Birthweight, preterm births and neonatal mortality in Belgium and the United States

Summary. Belgium is known to have a lesser low birthweight rate and a lower infant mortality rate than the United States. We used previously unpublished data to show that beneath this comparison lies a more complicated picture. Singleton live birth certificates for 1986-67 were analysed. Despite a lower mean birthweight in Belgium (3360 g) than in the United States (3420 g), Belgium had fewer (4.9%) low birthweight infants than the US (5.9%) because of fewer preterm births (4.4 vs. 9.3%). Consistent with the excess of preterm births in the US, the residual distribution of birthweight was smaller in Belgium (2.2% vs. 3.1%). Whereas neonatal mortality was 4.8/1000 in Belgium and 5.6/1000 in the US, birthweight-specific neonatal mortality was higher in Belgium. The challenge for Belgium is to improve the survival of newborns regardless of their birthweight. In the US, the task is to eliminate the excess of small preterm infants.     

Perinatal mortality in rural Malawi.

Reported are the results of a study to assess the prevalence and risk factors for perinatal death among pregnant women in Malawi over the period 1987-90. There were 264 perinatal deaths among the 3866 women with singleton pregnancies (perinatal mortality rate, 68.3 per 1000 births). Among the risk factors for perinatal mortality were the following: reactive syphilis serology, nulliparity, a late fetal or neonatal death in the most recent previous birth, maternal height < 150 cm, home delivery, and low socioeconomic status. Although unexplained perinatal deaths will continue to occur, perinatal mortality can be reduced if its causes and risk factors in a community are given priority in antenatal and intrapartum care programmes. The following interventions could potentially reduce the perinatal mortality in the study population: screening and treating women with reactive syphilis serology; and management from early labour, by competent personnel in a health facility, of nulliparous women and multiparous women who are short or have a history of a perinatal death.     

Syphilis-associated perinatal and infant mortality in rural Malawi.

In Mangochi District, a rural area of Malawi, the prevalence of active syphilis was 3.6% among 3591 women who had singleton births and who were negative for human immunodeficiency virus (HIV). Compared with non-syphilitic women, those with active syphilis (positive Venereal Disease Research Laboratory/rapid plasmin reagin tests (titre > or = 1:8) and a reactive microhaemagglutination assay) were more likely to experience stillbirths as well as the early and late neonatal deaths and even postneonatal deaths of their children. Characteristics associated with active syphilis were not very useful in targeting women at high risk of having the condition, which makes universal screening in antenatal programmes the most efficacious way to prevent syphilis-associated morbidity and mortality. The potential for a programme to prevent congenital syphilis in the perinatal, neonatal, and post-neonatal periods is evident. In considering resource allocation to child survival programmes in areas where the prevalence of syphilis is high, officials need to include antenatal syphilis screening, using rapid tests and treatment at the first contact of the mother with the health care system.     

Obstetrical volume and early neonatal mortality in preterm infants

Objective Regionalised perinatal care with antenatal transfer of high risk pregnancies to Level III centres is beneficial. However, levels of care are usually not linked to caseload requirements, which remain a point for discussion. We aimed to investigate the impact of annual delivery volume on early neonatal mortality among very preterm births. Methods All neonates with gestational age 24–30 weeks, born 1991–1999 in Lower Saxony were included into this population-based cohort study (n = 5,083). Large units were defined as caring for more than 1,000 deliveries/year, large NICUs as those with at least 36 annual very low birthweight (<1,500 g, VLBW) admissions. Main outcome criterion was mortality until day 7. Adjusted Odds Ratios (adj. OR) and 95% confidence intervals (CI) were calculated based on generalised estimating equation models, accounting for correlation of individuals within units. Results Within the first week of life, 20.6% of all neonates deceased; 10.2% were stillbirths, 3.7% died in the delivery unit, and 6.7% in the NICU. The crude OR for early neonatal mortality after having been delivered in a small delivery unit (excluding stillbirths) was 1.36 (95%CI 1.04–1.78; adj. OR 1.16 (0.82–1.63)). It increased to 1.96 (1.54–2.48; adj. OR 1.21 (0.86–1.70)) after the inclusion of stillbirths. Conclusion This study has shown a slight, but non-significant association between obstetrical volume and early neonatal mortality. In future studies the impact of caseload on outcome may become more evident when referring to high-risk patients instead of to the overall number of deliveries.     

Patterns and causes of neonatal and postneonatal mortality in rural Bangladesh

Community-level research data from a Maternal-Child Health and Family Planning (MCH/FP) program and comparison areas in rural Bangladesh indicate that 60 percent of infant deaths occurred in the neonatal period in both areas. Since the inception of the MCH/FP program, mortality rates declined relative to those in the comparison area. This decline, however, was confined to the neonatal period death rates only, with mortality rates in the postneonatal period remaining similar in the two areas. Prematurity accounted for approximately 40 percent of deaths in the neonatal period. Cause-of-death data indicated that the differences in the neonatal mortality rates between the two areas was mainly due to a marked decline in tetanus neonatorum deaths in the MCH/FP program area, because of the tetanus toxoid immunization of pregnant women there. The interventions in the MCH/FP area, however, did not significantly influence mortality due to any other cause. This study provides an explanation for the limited impact on infant mortality of health interventions that focus on diarrheal diseases and immunizations of children.     

Differentials in neonatal mortality in two adjacent rural areas of Bangladesh: Lessons for neonatal health interventions

Abstract

A household survey, conducted in three rural sub-districts of northeastern Bangladesh, revealed a markedly lower neonatal mortality rate (NMR) in one sub-district compared to two adjacent sub-districts. This study examines the degree to which the differential in NMR can be explained by factors that could be improved by maternal and newborn health programmes, such as knowledge of danger signs and use of antenatal, delivery, and postnatal care. Use of a skilled birth attendant in uncomplicated deliveries, mothers’ knowledge of newborn complications, and use of health care for sick newborns accounted for 32% of the differential in NMR. Pregnancy and delivery complications were associated with increased risk of neonatal mortality, and distance to nearest emergency obstetric care facility was significantly associated with lower risk of neonatal mortality. Therefore, health programmes to improve mothers’ knowledge of newborn complications, to increase access to emergency obstetric care, and to promote appropriate use of health care could significantly reduce neonatal mortality in impoverished communities.     

Seasonality of preterm births in Japan.

Seasonal variations in the proportion of preterm births in Japan from January 1979 to December 1983 are analysed using a traditional method of time-series analysis, which divides the variation in a series into trend, seasonal variation, other cyclic change, and remaining irregular fluctuations. It is shown that the proportion of preterm births in Japan have a clear seasonal periodicity with two peaks in summer and winter. Analysis of seasonality by period of gestation shows that interesting differences in kurtosis and skewness exist between summer and winter, i.e. the summer increase in preterm births was characterized by an increase of skewness which means an extension of the lower part of the distribution. On the other hand, the winter increase was characterized by a decrease of kurtosis which corresponds to a flat-topped distribution. This result suggests that causes of preterm births might be different between the two seasons. Theoretical simulations based on actual birth data in Japan over the period, are carried out to examine how season of conception could influence seasonal variations in the proportion of preterm births. Results show that, at least for first births, seasonality in conception rates could be one explanatory factor for the observed seasonal variation in proportions of preterm births. Another analysis reveals that conception in May and June are more likely to result in preterm births in Japan.     

The impact of multiple preterm births on the family

As the number of multiple births has steadily risen over the past 20 years, twins and triplets form an increasingly large proportion of the preterm population. This causes a number of stresses to their families. Addressing the cause of the epidemic of iatrogenic multiple births is the most effective way to reduce the number of preterm infants and the long-term problems to which they are prone.     

The epidemiology of perinatal mortality in multiple births.

The epidemiology of perinatal mortality in multiple pregnancies was investigated from data on 16,831 multiple births from New York City''s computerized vital records for 1978-1984. Twins had a sixfold higher rate of neonatal death and a threefold higher rate of fetal death during labor than had singleton infants. Much of this excess mortality can be explained by the lower birthweight distribution in twins: between 1,001 and 2,500 grams twins had birthweight-specific death rates equivalent to or substantially less than singletons. However, in infants of normal birthweights, twins had more than three times the mortality risk of singletons. For twins in vertex presentation between 1,001 and 3,000 grams, cesarean section did not appreciably reduce neonatal mortality risk. For twins in vertex presentation who weighted more than 3,000 grams the neonatal mortality rate was more than four times higher in vaginal deliveries than in cesarean sections (exact p = 0.034). Efforts to prevent intrapartum and neonatal mortality in multiple births should aim at reducing the incidence of low birthweight twins. More research is needed on the etiology of perinatal problems in normal birthweight twins (greater than or equal to 2,501 grams), especially on the effects of different modes of delivery.     

Maternal age and preterm births in a black population

Babies born to teenagers aged 15-19 years have a substantial risk of dying within the first year of life. Although associated socio-demographic factors may account for an increase in the risk of adverse reproductive outcomes for teenagers, there is a concern that young maternal age may also be a biological risk factor. We examined the effects of maternal age of primiparous black women on the incidence of preterm births using data from 6,072 black women delivering between 1989 and 1995 at an urban perinatal network of 17 hospitals and health centres serving residents in a well-defined geographical area. Maternal age was grouped as: < or = 15, 16-17, 18-19, 20-24, 25-29 or > or = 30 years age groups. The 20-24 age group with the highest number of births and lowest preterm rate was used as the reference age. Preterm birth was defined as delivery < 37 completed weeks of gestation. Of the 6,072 infants born to the cohort, 1,170 (19.3%) were preterm. The unadjusted odds for a preterm birth for the < or = 15-year-olds (odds ratio [OR] = 0.97; 95% confidence interval [CI], 0.69,1.36), for the 16- to 17-year-olds (OR=1.21; CI=0.94, 1.57) and for the 18- to 19-year olds (OR=1.15, CI = 0.92, 1.43) were not significantly different from that for the reference group. The risk for the 25-to 29-year-old mothers was 1.26 times [CI = 1.05, 1.50] and for the > 30-year-old mothers 1.28 times [CI = 1.07, 1.52] that for the reference group. Adjustments using logistic regression analysis for the effects of maternal smoking, drug abuse during pregnancy, insurance status, having prenatal care and median family income from census tract of residence did not result in a significantly increased risk for preterm birth or low birthweight for the teenage groups compared with the reference group. We conclude that primiparous teenage black mothers do not have an inherent biologically increased risk for preterm births.     

Racial disparities in preterm births. The role of urogenital infections.

OBJECTIVES: To evaluate the impact of urogenital infections on the racial gap between black and white women in preterm birth rates. METHODS: A computer-assisted search of the medical literature was conducted through MEDLINE aided by a manual bibliographic search of published articles and relevant books. Estimates of the relative risk for preterm birth were extracted from published studies for the following infections: N. gonorrhea, syphilis, trichomoniasis, Chlamydia trachomatis, Group B streptococcal vaginal colonization, asymptomatic bacteriuria, genital mycoplasmas, and bacterial vaginosis. Estimates of the prevalence among black and white women by race for each of these infections were extracted from published studies. The attributable risk for preterm birth for selected infections was then calculated for the black and white populations and the impact on the racial gap in preterm births was estimated. RESULTS: Only bacterial vaginosis and bacteriuria appear to be established risk factors for preterm births. Significantly higher rates of bacterial vaginosis among black women may account for nearly 30% of the racial gap in preterm births. Higher rates of bacteriuria among black women may account for roughly 5% of the gap. CONCLUSION: Although these findings are limited by the reliability of published estimates of prevalence and relative risk for these infections, treatment of infections during pregnancy, particularly bacterial vaginosis, offers hope for reducing the racial gap in preterm births.     

Lower mortality but higher neonatal morbidity over a decade in very preterm infants

Better perinatal care has led to better survival of very preterm children, but may or may not have increased the number of children with cerebral and pulmonary morbidity. We therefore investigated the relationship between changes in perinatal care during one decade, and short-term outcome in very preterm infants. Perinatal risk factors and their effects on 28-day and in-hospital mortality, and on intraventricular haemorrhage and bronchopulmonary dysplasia (BPD) in survivors, were compared in two surveys of very preterm singleton infants in the Netherlands. Between 1983 and 1993, 28-day mortality decreased from 52.1% to 31.8% in infants of 25-27 weeks' gestation and from 15.2% to 11.3% in infants of 28-31 weeks' gestation. The incidence of intraventricular haemorrhage in survivors did not change (44.4% and 43.3% in infants of 25-27 weeks' gestation, and 29.0% and 24.0% in infants of 28-31 weeks' gestation). The incidence of BPD in survivors increased from 40.3% to 60.0% in infants of 25-27 weeks' gestation and remained similar in infants of 28-31 weeks' gestation (8.5% and 9.8% respectively). In multivariable analysis, higher mortality was associated with congenital malformation, low gestational age, low birthweight, no administration of steroids before birth, low Apgar scores and intraventricular haemorrhage, in 1983 as well in 1993, and with male gender in 1993. The effect of maternal age on mortality diminished significantly between 1983 and 1993. Intraventricular haemorrhage in surviving children was associated with low gestational age and artificial ventilation, both in 1983 and in 1993. The effect of artificial ventilation on the incidence of intraventricular haemorrhage diminished significantly between 1983 and 1993. BPD was associated with low gestational age and artificial ventilation, both in 1983 and in 1993, and with low birthweight and caesarean section in 1993. We conclude that the better survival of very preterm infants, especially of those of 25-27 weeks' gestation, has been accompanied by a similar incidence (and thus with an increased absolute number) of children with intraventricular haemorrhage and by an increased incidence of children with BPD.     

Validating neonatal mortality and use of NGO reproductive health outreach services in rural Bangladesh

Although the neonatal mortality rate (NMR) in Bangladesh remained steady between 1995-99 and 1999-2003 (41-42 deaths per 1,000 live births), evidence from the management information system (MIS) of a large nongovernmental organization (NGO) program indicates that the NMR declined by about 50 percent between 1996 and 2002 in the area served. This study aims to validate the recording of neonatal deaths among the cohort of children registered as born in 2003 and to assess the evidence of a decline in the NMR. It also measures the coverage of reproductive health outreach services, focusing on 12 of the 27 NGOs that have provided services in the same areas since 1996. Field-workers' registers, verbal autopsy reports, and immunization records were checked to confirm infants' survival. Interviews were conducted with 142 mothers of children who died within 28 days postpartum and with a random sample of 109 women with registered stillbirths. Out of 11,253 registered live births in 2003, 210 neonatal deaths were found, compared with 194 deaths that were reported in the MIS for 2003. The corrected NMR was 19 deaths per 1,000 live births, and it was in the range of 15-29 deaths per 1,000 live births in 11 of the NGO areas. Because underreporting of neonatal deaths was probably higher in 1996 when the MIS-reported NMR was 39 deaths per 1,000 live births, the decline in the NMR is likely to have been genuine.     

The associations of birth intervals with small-for-gestational-age,preterm, and neonatal and infant mortality: a meta-analysis

Background

Short and long birth intervals have previously been linked to adverse neonatal outcomes. However, much of the existing literature uses cross-sectional studies, from which deriving causal inference is complex. We examine the association between short/long birth intervals and adverse neonatal outcomes by calculating and meta-analyzing associations using original data from cohort studies conducted in low-and middle-income countries (LMIC).

Methods

We identified five cohort studies. Adjusted odds ratios (aOR) were calculated for each study, with birth interval as the exposure and small-for-gestational-age (SGA) and/or preterm birth, and neonatal and infant mortality as outcomes. The associations were controlled for potential confounders and meta-analyzed.

Results

Birth interval of shorter than 18 months had statistically significant increased odds of SGA (pooled aOR: 1.51, 95% CI: 1.31-1.75), preterm (pooled aOR: 1.58, 95% CI: 1.19-2.10) and infant mortality (pooled aOR: 1.83, 95% CI: 1.19-2.81) after controlling for potential confounding factors (reference 36-<60 months). It was also significantly associated with term-SGA, preterm-appropriate-for-gestational-age, and preterm-SGA. Birth interval over 60 months had increased risk of SGA (pooled aOR: 1.22, 95% CI: 1.07-1.39) and term-SGA (pooled aOR: 1.14, 95% CI: 1.03-1.27), but was not associated with other outcomes.

Conclusions

Birth intervals shorter than 18 months are significantly associated with SGA, preterm birth and death in the first year of life. Lack of access to family planning interventions thus contributes to the burden of adverse birth outcomes and infant mortality in LMICs. Programs and policies must assess ways to provide equitable access to reproductive health interventions to mothers before or soon after delivering a child, but also address underlying socioeconomic factors that may modify and worsen the effect of short intervals.

     

HIV infection and fertility preferences in rural Malawi

Although HIV-prevalence and fertility rates in sub-Saharan Africa are among the highest in the world, little is known about how HIV infection affects the fertility preferences of men and women in the region. A quasi-experimental design and in-depth interviews conducted in rural Malawi are employed to examine how and through what pathways learning that one is HIV positive alters a person's childbearing desires. Among rural Malawians, particularly men, the desire to have more children decreases after receiving a positive HIV-test result. The motivations underlying this effect are greatly influenced by gender: women fear the physical health consequences of HIV-positive pregnancies and childbearing, whereas men see childbearing as futile because they anticipate their own early death and the deaths of their future children. Considerable ambivalence remains, nevertheless, particularly among women who strategize to live normal lives in spite of their infection, but whose definitions of "normal" vary.     

Childhood malnutrition and its predictors in rural Malawi

We prospectively followed up a population-based cohort of 767 rural Malawian children from birth to 36 months to characterise the timing and predictors of malnutrition. Underweight and wasting incidence peaked between 6 and 18 months of age, whereas stunting incidence was highest during the first 6 months of age. After infancy about 40% of the children were underweight, 70% stunted, and about 4% wasted. Small size during the first 3 months of life predicted the incidence of severe underweight (relative risk [95% confidence interval], 1.8 [0.9, 3.4]), severe stunting ( 2.1 [1.3, 3.4]), and moderate wasting (2.0 [1.1, 3.5]). Children with many illness episodes in infancy had a twofold risk for the development of severe underweight and moderate wasting. Severe underweight was further predicted by residence far away from a health facility and moderate wasting by maternal HIV infection. Our conclusion is that the intrauterine period and first 6 months of life are critical for the development of stunting whereas the subsequent year is more critical for the development of underweight and wasting. Strategies combating intrauterine growth retardation, maternal HIV and infant morbidity are likely to reduce the burden of malnutrition in this population.     

Seasonal variation of births in rural southwestern Nigeria

A total of 12 708 live births registered between 1965 and 1975 in Igbo Ora, a rural area in southwestern Nigeria, were examined for seasonal variation using trigonometric regression analysis. The monthly number of registered births showed a significant seasonal pattern with a peak in May and corresponding minima in November. The extent of the seasonal variation above and below the annual mean was about 7%. There has been no significant shift in both the month of peak occurrence and the magnitude of the variation within the 11-year period of study. It is thought that the observed seasonal pattern may be related to climatic factors as well as sociocultural patterns of life associated with cyclical farming activities characteristic of a predominantly agricultural community.