A multinational case-control study on childhood brain tumours, anthropogenic factors, birth characteristics and prenatal exposures: A validation of interview data.

Little is known about the aetiology of childhood brain tumours. We investigated anthropometric factors (birth weight, length, maternal age), birth characteristics (e.g. vacuum extraction, preterm delivery, birth order) and exposures during pregnancy (e.g. maternal: smoking, working, dietary supplement intake) in relation to risk of brain tumour diagnosis among 7-19 year olds. The multinational case-control study in Denmark, Sweden, Norway and Switzerland (CEFALO) included interviews with 352 (participation rate=83.2%) eligible cases and 646 (71.1%) population-based controls. Interview data were complemented with data from birth registries and validated by assessing agreement (Cohen's Kappa). We used conditional logistic regression models matched on age, sex and geographical region (adjusted for maternal age and parental education) to explore associations between birth factors and childhood brain tumour risk. Agreement between interview and birth registry data ranged from moderate (Kappa=0.54; worked during pregnancy) to almost perfect (Kappa=0.98; birth weight). Neither anthropogenic factors nor birth characteristics were associated with childhood brain tumour risk. Maternal vitamin intake during pregnancy was indicative of a protective effect (OR 0.75, 95%-CI: 0.56-1.01). No association was seen for maternal smoking during pregnancy or working during pregnancy. We found little evidence that the considered birth factors were related to brain tumour risk among children and adolescents.

In Utero Exposure to Antiretroviral Drugs: Effect on Birth Weight and Growth Among HIV-exposed Uninfected Children in Brazil.

BACKGROUND There are concerns about the effects of in utero exposure to antiretroviral drugs (ARVs) on the development of HIV-exposed but uninfected (HEU) children. The aim of this study was to evaluate whether in utero exposure to ARVs is associated with lower birth weight/height and reduced growth during the first 2 years of life. METHODS This cohort study was conducted among HEU infants born between 1996 and 2010 in Tertiary children's hospital in Rio de Janeiro, Brazil. Weight was measured by mechanical scale, and height was measured by measuring board. Z-scores for weight-for-age (WAZ), length-for-age (LAZ) and weight-for-length were calculated. We modeled trajectories by mixed-effects models and adjusted for mother's age, CD4 cell count, viral load, year of birth and family income. RESULTS A total of 588 HEU infants were included of whom 155 (26%) were not exposed to ARVs, 114 (19%) were exposed early (first trimester) and 319 (54%) later. WAZ were lower among infants exposed early compared with infants exposed later: adjusted differences were -0.52 (95% confidence interval [CI]: -0.99 to -0.04, P = 0.02) at birth and -0.22 (95% CI: -0.47 to 0.04, P = 0.10) during follow-up. LAZ were lower during follow-up: -0.35 (95% CI: -0.63 to -0.08, P = 0.01). There were no differences in weight-for-length scores. Z-scores of infants exposed late during pregnancy were similar to unexposed infants. CONCLUSIONS In HEU children, early exposure to ARVs was associated with lower WAZ at birth and lower LAZ up to 2 years of life. Growth of HEU children needs to be monitored closely.

A sex difference in seasonal timing of birth in a livebearing fish

Sex differences in seasonal timing include differences in hatch- or birth-date distribution and differences in the timing of migration or maturation such as protandrous arrival timing (PAT), which is early male arrival at breeding sites. I describe a novel form of protandrous arrival timing, as a sex difference in birth-date distribution in a live-bearing fish (Dwarf Perch, Micrometrus minimus). In this species, birth coincides with arrival at breeding sites because newborn males are sexually active. A series of samples of pregnant females and young of year was collected in Tomales Bay, CA. I analyzed the daily age record in otoliths to estimate the conception date of broods and the age that young-of-year individuals were born. Males were born at a younger age than females, as indicated by the daily age record and also by the predominance of females in broods from which some young had already been born, which was a common occurrence in pregnant females with older embryos. Sex ratio of broods varied with conception date such that early-season broods were predominantly male, possibly as a result of temperature-dependent sex determination. The combined effects of the sex difference in age at birth and seasonal shift in sex ratio were to shift the mean birth date of males relative to females by five days. The most likely ultimate explanation for PAT in the Dwarf Perch is that it arises from exploitation (scramble) competition for mating opportunities among recently-born young-of-year males.

Season of Birth Effects in Autism Spectrum Disorders

One factor that is investigated as a possible clue to etiological factors in Autism Spectrum Disorders (ASD) is season of birth. Season of birth effects could be the result of temperature, toxins, dietary changes, viral infections, and cultural or social factors that change seasonally (Bolton, Pickles, Harrington, Macdonald, & Rutter, 1992). A number of studies have looked for season of birth effects in ASD with no conclusive results. The current study analyzed season of birth effects in a sample of 441 children diagnosed with ASD. Analysis was also repeated after excluding prematurely born children from the data. Level of functioning and gender effects were tested by breaking the sample into a number of sub-groups. While there were no season of birth effects in the sample of all children with ASD when compared to children without ASD in either the entire sample or the non-premature sample, there were significant differences in the season of birth of low functioning children with ASD when compared with high functioning children with ASD.

Effect of maternal weight status on the relationship between prenatal smoking and infant birth weight

The purpose of this study was to assess the effect of maternal pre-pregnancy weight status on the relationship between prenatal smoking and infant birth weight (IBW). Prenatal cigarette smoking and maternal weight exert opposing effects on IBW; smoking decreases birth weight while maternal pre-pregnancy weight is positively correlated with birth weight. As such, mutual effect modification may be sufficiently significant to alter the independent effects of these two birth weight correlates. Finding of such an effect has implications of prenatal smoking cessation education. Perception of risk is an important determinant of smoking cessation, and reduced or low birth weight (LBW) as a smoking-associated risk predominates prenatal smoking counseling and education. In a population such as the US, where obesity is becoming epidemic, particularly among minority and low-income groups, perception of risk may be lowered should increased maternal size attenuate the effect of smoking. Previous studies have not found a significant interaction effect of prenatal smoking and maternal pre-pregnancy weight on IBW; however, use of self-reported smoking status may have biased findings. Reliability of self-reported smoking status reported in the literature is variable, with deception rates ranging from a low of 5% to as high as 16%. This study, using data from a prenatal smoking cessation project, in which smoking status was validated by saliva cotinine, was an opportunity to assess effect modification of smoking and maternal weight using biochemically determined smoking status in lieu of self report. Stratified by saliva cotinine, 151 women from a prenatal smoking cessation cohort, who were 18 years and older and had full-term, singleton births, were included in this study. The effect of smoking in terms of mean birth weight across three levels of maternal pre-pregnancy weight was assessed by general linear modeling procedures, adjusting for other known correlates of IBW. Effect modification was marginally significant, p = .104, but only with control for differential effects among racial/ethnic groups. A smaller than planned sample of nonsmokers, or women who quit smoking during the pregnancy, prohibited rejection of the null hypothesis of no difference in the effect of smoking across levels of pre-pregnancy weight. ^

Progestational agents and preterm birth: An updated review of the literature

The preterm birth rate has been increasing over time in the United States, causing a large social and individual financial burden. Though the cause of preterm birth is now known, risk factors such as a previous preterm birth and a short cervical length have been identified as possible predictors. There are many contributing social and behavioral factors that play a role was well as medical problems that occur before and during pregnancy. Though there have been prevention methods identified, such as prenatal care, tocolytic therapy and cervical cerclage, none of these methods have shown to definitively prevent preterm birth over a long period of time. 17 alpha hydroxyprogesterone has been recognized as a possible prevention method for women at high risk for preterm birth. Three out of the five studies assessed in this review showed a significant reduction in preterm birth with administration of progesterone, both for women with a previous preterm birth and with a short cervical length. Currently there is no standard of care for those at high risk for preterm birth. More large clinical trials need to be conducted to determine if this progesterone for the prevention of preterm birth is effective. ^

Differences in small-for-gestational-age and preterm birth among Asian subgroups in relation to nativity status

This retrospective cohort study examined the association between nativity status and very preterm birth, preterm birth, and small-for-gestational-age (SGA) among Asian subgroups using Texas birth certificate data with no personal identifiers. A total of 877,322 birth certificates of Asian and US-born white women with a singleton birth in Texas from 2001-2004 were analyzed. Birth certificate records of US-born white, Chinese, Japanese, Korean, Vietnamese, Filipino, and Asian Indian women with a singleton birth were included in the analysis. Logistic regressions models were used to explore and understand the differences of the effect of nativity status on birth outcomes in Asian subgroups with US-born whites as the reference group. Most of the Asian subgroups had a lower risk of preterm births compared with US born whites, with reductions in risk ranging from 19% to 49% and the lowest risk of preterm birth observed among foreign-born Chinese mothers. Only Filipino mothers had a higher risk of preterm birth compared to US-born whites. Overall, foreign-born Asians had lower risks for very preterm birth and preterm birth than US-born Asians and US-born whites. US-born Asians were at higher risk for preterm birth than US-born whites. For SGA, all Asian subgroups and Asian subgroups by nativity status were at higher risk of SGA than US-born whites. Asian Indians and Japanese were at highest risk for SGA infants with 2.5 to 3 times the risk of SGA present in US-born whites. Foreign-born Asian women were at higher risk for SGA than their US-born counterparts. This study showed that health disparities among Asian subgroups are hidden by classifying Asians into a single group. By examining Asian subgroups separately and looking at nativity status, the differences in risk of SGA and preterm birth can be revealed so prevention efforts can focus on high risk groups. ^

The association between maternal use of spermicides, condoms, intra-uterine devices or progesterone and major structural birth defects

Birth defects occur in 1 of every 33 babies born in the United States, and are the leading cause of infant death. Mothers using contraceptives that become pregnant may continue to use their contraceptives after their first missed menstrual period, thus exposing their baby in utero to the contraceptive product. Progesterone is also sometimes prescribed during the first trimester of pregnancy to mothers with a history of miscarriages or infertility problems. To ensure the safety of these products, it is important to investigate whether there is an increased occurrence of babies born with birth defects to mothers using various contraceptive methods or progesterone in early pregnancy. Using data from the National Birth Defects Prevention Study (NBDPS), an ongoing multi-state, population based case-control study, this study assessed maternal exposures to IUDs, spermicides, condoms and progesterone in early pregnancy. ^ Progesterone used for threatened miscarriage during the first three months of pregnancy was associated with an increased occurrence of hypoplastic left heart (adjusted odds ratios (OR) 2.24, 95% CI 1.13-4.21), perimembranous ventricular septal defects (OR 1.64, 95% CI 1.10-2.41), septal associations (OR 2.52, 95% CI 1.45-4.24), esophageal atresia (OR 1.82, 95% CI 1.04-3.08), and hypospadias (OR 2.12, 95% CI 1.41-3.18). Mothers using progesterone for injectable contraception had increased (OR > 2.5), but insignificant odds ratios for anencephaly, septal associations, small intestinal atresias and omphalocel. Progesterone used for fertility was not associated with an increased occurrence of any birth defects examined. ^ Mothers using progesterone for fertility assistance and threatened miscarriage were very similar with respect to their demographics and pregnancy history. They also both reported similar types of progesterone. Thus, if progesterone was a causal risk factor for birth defects we would have expected to observe similar increases in risk among mothers using progesterone for both indications. Because we predominantly observed increased associations among mothers using progesterone for threatened miscarriage but not fertility assistance, it is possible the increased associations we observed were confounded by indication (i.e. progesterone was administered for vaginal bleeding which occurred as a sequelae to the formation of a congenital anomaly. ^ No significant increased associations were observed between maternal spermicide use during pregnancy and 26 of 27 types of structural malformations. While multiple statistical tests were performed we observed first trimester maternal spermicide use to be associated with a significant increased occurrence of perimembranous ventricular septal defects (OR 2.21, 95% CI 1.16-4.21). A decreased occurrence (OR < 1.0) was observed for several categories of birth defects among mothers who conceived in the first cycle after discontinuing the use of spermicides (22 of 28) or male condoms (23 of 33). ^ Overall the percent of IUD use was similar between mothers of controls and mothers of all cases in aggregate (crude OR 1.05, 95% CI 0.61-1.84). Power was limited to detect significant associations between IUD use and birth defects, however mothers using an IUD in the month immediately prior to conception or during pregnancy were not associated with an increase of birth defects. Limb defects and amniotic band sequence previously reported to be associated with IUD use during pregnancy were not found to occur among any mothers reporting the use of an IUD during pregnancy.^

Birth prevalence of isolated congenital limb reduction defects in Texas 1999--2001

Objective. Congenital limb defects are common birth defects occurring in approximately 2-7/10,000 live births. Because congenital limb defects are pervasive throughout all populations, and the conditions profoundly affect quality of life, they represent a significant public health concern. Currently there is a paucity of etiologic information in the literature regarding congenital limb reduction defects which represents a major limitation in developing treatment strategies as well as identifying high risk pregnancies. ^ Additionally, despite the fact that the majority of congenital limb reduction defects are isolated, most previous studies have not separated them from those occurring as part of a known syndrome or with multiple additional congenital anomalies of unknown etiology. It stands to reason that factors responsible for multiple congenital anomalies that happen to include congenital limb reduction defects may be quite different from those factors leading to an isolated congenital limb reduction defect. ^ As a first step toward gaining etiologic understanding, this cross-sectional study was undertaken to determine the birth prevalence and obtain demographic information about non-syndromic (isolated) congenital limb reduction defects that occurred in Texas from 1999-2001. ^ Methods. The study population included all infants/fetuses with isolated congenital limb reduction defects born in Texas during 1999-2001; the comparison population was all infants who were born to mothers who were residents of Texas during the same period of time. The overall birth prevalence of limb reduction defects was determined and adjusted for ethnicity, gender, site of defect (upper limb versus lower limb), county of residence, maternal age and maternal education. ^ Results. In Texas, the overall birth prevalence of isolated CLRDs was 2.1/10,000 live births (1.5 and 0.6/10,000 live births for upper limb and lower limb, respectively). ^ The risk of isolated lower limb CLRDs in Texas was significantly lower in females when gender was examined individually (crude prevalence odds ratio of 0.57, 95% CI of 0.36-0.91) as well as in relation to all other variables used in the analysis (adjusted prevalence odds ratio of 0.58, 95% CI of 0.36-0.93). ^ Harris County (which includes the Houston metropolitan area) had significantly lower risks of all (upper limb and lower limb combined) isolated CLRDs when examined in relation to other counties in Texas, with a crude prevalence odds ratio of 0.4 (95% CI: 0.29-0.72) and an adjusted prevalence odds ratio of 0.50 (95% CI: 0.31-0.80). The risk of isolated upper limb CLRDs was significantly lower in Harris County (crude prevalence odds ratio of 0.45, CI of 0.26-0.76 and adjusted prevalence odds ratio of 0.49, CI of 0.28-0.84). This trend toward decreased risk in Harris County was not observed for isolated lower limb reduction defects (adjusted prevalence odds ratio of 0.50, 95% confidence interval: 0.22-1.12). ^ Conclusions. The birth prevalence of isolated congenital limb reduction defects in Texas is in the lower limits of the range of rates that have been reported by other authors for other states (Alabama, Arkansas, California, Georgia, Hawaii, Iowa, Maryland, Massachusetts, North Carolina, Oklahoma, Utah, Washington) and other countries (Argentina, Australia, Austria, Bolivia, Brazil, Canada, Chile, China, Colombia, Costa Rica, Croatia, Denmark, Ecuador, England, Finland, France, Germany, Hungary, Ireland, Israel, Italy, Lithuania, Mexico, Norway, Paraguay, Peru, Spain, Scotland, Sweden, Switzerland, Uruguay, and Venezuela). In Texas, the birth prevalence of isolated congenital lower limb reduction defects was greater for males than females, while the birth prevalence of isolated congenital upper limb reduction defects was not significantly different between males and females. The reduced rates of limb reduction defects in Harris County warrant further investigation. This study has provided an important first step toward gaining etiologic understanding in the study of isolated congenital limb reduction defects. ^

A systematic review of selected birth outcomes in diabetic women who received preconception care and/or used multivitamins prior to pregnancy

Objective. To conduct a systematic review of published literature on preconception care in pre-existing diabetic women looking at the effect of glycemic control and multivitamin usage on the frequency of spontaneous abortion and birth defects.^ Methods. Articles were retrieved from Medline (1950–Dec 2007), Cochrane Library (1800–Dec 2007), Academic Search Complete (Ebsco) (Jan 1800–Dec 2007) and Maternal and Child Health Library (1965–Dec 2007). Studies included women with pre-existing, non-gestational diabetes and a comparison group. Participants must have either received preconception care and/or consumed a multivitamin as part of the study.^ Results. Overall, seven studies met the study criteria and applicability to the study objectives. Four of these reported the frequency of spontaneous abortion. Only one found a statistically significant increased risk of spontaneous abortion among pregnant women who did not receive preconception care compared with those who did receive care, odds ratio 4.32; 95% CI 1.34 to 13.9. Of the seven studies, six reported the frequency of birth defects. Five of these six studies found a significantly increased rate of birth defects among pregnant women who did not receive preconception care compared with those who did receive care, with odds ratios ranging from 1.53 to 10.16. All seven studies based their preconception care intervention on glycemic control. One study also used multivitamins as part of the preconception care.^ Conclusion. Glycemic control was shown to be useful in reducing the prevalence of birth defects, but not as useful in reducing the prevalence of spontaneous abortion. Insulin regimen options vary widely for the diabetic woman. No author excluded or controlled for women who may have been taking a multivitamin on their own. Due to the small amount of literature available, it is still not known which preconception care option, glucose control and/or multivitamin usage, provides better protection from birth defects and spontaneous abortion for the diabetic woman. An area for future investigation would be glycemic control and the use of folic acid started before pregnancy and the effects on birth defects and spontaneous abortion.^

Ethnographic and epidemiologic approaches for the programming of prenatal and birth services in Mesa los Hornos, Mexico

The investigator conducted an action-oriented investigation of pregnancy and birth among the women of Mesa los Hornos, an urban squatter slum in Mexico City. Three aims guided the project: (1) To obtain information for improving prenatal and maternity service utilization; (2) To examine the utility of rapid ethnographic and epidemiologic assessment methodologies; (3) To cultivate community involvement in health development.^ Viewing service utilization as a culturally-bound decision, the study included a qualitative phase to explore women's cognition of pregnancy and birth, their perceived needs during pregnancy, and their criteria of service acceptability. A probability-based community survey delineated parameters of service utilization and pregnancy health events, and probed reasons for decisions to use medical services, lay midwives, or other sources of prenatal and labor and delivery assistance. Qualitative survey of service providers at relevant clinics, hospitals, and practices contributed information on service availability and access, and on coordination among private, social security, and public assistance health service sectors. The ethnographic approach to exploring the rationale for use or non-use of services provided a necessary complement to conventional barrier-based assessment, to inform planning of culturally appropriate interventions.^ Information collection and interpretation was conducted under the aegis of an advisory committee of community residents and service agency representatives; the residents' committee formulated recommendations for action based on findings, and forwarded the mandate to governmental social and urban development offices. Recommendations were designed to inform and develop community participation in health care decision-making.^ Rapid research methods are powerful tools for achieving community-based empowerment toward investigation and resolution of local health problems. But while ethnography works well in synergy with quantitative assessment approaches to strengthen the validity and richness of short-term field work, the author strongly urges caution in application of Rapid Ethnographic Assessments. An ethnographic sensibility is essential to the research enterprise for the development of an active and cooperative community base, the design and use of quantitative instruments, the appropriate use of qualitative techniques, and the interpretation of culturally-oriented information. However, prescribed and standardized Rapid Ethnographic Assessment techniques are counter-productive if used as research short-cuts before locale- and subject-specific cultural understanding is achieved. ^

PRETERM BIRTH AND OCCUPATIONAL PHYSICAL ACTIVITY: A CASE-CONTROL STUDY OF THE RELATIONSHIP BETWEEN LENGTH OF GESTATION AND THE PHYSICAL DEMAND OF U.S. ARMY MILITARY OCCUPATIONAL SPECIALTIES (UNITED STATES)

A case-control study has been conducted examining the relationship between preterm birth and occupational physical activity among U.S. Army enlisted gravidas from 1981 to 1984. The study includes 604 cases (37 or less weeks gestation) and 6,070 controls (greater than 37 weeks gestation) treated at U.S. Army medical treatment facilities worldwide. Occupational physical activity was measured using existing physical demand ratings of military occupational specialties.^ A statistically significant trend of preterm birth with increasing physical demand level was found (p = 0.0056). The relative risk point estimates for the two highest physical demand categories were statistically significant, RR's = 1.69 (p = 0.02) and 1.75 (p = 0.01), respectively. Six of eleven additional variables were also statistically significant predictors of preterm birth: age (less than 20), race (non-white), marital status (single, never married), paygrade (E1 - E3), length of military service (less than 2 years), and aptitude score (less than 100).^ Multivariate analyses using the logistic model resulted in three statistically significant risk factors for preterm birth: occupational physical demand; lower paygrade; and non-white race. Controlling for race and paygrade, the two highest physical demand categories were again statistically significant with relative risk point estimates of 1.56 and 1.70, respectively. The population attributable risk for military occupational physical demand was 26%, adjusted for paygrade and race; 17.5% of the preterm births were attributable to the two highest physical demand categories. ^