Juan Andrés León

Incidence, risk factors, and associated complications of eclampsia.

OBJECTIVE: To estimate trends in incidence and identify risk factors and maternal and neonatal consequences of eclampsia in Canada. METHODS: We conducted a population-based cohort study of all women and their newborns (N=1,910,729) delivered in the hospital in Canada (excluding Quebec) from 2003 to 2009. The data were obtained from the Canadian Institute for Health Information. Logistic models were used to examine the association with potential determinants and consequences of eclampsia. RESULTS: The incidence of eclampsia declined dramatically from 12.4 per 10,000 deliveries in 2003 to 5.9 in 2009. Among singleton deliveries, nulliparity (adjusted odds ratio [OR] 2.3; 95% confidence interval [CI] 2.0–2.6), anemia (adjusted OR 2.4; 95% CI 2.0–3.0), and existing heart disease (adjusted OR 4.8; 95% CI 2.9–7.3) increased the risk of eclampsia. The declining trend in eclampsia remained unchanged after accounting for changes in potential determinants and risk factors during the study period. Eclampsia was associated with increased risks of maternal death (adjusted OR 26.8; 95% CI 9.7–73.8), assisted ventilation (adjusted OR 102.3; 95% CI 78.2–133.8), respiratory distress syndrome (adjusted OR 36.2; 95% CI 15.3–85.3), acute renal failure (adjusted OR 20.9; 95% CI 11.4–38.3), obstetric embolism (adjusted OR 9.1; 95% CI 4.1–19.9), and other complications. Adverse neonatal outcomes associated with eclampsia included neonatal death (adjusted OR 2.9; 95% CI 1.6–5.5), respiratory distress syndrome (adjusted OR 5.1; 95% CI 4.1–6.3), and small-for-gestational age birth (adjusted OR 2.6; 95% CI 2.3–3.0). CONCLUSION: Despite declining incidence and improved care of women with eclampsia, the condition remains strongly associated with serious adverse consequences. LEVEL OF EVIDENCE: II

Effect of Folic Acid Food Fortification in Canada on Congenital Heart Disease Subtypes

Background: Previous studies have yielded inconsistent results for the effects of periconceptional multivitamins containing folic acid and of folic acid food fortification on congenital heart defects (CHDs). Methods: We carried out a population-based cohort study (N=5 901 701) of all live births and stillbirths (including late-pregnancy terminations) delivered at ≥20 weeks’ gestation in Canada (except Québec and Manitoba) from 1990 to 2011. CHD cases were diagnosed at birth and in infancy (n=72 591). We compared prevalence rates and temporal trends in CHD subtypes before and after 1998 (the year that fortification was mandated). An ecological study based on 22 calendar years, 14 geographic areas, and Poisson regression analysis was used to quantify the effect of folic acid food fortification on nonchromosomal CHD subtypes (n=66 980) after controlling for changes in maternal age, prepregnancy diabetes mellitus, preterm preeclampsia, multiple birth, and termination of pregnancy. Results: The overall birth prevalence rate of CHDs was 12.3 per 1000 total births. Rates of most CHD subtypes decreased between 1990 and 2011 except for atrial septal defects, which increased significantly. Folic acid food fortification was associated with lower rates of conotruncal defects (adjusted rate ratio [aRR], 0.73, 95% confidence interval [CI], 0.62–0.85), coarctation of the aorta (aRR, 0.77; 95% CI, 0.61–0.96), ventricular septal defects (aRR, 0.85; 95% CI, 0.75–0.96), and atrial septal defects (aRR, 0.82; 95% CI, 0.69–0.95) but not severe nonconotruncal heart defects (aRR, 0.81; 95% CI, 0.65–1.03) and other heart or circulatory system abnormalities (aRR, 0.98; 95% CI, 0.89–1.11). ConclusionS: The association between food fortification with folic acid and a reduction in the birth prevalence of specific CHDs provides modest evidence for additional benefit from this intervention.

Temporal trends in sudden infant death syndrome in Canada from 1991 to 2005: contribution of changes in cause of death assignment practices and in maternal and infant characteristics

Gilbert NL, Fell DB, Joseph KS, Liu S, León JA, Sauve R, for the Fetal and Infant Health Study Group of the Canadian Perinatal Surveillance System. Temporal trends in sudden infant death syndrome in Canada from 1991 to 2005: contribution of changes in cause of death assignment practices and in maternal and infant characteristics. Paediatric and Perinatal Epidemiology 2012; 26: 124–130. The rate of sudden infant death syndrome (SIDS) declined significantly in Canada and the US between the late 1980s and the early 2000s. In the US, this decline was shown to be due in part to a shift in diagnosis, as deaths from accidental suffocation and strangulation in bed and from other ill-defined and unspecified cause increased concurrently. This study was undertaken to determine whether there was such a shift in diagnosis from SIDS to other causes of death in Canada, and to quantify the true temporal decrease in SIDS. Cause-specific infant death rates were compared across three periods: 1991–95, 1996–2000 and 2001–05 using the Canadian linked livebirth-infant death file. The temporal decline in SIDS was estimated after adjustment for maternal and infant characteristics such as maternal age and small-for-gestational age using logistic regression. Deaths from SIDS decreased from 78.4 [95% confidence interval (CI) 73.4, 83.4] per 100 000 livebirths in 1991–95, to 48.5 [95% CI 44.3, 52.7] in 1996–2000 and to 34.6 [95% CI 31.0, 38.3] in 2001–05. Mortality rates from other ill-defined and unspecified causes and accidental suffocation and strangulation in bed remained stable. The temporal decline in SIDS between 1991–95 and 2001–05 did not change substantially after adjustment for maternal and infant factors. It is unlikely that the temporal decline of SIDS in Canada was due to changes in cause-of-death assignment practices or in maternal and infant characteristics.

The relationship between awareness and supplementation: Which Canadian women know about folic acid and how does that translate into use?

OBJECTIVE: Although the benefit of folic acid (FA) to prevent neural tube defects (NTD) is well established, not all women take supplements in the periconceptional period. This study used data from the Public Health Agency of Canada’s Maternity Experiences Survey to evaluate determinants of awareness of FA among recently pregnant women in Canada, and the extent to which that translated into actual supplement usage.METHODS: Telephone interviews took place between October 23, 2006 and January 31, 2007 with women who were 5 to 14 months postpartum to survey their experiences during pregnancy, birth and the postpartum period. These analyses were conducted on women who responded to questions relating to FA supplementation. The 6,421 respondents were weighted to represent 76,508 women using weights which corresponded to the sampling strata, the mother’s first language and Aboriginal status.RESULTS: Overall, 77.6% of surveyed women knew that taking FA periconceptionally could help protect against NTD. Women who were younger, single or separated reported less awareness and use of FA, while higher maternal age, level of education and income were positively associated with both knowledge and use. Despite longstanding national guidelines for supplementation, there were regional variations in knowledge and use of FA.CONCLUSION: The data indicate clear socio-demographic differences among Canadian women with respect to their knowledge and use of FA. Although most women understood the benefits of FA supplementation, a little over a third of them did not take FA supplements prior to becoming pregnant, and less than half supplemented according to national guidelines. Identification of those subpopulations whose use of supplements is suboptimal may allow for targeted educational or other interventions to further encourage FA use.RésuméOBJECTIF: Les avantages de l’acide folique (AF) pour prévenir les anomalies du tube neural (ATN) sont bien démontrés, mais toutes les femmes ne prennent pas de suppléments nutritifs durant la période périconceptionnelle. Nous avons utilisé les données de l’Enquête sur les expériences de la maternité de l’Agence de la santé publique du Canada pour évaluer les déterminants de la connaissance de l’AF chez les femmes ayant été enceintes récemment au Canada, et la mesure dans laquelle cette connaissance se traduit par l’usage réel de suppléments.MÉTHODE: Nous avons mené des entrevues téléphoniques entre le 23 octobre 2006 et le 31 janvier 2007 avec des femmes entre le 5e et le 14e mois post-partum afin de connaître leur expérience durant la grossesse, l’accouchement et la période post-partum. Ces analyses ont été menées pour les femmes ayant répondu aux questions sur la supplémentation en AF. Les 6 421 répondantes ont été pondérées pour représenter 76 508 femmes à l’aide de pondérations correspondant aux strates de l’échantillon, à la langue maternelle de la mère et au statut autochtone.RÉSULTATS: Globalement, 77,6 % des femmes sondées savaient que la prise d’AF durant la période périconceptionnelle pouvait protéger contre les ATN. Les femmes plus jeunes, célibataires ou séparées ont déclaré moins connaître et moins utiliser l’AF, tandis que l’âge maternel, le niveau de scolarité et le revenu plus élevés étaient liés positivement à la connaissance et à l’utilisation de l’AF. Malgré les lignes directrices nationales de longue date sur la supplementation, il y avait des écarts régionaux dans la connaissance et l’utilisation de l’AF.CONCLUSION: Nos données indiquent des différences sociodémographiques claires entre les Canadiennes en ce qui a trait à leur connaissance et à leur utilisation de l’AF. Bien que la plupart des femmes connaissent les avantages de la supplémentation en AF, un peu plus du tiers n’avaient pas pris de suppléments d’AF avant de tomber enceintes, et moins de la moitié en avaient pris en respectant les lignes directrices nationales. L’identification des sous-populations chez qui l’utilisation des suppléments est sous-optimale pourrait permettre de mener des interventions ciblées (éducatives ou autres) pour mieux encourager l’utilisation de l’AF.

Human exposure to environmental contaminants and congenital anomalies: a critical review

Abstract Congenital anomalies are an important cause of infant mortality and disability. Developmental exposure to environmental contaminants is thought to increase the risk for congenital anomalies. Herein, we describe a critical review of the literature conducted between February and March 2014 yielding 3057 references from which 97 unique relevant articles published from 2003 through 2014 were evaluated. Common congenital anomalies including hypospadias, cryptorchidism, anogenital distance (AGD), congenital heart defects and oral clefts were well represented in the literature whereas other outcomes such as neural tube defects, limb deficiency defects and gastroschisis were rarely described. While definitions used for congenital anomalies and methods of ascertainment were usually consistent across studies, inconsistencies were frequently found in grouping of different congenital heart defects. Despite strong links between some congenital anomalies and parental occupation, these studies are unable to provide clear insight into the specific chemicals responsible owing to lack of direct measures of exposure. In comparison, data are mixed for contaminant exposures at concentrations representative of results from contemporary biomonitoring studies. Of the environmental contaminants studied, the association between phthalate exposures and developmental abnormalities of the male reproductive tract received the greatest attention. Important limitations of the literature studied relate to adequacy of sample size, absence of or weaknesses in exposure assessment methodologies, failure to account for biological plausibility and grouping of congenital anomalies with divergent mechanisms. We conclude that the literature is inadequate at this time to support a conclusion that exposure to environmental contaminants are or are not associated with increased risks for congenital anomalies in the general population.

Proportion of neonatal readmission attributed to length of stay for childbirth: a population-based cohort study

Objective Most literature on length of stay (LOS) for childbirth focuses on ‘early’ discharge as opposed to ‘optimal’ time of discharge and has conflicting results due to heterogeneous definitions of ‘early’ discharge and differing eligibility criteria for these programmes. We aimed to determine the LOS associated with the lowest neonatal readmission rate following childbirth by examining the incidence pattern of neonatal readmission for different LOS using the Kitagawa decomposition. Design Retrospective cohort study using administrative hospitalisation data. Setting Canada (excluding Quebec) from 2003 to 2010. Patients Term, singleton live births without congenital anomalies. Interventions LOS for childbirth. Main outcome measure Neonatal readmissions within 30 days of birth. Results 1 875 322 live births were included. Neonatal LOS peaked at day 1 (47.3%) after vaginal birth and day 3 (49.3%) following caesarean section; 4.2% of infants were readmitted following vaginal birth and 2.2% after caesarean section. In 2008–2010, most readmissions occurred among infants discharged in the first 2 days (83.8%) following a vaginal birth and among infants discharged in the first 3 days (81.7%) following a caesarean birth. Readmissions increased from 4.1% in 2003–2005 to 4.6% in 2008–2010 among vaginal births and from 2.0% to 2.4% among caesarean births and occurred mostly due to changes in the day-specific readmission rates and not due to reductions in LOS. Conclusions Patterns of readmission suggest that readmission rates are lowest following a 1–2-day stay following a vaginal birth and a 2–4-day stay following a caesarean birth given the outpatient support in the community.

Evaluation of the INTERGROWTH-21 st project newborn standard for use in Canada

Objective To evaluate the performance of the INTERGROWTH-21st Project newborn standard vis-a-vis the current Canadian birth weight-for-gestational age reference. Methods All hospital-based singleton live births in Canada (excluding Quebec) between 2002 and 2012 with a gestational age between 33 and 42 weeks were included using information obtained from the Canadian Institute for Health Information. Small- and large-for gestational age centile categories of the INTERGROWTH standard and Canadian reference were contrasted in terms of frequency distributions and rates of composite neonatal morbidity/mortality. Results Among 2,753,817 singleton live births, 0.87% and 9.63% were <3rd centile and >97th centile, respectively, of the INTERGROWTH standard, while 2.27% and 3.55% were <3rd centile and >97th centile, respectively, of the Canadian reference. Infants <3rd centile and >97th centile had a composite neonatal morbidity/mortality rate of 46.4 and 12.9 per 1,000 live births, respectively, under the INTERGROWTH standard and 30.9 and 16.6 per 1,000 live births, respectively, under the Canadian reference. The INTERGROWTH standard <3rd centile and >97th centile categories had detection rates of 3.14% and 9.74%, respectively, for composite neonatal morbidity/ mortality compared with 5.48% and 4.60%, respectively for the Canadian reference. Similar patterns were evident in high- and low-risk subpopulations. Conclusions The centile distribution of the INTERGROWTH newborn standard is left shifted compared with the Canadian reference, and this shift alters the frequencies and neonatal morbidity/mortality rates associated with specific centile categories. Further outcome-based research is required for defining abnormal growth categories before the INTERGROWTH newborn standard can be used.

High-risk pregnancy: Graphic representation of the maternal and fetal risks

Abstract An attempt to represent graphically and objectively the principal factors of maternal and fetal risks in a circular diagram is described; a space is reserved for the condition of the baby at birth and for the neonatal pathology. The diagram permits study of all the factors—socioeconomic, clinical, etc.—influencing fetal and neonatal welfare and particularly those responsible for perinatal loss, showing certain positive associations and interactions between those factors. It attempts to integrate various fields of knowledge as they relate directly or indirectly to the problem of perinatal loss. Furthermore, this procedure aids in the identification of the high-risk women and fetuses who should be carefully monitored and permits the prompt recognition of the symptomatology of acute or chronic fetal distress and decisive intervention when necessary. It contributes to the reduction of the perinatal morbidity and mortality rates, especially of permanent central nervous system damage. These are the goals of obstetricians, pediatricians, anesthesiologists, public health workers, and others.