11. Perinatal mortality

Summary. The perinatal mortality rate in all singleton births was 103 per 1000; 67% of all perinatal deaths were stillbirths and in 77% of stillbirths, intrauterine death had already occurred before admission to hospital. Nine per cent of live births but 40% of stillbirths and 50% of neonatal deaths were of low birthweight (≤2.5 kg). The principal obstetric causes of perinatal deaths were obstructed labour and its consequences, anaemia, antepartum haemorrhage, eclampsia and low fetal birthweight. Nearly half of all perinatal deaths were associated with complicated deliveries of which vaginal breech delivery was by far the most hazardous. Both the proportion of babies with low birthweight and the perinatal mortality rates rose dramatically and progressively with haematocrit <0.30. A raised perinatal mortality rate was also associated with raised haematocrit >0.40. Of the biosocial factors influencing perinatal health, lack of antenatal care, residence outside Zaria, early teenage pregnancy and high parity exerted the most deleterious effect and literacy and antenatal care the most favourable effect on pregnancy outcome.     

Obstetric diagnosis and perinatal mortality

A multidisciplinary team composed of obstetricians, pediatricians, and pathologists examined the causes of 453 consecutive perinatal deaths, which occurred between 1978 to 1982. A clear distinction between obstetric diagnosis and infant cause of death was made, and a prinicpal obstetric and infant diagnosis was assigned to each death. Perinatal death rates by obstetric category were calculated. The rates varied from 6.1 per 1000 births in uncomplicated cases to 217.4 per 1000 births in isolated intrauterine growth retardation. The causes of perinatal death within obstetric categories were tabulated. Nonviability or the complications of prematurity (65%) were the leading causes of death when there was third-trimester bleeding, premature labor, or premature rupture of membranes. Anoxia (59%) was the most frequent cause of death when there was hypertension/pre-eclampsia or other uteroplacental insufficiency states. Death from congenital abnormality accounted for 17.7% of all perinatal deaths. A focus on the causes of perinatal death with obstetric diagnostic categories helps weigh the risk of prematurity versus the risk of anoxia in the management of high-risk gravidas.     

Physician- and midwife-attended home births Effects of breech,twin, and post-dates outcome data on mortality rates

The effect of attending breech, twin, and post-date pregnancies on home birth outcomes was assessed. The same form was used to collect data on a convenience sample of 4,361 home births attended by apprentice-trained midwives from 1970 to 1985 and 4,107 home births attended by family physicians from 1969 to 1981. Data sets were compared to find 1,000 pairs of pregnant women, one from each group, who were matched for age, sex, socioeconomic status, race, and medical risk. The perinatal mortality rate for the midwife-attended births was 14 per 1,000 (three fetal deaths before labor, six intrapartum fetal deaths, and five neonatal deaths). The perinatal mortality rate for births attended by family physicians was five per 1,000 (one fetal death before labor, two intrapartum fetal deaths, and two neonatal deaths). The difference was statistically significant; however, the differences disappeared when cases involving post-dates, twin, or breech deliveries were eliminated from the sample. Although the data are more than a decade old, they support the premise that outcomes for low-risk home births are comparably good whether attended by physicians or midwives. However, the findings do raise questions about the safety of attending high-risk births at home.     

PHYSICIAN- AND MIDWIFE-ATTENDED HOME BIRTHS: Effects of Breech,Twin, and Post-Dates Outcome Data on Mortality Rates

The effect of attending breech, twin, and post-date pregnancies on home birth outcomes was assessed. The same form was used to collect data on a convenience sample of 4,361 home births attended by apprentice-trained midwives from 1970 to 1985 and 4,107 home births attended by family physicians from 1969 to 1981. Data sets were compared to find 1,000 pairs of pregnant women, one from each group, who were matched for age, sex, socioeconomic status, race, and medical risk. The perinatal mortality rate for the midwife-attended births was 14 per 1,000 (three fetal deaths before labor, six intrapartum fetal deaths, and five neonatal deaths). The perinatal mortality rate for births attended by family physicians was five per 1,000 (one fetal death before labor, two intrapartum fetal deaths, and two neonatal deaths). The difference was statistically significant; however, the differences disappeared when cases involving post-dates, twin, or breech deliveries were eliminated from the sample. Although the data are more than a decade old, they support the premise that outcomes for low-risk home births are comparably good whether attended by physicians or midwives. However, the findings do raise questions about the safety of attending high-risk births at home.     

The impact of prenatal care on neonatal deaths in the presence and absence of antenatal high-risk conditions

OBJECTIVE: The purpose of this study was to determine the association between prenatal care in the United States and the neonatal death rate in the presence and absence of antenatal high-risk conditions. STUDY DESIGN: Data were derived from the national perinatal mortality data sets for the years 1995 through 1997, which were provided by the National Center for Health Statistics. Analyses were restricted to singleton live births that occurred after 23 completed weeks of gestation. Multivariable logistic regression analyses were used to adjust for the presence or absence of various antenatal high-risk conditions, maternal age, gestational age at delivery, and birth weight. RESULTS: Of 10,530,608 singleton live births, 18,339 (1.7/1000 births) resulted in neonatal death. Neonatal death rates (per 1000 live births) were higher for African American infants compared with white infants in the presence (2.7 vs 1.5, respectively) and absence (10.7 vs 7.9, respectively) of prenatal care. Lack of prenatal care was associated with an increase in neonatal deaths, which was greater for infants born at > or =36 weeks of gestation (relative risk, 2.1; 95% CI, 1.8, 2.4). Lack of prenatal care was also associated with increased neonatal death rates in the presence of preterm premature rupture of the membranes (relative risk, 1.3; 95% CI, 1.1, 1.5), placenta previa (relative risk, 1.9; 95% CI, 1.2, 2.9), fetal growth restriction (relative risk, 1.7; 95% CI, 1.2, 1.6), and postterm pregnancy (relative risk, 1.4; 95% CI, 1.0, 2.9). CONCLUSION: In the United States, prenatal care is associated with fewer neonatal deaths in black and white infants. This beneficial effect was more pronounced for births that occurred at > or =36 weeks of gestation and in the presence of preterm premature rupture of the membranes, placenta previa, fetal growth restriction, and postterm pregnancy.     

Analysis of 65 cases of abruptio placenta]

From Jan 1, 1971 to Dec 12, 1990, 65 cases of abruptio placenta were admitted to our hospital. The incidence was 0.19%. Among them, thirty were complicated by pregnancy induced hypertension (46.2%). The perinatal fetal mortality was 19.7%; perinatal death occurred mostly in the premature group. All babies survived except two abnormalities. Cesarean section rate was 32.3%. All postpartum hemorrhage 29.2%. Couvelaire uterus 6.2%, were cured by conservative treatment. There was neither stillbirth nor newborn death in the thirty three cases treated expectant, but a newborn asphyxia rate of 6.1% and a cesarean section rate of 15.1%. Analysis showed that abruptio placentae should be suspected in cases with abnormal fetal heart rate of unknown cause accompanying signs of labor, premature labor of unknown cause, uterine tongue, ultrasonically visualized liquid from dark area behind the placenta, besides classical signs of abdominal pain and vaginal bleeding. Expectant treatment is appropriate if gestational age is small and no acute symptoms exists so as to minimize the perinatal mortality and cesarean section rate.     

Systematic multidisciplinary approach to reporting perinatal mortality: Lessons from a five-year regional review

Background:  Because of differences in reporting criteria throughout the world, comparing perinatal mortality rates and identifying areas of concern can be complicated and imprecise.
Aims:  To detail the systematic approach to reporting perinatal deaths and to identify any significant differences in outcomes in the Australian Capital Territory (ACT).
Methods:  Review of perinatal deaths from 2001 to 2005 in the ACT using the Australian and New Zealand Antecedent Classification of Perinatal Mortality (ANZACPM) and the Australian and New Zealand Neonatal Death Classification (ANZNDC) systems.
Results:  ACT residents' perinatal mortality rate was 10.6 per 1000 total births, fetal death rate 7.5 per 1000 total births and neonatal death rate 3.2 per 1000 live births. The three leading antecedent causes of perinatal death were congenital anomalies, spontaneous preterm birth and unexplained antepartum death. The three leading causes of neonatal death were extreme prematurity, cardiorespiratory disorders and congenital anomalies. Multiple births attributed to 20% (65 of 321) of perinatal deaths. Perinatal autopsy was performed in 50% of cases, but in only 64% of unexplained antepartum deaths.
Conclusions:  Causes of perinatal death for the ACT and surrounding New South Wales region are similar to other states using this classification system. The following are considered important lessons to promote accurate perinatal mortality reporting: (i) a universal reporting system for Australia utilising a multidisciplinary team; (ii) a high perinatal autopsy rate, especially in the critical area of antepartum death with no identifiable cause; and (iii) standardised definitions for avoidability. Attention to these areas may prompt further research and changes in practice to further reduce perinatal mortality.     

Evaluation of a feto-pelvic scoring system in the management of breech presentations

A feto-pelvic scoring system comprising maternal pelvimetric data, estimated fetal weight, type of breech presentation and previous obstetric history was used in selecting patients for cesarean section of vaginal delivery. A maximum score of 20 points was possible. Twelve points or less indicated cesarean section. During 1973-1975 224 singleton breech deliveries were evaluated. In 29.5% cesarean section was performed and in 83% of these it could be planned in advance. In 70.5% of cases, patients were allowed to deliver vaginally under continuous electronic monitoring of the fetal heart rate. There was one intrapartum death and only one early neonatal death of a small premature child. In two cases intrauterine death had occurred already in the antepartum period. The uncorrected perinatal mortality was 17.9 per 1000 but not significantly different from the uncorrected perinatal mortality of 8.0 per 1000 for all patients delivered at the Danderyd's Hospital during the period 1972-1975 (12832 births). The corrected mortality resulting from breech presentation was 8.9 per 1000. The infants exhibited similar and excellent 5 min Apgar scores whether delivered vaginally or by cesarean section or matched with a randomized control series of 1000 cephalic presentations.     

Fetal death during labor: an epidemiologic indicator of level of obstetric care

The effect of level of perinatal care on rates of intrapartum fetal death was studied in births of infants weighing greater than 1000 gm in New York City in 1976 to 1978. With potential confounding by birth weight, gestational age, and several other variables controlled, intrapartum fetal death rates decreased as intensiveness of care increased. Compared with births in Level 3 maternity units (perinatal intensive care), births in Level 1 units (community hospitals) had a 61% excess risk of intrapartum fetal death (p less than 0.01) and births in Level 2 units (intermediate level of care) had a 35% excess risk (p = 0.06). The effect of hospital level on intrapartum fetal death rates could not be attributed to differences in the classification of fetal deaths during labor across hospital levels, since no compensatory differences in late antepartum fetal death rates were found. Our findings in a total population are compatible with several studies carried out in single hospitals that have reported declines in intrapartum fetal death rates, especially in births more closely attended during labor. Fetal deaths that occur in labor, as contrasted with fetal deaths occurring before labor, constitute a perinatal outcome that is especially sensitive to level of obstetric care.     

Clinical causes and classification of perinatal mortality in Lagos

Perinatal deaths in singleton births at the Lagos University Teaching Hospital during a 5-year period were reviewed. Causes of deaths were classified into eight groups using a modified form of the Aberdeen classification. Perinatal mortality was high (42.5/1000 total births). The stillbirth rate was 32.5/1000 total births. The major causes of perinatal mortality were trauma (30.5%), low birth weight (23.9%), hemorrhage (13.7%), toxemia of pregnancy (10.3%) and mature, cause unknown (10%). Congenital malformation (4.3%) was not a major cause of perinatal deaths in this study.     

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.     

An assessment of key aetiological factors associated with preterm birth and perinatal mortality.

The 4 main causes of preterm births in 303 women with consecutive deliveries in Flinders Medical Centre were premature rupture of the membranes (39%), spontaneous preterm labour (22%), pregnancy-induced hypertension (17%) and antepartum haemorrhage (12%). Premature rupture of the membranes occurred with equal frequency in singleton and multiple pregnancies and there was no difference in the frequency of this cause between the pregnancies with live outcomes and those with perinatal deaths. Spontaneous preterm labour was more common in multiple pregnancies (39%) than in singleton pregnancies (22%). One in 3 of the preterm births and 79% of the pregnancies with perinatal deaths occurred at less than 32 weeks' gestation. As it is unlikely that any single obstetric and social intervention will be able to reduce these causes of preterm birth research must continue to find markers to predict premature rupture of the membranes and spontaneous preterm labour.     

Perinatal mortality in a large perinatal center: five-year review of 31,000 births

The perinatal mortality rate for 30,928 babies born at Medical Center Hospital, San Antonio, Texas, between 1978 and 1982, was 20.3/1,000 births. Neonatal and fetal mortality rates were, respectively, 10.1/1,000 live births and 10.4/1,000 births. Exclusion of babies who weighed less than 500 gm yielded adjusted fetal, neonatal, and perinatal mortality rates of, respectively, 9.2, 9.8, and 17.9. Birth weight-specific mortality rates were calculated by groups of 250 gm birth weight for all neonates and by increments of 100 gm for babies who weighed 500 to 1,499 gm. Male infants, intrauterine growth-retarded babies, and babies whose mothers were less than 15 years old contributed more deaths than would be expected from the characteristics of the obstetric population. Presumptive cause of fetal death was unknown in 32%, fetal anoxia in 21%, maternal pathologic conditions in 20%, inappropriate fetal growth in 13%, congenital malformations in 8%, and systemic fetal infections in 6%. Leading presumptive causes of neonatal death were immaturity (29%), congenital malformations (18%), hemorrhages (16%), and systemic infections (10%). Hyaline membrane disease and necrotizing enterocolitis contributed, respectively, 7% and 6% of deaths. Past and future trends of perinatal mortality are discussed.     

The preterm breech delivery in Zaria, northern Nigeria.

The preterm breech occurred in 31.21% of singleton breech presentations in a prospective study at Ahmadu Bello University Teaching Hospital (ABUTH), Zaria, Nigeria. The uncorrected perinatal mortality of 670.5 per 1000 deliveries was 1.7 times that for term breech presentations. Failure to book for antenatal care (50.94%), admission of cases in the second stage of labor (21.84%) and intrauterine fetal death on admission (38.64%) were associated factors of the high perinatal mortality. The mortality was extremely high in the very low birthweight fetus (less than 1500 g) delivered vaginally. Moreover, the cesarean section rate was associated with a 2.4 times higher perinatal morbidity and mortality rates than vaginal delivery.     

Neonatal survival and perinatal factors in infants born at 24 to 32 weeks of gestation

Clinical associations between neonatal survival and perinatal factors were studied in very premature infants delivered at Kurashiki Central Hospital Perinatal Center during April 1979 to March 1983. The very premature singleton infants without congenital anomaly were studied in the present work, including 45 live-birth infants born at 24 to 32 weeks of gestation and weighing 590 to 2,000g at birth. The mortality rate for male infants was higher than that for female infants, but this difference was not statistically significant. The mortality rate for infants born at 28 to 32 weeks of gestation was 2.9%, and that for infants weighing 1,000g or more at birth, respectively. The cause of all these neonatal death was massive aspiration syndrome with intracranial hemorrhage, and severe neonatal asphyxia. The mortality rate for infants born at 24 to 32 weeks of gestation was 60%, and that of infants weighing 999g or less, 60%, respectively. The cause of all these neonatal deaths was respiratory distress syndrome with intracranial hemorrhage. Clinically, it was suggested that cesarean section after onset of labor, PROM, and Betamethasone prior to delivery increased the survival rate of these infants statistically significantly. The most important neonatal complication in the prognosis of very premature infants was intracranial hemorrhage. The most correlated perinatal factors of neonatal intracranial hemorrhage were one min. Apgar score and fetal lung maturation.     

Maternal estrogen excretion before perinatal death

As the value of urinary estrogen measurement in prevention of perinatal death has been questioned, a series of 626 consecutive perinatal deaths was studied to identify possible failures of the technique. 101 deaths related to singleton pregnancies during which urinary estrogen excretion had been measured; 32 deaths were preceded by normal estrogen excretion but no antepartum death from chronic placental failure occurred in this group, whereas 28 of the 69 deaths preceded by abnormal excretion were attributed to this cause. Most of these deaths were for various reasons regarded as unavoidable. There was one death possibly due to induction of labor done because of abnormal estrogen excretion. 4 deaths following abnormal results might have been avoided by appropriate action. 13 deaths might have been prevented if the assays had been performed in cases in which indications were present.It is concluded that urinary estrogen excretion is abnormal before fetal death from chronic placental failure. Other techniques to detect risk of fetal death have not undergone such extensive validation.     

Analysis of perinatal mortality at a teaching hospital in Dar es Salaam, Tanzania, 1999-2003

We conducted a retrospective analysis of perinatal mortality at Muhimbili National Hospital (MNH), Dar es Salaam, Tanzania 1999-2003 in order to categorise/classify perinatal deaths as well as to identify key factors in perinatal care that could be improved. Data were retrieved from the MNH obstetric database and causes of early neonatal deaths were traced from the neonatal ward register. The study includes all foetuses weighing =500g. A modified Nordic-Baltic classification was used for classification of perinatal deaths. Over a 5-year period there were 77,815 babies born with a perinatal mortality rate of 124 per 1000 births, 78% of which was labour related stillbirth. The PMR was 913/1000 for singleton births and 723/1000 for multiple births for babies weighing less than 1500 grams and 65/1000 for singleton births and 116/1000 for multiple births for babies weighing 2500 grams or more. Babies weighing less than 1500 grams contributed 26% of PMR, whereas 41% occurred in babies weighing 2500 grams or more. The majority (79%) of neonatal deaths had Apgar score <7 at 5 minutes and the most common causes of neonatal mortality were birth asphyxia (37%) and prematurity (29%). Labour related deaths were more common in multiple pregnancies. The majority of the perinatal deaths should be essentially avoidable through improved quality of intrapartum care. Establishment of perinatal audit at MNH can help identify key actions for improved care.     

Clinical significance of fetal heart rate patterns during labor. VIII. Breech presentations

The fetal heart rate (FHR) tracings of 302 consecutive breech presentations were analyzed to assess their potential value in clinical practice. There were 274 singleton births, 27 first twins and 1 triplet. Ten percent of the gestations were greater than or equal to 42 weeks, and 26% were less than or equal to 36 weeks. Infants premature by weight (less than 2,500 gm) made up 32%. Only 33.3% had no decelerations, and 63.0% had variable or variable-late decelerations. The latter group had a significantly higher incidence of depressed neonates and neonatal deaths. When accelerations were present, there were significantly fewer depressed infants and neonatal deaths. Overall the perinatal mortality (PNM) was 7.9%; for premature infants it was 27%, postterm 3% and term 1%. There was a 31% incidence of cesarean section. The PNM, when analyzed according to route of delivery, was no different for the very-low-birth-weight, low-birth-weight and term infants. Weight-specific mortality accounted for the apparent difference among the very-low-birth-weight infants. The high incidence and pathophysiology of cord compression (for first- and second-stage labor) may explain the higher incidence of depression in breeches as compared to cephalics. FHR monitoring should be done throughout delivery in order for the physicians to intervene on time when fetal distress is imminent.     

Diabetes in pregnancy: a population-based study of incidence, referral for care, and perinatal mortality

During 1979 and 1980 in Washington State, 260 infants (live births plus fetal deaths greater than or equal to 20 weeks' gestation) were born to women with preexisting diabetes mellitus, the equivalent to a population-based incidence of 2.1 per 1000 total births. One quarter of these women had non-insulin-dependent diabetes prior to pregnancy. The perinatal mortality rate for all infants of diabetic mothers in this series was 108 per 1000, which was eight times the state perinatal mortality rate. Only 45% of births occurred in the five tertiary centers in the state, whereas 39% occurred in hospitals that had fewer than six deliveries per year complicated by overt diabetes. The mortality rate was slightly, but not significantly, lower among infants born in referral hospitals than among those born in primary-level hospitals. Congenital malformations accounted for 43% of the 28 perinatal deaths, and fetal losses between 20 and 27 weeks' gestation accounted for another 21%. During the 2-year study period there were only three cases in which antepartum care in nonspecialty centers may have contributed to a perinatal loss.     

Nonintervention in premature rupture of the amniotic membranes

One hundred and forty-one instances of premature rupture of the amniotic membranes (PROM), between 25 and 36 weeks gestation and with duration of PROM greater than six hours, were managed by bedrest, observation and no obstetric intervention. Delivery was allowed if the patient had spontaneous labor develop, and delivery was initiated for chorioamnionitis or fetal distress. The perinatal mortality was 25 of 148 infants delivered (168 of 1,000 births). The majority of neonatal deaths (64 per cent) were attributable to complications of prematurity. Neonatal sepsis was uncommon as a cause of death (0.16 per cent). Results indicate that the natural history of PROM is associated with a low incidence of serious maternal and fetal infections and that prematurity is the most serious problem.