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Biomedical subjects

Louis Keith

Publications and source records attributed to Louis Keith.

6 recordsLinked to original sources
PubMed2004

Risks in triplet pregnancy: advanced maternal age, premature rupture of membranes and risk estimates of mortality.

OBJECTIVE: To investigate the impact of older maternal age on the risk of mortality associated with premature rupture of membranes (PROM) among triplets. STUDY DESIGN: A retrospective, cohort study was performed on triplet deliveries in the United States that occurred in the period perinatal and 1995-1998. The study group comprised mothers aged > or =40 years (older mothers), who were compared to mothers aged 30-39 (mature mothers), 20-29 (younger mothers) and mothers <20 (teenagers). We computed risks of mortality associated with PROM within each maternal age category using generalized estimating equations to take into account both intracluster and intercluster sources of variation. RESULTS: The risk of stillbirth and of neonatal and perinatal mortality related to PROM was highest among teenagers. In all circumstances, the risk of both intrauterine and extrauterine death resulting from PROM diminished progressively with increasing maternal age until age 40 and beyond, at which point the risk rose once more and produced a U shape. PROM triplets of older mothers had apparently higher mortality indices than did those of younger and mature mothers, although the risk difference did not show statistical significance for any of the mortality indices. Similarly, the proportion of preventable deaths if PROM could be averted demonstrated a U-shape, consistent with that of risk estimates. CONCLUSION: Premature rupture of membranes was associated with an increase risk of perinatal and infant mortality among triplets. Although older mothers demonstrated higher risk levels for all mortality indices in comparison to younger and mature mothers, our findings did not reach statistical significance.

Adolescent↗
PubMed2003

DNA stability and schizophrenia in twins.

The goal of these experiments was to understand DNA changes relevant to schizophrenia. This work compared DNA of monozygotic (MZ) twins surrounding (CAG)(n) repeating sequences, and characterized the relationship between fragile sites and schizophrenia. Twelve twin-pairs, previously classified as MZ and 18 unrelated sib-pairs, from seven families were studied. Eight twin-pairs were affected by schizophrenia, four concordantly and four discordantly. DNA comparisons were made using profiles of electrophoretic size fractionations of PCR amplified (CAG)(n) containing genomic fragments. These profiles were generated by a new method, developed by us, called targeted genomic differential display (TGDD). Surprisingly, the number of peak profile differences in MZ twin-pairs discordant for schizophrenia was greater than the concordantly ill twins and the well twins and, in some cases, overlapped the range of sib-pairs. These results might mean that some twins were not MZ but it was not possible to definitively test these samples for zygosity. Alternatively, the results might be explained as an increased mutation rate (or genomic instability) around (CAG)(n) sites in individuals afflicted with schizophrenia. Also, we uncovered an association of schizophrenia (i.e., a linkage of chromosomal abnormalities and gene localizations) with fragile sites spread throughout the genome (chi(2), P = 0.001). Furthermore, it appears that an increasing number of genes linked to schizophrenia are associated with (CAG)(n) sequences. Fragile sites and (CAG)(n) repeat sequences are known to be unstable. We speculate the association of genomic instability with schizophrenia accounts for seemingly disparate biological and environmental factors that influence disease occurrence.

Adolescent↗
PubMed2003

Iatrogenic multiple pregnancies. Do they complicate perinatal care?

This review addresses questions related to medicosocial concerns surrounding the care of women with multiple births and their infants. Relevant articles and texts on twin and triplet pregnancies were reviewed. Population-based data were selected for inclusion whenever possible. Relevant tables were simplified from original sources. The review clarifies obstetric and perinatal questions in a manner that is helpful to clinicians and their patients.

Female↗
PubMedDate not supplied

Triplet pregnancies and their aftermaths. Part I: Basic considerations.

Until recently, triplets were an infrequent occurrence. With the development of ovulation-inducing medications and then assisted reproductive technology (ART), the triplet birth rate in maternal age ranges over 24 years has multiplied three- to fiftyfold. The first review of the clinical aspects of triplet pregnancies was published in 1988. Since then, more data reported on such births have revealed a consistent triad of preterm delivery, low birth weight, and very low birth weight, plus increased maternal risks. This article details comparative risks to mothers and children using population-based data comparing differential outcomes in singletons, twins, and triplets; an extensive review of recent triplet publications is provided in the references.

Birth Rate↗
PubMedDate not supplied

Triplet pregnancies and their aftermaths II. Risks of older mothers and plurality.

There is no literature that accurately reports the risks inherent to the woman over age 40 who carries a triplet pregnancy. Extrapolating the singleton literature does not provide solid evidence, since risks are described variously by different authors and may relate to maternal age or parity as independent factors, which affect both maternal and fetal outcome data. On the other hand, recent population-based surveys strongly suggest that plurality is a more important risk factor than maternal age, for it affects both maternal and fetal outcomes.

Adult↗