Singleton Stillbirths Research Articles

Customized birth weight for gestational age standards: Perinatal mortality patterns are consistent with separate standards for males and females but not for blacks and whites

BackgroundSome currently available birth weight for gestational age standards are customized but others are not. We carried out a study to provide empirical justification for customizing such standards by sex and for whites and blacks in the United States.MethodsWe studied all male and female singleton live births and stillbirths (22 or more weeks of gestation; 500 g birth weight or over) in the United States in 1997 and 1998. White and black singleton live births and stillbirths were also examined. Qualitative congruence between gestational age-specific growth restriction and perinatal mortality rates was used as the criterion for identifying the preferred standard.ResultsThe fetuses at risk approach showed that males had higher perinatal mortality rates at all gestational ages compared with females. Gestational age-specific growth restriction rates based on a sex-specific standard were qualitatively consistent with gestational age-specific perinatal mortality rates among males and females. However, growth restriction patterns among males and females based on a unisex standard could not be reconciled with perinatal mortality patterns. Use of a single standard for whites and blacks resulted in gestational age-specific growth restriction rates that were qualitatively congruent with patterns of perinatal mortality, while use of separate race-specific standards led to growth restriction patterns that were incompatible with patterns of perinatal mortality.ConclusionQualitative congruence between growth restriction and perinatal mortality patterns provides an outcome-based justification for sex-specific birth weight for gestational age standards but not for the available race-specific standards for blacks and whites in the United States.

Does the fetus lose weight in utero following fetal death: a study in preterm infants.

To evaluate whether the fetus loses weight in uttero following fetal death, looking specifically at weight differences according to whether the death occurred during labour or before labour. Record linkage of maternity data and perinatal mortality data. Scotland, UK. Population A group of 8,069 singleton live and stillbirths without obvious congenital abnormalities delivered at 24-32 weeks. Birthweight. Stillborn infants weighed less than liveborns of equivalent gestational age at delivery. Stillborn infants in whom the death occurred during labour weighed more than those in whom the death occurred before labour; this applied to both vaginal deliveries and those by caesarean section. These findings could be attributed to the hypothesis that the low birthweight of stillborn infants is due to weight loss following the death, in addition to any process of growth restriction before the death. The analysis described here contains no data which would negate this hypothesis.

Does the fetus lose weight in utero following fetal death: a study in preterm infants

Objective To evaluate whether the fetus loses weight in utero following fetal death, looking specifically at weight differences according to whether the death occurred during labour or before labour. Design Record linkage of maternity data and perinatal mortality data. Setting Scotland, UK. Population A group of 8069 singleton live and stillbirths without obvious congenital abnormalities delivered at 24–32 weeks. Main outcome measure Birthweight. Results Stillborn infants weighed less than liveborns of equivalent gestational age at delivery. Stillborn infants in whom the death occurred during labour weighed more than those in whom the death occurred before labour; this applied to both vaginal deliveries and those by caesarean section. Conclusions These findings could be attributed to the hypothesis that the low birthweight of stillborn infants is due to weight loss following the death, in addition to any process of growth restriction before the death. The analysis described here contains no data which would negate this hypothesis.

A New South Wales population-based study of stillbirths weighing 2,500 g or more.

This paper describes factors associated with singleton stillbirths weighing 2,500 g or more, born in 1987 and reported to the NSW Midwives' Data Collection (MDC), a statewide perinatal data collection system. A total of 136 singleton stillbirths in this weight range were notified to the MDC, representing one-quarter of all singleton stillbirths in NSW. MDC records on these stillbirths were linked with perinatal death registrations for 125 of the 136. The death registrations indicated that fetal death occurred during labour in 20 cases, prior to the onset of labour in 98, and at an unknown time in the remaining 7 cases. Placental complications, including haemorrhage and functional abnormalities of the placenta, were the most frequent group of conditions associated with the stillbirths, being recorded as the underlying cause of death in 42 (34%) of the 125 cases. Cord complications (such as cord compression or cord around the neck) were given as the underlying cause of death in 30 cases (24%). The death certificate diagnosis was confirmed by autopsy in only 27 of the 125 cases (22%), although autopsies may have been done on a further 45 cases (36%). An adequate explanation of the cause appeared to be lacking for many of the fetal deaths. This highlights the importance of a thorough and systematic investigation of stillbirths. A list of standard investigations to be carried out following a stillbirth is proposed.

Are there gaps in the provision of perinatal care in Greece?

The objective was to test the hypothesis that easy access to sophisticated hospitals is associated with a reduction in perinatal mortality. The study was a nationwide questionnaire survey of a birth cohort. All deliveries greater than 500g weight of singleton live births and stillbirths occurring throughout Greece during April 1983 were included. Completed questionnaires were returned for 10,953 deliveries (8% of total annual registered births in Greece), and data on 10,790 singleton births were analysed, including 127 stillbirths and 137 early neonatal deaths. The questionnaires contained information on demographic characteristics of each parent, mother's reproductive history, and clinical course of pregnancy, labour and perinatal period. Mothers living in big urban centres were compared with the rest of the country. Overall mortality rates were similar but births in the big urban centres were of significantly lower weight due to fetal growth retardation. Logistic regression analysis, taking account of birthweight, parity, maternal age, and maternal education showed that there was an advantage to mothers living in big urban centres, perinatal mortality being 63% higher in the rest of the country (chi 2 = 7.4, p less than 0.01). The evidence obtained supports the original hypothesis and suggest that a reduction in the high perinatal mortality rate in Greece may be achieved by restructuring the perinatal services.

Seasonal patterns in perinatal mortality and preterm delivery.

An investigation of possible seasonal patterns in preterm delivery and perinatal mortality utilized linked birth, infant death, and fetal death records from Minnesota for the years 1967-1973. Data included over 400,000 white singleton live births and stillbirths of 29 or more weeks completed gestation. Composite monthly cohorts of ongoing pregnancies were constructed for each month of the year and the probability of a preterm delivery and/or perinatal death was estimated. A statistically significant increase in the probability of a preterm delivery or perinatal death occurred during July, August, and September. The probability of a preterm delivery ranged from a low of 55 per 1000 pregnancies at risk in April to a high of over 59 per 1000 in July and August. In addition, although each assigned cause of death group showed a similar pattern, perinatal deaths due to infection in the mother or fetus showed a standardized mortality ratio of 65 in May and 155 in August and September, while the ratios of all other causes combined ranged from 94 to 108. Fetal deaths reported as having occurred before labor began showed a seasonal pattern nearly identical with that for all perinatal deaths, while those occurring during labor showed no seasonal pattern. The findings are consistent with published evidence that environmental factors likely involving ascending infections may play a larger role in preterm delivery and perinatal mortality than has been generally recognized.

INFLUENCE OF PREGNANCY SPACING ON OUTCOME OF PREGNANCY

To assess the significance of the length of time between two pregnancies on the outcome of the second we used information collected by the British Perinatal Mortality Survey of 1958. From questionnaires on the 16,994 singleton births in the first week of March 1958 and the 7,117 singleton stillbirths and neonatal deaths in March, April, and May 1958 we abstracted information on the date and outcome of any preceding pregnancy. The interpregnancy interval was taken as the length of time between this preceding pregnancy and the last menstrual period before the index pregnancy. The most important factors influencing pregnancy spacing were outcome of the preceding delivery, social class, and maternal age. When these variables had been taken into account we found that the length of interpregnancy interval had little effect on stillbirth rates. High neonatal death rates, however, occurred when interpregnancy intervals were less than six months (P <0.005), though longer intervals had no significant effects.

Influence of pregnancy spacing on outcome of pregnancy.

To assess the significance of the length of time between two pregnancies on the outcome of the second we used information collected by the British Perinatal Mortality Survey of 1958. From questionnaires on the 16,994 singleton births in the first week of March 1958 and the 7,117 singleton stillbirths and neonatal deaths in March, April, and May 1958 we abstracted information on the date and outcome of any preceding pregnancy. The interpregnancy interval was taken as the length of time between this preceding pregnancy and the last menstrual period before the index pregnancy. The most important factors influencing pregnancy spacing were outcome of the preceding delivery, social class, and maternal age. When these variables had been taken into account we found that the length of interpregnancy interval had little effect on stillbirth rates. High neonatal death rates, however, occurred when interpregnancy intervals were less than six months (P <0.005), though longer intervals had no significant effects.