Perinatal mortality and sex ratios in Hawaii

Retrospective data obtained from a sample of 926 mothers of European ancestry (AEA) and 368 mothers of Japanese ancestry (AJA) living in Hawaii were used to evaluate two hypotheses, the selective male affliction hypothesis and the Trivers-Willard female condition hypothesis, for male-biased perinatal mortality and altered sex ratio at birth. Logit analyses using pregnancy outcome (live-birth versus stillbirth or miscarriage) as the dependent variable and either sex of prior sib, sex of offspring, parity, age of mother, or interval since last pregnacy as independent variables did not support either hypothesis. In contrast to the prediction of the selective male affliction model, sex of previous pregnancy was not related to perinatal mortality. Although each of the other independent variables exerted significant effects on perinatal mortality and, therefore, presumably affected female condition, in no case did natal sex ratios become female-biased. The Trivers-Willard hypothesis predicts that female-biased sex ratios are expected when female condition is reduced. The results are discussed in relation to the possibility that degree of sexual dimorphism may favor male-biased perinatal mortality and explains the observed decline in sex ratio with parity.     

Maternal smoking in pregnancy and sex differences in perinatal death between boys and girls

Abstract

The sex difference in perinatal mortality in developed countries is largely unexplained. The current study evaluated the differences in the impact of maternal smoking during pregnancy on the risk of perinatal death between males and females. The analysis involved 11,469 and 9,404 newborns derived from two population‐based birth cohorts in Northern Finland, for 1966 and 1985–86, respectively. The perinatal mortality rate was 23 per thousand in the 1966 cohort and 9 per thousand in the 1985–86 cohort. The rate ratio (RR) for mortality for males over females is 1.15 and 1.60 in the two cohorts, respectively. Among children whose mothers smoked during pregnancy, the RR was 2.2 (95% CI 1.0, 4.7) for the former cohort and 4.8 (95% CI 1.5, 15.2) for the later cohort; and among the children whose mothers did not smoke the corresponding RR was 1.2 (95% CI 0.9, 1.6) and 1.1 (95% CI 0.6, 1.9). Maternal smoking during pregnancy could be an important determinant accounting for the excess perinatal death for males over females. Our results encourage evaluation of the findings among other populations.     

Perinatal mortality by birth order within cohorts based on sibship size.

Cross-sectional surveys of perinatal mortality show a U-shaped curve when plotted against parity, implying that fourth and subsequent babies are at increased risk. Our study of a large, population-based longitudinal data set shows that this result is an artefact and that perinatal mortality falls with increasing parity. Within cohorts of mothers based on attained sibship size the perinatal mortality decreases with increasing parity and increases with sibship size. These associations, which are not noticeably affected by maternal age, ssem in part to operate through an association between parity, sibship size, and birth weight. This analysis shows the importance of using longitudinal data in analysing such relations.     

Influence of maternal age, parity and social class on perinatal mortality in Scotland: 1960-82

This study examines secular changes in the influence of maternal age, parity and social class on perinatal mortality in Scotland. Using cross-sectional national data on all Scottish legitimate births the effects of these factors are estimated on the risk of stillbirths, neonatal and perinatal deaths, and the extent to which the current pattern of relative risks in the early 1980s has changed over the past 2 decades is investigated. Social class is used as a crude measure of relative as opposed to absolute differences in socioeconomic conditions which may influence reproductive outcomes. The effects of age, parity and social class are estimated using logistic models. The most parsimonious model adequately describing the data is provided by a main effects model without interactions. Despite changes in reproductive behavior, improved access to maternity services and more effective perinatal care, the influence of maternal age and social class on perinatal mortality remained unchanged between 1960 and 1982. Although the absolute risks of stillbirths and neonatal deaths declined in all maternal age groups, this improvement was not accompained by a significant change in the relative risks traditionally associated with age. Despite no significant changes in the traditional J-shaped association between parity and stillbirths, cross-sectional analysis shows that in the early 1980s the risk of both neonatal and perinatal deaths decreased as parity increased. This finding is consistent with the pattern of risks observed in longitudinal studies and retrospective surveys of reproductive histories. In view of the stability of age, parity and social class effects on the risk of perinatal mortality, little if any of the overall decrease in Scottish stillbirth and neonatal death rates can be attributed to a significant narrowing of relative risks. The results suggest that the attributable risk of high maternal age or low social class on perinatal mortality is negligible. Future improvements in perinatal mortality are thus likely to result from a continuation of the uniform decrease in perinatal mortality for women of all ages, parities and social classes and not from a diminishing of differences in relative risks which are now virtually identical for a large and growing % of women in Scotland.     

Contraceptive practices and fertility among Southeast Asian,black, and white mothers attending a maternal infant care program

Abstract

The purpose of this analysis was to determine if there were differences in selected fertility characteristics including parity, pregnancy spacing, age at first pregnancy, age of menarche, breastfeeding postpartum, and contraceptive practices among white, black, Hmong, and other Southeast Asian mothers attending a maternal infant care program in Minneapolis, Minnesota, during 1980–82.

White and black mothers were younger than the Hmong and other Asian mothers. The lowest mean age of first pregnancy was among blacks. Ages of first pregnancy were similar for whites, Hmong, and other Asians, although the mean age of menarche was approximately two years later for Hmong and other Southeast Asian mothers compared to the white and black mothers.

Based on self reports at the first postpartum visit one month after delivery, 39 per cent of the whites and 25 per cent of the blacks were breastfeeding. In comparison 8.7 per cent of the Hmong and 17 per cent of the other southeast Asian mothers were breastfeeding.

Maternal age and age at first pregnancy were significant predictors of parity for whites, blacks, Hmong, and the other Southeast Asians. Ever‐use of contraception was a significant predictor of parity only for Hmong.

The highest proportion of ever‐users of contraception was among the white mothers (80 per cent) followed by the blacks (69.3 per cent) and other Asian mothers (34.8 per cent). Hmong mothers had the lowest proportion having used contraception (17.1 per cent).     

Analysis of ethnic differences in perinatal statistics.

The 3996 mothers delivered at Dudley Road Hospital, Birmingham, in 1979 were analysed for their ethnic origins. Social classes IV and V predominated in all groups. A high proportion of Indian mothers fell into the low-risk group based on age and parity but had the highest stillbirth and perinatal mortality rates (15.1 and 27.5/1000 respectively) and infants of low mean birth weight (2986 g). Elderly and multiparous mothers were characteristic of the Pakistani and Bangladeshi groups. Young, primiparous mothers were more common among the West Indians and Europeans, in whom the stillbirth and perinatal mortality rates were low; infants in the European group had a mean birth weight higher than in any other group (3231 g). From these findings ethnic origin of the mother is apparently an important factor in perinatal mortality.     

PTC tasting and group membership

Abstract

Child mortality experience may affect subsequent fertility of couples by exerting the so‐called “physiological” and/or “replacement” responses. The influence of either effect should become apparent upon an examination of individual reproductive histories. The impact of infant and early childhood mortality on subsequent reproductive behavior of couples is analyzed for the presence and intensity of these effects. Historical data are derived from 1,261 families in two communities in western Massachusetts. Relationships of intervals between successive confinements, and parity progression ratios, according to the fate of previous births, are examined. While forms of family limitation have been employed by the study population, indicating that the capacity for replacement existed, the data do not reveal any significant attempt at child replacement.     

Programming social behavior by the maternal fragile X protein

The developing fetus and neonate are highly sensitive to maternal environment. Besides the well‐documented effects of maternal stress, nutrition and infections, maternal mutations, by altering the fetal, perinatal and/or early postnatal environment, can impact the behavior of genetically normal offspring. Mutation/premutation in the X‐linked FMR1 (encoding the translational regulator FMRP) in females, although primarily responsible for causing fragile X syndrome (FXS) in their children, may also elicit such maternal effects. We showed that a deficit in maternal FMRP in mice results in hyperactivity in the genetically normal offspring. To test if maternal FMRP has a broader intergenerational effect, we measured social behavior, a core dimension of neurodevelopmental disorders, in offspring of FMRP‐deficient dams. We found that male offspring of Fmr1^+/? mothers, independent of their own Fmr1 genotype, exhibit increased approach and reduced avoidance toward conspecific strangers, reminiscent of ‘indiscriminate friendliness’ or the lack of stranger anxiety, diagnosed in neglected children and in patients with Asperger's and Williams syndrome. Furthermore, social interaction failed to activate mesolimbic/amygdala regions, encoding social aversion, in these mice, providing a neurobiological basis for the behavioral abnormality. This work identifies a novel role for FMRP that extends its function beyond the well‐established genetic function into intergenerational non‐genetic inheritance/programming of social behavior and the corresponding neuronal circuit. As FXS premutation and some psychiatric conditions that can be associated with reduced FMRP expression are more prevalent in mothers than full FMR1 mutation, our findings potentially broaden the significance of FMRP‐dependent programming of social behavior beyond the FXS population.     

Quality of obstetric care provided for Asian immigrants in Leicestershire.

Between 1976 and 1981 some 939 perinatal deaths occurred to women living in Leicestershire, of which 128 (14%) were to Asian women. The qualifications of the general practitioners, the gestation at which women start antenatal care, and perinatal death were used as structural, process, and outcome measures for evaluating the services provided to Asian immigrants within this population. Perinatal deaths were divided into four groups: congenital malformation, macerated stillbirth, asphyxia in labour, and immaturity. Asian mothers had one and a half times the risk of perinatal mortality when social class, parity, height, legitimacy, and the general practitioner''s qualifications were taken into account. Asian and non-Asian mothers with general practitioners who were not on the obstetric list had more than twice the risk of a perinatal death when a similar adjustment was made. Recommendations include priority allocation of community midwives to practitioners not on the obstetric list, the establishment of postgraduate courses for such doctors, and the continued evaluation of the effect of such proposals on perinatal mortality.     

Seasonal dynamics of Anopheles species at three locations in the Republic of Korea

Weekly changes in adult Anopheles species were monitored at Camp Humphreys (CH), Ganghwa Island (GH), and Warrior Base (WB), from May‐October, 2009–2010 to explore the relationship between Plasmodium vivax development and vector dynamics in the Republic of Korea (ROK). Adult females were trapped and dissected to determine parity for estimating longevity, mortality, and birthrate. A degree‐day (DD) method was used to estimate the extrinsic incubation period (EIP) of P. vivax and duration of the gonotrophic cycle and other life stages. Anopheles sinensis was the predominant species, with satellite data showing peak abundance occurring after the period of maximum greenness. Abundance peaks were location dependent, comprised nulliparous and parous females, and timing could not be fully explained by DD estimation. Parity showed synchronicity between locations and years and was highest for September and lowest during maximum greenness. Mosquito longevity was predicted to exceed the EIP (when malaria transmission is possible) during weeks 29, 31, 34, and near the end of the season. Area‐wide changes in parity suggest a common cause; information on local larval habitat and agricultural practices may explain location‐specific effects. DD estimates of EIP and parity could be used to predict when conditions are suitable for P. vivax transmission.     

Caesarean Section Frequency among Immigrants,Second- and Third-Generation Women,and Non-Immigrants: Prospective Study in Berlin/Germany

ObjectiveThe frequency of caesarean section delivery varies between countries and social groups. Among other factors, it is determined by the quality of obstetrics care. Rates of elective (planned) and emergency (in-labor) caesareans may also vary between immigrants (first generation), their offspring (second- and third-generation women), and non-immigrants because of access and language barriers. Other important points to be considered are whether caesarean section indications and the neonatal outcomes differ in babies delivered by caesarean between immigrants, their offspring, and non-immigrants.MethodsA standardized interview on admission to delivery wards at three Berlin obstetric hospitals was performed in a 12-month period in 2011/2012. Questions on socio-demographic and care aspects and on migration (immigrated herself vs. second- and third-generation women vs. non-immigrant) and acculturation status were included. Data was linked with information from the expectant mothers’ antenatal records and with perinatal data routinely documented in the hospital. Regression modeling was used to adjust for age, parity and socio-economic status.ResultsThe caesarean section rates for immigrants, second- and third-generation women, and non-immigrant women were similar. Neither indications for caesarean section delivery nor neonatal outcomes showed statistically significant differences. The only difference found was a somewhat higher rate of crash caesarean sections per 100 births among first generation immigrants compared to non-immigrants.ConclusionUnlike earlier German studies and current studies from other European countries, this study did not find an increased rate of caesarean sections among immigrants, as well as second- and third-generation women, with the possible exception of a small high-risk group. This indicates an equally high quality of perinatal care for women with and without a migration history.     

Non-target impacts of poison baiting for predator control in Australia

• 1 Mammalian predators are controlled by poison baiting in many parts of the world, often to alleviate their impacts on agriculture or the environment. Although predator control can have substantial benefits, the poisons used may also be potentially harmful to other wildlife.
• 2 Impacts on non‐target species must be minimized, but can be difficult to predict or quantify. Species and individuals vary in their sensitivity to toxins and their propensity to consume poison baits, while populations vary in their resilience. Wildlife populations can accrue benefits from predator control, which outweigh the occasional deaths of non‐target animals. We review recent advances in Australia, providing a framework for assessing non‐target effects of poisoning operations and for developing techniques to minimize such effects. We also emphasize that weak or circumstantial evidence of non‐target effects can be misleading.
• 3 Weak evidence that poison baiting presents a potential risk to non‐target species comes from measuring the sensitivity of species to the toxin in the laboratory. More convincing evidence may be obtained by quantifying susceptibility in the field. This requires detailed information on the propensity of animals to locate and consume poison baits, as well as the likelihood of mortality if baits are consumed. Still stronger evidence may be obtained if predator baiting causes non‐target mortality in the field (with toxin detected by post‐mortem examination). Conclusive proof of a negative impact on populations of non‐target species can be obtained only if any observed non‐target mortality is followed by sustained reductions in population density.
• 4 Such proof is difficult to obtain and the possibility of a population‐level impact cannot be reliably confirmed or dismissed without rigorous trials. In the absence of conclusive evidence, wildlife managers should adopt a precautionary approach which seeks to minimize potential risk to non‐target individuals, while clarifying population‐level effects through continued research.

     

Early sexual maturity among Pumé foragers of Venezuela: fitness implications of teen motherhood

Because humans have slow life histories, discussions of the optimal age at first birth have stressed the benefits of delayed reproduction. However, given the diversity of ecological, fertility, and mortality environments in which humans live, reproductive maturity is expected to be highly variable. This article uses reproductive histories to examine a pattern of early menarche and first birth among the Pume, a group of South American foragers. Age at menarche and first birth are constructed using both retrospective and cross‐sectional data for females over the age of 10 (n = 83). The objectives are first to define these patterns and then discuss their reproductive consequences. On average, Pume girls reach menarche at age 12.9, and give birth to their first child at age 15.3–15.5 (retrospective and cross‐sectional data, respectively). This populational average falls several years prior to what often is considered the human norm. Two questions are then considered. What are the infant mortality costs across a mother's reproductive career? How does surviving fertility vary with age at first birth? Results indicate that the youngest of first‐time mothers (<14) are four times more likely to loose their firstborns than older first‐time mothers (≥17). Given parity‐specific mortality rates, the optimal strategy to minimize infant mortality and maximize reproductive span is to initiate childbearing in the midteens. Women gain no additional advantage in surviving fertility by delaying childbearing until their late teens. Am J Phys Anthropol, 2008. © 2008 Wiley‐Liss, Inc.     

Risk Factors and Adverse Perinatal Outcomes among Term and Preterm Infants Born Small-for-Gestational-Age: Secondary Analyses of the WHO Multi-Country Survey on Maternal and Newborn Health

Background

Small for gestational age (SGA) is not only a major indicator of perinatal mortality and morbidity, but also the morbidity risks in later in life. We aim to estimate the association between the birth of SGA infants and the risk factors and adverse perinatal outcomes among twenty-nine countries in Africa, Latin America, the Middle East and Asia in 359 health facilities in 2010–11.

Methods

We analysed facility-based, cross-sectional data from the WHO Multi-country Survey on Maternal and Newborn Health. We constructed multilevel logistic regression models with random effects for facilities and countries to estimate the risk factors for SGA infants using country-specific birthweight reference standards in preterm and term delivery, and SGA’s association with adverse perinatal outcomes. We compared the risks and adverse perinatal outcomes with appropriate for gestational age (AGA) infants categorized by preterm and term delivery.

Results

A total of 295,829 singleton infants delivered were analysed. The overall prevalence of SGA was highest in Cambodia (18.8%), Nepal (17.9%), the Occupied Palestinian Territory (16.1%), and Japan (16.0%), while the lowest was observed in Afghanistan (4.8%), Uganda (6.6%) and Thailand (9.7%). The risk of preterm SGA infants was significantly higher among nulliparous mothers and mothers with chronic hypertension and preeclampsia/eclampsia (aOR: 2.89; 95% CI: 2.55–3.28) compared with AGA infants. Higher risks of term SGA were observed among sociodemographic factors and women with preeclampsia/eclampsia, anaemia and other medical conditions. Multiparity (> = 3) (AOR: 0.88; 95% CI: 0.83–0.92) was a protective factor for term SGA. The risk of perinatal mortality was significantly higher in preterm SGA deliveries in low to high HDI countries.

Conclusion

Preterm SGA is associated with medical conditions related to preeclampsia, but not with sociodemographic status. Term SGA is associated with sociodemographic status and various medical conditions.     

Mortality decline in Latin America: Changes in the structure of causes of deaths, 1950–1975

Abstract

In this paper we study some of the characteristics of the process of mortality decline in Latin America during the years 1955 and 1973. This is done by analyzing the levels of overall mortality and cause‐specific mortality and their changes in the period indicated, and by examining the relation between levels of mortality and their changes and a set of endogenous variables measuring socio‐economic conditions. This analysis is intended to measure in a somewhat crude manner the effects of diffusion of medical technology vis à vis the effects of changes in socioeconomic conditions.     

Determinants of the sex ratio at birth: review of recent literature

The fact that more boys are born than girls (104-107 boys for every 100 girls) has been known since 1662. Factors determining the sex ratio at birth rate are of 2 kinds: factors determining the primary sex ratio, i.e., sex ratio at conception, and factors determining the survival of the embryo in utero. Y-bearing and X-bearing sperm may have different motility or different survival time. The age of the ovum at fertilization and the chemical balance of the female genital tract have an effect on sex ratio at conception. High levels of circulating gonadotropins may imply a lower sex ratio at birth as well as a higher rate of dizygotic twinning. Male conception also appears to be higher early and late in the menstrual cycle. The fact that women exposed to higher coital rates conceive earlier in the menstrual cycle may account for the greater number of boys born during wars. Prenatal male mortality is reportedly highest between gestational months 3-5, lower between months 6-8, and higher again st term. Also, immunological interaction between mother and embryo may account for some sex selective spontaneous abortions. 3 sociodemographic determinants of sex ratio at birth are thought to be maternal age, paternal age, and birth order. Higher prenatal male mortality may be correlated with socioeconomic conditions, since higher socioeconomic status lowers prenatal mortality in general. The effects of parental age, birth order, and parity are less clear. Race is also a factor, since the sex ratio at birth for blacks is lower (102-104) than for whites (106). 14 univariate and 19 multivariate studies of effects of maternal age, paternal age, parity, birth order, race, and socioeconomic status on sex ratio at birth, with sample sizes in the millions from various countries have been analyzed. More boys are born to younger parents, and lower order births have a higher proportion of males than do higher order births. In the multivariate analyses, when the effects of paternal and and birth order are controlled for, the effect of maternal age weakens, and the effect of paternal age appears to be stronger. The effect of birth order remains but is very small, and the effect of race persists independent of any effect of other variables. Maternal age, parity, and birth order are positively correlated with proportion of male stillbirths. The results of the multivariate analyses show all of the effects to be very small, but that maternal age has no effect on sex ratio at birth; paternal age and birth order have a negative effect, and the racial effect persists independent of any other effect. The racial effect is clearly biologically determined at conception because blacks have higher levels of circulating gonadotropin and therefore a higher probability of conceiving girls. Parents in higher socioeconomic classes are more likely to have sons, but the effect is largely due to the excess male mortality during most of the gestational period.     

Successful behavioral strategy to unite mother and infant rhesus monkeys (Macaca mulatta) after cesarean delivery

Developmental studies of pre‐ to postnatal continuities in rhesus monkeys sometimes require infants be reared with their mothers. However, complications during pregnancy or experimental designs may require cesarean delivery. Owing to lack of published information on this subject, strategies are needed to introduce mothers to their infants following cesarean delivery. Using positive and negative reinforcement techniques we attempted to unite six infant rhesus macaques, Macaca mulatta, to their mothers following c‐sections. For our seventh subject, we attempted to cross‐foster an infant onto an unrelated female after she had undergone a cesarean surgery for a late‐term spontaneous abortion. The mothers varied in age, parity, previous postnatal mothering experience with infants, housing earlier to delivery, and housing subsequent to introduction. Although there were large individual differences among the mother–infant pairs, all seven introductions were successful. The mothers learned to accept and care for their infants from the continuous application of operant conditioning techniques. These data suggest that mother‐rearing following cesarean section is a realistic possibility whether required for clinical reasons or for proper experimental control. Furthermore, the ability to successfully mother‐rear infants produced from cesarean delivery lessens the impact this potential confound of not being reared by their mothers exerts on many types of developmental studies. Am. J. Primatol. 71:510–522, 2009. © 2009 Wiley‐Liss, Inc.     

Role of maternal 5‐HT1A receptor in programming offspring emotional and physical development

Serotonin_1A receptor (5‐HT_1AR) deficiency has been associated with anxiety and depression and mice with genetic receptor inactivation exhibit heightened anxiety. We have reported that 5‐HT_1AR is not only a genetic but also a maternal ‘environmental’ factor in the development of anxiety in Swiss‐Webster mice. Here, we tested whether the emergence of maternal genotype‐dependent adult anxiety is preceded by early behavioral abnormalities or whether it is manifested following a normal emotional development. Pups born to null or heterozygote mothers had significantly reduced ultrasonic vocalization (USV) between postnatal day (P) 4 and 12, indicating an influence of the maternal genotype. The offspring's own genotype had an effect limited to P4. Furthermore, we observed reduced weight gain in the null offspring of null but not heterozygote mothers, indicating that a complete maternal receptor deficiency compromises physical development of the offspring. Except a short perinatal deficit during the dark period, heterozygote females displayed normal maternal behavior, which, with the early appearance of USV deficit, suggests a role for 5‐HT_1AR during pre‐/perinatal development. Consistent with this notion, adult anxiety in the offspring is determined during the pre‐/perinatal period. In contrast to heterozygote females, null mothers exhibited impaired pup retrieval and nest building that may explain the reduced weight gain of their offspring. Taken together, our data indicate an important role for the maternal 5‐HT_1AR in regulating emotional and physical development of their offspring. Because reduced receptor binding has been reported in depression, including postpartum depression, reduced 5‐HT_1AR function in mothers may influence the emotional development of their offspring.     

Perinatal mortality and morbidity among babies delivered in water: surveillance study and postal survey

AimTo compare perinatal morbidity and mortality for babies delivered in water with rates for babies delivered conventionally (not in water).DesignSurveillance study (of all consultant paediatricians) and postal survey (of all NHS maternity units).SettingBritish Isles (surveillance study); England and Wales (postal survey).SubjectsBabies born in the British Isles between April 1994 and March 1996 who died perinatally or were admitted for special care within 48 hours of birth after delivery in water or after labour in water followed by conventional delivery (surveillance study); babies delivered in water in England and Wales in the same period (postal survey).Results4032 deliveries (0.6% of all deliveries) in England and Wales occurred in water. Perinatal mortality was 1.2/1000 (95% confidence interval 0.4 to 2.9) live births; 8.4/1000 (5.8 to 11.8) live births were admitted for special care. No deaths were directly attributable to delivery in water, but 2 admissions were for water aspiration. UK reports of mortality and special care admission rates for babies of women considered to be at low risk of complications during delivery who delivered conventionally ranged from 0.8/1000 (0.2 to 4.2) to 4.6/1000 (0.1 to 25) live births and from 9.2 (1.1 to 33) to 64/1000 (58 to 70) live births respectively. Compared with regional data for low risk, spontaneous, normal vaginal deliveries at term, the relative risk for perinatal mortality associated with delivery in water was 0.9 (99% confidence interval 0.2 to 3.6).ConclusionsPerinatal mortality is not substantially higher among babies delivered in water than among those born to low risk women who delivered conventionally. The data are compatible with a small increase or decrease in perinatal mortality for babies delivered in water.

Key messages

• Data on adverse effects of delivery in water have been limited
• Perinatal mortality and risk of admission for special care is similar for babies delivered in water and for low risk deliveries that do not take place in water
• The risk of perinatal mortality for babies delivered in water is similar to the risk for babies born by normal vaginal delivery to women at low risk of adverse outcome
• Delivery in water may have caused water aspiration in two babies and contributed to snapped umbilical cord in five