PubMed Health⌕ Search

Biomedical subjects

D M Keith

Publications and source records attributed to D M Keith.

15 recordsLinked to original sources
PubMed2001

Maternal race/ethnicity and twinning rates in the United States, 1989-1991.

OBJECTIVE: To utilize United States birth certificate data (years 1989-1991) to examine the effects of race/ethnicity on twinning rates. STUDY DESIGN: We used a database of birth certificate data for the United States (years 1989-1991) available on CD-ROM from the United States National Center for Health Statistics. This linked birth/infant death data set included a total of 12,036,234 birth records, of which 279,073 were twins. Excluded from the analysis were 15,086 twin birth records (5.4%) based upon previously described exclusion criteria. Statistical analysis included a series of univariate analyses to determine the rates of twinning between different racial/ethnic groups correlated with maternal age, education, marital status and place of birth. Comparisons were analyzed using the chi 2 test, with significance at P < .05. RESULTS: The overall twinning rate was 2.26%, with the lowest rate observed in the group denoted non-Hispanic other (1.67%) and highest among non-Hispanic blacks (2.69%). Twinning rates within various groups representing Hispanics ranged from 1.76% to 2.08%. The twinning rate was significantly higher among U.S.-born as compared to non-U.S.-born women (2.34% vs. 1.88%, P < .005) except for Puerto Ricans, Cubans and Central/South Americans, for whom the reverse was true. Women aged 35-39 had the highest twinning rate (3.05%), whereas women aged 15-19 had the lowest; that trend persisted in all racial/ethnic groups. The study showed a nonsignificant relationship between marital status or education and twinning rate. CONCLUSION: Race/ethnicity studies can be useful in designing programs that may maximize health outcomes of twins in a racially diverse population.

Adult↗
PubMed2000

Zygosity of twins: is it time for a new terminology?

The term zygosity reflects the origin of twins--when twins are monozygotic, they are derived from a single fertilized ovum; when twins are dizygotic--the come from two fertilized ova. Zygosity assessment seemed straightforward 50 years ago. Currently, as more information and more technology becomes available, zygosity testing becomes a real problem. It is important to realize the importance of correct zygosity testing not only in the antepartum care of the pregnant mother, but more importantly--during the whole lifetime of twin individuals. This paper discusses revolving around zygosity, methods of assessment, their limitations and proposes new terminology which incorporates the recent knowledge about early human development.

Algorithms↗
PubMed1999

Projections of population-based twinning rates through the year 2100.

OBJECTIVE: To present the first compilation of population-based twinning rates published after the year 1990 and to project population-based twinning rates through the year 2100. STUDY DESIGN: We searched the Internet-based MEDLINE database for articles published after 1990 in which population-based twinning rates were described. We used population-based data from national statistical authorities from Australia, Austria, Canada, Finland, Hong Kong, Israel, Japan, Norway, Singapore and Sweden, published by Y. Imaizumi in a recent article. U.S. figures were based on data from the National Center for Health Statistics. Annual growth rates of twinning were calculated and graphed, making the assumption that these rates would remain constant throughout the next century. RESULTS: Our report presents the most recent population-based twinning rates. When projected through the year 2015, twinning rates reach figures that could best be described as derived from a Jules Verne novel: Sweden, in this model, would have four times more twin than singleton births. CONCLUSION: We strongly suggest that physicians reexamine their patterns of prescribing ovulation-inducing agents, which carry a greatly increased risk of multiple pregnancy.

Adult↗
PubMed1988

The Northwestern University Twin Study. V: Twin deliveries at Prentice Women's Hospital and Maternity Center, 1978-83.

Two hundred fifty-one twin deliveries between January 1, 1978 and June 30, 1983 at Prentice Women's Hospital and Maternity Center were reviewed. Cases were excluded if birth weight was less than 500 g, if gestational age was less than 26 weeks or if an antenatal fetal demise had occurred. Maternal demographic characteristics, delivery data and infant characteristics are described. The effect of providing care to a high-risk population of mothers in whom approximately 60% either deliver their infants preterm or with a birth weight of less than 2,500 g is discussed in terms of costs of care.

Adolescent↗
PubMed1988

The Northwestern University Triplet Study. I: Overview of the international literature.

The international literature on triplet births is surveyed. No definitive work on triplet gestations exists. The relatively few articles on this subject are divided into three categories: 1) national data; 2) local, regional or hospital series; 3) case reports. Clinical concerns, such as prematurity, low birth weight, bed rest, and tocolysis, are discussed with specific reference to literature citations.

Bed Rest↗
PubMed1988

The Northwestern University Triplet Study. II: Fourteen triplet pregnancies delivered between 1981 and 1986.

Fourteen triplet deliveries conducted between 1 January 1981 and 30 June 1986 at the principal teaching hospitals of Northwestern University Medical School are reviewed. Maternal demographic characteristics are listed, as are the obstetric outcomes, including mode of delivery, and the fetal outcome. The recent literature of triplet delivery is reviewed. The rate of triplet delivery in our study was 0.37 per 1,000 live births. About two-thirds of the pregnancies resulted from the use of fertility-inducing agents. Ultrasonic confirmation was available in all cases. The majority of women were delivered by cesarean section (85%). No consistent pattern of presentation was seen. The mean weight of all 42 infants was 1,779 g (+/- 594). Unlike-sex triplets accounted for most of the sets (77%). The mean 5-min Apgar score of all infants was 9 and had no association with the order of deliveries. The weight differences by sex regardless of birth order were clinically insignificant. Neonatal mortality was 2.3%.

Adult↗
PubMed1988

How Washington State doctors battled it and won.

Mandatory medical assignment bills have been presented to the legislatures of 16 states since 1985, when a bill passed in Massachusetts tied acceptance of assignment to medical licensure, In November 1987, an initiative appeared on the Washington State voter's ballot asking that it be considered a consumer protection violation for physicians to charge more than Medicare's "reasonable" fee. This was the first time that the issue was presented to the registered voters of any state. This article details the way in which the Washington State Medical Association combatted the initiative and turned around an electorate that was 68% in favor, in August, to a final ballot of 63.9% opposed.

Consumer Advocacy↗
PubMed1986

The Nordic contribution to the English language twin literature.

This project was inspired by the extensive contribution of Nordic researchers to the English language twin literature. The purpose of the study was to compile a source bibliography of twin literature written at Nordic institutions. The bibliography compiled as a supplement for this paper provides as complete a survey as is possible to obtain in the United States. Our search began with a Medline Computer data base. To make our survey more complete, we cross-referenced and added to this using the Index Medicus, the National Institute of Mental Health Bibliography, Excerpta Medica, specific article references, references provided by Nordic university libraries and Gedda's Estudio dei Gemelli. The full bibliography of 313 references is available at no cost from the Center for the study of multiple Birth, Rm. 476, 333 E. Superior, Chicago, Ill. 60611, U.S.A.

Bibliographies as Topic↗
PubMed1977

Medical equipment costs: those you see and those you pay.

A review of life cycle and operation support costestimating capabilities in the health care industry shows few models that discuss total ownership costs for major items, let alone for some expensive minor ones. As yet, no data collection system exists wthat will provide total costs of acquisitions. There is a clear need for the health industry to focus greater attention on life cycle costs of medical equipment. This is particularly pertinent to those physicians responsible for medical equipment acquisition programs. The industry must evaluate the impact of life cycle costs and make such evaluations available to decision makers. The purpose of this paper is to improve the visibility and accuracy of cost estimating by examining the elements of life cycle costs.

Costs and Cost Analysis↗
PubMed1976

Leukemia in twins: antenatal and postnatal factors.

Two factors emerged from a search for obstetric phenomena that might explain concordance of leukemia in both members of a twin pair within days or months of each other: antenatal exposure to ionizing radiation; and antenatal cojoined intrauterine circulation. In addition, antenatal tumor metastasis and chromosomal changes, antenatal or postnatal, may be contributory. Continued observation of reports should be carried out.

Adolescent↗
PubMedDate not supplied

Utilization management in hospital clinical laboratories: a local analysis.

As hospital clinical laboratories position themselves for increasing involvement in managed care plans and for dealing with increasing cost containment, laboratory managers need to produce and assess data on the use of their testing services. The purpose of this study was to answer questions about the relationship between several dependent variables and the laboratory utilization management (UM) processes currently in place. An investigator-designed questionnaire was used to gather data on hospital bed size, availability of pathologists, involvement in managed care plans, and the types of laboratory information systems in use. The questionnaire was sent to the managers of all acute care hospital laboratories in the greater Houston metropolitan area. Although the total number of responses was small, the results showed that there is very little UM activity in Houston acute care hospital laboratories. This lack of sophisticated UM procedures may be consistent with the immature and evolving managed care environment in Houston.

Clinical Laboratory Information Systems↗
PubMedDate not supplied

Multiple gestation: reflections on epidemiology, causes, and consequences.

Multiple births (of all orders) increased in epidemic proportions in the years 1971-1997. Twins increased 53%, 32%, 31%, and 83% in white, Afro-American, Native American and Mexican American women, respectively. Triplet, quadruplet, and quintuplet+ births increased >400%, >1,100%, and >500%, respectively, in the same years. The principal causes of these changes are related to the increasing age of the maternal cohort and an increasing incidence of fertility-inhibiting diseases and conditions in association with advancing maternal age. Major immediate consequences of these changes include disproportionately large numbers of infants born at <33 weeks' gestation (1.7% for singletons vs. 41.2% for triplets) and at <1,500 g birth weight (1.1% for singletons vs. 31.9% for triplets). Additional short-term consequences include an almost 2,000% increase in infant deaths (per 1,000 live births) among triplets compared with singletons (190.4 vs. 11.2). Long-term risks include a 300% increase in the relative risk of handicap in triplets compared with singletons (2.9 vs. 1.0), and a 650% increase in the rate of cerebral palsy per 1,000 live births in triplets compared with singletons (26.6 vs. 1.6). Peripartum costs relate to prematurity rather than plurality, as do lifetime survivorship costs, which relate to morbidities and subsequent health-related problems.

Female↗