the light of current evidence and both Canadian and international recommendations. METHODS A sample of 8,244 estimated eligible women was identified from a randomly selected sample of recently born infants drawn from the May 2006 Canadian Census and stratified primarily by province and territory. Birth mothers living with their infants at the time of interview were invited to participate in a computer-assisted telephone interview conducted by Statistics Canada on behalf of the Public Health Agency of Canada. Interviews averaged 45 minutes long and were completed when infants were between 5 and 10 months old (9-14 mo in the territories). Completed responses were obtained from 6,421 women (78%). RESULTS Women frequently reported electronic fetal monitoring, a health care practitioner starting or speeding up their labor (or trying to do so), epidural anesthesia, episiotomy, and a supine position for birth. Some women also reported pubic or perineal shaves, enemas, and pushing on the top of their abdomen. CONCLUSIONS Several practices and interventions were commonly reported in labor and birth in Canada, although evidence and Canadian and international guidelines recommend against their routine use. Practices not recommended for use at all, such as shaving, were also reported.

Comparison of Maternity Experiences of Canadian-Born and Recent and Non-Recent Immigrant Women: Findings From the Canadian Maternity Experiences Survey

OBJECTIVE To compare the maternity experiences of immigrant women (recent, ≤ 5 years in Canada; non-recent > 5 years) with those of Canadian-born women. METHODS This study was based on data from the Canadian Maternity Experiences Survey of the Public Health Agency of Canada. A stratified random sample of 6421 women was drawn from a sampling frame based on the 2006 Canadian Census of Population. Weighted proportions were calculated using survey sample weights. Multivariable logistic regression was used to estimate odds ratios comparing recent immigrant women with Canadian-born women and non-recent immigrant women with Canadian-born women, adjusting for education, income, parity, and maternal age. RESULTS The sample comprised 7.5% recent immigrants, 16.3% non-recent immigrants, and 76.2% Canadian-born women. Immigrant women reported experiencing less physical abuse and stress, and they were less likely to smoke or consume alcohol during pregnancy, than Canadian women; however, they were more likely to report high levels of postpartum depression symptoms and were less likely to have access to social support, to take folic acid before and during pregnancy, to rate their own and their infants health as optimal, and to place their infants on their backs for sleeping. Recent and non-recent immigrant women also had different experiences, suggesting that duration of residence in Canada plays a role in immigrant womens maternity experiences. CONCLUSION These findings can assist clinicians and policy-makers to understand the disparities that exist between immigrant and non-immigrant women in order to address the needs of immigrant women more effectively.

Contribution of prepregnancy body mass index and gestational weight gain to caesarean birth in Canada

BackgroundOverweight and obese women are known to be at increased risk of caesarean birth. This study estimates the contribution of prepregnancy body mass index (BMI) and gestational weight gain (GWG) to caesarean births in Canada.MethodsWe analyzed data from women in the Canadian Maternity Experiences Survey who had a singleton term live birth in 2005-2006. Adjusted odds ratios for caesarean birth across BMI and GWG groups were derived, separately for nulliparous women and parous women with and without a prior caesarean. Population attributable fractions of caesarean births associated with above normal BMI and excess GWG were calculated.ResultsThe overall caesarean birth rate was 25.7%. Among nulliparous and parous women without a previous caesarean birth, rates in obese women were 45.1% and 9.7% respectively, and rates in women who gained above their recommended GWG were 33.5% and 8.0% respectively. Caesarean birth was more strongly associated with BMI than with GWG. However, due to the high prevalence of excess GWG (48.8%), the proportion of caesareans associated with above normal BMI and excess GWG was similar [10.1% (95% CI: 9.9-10.2) and 10.9% (95% CI: 10.7-11.1) respectively]. Overall, one in five (20.2%, 95% CI: 20.0-20.4) caesarean births was associated with above normal BMI or excess GWG.ConclusionsOverweight and obese BMI and above recommended GWG are significantly associated with caesarean birth in singleton term pregnancies in Canada. Strategies to reduce caesarean births must include measures to prevent overweight and obese BMI prior to conception and promote recommended weight gain throughout pregnancy.

The Matthew Effect: Infant Mortality in Canada and Internationally

Objective. To examine whether the magnitude of improvement in the health status of a population over time is dependent on the previous health status of that population. Design and Setting. A study of infant mortality rates in Canadas 12 provinces and territories between the periods 1961–1965 and 1991–1995, and of infant mortality rates in 133 countries between 1960 and 1995. Main Outcome Measures. Spearmans rank correlations, relative risks, and risk differences to measure the relationship between infant mortality in the 1960s and changes in infant mortality between the 1960s and 1990s. Results. In Canada, regional rankings based on infant mortality rates in 1961–1965 were strongly correlated (inversely) with rankings based on the percent change in infant mortality between 1961–1965 and 1991–1995 (correlation coefficient = −.85). In contrast, internationally, rankings based on infant mortality rates in 133 countries in 1960 were positively correlated with percent change between 1960 and 1995 (correlation coefficient = .56). Regional differences in infant mortality rates, measured using relative risks, declined in Canada (highest relative risk: 4.2, compared with Ontario in the 1960s; highest relative risk: 2.2, compared with Ontario in the 1990s) but increased globally (highest relative risk: 5.0, compared with industrialized countries in 1960; highest relative risk: 15.1, compared with industrialized countries in 1995). Conclusions. Canadian regions with higher infant mortality rates in 1961–1965 achieved larger improvements compared with regions with initially lower infant mortality rates. The pattern observed within Canada is unlike the pattern observed internationally.

Decreasing Diagnoses of Birth Asphyxia in Canada: Fact or Artifact

OBJECTIVE. We assessed temporal trends in birth asphyxia in Canada, to determine whether changes were real or secondary to changes in coding. METHODS. We used data from the Canadian Institute for Health Information Discharge Abstract Database to study the national incidence of birth asphyxia, by using International Classification of Diseases codes. We also studied birth asphyxia by using data from the Nova Scotia Atlee Perinatal Database. In the Nova Scotia Atlee Perinatal Database, we defined a case of birth asphyxia as a live birth with an Apgar score at 5 minutes of ≤3, depression at birth requiring resuscitation with a mask for ≥3 minutes and/or intubation, or neonatal postasphyctic seizures. RESULTS. Nationally, between 1991 and 2005, the incidence of birth asphyxia decreased significantly, from 43.8 to 2.4 cases per 1000 live births. The rate of decrease was highest between 1991 and 1998, corresponding to a period when strict Canadian and international criteria for the diagnosis of birth asphyxia were published. By comparison, neither national rates of related diagnoses nor Nova Scotia birth asphyxia rates, which ranged from 8.8 to 14.3 cases per 1000 live births, showed evidence of a decrease during the study period. CONCLUSIONS. Comparisons of national trends in birth asphyxia diagnoses and trends in conditions associated with birth asphyxia, both nationally and in Nova Scotia, suggest that the dramatic decrease in the diagnosis of birth asphyxia is an artifact of changes in the use of International Classification of Diseases coding associated with the publication of stricter diagnostic definitions of birth asphyxia. We conclude that International Classification of Diseases codes are not useful for surveillance of birth asphyxia.

Regional disparities in infant mortality in Canada: a reversal of egalitarian trends.

BackgroundAlthough national health insurance plans and social programs introduced in the 1960s led to reductions in regional disparities in infant mortality in Canada, it is unclear if such patterns prevailed in the 1990s when the health care and related systems were under fiscal duress. This study examined regional patterns of change in infant mortality in Canada in recent decades.MethodsWe analysed regional changes in crude infant mortality rates and in infant mortality rates among live births with a birth weight ≥ 500 g and ≥ 1,000 g in Canada from 1945 to 2002. Associations between baseline infant mortality rates in the provinces and territories (e.g., in 1985–89) and the change observed in infant mortality rates over the subsequent period (e.g., between 1985–89 and 1995–99) were assessed using Spearmans rank correlation coefficient. Trends in regional disparities were also assessed by calculating period-specific rate ratios between provinces/territories with the highest versus the lowest infant mortality.ResultsProvincial/territorial infant mortality rates in 1945–49 were not correlated with changes in infant mortality over the next 10 years (rho = 0.01, P = 0.99). However, there was a strong negative correlation between infant mortality rates in 1965–69 and the subsequent decline in infant mortality (rho = - 0.85, P = 0.002). Provinces/territories with higher infant mortality rates in 1965–69 (Northwest Territories 64.7 vs British Columbia 20.7 per 1,000 live births) experienced relatively larger reductions in infant mortality between 1965–69 and 1975–79 (53.7% decline in the Northwest Territories vs a 36.6% decline in British Columbia). This pattern was reversed in the more recent decades. Provinces/territories with higher infant mortality rates ≥ 500 g in 1985–89 experience relatively smaller reductions in infant mortality between 1985–89 and 2000–02 (rho = 0.82, P = 0.004). The infant mortality ≥ 500 g rate ratio (contrasting the province/territory with the highest versus lowest infant mortality) was 3.2 in 1965–69, 2.4 in 1975–79, 2.2 in 1985–89, 3.1 in 1995–99 and 4.1 in 2000–02.ConclusionFiscal constraints in the 1990s led to a reversal of provincial/territorial patterns of change in infant mortality in Canada and to an increase in regional health disparities.

Interventions in labour and birth and satisfaction with care: The Canadian Maternity Experiences Survey Findings

Objective: To examine whether interventions in labour and birth contributed to ratings of satisfaction with these experiences, in women giving birth vaginally or attempting a vaginal birth prior to giving birth by caesarean section. Background: Ratings of satisfaction with women’s overall experience of labour and birth have long been encouraged, yet remain challenging to assess or to interpret. Methods: Data from the Canadian Maternity Experiences Survey (MES) – a nationally representative sample of women who had a singleton live birth in 2005–2006 – were analysed. Associations between the number of and type of labour and birth interventions, and women’s satisfaction with the overall labour and birth experience and six aspects of caregiver interactions, were assessed. Results: Among women having vaginal births, fewer interventions during labour was significantly associated with higher overall satisfaction with the labour and birth experience (ranging from 75% of women having no interventions to 46.4% having eight or more interventions rating their experiences as ‘very postive’). The same pattern was observed for satisfaction with women’s perceptions of caregiver’s respect, concern for dignity, compassion shown to them, the information given to them, their involvement in decision making, and caregiver’s competence. Among women having unplanned caesarean sections following attempted vaginal birth, the number of interventions was not associated with satisfaction ratings; however, satisfaction ratings were consistently lower than among women giving birth vaginally. Conclusion: These findings provide support for demedicalising vaginal labour and birth as well as for optimising the potential for a vaginal birth rather than caesarean section.

Prevalence of gestational diabetes among Chinese and South Asians: A Canadian population-based analysis

BACKGROUND There is considerable geographic variation in gestational diabetes mellitus (GDM) rates. We used data from two Canadian provinces, British Columbia (BC) and Alberta (AB), to determine the impact of ethnicity on GDM prevalence and neonatal outcomes. RESEARCH DESIGN AND METHODS All deliveries between 04/01/2004 and 03/31/2010 in AB (n=249,796) and BC (n=248,217) were analyzed. We calculated GDM prevalence among Chinese, South-Asian, and the general population (predominantly Caucasian) women. RESULTS Overall GDM prevalence was 4.8% (n=12,036) in AB and 7.2% (n=17,912) in BC. In both provinces, the prevalence of GDM was significantly higher in Chinese (AB:11%; BC:13.5%) and South Asian women (AB:8.4%;BC:13.9%) compared to the general population (AB:4.2%; BC: 5.8%). Chinese women were significantly older (AB:32.7; BC:33.0years) compared to the general population (AB:29.1; BC:30.1years). The odds of GDM relative to the general-population were 2-fold higher for South Asians in both provinces and almost 3-fold higher for Chinese in BC. Among GDM cases, compared to the general population, Chinese and South Asian infants were less likely to be LGA, more likely to be SGA, and had similar neonatal mortality rates. CONCLUSIONS Compared to the general population, GDM prevalence is higher in Chinese and South Asian Canadians. Increased maternal age is a major contributor to higher prevalence of GDM in Chinese women. GDM rates were higher in both ethnic and general population women in BC compared to AB, suggesting that in addition to differences in ethnic distribution, differences in diagnostic practices are likely contributing to observed geographic differences in GDM prevalence.