California Birth Research Articles

Association Between PM2.5 and PM2.5 Constituents and Preterm Birth in California, 2000-2006

Particulate matter (PM) has been associated with an increased risk of preterm birth (PTB) in many studies. However, few have investigated the relationship between individual constituents of fine PM...

A ‘busy day’ effect on perinatal complications of delivery on weekends: a retrospective cohort study

ObjectiveTo evaluate whether busy days on a labour and delivery unit are associated with maternal and neonatal complications of childbirth in California hospitals, accounting for weekday/weekend births.DesignThis is a population-based retrospective cohort study.SettingLinked vital statistics/patient discharge data for California births between 2009 and 2010 from the Office of Statewide Health Planning and Development.ParticipantsAll singleton, cephalic, non-anomalous California births between 2009 and 2010 (N=724 967).Main outcomesThe key exposure was high daily obstetric volume, defined as giving birth on a day when the number of births exceeded the hospital-specific 75th percentile of daily delivery volume. Outcomes were a range of maternal and neonatal complications.ResultsSeveral maternal and neonatal complications were increased on high-volume days and weekends following adjustment for maternal demographics, annual hospital birth volume and teaching hospital status. For example, compared with low-volume weekdays, the odds of Apgar <7 on low-volume weekend days and high-volume weekend days were 11% (adjusted OR (aOR) 1.11, CI 1.03 to 1.21) and 29% higher (aOR 1.29, CI 1.10 to 1.52), respectively. High volume was associated with increased odds of neonatal seizures on weekdays (aOR 1.33, CI 1.01 to 1.71) and haemorrhage on weekends (aOR 1.11, CI 1.01 to 1.22). After accounting for between-hospital variation, weekend delivery remained significantly associated with increased odds of Apgar score <7, neonatal intensive care unit admission, prolonged maternal length of stay and the odds of neonatal seizures remained increased on high-volume weekdays.ConclusionsOur findings suggest that weekend delivery is a consistent risk factor for a range of perinatal complications and there may be variability in how well hospitals handle surges in volume.

Contrasts in the movements and habitat use of juvenile and adult white sharks (Carcharodon carcharias) at Guadalupe Island, Mexico

Although the effort in the study of white sharks in Mexico is rapidly elucidating adult biology, almost nothing is known about the juveniles. Current understanding of this life history is based largely on the incidental take of juveniles in nursery grounds in the Pacific coast of Baja California and some individuals tagged in the USA that have migrated to Mexican waters. Also, it is not known how or when they recruit to adult aggregation sites or how they learn to make seasonal migrations offshore. Five white sharks were manually tracked using ultrasonic transmitters with depth and temperature sensors between 2006 and 2007. Additional white sharks were tagged (N = 60) with long-lived coded transmitters and detected at listening stations located on the west coast of the United States of America and Guadalupe Island (GI) from August 2008 to October 2015. We found that: (1) juvenile white sharks remained close to the island throughout the day between the surface and 50 m depth in warm waters (from 14 to 20 °C), whereas the adults moved offshore into deep waters during the day and stayed close to the island during the night presenting a broader tolerance of colder waters (from 9 to 20 °C); (2) tagged white sharks had a positive correlation between total length and habitat range, and the core areas of adults were related to pinniped colonies; (3) adults patrolled in deep waters in November and December when the northern elephant seals (NESs) returned back to the island for pupping with their mean mass higher than during the winter post-breeding migration; (4) tagged juvenile white sharks remained near the island for 12–14 months before departing; and (5) tagged subadults undertook coastal migrations before starting their offshore migrations. The data collected in our study suggest that white shark juveniles arrive to GI from nursery grounds on the mainland after they have reached at least 180 cm TL; then, they remained around the island for several months, potentially taking advantage of the diversity of prey. In addition, they may start their first offshore migrations, coming back to their nursery grounds and GI before they reach maturity, while at GI juveniles stayed close to the shore and in shallow water to avoid adults, probably feeding on demersal prey and species that perform nocturnal migrations such as squid and mackerel. It is argued that the distribution of the large white sharks in GI is controlled by the availability of NES and that adult white sharks look for this prey in deep waters during the day in the vicinity of the seal colonies, taking advantage of the great visibility of GI waters. It is also possible that white sharks take advantage of NES in GI before they go to their pupping grounds to give birth in California and Baja California or to their offshore migration to the west.

Risk of preterm birth by subtype among Medi-Cal participants with mental illness

Previous studies have demonstrated an association between mental illness and preterm birth (before 37 weeks). However, these investigations have not simultaneously considered gestation of preterm birth, the indication (eg, spontaneous or medically indicated), and specific mental illness classifications. The objective of the study was to examine the likelihood of preterm birth across gestational lengths and indications among Medi-Cal (California's Medicaid program) participants with a diagnostic code for mental illness. Mental illnesses were studied by specific illness classification. The study population was drawn from singleton live births in California from 2007 through 2011 in the birth cohort file maintained by the California Office of Statewide Health Planning and Development, which includes birth certificate and hospital discharge records. The sample was restricted to women with Medi-Cal coverage for prenatal care. Women with mental illness were identified using International Classification of Diseases, ninth revision, codes from their hospital discharge record. Women without a mental illness International Classification of Diseases, ninth revision, code were randomly selected at a 4:1 ratio. Adjusting for maternal characteristics and obstetric complications, relative risks and 95% confidence intervals were calculated for preterm birth comparing women with a mental illness diagnostic code with women without such a code. We identified 6198 women with a mental illness diagnostic code and selected 24,792 women with no such code. The risk of preterm birth in women with a mental illness were 1.2 times higher than women without a mental illness (adjusted relative risk, 1.2, 95% confidence interval, 1.1-1.3). Among the specific mental illnesses, schizophrenia, major depression, and personality disorders had the strongest associations with preterm birth (adjusted relative risks, 2.0, 2.0 and 3.3, respectively). Women receiving prenatal care through California's low-income health insurance who had at least 1 mental illness diagnostic code were 1.2-3.3-times more likely to have a preterm birth than women without a mental illness, and these risks persisted across most illness classifications. Although it cannot be determined from these data whether specific treatments for mental illness contribute to the observed associations, elevated risk across different diagnoses suggests that some aspects of mental illness itself may confer risk.

The Impact of maternal obesity and race/ethnicity on perinatal outcomes: Independent and joint effects.

Independent and joint impacts of maternal race/ethnicity and obesity on adverse birth outcomes, including pre-eclampsia, low birth weight, and macrosomia, were characterized. Retrospective cohort study of all 2007 California births was conducted using vital records and claims data. Maternal race/ethnicity and maternal body mass index (BMI) were the key exposures; their independent and joint impact on outcomes using regression models was analyzed. Racial/ethnic minority women of normal weight generally had higher risk as compared with white women of normal weight (e.g., African-American women, pre-eclampsia adjusted odds ratio [aOR] 1.60, 95% confidence interval [CI]: 1.48-1.74 vs. white women). However, elevated BMI did not usually confer additional risk (e.g., pre-eclampsia aOR comparing African-American women with excess weight with white women with excess weight, 1.17, 95% CI: 0.89-1.54). Obesity was a risk factor for low birth weight only among white women (excess weight aOR, 1.24, 95% CI: 1.04-1.49 vs. white women of normal weight) and not among racial/ethnic minority women (e.g., African-American women, 0.95, 95% CI: 0.83-1.08). These findings add nuance to our understanding of the interplay between maternal race/ethnicity, BMI, and perinatal outcomes. While the BMI/adverse outcome gradient appears weaker in racial/ethnic minority women, this reflects the overall risk increase in racial/ethnic minority women of all body sizes.

Low birth weight and air pollution in California: Which sources and components drive the risk?

IntroductionIntrauterine growth restriction has been associated with exposure to air pollution, but there is a need to clarify which sources and components are most likely responsible. This study investigated the associations between low birth weight (LBW, <2500g) in term born infants (≥37 gestational weeks) and air pollution by source and composition in California, over the period 2001–2008. MethodsComplementary exposure models were used: an empirical Bayesian kriging model for the interpolation of ambient pollutant measurements, a source-oriented chemical transport model (using California emission inventories) that estimated fine and ultrafine particulate matter (PM2.5 and PM0.1, respectively) mass concentrations (4km×4km) by source and composition, a line-source roadway dispersion model at fine resolution, and traffic index estimates. Birth weight was obtained from California birth certificate records. A case-cohort design was used. Five controls per term LBW case were randomly selected (without covariate matching or stratification) from among term births. The resulting datasets were analyzed by logistic regression with a random effect by hospital, using generalized additive mixed models adjusted for race/ethnicity, education, maternal age and household income. ResultsIn total 72,632 singleton term LBW cases were included. Term LBW was positively and significantly associated with interpolated measurements of ozone but not total fine PM or nitrogen dioxide. No significant association was observed between term LBW and primary PM from all sources grouped together. A positive significant association was observed for secondary organic aerosols. Exposure to elemental carbon (EC), nitrates and ammonium were also positively and significantly associated with term LBW, but only for exposure during the third trimester of pregnancy. Significant positive associations were observed between term LBW risk and primary PM emitted by on-road gasoline and diesel or by commercial meat cooking sources. Primary PM from wood burning was inversely associated with term LBW. Significant positive associations were also observed between term LBW and ultrafine particle numbers modeled with the line-source roadway dispersion model, traffic density and proximity to roadways. DiscussionThis large study based on complementary exposure metrics suggests that not only primary pollution sources (traffic and commercial meat cooking) but also EC and secondary pollutants are risk factors for term LBW.

Body Mass Index Change between Pregnancies and Risk of Spontaneous Preterm Birth.

Objective Studies have reported an increased risk of spontaneous preterm birth associated with elevated prepregnancy body mass index (BMI) among nulliparous but not multiparous women. We examined whether changes in BMI and weight between pregnancies contributed to risk of preterm birth among obese (BMI > 29 kg/m(2)) women. Study Design This study utilized maternally linked California birth records of sequential singleton births between 2007 and 2010. Preterm birth was defined as 20 to 31 or 32 to 36 weeks of gestation. BMI was examined as category change and by tertile of weight change. Primary analyses included women without diabetes or hypertensive disorders; these women were compared with those without prior preterm birth, women with preterm deliveries preceded by spontaneous preterm labor, and women without any exclusions (i.e., diabetes or hypertensive disorders). Results Analyses showed that obesity was not associated with increased risk of spontaneous preterm birth among multiparous women. Women whose BMI increased had a decreased risk of spontaneous preterm birth at 32 to 36 weeks. Change in BMI or weight between pregnancies did not substantively alter results. Conclusion Among multiparous women, obesity was associated with reduced risk of spontaneous preterm delivery. This observed association is complex and may be influenced by maternal age, gestational age, placental insufficiency, and altered immune response.

Smoking in pregnancy and risk of cancer among young children: A population-based study.

Smoking during pregnancy is a plausible risk factor for childhood cancer, yet previous studies have yielded conflicting results, and few prospective studies have been published. Data on maternal smoking were obtained from California birth certificates. We linked California birth certificates (births 2007-2011) with California Cancer Registry records for childhood cancer cases (diagnosed January 2007-September 2013) that were ages 5 or younger at diagnosis (N cases = 2,021). Controls (N = 40,356) were frequency-matched by birth year and randomly selected from birth certificate records. We used unconditional logistic regression to obtain odds ratios (OR) and 95% confidence intervals (CI) to assess the association between smoking during pregnancy and childhood cancer. We observed positive associations for gliomas (OR = 1.8, 95% CI: 1.0-3.4) and retinoblastoma (OR = 3.0, 95% CI: 1.4-6.6), particularly bilateral retinoblastoma (OR = 9.4, 95% CI 3.6-24.7) with maternal smoking in pregnancy. Maternal smoking during pregnancy may be a risk factor for retinoblastoma and certain types of childhood brain tumors.

Geographic Distribution of Healthy Resources and Adverse Pregnancy Outcomes.

Objective To determine the risk of gestational diabetes (GDM) and preeclampsia associated with various community resources. Methods An ecological study was performed in Los Angeles and Orange counties in California. Fast food restaurants, supermarkets, grocery stores, gyms, health clubs and green space were identified using Google © Maps Extractor and through the Southern California Association of Government. California Birth Certificate data was used to identify cases of GDM and preeclampsia. Unadjusted and adjusted risk ratios were calculated using negative binomial regression. Results There were 9692 cases of GDM and 6288 cases of preeclampsia corresponding to incidences of 2.5 and 1.4% respectively. The adjusted risk of GDM was reduced in zip codes with greater concentration of grocery stores [relative risk (RR) 0.95, 95% confidence interval (CI) 0.92-0.99] and supermarkets (RR 0.94, 95% CI 0.90-0.98). There were no significant relationships between preeclampsia and the concentration of fast food restaurants, grocery store, supermarkets or the amount of green space. Conclusion The distribution of community resources has a significant association with the risk of developing GDM but not preeclampsia.

Severe maternal morbidity in a large cohort of women with acute severe intrapartum hypertension

Hypertensive diseases of pregnancy are associated with severe maternal morbidity and remain common causes of maternal death. Recently, national guidelines have become available to aid in recognition and management of hypertension in pregnancy to reduce morbidity and mortality. The increased morbidity related to hypertensive disorders of pregnancy is presumed to be associated with the development of severe hypertension. However, there are few data on specific treatment or severe maternal morbidity in women with acute severe intrapartum hypertension as opposed to severe preeclampsia. The study aimed to characterize maternal morbidity associated with women with acute severe intrapartum hypertension, and to determine whether there was an association between various first-line antihypertensive agents and posttreatment blood pressure. This retrospective cohort study of women delivering between July 2012 and August 2014 at 15 hospitals participating in the California Maternal Quality Care Collaborative compared women with severe intrapartum hypertension (systolic blood pressure >160 mm Hg or diastolic blood pressure >105 mm Hg) to women without severe hypertension. Hospital Patient Discharge Data and State of California Birth Certificate Data were used. Severe maternal morbidity using the Centers for Disease Control and Prevention criteria based on International Classification of Diseases-9 codes was compared between groups. The efficacy of different antihypertensive medications in meeting the 1-hour posttreatment goal was determined. Statistical methods included distribution appropriate univariate analyses and multivariate logistic regression. There were 2252 women with acute severe intrapartum hypertension and 93,650 women without severe hypertension. Severe maternal morbidity was significantly more frequent in the women withsevere hypertension (8.8%) compared to the control women (2.3%) (P< .0001). Severe maternal morbidity rates did not increase with increasing severity of blood pressures (P= .90 for systolic and .42 for diastolic). There was no difference in severe maternal morbidity between women treated (8.6%) and women not treated (9.5%) (P= .56). Antihypertensive treatment rates were significantly higher in hospitals with a level IV neonatal intensive care unit (85.8%) compared to a level III neonatal intensive care unit (80.2%) (P < .001), and in higher-volume hospitals (84.5%) compared to lower-volume hospitals (69.1%) (P < .001). Severe maternal morbidity rates among severely hypertensive women were significantly higher in hospitals with level III neonatal intensive care unit level compared to hospitals with a level IV neonatal intensive care unit (10.6% vs 5.7%, respectively; P < .001), and significantly higher in low-delivery volume hospitals compared to high-delivery volume hospitals (15.5% vs 7.6%, respectively; P < .001). Only 53% of women treated with oral labetalol as first-line medication met the posttreatment goal of nonsevere hypertension, significantly less than those treated with intravenous hydralazine, intravenous labetalol, or oral nifedipine (68%, 71%, and 82%, respectively) (P= .001). Severe intrapartum hypertension remained untreated in 17% of women. Women with acute severe intrapartum hypertension had a significantly higher risk of severe maternal morbidity compared to women without severe hypertension. Significantly lower antihypertensive treatment rates and higher severe maternal morbidity rates were seen in lower-delivery volume hospitals.

753: Temporal and geographic patterns of home births in California 1991-2010

753: Temporal and geographic patterns of home births in California 1991-2010

Birth weight, fetal growth, and risk of pediatric rhabdomyosarcoma: an updated record linkage study in California

PurposeThe purpose of the study was to examine whether birth characteristics affect the risk of rhabdomyosarcoma (RMS) in children and adolescents younger than 19 years. MethodsA total of 722 RMS cases diagnosed at the age of 0–19 years during 1988–2011 were identified from the California Cancer Registry and matched by birth date, sex, and race to 2,888 controls using California birth records. Conditional logistic regression was used to estimate the risk of RMS associated with birth weight, gestational age, and size for gestational age. ResultsHigh birth weight (odds ratio [OR]: 1.00; 95% confidence interval [CI]: 0.78–1.29) and large for gestational age (LGA; OR: 0.94, 95% CI: 0.72–1.23) were not associated with RMS risk overall. Among non-Hispanic whites, the ORs were 1.33 for high birth weight (95% CI: 0.94–1.89) and 1.17 for LGA (95% CI: 0.78–1.75); no indications of association were observed for other racial or ethnic groups (P interaction <.10). Compared with normal gestational age, preterm (<37 weeks) and post-term (>40 weeks) babies had 16%–18% lower risks of RMS overall, after adjusting for birth weight. ConclusionsIn the largest study to date, there was an indication of association between high birth weight, LGA, and increased RMS risk among non-Hispanic white children and adolescents, but not in other racial or ethnic groups.

Gestational dating by metabolic profile at birth: a California cohort study

BackgroundAccurate gestational dating is a critical component of obstetric and newborn care. In the absence of early ultrasound, many clinicians rely on less accurate measures, such as last menstrual period or symphysis-fundal height during pregnancy, or Dubowitz scoring or the Ballard (or New Ballard) method at birth. These measures often underestimate or overestimate gestational age and can lead to misclassification of babies as born preterm, which has both short- and long-term clinical care and public health implications.ObjectiveWe sought to evaluate whether metabolic markers in newborns measured as part of routine screening for treatable inborn errors of metabolism can be used to develop a population-level metabolic gestational dating algorithm that is robust despite intrauterine growth restriction and can be used when fetal ultrasound dating is not available. We focused specifically on the ability of these markers to differentiate preterm births (PTBs) (<37 weeks) from term births and to assign a specific gestational age in the PTB group.Study DesignWe evaluated a cohort of 729,503 singleton newborns with a California birth in 2005 through 2011 who had routine newborn metabolic screening and fetal ultrasound dating at 11–20 weeks’ gestation. Using training and testing subsets (divided in a ratio of 3:1) we evaluated the association among PTB, target newborn characteristics, acylcarnitines, amino acids, thyroid-stimulating hormone, 17-hydroxyprogesterone, and galactose-1-phosphate-uridyl-transferase. We used multivariate backward stepwise regression to test for associations and linear discriminate analyses to create a linear function for PTB and to assign a specific week of gestation. We used sensitivity, specificity, and positive predictive value to evaluate the performance of linear functions.ResultsAlong with birthweight and infant age at test, we included 35 of the 51 metabolic markers measured in the final multivariate model comparing PTBs and term births. Using a linear discriminate analyses-derived linear function, we were able to sort PTBs and term births accurately with sensitivities and specificities of ≥95% in both the training and testing subsets. Assignment of a specific week of gestation in those identified as PTBs resulted in the correct assignment of week ±2 weeks in 89.8% of all newborns in the training and 91.7% of those in the testing subset. When PTB rates were modeled using the metabolic dating algorithm compared to fetal ultrasound, PTB rates were 7.15% vs 6.11% in the training subset and 7.31% vs 6.25% in the testing subset.ConclusionWhen considered in combination with birthweight and hours of age at test, metabolic profile evaluated within 8 days of birth appears to be a useful measure of PTB and, among those born preterm, of specific week of gestation ±2 weeks. Dating by metabolic profile may be useful in instances where there is no fetal ultrasound due to lack of availability or late entry into care.

Socio-Economic Status and Childhood Leukemia in California

Objective: To investigate the association between individual- and community-level socio-economic status (SES) and childhood leukemia, particularly its subtypes: acute lymphoblastic leukemia (ALL) and acute myeloid leukemia (AML). Study design: We conducted a large case-control registry-based study in California. Methods: Information on 5788 cases and 5788 controls was obtained by linking California cancer and birth registries. We evaluated relative risk of childhood leukemia by community- (census-based) and individual-level SES measures (parental education and source of payment for delivery) using conditional logistic regression. Results: Children in higher census-based SES categories had a tendency toward slightly decreased risk of total childhood leukemia and ALL compared to children of the lowest SES. Compared to < 12 years of school, 13 and more years of parental education were associated with slightly decreased risk of total childhood leukemia, ALL and AML; however, confidence intervals were imprecise. Source of payment for delivery was not associated with either childhood leukemia nor with its subtypes. Conclusion: We found little evidence to support the suggestion that SES is associated with risk of childhood leukemia or either major subtype. It is likely that results of many previous studies that found an association between childhood leukemia and SES were influenced by selection or ecological bias.

Exposure To Multiple Sources And Components Of Air Pollution And Low Birth Weight In California, 2001-2008.

Introduction This study investigated the associations between low birth weight (LBW, = 37 gestational weeks) and air pollution by source and composition in California, over the period 2001-2008. Methods Complementary exposure models were used: an empirical Bayesian kriging model for the interpolation of ambient pollutant measurement results, a source-oriented chemical transport model (using California emission inventories) that estimated fine and ultrafine particulate matter (PM) concentrations (4 km* 4 km) by source and composition, a line-source roadway dispersion model at fine resolution, and traffic index estimates. Birth weight was obtained from the California birth certificate records. Five controls per LBW case were randomly selected (without matching or stratification). The resulting case-control datasets were analyzed by logistic regression with random effect per hospital, using generalized additive mixed models adjusted for race/ethnicity, education, maternal age and household income. Results In total 72,632 LBW cases were included. LBW was positively associated with interpolated measurements of ozone but not total fine PM or nitrogen dioxide. No significant association was observed between term LBW and primary PM from all sources grouped together. However, LBW risk was positively associated with primary PM emitted by on-road gasoline and diesel or by commercial meat cooking sources. Primary PM from wood burning was inversely associated with LBW. Positive associations (respectively significant and close to significant) were observed for secondary organic aerosols and nitrates. LBW was positively associated with ultrafine particle numbers modeled with the line-source roadway dispersion model, and with traffic density. Discussion This large study based on complementary exposure metrics points to primary pollution sources (traffic and commercial meat cooking) but also to secondary pollutants as risk factors for LBW.

Effect of time of birth on maternal morbidity during childbirth hospitalization in California

This observational study aimed to determine the relationship between time of birth and maternal morbidity during childbirth hospitalization. Composite maternal morbidities were determined using International Classification of Diseases, Ninth Revision, Clinical Modification and vital records codes, using linked hospital discharge and vital records data for 1,475,593 singleton births in California from 2005 through 2007. Time of birth, day of week, and sociodemographic, obstetric, and hospital volume risk factors were estimated using mixed effects logistic regression models. The odds for pelvic morbidity were lowest between 11 PM-7 AM compared to other time periods and the reference value of 7-11 AM. The odds for pelvic morbidity peaked between 11 AM-7 PM (adjusted odds ratio [AOR], 1101-1500 = 1.07; 95% confidence interval [CI], 1.06-1.09; 1501-1900 = 1.08; 95% CI, 1.06-1.10). Odds for severe morbidity were higher between 11 PM-7 AM (AOR, 2301-0300 = 1.31; 95% CI, 1.21-1.41; 0301-0700 = 1.30; 95% CI, 1.20-1.41) compared to other time periods. The adjusted odds were not statistically significant for weekend birth on pelvic morbidity (AOR, Saturday = 1.00; 95% CI, 0.98-1.02]; Sunday = 1.01; 95% CI, 0.99-1.03) or severe morbidity (AOR, Saturday = 1.09; 95% CI, 1.00-1.18; Sunday = 1.03; 95% CI, 0.94-1.13). Cesarean birth, hypertensive disorders, birthweight, and sociodemographic factors that include age, race, ethnicity, and insurance status were also significantly associated with severe morbidity. Even after controlling for sociodemographic factors and known risks such as cesarean birth and pregnancy complications such as hypertensive disorders, birth between 11 PM-7 AM is a significant independent risk factor for severe maternal morbidity.

Heightened risk of preterm birth and growth restriction after a first-born son

PurposeIn Scandinavia, delivery of a first-born son elevates the risk of preterm delivery and intrauterine growth restriction of the next-born infant. External validity of these results remains unclear. We test this hypothesis for preterm delivery and growth restriction using the linked California birth cohort file. We examined the hypothesis separately by race and/or ethnicity. MethodsWe retrieved data on 2,852,976 births to 1,426,488 mothers with at least two live births. Our within-mother tests applied Cox proportional hazards (preterm delivery, defined as less than 37 weeks gestation) and linear regression models (birth weight for gestational age percentiles). ResultsFor non-Hispanic whites, Hispanics, Asians, and American Indian and/or Alaska Natives, analyses indicate heightened risk of preterm delivery and growth restriction after a first-born male. The race-specific hazard ratios for preterm delivery range from 1.07 to 1.18. Regression coefficients for birth weight for gestational age percentile range from −0.73 to −1.49. The 95% confidence intervals for all these estimates do not contain the null. By contrast, we could not reject the null for non-Hispanic black mothers. ConclusionsWhereas California findings generally support those from Scandinavia, the null results among non-Hispanic black mothers suggest that we do not detect adverse outcomes after a first-born male in all racial and/or ethnic groups.

Heme oxygenase-1 promoter polymorphisms and risk of spina bifida.

Spina bifida is the most common form of neural tube defects (NTDs). Etiologies of NTDs are multifactorial, and oxidative stress is believed to play a key role in NTD development. Heme oxygenase (HO), the rate-limiting enzyme in heme degradation, has multiple protective properties including mediating antioxidant processes, making it an ideal candidate for study. The inducible HO isoform (HO-1) has two functional genetic polymorphisms: (GT)n dinucleotide repeats and A(-413)T SNP (rs2071746), both of which can affect its promoter activity. However, no study has investigated a possible association between HO-1 genetic polymorphisms and risk of NTDs. This case-control study included 152 spina bifida cases (all myelomeningoceles) and 148 non-malformed controls obtained from the California Birth Defects Monitoring Program reflecting births during 1990 to 1999. Genetic polymorphisms were determined by polymerase chain reaction and amplified fragment length polymorphisms/restriction fragment length polymorphisms using genomic DNA extracted from archived newborn blood spots. Genotype and haplotype frequencies of two HO-1 promoter polymorphisms between cases and controls were compared. For (GT)n dinucleotide repeat lengths and the A(-413)T SNP, no significant differences in allele frequencies or genotypes were found. Linkage disequilibrium was observed between the HO-1 polymorphisms (D': 0.833); however, haplotype analyses did not show increased risk of spina bifida overall or by race/ethnicity. Although, an association was not found between HO-1 polymorphisms and risk of spina bifida, we speculate that the combined effect of low HO-1 expression and exposures to known environmental oxidative stressors (low folate status or diabetes), may overwhelm antioxidant defenses and increase risk of NTDs and warrants further study.

STD and Abortion Prevalence in Adolescent Mothers With Histories of Childhood Protection Involvement.

Early sexual debut and unprotected sexual activity place adolescents at risk of adverse sexual health outcomes. Adolescents involved with child protective services (CPS) may be a particularly vulnerable population. California birth records for 86,946 adolescents who became first-time mothers in 2008-2010 were probabilistically linked to statewide CPS records from 1998 and later. The prevalence of STDs at birth and of abortion history were explored by preconception CPS involvement. Generalized linear models, adjusted for health, socioeconomic and demographic characteristics, were used to assess correlates of current STDs and history of abortion. At the time they gave birth, 1% of adolescents had a documented STD, and 5% reported a previous abortion. After adjustment for other characteristics, CPS involvement was associated with a significantly elevated prevalence both of STDs (relative risk, 1.2) and of previous abortion (1.4). Other characteristics also were associated with both outcomes, but not always in the same direction. For example, delaying prenatal care until after the first trimester or getting none at all was associated with an increased prevalence of STDs (1.3), but a reduced prevalence of abortion (0.8-0.9); having public insurance coverage for the birth was associated with a reduced STD prevalence (0.9) and an elevated abortion history prevalence (1.2). To assess whether adolescents with a history of CPS involvement need targeted sexual health interventions, further research is needed on the mechanisms that underlie associations between CPS involvement and adverse sexual health outcomes.

Auspicious birth dates among Chinese in California

The number eight is considered lucky in Chinese culture, e.g. the Beijing Olympics began at 8:08 pm on 8/8/2008. Given the potential for discretion in selecting particular dates of labor induction or scheduled Cesarean section (C-section), we consider whether Chinese-American births in California occur disproportionately on the 8th, 18th, or 28th day of the month. We find 2.3% “too many” Chinese births on these auspicious birth dates, whereas Whites show no corresponding increase. The increase in Chinese births is driven by higher parity C-sections: the number of repeat C-sections is 6% “too high” on auspicious birth dates. Sons born to Chinese parents account for the entire increase; daughter deliveries do not seem to be timed to achieve “lucky” birth dates. We also find avoidance of repeat C-section deliveries on the 4th, 14th, and 24th of the month, considered unlucky in Chinese culture. Finally, we replicate earlier work finding that Friday the 13th delivery dates are avoided and document a particularly large decrease among Chinese. For Whites and Chinese in California, mothers with higher levels of education are particularly likely to avoid delivering on the 13th.