The risk of intrapartum stillbirth among smokers of advanced maternal age

BACKGROUND/AIM: The effects of advanced maternal age and smoking in pregnancy on fetal survival have previously been reported. However, whether advanced maternal age modifies the relationship between smoking in pregnancy and intrapartum stillbirth remains unknown. We therefore set out to determine the impact of advanced maternal age (> or =35 years) on the association between smoking during pregnancy and intrapartum stillbirth by employing retrospective analysis of birth registry data. METHODS: We used a cohort of singleton births in Missouri from 1978 through 1997 (N = 1,436,628) to compute the risk of total, antepartum, and intrapartum stillbirth in smoking mothers. We categorized mothers into two age groups: "younger" (<35 years), and "older" (> or =35 years). Non-smoking mothers age <35 years were the referent category. Cox regression models were used to generate independent measures of association between intrauterine tobacco exposure and the risk of total, antepartum, and intrapartum stillbirth in each age group. RESULTS: A total of 5,772 counts of stillbirth were identified, yielding a stillbirth rate of 4.0 per 1,000. Approximately 33% (N = 1,900) occurred among older smokers resulting in a stillbirth rate of 9.1 per 1,000. The probability of intrapartum stillbirth was greatest among older smokers, followed by younger smokers and lowest among younger non-smokers (P < 0.01). As compared to non-smoking younger gravidas, younger smoking mothers had a 30% greater likelihood for both antepartum and intrapartum stillbirth (adjusted hazard ratio [95% confidence interval]: 1.3 [1.2-1.4] and 1.3 [1.2-1.5], respectively). Among older smokers the risk for intrapartum stillbirth was three times that of the referent group (adjusted hazard ratio: 3.2, 95% confidence interval: 2.2-4.5). CONCLUSIONS: The risk of intrapartum stillbirth associated with smoking in pregnancy is potentiated by the age of the mother. This information will help policy makers develop targeted smoking cessation campaigns and positively impact quit rates in older mothers.     

Young maternal age and risk of intrapartum stillbirth

OBJECTIVES: To determine the risk of intrapartum stillbirth among teen mothers. METHODS: The Missouri maternally linked data containing births from 1978 to 1997 were analyzed. The study group (teen mothers) was sub-divided into younger (<15 years) and older (15-19 years) teenagers. Women aged 20-24 were the referent category. We used Kaplan-Meier product-limit estimator to calculate the cumulative probability of death for each group and the Cox Proportional Hazards Regression models to obtain adjusted hazards ratios. RESULTS: The rate of antepartum and intrapartum stillbirth among teenagers was 3.8 per 1,000 and 1.0 per 1,000, respectively, compared to 3.5 per 1,000 and 0.8 per 1,000 among the reference group. The adjusted risk of intrapartum stillbirth was more than 4 times as high among younger teens (adjusted hazard ratio [AHR] 4.3 [95% CI 4.0-4.7]) and 50% higher among older teens (AHR 1.5 [95% CI 1.2-1.8]). The risk of intrapartum stillbirth occurred in a dose-dependent fashion, with risk increasing as maternal age decreased (P < 0.01). CONCLUSION: Teenagers are at an increased risk of stillbirth, with the greatest risk disparity occurring intrapartum, especially among younger teens. This new information is potentially useful for targeting intervention measures aimed at improving in utero fetal survival among pregnant women at the lower extreme of the maternal age spectrum.     

Risk factors for antepartum and intrapartum stillbirth: a population-based study

To examine disparities in risk factors for stillbirths and its occurrence in the antepartum versus intrapartum periods. A population-based, cross-sectional study using data on women that delivered singleton births between 20 and 43 weeks in Missouri (1989-1997) was conducted (n = 626,883). Hazard ratios and 95% confidence intervals were derived from regression models and population attributable fractions were estimated to examine the impact of risk factors on stillbirth. Among African Americans, risks of antepartum and intrapartum stillbirth were 5.6 and 1.1 per 1,000 singleton births, respectively; risks among whites were 3.4 and 0.5 per 1,000 births, respectively. Maternal age > or = 35 years, lack of prenatal care, prepregnancy body mass index (BMI) > or = 30 kg/m2, and prior preterm or small-for-gestational age birth were significantly associated with increased risk for antepartum stillbirth among whites, but not African Americans. BMI < or = 18.5 kg/m2 was associated with antepartum and intrapartum stillbirth among African Americans, but not whites. The presence of any congenital anomaly, abruption, and cord complications were associated with antepartum stillbirth in both races. Premature rupture of membranes was associated with intrapartum stillbirth among whites and African Americans, but intrapartum fever was associated with intrapartum stillbirth among African Americans. These risk factors were implicated in 54.9% and 19.7% of antepartum and intrapartum stillbirths, respectively, among African American women, and in a respective 46.6% and 11.9% among white women. Considerable heterogeneity in risk factors between antepartum and intrapartum stillbirths is evident. Knowledge on timing of stillbirth specific risk factors may help clinicians in decreasing antepartum and intrapartum stillbirth risks through monitoring and timely intervention.     

Community-based stillbirth rates and risk factors in rural Sarlahi, Nepal

Objective

To assess stillbirth rates and antepartum risk factors in rural Nepal.

Methods

Data were collected prospectively during a cluster-randomized, community-based trial in Sarlahi, Nepal, from 2002 to 2006. Multivariate regression modeling was performed to calculate adjusted relative risk estimates.

Results

Among 24 531 births, the stillbirth rate was 35.4 per 1000 births (term stillbirth rate 21.2 per 1000 births). Most births occurred at home without a skilled birth attendant. The majority (69%) of intrapartum maternal deaths resulted in stillbirth. The adjusted RR (aRR) of stillbirth was 2.74 among nulliparas and 1.47 among mothers with history of a child death. Mothers above the age of 30 years carried a 1.59-fold higher risk for stillbirth than mothers who were 20-24 years old. The stillbirth risk was lower among households where the father had any formal education (aRR 0.70). Land ownership (aRR 0.85) and Pahadi ethnicity (aRR 0.67; reference: Madhesi ethnicity) were associated with significantly lower risks of stillbirth.

Conclusion

Stillbirth rates were high in rural Nepal, with the majority of stillbirths occurring at full-term gestation. Nulliparity, history of prior child loss, maternal age above 30 years, Madhesi ethnicity, and socioeconomic disadvantage were significant risk factors for stillbirth.Clinicaltrials.govNCT00 109616     

Prenatal Smoking among Adolescents and Risk of Fetal Demise before and during Labor

Study ObjectiveTo investigate the relationship between smoking during pregnancy and the occurrence of stillbirth phenotypes among adolescent mothers.DesignRetrospective cohortSettingSingleton births in Missouri from 1978 through 1997.ParticipantsTwo groups of “younger” (<15 years) and “older” (15–19 years) adolescent mothers were compared to “mature” mothers (age 20–24 years).Main Outcome MeasuresCox Proportional Hazards Regression models generated adjusted risk estimates of the association between intrauterine nicotine exposure and the risk of total, antepartum, and intrapartum stillbirth in each age group.ResultsApproximately 32% (N = 205,887) of the total 633,849 singleton births analyzed were among adolescent mothers. The overall prevalence of smoking was 31.2%, with the lowest prevalence (14.1%) among the youngest mothers while older adolescents had the highest (31.7%). The risk for intrapartum stillbirth among smoking adolescents <15 years of age was twice the risk for older adolescent and mature mothers. The risk of intrapartum stillbirth among smokers decreased as maternal age increased: [adjusted hazard ratio (AHR), 95% confidence interval (CI) for young mothers: 4.0, 95%CI = 0.6–28.7; for older adolescents AHR = 1.5, 95%CI = 1.1–2.1 and for mature mothers AHR = 1.8, 95% CI = 1.4–2.2], respectively.ConclusionsIn utero tobacco exposure has maternal age-related differential and lethal effects on the fetus. Young maternal age tends to potentiate these effects. There is a public health need to develop appropriate smoking cessation messages targeted specifically to this high risk group.     

Maternal weight, pregnancy weight gain, and the risk of antepartum stillbirth

OBJECTIVE: This study investigated whether the risk of antepartum stillbirth increases with body mass index during early pregnancy and also investigated the association between weight gain during pregnancy and the risk of antepartum stillbirth.Study Design: This population-based case-control study included 649 women with antepartum stillbirths and 690 control subjects among Swedish nulliparous women. RESULTS: Compared with lean mothers (body mass index < or = 19.9 kg/m2), the odds ratios for risk of antepartum deaths were as follows: normal weight (body mass index, 20.0-24.9 kg/m2) odds ratio, 1.2 (95% confidence interval, 0.8-1.7); overweight (body mass index 25.0-29.9 kg/m2), odds ratio, 1.9 (95% confidence interval, 1.2-2.9); and obese (body mass index > or = 30.0 kg/m2) odds ratio, 2.1 (95% confidence interval, 1.2-3.6). For term antepartum death corresponding risks were even higher, with odds ratios of 1.6 (95% confidence interval, 0.9-2.6) for normal weight, 2.7 (95% confidence interval, 1.5-5.0) for overweight, and 2.8 (95% confidence interval, 1.3-6.0) for obese women, respectively. Maternal weight gain during pregnancy was not associated with risk of antepartum stillbirth. CONCLUSION: Maternal overweight condition increased the risk of antepartum stillbirth, especially term antepartum stillbirth, whereas weight gain during pregnancy was not associated with risk.     

A case-control study of stillbirths in northeast Brazil.

An institution based case-control study to determine risk factors for stillbirths was conducted in the city of Natal, NE Brazil, where 90% of deliveries take place in health facilities. Two hundred thirty-four singleton stillborn cases were compared to 2555 liveborn singleton control infants of normal birth-weight and gestational age. Information was obtained by postnatal interview and anthropometry, and review of medical records. Univariate analyses revealed a large number of potential risk factors, but after adjustment by logistic regression only six factors remained significantly associated with stillbirth. These were low maternal weight, less than or equal to 50 kg and a history of pregnancy loss, both with odds ratios (OR) of 1.8, inadequate prenatal care defined as less than five visits (OR = 1.9), gestational complications (OR = 14.2), intrapartum complications (OR = 2.0), and congenital malformations (OR = 8.7). There was also an increased risk of stillbirth among older mothers who smoked (OR = 1.4), and evidence of an interaction between smoking and complications of pregnancy. From the public health perspective, the most important factors amenable to intervention were inadequate prenatal care and antenatal or intrapartum complications which were associated with substantial attributable risks (23.8%, 35.2%, and 10.2%, respectively). Thus, in this population, future reductions of the high stillbirth rate (27.2 per 1000 births) will largely depend on the coverage, utilization, and quality of antenatal and intrapartum care.     

Extreme obesity and risk of stillbirth among black and white gravidas

OBJECTIVE: To estimate the risk for stillbirth among three generally accepted obesity subtypes based on severity. METHODS: We used the Missouri maternally linked cohort data containing births from 1978 to 1997. Using prepregnancy weight and height, mothers were classified on the basis of calculated body mass index (BMI) above 30 into three subsets: class I (30-34.9), class II (35-39.9), and extreme obesity (greater than or equal to 40). Using normal-weight, white women (18.5-24.9) as a reference, we applied Cox proportional hazard regression models to estimate risks for stillbirth. RESULTS: The prevalence of obesity in pregnant women was 9.5% (12.8% among blacks and 8.9% among whites). Overall, obese mothers were about 40% more likely to experience stillbirth compared with nonobese gravidas (adjusted hazard ratio 1.4; 95% confidence interval [CI] 1.3-1.5). The risk for stillbirth increased in a dose-dependent fashion with increase in BMI: class I (adjusted hazard ratio 1.3; 95% CI 1.2-1.4); class II (adjusted hazard ratio 1.4; 95% CI 1.3-1.6) and extreme obesity (adjusted hazard ratio 1.9; 95% CI 1.6-2.1; P for trend <.01). Obese black mothers experienced more stillbirths than their white counterparts (adjusted hazard ratio 1.9; 95% CI 1.7-2.1 compared with adjusted hazard ratio 1.4; 95% CI 1.3-1.5). The black disadvantage in stillbirth widened with increase in BMI, with the greatest difference observed among extremely obese black mothers (adjusted hazard ratio 2.3; 95% CI 1.8-2.9). CONCLUSION: Obesity is a risk factor for stillbirth, particularly among extremely obese, black mothers. Strategies to reduce black-white disparities in birth outcomes should consider targeting obese, black women. LEVEL OF EVIDENCE: II.     

Epidemiology of fetal death in Latin America

BACKGROUND: To identify risk factors associated with fetal death, and to measure the rate and the risk of fetal death in a large cohort of Latin American women. METHODS: We analyzed 837,232 singleton births recorded in the Perinatal Information System Database of the Latin American Center for Perinatology and Human Development (CLAP) between 1985 and 1997. The risk factors analyzed included fetal factors and maternal sociodemographic, obstetric, and clinical characteristics. Adjusted relative risks were obtained, after adjustment for potential confounding factors, through multiple logistic regression models based on the method of generalized estimating equations. RESULTS: There were 14,713 fetal deaths (rate=17.6 per 1000 births). The fetal death risk increased exponentially as pregnancy advanced. Thirty-seven percent of all fetal deaths occurred at term, and 64% were antepartum. The main risk factors associated with fetal death were lack of antenatal care (adjusted relative risk [aRR]=4.26; 95% confidence interval, 3.84-4.71) and small for gestational age (aRR=3.26; 95% CI, 3.13-3.40). In addition, the risk of death during the intrapartum period was almost tenfold higher for fetuses in noncephalic presentations. Other risk factors associated with stillbirth were: third trimester bleeding, eclampsia, chronic hypertension, preeclampsia, syphilis, gestational diabetes mellitus, Rh isoimmunization, interpregnancy interval<6 months, parity > or =4, maternal age > or =35 years, illiteracy, premature rupture of membranes, body mass index > or =29.0, maternal anemia, previous abortion, and previous adverse perinatal outcomes. CONCLUSIONS: There are several preventable factors that should be dealt with in order to reduce the gap in fetal mortality between Latin America and developed countries.     

Is advanced maternal age an independent risk factor for uteroplacental insufficiency?

OBJECTIVE: To determine whether maternal age 35 years or older is an independent risk factor for uteroplacental insufficiency and thus an independent indication for antepartum testing. STUDY DESIGN: A retrospective cohort analysis was performed of all deliveries at Los Angeles County-University of Southern California Women's and Children's Hospital between August 1, 1995, and September 1, 2003. Women with documented indications for antepartum testing, fetal anomalies, or delivery prior to 34 weeks were excluded from analysis. Markers of uteroplacental insufficiency included stillbirth, birth weight less than the 10th percentile, fetal distress, cesarean section for fetal distress, oligohydramnios, meconium passage, and 5-minute Apgar score less than 7. RESULTS: Indications for antepartum testing were significantly more common in women 35 years or older (33.2% versus 27.0%). After excluding women with indications for antepartum testing, anomalous fetuses, and women delivering prior to 34 weeks, stillbirth was twice as common in women 35 years and older. However, among stillbirths, growth restriction occurred with similar frequency in the older (28.6%) and younger (25.0%) cohorts. Among live births, 2 markers of uteroplacental insufficiency, intrapartum fetal distress (5.7% versus 4.1%) and cesarean delivery for fetal distress (4.0% versus 2.4%) were significantly more common in the older cohort. All other markers of uteroplacental insufficiency were observed with similar frequency in the 2 groups. CONCLUSIONS: After excluding women with other indications for antepartum testing, fetal anomalies, and delivery prior to 34 weeks, stillbirth was twice as common in women 35 years of age or older as in those younger than 35 years. The increased rate of stillbirth does not appear to be explained by a higher rate of uteroplacental insufficiency.     

Management of pregnancy complications in women of advanced maternal age

The average age of women at childbirth in high resource obstetric settings has been increasing steadily for approximately 30 years. Women aged 35 years or over have an increased risk of gestational hypertensive disease, gestational diabetes, placenta praevia, placental abruption, perinatal death, preterm labour, fetal macrosomia and fetal growth restriction. Unsurprisingly, rates of obstetric intervention are higher among older women. Of particular concern is the increased risk of antepartum stillbirth at term in women of advanced maternal age. In all maternal age groups, the risk of stillbirth is higher among nulliparous women than among multiparous women. Women of advanced maternal age (>40 years) should be given low dose aspirin in the presence of an additional risk factor for pre-eclampsia and offered serial ultrasounds for fetal growth and wellbeing. Given the increased risk of antepartum stillbirth, induction of labour from 39 weeks’ gestation should be discussed with woman.     

Advanced maternal age

The average age of women at childbirth in industrialised nations has been increasing steadily for approximately 30 years. Women aged 35 years or over have an increased risk of gestational hypertensive disease, gestational diabetes, placenta praevia, placental abruption, perinatal death, preterm labour, fetal macrosomia and fetal growth restriction. Unsurprisingly, rates of obstetric intervention are higher among older women. Of particular concern is the increased risk of antepartum stillbirth at term in women of advanced maternal age. In all maternal age groups, the risk of stillbirth is higher among nulliparous women than among multiparous women. Women of advanced maternal age (>40 years) should be given low dose aspirin (in the presence of an additional risk factor for pre-eclampsia) and offered serial ultrasounds for fetal growth and wellbeing; given the increased risk of antepartum stillbirth, induction of labour from 39 weeks’ gestation should be discussed with the woman.     

Pregnancy after 34 years: risks and evolution of risks

A study of the risks of late pregnancy for mothers and their children indicates that there is still excess risk for mothers over age 35 but the difference is decreasing relative to the general population. National surveys of pregnancy and delivery conducted in France in 1976 and 1981 were the major source of data, supplemented by records of women giving birth in the Clinic Baudelocque, a university clinic in Paris, and by foreign data. Maternal mortality in France among women 35 and over declined from 71.7/100,000 in 1975 to 39.6/100,000 in 1983, at the same time that maternal mortality in the general population declined from 19.9 to 15.5/100,000. The risk of mortality for mothers over 34 was 3.6 times higher in 1975 and 2.6 times higher in 1983 than for the general population. In a series of 3858 pregnancies overall and 544 among women over 34, the rates of hypertension were 9.2% for all mothers and 12.3% for older mothers, while the rate for diabetes was 1.1% for all mothers and 2.4% for older mothers. Rates of proteinuria and urinary infection were about the same for the 2 groups. Rates of stillbirth in 1983 were 13.0/1000 for children of mothers 35 and over 7.6/1000 for the population at large. The frequency of trisomy 21 is very closely related to age, but the excess risk due to age is declining as result of more frequent antenatal diagnosis among older mothers. By 1976, the risk of prematurity of low birth weight was almost the same for infants of older mothers as for the population at large. Rates of prematurity were 5.6% for the general population and 5.9% for older mothers, while rates of birth weight under 2500 g were 5.2% for the general population and 5.6% for older mothers. The number of prenatal visits increased more for mothers over 34 years old than for the general population between 1976-81; in 1981, 46.4% of older mothers but only 32.3% of the general population had more than 7 prenatal consultations. The proportion of older mothers in the labor force and with university education increased considerably between 1976-81. 2 factors appear to have played a role in the improved health of older mothers and their children, improved prenatal surveillance and changes in the characteristics of the older mothers themselves. Data for England indicate that risk of prenatal mortality varies as a function of the father's occupation. The excess risk for infants of older mothers in England tends to disappear for children of the highest social classes.     

The risk of unexplained antepartum stillbirth in second pregnancies following caesarean section in the first pregnancy

Objective  To determine if a previous caesarean section increases the risk of unexplained antepartum stillbirth in second pregnancies.
Study design  Retrospective cohort study.
Setting  Large Canadian perinatal database.
Population  158 502 second births.
Methods  Data were obtained from a large perinatal database, which supplied data on demographics, pregnancy complications, maternal medical conditions, previous caesarean section and pregnancy outcomes.
Main outcome measures  Total and unexplained stillbirth.
Results  The antepartum stillbirth rate was 3.0/1000 in the previous caesarean section group compared with 2.7/1000 in the previous vaginal delivery group ( P = 0.46). Multivariate logistic regression modelling, including terms for maternal age (polynomial), weight >91 kg, smoking during pregnancy, pre-pregnancy hypertension and diabetes, did not document an association between previous caesarean section and unexplained antepartum stillbirth (OR 1.27, 95% CI 0.92–1.77).
Conclusion  Caesarean section in the first birth does not increase the risk of unexplained antepartum stillbirth in second pregnancies.     

Maternal and perinatal outcome in nulliparous women aged 35 and older

OBJECTIVE: To compare the maternal and perinatal outcome of nulliparous women 35 years and older at the time of delivery with nulliparous women 25-29 years old. METHODS: A retrospective review of maternal and newborn records of singleton gestations only for first birth in women aged 35 and older (study group n = 143) were compared with pregnancies of women aged 25-29 (control group, n = 148) delivered at the same period with respect to pregnancy complications and outcome. The study was performed at the Princess Badeea Teaching Hospital in North Jordan between January 1, 1996 and July 1, 2000. RESULTS: Most of the elderly nulliparous women were professionals (60%) and 20% had a history of infertility. Compared with women aged 20-29 years, women delivering their first child at or >35 years were at increased risk of weight gain, obesity, chronic and pregnancy-induced hypertension, antepartum haemorrhage, multiple gestation, malpresentation, and premature rupture of membranes. Women aged 35 years and older were also substantially more likely to have preterm labour, oxytocin use, and caesarean births. The older women differed significantly in neonatal outcomes: gestational age, birth weight, preterm delivery, low birth weight, small for gestational age, fetal distress and neonatal intensive care unit admissions. CONCLUSION: It is concluded that nulliparous women 35 years and older had higher risk of antepartum, intrapartum, and neonatal complications than nulliparous women aged 25-29 years, but these risks, for the most part, are manageable in the context of modern obstetrics. The excess rate of caesarean sections is only partially accounted for by gestational complications. Despite the increased risk of complications, perinatal death of the study group was similar to that of the control group. There were no maternal deaths.     

Cannabis Use in Pregnancy in British Columbia and Selected Birth Outcomes

ObjectiveThis study sought to determine the association between cannabis use in pregnancy and stillbirth, small for gestational age (SGA) (<10th percentile), and spontaneous preterm birth (<37 weeks).MethodsThe study used abstracted obstetrical and neonatal medical records for deliveries in British Columbia from April 1, 2008 to March 31, 2016 that were contained in the Perinatal Data Registry of Perinatal Services British Columbia. Chi-square tests were conducted to compare maternal sociodemographic characteristics by cannabis use. Logistic regression was conducted to determine the association between cannabis use and SGA and spontaneous preterm births. Cox proportional hazards regression modelling was used to identify the association between cannabis use and stillbirth. Secondary analyses were conducted to ascertain differences by timing of stillbirth (Canadian Task Force Classification II-2).ResultsMaternal cannabis use has increased in British Columbia over the past decade. Pregnant women who use cannabis are younger and more likely to use alcohol, tobacco, and illicit substances and to have a history of mental illness. Using cannabis in pregnancy was associated with a 47% increased risk of SGA (adjusted OR 1.47; 95% CI 1.33–1.61), a 27% increased risk of spontaneous preterm birth (adjusted OR 1.27; 95% CI 1.14–1.42), and a 184% increased risk of intrapartum stillbirth (adjusted HR [aHR] 2.84; 95% CI 1.18–6.82). The association between cannabis use in pregnancy and overall stillbirth and antepartum stillbirth did not reach statistical significance, but it had comparable point estimates to other outcomes (aHR 1.38; 95% CI 0.95–1.99 and aHR 1.34; 95% CI 0.88–2.06, respectively).ConclusionCannabis use in pregnancy is associated with SGA, spontaneous preterm birth, and intrapartum stillbirth.     

Late stillbirths and long-term mortality of mothers

OBJECTIVE: To assess whether women who experienced stillbirths have an excess risk of long-term mortality. METHODS: We conducted a cohort study in the setting of the Jerusalem Perinatal Study, a population-based database of all births to West Jerusalem residents. Through data linkage with the Israeli Population Registry, we followed mothers who gave birth at least twice between 1964 and 1976 and compared the survival of women who had at least one stillbirth (n=595) with that of women who had only live births (n=24,523), using Cox proportional hazards models. RESULTS: During the study period, 78 (13.1%) mothers with stillbirths died, compared with 1,518 (6.2%) women without stillbirth (crude hazard ratio 2.08, 95% confidence interval [CI] 1.65-2.61). The mortality risk remained significantly increased after adjustments for sociodemographic variables, maternal diseases at pregnancy, placental abruption, and preeclampsia (hazard ratio 1.40, 95% CI 1.11-1.77). Stillbirth was associated with an increased risk of death from coronary heart disease (adjusted hazard ratio 2.00, 95% CI 1.02-3.93), all circulatory (adjusted hazard ratio 1.70, 95% CI 1.02-2.84) and renal (adjusted hazard ratio 4.70, 95% CI 1.47-15.0) causes. Stratifying by country of origin, an increased risk was evident particularly among women of North African origin (all-cause mortality, adjusted hazard ratio 2.47, 95% CI 1.69-3.63). CONCLUSION: Stillbirth may be a risk marker for premature mortality among parous women.     

Smoking-associated fetal morbidity among older gravidas: a population study

BACKGROUND: We set out to assess the influence of advanced maternal age on fetal morbidity associated with smoking during pregnancy in a population-based retrospective study of 7 792 990 singleton live births between 1995 and 1997 in the United States with documented maternal smoking habit. METHODS: The study group consisted of infants born to mothers aged>or=40 years (older mothers). Two maternal age categories (20-29, "younger mothers"; 30-39, "mature mothers") were constructed as comparison groups. Adjusted odds ratios (ORs) generated from logistic regression models were used to compare fetal morbidity indices associated with smoking across maternal age categories. Main outcome measures included preterm, very preterm, and small for gestational age (SGA). RESULTS: The prevalence of smoking was 13.1%, and decreased with increasing maternal age. Regardless of maternal age, the risk for fetal morbidity was significantly elevated if the mother smoked. The risks for preterm and SGA associated with smoking were significantly higher among older gravidas as compared to younger mothers while mature mothers had risk estimates comparable to those of older mothers. Among smoking mothers only, the risk pattern for fetal morbidity was J-shaped, with babies of older smokers having significantly higher fetal morbidity indices, while those of mature smokers showed lower levels of risk as compared to younger mothers. CONCLUSION: In an era of relatively lower prevalence of smoking during pregnancy, advanced maternal age still increases the risk of smoking-associated fetal morbidity. Our findings reveal new information of elevated risk for very preterm births among older smoking mothers.     

Maternal risk factors associated with fetal death during antenatal care in low-resource tertiary hospitals

BACKGROUND: Data on maternal characteristics that could predict antepartum fetal death in women receiving antenatal care in resource-constrained settings are limited. Aims: To identify maternal sociodemographic and clinical risk factors for antepartum fetal death among women receiving antenatal care in a developing country setting. METHODS: Case-control analyses of risk factors in the occurrence of singleton fetal death before labour at two university hospitals in south-west Nigeria over 4-5 years. A total of 46 cases and 184 controls were compared for 31 sociodemographic and clinical risk factors. Unconditional multivariate logistic regression analysis was applied to determine independent risk factors. Level of significance was set at P < 0.05. RESULTS: The incidence of antepartum fetal death among women receiving antenatal care was 10.8 per 1000 total births during the period. Significant risk factors at univariate level include proteinuria, pregnancy-induced hypertension, pre-existing hypertension, reduced weight gain per week, previous antepartum fetal death, antepartum haemorrhage, previous miscarriage, symphysiofundal height-gestational age disparity = 4 cm and perception of reduced fetal movements. The independent risk factors were proteinuria (adjusted OR 4.23, CI: 1.57-11.42), pregnancy-induced hypertension (adjusted OR 8.24, CI: 3.01-22.51) and perceived reduction in fetal movements (adjusted OR 7.17, CI: 1.57-45.76). CONCLUSIONS: The identified factors should serve as potential targets for antenatal interventions to prevent antepartum fetal death in these institutions. Awareness of these factors should stimulate appropriate risk assessment geared towards the prevention of antepartum fetal deaths by clinicians in these centres and centres in similar setting.     

Life-table analysis of the risk of perinatal death at term and post term in singleton pregnancies

OBJECTIVE: This study was undertaken to estimate the cumulative risk of perinatal death associated with delivery at each gestational week both at term and post term. STUDY DESIGN: The numbers of antepartum stillbirths, intrapartum stillbirths, neonatal deaths, and surviving neonates delivered at between 37 and 43 weeks' gestation in Scotland, 1985-1996, were obtained from national databases (n = 700,878) after exclusion of multiple pregnancies and deaths caused by congenital abnormality. The numbers of deaths at each gestational week were related to appropriate denominators: antepartum stillbirths were related to ongoing pregnancies, intrapartum stillbirths were related to all births (excluding antepartum stillbirths), and neonatal deaths were related to live births. The cumulative probability of perinatal death associated with delivery at each gestational week was estimated by means of life-table analysis. RESULTS: The gestational week of delivery associated with the lowest cumulative risk of perinatal death was 38 weeks' gestation, whereas the perinatal mortality rate was lowest at 41 weeks' gestation. The risk of death increased more sharply among primigravid women after 38 weeks' gestation because of a greater risk of antepartum stillbirth. The relationships between risk of death and gestational age were similar for the periods 1985-1990 and 1991-1996. CONCLUSION: Delivery at 38 weeks' gestation was associated with the lowest risk of perinatal death.