Maureen Heaman

Severe maternal morbidity in Canada, 1991-2001.

Background: Although death rates are often used to monitor the quality of health care, in industrialized countries maternal deaths have become rare. Severe maternal morbidity has therefore been proposed as a supplementary indicator for surveillance of the quality of maternity care. Our purpose in this study was to describe severe maternal morbidity in Canada over a 10-year period, among women with or without major pre-existing conditions. Methods: We carried out a retrospective cohort study of severe maternal morbidity involving 2 548 824 women who gave birth in Canadian hospitals between 1991 and 2000. Thirteen conditions that may threaten the life of the mother (e.g., eclampsia) and 11 major pre-existing chronic conditions (e.g., diabetes) that could be identified from diagnostic codes were noted. Results: The overall rate of severe maternal morbidity was 4.38 per 1000 deliveries. The fatality rate among these women was 158 times that of the entire sample. Rates of venous thromboembolism, uterine rupture, adult respiratory distress syndrome, pulmonary edema, myocardial infarction, severe postpartum hemorrhage requiring hysterectomy, and assisted ventilation increased substantially from 1991 to 2000. The presence of major pre-existing conditions increased the risk of severe maternal morbidity to 6-fold. Interpretation: Severe maternal morbidity occurs in about 1 of 250 deliveries in Canada, with marked recent increases in certain morbid conditions such as pulmonary edema, myocardial infarction, hemorrhage requiring hysterectomy, and the use of assisted ventilation.

Risk of maternal postpartum readmission associated with mode of delivery.

OBJECTIVE: To determine whether cesarean and operative vaginal deliveries are associated with an increased risk of maternal rehospitalization compared with spontaneous vaginal delivery. METHODS: A population-based cohort study was conducted by using the Canadian Institute for Health Informations Discharge Abstract Database between 1997/1998 and 2000/2001, which included 900,108 women aged 15–44 years with singleton live births (after excluding several selected obstetric conditions). RESULTS: A total of 16,404 women (1.8%) were rehospitalized within 60 days after initial discharge. Compared with spontaneous vaginal delivery (rate 1.5%), cesarean delivery was associated with a significantly increased risk of postpartum readmission (rate 2.7%, odds ratio [OR] 1.9, 95% confidence interval [CI] 1.8–1.9); ie, there was 1 excess postpartum readmission per 75 cesarean deliveries. Diagnoses associated with significantly increased risks of readmission after cesarean delivery (compared with spontaneous vaginal delivery) included pelvic injury/wounds (rate 0.86% versus 0.06%, OR 13.4, 95% CI 12.0–15.0), obstetric complications (rate 0.23% versus 0.08%, OR 3.0, 95% CI 2.6–3.5), venous disorders and thromboembolism (rate 0.07% versus 0.03%, OR 2.7, 95% CI 2.1–3.4), and major puerperal infection (rate 0.45% versus 0.27%, OR 1.8, 95% CI 1.6–1.9). Women delivered by forceps or vacuum were also at an increased risk of readmission (rates 2.2% and 1.8% versus 1.5%; OR forceps: 1.4, 95% CI 1.3–1.5; OR vacuum: 1.2, 95% CI 1.2–1.3, respectively). Higher readmission rates after operative vaginal delivery were due to pelvic injury/wounds, genitourinary conditions, obstetric complications, postpartum hemorrhage, and major puerperal infection. CONCLUSION: Compared with spontaneous vaginal delivery, cesarean delivery, and operative vaginal delivery increase the risk of maternal postpartum readmission. LEVEL OF EVIDENCE: II-2

Breastfeeding Rates and Hospital Breastfeeding Practices in Canada: A National Survey of Women

BACKGROUND The Baby-Friendly Hospital Initiative was launched by the World Health Organization and UNICEF in 1989 to promote, protect, and support breastfeeding worldwide. The objective of this study was to report breastfeeding rates and adherence to the Baby Friendly Hospital Initiative of the World Health Organization and UNICEF in Canada, as reported by participants in the Maternity Experiences Survey of the Canadian Perinatal Surveillance System. METHODS Eligible women (n = 8,244) were identified from a randomly selected sample of infants born 3 months before the May 2006 Canadian Census, and stratified by province or 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 took approximately 45 minutes and were completed when infants were between 5 and 10 months old (between 9 and 14 months in the territories). Completed responses were obtained from 6,421 women (78% response rate). Nineteen of 309 questions concerned early mother-infant contact and breastfeeding practices. RESULTS Breastfeeding intention (90.0%) and initiation (90.3%) rates were high, although exclusive breastfeeding rates at 6 months after birth (14.4%) were lower than desirable. The findings suggested a low adherence to several best practices advocated by the Baby-Friendly Hospital Initiative. CONCLUSION Although breastfeeding initiation rates were relatively high in Canada, exclusive breastfeeding duration fell short of globally recommended standards.

Advanced Maternal Age and the Risk of Cesarean Birth: A Systematic Review

BACKGROUND The increasing pregnancy rate at advanced maternal age is contemporaneous with the increasing rate of cesarean birth. Several studies have found that advanced maternal age is a risk factor for cesarean birth. The objective of this systematic review was to assess the relationship between advanced maternal age and cesarean birth among nulliparous and multiparous women. METHODS To identify relevant studies, we searched the literature for articles published from January 1, 1995 to March 1, 2008, using Medline, EMBASE, PsychINFO, and CINAHL. We also hand-searched the bibliographies of retrieved articles to identify additional related studies. We included all cohort studies and all case-control studies that examined this association in developed countries. The Cochrane Collaborations Review Manager software (5.0) was used to summarize the data. RESULTS Twenty-one studies met the inclusion criteria and were included in the review. All studies demonstrated an increased risk of cesarean birth among women at advanced maternal age compared with younger women, for both nulliparas and multiparas (relative risk varied from 1.39 to 2.76). Because we found extreme heterogeneity (both statistical and clinical) among the included studies, we did not provide a pooled estimate of the risk of cesarean birth. CONCLUSIONS All included studies illustrated an increased risk of cesarean birth among older women. Fifteen studies adjusted this association for potential confounders, which suggests that a valid and independent association is likely to exist between advanced maternal age and cesarean birth. However, the associated factors for this increased risk are not totally understood in the literature.

International migration and adverse birth outcomes: role of ethnicity, region of origin and destination

Background The literature on international migration and birth outcomes shows mixed results. This study examined whether low birth weight (LBW) and preterm birth differed between non-migrants and migrant subgroups, defined by race/ethnicity and world region of origin and destination. Methods A systematic review and meta-regression analyses were conducted using three-level logistic models to account for the heterogeneity between studies and between subgroups within studies. Results Twenty-four studies, involving more than 30 million singleton births, met the inclusion criteria. Compared with US-born black women, black migrant women were at lower odds of delivering LBW and preterm birth babies. Hispanic migrants also exhibited lower odds for these outcomes, but Asian and white migrants did not. Sub-Saharan African and Latin-American and Caribbean women were at higher odds of delivering LBW babies in Europe but not in the USA and south-central Asians were at higher odds in both continents, compared with the native-born populations. Conclusions The association between migration and adverse birth outcomes varies by migrant subgroup and it is sensitive to the definition of the migrant and reference groups.

Inadequate prenatal care and its association with adverse pregnancy outcomes: A comparison of indices

BackgroundThe objectives of this study were to determine rates of prenatal care utilization in Winnipeg, Manitoba, Canada from 1991 to 2000; to compare two indices of prenatal care utilization in identifying the proportion of the population receiving inadequate prenatal care; to determine the association between inadequate prenatal care and adverse pregnancy outcomes (preterm birth, low birth weight [LBW], and small-for-gestational age [SGA]), using each of the indices; and, to assess whether or not, and to what extent, gestational age modifies this association.MethodsWe conducted a population-based study of women having a hospital-based singleton live birth from 1991 to 2000 (N = 80,989). Data sources consisted of a linked mother-baby database and a physician claims file maintained by Manitoba Health. Rates of inadequate prenatal care were calculated using two indices, the R-GINDEX and the APNCU. Logistic regression analysis was used to determine the association between inadequate prenatal care and adverse pregnancy outcomes. Stratified analysis was then used to determine whether the association between inadequate prenatal care and LBW or SGA differed by gestational age.ResultsRates of inadequate/no prenatal care ranged from 8.3% using APNCU to 8.9% using R-GINDEX. The association between inadequate prenatal care and preterm birth and LBW varied depending on the index used, with adjusted odds ratios (AOR) ranging from 1.0 to 1.3. In contrast, both indices revealed the same strength of association of inadequate prenatal care with SGA (AOR 1.4). Both indices demonstrated heterogeneity (non-uniformity) across gestational age strata, indicating the presence of effect modification by gestational age.ConclusionSelection of a prenatal care utilization index requires careful consideration of its methodological underpinnings and limitations. The two indices compared in this study revealed different patterns of utilization of prenatal care, and should not be used interchangeably. Use of these indices to study the association between utilization of prenatal care and pregnancy outcomes affected by the duration of pregnancy should be approached cautiously.

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.

Relationships between physical abuse during pregnancy and risk factors for preterm birth among women in Manitoba

OBJECTIVE To describe the prevalence and correlates of physical abuse during the year of pregnancy and to explore the association between physical abuse and other risk factors for preterm birth. DESIGN Secondary analysis of data from a case-control study of risk factors for preterm birth. SETTING Two tertiary care hospitals in the Canadian province of Manitoba. PARTICIPANTS Six hundred eighty postpartum women who delivered a live singleton newborn after spontaneous onset of labor. MAIN OUTCOME MEASURES Instruments included the Abuse Assessment Screen, Prenatal Psychosocial Profile, Perceived Stress Scale, and a questionnaire to collect data on demographic characteristics, complications during pregnancy, and lifestyle behaviors. RESULTS Sixty-four women (9.4%) reported being physically abused during the year of pregnancy. Abused women were significantly more likely to be younger, single, of lower income, and less educated than nonabused women. Significant correlates of abuse, after adjusting for other factors in a logistic regression, included the following: illicit drug use, low support from partner, moving two or more times in the past year, high life event stress, bladder infection during pregnancy, Aboriginal race/ethnicity, and single marital status. CONCLUSION This study suggests that physical abuse during pregnancy is associated with other risk factors for preterm birth, particularly stress and behavioral risk factors such as substance abuse.

Comparison of Adolescent, Young Adult, and Adult Women’s Maternity Experiences and Practices

BACKGROUND AND OBJECTIVE: Pregnant adolescents face unique challenges. Understanding the experiences, knowledge, and behaviors of adolescents during the pregnancy and postpartum periods may contribute to improvement of their maternity care. The purpose of this study was to compare the maternity experiences, knowledge, and behaviors of adolescent, young adult, and adult women by using a nationally representative sample. METHODS: This study used data from the Canadian Maternity Experiences Survey (N = 6421). The weighted proportions of each variable were calculated by using survey sample weights. Logistic regression was used to estimate odds ratios. Bootstrapping techniques were used to calculate variance estimates for prevalence and 95% confidence intervals. RESULTS: Adolescents and young adults were more likely to experience physical abuse in the previous 2 years, initiate prenatal care late, not take folic acid before or during pregnancy, have poor prenatal health behaviors, have a lower cesarean delivery rate, have lower breastfeeding initiation and duration rates, experience more stressful life events, experience postpartum depression symptoms, and rate their infant’s health as suboptimal than adult women. Adolescents were more likely to rate their own health as suboptimal. CONCLUSIONS: Adolescents have unique needs during pregnancy and postpartum. Health care professionals should seek to provide care in a manner that acknowledges these needs.

Social inequalities in use of prenatal care in Manitoba.

OBJECTIVE Analysis of regional variations in use of prenatal care to identify individual-level and neighbourhood-level determinants of inadequate prenatal care among women giving birth in the province of Manitoba. METHODS Data were obtained from Manitoba Health administrative databases and the 1996 Canadian Census. An index of prenatal care use was calculated for each singleton live birth from 1991 to 2000 (N = 149,291). Births were geocoded into 498 geographic districts, and a spatial analysis was conducted, consisting of data visualization, spatial clustering, and data modelling using Poisson regression. RESULTS We found wide variation in rates of inadequate prenatal care across geographic areas, ranging from 1.1% to 21.5%. Higher rates of inadequate care were found in the inner-city of Winnipeg and in northern Manitoba. After adjusting for individual characteristics, the highest rates of inadequate prenatal care were among women living in neighbourhoods with the lowest average family income, the highest proportion of the population who were unemployed, the highest rates of recent immigrants, the highest percentage of the population reporting Aboriginal status, the highest percentage of single parent families, the highest percentage of the population with fewer than nine years of education, and the highest rates of women who smoked during pregnancy. CONCLUSION Social inequalities exist in the use of prenatal care among Manitoba women, despite there being a universally funded health care system. Regional disparities in rates of inadequate prenatal care emphasize the need for further research to determine specific risk factors for inadequate prenatal care in socioeconomically disadvantaged neighbourhoods, followed by provision of effective targeted services.