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.     

Increased risk in the elderly parturient

PURPOSE OF REVIEW: The steady increase in age in primiparous and multiparous women raises questions concerning increased obstetric risk and outcome in such pregnancies. This review highlights the effects of maternal age on obstetric and perinatal outcome. RECENT FINDINGS: Complications have been associated with increasing maternal age, including abnormal weight gain, obesity, gestational diabetes, chronic and pregnancy-induced hypertension, antepartum haemorrhage, placenta praevia, multiple gestation, prelabour rupture of membranes, and preterm labour. Intrapartum complications of malpresentation, fetopelvic disproportion, abnormal labour, increased use of oxytocin in labour, caesarean section, instrumental delivery, sphincter rupture, and postpartum haemorrhage are more frequent in older women. Advanced maternal age is associated with a higher risk of stillbirth throughout gestation, and the peak risk period is 37-41 weeks. Perinatal outcomes differ with maternal age concerning gestational age, birth weight, prematurity, low birth weight, incidence of small-for-gestational-age infants, fetal distress, and perinatal morbidity and mortality. The increased risk cannot be explained only by intercurrent illness or pregnancy complications. SUMMARY: Increasing maternal age is independently associated with specific adverse outcomes. Increasing age is a continuum rather than threshold effect. More information about obstetric consequences of delayed childbearing is needed both for obstetricians and fertile women.     

Advanced maternal age and risk of antepartum and intrapartum stillbirth

AIM: We sought to assess the risk of antepartum and intrapartum stillbirth subtypes among women of advanced age. METHODS: This is a retrospective cohort study using the Missouri maternally linked data containing births from 1978 to 1997. We examined the impact of maternal age on total, antepartum and intrapartum stillbirth across five maternal age group quintiles (20-24, 25-29, 30-34, 35-39 and >or=40) using mothers aged 20-24 years as the referent category. By means of the Cox proportional hazards regression models we obtained adjusted hazards ratios that quantified the magnitude of association between maternal age and the stillbirth subtypes. RESULTS: The rates of antepartum and intrapartum stillbirth were greatest for older mothers (9.3/1000 and 1.2/1000 respectively) and lowest for gravidas aged 25-29 years (3.6/1000 and 0.8/1000 respectively). After adjusting for potentially confounding characteristics, older mothers still remained at greatest risk for antepartum and intrapartum stillbirth (adjusted hazards ratio = 3.6, 95% confidence interval = 2.9-4.4; and adjusted hazards ratio = 2.7, 95% confidence interval = 2.0-3.6 for antepartum and intrapartum stillbirth respectively). The risks for the two subtypes of stillbirth also increased with ascending maternal age in a dose-dependent pattern. CONCLUSIONS: As the demographic distribution of pregnant women persistently shifts to the right, care-providers will be increasingly confronted with elevated risks for adverse fetal outcomes among older mothers. Our results confirm this phenomenon and add new findings in relation to the elevated risk for intrapartum stillbirth among mothers advanced for age.     

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.     

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.     

Indicators for intervention during the expulsive second-stage arrest of labour

Objective  To identify antepartum and intrapartum indicators of obstetric interventions during the expulsive second-stage arrest of labour.
Design  Retrospective cohort study.
Setting  The Netherlands.
Population  A cohort of 389 086 women with singleton, cephalic, term, live-birth deliveries from 2002 to 2004 who had entered the expulsive second stage of labour. Of all these deliveries, 37 899 (9.7%) were complicated by expulsive second-stage arrest of labour. Women with a prior Caesarean section or women undergoing an elective Caesarean section were excluded.
Methods  All deliveries in the Netherlands from 2002 to 2004 were registered in the Netherlands Perinatal Registry, which contains the linked and validated data of three databases. Uni- and multivariable logistic regression analyses were performed.
Main outcome measures  Ante- and intrapartum indicators for interventions during expulsive second-stage arrest of labour.
Results  Primiparous delivery was the most important antepartum indicator for intervention during expulsive second-stage arrest. Using multivariable analysis the following antepartum indicators were associated with intervention for expulsive second-stage arrest of primiparous labour: maternal age, gestational age, diabetes, hypertension and labour induction. Prominent intrapartum indicators for primiparous deliveries were fetal head position and oxytocin augmentation.
Conclusion  Multiple significant antepartum and intrapartum indicators associated with intervention for expulsive second-stage arrest of labour were identified in this large retrospective study. Prominent were the associations of parity, maternal age and fetal head position with expulsive second-stage arrest. The identified factors should be further evaluated in prospective studies that aim to develop prediction models.     

The influence of changing post-term induction of labour patterns on severe neonatal morbidity

ObjectiveTo estimate the influence of changing practice patterns of post-term induction of labour on severe neonatal morbidity.MethodsThis population-based cohort study used data from the Nova Scotia Atlee Perinatal Database to evaluate the effect of post-term induction of labour on stillbirth and neonatal mortality and severe neonatal morbidity in low-risk pregnancies. The study population included all pregnant women ≥ 40 weeks’ gestation delivering in Nova Scotia from 1988 to 2008 who underwent induction of labour with a single fetus in cephalic presentation. Major congenital anomalies and pre-existing or severe gestational hypertension and diabetes were excluded. Women delivering post-term from 1994 to 2008 (after the Post-term Pregnancy Trial) were compared with women delivering from 1988 to 1992 to evaluate outcomes with changing maternal characteristics and obstetric practice patterns.ResultsEvaluation and comparison of time epochs (1988 to 1992, 1994 to 1998, 1999 to 2003, and 2004 to 2008) demonstrated an increased risk for perinatal mortality or severe neonatal morbidity, especially low five-minute Apgar score, among both nulliparous and multiparous women. There were no significant differences in the risks for stillbirth or perinatal mortality over time. Comparable relationships were demonstrated in a subgroup of lower risk women.ConclusionThe increase in post-term induction of labour with time is associated with a significant increase in severe neonatal morbidity, especially among infants born to multiparous women. Evaluation of the antepartum and intrapartum management of these low-risk pregnancies may provide additional information to reduce morbidity.     

Maternal age ≥45 years and maternal and perinatal outcomes: A review of the evidence

Objective

to examine the evidence in relation to very advanced maternal age (≥45 years) and maternal and perinatal outcomes in high-income countries.

Background

this review was conducted against a background of increasing fertility options for women aged ≥=45 years and rising birth rates among this group of women.

Methods

established health databases including SCOPUS, MEDLINE, CINAHL, EMBASE and Maternity and Infant Care were searched for journal papers, published 2001–2011, that examined very advanced maternal age (VAMA) and maternal and perinatal outcomes. Further searches were based on references found in located articles. Keywords included a search term for maternal age ≥45 years (very advanced maternal age, pregnancy aged 45 years and older) and a search term for maternal complications (caesarian section, hypertension, pre-eclampsia, gestational diabetes) and/or adverse perinatal outcome (preterm birth, low birth weight, small for gestational age, stillbirth, perinatal death). Of 164 retrieved publications, 10 met inclusion criteria.

Data extraction

data were extracted and organised under the following headings: maternal age ≥45 years; maternal characteristics such as parity and use of artificial reproductive technology (ART); and pre-existing maternal conditions, such as diabetes and hypertension. Additional headings included: gestational conditions, such as pre-eclampsia and gestational diabetes (GDM); and perinatal outcomes, including fetal/infant demise; gestational age and weight. Study quality was assessed by using the Critical Appraisal Skills Programme (CASP) guidelines.

Findings

this review produced three main findings: (1) increased rates of stillbirth, perinatal death, preterm birth and low birth weight among women ≥45 years; (2) increased rates of pre-existing hypertension and pregnancy complications such as GDM, gestational hypertension (GH), pre-eclampsia and interventions such as caesarian section; and (3) a trend of favourable outcomes, even at extremely advanced maternal age (50–65 years), for healthy women who had been screened to exclude pre-existing disease.

Key conclusions

although there is strong evidence of an association between very advanced maternal age and adverse maternal and perinatal outcomes, the absolute rate of stillbirth/perinatal death remains low, at less than 10 per 1000 births in most high-income countries. Therefore, although women in this age group encounter greater pregnancy risk, most will achieve a successful pregnancy outcome. Best outcomes appear to be linked to pre-existing maternal health, and pregnancy care at tertiary centres may also contribute. This information should be used to counsel women aged ≥45 years who are contemplating pregnancy.     

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.     

Alloimmunization in twin pregnancies

Among 7052 patients studied between 1976 and 1982 in a collaborative project on antepartum fetal heart rate monitoring, 337 patients had a previous stillbirth as a reason for testing. Overall a previous stillbirth history significantly increased the risk of having a positive result on a contraction stress test, primarily among hypertensive patients. Patients with a previous stillbirth also had a significantly higher incidence of respiratory distress syndrome in their neonates attributable to premature intervention for maternal indications (primarily among hypertensive women and patients with clinical intrauterine growth retardation). Low Apgar scores were found to be significantly increased in diabetics with previous stillbirths primarily due to neonates with congenital malformations. Premature intervention by labor induction or cesarean section was more common among patients with a previous stillbirth for both maternal indications and abnormal antepartum fetal heart rate studies. Previous stillbirth would appear therefore to be a significant risk factor primarily when associated with a diagnosis of hypertension or clinical intrauterine growth retardation.     

Restricted fetal growth in sudden intrauterine unexplained death

BACKGROUND: Unexplained antepartum stillbirth is a common cause of perinatal death, and identifying the fetus at risk is a challenge for obstetric practice. Intrauterine growth restriction (IUGR) is associated with a variety of adverse perinatal outcomes, but reports on its impact on unexplained stillbirths by population-based birthweight standards have been varying, including both unexplained and unexplored stillbirths. AIM: We have studied IUGR, assessed by individually adjusted fetal weight standards, in antepartum deaths that remained unexplained despite thorough postmortem investigations. METHODS: Antenatal health cards from a complete population-based 10-year material of 76 validated sudden intrauterine unexplained deaths were compared to those of 582 randomly selected liveborn controls. Birthweight <10th percentile of the individualized standard adjusted for gestational age, maternal height, weight, parity, ethnicity, and fetal gender was defined as growth restriction. RESULTS: 52% of unexplained stillbirths were growth restricted, with a mean gestational age at death of 35.1 weeks. Suboptimal growth was the most important fetal determinant for sudden intrauterine unexplained death (odds ratio 7.0, 95% confidence interval 3.3-15.1). Concurrent maternal overweight or obesity, high age, and low education further increase the risk. Overweight and obesity increase the risk irrespective of fetal growth, and while high maternal age increases the risk of the normal weight fetus, it is not associated to growth restriction as a precursor of sudden intrauterine unexplained death. CONCLUSIONS: IUGR is an important risk factor of sudden intrauterine unexplained death, and this should be excluded in pregnancies with any other risk factor for sudden intrauterine unexplained death.     

Sudden fetal death in women with well-controlled, intensively monitored gestational diabetes.

An intensive antepartum monitoring system for women with gestational diabetes mellitus was evaluated over a 5-year period. Early diagnosis and liberal treatment with insulin was concomitantly followed with non-stress testing: weekly from 28 to 34 weeks' gestation and semi-weekly thereafter. Despite maternal euglycemia and satisfactory antepartum assessment, three fetal deaths occurred within 72 hours of reassuring fetal monitoring. Additionally, 24 (7%) fetuses were delivered on the basis of a low biophysical profile score (less than 6) at term. The stillbirth rate for women with gestational diabetes was 7.7/1000, whereas the stillbirth rate for nondiabetic low-risk patients was 4.8/1000. Women with gestational diabetes continue to be in a high-risk category for antepartum fetal death, requiring intensive monitoring with consideration for timely delivery.     

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.     

Stillbirths in Western Australia 1980–1983: Influence of Race, Residence and Place of Birth

All stillbirths in Western Australia from 1980-83 weighing 1,000 g and over were identified from perinatal death certificates, and their causes and demographic correlates described. The stillbirth rate was 4.91 per 1,000 total births; nearly 65% were antepartum, 25% intrapartum and in 10% the time of death was unknown. The cause of death of most stillbirths was unknown (52%) or associated with lethal congenital malformations (13%), antepartum haemorrhage (12%) or maternal hypertension (8%). Whilst Aboriginal women had much higher stillbirth rates (10.80) than non-Aboriginal women (4.57), their patterns of time and causes of death were similar. Both antepartum and intrapartum stillbirth rates were much higher at low birth-weights and low gestational ages in both racial groups. Women living in rural areas who delivered in the metropolitan area had much higher antepartum (11.02) and intrapartum (3.31) stillbirth rates than either rural women delivering in rural areas (1.89 and 1.34) or metropolitan women delivering in the metropolitan area (2.72, 0.98). This reflects the transfer of rural high risk pregnant women or those with fetal death in utero, for delivery in metropolitan specialist hospitals.     

Previous caesarean or vaginal delivery: Which mode is a greater risk of perinatal death at the second delivery?

OBJECTIVE: To compare the risk of perinatal death after previous caesarean versus previous vaginal delivery, and pre-labour repeat caesarean versus trial of labour after previous caesarean. STUDY DESIGN: Using the data of the Berlin Perinatal Registry from 1993 to 1999, 7556 second parous women with a previous caesarean delivery were compared with 55142 second parous women with a previous vaginal delivery, and those 1435 women with pre-labour repeat caesarean were compared with 6121 women with a trial of labour after previous caesarean delivery. The rates of perinatal death, stillbirth and intrapartum/neonatal death were analysed using multivariable logistic regression to adjust for confounding variables and obstetric history. RESULTS: A previous caesarean delivery was associated with a 40% excess risk of perinatal death and a 52% excess risk of stillbirth (p<0.05); the risk of intrapartum/neonatal death was not significantly increased. There were no significantly higher rates of intrapartum/neonatal death and of stillbirth in women trying a vaginal birth versus pre-labour repeat caesarean. But in most cases of antepartum death, labour was induced for that reason. CONCLUSION: Consulting women about caesarean delivery for maternal request, the increased risk of perinatal death in further pregnancies should be discussed. After a previous caesarean delivery, a careful screening for several risk factors is necessary before recommending a trial of labour.     

Stillbirth: is it preventable?

In the UK stillbirth, describes the death of a baby before birth after 24 completed weeks of pregnancy. The rate has decreased in the UK over recent years but at a slower pace than other similar high-income countries. The association of certain risk factors (including maternal age, previous poor obstetric outcome, smoking and obesity) is clearly documented, though only a number of these factors can be modified. Use of interventions including the ‘Saving Babies Lives’ Care Bundle focussing on smoking cessation, assessment for small for gestational age (SGA) babies, educating women regarding reduced fetal movements and effective fetal monitoring during labour aim to reduce both antenatal and intrapartum stillbirth. As yet, it remains difficult to predict which pregnancies are at greatest risk of stillbirth but with further research, ongoing improvements in antenatal and intrapartum care, and improved patient education, it is anticipated that the incidence in the UK can be substantially reduced.     

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.     

The analysis of factors predicting antepartum stillbirth

Antepartum stillbirth is the single most common cause of perinatal death. Antepartum stillbirth is associated with fetal abnormality, congenital infection, rhesus isoimmunisation, maternal medical conditions, and complications of pregnancy, such as pre-eclampsia and placental abruption. However, the majority have no direct obstetric cause and are referred to as unexplained. Many of these so-called unexplained deaths are associated with growth restriction. Maternal characteristics, such as age and smoking, are associated with an increased risk of antepartum stillbirth. The risk of stillbirth in late pregnancy is related to the function of the placenta in early pregnancy. Placental function can be assessed using circulating markers in the mothers blood, such as pregnancy associated plasma protein A and alpha-fetoprotein. Invasion of the trophoblast into the uterine vessels is associated with decreased resistance to flow in the uterus and impaired placentation is reflected in high resistance Doppler flow velocity waveforms in the utero-placental circulation. Both circulating placental markers and Doppler indices of resistance to flow are predictive of the risk of antepartum stillbirth. However, none of these tools has sufficient positive predictive value to justify population based screening. Future research in unexplained stillbirth should be directed towards developing better predictive tests to identify women at high risk and the evaluation of interventions in large scale trials.     

Stillbirth and neonatal outcomes in South Australia, 1991-2000

OBJECTIVES: The purpose of this study was to determine the effect of maternal factors associated with impaired placental function on stillbirth and neonatal death rates in South Australia. STUDY DESIGN: From 1991 to 2000, the South Australian Pregnancy Outcome Unit's population database was searched to identify stillbirths and neonatal deaths in women with maternal medical conditions during pregnancy and in twin and singleton pregnancies. RESULTS: Women with hypertension and carbohydrate intolerance and who smoked during pregnancy had an increased risk of stillbirth. Women with twin pregnancies had a significantly higher stillbirth rate than for singletons at each week of gestational age. An increase in stillbirth rate at later gestations was seen with singletons, with a similar trend in twins but rising from 36 weeks' gestation. CONCLUSION: There is a clinical correlation between maternal factors associated with impaired placental function and increased risk of stillbirth, suggesting that intrauterine fetal death represents the mortality end point in a spectrum of intrauterine hypoxia.     

Understanding perinatal mortality

The term perinatal death is used to describe antepartum and intrapartum stillbirths, and early neonatal deaths. At term, intrapartum stillbirth and neonatal death are collectively referred to as delivery related perinatal death, and the incidence in nulliparous and multiparous women is approximately one in 1000 and one in 2000 births, respectively. Associated factors include advanced maternal age, small for gestational age, fetal macrosomia, breech labour and previous caesarean delivery. The impact of obstetric interventions in labour on delivery related perinatal death, including rising rates of caesarean delivery, is complex and unclear. The incidence of overall perinatal death is falling mainly as a result of improvements in the management of premature neonates and from decreased deaths secondary to intrapartum anoxia at term. This review will provide an overview of perinatal mortality with a particular emphasis on delivery related perinatal death at term.