The association between parity and selected structural birth defects

BACKGROUND: Parity is a risk factor in neonatal morbidity and mortality. This dissertation examined the association between first births and selected birth defects. The first aim was to assess the risk of 66 birth defects among first births and third or greater births. The second aim was to determine if maternal race, maternal age, infant sex or infant birth weight modify the association between first births and selected birth defects. METHODS: The Texas Birth Defects Registry provided data for 1999-2009. For the first aim, odds ratios were calculated for each birth defect. For the second aim, analysis was restricted to the ten birth defects significantly associated with first births. Stratified analyses were conducted and interaction terms were added to logistic regression models to assess whether differences in the odds ratios for the effect of first birth were statistically significant across strata. RESULTS: Findings for the first aim showed that first births had significantly increased odds of having an infant with 24 of the 66 birth defects. Third or greater births had significantly increased odds of having four of the 66 birth defects. For the second aim, a number of significant effect modifiers were observed. For patent ductus arteriosis, obstructive urinary defects and gastroschisis, the effect of first births was significantly modified by black or U.S.-born Hispanic mothers. The effect of first birth was also significantly modified among mothers ≥30 years for mitral valve insufficiency, atrial septal defect and congenital hip dislocation. The effect of first births was significantly modified among infants with low birth weight for hypospadias, congenital hip dislocation and gastroschisis. CONCLUSIONS: First births were associated with an elevated risk of 24 categories of birth defects. For some of the birth defects studied, the effect of first birth is modified by maternal age, maternal race and low birth weight. Knowledge of the increased risk for birth defects among women having their first birth allows physicians and midwives to provide better patient care and spur further research into the etiology of associated birth defects. This knowledge may bring about interventions prior to conception in populations most likely to conceive.^

The effects of adequacy and content of prenatal care on birth outcomes in a high -risk Missouri population

The purpose of this observational study was investigation of the relationship between quantitative adequacy of prenatal care, specific prenatal care content and pregnancy outcome in a high risk Missouri population. A sample of 1484 women from three Missouri regions known to have high rates of low birth weight, infant mortality, and inadequate prenatal care rates participated in structured post-partum interviews. Approximately one-half of the sample had received adequate prenatal care and the other half inadequate prenatal care as determined by an index utilized by the Missouri Department of Health.^ Prenatal care content was assessed by reports of prenatal education in six different areas: Diet, smoking, alcohol, drug, preterm labor counseling, and advice on when to call the health provider if preterm labor was suspected by the woman. Low birth weight, in both term and preterm infants, were the two birth outcomes examined. A variety of maternal socio-demographic variables were also considered.^ The results of this study suggest that specific educational content, delivered during prenatal care, may have lessen the risk of giving birth to a preterm-low birth weight infant. Prenatal education for recognition of preterm labor, and advice on when to call the health provider if preterm labor was suspected were found to be associated with a decreased risk of preterm delivery. Specific educational content was not, however, associated with risk of term-low weight birth nor was quantitative adequacy of care associated with the risk of either term- or preterm-low birth weight.^ These findings reinforce a body of literature which stresses the importance of appropriate prenatal care in preventing preterm low birth weight. Additionally, the findings suggest interventions that may be specifically effective for prematurity prevention. ^