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Biomedical subjects

K S Joseph

Publications and source records attributed to K S Joseph.

At least 37 records · Page 2Linked to original sources
PubMed2005

The perinatal effects of delayed childbearing.

OBJECTIVE: To determine if the rates of pregnancy complications, preterm birth, small for gestational age, perinatal mortality, and serious neonatal morbidity are higher among mothers aged 35-39 years or 40 years or older, compared with mothers 20-24 years. METHODS: We performed a population-based study of all women in Nova Scotia, Canada, who delivered a singleton fetus between 1988 and 2002 (N = 157,445). Family income of women who delivered between 1988 and 1995 was obtained through a confidential linkage with tax records (n = 76,300). The primary outcome was perinatal death (excluding congenital anomalies) or serious neonatal morbidity. Analysis was based on logistic models. RESULTS: Older women were more likely to be married, affluent, weigh 70 kg or more, attend prenatal classes, and have a bad obstetric history but less likely to be nulliparous and to smoke. They were more likely to have hypertension, diabetes mellitus, placental abruption, or placenta previa. Preterm birth and small-for-gestational age rates were also higher; compared with women aged 20-24 years, adjusted rate ratios for preterm birth among women aged 35-39 years and 40 years or older were 1.61 (95% confidence interval [CI] 1.42-1.82; P < .001) and 1.80 (95% CI 1.37-2.36; P < .001), respectively. Adjusted rate ratios for perinatal mortality/morbidity were 1.46 (95% CI 1.11-1.92; P = .007) among women 35-39 years and 1.95 (95% CI 1.13-3.35; P = .02) among women 40 years or older. Perinatal mortality rates were low at all ages, especially in recent years. CONCLUSION: Older maternal age is associated with relatively higher risks of perinatal mortality/morbidity, although the absolute rate of such outcomes is low.

Adult↗
PubMed2005

Maternal outcomes in pregnancies complicated by obesity.

OBJECTIVE: To investigate the relationship between prepregnancy obesity and maternal outcomes. METHODS: A 15-year, population-based cohort study using the Nova Scotia Atlee Perinatal Database compared maternal outcomes in obese and nonobese women. Prepregnancy weight of 55-75 kg was considered nonobese, and weight greater than 90 kg was considered obese. Obese women were categorized into moderate obesity (90-120 kg) and severe obesity (> 120 kg) groups. Univariate and multivariable logistic regression analysis was performed, and odds ratios (ORs), adjusted ORs, and 95% confidence intervals (CIs) were calculated. P < .05 was considered statistically significant. RESULTS: In 142,404 singleton pregnancies, 10,134 (7.2%) women were identified as obese (moderate obesity 92.3%, severe obesity 7.7%). The proportion of women in the obese categories increased from 3.2% in 1988 to 10.2% in 2002. Moderately obese women had an increased risk of pregnancy-induced hypertension (PIH) (adjusted OR 2.38, 95% CI 2.24-2.52), antepartum venous thromboembolism (adjusted OR 2.17, 95% CI 1.30-3.63), labor induction (adjusted OR 1.94, 95% CI 1.86-2.04), cesarean delivery (adjusted OR 1.60, 95% CI 1.53-1.67), and wound infection (adjusted OR 1.67, 95% CI 1.38-2.00). Severely obese women had an increased risk of PIH (adjusted OR 3.00, 95% CI 2.49-3.62), antepartum venous thromboembolism (adjusted OR 4.13, 95% CI 1.26-13.54), induction of labor (adjusted OR 2.77, 95% CI 2.39-3.21), cesarean delivery (adjusted OR 2.46, 95% CI 2.15-2.81), anesthesia complications (adjusted OR 2.01, 95% CI 1.33-3.06), and wound infection (adjusted OR 4.79, 95% CI 3.30-6.95). This implies that, relative to nonobese women, there was 1 excess case of PIH per 10 moderately obese women and 1 per 7 severely obese women. For antepartum venous thromboembolism, there was 1 excess case per 857 moderately obese women and 1 per 321 severely obese women. CONCLUSION: Prepregnancy maternal obesity increases the risk of PIH, antepartum venous thromboembolism, labor induction, cesarean delivery, and wound infection.

Adult↗
PubMed2005

Does reducing infant mortality depend on preventing low birthweight? An analysis of temporal trends in the Americas.

Low birthweight (LBW) is highly associated with death during infancy, and countries with the highest LBW rates also have the highest infant mortality rates. We compared temporal trends in LBW with both overall and birthweight-specific infant mortality in United States, Canada, Argentina, Chile, and Uruguay over two time periods, using cohort and cross-sectional analysis of national population-based vital statistics for 1985-89 and 1995-98. Infant mortality diminished substantially (RR = 0.60-0.80 for the later vs. earlier periods) and to a similar degree in all birthweight categories in all five study countries, despite an increase in LBW in the US and Uruguay, minimal changes in Canada and Argentina, and a decrease in Chile. The strength of the (positive) association between LBW and overall infant mortality diminished over the two time periods (from r(s) = +0.80 to +0.25 and RR per SD increase in LBW rate from 2.13 [2.09, 2.17] to 1.76 [1.74, 1.79]). The proportion of infant deaths occurring among LBW infants was negatively correlated with overall infant mortality in both time periods (r(s) = -0.30 and -0.60, RR = 0.68 [0.67, 0.68] and 0.47 [0.46, 0.47]). Developed and less developed countries in the Americas have succeeded in reducing infant mortality in all birthweight groups despite inconsistent changes in LBW rates, and none has achieved this success primarily by reducing LBW. Although our results are not necessarily generalisable to the least developed countries in South Asia and sub-Saharan Africa, it is likely that all countries can substantially reduce their infant mortality rates by improving the care of infants at normal and low birthweights.

Cross-Sectional Studies↗
PubMed2004

A proportional hazards model with time-dependent covariates and time-varying effects for analysis of fetal and infant death.

Birth-weight- and gestational-age-specific perinatal mortality curves intersect when compared by race and maternal smoking. The authors propose a new measure to replace fetal and infant mortality and an analytic strategy to assess the effects of risk factors on this outcome. They used 1998 data for US Blacks and Whites. Age-specific post-last menstrual period (LMP) mortality rate was defined as the proportion of deaths (stillbirth, perinatal death, or infant death) at a given age post-LMP. The authors used extended Cox regression with time-varying covariates and hazard ratios to model the effects of race and smoking on post-LMP mortality. Perinatal mortality rates (conventional calculation) for Blacks and Whites showed the expected crossover. However, analyses of post-LMP mortality showed no crossover. For the Black-White comparison, a hazard ratio of 1.72 (95% confidence interval: 1.67, 1.77) was obtained. The hazard was higher for smokers than for nonsmokers, but the hazard ratio increased from 1.09 (95% confidence interval: 0.98, 1.22) at 22 weeks to 1.82 (95% confidence interval: 1.72, 1.92) at 40 weeks. The hazard ratio associated with birth was also time dependent: higher than 1 for preterm gestation and lower than 1 for term gestation. The increasing adverse effect of smoking with gestational age suggests an accumulating effect of smoking on mortality. Modeling post-LMP mortality eliminates the crossover paradox for race and maternal smoking in a single statistical model.

Birth Weight↗
PubMed2004

Operative vaginal delivery and neonatal and infant adverse outcomes: population based retrospective analysis.

OBJECTIVE: To compare the risk of neonatal and infant adverse outcomes between vacuum and forceps assisted deliveries. DESIGN: Population based study. SETTING: US linked natality and mortality birth cohort file and the New Jersey linked natality, mortality, and hospital discharge summary birth cohort file. PARTICIPANTS: Singleton live births in the United States (n = 11 639 388) and New Jersey (n = 375 351). MAIN OUTCOME MEASURES: Neonatal morbidity and mortality. RESULTS: Neonatal mortality was comparable between vacuum and forceps deliveries in US births (odds ratio 0.94, 95% confidence interval 0.79 to 1.12). Vacuum delivery was associated with a lower risk of birth injuries (0.69, 0.66 to 0.72), neonatal seizures (0.78, 0.68 to 0.90), and need for assisted ventilation (< 30 minutes 0.94, 0.92 to 0.97; > or = 30 minutes 0.92, 0.88 to 0.98). Among births in New Jersey, vacuum extraction was more likely than forceps to be complicated by postpartum haemorrhage (1.22, 1.07 to 1.39) and shoulder dystocia (2.00, 1.62 to 2.48). The risks of intracranial haemorrhage, difficulty with feeding, and retinal haemorrhage were comparable between both modes of delivery. The sequential use of vacuum and forceps was associated with an increased risk of need for mechanical ventilation in the infant and third and fourth degree perineal tears. CONCLUSION: Although vacuum extraction does have risks, it remains a safe alternative to forceps delivery.

Cohort Studies↗
PubMed2004

A parsimonious explanation for intersecting perinatal mortality curves: understanding the effects of race and of maternal smoking.

BACKGROUND: Neonatal mortality rates among black infants are lower than neonatal mortality rates among white infants at birth weights <3000 g, whereas white infants have a survival advantage at higher birth weights. This finding is also observed when birth weight-specific neonatal mortality rates are compared between infants of smokers and non-smokers. We provide a parsimonious explanation for this paradoxical phenomenon. METHODS: We used data on births in the United States in 1997 after excluding those with a birth weight <500 g or a gestational age <22 weeks. Birth weight- and gestational age-specific perinatal mortality rates were calculated per convention (using total live births at each birth weight/gestational age as the denominator) and also using the fetuses at risk of death at each gestational age. RESULTS: Perinatal mortality rates (calculated per convention) were lower among blacks than whites at lower birth weights and at preterm gestational ages, while blacks had higher mortality rates at higher birth weights and later gestational ages. With the fetuses-at-risk approach, mortality curves did not intersect; blacks had higher mortality rates at all gestational ages. Increases in birth rates and (especially) growth-restriction rates presaged gestational age-dependent increases in perinatal mortality. Similar findings were obtained in comparisons of smokers versus nonsmokers. CONCLUSIONS: Formulating perinatal risk based on the fetuses-at-risk approach solves the intersecting perinatal mortality curves paradox; blacks have higher perinatal mortality rates than whites and smokers have higher perinatal mortality rates than nonsmokers at all gestational ages and birth weights.

Journal Article↗
PubMed2004

Incidence-based measures of birth, growth restriction, and death can free perinatal epidemiology from erroneous concepts of risk.

BACKGROUND: Traditional perinatal epidemiology appears to embrace fallacious concepts of risk. The use of incorrect denominators for perinatal rates is commonplace both for straightforward indices such as the gestational age-specific labor induction rate and also for the more conceptually challenging indices such as the gestational age-specific neonatal mortality rate. As a consequence, perinatology is beset by several conondrums including the paradox of intersecting perinatal mortality curves. PROPOSITION: These traditions are ideally replaced by alternative concepts that may be derived a priori and measured using indices such as presented here: the incidence of birth (i.e., the gestational age-specific birth rate), the incidence of growth restriction (i.e., the gestational age-specific growth-restriction rate) and the incidence of death (i.e., the age-specific mortality rate). RESULTS: The incidence of birth, growth restriction, and death quantify the core phenomena in perinatology and reveal congruent and coherent patterns of occurrence. CONCLUSIONS: These new indices can free perinatal epidemiology from erroneous concepts of risk and resolve the paradoxal phenomena that plague the perinatal domain. They also permit the development of a theoretical framework for obstetric intervention, which in recent years has been based exclusively on empirical evidence.

Birth Rate↗
PubMed2004

The influence of hospital closures in Nova Scotia on perinatal outcomes.

OBJECTIVE: To evaluate the effect of hospital closures on critical obstetrical interventions and perinatal outcomes in rural communities in Nova Scotia, Canada. METHODS: A population-based cohort study was carried out for the years 1988 to 2002, using data extracted from the Nova Scotia Atlee Perinatal Database. Regions of maternal residence were defined geographically and administratively as Eastern, Northern,Western, and Central. The time periods of 1988 to 1993 and 1996 to 2002 were chosen based on the timing of hospital closures. Changes in rates of several perinatal outcomes were examined by region in relation to the extent of hospital closures experienced by that region. RESULTS: The majority of hospital closures occurred in 1994 to 1995 with the establishment of new health regions, and affected the Western region most profoundly. In comparison with the Central region (relative risk [RR], 0.56; 95% confidence interval [CI], 0.53-0.59), the temporal reduction in the rate of forceps-assisted vaginal delivery was smaller in the Western region (RR, 0.83; 95% CI, 0.76-0.91; P < .001), but greater in the Northern (RR, 0.36; 95% CI, 0.32-0.41; P < .001) and Eastern (RR, 0.26; 95% CI, 0.23-0.30; P < .001) regions. The temporal increase in the rate of breastfeeding at discharge from hospital was smaller in the Northern region (RR, 1.36; 95% CI, 1.29-1.45; P < .001) compared to that in the Central region (RR, 1.55; 95% CI, 1.49-1.61). The decrease in the rate of fetal growth restriction was smaller in the Western (RR, 0.95; 95% CI, 0.87-1.02; P = .002) and Eastern (RR, 0.90; 95% CI, 0.82-0.98; P = .002) regions of residence compared to the Central region (RR, 0.75; 95% CI, 0.71-0.79). There were no significant regional differences in temporal patterns of preterm induction and/or preterm Caesarean delivery, or perinatal mortality. CONCLUSION: Although trends over time demonstrated some regional differences in obstetrical interventions and perinatal outcomes, our retrospective evaluation did not reveal a consistent relationship between reductions in maternity services associated with hospital closures and systematic, population-level adverse perinatal consequences in Nova Scotia.

Adult↗
PubMed2004

Recent trends in caesarean delivery rates and indications for caesarean delivery in Canada.

OBJECTIVE: To examine recent trends in Caesarean delivery rates as well as the indications for Caesarean delivery in Canada, excluding the provinces of Manitoba and Quebec. METHODS: All deliveries (N = 1 807 388) recorded in the Canadian Institute for Health Information's Discharge Abstract Database for the years 1994/95 to 2000/01 were included in the study (all hospital deliveries in Canada except for those occurring in Manitoba and Quebec). Temporal trends and inter-provincial/territorial variations in Caesarean delivery rates were quantified, and the primary indications for Caesarean delivery during the study period were compared. RESULTS: The overall Caesarean delivery rate increased from 18.0% in 1994/95 to 22.1% in 2000/01. The primary Caesarean delivery rate increased from 12.7% to 16.3%, while the rate of vaginal birth after Caesarean decreased from 33.3% to 28.5% over the same period. Most of the increase in primary Caesarean deliveries was due to increases in Caesarean deliveries for dystocia, which increased from 6.9% in 1994/95 to 9.2% in 2000/01. The largest increase in repeat Caesarean deliveries was due to elective repeat Caesarean sections, which increased from 37.7% to 40.3%. Approximately 15% of the increase in overall Caesarean delivery rates was explained by increases in maternal age. The rate of vaginal deliveries following forceps rotation declined from 1.9% in 1994/95 to 1.3% in 2000/01. CONCLUSION: Most of the recent increase in Caesarean delivery rates in Canada was attributed to increases in primary Caesarean delivery for dystocia and elective repeat Caesarean deliveries.

Adult↗
PubMed2004

The influence of obstetric intervention on trends in twin stillbirths: United States, 1989-99.

OBJECTIVE: Although twin stillbirth rates have declined substantially over the past two decades, the contribution of changes in obstetric interventions to reducing twin stillbirths has not been quantified. METHODS: We carried out a retrospective cohort study of twin live births and stillbirths in the United States between 1989 and 1999 (n=1,102,212). Changes in the rate of stillbirth (> or =22 weeks) before and after adjustment for changes in labor induction, Cesarean delivery and sociodemographic factors were estimated through ecological logistic regression analysis. This analysis was based on aggregating data by each state within the United States. RESULTS: Between 1989 and 1999, rates of labor induction and Cesarean delivery among twin live births increased by 138% (from 5.8% to 13.8%) and 15% (from 48.3% to 55.6%), respectively. These changes were accompanied by a 43% decline in the stillbirth rate between 1989 and 1999 (from 24.4 to 13.9 per 1000 fetuses at risk). After excluding births weighing < 500 g, rates of labor induction among twins at 22-27 weeks', 28-33 weeks' and > or =34 weeks' gestation increased by 95%, 131% and 127%, respectively, between 1989 and 1999. Cesarean delivery rates also increased by 55%, 29% and 2% in these same gestational age categories. The 48% (relative risk (RR) 0.52, 95% confidence interval (CI) 0.49-0.55) decline in stillbirth rate between 1989-91 and 1997-99 was reduced to a 25% (RR 0.75, 95% CI 0.72-0.79) decline after adjustment for changes in labor induction and Cesarean delivery. The decline in the rate of twin stillbirths was larger at later gestational ages (at > or =32 and > or =34 weeks) where the largest absolute increases in labor induction rates were observed. CONCLUSIONS: The use of Cesarean delivery and especially labor induction for twin pregnancies has increased substantially in the United States over the last decade and these changes have been associated with a large decline in the rate of stillbirth among twins.

Adolescent↗
PubMed2004

Sudden infant death syndrome in Canada: trends in rates and risk factors, 1985-1998.

In Canada, sudden infant death syndrome (SIDS) remains the leading cause of postneonatal death. However, SIDS rates have been declining in many countries, including Canada. This decline has been largely attributed to recommendations to avoid placing infants to sleep in the prone position. We examined the postneonatal rate of mortality due to SIDS and to other causes in relation to the initial risk reduction campaign. The postneonatal mortality rate due to SIDS decreased from 0.97 to 0.54 per 1,000 neonatal survivors between 1985-1989 and 1994-1998 (relative risk [RR] = 0.56, 95% confidence interval [CI] 0.51-0.62). The rate of postneonatal mortality due to other causes also decreased during the same period, though to a smaller extent, from 1.19 to 0.86 (RR = 0.72, 95% CI 0.66-0.78). With the exception of seasonality, established risk factors for SIDS remained essentially unchanged between the two time periods. The observed reduction in postneonatal SIDS is consistent with a positive impact of the initial recommendations regarding risk reduction. However, the lack of reliable risk factor data limits the extent to which the decline can be attributed directly to the campaign.

Birth Weight↗
PubMed2003

Does the risk of cerebral palsy increase or decrease with increasing gestational age?

BACKGROUND: It is generally accepted that the risk of cerebral palsy decreases with increasing gestational age of live born infants. However, recent studies have shown that cerebral palsy often has prenatal antecedents including congenital malformations, vascular insults and maternal infection. Cerebral palsy is therefore better viewed as occurring among fetuses, rather than among infants. We explored the epidemiologic implications of this change in perspective. METHODS: We used recently published data from Shiga Prefecture, Japan and from North-East England to examine the pattern of gestational age-specific rates of cerebral palsy under these alternative perspectives. We first calculated gestational age-specific rates of cerebral palsy as per convention, by dividing the number of cases of cerebral palsy identified among live births within any gestational age category by the number of live births in that gestational age category. Under the alternative formulation, we calculated gestational age-specific rates of cerebral palsy by dividing the number of cases of cerebral palsy identified among live births within any gestational age category by the number of fetuses who were at risk of being born at that gestation and being afflicted with cerebral palsy. RESULTS: Under the conventional formulation, cerebral palsy rates decreased with increasing gestational age from 63.9 per 1,000 live births at <28 weeks gestation to 0.9 per 1,000 live births at 37 or more weeks gestation. When fetuses were viewed as potential candidates for cerebral palsy, cerebral palsy rates increased with increasing gestational age from 0.08 per 1,000 fetuses at risk at <28 weeks gestation to 0.9 per 1,000 fetuses at risk at 37 or more weeks gestation. CONCLUSIONS: The fetuses-at-risk approach is the appropriate epidemiologic formulation for calculating the gestational age-specific rate of cerebral palsy from a causal perspective. It shows that the risk of cerebral palsy increases as gestational duration increases. This compelling view of cerebral palsy risk may help refocus research aimed at understanding and preventing cerebral palsy.

Journal Article↗
PubMed2003

Changes in maternal characteristics and obstetric practice and recent increases in primary cesarean delivery.

OBJECTIVE: To estimate the contribution of changes in maternal characteristics (namely, age, parity, prepregnancy weight, weight gain in pregnancy, smoking status) and obstetric practice (namely, labor induction, epidural anesthesia, delivery by an obstetrician, midpelvic forceps delivery) to recent increases in primary cesarean delivery rates. METHODS: We studied all deliveries in Nova Scotia, Canada, between 1988 and 2000 after excluding women who had a previous cesarean delivery (n = 127,564). Logistic regression was used to study the effect of changes in maternal characteristics and obstetric practice on primary cesarean delivery rates. The effect of changes in midpelvic forceps delivery was examined through ecologic Poisson regression. RESULTS: Primary cesarean delivery rates increased from 13.4% of deliveries in 1988 to 17.5% in 2000. This was due to increases in cesarean deliveries for dystocia (14% increase), breech (24% increase), suspected fetal distress (21% increase), hypertension (47% increase), and miscellaneous indications (73% increase). Adjustment for maternal characteristics reduced the temporal increase in primary cesarean delivery rates between 1988-1991 and 1998-2000 from 21% (95% confidence interval [CI] 16%, 25%) to 2% (95% CI -2%, 7%). Additional adjustment for obstetric practice factors further reduced period effects. Midpelvic forceps delivery was significantly and negatively associated with primary cesarean delivery (P =.001). CONCLUSION: Recent increases in primary cesarean delivery rates are a consequence of changes in maternal characteristics. Obstetric practice, which has altered due to changes in maternal characteristics and concerns related to fetal and maternal safety, has also contributed to increases in primary cesarean delivery.

Adult↗
PubMed2003

Trends in major risk factors for anal sphincter lacerations: a 10-year study.

OBJECTIVES: (1) To identify independent risk factors for anal sphincter laceration, (2) to determine the trend in rates of anal sphincter laceration over a 10-year period, and (3) to examine the impact of temporal trends in risk factors on anal sphincter laceration rates. METHODS: Population-based data were obtained from the Nova Scotia Atlee Perinatal Database, on 91 206 women who had a singleton vaginal live birth > or =500 g for the years 1988 to 1997. Risk factors for anal sphincter laceration were identified using stepwise logistic regression. A multivariate model was used to study temporal changes in laceration rates after controlling for changes in parity, episiotomy rates, operative vaginal deliveries, birth weight, prolonged second stage of labour, and other determinants. RESULTS: Nulliparity (relative risk [RR] = 6.97), occiput posterior position (RR = 2.44), non-vertex presentations (RR = 2.27), second stage > or =120 min (RR range = 1.47-2.02), delivery by an obstetrician (RR = 1.30), and birth weight > or =3000 g (RR range = 1.43-6.63) increased the risk of laceration. Instrument-assisted delivery involved risks that ranged from a 2-fold increase for a vacuum-assisted delivery (RR = 2.15) to a greater than 5-fold increase for a forceps delivery after an unsuccessful vacuum extraction (RR = 5.69). Episiotomy, particularly midline incisions, increased the risk of laceration (RR = 2.57). The risk of a sphincter laceration increased 2-fold from 1988 to 1997, despite controlling for risk factors. CONCLUSIONS: Sufficient evidence exists about the risk factors for anal sphincter laceration to permit modification of management of labour and delivery to minimize the risk of anal sphincter laceration. Increased awareness of the clinical importance of recognition and repair of anal sphincter laceration may explain the rising incidence.

Adult↗
PubMed2003

Secular trends of fetal growth in Canada, 1981 to 1997.

Preterm birth and low birthweight in Canada have shown paradoxical temporal trends, with an increase in preterm birth and a decrease in low birthweight. Mean birthweight has increased in many industrialised countries, despite a recent rise in preterm birth, suggesting a temporal increase in fetal growth (birthweight for gestational age) in Canada. We thus described temporal trends in the distribution of fetal growth from 1981 to 1997, including means and proportions of infants at both the low and high ends of the fetal growth distribution. We used data for singleton live births from Statistics Canada's Canadian Birth Data Base for the years 1981-97 (excluding Ontario and Newfoundland) and analysed temporal trends in birthweight and birthweight-for-gestational-age z-score as continuous outcomes and the derived dichotomised outcomes [i.e. low birthweight (<2500 g), very low birthweight (<1500 g), small-for-gestational-age (<10th percentile), very small-for-gestational-age (<3rd percentile), high birthweight (>4000 g), very high birthweight (>4500 g), large-for-gestational-age (>90th percentile), and very large-for-gestational-age (>97th percentile)]. The birthweight-for-gestational-age was based on a newly developed population-based Canadian reference. The results showed that in the overall sample and in a subsample of term and post-term births, mean birthweight, mean z-score, rates of high birthweight, very high birthweight, large-for-gestational-age, and very large-for-gestational-age increased whereas rates of low birthweight, very low birthweight, small-for-gestational-age, and very small-for-gestational-age decreased between 1981-83 and 1995-97. The reverse was observed in preterm births. These temporal changes were larger for more extremely distributed measures of fetal growth. For example, compared with 1981-83, the decrease in 1995-97 for very small-for-gestational-age (<3rd percentile) was 38.9%, whereas the decrease for small-for-gestational-age (<10th percentile) was only 29.7%. Corresponding temporal increases were 21.4% for very large-for-gestational-age (>97th percentile) and 15.2% for large-for-gestational-age (>90th percentile). Among infants with gestational age 34-36 weeks, all measures of fetal growth, including the rates for all dichotomous outcomes, decreased in 1995-97 as compared with 1981-83. We conclude that Canadian infants are getting bigger, but only those born at term. The temporal trends for more extremely distributed fetal growth measures are particularly marked.

Adult↗
PubMed2002

Analysis of perinatal mortality and its components: time for a change?

Since the midtwentieth century, stillbirths (late fetal deaths) and early neonatal deaths have often been combined into a single category of "perinatal" deaths. In the past, such a combination was justified by the fact that asphyxia was a common cause of death during labor (intrapartum stillbirth) and shortly after birth and by geographic and temporal differences in classification of livebirths versus stillbirths. In more recent years, however, the etiologic determinants have diverged sharply, with many fewer early neonatal deaths caused by asphyxia and relatively many more caused by congenital anomalies. Moreover, the increasingly common stratification of pregnancy outcome measures by gestational age or birth weight leads to the use of an inappropriate denominator (total livebirths plus stillbirths within each gestational age or birth weight category) for denoting risk for the stillbirth component, because all unborn fetuses (including the majority of those not born within the specified gestational age or birth weight range) are at risk of being stillborn in that range. The authors suggest that, whenever possible, stillbirths and early neonatal deaths should be reported separately, with gestational age-specific risks of stillbirth based on all fetuses at risk, and that antepartum and intrapartum stillbirths be reported separately.

Adult↗