Pregnancy outcome for nomadic Turkana pastoralists of Kenya

The outcome of an individual pregnancy is a key component of overall reproductive success and is strongly influenced by environmental, behavioral, and biological variation within populations. This prospective study examined the outcomes of 68 pregnancies among nomadic Turkana of Kenya from July 1993 to July 1994. A total of 12 women experienced pregnancy losses, and 3 women experienced live births with a subsequent perinatal death. The following characteristics are associated with increased risk for experiencing a fetal or perinatal death: severe morbidity episodes, shorter nonpregnant intervals, lower third-trimester weight, higher third-trimester summed skinfolds but limited third-trimester reduction in summed skinfolds, and higher activity levels late in gestation. Turkana newborns measured within 48 hr of birth (n = 19) weighed an average of 2,860 +/- 640 g and had a mean ponderal index of 2.72 +/- 0.46. Variation in birth weight was predicted by preterm delivery, delivery during the wet season, and maternal morbidity levels. Birth length averaged 50.8 +/- 6.8 cm and was positively influenced by full term delivery, better maternal health, and birth during the dry season. These results suggest complicated pathways linking the physical environment, subsistence requirements, heterogeneity in maternal fitness, behavior, and pregnancy outcome. The results augment the larger picture of reproductive success for Turkana nomads who live in a highly variable savanna environment.     

Premarital childbearing in northwest Kenya: challenging the concept of illegitimacy

A number of African countries, including Kenya, have experienced a marked rise in births among unmarried women. In Western countries, reproduction outside of marriage is assumed to be illegitimate and a social problem. One hypothesis used to explain the increasing incidence of premarital fertility in Africa is a breakdown of traditional social controls by the extended family over the sexual behavior of adolescents. A competing hypothesis suggests that unmarried women use sexual relations to achieve goals such as marriage. Among Turkana pastoralists of northwest Kenya, we find a pattern of premarital birth that fits either hypothesis only loosely. Premarital fertility among the Turkana is both widespread and culturally acceptable, with over 30 per cent of women having at least one child prior to marriage. Although women with premarital births initiate childbearing on average one year earlier than women with only marital births, women's marital status does not influence the length of the interval between first and second births. Marriage among the Turkana is not a social trigger for the onset and continuation of reproduction or a means to legitimate reproduction. Marital status of the parents simply determines the custody of a child. In a premarital birth, the father pays a set fee to the mother's family, and the custody of the child remains permanently with the mother's family. If the parents later marry, the father must purchase custody of the child by another fee at that time. Since the Turkana have experienced few effects of modernization, the existence of such a practice suggests that cultural factors must be taken into account before assessing premarital fertility in Africa as a social problem.     

Rates of nausea and vomiting in pregnancy and dietary characteristics across populations

Nausea and vomiting in pregnancy (NVP) is a pervasive and debilitating phenomenon in humans. Several adaptive explanations for NVP occurrence have been recently proposed, the two most prominent of which predict associations with nutritional intake or specific dietary components. Here we extend previous cross-cultural analyses by analysing associations between NVP prevalence in 56 studies (21 countries) and quantitative estimates of per capita intake across major dietary categories, measured for the year of study by the Food and Agriculture Organisation (FAO). Rates of nausea and vomiting in pregnancy were correlated with high intake of macronutrients (kilocalories, protein, fat, carbohydrate), as well as sugars, stimulants, meat, milk and eggs, and with low intake of cereals and pulses. Restricting analyses to studies from North America and Europe caused relationships between macronutrient intake and NVP to disappear, suggesting that they might be influenced by non-dietary confounds associated with geographical region of study. However, factor analysis of dietary components revealed one factor significantly associated with NVP rate, which was characterized by low cereal consumption and high intake of sugars, oilcrops, alcohol and meat. The results provide further evidence for an association between diet and NVP prevalence across populations, and support for the idea that NVP serves an adaptive prophylactic function against potentially harmful foodstuffs.     

Extreme seasonality of births among nomadic Turkana pastoralists

Births to nomadic Turkana women in northwest Kenya follow one of the most highly seasonal distributions ever reported for a human population, with more than half of all births falling between March and June. Important aspects of the Turkana environment also fluctuate greatly over the course of the year. The rate of conception is apparently highest during the early dry season, when the food supply has been at its best for some time, and when women are attaining their peak nutritional status. The seasonal dynamics of Turkana fertility seem to be driven, ultimately, by fluctuations in rainfall; Fourier analysis indicates that changes in numbers of conceptions follow changes in rainfall with a lag of 3.6 months. The specific biological and behavioral changes in the human population through which the environmental changes may affect fertility are considered.     

Grip strength, muscle fatigue, and body composition in nomadic Turkana pastoralists

Tests of hand grip strength and hand grip muscle fatigue were conducted on Ngisonyoka Turkana pastoralists of northwest Kenya to explore some of the functional relationships between activity and body composition. The test of maximal voluntary contraction (MVC) of hand grip flexors was conducted on 151 Turkana and 38 U.S. men and women. The fatigue test was conducted on the same number of subjects who were instructed to attempt to maintain 80% of the MVC for 90 seconds. The results of these tests, combined with arm measurements of size and body composition, were used to evaluate muscle size and strength relationships and to estimate muscle fiber type distribution in the forearm. MVC values of Turkana men were low by U.S. and European standards. The low values resulted from smaller Turkana muscle areas. MVC values of Turkana women were comparable to those of U.S. and European women, reflecting comparable muscle areas. The fatigue curves of Turkana and U.S. men and women suggest that slow-twitch aerobic muscle fibers predominate for the hand grip flexors of the Turkana pastoralists.     

Is lack of morning sickness teratogenic? A prospective controlled study

BACKGROUND: Case-control studies have suggested that the nausea and vomiting of pregnancy (NVP) may have a protective effect against specific malformations. These suggestions have been interpreted as if the lack of NVP may put mothers at an increased teratogenic risk. METHODS: A prospective, cohort-controlled study was done comparing pregnancy outcome in women not experiencing NVP with those experiencing NVP at two levels of clinical severity. Women who called the Motherisk program about first-trimester exposure to drugs and who had not experienced NVP were included as the study group. The NVP Healthline enrolled two control groups of women with NVP treated with a doxylamine-pyridoxine combination for morning sickness. These women were exposed during the first trimester of gestation to either higher than the standard dose (5-12 tablets/day) or a standard dose (1-4 tablets/day) of doxylamine-pyridoxine. The women in all three groups were followed up four to six months after the expected date of birth to ascertain pregnancy outcomes and child health. RESULTS: There were no major malformations among offspring of 130 women not experiencing NVP. There were two major malformations among 246 women experiencing NVP. The two control groups of women with NVP had similar distributions of gestational ages, birth rates, as well as rates of miscarriages and stillbirths, as in the no-NVP group. CONCLUSIONS: This study did not show an association between lack of NVP and an increase in the overall rates of major malformations.     

The adaptive significance of larval dispersal in coral reef fishes

Synopsis Coral reef fishes almost universally disperse over relatively great distances during a pelagic larval phase. Barlow (1981) suggested that this dispersal is adaptive because adult fishes inhabit a patchy, uncertain environment. This reiterated an older idea that the random extinction of local populations necessarily favours dispersal, since ultimately all populations of non-dispersers will disappear. Whereas this view is based on adult survival, we emphasize a less frequent view that substantial larval dispersal may be adaptive when offspring experience patchy and unpredictable survival in the pelagic habitat. We do not address the question of why these animals ‘broadcast’ rather than ‘brood’, but suggest that species committed to pelagic offspring will be under selection to disperse siblings to spread the risk of failure among members of a cohort. Our arguments are supported by a heuristic computer simulation.     

Correlates of breastfeeding frequency among nomadic pastoralists of Turkana,Kenya: A retrospective study

Recent research has shown that significant variation in breast-feeding behavior exists among natural fertility populations, all of whom have been characterized as practicing “on-demand” breastfeeding. A number of recent prospective studies have contributed to a better understanding of breastfeeding structure and of its consequences for population differences in fertility. Currently, there is a growing interest in quantifying the complex environmental and biocultural interactions which influence that structure; in other words, in establishing an ecology of breastfeeding. In this paper, a carefully structured retrospective study of breastfeeding behavior among nomadic Turkana is used to identify environmental, biobehavioral, and socioeconomic factors associated with variation in breastfeeding frequency among Turkana women. In agreement with the results of a prospective study conducted as part of the same research, the age (growth) and physical development of nurslings show significant correlations with breastfeeding frequency. Maternal physical status, the depth of the maternal social network, and, to a lesser degree, rainfall patterns are also significant. All of these factors appear to influence breastfeeding through their effects on maternal participation in herding activities and related absences from camp. Finally, the study also presents new strategies for collecting and utilizing retrospective data, which are notoriously unreliable and difficult to classify according to operational definitions recently developed for prospective studies. Results of the present study suggest methods by which the quality and reliability of recall data may be enhanced. © 1995 Wiley-Liss, Inc.     

Growth of nomadic and settled Turkana infants of northwest Kenya

Turkana tribespeople reside in a semi-arid savanna ecosystem in northwest Kenya. For over a decade, Ngisonyoka Turkana nomads have been studied within a multidisciplinary framework that embraces ecology, anthropology, and human population biology. Original research objectives of the South Turkana Ecosystem Project were to study nomads longitudinally and within the context of the dry savanna ecosystem. These objectives have been expanded to incorporate settled Turkana who were nomads in the recent past, but who, for a variety of reasons, have taken up a life of sedentary cultivation. The research described here focused on comparisons of growth patterns of nomadic and settled infants from birth to 24 months of age. Infants were measured (recumbent length, weight, head circumference, arm and calf circumference, and selected skinfolds) in 1989 and 1990. Settled infants were slightly longer, but nomadic infants were heavier and fatter. Head circumferences were the same. Some variation was observed by season and year of measurement (from comparative surveys). Both groups showed pronounced weight faltering after 6 months of age when compared with U. S. NCHS reference values. Head circumference faltering was moderate and recumbent length faltering was only slight after 12 months of age. Comparisons of Turkana infant growth in the two populations can contribute indirectly to a better understanding of infant nutritional status, probable morbidity, and other factors, some of which may be linked to female reproduction. © 1993 Wiley-Liss, Inc.     

Attitudes,Perceptions and Potential Uptake of Male Circumcision among Older Men in Turkana County,Kenya Using Qualitative Methods

Background

In many communities, older men (i.e., over 25 years of age) have not come forward for Voluntary Medical Male Circumcision (VMMC) services. Reasons for low demand among this group of men are not well understood, and may vary across geographic and cultural contexts. This paper examines the facilitators and barriers to VMMC demand in Turkana County, Kenya, with a focus on older men. This is one of the regions targeted by the VMMC program in Kenya because the Turkana ethnic group does not traditionally circumcise, and the rates of HIV and STD transmission are high.

Methods and Findings

Twenty focus group discussions and 69 in-depth interviews were conducted with circumcised and uncircumcised men and their partners to elicit their attitudes and perceptions toward male circumcision. The interviews were conducted in urban, peri-urban, and rural communities across Turkana. Our results show that barriers to circumcision include stigma associated with VMMC, the perception of low risk for HIV for older men and their “protection by marriage,” cultural norms, and a lack of health infrastructure. Facilitators include stigma against not being circumcised (since circumcision is associated with modernity), protection against disease including HIV, and cleanliness. It was also noted that older men should adopt the practice to serve as role models to younger men.

Conclusions

Both men and women were generally supportive of VMMC, but overcoming barriers with appropriate communication messages and high quality services will be challenging. The justification of circumcision being a biomedical procedure for protection against HIV will be the most important message for any communication strategy.     

Nutrition, fertility and maternal investment in primates

While the energetics of reproduction have been intensively investigated among women, studies of mother-offspring relationships among non-human primates have tended to neglect the effect of nutrition of the mother on lactational performance and on growth and survival of offspring. Typically fertility has been compared between populations under different nutritional regimes. In this paper, the relations between suckling frequencies, the time of weaning, the survivorship of offspring, the contraceptive effects of lactation and the quality of maternal diets are outlined. Energy transfer from mother to offspring in the form of milk is proposed as a measurable component of maternal investment, and the behavioural causes and consequences of lactational anoestrus are explored using data from free-ranging vervet monkeys. It is suggested that nutrition of the mother is most important during the early phase of rapid infant growth, because at that time the energetic requirements of lactation are high; and that a mother's ability to assess her infant's demands and needs for nutrition for growth leads to alterations in suckling frequencies which result in variation in female fertility.     

Freshwater stingrays from the Plio-Pleistocene of the Turkana Basin, Kenya and Ethiopia

The fossil freshwater stingray from the Turkana Basin of Kenya and Ethiopia is redescribed and reassigned to Dasyatis africana (Arambourg) on the basis of extensive new collections. The ray apparently evolved into an endemic freshwater species derived from a stock which entered the Turkana Basin from the Indian Ocean at about 1.9 Ma. At that time, the ancestral Omo River system flowed through a major lake and exited to the southeast. A fluvial corridor, termed the Turkana River, connected the Turkana Basin with the Indian Ocean. Once established in the basin, the rays flourished and persisted for over half a million years. Their extinction has been placed subsequent to 1.3 Ma, and likely reflects the changing environmental and tectonic conditions recorded in subsequent strata. The fluvial corridor which formed the route of migration into the Turkana Basin has important implications for modern African biogeography as well as that of the past. □ Turkana Basin, Kenya, Ethiopia, Pliocene, Pleistocene, Stingrays, Dasyatidae.     

Geographic variation in the adaptive landscape for seed size at dispersal in the myrmecochorous <Emphasis Type="Italic">Helleborus foetidus</Emphasis>

Literature on seed dispersal mutualisms suggests that plant populations should hardly adapt to their current dispersers. We address the predictions that selection pressures exerted by ants on dispersal-related diaspore traits of the ant-dispersed Helleborus foetidus are highly variable in space, and that geographic (inter-population) variation in these traits is unrelated to selection by current dispersers. To test these predictions we use the concept of the quantitative adaptive landscape for seed size at dispersal. Such landscape depicts the relationship between the population’s mean trait value (mean seed size in the present study) and the population’s mean fitness (mean dispersal probability in the present study). Adaptive landscapes make it possible to assess whether the mean population’s phenotype agrees with one favored by selection. We first analyse, in 12 populations of H. foetidus from southern Spain, the extent of divergence among populations in seed and elaiosome size, and the abundance, composition, and behavior of the ant communities. Seeds from a fixed set of five of these populations were offered to ants in all the study sites to fit the adaptive landscape for seed size. In addition, seeds from the local population were also offered in each site. Our results show that seed size has undergone a larger divergence among populations than elaiosome size. Despite geographic variation in ant assemblages, the adaptive landscapes for seed size at dispersal were remarkably similar among sites: ants create disruptive selection on seed size in 10 out of 12 study sites. As predicted, the basic features of these adaptive landscapes (curvature and location of the minimum) varied geographically in accordance with variation in the size of seed dispersers. Also as predicted, in most populations, the observed mean seed size does not agree with that expected from the adaptive landscapes at dispersal. However, the relevance of dispersers for seed size evolution should not be neglected since the agreement between observed and optimum seed size was stronger where dispersers were more abundant. Thus, against the general view, our results evidence that, in H. foetidus, the observed geographic variation in dispersal-related plant traits is partly linked to selection exerted by current dispersers. Geographic variation in ant assemblages determines both the existence of a selection mosaic and the degree of adjustment of populations to the patterns of selection in the mosaic.     

An evolutionary theory of moral injury with insight from Turkana warriors

Clinicians in Western, Educated, Industrialized, Rich, and Democratic (WEIRD) societies are rethinking whether Post-traumatic Stress Disorder (PTSD) is caused solely by exposure to life-threatening experiences, or also by moral injury—witnessing or participating in acts that violate moral beliefs. However, while there are evolutionary hypotheses explaining PTSD as a response to physical danger, the evolutionary roots of moral injury lack an explanation. We posit that a subset of symptoms of combat-related PTSD is associated with moral injury and that these symptoms evolved in tandem with human's norm-psychology. We can examine this hypothesis by comparing societies with different moral beliefs about warfare, norm enforcement mechanisms, and spheres of moral concern. To illustrate the utility of this framework, we describe combat trauma, war norms, and norm enforcement among Turkana pastoralist warriors in Kenya who participate in highly lethal raids of neighboring ethnic groups. We previously showed that depressive PTSD symptoms in Turkana warriors are more strongly associated with experiencing moral violations in combat, and that Turkana warriors with comparably high overall PTSD symptom-severity experience lower rates of depressive symptoms than US combat veterans. Here we detail aspects of Turkana warfare, moral beliefs, and post-battle rituals that differ from WEIRD societies, and that may ameliorate the symptoms of moral injury in Turkana warriors. Our findings highlight how further studies of combat trauma outside of WEIRD militaries can help evaluate this theory and illustrate the importance of cross-cultural research for identifying the evolutionary roots of combat stress and best practices for prevention and recovery.     

Chronic undernutrition and traditional weaning foods are associated with fat stores in ariaal infants of Northern Kenya

The high proportion of human infant fat is hypothesized to protect infant brains by mobilizing against growth disturbances caused by acute nutritional and pathogen stress during weaning. However, individuals who experience chronic nutritional stress have been shown to store fat rather than mobilize fat stores, although this has not been demonstrated during infancy. This study investigated the relationship between fat development, diet, and nutritional status among 239 breastfeeding Ariaal infants, a group of settled pastoralists who experience both acute and chronic nutritional stress residing in Marsabit District, Kenya. This study had three goals: 1) To investigate the pattern of fat accumulation among Ariaal infants compared with a reference population; 2) to explore the relationship between chronic nutritional stress and fat deposits; and 3) to determine the relationship between traditional weaning foods, particularly cow's milk, and infant's fat. Infants, particularly infants experiencing chronic nutritional stress, were found to accumulate fat deposits in a manner that suggests reduced oxidation of fat stores. Infant upper arm fat area significantly increases with age over the weaning period compared with reference populations, who show a decline in body fat. Chronically undernourished infants were particularly likely to have increased levels of upper arm fat compared with normal infants or acutely undernourished infants. In addition, infants who consume cow's milk are significantly fatter than those that do not. These results suggest that Ariaal infants have both physiological and cultural mechanisms for fat storage in the face of their nutritionally stressed environment. Am J Phys Anthropol 153:286–296, 2014. © 2013 Wiley Periodicals, Inc.     

Analysis of woody vegetation of Corbett National Park,India

The heterogeneous vegetation mosaic of the South Turkana region of north Kenya is associated with diversity in the region's physical environment. The abundance and distribution of the dominant species are related to gradients in those abiotic factors that influence water availability, including precipitation, soil texture, and topographic relief. Research focused on three Acacia species that are a major component of the Turkana vegetation; A. tortilis, A. senegal, and A. reficiens. These species each exhibit a different response to variations in abiotic factors. Consequently, species abundance varies independently across the landscape, creating a continuum of intergrading populations. Community types can be identified within the mosaic of intergrading populations. Although community borders are not discrete due to continual change in species abundance, types are identifiable and are repeated in areas with similar environmental conditions. The landscape patterns are representative of Whittaker's (1953) climaxas-pattern, with communities created by individual patterns of populations responding to environmental gradients, creating a continuum of community change across the landscape.     

Food Aversions and Cravings during Pregnancy on Yasawa Island,Fiji

Women often experience novel food aversions and cravings during pregnancy. These appetite changes have been hypothesized to work alongside cultural strategies as adaptive responses to the challenges posed by pregnancy (e.g., maternal immune suppression). Here, we report a study that assessed whether data from an indigenous population in Fiji are consistent with the predictions of this hypothesis. We found that aversions focus predominantly on foods expected to exacerbate the challenges of pregnancy. Cravings focus on foods that provide calories and micronutrients while posing few threats to mothers and fetuses. We also found that women who experience aversions to specific foods are more likely to crave foods that meet nutritional needs similar to those provided by the aversive foods. These findings are in line with the predictions of the hypothesis. This adds further weight to the argument that appetite changes may function in parallel with cultural mechanisms to solve pregnancy challenges.     

Effect of multiple stress factors (thermal,nutritional and pregnancy type) on adaptive capability of native ewes under semi-arid environment

This study was conducted to evaluate the effect of multiple stress factors (thermal, nutritional and pregnancy type) on two different native track breeds of ewes as reflected by their adaptive capability under semi-arid environment. The multiple stressor experiment was conducted in twenty-four ewes (12 Santa Inês and 12 Morada Nova ewes). Both heat stress and pregnancy stress was common to all four groups. However, the animals were divided into further two groups within each breed on the basis of nutrition regimen. According the groupings were: Group 1 (Six Santa Ines ewes; heat stress; nutrition at 0.5% of BW; single pregnancy); Group 2 (Six Santa Ines ewes; heat stress; nutrition at 1.5% BW; twin pregnancy); groups Group 3 (Six Morada Nova ewes; heat stress; nutrition at 0.5% of BW; single pregnancy); Group 4 (Six Morada Nova ewes; heat stress; nutrition at 1.5% BW; twin pregnancy). All the animals in the experiment were pregnant. Heat stress was induced by exposing all animals to summer heat stress in outside environment while the nutritional regimen followed was at 0.5% and 1.5% level of body weight (BW) respectively in each breed. The experiment was conducted in a completely randomized design with two breeds, two nutritional treatments and two pregnancy types, 10 repetitions for physiological parameters and six for blood parameters, with repeated measures over time. Physiological parameters (respiratory rate, pulse rate and rectal temperature) were measured with the animals at rest in the morning and afternoon, 0600-0700 and 1300–1400 h, respectively, every seven days. Blood samples were collected every 14 d for determination of serum glucose, triglycerides, cholesterol, urea and creatinine. We found interaction effect between breed and pregnancy type on respiratory rate and rectal temperature with greater values in Santa Inês ewes than Morada Nova ewes. However, there was no significant fixed effect of pregnancy type and supplementation level on physiological responses of breeds. Environmental factor (period of the day) had influenced the physiological responses of ewes during all gestational period. Santa Inês ewes had greater serum glucose concentration at 105 d and 120 d of gestation compared to the Morada Nova ewes. Morada Nova ewes had greater concentrations of triglycerides, urea at 120 d, 150 d and also greater cholesterol at 105 d, 135 d and 150 d of gestation compared with Santa Inês ewes. The present result indicates that thermal condition was most important factor that modified the physiological responses of ewes in a semi-arid tropical environment.     

Genetic variability and differentiation of <Emphasis Type="Italic">Caragana microphylla</Emphasis> populations as revealed by RAPD markers

Genetic variability in random amplified polymorphic DNA (RAPD) was studied in 90 individuals of Caragana microphylla, an outcrossing perennial shrub species, from five natural populations sampled in Inner Mongolia steppe of China on a small scale. Nineteen selected primers were used to amplify DNA samples, and totally 225 bands were detected. The percentage of polymorphic bands within populations ranged form 58.22% to 63.56%, with an average of 60% at the population level and 71.11% at the species level, indicating relatively high genetic variations in C. microphylla species. Shannon’s information index (l) and Nei’s gene diversity (h) showed the similar trend with each other. According to the analysis of Nei’s gene diversity, the percentage of genetic variation among populations was 7.13%, indicating a low level of genetic differentiation among populations. There existed a strong gene flow (N _m = 3.26) among populations. Although AMOVA analysis also revealed most variation was within populations (Φ_ST = 4.1%), a significant proportion was observed among populations (P < 0.001) in the present study, suggesting genetic differentiation occurred among populations at a certain extent. Based on Mantel’s tests and the results of previous studies, the genetic structure pattern of C. microphylla accorded with the isolation-by-distance model on a very large scale, however, on a small scale, the significant genetic differentiation among populations might be enhanced by the micro-environmental divergence among the sampling sites, rather than by geographic factors. Analysis of the genetic variations of C. microphylla populations provided useful information for the adaptive strategy of Caragana species.     

Complex Emotions,Complex Problems: Understanding The Experiences Of Perinatal Depression Among New Mothers In Urban Indonesia

In this article, we explore how Javanese women identify and speak of symptoms of depression in late pregnancy and early postpartum and describe their subjective accounts of mood disorders. The study, conducted in the East Java region of Indonesia in 2000, involved in-depth interviews with a subgroup of women (N = 41) who scored above the cutoff score of 12/13 on the Edinburgh Postnatal Depression Scale (EPDS) during pregnancy, at six weeks postpartum, or on both occasions. This sample was taken from a larger cohort study (N cohort = 488) researching the sociocultural factors that contribute to women’s emotional well-being in early motherhood. The women used a variety of Indonesian and Javanese terms to explain their emotional states during pregnancy and in early postpartum, some of which coincided with the feelings described on the EPDS and others of which did not. Women attributed their mood variations to multiple causes including: premarital pregnancy, chronic illness in the family, marital problems, lack of support from partners or family networks, their husband’s unemployment, and insufficient family income due to giving up their own paid work. We argue for the importance of understanding the context of childbearing in order to interpret the meaning of depression within complex social, cultural, and economic contexts.