The association of timing of repeat cesarean with outcomes among a cohort of Guatemalan women with a history of prior cesarean birth.

BACKGROUND: The objective of this analysis was to observe whether maternal and perinatal/neonatal outcomes of birth vary by timing of repeat cesarean among women with a history of one prior cesarean birth in a Guatemalan cohort. METHODS: This secondary analysis was conducted using data from a prospective study conducted in communities in Chimaltenango, Guatemala through the Global Network for Women's and Children's Health Research. RESULTS: Between January 2017 and April 2020, 26,465 women delivered; 3,143 (11.9%) of those women had a singleton gestation and a history of prior cesarean delivery. 2,210 (79.9%) women with a history of prior cesarean birth had data available on mode of delivery and gave birth by repeat cesarean; 1312 (59.4%) were pre-labor cesareans while 896 (40.5%) were intrapartum cesarean births. Risk factors associated with an increased risk of intrapartum cesarean birth included hospital delivery as compared to "other" location (ARR 1.6 [1.2,2.1]) and dysfunctional labor (ARR 1.6 [1.4,1.9]). Variables associated with a reduced risk of intrapartum cesarean birth were hypertensive disease (ARR 0.7 [0.6,0.9]), schooling (ARR 0.9 [0.8,0.9]), and increasing age, which was associated with a very slight reduction in the outcome (ARR 0.99 [0.98,0.99]). Maternal and neonatal outcomes did not vary by type of cesarean birth. CONCLUSION: Outcomes of cesarean birth do not seem to vary by timing of repeat cesarean birth, with hypertensive disease increasing the likelihood of pre-labor cesarean. This information might be useful in counseling women that outcomes after failed trial of labor do not appear worse than those after pre-labor cesarean birth.

How birth outcomes among a cohort of Guatemalan women with a history of prior cesarean vary by mode or birth across different interpregnancy intervals.

OBJECTIVES: Our objectives were to analyze how pregnancy outcomes varied by cesarean birth as compared to vaginal birth across varying interpregnancy intervals (IPI) and determine if IPI modified mode of birth. METHODS: This secondary analysis used data from a prospective registry of home and hospital births in Chimaltenango, Guatemala from January 2017 through April 2020, through the Global Network for Women's and Children's Health Research. Bivariate comparisons and multivariable logistic regression were used to answer our study question, and the data was analyzed with STATA software v.15.1. RESULTS: Of 26,465 Guatemalan women enrolled in the registry, 2794 (10.6%) had a history of prior cesarean. 560 (20.1%) women delivered by vaginal birth after cesarean with the remaining 2,233 (79.9%) delivered by repeat cesarean. Repeat cesarean reduced the risk of needing a dilation and curettage compared to vaginal birth after cesarean, but this association did not vary by IPI, all p-values > p = 0.05. Repeat cesarean delivery, as compared to vaginal birth after cesarean, significantly reduced the likelihood a woman breastfeeding within one hour of birth (AOR ranged from 0.009 to 0.10), but IPI was not associated with the outcome. Regarding stillbirth, repeat cesarean birth reduced the likelihood of stillbirth as compared to vaginal birth (AOR 0.2), but again IPI was not associated with the outcome. CONCLUSION: Outcomes by mode of delivery among a Guatemalan cohort of women with a history of prior cesarean birth do not vary by IPI.

Caesarean birth by maternal request: a poorly understood phenomenon in low- and middle-income countries.

BACKGROUND: While trends in caesarean birth by maternal request in low- and middle-income countries are unclear, age, education, multiple gestation and hypertensive disease appear associated with the indication when compared with caesarean birth performed for medical indications. METHODS: We performed a secondary analysis of a prospectively collected population-based study of home and facility births using descriptive statistics, bivariate comparisons and multilevel mixed-effects logistic regression. RESULTS: Of 28 751 patients who underwent caesarean birth and had a documented primary indication for the surgery, 655 (2%) were attributed to caesarean birth by maternal request. The remaining 98% were attributed to maternal and foetal indications and prior caesarean birth. In a multilevel mixed effects logistic regression adjusted for site and cluster of birth, when compared with caesareans performed for medical indications, caesarean birth performed for maternal request had a higher odds of being performed among women ≥35 y of age, with a university or higher level of education, with multiple gestations and with pregnancies complicated by hypertension (P < 0.01). Caesarean birth by maternal request was associated with a two-times increased odds of breastfeeding within 1 h of delivery, but no adverse outcomes (when compared with women who underwent caesarean birth for medical indications; P < 0.01). CONCLUSION: Caesarean performed by maternal request is more common in older and more educated women and those with multifoetal gestation or hypertensive disease. It is also associated with higher rates of breastfeeding within 1 h of delivery.

Polyhydramnios among women in a cluster-randomized trial of ultrasound during prenatal care within five low and low-middle income countries: a secondary analysis of the first look study.

BACKGROUND: In many low and low-middle income countries, the incidence of polyhydramnios is unknown, in part because ultrasound technology is not routinely used. Our objective was to report the incidence of polyhydramnios in five low and low-middle income countries, to determine maternal characteristics associated with polyhydramnios, and report pregnancy and neonatal outcomes. METHODS: We performed a secondary analysis of the First Look Study, a multi-national, cluster-randomized trial of ultrasound during prenatal care. We evaluated all women enrolled from Guatemala, Pakistan, Zambia, Kenya and the Democratic Republic of Congo (DRC) who received an examination by prenatal ultrasound. We used pairwise site comparisons with Tukey-Kramer adjustment and multivariable logistic models with general estimating equations to control for cluster-level effects. The diagnosis of polyhydramnios was confrimed by an U.S. based radiologist in a majority of cases (62%). RESULTS: We identified 305/18,640 (1.6%) cases of polyhydramnios. 229 (75%) cases were from the DRC, with an incidence of 10%. A higher percentage of women with polyhydramnios experienced obstructed labor (7% vs 4%) and fetal malposition (4% vs 2%). Neonatal death was more common when polyhydramnios was present (OR 2.43; CI 1.15, 5.13). CONCLUSIONS: Polyhydramnios occured in these low and low-middle income countries at a rate similar to high-income contries except in the DRC where the incidence was 10%. Polyhydramnios was associated with obstructed labor, fetal malposition, and neonatal death. TRIAL REGISTRATION: NCT01990625 , November 21, 2013.

Challenges of Implementing an Individual Randomized Controlled Trial (Women First: Preconception Maternal Nutrition Study) in a Rural Study Site: A Case Study From Pakistan.

Persistent global disparities in maternal and neonatal outcomes associated with poor maternal nutrition provided the genesis of the Women First (WF) study, an individually randomized controlled trial on preconceptional maternal nutrition. This article describes the challenges that arose in implementing this trial related to nutrition or diet of the mother, in District Thatta-Pakistan. During different phases of the study, we encountered problems in identifying the eligible participants, taking consent from couples, randomizing participants in different arms, conducting biweekly follow-up visits on time, ensuring compliance to the intervention, and measuring the primary outcome within the 24 hours of birth. Each challenge was itself an opportunity for the research team to address the same through effective coordination and teamwork. Moreover, with adequate resources and dedicated staff with diverse backgrounds, it was possible to implement the WF study across the widely scattered geographic clusters of District Thatta. In addition, there are some broad strategies that could be applied to other studies such as very close contact either in person or at least by talking to mothers via phones and rapport with the study participants, the study leadership of country coordinator and the field supervisors to build trust between those on front lines and the study leadership. Moreover, continuous monitoring and supervision with frequent training and refreshers were also found to be more important to assure the data quality and to meet the study targets. Community meetings were also found to be very helpful and effective to follow the participants for a long time. Researchers conducting a similar type of studies particularly in rural areas can learn many lessons from such experiences. Thus, the process of implementing the study in one of the rural areas of Pakistan provides an insight into where and how similar individual randomized trials might be deployed.

Food insecurity and nutritional status of preconception women in a rural population of North Karnataka, India.

BACKGROUND: As per the World Health Organization, the nutritional status of women of reproductive age is important, as effects of undernutrition are propagated to future generations. More than one-third of Indian women in the reproductive age group are in a state of chronic nutritional deficiency during the preconception period leading to poor health and likely resulting in low birth weight babies. This study was aimed to assess the food insecurity and nutritional status of preconception women in a rural population of north Karnataka. METHODS: A total of 770 preconception women were enrolled across a district in Karnataka from selected primary health centre areas by a cluster sampling method. Data on socioeconomic status, food insecurity and obstetric history were collected by trained research assistants, interviewing women at home. In half of the participants, a 1 day 24 -hour dietary recalls were conducted by dietary assistants to assess the dietary intakes. Anthropometric measurements and haemoglobin estimation were carried out at the health centres. RESULTS: In the present study, a majority of the participants (64.8%) belonged to the lower socio-economic classes and the prevalence of food insecurity was 27.4%. A majority of the participants had mild (15.5%) to moderate (78.6%) anaemia. About one-third of the participants (36.6%) were underweight. Significant associations were found between socio-economic status and anaemia (p = 0.0006) and between food insecurity and anaemia (p = 0.0001). CONCLUSION: The nutritional status of preconception women was poor and anemia was more prevalent in low-socioeconomic and food insecure population.

Exchangeable Zinc Pool Size at Birth in Pakistani Small for Gestational Age and Appropriate for Gestational Age Infants Do Not Differ But Are Lower Than in US Infants.

OBJECTIVES: Small for gestational age (SGA) infants are more susceptible to infectious morbidity and growth faltering compared to their appropriate for gestational age (AGA) counterparts. Zinc supplementation of SGA infants may be beneficial but the underlying susceptibility to zinc deficiency of SGA infants has not been examined. METHODS: In a community-based, observational, longitudinal study in a peri-urban settlement of Karachi, Pakistan, we compared the size of the exchangeable zinc pools (EZPs) in term SGA and AGA infants at birth and at 6 months of age, hypothesizing that the EZP would be lower in the SGA group. To measure EZP size, a zinc stable isotope was intravenously administered within 48 hours of birth (n = 17 and 22) at 6 months (n = 11 and 14) in SGA and AGA infants, respectively. Isotopic enrichment in urine was used to determine EZP. RESULTS: No significant difference was detected in the mean (±standard deviation) EZP between SGA and AGA infants at birth, with values of 9.8 ±â€Š3.5 and 10.1 ±â€Š4.1 mg/kg, respectively (P = 0.86), or at 6 months. Longitudinal EZP measurements demonstrated a significant decline in EZP relative to body weight in both groups at 6 months (P < 0.001). Mean EZP (adjusted for body weight) size at birth for the combined Pakistani groups was significantly lower than AGA infants at birth in the United States (P = 0.017). CONCLUSIONS: These results did not support a difference in zinc endowment between SGA and AGA Pakistani infants. They, however, do suggest lower in utero zinc transfer to the fetus in a setting where poor maternal nutritional status may confer a high susceptibility to postnatal zinc deficiency.

Enhancing Periconceptional Health by Targeting Postpartum Mothers at Rural WIC Clinics.

The overall goal of this pilot quality improvement (QI) intervention was to (1) assess the feasibility of making a WIC (Women, Infants, and Children) systems-level change that added measurement of maternal weight and discussion of maternal health habits into each postpartum maternal and offspring visit in rural clinics in Colorado and (2) assess the impacts of the intervention on maternal diet, physical activity, and weight status. A mixed-method evaluation approach was used involving the collection of quantitative data (HeartSmartMoms usage reports, manual WIC chart reviews [to calculate screening rates], pre-/postsurveys, and weight status [body mass index]) and qualitative data (focus groups and project team meeting minutes). It was determined it is feasible to make a short-term systems-level change; however, many barriers were encountered in doing so, and the results were not sustained. The QI intervention did decrease participants' daily consumption of sugar-sweetened beverages and maternal weight status (controlling for maternal age and language), but did not improve any other eating/physical activity behaviors. Lessons learned and recommendations to improve the implementation of health promotion interventions aimed at improving postpartum maternal health, which can increase health during the periconceptional phase, and in turn, improve the health outcomes for a child, are discussed.

Data quality monitoring and performance metrics of a prospective, population-based observational study of maternal and newborn health in low resource settings.

BACKGROUND: To describe quantitative data quality monitoring and performance metrics adopted by the Global Network's (GN) Maternal Newborn Health Registry (MNHR), a maternal and perinatal population-based registry (MPPBR) based in low and middle income countries (LMICs). METHODS: Ongoing prospective, population-based data on all pregnancy outcomes within defined geographical locations participating in the GN have been collected since 2008. Data quality metrics were defined and are implemented at the cluster, site and the central level to ensure data quality. Quantitative performance metrics are described for data collected between 2010 and 2013. RESULTS: Delivery outcome rates over 95% illustrate that all sites are successful in following patients from pregnancy through delivery. Examples of specific performance metric reports illustrate how both the metrics and reporting process are used to identify cluster-level and site-level quality issues and illustrate how those metrics track over time. Other summary reports (e.g. the increasing proportion of measured birth weight compared to estimated and missing birth weight) illustrate how a site has improved quality over time. CONCLUSION: High quality MPPBRs such as the MNHR provide key information on pregnancy outcomes to local and international health officials where civil registration systems are lacking. The MNHR has measures in place to monitor data collection procedures and improve the quality of data collected. Sites have increasingly achieved acceptable values of performance metrics over time, indicating improvements in data quality, but the quality control program must continue to evolve to optimize the use of the MNHR to assess the impact of community interventions in research protocols in pregnancy and perinatal health. TRIAL REGISTRATION NUMBER: NCT01073475.

Zinc Absorption from Fortified Milk Powder in Adolescent Girls.

Zinc (Zn) is essential for development, growth, and reproduction. The Mexican government subsidizes micronutrient-fortified milk for risk groups, with positive effect on the targeted groups' plasma Zn level, inferring a good absorption is achieved although it has not being measured. The aim of this study was to determine the impact of micronutrient-fortified milk intake during 27 days on Zn absorption in adolescent girls from northwest Mexico. Therefore, Zn absorption was evaluated in 14 healthy adolescent girls (14.1 years old) with adequate plasma Zn levels, before and after 27 days of fortified Zn milk intake. Fractional Zn absorption (FZA) was calculated from urinary ratios of stable isotopic Zn tracers administered orally and intravenously on days 0 and 27, and total absorbed Zn (TZA) was calculated. At the beginning, Zn intake was 6.8 ± 0.85 mg/d (mean ± SE), and 50 % of the adolescent girls did not achieve their requirement (7.3 mg/d). Additionally, FZA was negatively correlated with Zn intake (r =-0.61, p = 0.02), while TZA (1.06 mg/d) was insufficient to cover the physiologic requirements of adolescent girls (3.02 mg/d). At the end of the intervention, all the girls reached the Zn intake recommendation and TZA, 3.09 mg/d, which was enough to meet the physiological requirement for 57 % of the adolescent girls. Therefore, the low Zn intake and the Zn status of adolescent girls were positively impacted by Zn-fortified milk intake and its good absorption rate.

Zinc in plasma and breast milk in adolescents and adults in pregnancy and pospartum: a cohort study in Uruguay.

OBJECTIVE: To assess if age is a risk factor for low zinc nutritional status in pregnancy, postpartum and in breast milk concentration, and the association between mother zinc plasma level with zinc milk concentration. DESIGN: Cohort study comparing adolescents with adult women, with < 14 weeks of gestation at first prenatal care. Socio demographic and plasma zinc data were collected at that moment and at postpartum time (4 + 1 month). Milk zinc concentrations were also measured at 4 th month postpartum. SETTING: Women were recruited from 16 public primary health care services in Uruguay Subjects: 151 adolescents and 161 adult women. RESULTS: Adolescent average plasma zinc at < 14 weeks of gestation was 84.4 ± 3.6 ug /dl and did not differ significantly from that for adult women (85.2 ± 13.6 ug/dl). Prevalence of hypozincemia was relatively low with but with no difference by age (14.6% in adolescents and 12.3% in adults). Zinc concentrations in breast milk were similar for adolescents, 1.24 mg. /L (CI 1.06 to 1.44) and adult women, 1.27 mg./L (CI .1.0-1.46). There was no correlation between plasma zinc and breast milk zinc concentrations in adults and a weak correlation in adolescents (- 0.27, P <0.05). CONCLUSIONS: Prevalence of hypozincemia in pregnancy was relatively low but similar in adolescents and adult women. Neither pregnancy nor age had negative consequences over postpartum plasma zinc, nor over breast milk zinc concentrations. No correlation was found between mother s plasma zinc and breast milk levels.

Objetivo: Evaluar la edad como factor de riego para el déficit nutricional de zinc en el embarazo y en el posparto y la correlación entre la concentración de zinc plasmático y de la leche materna. Diseño: Estudio de cohorte de 151 embarazadas adolescentes y 161 adultas con < 14 semanas de gestación al primer control prenatal, seleccionadas en 16 centros públicos de salud de primer nivel de atención de Uruguay. Se obtuvieron datos socio demográficos y se determinó zinc plasmático al primer control prenatal y 4 meses posparto (± 1 mes). En el último control se midió también la concentración de zinc en la leche materna. Resultados: La media de concentración de zinc plasmático a las 14 semanas de gestación fue 84.4 ± 3.6 ug. /dl sin diferencias significativas con las adultas (85.2 ± 13.6 ug/dl). La prevalencia de hipozincemia fue relativamente baja, sin diferencias entre los grupos (14.6% en adolescentes y 12.3% en adultas). La concentración de zinc en la leche materna fue similar en adolescentes y adultas (1.2 CI 1.1-1.4 mg. /L en el grupo total). No se encontró correlación entre el nivel plasmático de zinc materno y la concentración en la leche en adultas y una débil correlación en el grupo de adolescentes (-0.27, P <0.05). Conclusión: La prevalencia de hipozincemia en el embarazo es relativamente baja y similar entre adultas y adolescentes. No se observó relación entre la edad materna y los niveles plasmáticos de zinc post parto en la madre ni en la leche materna. La concentración de zinc plasmático materno no se correlacionó con el zinc en la leche materna.

Lactation and neonatal nutrition: defining and refining the critical questions.

This paper resulted from a conference entitled "Lactation and Milk: Defining and refining the critical questions" held at the University of Colorado School of Medicine from January 18-20, 2012. The mission of the conference was to identify unresolved questions and set future goals for research into human milk composition, mammary development and lactation. We first outline the unanswered questions regarding the composition of human milk (Section I) and the mechanisms by which milk components affect neonatal development, growth and health and recommend models for future research. Emerging questions about how milk components affect cognitive development and behavioral phenotype of the offspring are presented in Section II. In Section III we outline the important unanswered questions about regulation of mammary gland development, the heritability of defects, the effects of maternal nutrition, disease, metabolic status, and therapeutic drugs upon the subsequent lactation. Questions surrounding breastfeeding practice are also highlighted. In Section IV we describe the specific nutritional challenges faced by three different populations, namely preterm infants, infants born to obese mothers who may or may not have gestational diabetes, and infants born to undernourished mothers. The recognition that multidisciplinary training is critical to advancing the field led us to formulate specific training recommendations in Section V. Our recommendations for research emphasis are summarized in Section VI. In sum, we present a roadmap for multidisciplinary research into all aspects of human lactation, milk and its role in infant nutrition for the next decade and beyond.

Training traditional birth attendants on the WHO Essential Newborn Care reduces perinatal mortality.

OBJECTIVES: To evaluate the impact of birth attendant training using the World Health Organization Essential Newborn Care (ENC) course among traditional birth attendants, with a particular emphasis on the effect of acquisition of skills on perinatal outcomes. DESIGN: Population-based, prospective, interventional pre-post design study. SETTING: 11 rural clusters in Chimaltenango, Guatemala. POPULATION: Health care providers. METHODS: This study analyzed the effect of training and implementation of the ENC health care provider training course between September 2005 and December 2006. OUTCOME MEASURES: The primary outcome measure was the rate of death from all causes in the first seven days after birth in fetuses/infants ≥1500g. Secondary outcome measures were overall rate of stillbirth, rate of perinatal death, which included stillbirths plus neonatal deaths in the first seven days in fetuses/infants ≥1500g. RESULTS: Perinatal mortality decreased from 39.5/1000 pre-ENC to 26.4 post-ENC (RR 0.72; 95%CI 0.54-0.97). This reduction was attributable almost entirely to a decrease in the stillbirth rate of 21.4/1000 pre-Essential Newborn Care to 7.9/1000 post-ENC (RR 0.40; 95%CI 0.25-0.64). Seven-day neonatal mortality did not decrease (18.3/1000 to 18.6/1000; RR 1.05; 95%CI 0.70-1.57). CONCLUSION: Essential Newborn Care training reduced stillbirths in a population-based controlled study with deliveries conducted almost exclusively by traditional birth attendants. Scale-up of this intervention in other settings might help assess reproducibility and sustainability.

Bioavailability of zinc oxide added to corn tortilla is similar to that of zinc sulfate and is not affected by simultaneous addition of iron.

BACKGROUND: Corn tortilla is the staple food of Mexico and its fortification with zinc, iron, and other micronutrients is intended to reduce micronutrient deficiencies. However, no studies have been performed to determine the relative amount of zinc absorbed from the fortified product and whether zinc absorption is affected by the simultaneous addition of iron. OBJECTIVE: To compare zinc absorption from corn tortilla fortified with zinc oxide versus zinc sulfate and to determine the effect of simultaneous addition of two doses of iron on zinc bioavailability. METHODS: A randomized, double-blind, crossover design was carried out in two phases. In the first phase, 10 adult women received corn tortillas with either 20 mg/kg of zinc oxide added, 20 mg/kg of zinc sulfate added, or no zinc added. In the second phase, 10 adult women received corn tortilla with 20 mg/kg of zinc oxide added and either with no iron added or with iron added at one of two different levels. Zinc absorption was measured by the stable isotope method. RESULTS: The mean (+/- SEM) fractional zinc absorption from unfortified tortilla, tortilla fortified with zinc oxide, and tortilla fortified with zinc sulfate did not differ among treatments: 0.35 +/- 0.07, 0.36 +/- 0.05, and 0.37 +/- 0.07, respectively. The three treatment groups with 0, 30, and 60 mg/kg of added iron had similar fractional zinc absorption (0.32 +/- 0.04, 0.33 +/- 0.02, and 0.32 +/- 0.05, respectively) and similar amounts of zinc absorbed (4.8 +/- 0.7, 4.5 +/- 0.3, and 4.8 +/- 0.7 mg/day, respectively). CONCLUSIONS: Since zinc oxide is more stable and less expensive and was absorbed equally as well as zinc sulfate, we suggest its use for corn tortilla fortification. Simultaneous addition of zinc and iron to corn tortilla does not modify zinc bioavailability at iron doses of 30 and 60 mg/kg of corn flour.

Hemoglobin, growth, and attention of infants in southern Ethiopia.

Male and female infants from rural Ethiopia were tested to investigate relations among hemoglobin (Hb), anthropometry, and attention. A longitudinal design was used to examine differences in attention performance from 6 (M = 24.9 weeks, n = 89) to 9 months of age (M = 40.6 weeks, n = 85), differences hypothesized to be related to changes in iron status and growth delays. Stunting (length-for-age z scores < -2.0) and attention performance, t(30) = -2.42, p = .022, worsened over time. Growth and Hb predicted attention at 9 months, R(2) = .15, p < .05, but not at 6. The study contributes to the knowledge base concerning the relations among Hb, early growth, and attention.

High mortality rates for very low birth weight infants in developing countries despite training.

OBJECTIVE: The goal was to determine the effect of training in newborn care and resuscitation on 7-day (early) neonatal mortality rates for very low birth weight (VLBW) infants. The study was designed to test the hypothesis that these training programs would reduce neonatal mortality rates for VLBW infants. METHODS: Local instructors trained birth attendants from 96 rural communities in 6 developing countries in protocol and data collection, the World Health Organization Essential Newborn Care (ENC) course, and a modified version of the American Academy of Pediatrics Neonatal Resuscitation Program (NRP), by using a train-the-trainer model. To test the impact of ENC training, data on infants of 500 to 1499 g were collected by using a before/after, active baseline, controlled study design. A cluster-randomized, controlled trial design was used to test the impact of the NRP. RESULTS: A total of 1096 VLBW (500-1499 g) infants were enrolled, and 98.5% of live-born infants were monitored to 7 days. All-cause, 7-day neonatal mortality, stillbirth, and perinatal mortality rates were not affected by ENC or NRP training. CONCLUSIONS: Neither ENC nor NRP training of birth attendants decreased 7-day neonatal, stillbirth, or perinatal mortality rates for VLBW infants born at home or at first-level facilities. Encouragement of delivery in a facility where a higher level of care is available may be preferable when delivery of a VLBW infant is expected.

The global network: a prospective study of stillbirths in developing countries.

OBJECTIVE: Our goal was to determine stillbirth rates in a multisite population-based study in community settings in the developing world. STUDY DESIGN: Outcomes of all community deliveries in 5 resource-poor countries (Democratic Republic of Congo, Guatemala, India, Zambia, and Pakistan) and in 1 mid-level country (Argentina) were evaluated prospectively over an 18-month period. Births of > 1000 g with no signs of life were defined as stillbirth. RESULTS: Outcomes of 60,324 deliveries were included. Stillbirth rates ranged from 34 per 1000 in Pakistan to 9 per 1000 births in Argentina. Increased stillbirth rates were associated significantly with lower skilled providers, out-of-hospital births, and low cesarean section rates. Maceration was present in 17.2% of stillbirths. CONCLUSION: The stillbirth rates among births of > or = 1000 g in these developing countries were substantially higher than reported stillbirth rates in developed countries (3-5/1000 births). Because most developed countries define stillbirth as > or = 20 weeks of gestation or > or = 500 g and because almost one-half of all stillbirths are < 1000 g, the developing/developed country difference is actually larger than apparent from this study. Maceration was uncommon, which indicates that most of the deaths probably occurred during labor. The low rates of physician attendance, hospital delivery, and cesarean section deliveries suggest that stillbirth rates could be reduced by access to higher quality institutional deliveries.

The usefulness of in vitro models to predict the bioavailability of iron and zinc: a consensus statement from the HarvestPlus expert consultation.

A combination of dietary and host-related factors determines iron and zinc absorption, and several in vitro methods have been developed as preliminary screening tools for assessing bioavailability. An expert committee has reviewed evidence for their usefulness and reached a consensus. Dialyzability (with and without simulated digestion) gives some useful information but cannot predict the correct magnitude of response and may sometimes predict the wrong direction of response. Caco-2 cell systems (with and without simulated digestion) have been developed for iron availability, but the magnitude of different effects does not always agree with results obtained in human volunteers, and the data for zinc are too limited to draw conclusions about the validity of the method. Caco-2 methodologies vary significantly between laboratories and require experienced technicians and good quality cell culture facilities to obtain reproducible results. Algorithms can provide semi-quantitative information enabling diets to be classified as high, moderate, or low bioavailability. While in vitro methods can be used to generate ideas and develop hypotheses, they cannot be used alone for important decisions concerning food fortification policy, selection of varieties for plant breeding programs, or for new product development in the food industry. Ultimately human studies are required for such determinations.

Underwood Memorial Lecture: human zinc homeostasis: good but not perfect.

Three selected aspects of human zinc homeostasis and requirements are reviewed with special reference to studies undertaken by the author and his colleagues: 1) the implications for the calculation of physiologic requirements for zinc of the interrelationship between two key variables of zinc homeostasis, intestinal excretion of endogenous zinc and total absorbed zinc, are examined at levels of absorption below those necessary to meet physiologic requirements; 2) a method for deriving average dietary zinc requirements from zinc-stable isotope tracer/metabolic studies is illustrated with examples of studies being conducted in developing countries; and 3) the effect of reduction of high intakes of phytic acid on zinc bioavailability is examined with test meals prepared from low-phytic-acid maize or isohybrid wild-type control maize.