Risk for birth defects among premature infants: a population-based study.

OBJECTIVE: To investigate the relationship between prematurity and birth defects. STUDY DESIGN: In a population-based cohort study, infants with birth defects were ascertained through the Metropolitan Atlanta Congenital Defects Program, a surveillance system with active methods of ascertainment. Gestational age data were obtained from birth certificates of liveborn, singleton infants with and without birth defects born in the 5-county metropolitan Atlanta area. RESULTS: Among 264,392 infants with known gestational ages born between 1989 and 1995, 7738 were identified as having birth defects (2.93%). Premature infants (<37 weeks' gestation) were more than two times as likely to have birth defects than term infants (37-41 weeks) (risk ratio = 2.43; 95% CI 2.30-2.56). This relationship was evident for several categories of birth defects. The rate of birth defects varied by gestational age categories, with the highest risk in the 29- to 32-week gestational age category (risk ratio = 3.37). CONCLUSIONS: The risk for birth defects is increased in premature infants. Awareness of this relationship is important for clinicians caring for premature infants. The morbidity and mortality associated with a particular defect may be significantly altered by the presence of prematurity. Further study of this association may provide insight into the etiology of these relatively common problems.

The correspondence of vocal tract resonance with volumes obtained from magnetic resonance images.

The increasing availability of magnetic resonance imaging (MRI) as a research, and even clinical, tool in speech production makes possible a wide range of quantitative methods in vocal tract measurement. In these initial stages of application, it is essential that the limits of the method be identified. The present investigation was designed to apply the techniques of digital image analysis and volumetric measurement to MRIs obtained for the vocal tract during production of continuant speech sounds, and to apply these measures to a well-established and thoroughly tested model of acoustic transmission (Stevens & House, 1955). The results demonstrated that, although there were several sources of relatively large error and measurement bias, the vocal tract volumes obtained from MRIs were significantly predictive of vocal tract resonance frequencies. These results are discussed with respect to limits and potential for future application of MRI to speech production research.

Fetal brain disruption sequence.

The fetal brain disruption sequence is a recognizable pattern of defects that includes moderate to profound microcephaly, overlapping sutures, occipital bone prominence, and scalp rugae. The condition is postulated to arise from partial brain disruption during the second or third trimester with subsequent fetal skull collapse resulting from decreased intracranial hydrostatic pressure. Proposed causes include prenatal viral or parasitic infections and vascular disruptions. We report seven infants with the fetal brain disruption sequence. Two of these patients died. A changing phenotype with time was seen in three. Recognition of this phenotype is critical because the condition has a uniformly poor prognosis for infants but the recurrence risk in future pregnancies is low.