Ethnicity and birth outcome: New Zealand trends 1980-2001: Part 4. Pregnancy outcomes for European/other women

BACKGROUND: In the early 1980s European/other women made up 80% of New Zealand's population and experienced rates of preterm birth that were lower than for other ethnic groups. Rates of small for gestational age (SGA) and late fetal death were intermediate between those of Maori and Pacific women. AIMS: To examine trends in preterm birth, SGA and late fetal death for European/other women during 1980-2001 and to explore risk factors which make this group vulnerable to adverse birth outcome. METHODS: De-identified birth registration data from 1 189 120 singleton live births and 5775 stillbirths were analysed for 1980-2001. Outcomes of interest included preterm birth, SGA and late fetal death while explanatory variables included maternal ethnicity, age and NZ Deprivation Index decile. Trend analysis was undertaken for 1980-1994 and multivariate logistic regression was used to explore risk factors for 1996-2001. RESULTS: During 1980-1994, rates of preterm birth rose by 30% for European/other women, in contrast to a non-significant decline of 7% for Maori women and 4% for Pacific women. Rates of SGA declined 19% for European/other women, compared to 25% for Maori and 30% for Pacific women. Preterm birth and SGA were positively associated with teenage pregnancy and increasing NZDep deprivation. During 1980-1994, rates of late fetal death declined by 49%, with declines being similar for all ethnic groups. CONCLUSIONS: The progressive rise in preterm birth during the past two decades is a cause of concern for European/other women, particularly as it appears confined to this ethnic group. While rates of SGA have declined, albeit at a slower rate than for other ethnic groups, the elevated risk amongst teenagers and those living in the more deprived NZDep areas suggests that greater gains are achievable if interventions are targeted towards these particular groups.     

Ethnicity and birth outcome: New Zealand trends 1980-2001: Part 2. Pregnancy outcomes for Maori women

BACKGROUND: While traditionally Maori perinatal mortality has been similar to that of other ethnic groups, rates of preterm birth, small for gestational age (SGA) and teenage pregnancy have remained high. AIMS: To review current trends in preterm birth, SGA and teenage pregnancy for Maori during 1980-2001 and to highlight the major factors that have influenced Maori reproductive outcomes during this period. METHODS: De-identified birth registration data from 1 189 120 singleton live births and 5775 stillbirths were analysed for 1980-2001. Outcomes of interest included preterm birth, SGA and late fetal death while explanatory variables included maternal ethnicity, age and NZ Deprivation Index decile. Trend analysis was undertaken for 1980-1994 and multivariate logistic regression was used to explore risk factors for 1996-2001. RESULTS: During 1980-1994, Maori women had the highest preterm birth rates of any ethnic group in New Zealand, but in relative terms, inequalities declined as a consequence of a non-significant 7% fall in rates being offset by a statistically significant 30% increase for the European/other ethnic group. Rates of SGA were also higher amongst Maori women but declined by 25% during the 1980-1994 period. In addition, Maori women experienced significant socioeconomic gradients in SGA, with risk for Maori women in the most deprived NZDep areas being double that of Maori living affluent areas. Paradoxically, while Maori women had high rates of teenage pregnancy, this did not confer additional risk for preterm birth or SGA during the 1996-2001 period. CONCLUSIONS: While high rates of teenage pregnancy amongst Maori women appear not to confer additional risk for preterm birth or SGA, the social consequences of early childbearing may well be significant. The persistence of elevated rates of preterm birth and large socioeconomic gradients in SGA amongst Maori suggest that broader social and policy interventions are necessary if Maori are to achieve optimal birth outcomes in the coming decades.     

Ethnicity and birth outcome: New Zealand trends 1980-2001: Part 3. Pregnancy outcomes for Pacific women

BACKGROUND: Pacific women in New Zealand reside in areas of higher socioeconomic deprivation compared to women from other ethnic groups. Pacific women and their health are further disadvantaged because of genetic predisposition and sociocultural factors that cause ill-health. The correlations between pregnancy outcomes, risk factors and other health indices in Pacific women need evaluation. AIMS: To examine trends in preterm birth, small for gestational age (SGA) and late fetal death for Pacific women during 1980-2001 and to explore risk factors which make this group vulnerable to adverse birth outcome. METHODS: De-identified birth registration data from 1 189 120 singleton live births and 5775 stillbirths were analysed for 1980-2001. Outcomes of interest included preterm birth, SGA and late fetal death while explanatory variables included maternal ethnicity, age and NZ Deprivation Index decile. Trend analysis was undertaken for 1980-1994 and multivariate logistic regression was used to explore risk factors for 1996-2001. RESULTS: Pacific women had the lowest rates of preterm birth and SGA when compared to Maori and European women. In addition, preterm birth rates underwent a non-significant 4% decline and SGA rates a 30% decline during 1980-1994. Although there has been a 49% decline in late fetal deaths during 1980-1994, the rate remained higher for Pacific women than for Maori and European/other women. CONCLUSIONS: Despite residing in areas of high socioeconomic deprivation, which is associated with poor pregnancy outcomes for Maori and European/other women, Pacific women had better pregnancy outcomes, with lower preterm and SGA rates. The significant decline in rates of late fetal death during the past two decades is a cause for celebration; however, the rate remains higher for Pacific women than for other ethnic groups. Biological, cultural and social factors might explain the better pregnancy outcomes for Pacific women and these factors should be considered when developing future prevention programmes.     

Causes of late fetal death in New Zealand 1980-1999

BACKGROUND: In recent years there has been an emerging interest in sudden unexplained intrauterine death. Aims: To determine the major causes of late fetal death (LFD) in New Zealand during 1980-1999 and to document the proportion of deaths considered unexplained. In addition, to quantify the number of LFD undergoing post-mortem during this period. METHODS: Using the Office for National Statistics (UK) hierarchical classification system, all information available on death certificates was used to assign a single cause to LFD for the period 1980-1999. Trends were analysed using logistic regression and risk factor profiles established for each cause of death. Post-mortem rates and the characteristics of those failing to undergo post-mortem were analysed for the period 1989-1999. RESULTS: LFD rates declined from 60.1 per 10 000 in 1980-1981 to 30.5 in 1998-1999. The declines were not uniform across all causes, with intrapartum deaths declining 73%, congenital anomalies 70% and antepartum asphyxia 50%. In contrast, unspecified deaths increased 1%, and with the decline in other causes of death, also increased proportionally, from 10.8% of LFD in 1980-81 to 28.1% in 1998-1999. Post-mortem rates fell by 31% during 1989-1999, with Maori and Pacific babies and those in more deprived New Zealand Deprivation Index areas being significantly less likely to undergo post-mortem. CONCLUSIONS: While total LFD rates declined significantly during 1980-1999, rates of unspecified LFD remained static. Low post-mortem rates, however, suggest that many of these deaths may be uninvestigated rather than truly unexplained. Nevertheless, the persistence of a category of death which, to date, has failed to improve with advances in obstetric technology suggests that further measures are necessary if New Zealand's LFD rates are to continue to decline.     

Low first-trimester hemoglobin and low birth weight, preterm birth and small for gestational age newborns.

OBJECTIVE: To examine the relationship between first-trimester hemoglobin (Hb) concentration and risk of low birth weight (LBW), preterm birth and small for gestational age (SGA). METHODS: Data were obtained from a population-based prenatal care program in China. A total of 88,149 women who delivered during 1995-2000 and had their Hb measured in the first trimester were selected as study subjects. RESULTS: The prevalence of anemia (Hb<110 g/L) was 22.1% in the first trimester. The risk of LBW, preterm birth and SGA was increased steadily with the decrease of first-trimester Hb concentration. After controlling for confounding factors, women with Hb 80-99 g/L had significantly higher risk for LBW (OR=1.44, 95% CI 1.17-1.78), preterm birth (OR=1.34, 95% CI 1.16-1.55) and SGA (OR=1.13, 95% CI 0.98-1.31) than women with Hb 100-119 g/L. No elevated risk was noted for women with Hb> or =120 g/L. CONCLUSION: Low first-trimester Hb concentration increases the risk of LBW, preterm birth and SGA.     

Preterm birth in Sweden 1973-2001: rate, subgroups, and effect of changing patterns in multiple births, maternal age, and smoking

BACKGROUND: The objectives of this report are to evaluate changes in the preterm birth rate in Sweden 1973-2001. Furthermore, describe the proportion of spontaneous and indicated preterm births and assess risk factors for the subgroups of preterm birth during the period from 1991 to 2001. METHODS: A population-based register study of all births occurring in Sweden from 1973 to 2001 registered in the Swedish Medical Birth Register was designed. The analysis of subgroups was restricted to the period 1991-2001. Gestational age was calculated using last menstrual period and best estimate. Odds ratio for preterm birth related to risk factors was calculated for the subgroups' spontaneous and indicated preterm birth. RESULTS: After an increase in the beginning of the 1980s, the preterm birth rate has decreased from 6.3% in 1984 to 5.6% in 2001 (P < 0.0001). The proportion of multiple births born preterm of the total birth rate increased from 0.34% in 1973 to 0.71% in 2001 (P < 0.0001). Spontaneous preterm births account for 55.2% and iatrogenic preterm births for 20.2% of all preterm births. The strongest association with maternal smoking in early pregnancy was found at gestational age <28 weeks and spontaneous preterm birth [odds ratio (OR) smoking versus no smoking: 1.55, 95% confidence intervals (CI): 1.42-1.69]. The strongest association for maternal age was found between gestational age <28 weeks and indicated preterm birth (OR 5-year increase: 1.34, 95% CI: 1.21-1.47). CONCLUSIONS: The preterm birth rate in Sweden has decreased since the mid 1980s. The composition of different subtypes of preterm birth in a Scandinavian low-risk population seems to be similar to populations with higher incidence of preterm birth and perinatal infections.     

Term birthweight centiles for babies from New Zealand's main ethnic groups

BACKGROUND: There are significant differences in mean birthweights between New Zealand's main ethnic groups. Birthweight centiles developed predominantly from babies of European ethnicity may therefore not be appropriate to classify babies from other ethnic groups. AIMS: To develop ethnic specific birthweight centiles for New Zealand babies delivered at term (>37 weeks). METHODS: Births from the National Women's Hospital database from 1993 to 2000 who also had scan data at <24 weeks comprised the study population (n = 10 292). Multiple pregnancies, fetal abnormalities, stillbirths and preterm births were excluded. For six ethnic groupings, born at gestational weeks from 38 to 41, sex specific centiles were generated and smoothed. RESULTS: Birthweight centiles were constructed from 5203 European, 801 Maori, 825 Samoan, 577 Tongan, 1058 Chinese, 433 Indian and 1395 other ethnic group births. Mean birthweights by ethnic group were: European 3521 g, Maori 3467 g, Samoan 3691 g, Tongan 3791 g, Chinese 3418 g, Indian 3192 g and other 3466 g. Tongan and Samoan babies were significantly heavier and Indian babies were significantly lighter than babies from all other ethnic groups (P < 0.001 for all comparisons). Overall Maori babies were approximately 50 g lighter than European babies but this difference was not statistically significant (P = 0.08), whereas Chinese babies were significantly lighter with a mean birthweight 100 g less than European (P < 0.001). CONCLUSIONS: These ethnic specific centile charts are likely to identify term babies with inappropriate growth better than population centiles generated predominantly from one ethnic group.     

Teenage pregnancies and risk of late fetal death and infant mortality.

OBJECTIVE: To estimate the effect of low maternal age on late fetal death and infant mortality and to estimate the extent of any increase in infant mortality attributable to higher rates of preterm birth among teenagers. DESIGN: Population-based cohort study. SETTING: Births recorded in the nationwide Swedish Medical Birth Registry. POPULATION: All single births to nulliparous women aged 13-24 years (n = 320,174) during 1973-1989. METHODS: Using information recorded in the medical birth registry, linked to a national education register, the effect of low maternal age on adverse outcomes was estimated using logistic regression analysis. MAIN OUTCOME MEASURES: Late fetal death, neonatal and postneonatal mortality and preterm birth. RESULTS: Compared with mothers aged 20-24 years, adjusted risks of neonatal and postneonatal mortality were significantly increased among mothers aged 13-15 years (odds ratios = 2.7 and 2.6, respectively) and among those aged 16-17 years (odds ratios = 1.4 and 2.0, respectively), while mothers aged 18-19 years had a significant increase in risk of postneonatal mortality only (odds ratio = 1.4). Rates of very preterm birth (< or = 32 weeks), according to maternal age, were: 13-15 years, 5.9%; 16-17 years, 2.5%; 18-19 years, 1.7%; and 20-24 years, 1.1%. The high rates of very preterm birth among young teenagers almost entirely explained the increased risk of neonatal mortality in this group. CONCLUSIONS: The increased risks of neonatal and postneonatal mortality among young teenagers may be related to biological immaturity. The increase in risk of neonatal mortality is largely explained by increased rates of very preterm birth.     

New-onset hypertension in late pregnancy and fetal growth: different associations between singletons and twins.

OBJECTIVE: To compare the effects of new-onset hypertension (NOH) in late pregnancy on fetal growth in singletons and twins. METHODS: A retrospective cohort study was conducted to evaluate the effect of NOH on fetal growth in 17, 720, 900 singletons and 463, 104 twins born in the United States between 1995 and 2000. RESULTS: NOH was associated with lower mean birth weight in both preterm and term singletons. Increased risk of low birth weight and decreased risk of high birth weight was associated with NOH in preterm and term singletons. NOH was associated with increased risk for small-for-gestational-age (SGA) births and decreased risk for large-for-gestational-age (LGA) births in preterm singletons, whereas it was associated with increased risk of both SGA and LGA births in term singletons. NOH was associated with higher mean birth weight in early preterm twins, and lower mean birth weight in term twins. Decreased risk for low birth weight was found in the NOH group among early preterm twins, and increased risk for low birth weight in term twins. NOH was associated with increased risk of SGA births and decreased risk for large-for-gestational-age (LGA) births in early preterm twins, while increased risk of SGA births in term twins. CONCLUSION: NOH is associated with slower fetal growth in singletons delivered at different gestational ages, but the effect varies in twins depending on gestational age at delivery with faster growth in early preterm twins.     

Causes and consequences of recent increases in preterm birth among twins.

OBJECTIVE: To examine the causes and consequences of the recent increase in preterm birth among twins. METHODS: We studied all twin births among residents of the province of Nova Scotia, Canada, between 1988 and 1997. Rates of preterm birth, preterm labor induction, preterm cesarean, small-for-gestational age (SGA), respiratory distress syndrome (RDS), stillbirth, perinatal mortality, and infant mortality were compared between past and more recent years. Changes in perinatal mortality were examined using logistic regression to adjust for the effects of other determinants. RESULTS: The study included 2516 twin births (73 stillbirths and 2443 live births). The rate of preterm birth increased from 42.3% in 1988-1992 to 48.2% of twin live births in 1993-1997 (14% increase, P =.04). Twin live births born after preterm labor induction increased from 3.5% in 1988-1989 to 8.6% in 1996-1997 (P for trend =.007). Of live births between 34 and 36 weeks' gestation, the proportion born SGA decreased from 17.5% in 1988-1992 to 9.2% in 1993-1997 (P =.005). Over the same period, rates of prophylactic maternal steroid therapy increased substantially and rates of RDS declined. Perinatal mortality rates among pregnancies reaching 34 weeks decreased from 12.9 per 1000 total births in 1988-1992 to 4.2 per 1000 total births in 1993-1997 (P =.05). CONCLUSION: Increases in preterm labor induction appear to be responsible for the recent increase in preterm birth among twins. These changes have been accompanied by decreases in perinatal morbidity and mortality among twin pregnancies that reach 34 weeks' gestation.     

Intergenerational effects of preterm birth and reduced intrauterine growth: a population-based study of Swedish mother-offspring pairs

OBJECTIVE: To estimate the intergenerational effects of preterm birth and reduced intrauterine growth. DESIGN: Population-based cohort study. SETTINGS: Mother-first-born offspring pairs recorded in the Swedish Medical Birth Registry. POPULATION: Children born before 2001 to 38 720 women born in 1973-75. METHODS: The relationships between the mother's and the child's birth characteristics were estimated using logistic regression analysis. Adjustments were made for smoking habits, body mass index (BMI), and current and childhood socio-economic conditions. Analyses were performed on all mother-offspring pairs and on the pairs for which information on neither of the included background variables was missing (n= 24 520). MAIN OUTCOME MEASURES: Preterm birth (<37 weeks of gestation) and small for gestational age (SGA) (<-2 SD of the Swedish standard). RESULTS: Mothers who themselves had been born preterm were not significantly more likely to deliver their own children preterm, compared with those who had been born at term (adjusted OR 1.24, 95% CI 0.95-1.62). Also, preterm birth in the mothers did not influence the occurrence of SGA in the children. However, the odds ratio for giving birth to SGA and preterm children, respectively, was higher among SGA mothers (OR 2.68, 95% CI 2.11-3.41 and OR 1.30, 95% CI 1.05-1.61). Mothers whose intrauterine growth was moderately reduced but who did not meet the criterion of being born SGA were also at higher risk of giving birth to both preterm and SGA children, respectively. CONCLUSIONS: The present study showed evidence of intergenerational effects of reduced intrauterine growth even when socio-economic factors as well as BMI and smoking were adjusted for. There was, however, no consistent intergenerational effect of preterm birth.     

Bacterial vaginosis in early pregnancy is associated with low birth weight and small for gestational age, but not with spontaneous preterm birth: a population-based study on Danish women.

OBJECTIVE: To analyze the association between bacterial vaginosis (BV) in early pregnancy and preterm birth, low birth weight (LBW) and small for gestational age (SGA) in a Danish population. METHODS: A geographically defined population-based prospective study of Danish-speaking pregnant women over18 years of age enrolled before week 24 and followed until delivery. BV was diagnosed by Amsel's clinical criteria at enrolment. RESULTS: At enrolment, 13.7% had BV. BV was not associated with an increased risk of spontaneous preterm birth (crude OR 0.8 (0.5-1.5)). Nulliparity was found to affect birth weight to such a degree that this variable was used for stratification. In nulliparous women BV was associated with LBW (adj. OR 4.3 (1.5-12)) and SGA (adj. OR 1.6 (0.7-3.1)) compared to nulliparous without BV. No such associations were seen for multiparous women with BV. CONCLUSIONS: BV was not associated with spontaneous preterm birth, but was associated with both LBW and SGA in nulliparous women.     

The joint effect of vaginal Ureaplasma urealyticum and bacterial vaginosis on adverse pregnancy outcomes

OBJECTIVE: To examine associations of vaginal Ureaplasma urealyticum (UU) and bacterial vaginosis (BV) with preterm delivery (PTD), small for gestational age (SGA), and low birth weight (LBW). MATERIAL AND METHODS: A population-based, prospective cohort study of 2,927 pregnancies. After exclusion of multiples and antibiotic use sample size was 2,662. BV (Amsel's criteria) and UU (culture) were assessed in week 17. Gestational age was determined by last menstrual period, confirmed by ultrasound measurement in 97.5%. SGA infants were calculated from intrauterine fetal growth measurements. RESULTS: There was no increased risk for spontaneous PTD among women with BV only (crude odds ratio 1.0, 95% CI 0.4-2.7), among women with UU only (1.3, 0.8-2.0), nor among women with UU + BV (0.9, 0.4-2.3) compared to women without UU and BV. However, there was a threefold increased risk of a LBW birth in women with UU + BV (3.1, 1.8-5.4), a twofold risk of a LBW birth among women with UU only (1.9, 1.3-2.9), but no increased risk among women with BV only (0.8, 0.3-2.2). Similarly, women with UU + BV had over a twofold increased risk of an SGA birth (2.3, 1.3-4.0), women with UU only had a 70% increase (1.7, 1.1-2.5), whereas a nonsignificant increase was found in women with BV only (1.3, 0.6-2.9). Adjustment by established confounders (smoking, previous PTD, previous LBW, and Escherichia coli) did not affect risk estimates. CONCLUSION: This analysis suggests that UU is independently associated with fetal growth and LBW and that BV with UU may enhance the risk of these outcomes.     

Hypertension during pregnancy in South Australia, part 2: risk factors for adverse maternal and/or perinatal outcome - results of multivariable analysis

OBJECTIVE: To identify factors associated with adverse pregnancy outcomes among women with hypertension during pregnancy. DESIGN: A population-based retrospective multivariable analysis using the South Australian perinatal data collection. METHODS: Perinatal data on 70,386 singleton births in 1998-2001 were used in multivariable analyses on three groups: all women combined, all hypertensive women and women with pregnancy hypertension only, in order to identify independent risk factors for requirement for level II/III care, preterm birth, small for gestational age (SGA) birth and maternal length of stay greater than 7 days. RESULTS: The risks for the four morbidities were all increased among women with hypertension compared with normotensive women. Those with pre-existing hypertension had the lowest risk (with odds ratios (OR) 1.26-2.90). Pregnancy hypertension held the intermediate position (OR 1.52-5.70), while superimposed pre-eclampsia was associated with the highest risk (OR 2.00-8.75). Among women with hypertension, Aboriginality, older maternal age, nulliparity and pre-existing or gestational diabetes increased the risk for level II/III nursery care, preterm birth and prolonged hospital stay. Smokers had shorter stays, which may be related to their decreased risk of having a Caesarean section or operative vaginal delivery. Asian women, Aboriginal women, smokers and unemployed women had an increased risk for having an SGA baby, while women with pre-existing or gestational diabetes had a reduced risk. CONCLUSIONS: Among hypertensive pregnant women, nulliparity, older maternal age, Aboriginality, unemployment and diabetes are independent risk factors for one or more major adverse pregnancy outcomes. Smoking does not always worsen the outcome for hypertensive women except for SGA births.     

Race and ethnic disparities in fetal mortality, preterm birth, and infant mortality in the United States: an overview

Infant mortality, fetal mortality, and preterm birth all represent important health challenges that have shown little recent improvement. The rate of decrease in both fetal and infant mortality has slowed in recent years, with little decrease since 2000 for infant mortality, and no significant decrease from 2003 to 2005 for fetal mortality. The percentage of preterm births increased by 36% from 1984 to 2006, and then decreased by 4% from 2006 to 2008. There are substantial race and ethnic disparities in fetal and infant mortality and preterm birth, with non-Hispanic black women at greatest risk of unfavorable birth outcomes, followed by American Indian and Puerto Rican women. Infant mortality, fetal mortality, and preterm birth are multifactorial and interrelated problems with similarities in etiology, risk factors and disease pathways. Preterm birth prevention is critical to lowering the infant mortality rate, and to reducing race and ethnic disparities in infant mortality.     

Teenage pregnancy and ethnicity in The Netherlands: frequency and obstetric outcome.

OBJECTIVES: To study differences in frequency and obstetric outcome of teenage pregnancy (not ending in induced abortion) between the main ethnic groups in The Netherlands. DESIGN: A retrospective cohort study based on the 1990-93 birth cohort in the National Obstetric Registry. SUBJECTS: A total of 10,583 teenagers and 54,501 20-24-year-old women who had a singleton pregnancy and were primiparous. MAIN OBSTETRIC OUTCOME MEASURES: These were perinatal death occurring between the 16th week of pregnancy and 24 h after birth, preterm birth and operative delivery (vaginal extraction and Cesarean section). METHOD: Comparison of the frequency of teenage pregnancy between ethnic groups and by bivariate and multivariate analysis of the three outcome measures between the teenage groups, the teenage groups and ethnically related 20-24-year-old women, and the teenage groups and Dutch 22-24-year-old women. RESULTS: A total of 55.2% of pregnant teenagers had non-Dutch ethnicity compared to 13.8% of all pregnant women. Islamic-Mediterranean teenagers constituted the largest group, one in four of all primiparous Mediterranean women being younger than 20 years of age, followed by black teenagers. Except for Hindustani teenagers, perinatal death occurred in all non-Dutch teenage groups more frequently than in Dutch teenagers, but the differences were only significant for black teenagers (odds ratios of black compared to Dutch teenagers were 2.89 (95% confidence interval (CI) 1.89-4.4) and 1.53 (95% CI 1.19-1.98), respectively). Rates for preterm birth were higher in black and Asian than in Dutch teenagers, but the difference was only significant for black teenagers (odds ratio 1.53, 95% CI 1.19-1.98). Compared to ethnically related 20-24-year-old women, rates of perinatal death and preterm birth were significantly higher in Dutch, black and Asian teenagers and, for preterm birth only, in Mediterranean teenagers. Correction for preterm birth showed that only part of these differences in perinatal death could be explained by preterm birth. Vaginal extraction and Cesarean section occurred less frequently in teenagers than in ethnically related (and in Dutch) 20-24-year-old women. Mediterranean teenagers had the lowest Cesarean section rate and Blacks the lowest vaginal extraction rate. CONCLUSION: Teenage pregnancy in The Netherlands is much more common in minority ethnic groups than in the indigenous population, particularly among Islamic-Mediterraneans and Blacks. Obstetric outcomes vary considerably, these being best in Hindustani and poorest in black teenagers, and being worse in teenagers than in 20-24-year-old women. However, teenagers less often had assisted delivery.     

The impact of ethnicity on the presentation of polycystic ovarian syndrome

The effect of ethnicity on the prevalence and presentation of polycystic ovarian syndrome (PCOS) was examined in a cross-sectional study of women with clinical - and ultrasound - diagnosed PCOS. European, Maori and Pacific Island women were seen in proportion to the general population, whereas Indian women were over-represented and Chinese women under-represented. European and Maori women were more likely to present with hirsutism than other ethnic groups (43% versus 25%, p < 0.05), while European women were less likely to present with infertility (46% versus 68%, p < 0.01). The Pacific Island women had little or no acne but other signs of PCOS were similar among ethnic groups. Although less than 10% of patients were referred with obesity, the majority of PCOS women were overweight on examination. Maori and Pacific Island women were more obese and had the highest rates of insulin resistance and lipid abnormalities. The adverse metabolic profile of many of these women, particularly the Maori and Pacific Islanders, is very likely to predispose them to early cardiovascular disease.     

Trends in fetal growth among singleton gestations in the United States and Canada, 1985 through 1998

We examined trends in fetal growth among singleton live births in the United States and Canada. The data files (n = 48,637,680; 16.6% blacks) for US births, and the Canadian Birth Database of Statistics Canada (n = 3,167,702) for Canadian births were used. Trends were assessed between 1985-86 and 1997-98 with reference to mean birthweight, birthweight-for-gestational-age z-score, and proportions delivered low birthweight (< 2,500 g), small for gestational age (SGA: birthweight < 10th centile for gestational age) and large for gestational age (LGA: birthweight > 90th centile). The term "mean birth weight" increased in the US and Canada between 1985 and 1998, as have the mean z-score. Rates of term SGA births declined among US (11% among whites and 12% among blacks) and Canadian births (27%). Preterm SGA births increased by 3% and 17%, respectively, among US whites and blacks, but declined by 11% among Canadian births. Further, term LGA births increased in the US (5% among whites and 9% among blacks) and Canada (24%). Preterm LGA births declined by 13%, 25%, and 14% among US whites and blacks, and Canadian births, respectively. These findings suggest that US and Canadian babies are getting bigger. The role of preterm obstetrical induction and preterm cesarean delivery are likely to have influenced these trends.     

Parity effect on preterm birth and growth outcomes among infants with isolated omphalocele

OBJECTIVE: To assess the association between parity and fetal morbidity outcomes among omphalocele-affected fetuses. STUDY DESIGN: We carried out a retrospective study of 498 cases of isolated omphalocele (210 born to nulliparous and 288 to multiparous mothers) in New York State from 1983 through 1999. Infants of nulliparous mothers were compared to those of multiparous gravidas using adjusted odds ratios generated from a logistic regression. RESULTS: Omphalocele-affected fetuses of nulliparous mothers had a lower risk of being delivered preterm (odds ratio (OR)=0.49; 95% CI=0.27-0.90) but comparable risks for low birth weight (OR=1.01; 95% CI=0.60-1.72), very low birth weight (OR=0.33; 95% CI=0.09-1.20), very preterm birth (OR=0.42; 95% CI=0.15-1.16), and small size for gestational age (SGA) [OR=0.61; 95% CI=0.23-1.63]. CONCLUSION: Omphalocele-affected fetuses of multiparous mothers have double the risk for preterm birth compared to their nulliparous counterparts. This information is potentially useful in counseling parents whose fetuses have omphaloceles.     

Low Birth-weight in NSW, 1987: a Population-based Study

Summary: The New South Wales perinatal data collection was used to examine the association between low birth-weight and some of its potential risk factors. The study population comprised all recorded singleton births to residents of NSW in 1987. Low birth-weight infants were categorized as either small for gestational age (SGA) or preterm (less than 37 weeks). Risk factors were analyzed separately for these categories. The risk factors examined were primarily demographic or reproductive history variables. Univariate analysis and multivariate logistic regression were used to evaluate the risk factors. The factors associated with SGA birth were mainly demographic (maternal age, parity, marital status, socioeconomic status, and ethnic group) while those associated with preterm birth had more reproductive history variables (maternal age, parity, marital status, prior spontaneous abortion, prior induced abortion, prior stillbirth or neonatal death, sex of infant). A first antenatal visit after 12 weeks had a statistically significant but small effect on both SGA and preterm birth.