Changing risks of stillbirth and neonatal mortality associated with maternal age in Western Australia 1984-2003

Does Advanced Maternal Age Comprise an Independent Risk Factor for Caesarean Section? A Population-Wide Study

OBJECTIVE

To investigate the association between a mother's age and the risk of caesarean section (CS) when controlling for health factors and selected sociodemographic characteristics.

METHODS

Binary logistic regression models for all women who gave birth in Czechia in 2018 (N = 111,749 mothers who gave birth to 113,234 children).

RESULTS

An increase in the age of a mother significantly increases the odds of a CS birth according to all of the models; depending on the model, OR: 1.62 (95% CI 1.54-1.71) to 1.84 (95% CI 1.70-1.99) for age group 35-39 and OR: 2.83 (95% CI 2.60-3.08) to 3.71 (95% CI 3.23-4.27) for age group 40+ compared to age group 25-29. This strong association between the age of a mother and the risk of CS is further reinforced for primiparas (probability of a CS: 11% for age category ≤ 19, 23% for age category 35-39, and 38% for age category 40+). However, the increasing educational attainment of young women appears to have weakened the influence of increasing maternal age on the overall share of CS births; depending on the model, OR: 0.86 (95% CI 0.80-0.91) to 0.87 (95% CI 0.83-0.91) for tertiary-educated compared to secondary-educated women.

CONCLUSIONS

The age of a mother comprises an independent risk factor for a CS birth when the influence of health, socioeconomic, and demographic characteristics is considered.

Epidemiology of stillbirths based on different gestational thresholds at a tertiary hospital

INTRODUCTION

The stillbirth rate (SBR) is an important public health indicator. We studied the distribution of maternal and fetal characteristics and time trends of the SBR at KK Women's and Children's Hospital (KKH), Singapore, from 2004 to 2016 based on various definitions of stillbirth.

METHODS

Data was obtained from the Data Warehouse and Stillbirth Reporting System of KKH from 2004 to 2016. SBRs were calculated based on three definitions (fetal deaths at ≥ 20 weeks, 24 weeks or 28 weeks of gestation per 1,000 total births) and were described with maternal and fetal characteristics, and by year.

RESULTS

From 2004 to 2016, the SBR declined by 44.7%, 25.5% and 18.9% based on Definitions I, II and III, respectively. The SBR at KKH in 2016 was 5.2 (Definition I), 4.1 (Definition II) and 3.0 (Definition III) per 1,000 total births. The SBR was significantly higher in women aged ≥ 35 years, nulliparas and female fetuses. The number of live births at 24-27+6 weeks of gestation was more than four times higher than that of stillbirths (822 vs. 176). There were 104 (12.7%) neonatal deaths during this gestation period, giving a high survival rate of 87.3%.

CONCLUSION

The SBR in KKH is relatively lower than that in other developed countries. There is a need to consider revising our hospital and national definitions of the stillbirth lower boundary from 28 weeks to 24 weeks of gestation. This would allow us to make better comparisons with other developed countries, in line with improvements in healthcare.

Differences between Arterial and Venous Umbilical Cord Plasma Metabolome and Association with Parity

Umbilical cord blood is frequently used in health monitoring of the neonate. Results may be affected by the proportion of arterial and venous cord blood, the venous blood coming from the mother to supply oxygen and nutrients to the infant, and the arterial carrying waste products from the fetus. Here, we sampled arterial and venous umbilical cords separately from 48 newly delivered infants and examined plasma metabolomes using GC-MS/MS metabolomics. We investigated differences in metabolomes between arterial and venous blood and their associations with gestational length, birth weight, sex, and whether the baby was the first born or not, as well as maternal age and BMI. Using multilevel random forest analysis, a classification rate of 79% was achieved for arteriovenous differences (p = 0.004). Several monosaccharides had higher concentrations in the arterial cord plasma while amino acids were higher in venous plasma, suggesting that the main differences in the measured arterial and venous plasma metabolomes are related to amino acid and energy metabolism. Venous cord plasma metabolites related to energy metabolism were positively associated with parity (77% classification rate, p = 0.004) while arterial cord plasma metabolites were not. This underlines the importance of defining cord blood type for metabolomic studies.

Maternal age at birth and neonatal mortality: Associations from 67 low-income and middle-income countries

BACKGROUND

Both young and advanced maternal age have been associated with higher risks of neonatal mortality, but most studies are from high-income countries and the evidence from low- and middle-income countries (LMICs) is scarce.

OBJECTIVE

To investigate the association between maternal age at delivery and neonatal mortality in LMICs.

METHODS

This is a cross-sectional study using data from 159 Demographic and Health Surveys in 67 LMICs between 2000 and 2018. Maternal age at the time of the birth was the exposure variable, and neonatal mortality was the outcome. Multivariable logistic regression model taking into consideration complex survey design was performed with adjustments for maternal education level, paternal education level, rural/urban residence, country, and survey year. Subgroup analyses were performed by time of death, sex, the country's World Bank income classification, the World Health Organization region, and survey year.

RESULTS

A total of 1 395 746 mother-neonate pairs were included. Overall, compared with neonates born to mothers aged 25-29 years, those born to younger mothers aged 20-24, 16-19 and 12-15 years were at an increased risk of mortality (adjusted odds ratio [OR] 1.24, 95% confidence interval [CI] 1.17, 1.30; OR 1.81, 95% CI 1.71, 1.93; OR 2.29, 95% CI 1.96, 2.67, respectively). Neonates born to mothers aged 30-34, 35-39, 40-44, and ≥45 years were also at an increased risk of mortality (OR 1.09, 95% CI 1.03, 1.15; OR 1.30, 95% CI 1.21, 1.39; OR 1.50, 95% CI 1.38, 1.64; OR 1.84, 95% CI 1.54, 2.20, respectively). The results were consistent across most subgroup analyses.

CONCLUSIONS

Neonates born to younger (<25 years) and older mothers (≥30 years) are at increased risk of neonatal death in LMICs.

Placentas From Women of Advanced Maternal Age

CONTEXT.—

The percentage of pregnant women with advanced maternal age (AMA) has increased during the past several decades due to various socioeconomic factors and advances in assisted reproduction. These pregnancies are associated with adverse maternal and fetal outcomes. However, the underlying placental pathology has not been well described.

OBJECTIVE.—

To investigate the placental histopathology associated with AMA pregnancies.

DESIGN.—

Placental pathology from 168 AMA women 35 years or older at delivery was reviewed. The cases were subdivided into 2 age subgroups, ages 35 to 39 and 40 or older, as well as a "pure AMA" subgroup where the only indication for placental examination was AMA. A group of 60 consecutive non-AMA placentas was also identified and used as comparison. The spectrum of histologic features in each case was catalogued.

RESULTS.—

Of the overall AMA cases, meconium deposition was seen in 55% (93 of 168), chorangiosis in 40% (68 of 168), and acute chorioamnionitis in 36% (60 of 168). Fetal vascular malperfusion was also seen with high frequency (30%; 50 of 168). Two histologic alterations found to be significantly different between the 35 to 39 and greater than 40 age subgroups were fetal vascular malperfusion (11% [7 of 65] versus 42% [43 of 103]; P = .001) and delayed villous maturation (1.5% [1 of 65] versus 13% [13 of 103]; P = .02). The pure AMA subgroup showed no statistically significant differences compared with the overall AMA group. Chronic deciduitis was the only statistically significant difference between the overall AMA group and the non-AMA comparison group (14% [23 of 168] versus 30% [18 of 60]; P = .02).

CONCLUSIONS.—

Our findings, particularly the high frequency of fetal vascular malperfusion, suggest that AMA should be an independent indication for placental pathologic examination.

A comparison of neonatal outcomes between adolescent and adult mothers in developed countries: A systematic review and meta-analysis

Evidence suggests that adolescent pregnancies are at increased risk of adverse neonatal outcomes compared to adult pregnancies; however, there are significant inconsistencies in the literature, particularly in studies conducted in developed countries. The objective of this study therefore is to systematically review the current literature with regard to the relationship between adolescent pregnancy and neonatal outcomes. A literature search was conducted in eight electronic databases (AMED, ASSIA, Child Development and Adolescent Studies, CINAHL, Cochrane Library, Health Source: Nursing, Maternity and Infant Care, MEDLINE and Scopus. The reference lists of included studies were also hand searched. Studies were included if: they were conducted in countries with very high human development according to the United Nations Human Development Index; reported at least one comparison between adolescents (19 years or under) and adult mothers (20-34 years); and were published between January 1998 and March 2018. Studies were screened for inclusion and data extracted by one reviewer. A second reviewer independently reviewed a sub-set of studies. Disagreements were resolved by consensus. Meta-analysis was performed using RevMan 5.3 using crude counts reported in the included studies. Sub-group analyses of adolescents aged 17 and under and 18-19 were conducted. Pooled analysis of adjusted odds ratios was also undertaken in order to consider the effect of confounding factors. Meta-analysis effect estimates are reported as risk ratios (RR) and pooled association as adjusted odds ratios (aORs). Point estimates and 95% confidence intervals are presented. After removal of duplicates a total of 1791 articles were identified, of which 20 met the inclusion criteria. The results of the meta-analysis showed adolescents to have increased risk of all primary adverse outcomes investigated. Sub-group analysis suggests an increased risk of perinatal death and low birthweight for children born to adolescent mothers; 17 and under (perinatal death: RR 1.50, CI 1.32-1.71: low birthweight RR 1.43, CI 1.20-1.70); 18-19 (perinatal death RR 1.21, CI 1.06-1.37: low birthweight RR 1.10, CI 1.08-1.57). Mothers aged 17 and under were also at increased risk of preterm delivery (RR 1.64, CI 1.54-1.75). Analysis adjusted for confounders showed increased risk of preterm delivery (aOR 1.23, CI 1.09-1.38), very preterm delivery (aOR 1.22, CI 1.03-1.44) and neonatal death (aOR 1.31, CI 1.14-1.52). Findings show that young maternal age is a significant risk factor for adverse neonatal outcomes in developed countries. Adolescent maternal age therefore should be considered as a potential cause for concern in relation to neonatal health and it is recommended that health care professionals respond accordingly with increased support and monitoring.

Healthcare factors associated with the risk of antepartum and intrapartum stillbirth in migrants in Western Australia (2005-2013): A retrospective cohort study

BACKGROUND

Migrant women, especially from Indian and African ethnicity, have a higher risk of stillbirth than native-born populations in high-income countries. Differential access or timing of ANC and the uptake of other services may play a role. We investigated the pattern of healthcare utilisation among migrant women and its relationship with the risk of stillbirth (SB)-antepartum stillbirth (AnteSB) and intrapartum stillbirth (IntraSB)-in Western Australia (WA).

METHODS AND FINDINGS

A retrospective cohort study using de-identified linked data from perinatal, birth, death, hospital, and birth defects registrations through the WA Data Linkage System was undertaken. All (N = 260,997) non-Indigenous births (2005-2013) were included. Logistic regression analysis was used to estimate odds ratios and 95% CI for AnteSB and IntraSB comparing migrant women from white, Asian, Indian, African, Māori, and 'other' ethnicities with Australian-born women controlling for risk factors and potential healthcare-related covariates. Of all the births, 66.1% were to Australian-born and 33.9% to migrant women. The mean age (years) was 29.5 among the Australian-born and 30.5 among the migrant mothers. For parity, 42.3% of Australian-born women, 58.2% of Indian women, and 29.3% of African women were nulliparous. Only 5.3% of Māori and 9.2% of African migrants had private health insurance in contrast to 43.1% of Australian-born women. Among Australian-born women, 14% had smoked in pregnancy whereas only 0.7% and 1.9% of migrants from Indian and African backgrounds, respectively, had smoked in pregnancy. The odds of AnteSB was elevated in African (odds ratio [OR] 2.22, 95% CI 1.48-2.13, P < 0.001), Indian (OR 1.64, 95% CI 1.13-2.44, P = 0.013), and other women (OR 1.46, 95% CI 1.07-1.97, P = 0.016) whereas IntraSB was higher in African (OR 5.24, 95% CI 3.22-8.54, P < 0.001) and 'other' women (OR 2.18, 95% CI 1.35-3.54, P = 0.002) compared with Australian-born women. When migrants were stratified by timing of first antenatal visit, the odds of AnteSB was exclusively increased in those who commenced ANC later than 14 weeks gestation in women from Indian (OR 2.16, 95% CI 1.18-3.95, P = 0.013), Māori (OR 3.03, 95% CI 1.43-6.45, P = 0.004), and 'other' (OR 2.19, 95% CI 1.34-3.58, P = 0.002) ethnicities. With midwife-only intrapartum care, the odds of IntraSB for viable births in African and 'other' migrants (combined) were more than 3 times that of Australian-born women (OR 3.43, 95% CI 1.28-9.19, P = 0.014); however, with multidisciplinary intrapartum care, the odds were similar to that of Australian-born group (OR 1.34, 95% CI 0.30-5.98, P = 0.695). Compared with Australian-born women, migrant women who utilised interpreter services had a lower risk of SB (OR 0.51, 95% CI 0.27-0.96, P = 0.035); those who did not utilise interpreters had a higher risk of SB (OR 1.20, 95% CI 1.07-1.35, P < 0.001). Covariates partially available in the data set comprised the main limitation of the study.

CONCLUSION

Late commencement of ANC, underutilisation of interpreter services, and midwife-only intrapartum care are associated with increased risk of SB in migrant women. Education to improve early engagement with ANC, better uptake of interpreter services, and the provision of multidisciplinary-team intrapartum care to women specifically from African and 'other' backgrounds may reduce the risk of SB in migrants.

The impact of maternal age on foetal growth patterns and newborn size

The association patterns between maternal age and foetal growth parameters as well as newborn size were analysed using a dataset of 4737 singleton term births taking place at the Viennese Danube hospital. Foetal growth patterns were reconstructed by the results of three ultrasound examinations carried out at the 11th/12th, 20th/21th and 32th/33thweek of gestation. In detail, crown-rump length, biparietal diameter, fronto-occipital diameter, head circumference, abdominal transverse diameter, abdominal anterior-posterior diameter, abdominal circumference, and femur length were determined. Birth weight, birth length and head circumference were measured immediately after birth. Young teenage mothers (≤15 years), older adolescent mothers (16-19 years), mothers of optimal age range (20-35 years) and mothers of advanced age (>35 years) differed significantly in body height, pre-pregnancy weight status and gestational weight gain. Surprisingly, the foetuses of young adolescent mothers were the largest ones during first trimester. During the second and third trimester however, the foetuses of mothers of optimal age range (20-35 years) and mothers older than 35 years showed larger biometric dimensions than adolescent mothers. According to multiple regression analyses, maternal age was significantly related to Foetal head size (ß =-0.04; 95% CI = -0,08 – 0.01; p=0.034) and abdominal dimensions (ß= 0.03; 95% CI = 0.01-0.05; p=0,011) during the second trimester and to birthweight (ß= -0.03; 95% CI= -4.40 – 0.04; p=0.050). The associations however, are quite weak and the statistical significance is maybe due to the large sample size. At the time of birth, offspring of mothers of optimal age range (20 to 35 years) is significantly larger than that of adolescent mothers and mothers of advanced age. Mothers of advanced age showed the significantly highest (p=<0.0001) prevalence (5.6%) of SGA newborns (<2500g). The small size of newborn among young adolescent mothers may be due to a competition over nutrients between the still growing mothers and the foetuses during the third trimester, while placental ageing may be responsible for smaller size of offspring among mothers of advanced age.

[Fetal autopsies : Relic or still a gold standard?]

BACKGROUND

Fetal autopsy rates are decreasing in Western countries although post-mortem examinations render important information for the parents concerning the cause of abortion and risk of recurrence in future pregnancies.

OBJECTIVE

The intention of the presented study was to analyze the development of fetal autopsies in Germany during the last decade and to review accessible information obtained by fetal autopsy.

MATERIAL AND METHODS

Reports of fetal autopsies conducted in two German university Institutes of pathology between 2005 and 2014 were evaluated retrospectively. Demographic data and the correlation between clinical diagnoses and autopsy findings were assessed. In addition, differences between spontaneous and induced cases of abortion and differences between the institutes were also documented.

RESULTS

Overall, 428 fetal autopsies were performed, whereby the number of autopsies decreased by 24.2% during the study period. Of the examined fetuses 29.7% were induced abortions which as expected exhibited different malformations compared to cases of spontaneous abortion (p < 0.001). There was no evidence of a malformation or other cause of death in 27.1% of the cases and 95.7% of these abortions occurred spontaneously. A discrepancy between clinical and autopsy findings was evident in 6.8% of cases and 3.5% of the autopsy examinations revealed at least one additional malformation compared to the prenatal clinical data.

CONCLUSION

Despite improvements in prenatal diagnostics, fetal autopsies remain an important diagnostic tool even today contributing additional information in a considerable number of cases potentially revising clinical diagnoses.

Risk Assessment of Adverse Birth Outcomes in Relation to Maternal Age

BACKGROUND

Although a number of studies have investigated correlations of maternal age with birth outcomes, an extensive assessment using age as a continuous variable is lacking. In the current study, we estimated age-specific risks of adverse birth outcomes in childbearing women.

METHOD

National population-based data containing maternal and neonatal information were derived from the Health Promotion Administration, Taiwan. A composite adverse birth outcome was defined as at least anyone of stillbirth, preterm birth, low birth weight, macrosomia, neonatal death, congenital anomaly, and small for gestational age (SGA). Singletons were further analyzed for outcomes of live birth in relation to each year of maternal age. A log-binomial model was used to adjust for possible confounders of maternal and neonatal factors.

RESULTS

In total, 2,123,751 births between 2001 and 2010 were utilized in the analysis. The risk of a composite adverse birth outcome was significantly higher at extreme maternal ages. In specific, risks of stillbirth, neonatal death, preterm birth, congenital anomaly, and low birth weight were higher at the extremes of maternal age. Furthermore, risk of macrosomia rose proportionally with an increasing maternal age. In contrast, risk of SGA declined proportionally with an increasing maternal age. The log-binomial model showed greater risks at the maternal ages of <26 and > 30 years for a composite adverse birth outcome.

CONCLUSIONS

Infants born to teenagers and women at advanced age possess greater risks for stillbirth, preterm birth, neonatal death, congenital anomaly, and low birth weight. Pregnancies at advanced age carry an additional risk for macrosomia, while teenage pregnancies carry an additional risk for SGA. The data suggest that the optimal maternal ages to minimize adverse birth outcomes are 26∼30 years.

Pregnancy outcomes in very advanced maternal age pregnancies: the impact of assisted reproductive technology

OBJECTIVE

To determine whether there are differences in adverse pregnancy outcomes in very advanced maternal age (vAMA) women who conceived with assisted reproductive technologies (ART) compared with spontaneous conceptions.

DESIGN

Retrospective cohort study.

SETTING

Academic tertiary care medical center.

PATIENT(S)

A total of 472 women aged ≥45 years who delivered at one institution.

INTERVENTION(S)

Mode of conception.

MAIN OUTCOME MEASURE(S)

Maternal and neonatal outcomes.

RESULT(S)

For singleton pregnancies, vAMA women who conceived with ART were significantly older (47.0 ± 2.3 vs. 45.6 ± 0.1 years), more likely to be white (88.1% vs. 75.6%), and less parous (0.4 ± 0.9 vs. 1.2 ± 1.8) than vAMA women who conceived spontaneously. They were at significantly increased risk for cesarean delivery (CD) (75.1% vs. 49.7%) and were more likely to undergo elective primary CD without labor (25.4% vs. 9.4%). Risk of retained placenta was also significantly higher (2.7% vs. 0%). Rates of other maternal complications and neonatal outcomes were similar. Subgroup analysis of ART singleton pregnancies did not demonstrate differences in women using autologous oocytes versus donor oocytes.

CONCLUSION(S)

Very advanced maternal age women who conceive after ART are more likely to be white, older, primiparous, and are more likely to proceed with an elective CD compared with vAMA women who conceive spontaneously. The increased risk of retained placenta in women who conceive with ART may indicate an underlying risk for placentation defects.

Molecular and cytogenetic analysis in stillbirth: results from 481 consecutive cases

INTRODUCTION

The underlying causes of stillbirth are heterogeneous and in many cases unexplained. Our aim was to conclude clinical results from karyotype and quantitative fluorescence-polymerase chain reaction (QF-PCR) analysis of all stillbirths occurring in Stockholm County between 2008 and 2012. By screening a subset of cases, we aimed to study the possible benefits of chromosomal microarray (CMA) in the analysis of the etiology of stillbirth.

METHODS

During 2008-2012, 481 stillbirths in Stockholm County were investigated according to a clinical protocol including karyotype or QF-PCR analysis. CMA screening was performed on a subset of 90 cases, corresponding to all stillbirths from 2010 without a genetic diagnosis.

RESULTS

Chromosomal aberrations were detected by karyotype or QF-PCR analysis in 7.5% of the stillbirths. CMA analysis additionally identified two known syndromes, one aberration disrupting a known disease gene, and 26 variants of unknown significance. Furthermore, CMA had a significantly higher success rate than karyotyping (100 vs. 80%, p < 0.001).

DISCUSSION

In the analysis of stillbirth, conventional karyotyping is prone to failure, and QF-PCR is a useful complement. We show that CMA has a higher success rate and aberration detection frequency than these methods, and conclude that CMA is a valuable tool for identification of chromosomal aberrations in stillbirth.

Advanced maternal age and adverse pregnancy outcome: evidence from a large contemporary cohort

BACKGROUND

Recent decades have witnessed an increase in mean maternal age at childbirth in most high-resourced countries. Advanced maternal age has been associated with several adverse maternal and perinatal outcomes. Although there are many studies on this topic, data from large contemporary population-based cohorts that controls for demographic variables known to influence perinatal outcomes is limited.

METHODS

We performed a population-based cohort study using data on all singleton births in 2004-2008 from the North Western Perinatal Survey based at The University of Manchester, UK. We compared pregnancy outcomes in women aged 30-34, 35-39 and ≥40 years with women aged 20-29 years using log-linear binomial regression. Models were adjusted for parity, ethnicity, social deprivation score and body mass index.

RESULTS

The final study cohort consisted of 215,344 births; 122,307 mothers (54.19%) were aged 20-29 years, 62,371(27.63%) were aged 30-34 years, 33,966(15.05%) were aged 35-39 years and 7,066(3.13%) were aged ≥40 years. Women aged 40+ at delivery were at increased risk of stillbirth (RR = 1.83, [95% CI 1.37-2.43]), pre-term (RR = 1.25, [95% CI: 1.14-1.36]) and very pre-term birth (RR = 1.29, [95% CI:1.08-1.55]), Macrosomia (RR = 1.31, [95% CI: 1.12-1.54]), extremely large for gestational age (RR = 1.40, [95% CI: 1.25-1.58]) and Caesarean delivery (RR = 1.83, [95% CI: 1.77-1.90]).

CONCLUSIONS

Advanced maternal age is associated with a range of adverse pregnancy outcomes. These risks are independent of parity and remain after adjusting for the ameliorating effects of higher socioeconomic status. The data from this large contemporary cohort will be of interest to healthcare providers and women and will facilitate evidence based counselling of older expectant mothers.

Heavy prenatal alcohol exposure and increased risk of stillbirth

OBJECTIVE

To investigate the association between heavy prenatal alcohol exposure and stillbirth.

DESIGN

Data linkage cohort study.

SETTING

Western Australia (WA).

POPULATION

The exposed cohort included mothers with an alcohol-related diagnosis (International Classification of Diseases, ninth/tenth revisions) recorded in health data sets and all their offspring born in WA (1983-2007). Mothers without an alcohol-related diagnosis and their offspring comprised the comparison cohort.

METHODS

Exposed and comparison mothers were identified through the WA Data Linkage System. Odds ratios for stillbirth at 20+ weeks of gestation were estimated by logistic regression, stratified by Aboriginal status.

MAIN OUTCOME MEASURES

The proportion of stillbirths at 20+ weeks of gestation is presented per 1000 births, as well as adjusted odds ratios (aOR) and 95% confidence intervals (95% CI), and population-attributable fractions.

RESULTS

Increased odds of stillbirth were observed for mothers with an alcohol-related diagnosis at any stage of their life for both non-Aboriginal (aOR 1.36; 95% CI 1.05-1.76) and Aboriginal (aOR 1.33; 95% CI 1.08-1.64) births. When an alcohol diagnosis was recorded during pregnancy, increased odds were observed for non-Aboriginal births (aOR 2.24; 95% CI 1.09-4.60), with the highest odds of Aboriginal stillbirth occurring when an alcohol diagnosis was recorded within 1 year postpregnancy (aOR 2.88; 95% CI 1.75-4.73). The population-attributable fractions indicate that 0.8% of non-Aboriginal and 7.9% of Aboriginal stillbirths are the result of heavy alcohol consumption.

CONCLUSIONS

Prevention of heavy maternal alcohol use has the potential to reduce stillbirths. The lack of an association between exposure during pregnancy and Aboriginal stillbirth in this study needs further investigation.

Advanced maternal age and obstetric morbidity for women giving birth in Victoria, Australia: A population-based study

BACKGROUND

As the proportions of older women giving birth increase, there is a growing body of evidence on the increased risks of poorer maternal and perinatal outcomes for this group. However, the associations are not completely understood. This study aimed to establish the prevalence of selected maternal morbidities and examine whether advanced maternal age is associated with a higher risk of morbidity for women giving birth in Victoria.

METHOD

Data on all births over 20 weeks‧ gestation for 2005 and 2006 were obtained from the Victorian Perinatal Data Collection. Unadjusted and adjusted analyses were undertaken using logistic regression to examine and quantify the association between advanced maternal age (35 years and older) and selected obstetric morbidities and complications.

RESULTS

There was evidence of an association between older maternal age and selected morbidities and complications. Older nulliparous women were at highest odds of gestational diabetes (AdjOR, 1.83; 95% CI, 1.67-2.02), placenta praevia (AdjOR, 2.02; 95% CI, 1.68-2.44), multiple birth (AdjOR, 1.80; 95% CI, 1.58-2.06) and caesarean delivery (AdjOR, 1.93; 95% CI, 1.84-2.02). Older multiparous women were at highest odds of gestational diabetes (AdjOR, 2.01; 95% CI, 1.88-2.15) and placenta praevia (AdjOR, 2.11; 95% CI, 1.83-2.44).

CONCLUSIONS

Older women giving birth in Victoria are at an increased risk of a range of obstetric morbidities. Delayed childbearing for an increasing number of women has societal and public health ramifications and will potentially place greater demand on healthcare services.

Racial and ethnic disparities in United States: stillbirth rates: trends, risk factors, and research needs

As with most adverse health outcomes, there has been long standing and persistent racial and ethnic disparity for stillbirth in the United States. In 2005, the stillbirth rate (fetal deaths ≥ 20 weeks' gestation per 1000 fetal deaths and live births) for non-Hispanic blacks was 11.13 compared with 4.79 for non-Hispanic whites. Rates were intermediate for American Indian or Alaska Natives (6.17) and Hispanics (5.44). There is racial disparity for both early (< 28 weeks' gestation) and late stillbirths. We review available data regarding risk factors for stillbirth with a focus on those factors that are more prevalent in certain racial/ethnic groups and those factors that appear to have a more profound effect in certain racial/ethnic groups. Although many factors, including genetics, environment, stress, social issues, access to and quality of medical care and behavior, contribute to racial disparity in stillbirth, the reasons for the disparity remain unclear. Knowledge gaps and recommendations for further research and interventions intended to reduce racial disparity in stillbirth are highlighted.

Advanced maternal age, short interpregnancy interval, and perinatal outcome

OBJECTIVE

The purpose of this study was to evaluate whether the association between short interpregnancy intervals and perinatal outcome varies with maternal age.

STUDY DESIGN

We performed a retrospective cohort study among 263,142 Dutch women with second deliveries that occurred between 2000 and 2007. Outcome variables were preterm delivery (<37 weeks of gestation), low birthweight in term deliveries (<2500 g) and small-for-gestational age (<10th percentile for gestational age on the basis of sex- and parity-specific Dutch standards).

RESULTS

Short interpregnancy intervals (<6 months) was associated positively with preterm delivery and low birthweight, but not with being small for gestational age. The association of short interpregnancy interval with the risk of preterm delivery was weaker among older than younger women. There was no clear interaction between short interpregnancy interval and maternal age in relation to low birthweight or small for gestational age.

CONCLUSION

The results of this study indicate that the association of short interpregnancy interval with preterm delivery attenuates with increasing maternal age.

Major risk factors for stillbirth in high-income countries: a systematic review and meta-analysis

BACKGROUND

Stillbirth rates in high-income countries have shown little or no improvement over the past two decades. Prevention strategies that target risk factors could be important in rate reduction. This systematic review and meta-analysis was done to identify priority areas for stillbirth prevention relevant to those countries.

METHODS

Population-based studies addressing risk factors for stillbirth were identified through database searches. The factors most frequently reported were identified and selected according to whether they could potentially be reduced through lifestyle or medical intervention. The numbers attributable to modifiable risk factors were calculated from data relating to the five high-income countries with the highest numbers of stillbirths and where all the data required for analysis were available. Odds ratios were calculated for selected risk factors, from which population-attributable risk (PAR) values were calculated.

FINDINGS

Of 6963 studies initially identified, 96 population-based studies were included. Maternal overweight and obesity (body-mass index >25 kg/m(2)) was the highest ranking modifiable risk factor, with PARs of 8-18% across the five countries and contributing to around 8000 stillbirths (≥22 weeks' gestation) annually across all high-income countries. Advanced maternal age (>35 years) and maternal smoking yielded PARs of 7-11% and 4-7%, respectively, and each year contribute to more than 4200 and 2800 stillbirths, respectively, across all high-income countries. In disadvantaged populations maternal smoking could contribute to 20% of stillbirths. Primiparity contributes to around 15% of stillbirths. Of the pregnancy disorders, small size for gestational age and abruption are the highest PARs (23% and 15%, respectively), which highlights the notable role of placental pathology in stillbirth. Pre-existing diabetes and hypertension remain important contributors to stillbirth in such countries.

INTERPRETATION

The raising of awareness and implementation of effective interventions for modifiable risk factors, such as overweight, obesity, maternal age, and smoking, are priorities for stillbirth prevention in high-income countries.

FUNDING

The Stillbirth Foundation Australia, the Department of Health and Ageing, Canberra, Australia, and the Mater Foundation, Brisbane, Australia.

Impact of change in maternal age composition on the incidence of Caesarean section and low birth weight: analysis of delivery records at a tertiary hospital in Tanzania, 1999-2005

BACKGROUND

Previous studies on change in maternal age composition in Tanzania do not indicate its impact on adverse pregnancy outcomes. We sought to establish temporal changes in maternal age composition and their impact on annual Caesarean section (CS) and low birth weight deliveries (LBWT) at Muhimbili National Hospital in Tanzania.

METHODS

We conducted data analysis of 91,699 singleton deliveries that took place in the hospital between 1999 and 2005. The data were extracted from the obstetric data base. Annual proportions of individual age groups were calculated and their trends over the years studied. Multiple logistic analyses were conducted to ascertain trends in the risks of CS and LBWT. The impact of age composition changes on CS and LBWT was estimated by calculating annual numbers of these outcomes with and without the major changes in age composition, all others remaining equal. In all statistics, a p value < 0.05 was considered significant.

RESULTS

The proportion of teenage mothers (12-19 years) progressively decreased over time while that of 30-34 years age group increased. From 1999, the risk of Caesarean delivery increased steadily to a maximum in 2005 [adjusted OR = 1.7; 95%CI (1.6-1.8)] whereas that of LBWT declined to a minimum in 2005 (adjusted OR = 0.76; 95% CI (0.71-0.82). The current major changes in age trend were responsible for shifts in the number of CS of up to206 cases per year. Likewise, the shift in LBWT was up to 158 cases per year, but the 30-34 years age group had no impact on this.

CONCLUSION

The population of mothers giving birth at MNH is progressively becoming older with substantial impact on the incidence of CS and LBWT. Further research is needed to estimate the health cost implications of this change.

Temporal changes in key maternal and fetal factors affecting birth outcomes: a 32-year population-based study in an industrial city

Background

The link between maternal factors and birth outcomes is well established. Substantial changes in society and medical care over time have influenced women's reproductive choices and health, subsequently affecting birth outcomes. The objective of this study was to describe temporal changes in key maternal and fetal factors affecting birth outcomes in Newcastle upon Tyne over three decades, 1961–1992.

Methods

For these descriptive analyses we used data from a population-based birth record database constructed for the historical cohort Particulate Matter and Perinatal Events Research (PAMPER) study. The PAMPER database was created using details from paper-based hospital delivery and neonatal records for all births during 1961–1992 to mothers resident in Newcastle (out of a total of 109,086 singleton births, 97,809 hospital births with relevant information). In addition to hospital records, we used other sources for data collection on births not included in the delivery and neonatal records, for death and stillbirth registrations and for validation.

Results

The average family size decreased mainly due to a decline in the proportion of families with 3 or more children. The distribution of mean maternal ages in all and in primiparous women was lowest in the mid 1970s, corresponding to a peak in the proportion of teenage mothers. The proportion of older mothers declined until the late 1970s (from 16.5% to 3.4%) followed by a steady increase. Mean birthweight in all and term babies gradually increased from the mid 1970s. The increase in the percentage of preterm birth paralleled a two-fold increase in the percentage of caesarean section among preterm births during the last two decades. The gap between the most affluent and the most deprived groups of the population widened over the three decades.

Conclusion

Key maternal and fetal factors affecting birth outcomes, such as maternal age, parity, socioeconomic status, birthweight and gestational age, changed substantially during the 32-year period, from 1961 to 1992. The availability of accurate gestational age is extremely important for correct interpretation of trends in birthweight.