Fabienne Simonet

Birth outcomes in the Inuit-inhabited areas of Canada

Background: Information on health disparities between Aboriginal and non-Aboriginal populations is essential for developing public health programs aimed at reducing such disparities. The lack of data on disparities in birth outcomes between Inuit and non-Inuit populations in Canada prompted us to compare birth outcomes in Inuit-inhabited areas with those in the rest of the country and in other rural and northern areas of Canada. Methods: We conducted a cohort study of all births in Canada during 1990–2000 using linked vital data. We identified 13 642 births to residents of Inuit-inhabited areas and 4 054 489 births to residents of all other areas. The primary outcome measures were preterm birth, stillbirth and infant death. Results: Compared with the rest of Canada, Inuit-inhabited areas had substantially higher rates of preterm birth (risk ratio [RR] 1.45, 95% confidence interval [CI] 1.38–1.52), stillbirth (RR 1.68, 95% CI 1.38–2.04) and infant death (RR 3.61, 95% CI 3.17–4.12). The risk ratios and absolute differences in risk for these outcomes changed little over time. Excess mortality was observed for all major causes of infant death, including congenital anomalies (RR 1.64), immaturity-related conditions (RR 2.96), asphyxia (RR 2.43), sudden infant death syndrome (RR 7.15), infection (RR 8.32) and external causes (RR 7.30). Maternal characteristics accounted for only a small part of the risk disparities. Substantial risk ratios for preterm birth, stillbirth and infant death remained when the comparisons were restricted to other rural or northern areas of Canada. Interpretation: The Inuit-inhabited areas had much higher rates of preterm birth, stillbirth and infant death compared with the rest of Canada and with other rural and northern areas. There is an urgent need for more effective interventions to improve maternal and infant health in Inuit-inhabited areas.

Optimal birth weight percentile cut‐offs in defining small‐ or large‐for‐gestational‐age

Aims:  It remains questionable what birth weight for gestational age percentile cut‐offs should be used in defining clinically important poor or excessive foetal growth. We aimed to evaluate the optimal birth weight percentile cut‐offs for defining small‐ or large‐for‐gestational‐age (SGA or LGA).

Diabetes in pregnancy may differentially affect neonatal outcomes for twins and singletons

Diabet. Med. 28, 1068–1073 (2011)

Effect on neonatal outcomes in gestational hypertension in twin compared with singleton pregnancies.

OBJECTIVE: We tested the hypothesis that gestational hypertension may have a more benign effect on neonatal outcomes in twin compared with singleton pregnancies, because the elevated blood pressure in twin pregnancies may partly or merely reflect the extra demand for blood supply. METHODS: A retrospective cohort study of 102,988 twin and 5,523,797 singleton live births using the U.S. birth cohort linked birth and infant death data sets, 1998–2000. Main outcomes are relative risks (RRs) of adverse neonatal outcomes: preterm birth, intrauterine growth restriction (less than the third percentile), low 5-minute Apgar score (less than 4), and neonatal death comparing gestational hypertensive with no-event healthy pregnancies for twins and singletons. RESULTS: For singletons, crude RRs (95% confidence intervals) comparing gestational hypertensive with healthy pregnancies were 2.23 (2.20–2.25) for preterm birth (17.4 compared with 7.8%), 2.49 (2.45–2.53) for intrauterine growth restriction (7.4 compared with 3.0%), 1.33 (1.21–1.45) for low 5-minute Apgar score (2.6 compared with 2.0 per 1,000), and 1.07 (0.96–1.19) for neonatal death (1.9 compared with 1.8 per 1,000), respectively. For twins, the corresponding RRs were much lower or showed reversed associations: 1.21 (1.19–1.24) (63.6 compared with 52.4%), 1.04 (0.98–1.11) (16.4 compared with 16.4%), 0.32 (0.23–0.46) (4.1 compared with 12.7 per 1,000), and 0.21 (0.14–0.30) (3.6 compared with 17.2 per 1,000), respectively. The adjusted odds ratios showed a similar risk pattern in twin compared with singleton pregnancies after controlling for maternal race, age, education, marital status, parity, smoking, alcohol use, perinatal care use, and mode of delivery. CONCLUSION: Gestational hypertension has a much more benign effect on neonatal outcomes in twin compared with singleton pregnancies. There might be a need for twin- or multiple fetus–specific recommendations for hypertension management in pregnancy, but further interventional studies are needed to test the hypothesis. LEVEL OF EVIDENCE: II-2

Primary birthing attendants and birth outcomes in remote Inuit communities - a natural "experiment" in Nunavik, Canada

Background: There is a lack of data on the safety of midwife-led maternity care in remote or indigenous communities. In a de facto natural “experiment”, birth outcomes were assessed by primary birthing attendant in two sets of remote Inuit communities. Methods: A geocoding-based retrospective birth cohort study in 14 Inuit communities of Nunavik, Canada, 1989–2000: primary birth attendants were Inuit midwives in the Hudson Bay (1529 Inuit births) vs western physicians in Ungava Bay communities (1197 Inuit births). The primary outcome was perinatal death. Secondary outcomes included stillbirth, neonatal death, post-neonatal death, preterm, small-for-gestational-age and low birthweight birth. Multilevel logistic regression was used to obtain the adjusted odds ratios (aOR) controlling for maternal age, marital status, parity, education, infant sex and plurality, community size and community-level random effects. Results: The aORs (95% confidence interval) for perinatal death comparing the Hudson Bay vs Ungava Bay communities were 1.29 (0.63 to 2.64) for all Inuit births and 1.13 (0.48 to 2.47) for Inuit births at ⩾28 weeks of gestation. There were no statistically significant differences in the crude or adjusted risks of any of the outcomes examined. Conclusion: Risks of perinatal death were somewhat but not significantly higher in the Hudson Bay communities with midwife-led maternity care compared with the Ungava Bay communities with physician-led maternity care. These findings are inconclusive, although the results excluding extremely preterm births are more reassuring concerning the safety of midwife-led maternity care in remote indigenous communities.

Association of macrosomia with perinatal and postneonatal mortality among First Nations people in Quebec

Background High prevalence of infant macrosomia (up to 36%, the highest in the world) has been reported in some First Nations communities in the Canadian province of Quebec and the eastern area of the province of Ontario. We aimed to assess whether infant macrosomia was associated with elevated risks of perinatal and postneonatal mortality among First Nations people in Quebec. Methods We calculated risk ratios (RRs) of perinatal and postneonatal mortality by birthweight for gestational age, comparing births to First Nations women (n = 5193) versus women whose mother tongue is French (n = 653 424, the majority reference group) in Quebec 1991–2000. Results The prevalence of infant macrosomia (birthweight for gestational age > 90th percentile) was 27.5% among births to First Nations women, which was 3.3 times (confidence interval [CI] 3.2–3.5) higher than the prevalence (8.3%) among births to women whose mother tongue is French. Risk ratios for perinatal mortality among births to First Nations women were 1.8 (95% CI 1.3–2.5) for births with weight appropriate for gestational age, 4.1 (95% CI 2.4–7.0) for small-for-gestational-age (< 10th percentile) births and < 1 (not significant) for macrosomic births compared to births among women whose mother tongue is French. The RRs for postneonatal mortality were 4.3 (95% CI 2.7–6.7) for infants with appropriate-for-gestational-age birthweight and 8.3 (95% CI 4.0–17.0) for infants with macrosomia. Interpretation Macrosomia was associated with a generally protective effect against perinatal death, but substantially greater risks of postneonatal death among births to First Nations women in Quebec versus women whose mother tongue is French.

Birth outcomes and infant mortality among First Nations Inuit, and non-Indigenous women by northern versus southern residence, Quebec

Background In circumpolar countries such as Canada, northern regions represent a unique geographical entity climatically, socioeconomically and environmentally. There is a lack of comparative data on birth outcomes among Indigenous and non-Indigenous subpopulations within northern regions and compared with southern regions. Methods A cohort study of all births by maternal mother tongue to residents of northern (2616 First Nations (North American Indians), 2388 Inuit and 5006 non-Indigenous) and southern (2563 First Nations, 810 643 non-Indigenous) Quebec, 1991–2000. Results Compared with births to southern non-Indigenous mother tongue women, births to northern women of all three mother tongue groups were at substantially elevated risks of infant death (adjusted OR (aOR) 1.7–2.9), especially postneonatal death (aOR 2.2–4.4) after controlling for maternal education, age, marital status and parity. The risk elevation in perinatal death was greater for southern First Nations (aOR 1.6) than for northern First Nations (aOR 1.2). Infant macrosomia was highly prevalent among First Nations in Quebec, especially in the north (31% vs 24% in the south). Within northern regions, Inuit births were at highest risk of preterm delivery (aOR 1.4) and infant death (aOR 1.6). Conclusion All northern infants (First Nations, Inuit or non-Indigenous) were at substantially elevated risk of infant death in Quebec, despite a universal health insurance system. Southern First Nations newborns have not benefited from the more advanced perinatal care facilities in southern regions. Environmental influences may partly account for the very high prevalence of macrosomia among First Nations in northern Quebec.

Individual- and Community-Level Disparities in Birth Outcomes and Infant Mortality among First Nations, Inuit and Other Populations in Quebec

Objective We assessed individual- and community-level disparities and trends in birth outcomes and infant mortality among First Nations (North American Indians) and Inuit versus other populations in Quebec, Canada. Methods A retrospective birth cohort study of all births to Quebec residents, 1991–2000. At the individual level, we examined outcomes comparing births to First Nations and Inuit versus other mother tongue women. At the community level, we compared outcomes among First Nations and Inuit communities versus other communities. Results First Nations and Inuit births were much less likely to be small-for-gestational-age but much more likely to be large-for-gestational-age compared to other births at the individual or community level, especially for First Nations. At both levels, Inuit births were 1.5 times as likely to be preterm. At the individual level, total fetal and infant mortality rates were 2 times as high for First Nations, and 3 times as high for Inuit. Infant mortality rates were 2 times as high for First Nations, and 4 times as high for Inuit. There were no reductions in these disparities between 1991–1995 and 1996–2000. Modestly smaller disparities in total fetal and infant mortality were observed for First Nations at the community level (risk ratio=1.6), but for Inuit there were similar disparities at both levels. These disparities remained substantial after adjusting for maternal characteristics. Conclusion There were large and persistent disparities in fetal and infant mortality among First Nations and Inuit versus other populations in Quebec based on individual- or community-level assessments, indicating a need to improve socioeconomic conditions as well as perinatal and infant care for Aboriginal peoples.

Temporal trends in Inuit, First Nations and non-Aboriginal birth outcomes in rural and northern Quebec

Objectives. The objective was to assess trends in Inuit, First Nations and non-Aboriginal birth outcomes in the rural and northern regions of Quebec. Study design and methods. In a birth cohort-based study of all births to residents of rural and northern Quebec from 1991 through 2000 (n = 177,193), we analyzed birth outcomes and infant mortality for births classified by maternal mother tongue (Inuit, First Nations or non-Aboriginal) and by community type (predominantly First Nations, Inuit or non-Aboriginal). Results. From 1991–1995 to 1996–2000, there was a trend of increasing rates of preterm birth for all 6 study groups. In all rural and northern areas, low birth weight rates increased significantly only for the Inuit mother tongue group [RR1.45 (95% CI 1.05–2.01)]. Stillbirth rates showed a non-significant increase for the Inuit mother tongue group [RR1.76 (0.64–4.83)]. Neonatal mortality rates decreased significantly in the predominantly non-Aboriginal communities and in the non-Aboriginal mother tongue group [RR0.78 (0.66–0.92)], and increased non-significantly for the First Nations mother tongue group [RR2.17 (0.71–6.62)]. Perinatal death rates increased for the First Nations mother tongue grouping in northern areas [RR2.19 (0.99–4.85)]. Conclusion. There was a disconcerting rise of some mortality outcomes for births to First Nations and Inuit mother tongue women and to women in predominantly First Nations and Inuit communities, in contrast to some improvements for births to non-Aboriginal mother tongue women and to women in predominantly non-Aboriginal communities in rural or northern Quebec, indicating a need for improving perinatal and neonatal health for Aboriginal populations in rural and northern regions.

Neighborhood Socioeconomic Characteristics, Birth Outcomes and Infant Mortality among First Nations and Non-First Nations in Manitoba, Canada

Objective Little is known about the possible impacts of neighborhood socioeconomic status on birth outcomes and infant mortality among Aboriginal populations. We assessed birth outcomes and infant mortality by neighborhood socioeconomic status among First Nations and non-First Nations in Manitoba. Study Design We conducted a retrospective birth cohort study of all live births (26,176 First Nations, 129,623 non-First Nations) to Manitoba residents, 1991–2000. Maternal residential postal codes were used to assign four measures of neighborhood socioeconomic status (concerning income, education, unemployment, and lone parenthood) obtained from 1996 census data. Results First Nations women were much more likely to live in neighborhoods of low socioeconomic status. First Nations infants were much more likely to die during their first year of life [risk ratio (RR) =1.9] especially during the postneonatal period (RR=3.6). For both First Nations and non-First Nations, living in neighborhoods of low socioeconomic status was associated with an increased risk of infant death, especially postneonatal death. For non-First Nations, higher rates of pre-term and small-for-gestational-age birth were consistently observed in low socioeconomic status neighborhoods, but for First Nations the associations were less consistent across the four measures of socioeconomic status. Adjusting for neighborhood socioeconomic status, the disparities in infant and postneonatal mortality between First Nations and non-First Nations were attenuated. Conclusion Low neighborhood socioeconomic status was associated with an elevated risk of infant death even among First Nations, and may partly account for their higher rates of infant mortality compared to non-First Nations in Manitoba.