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Biomedical subjects

G R Alexander

Publications and source records attributed to G R Alexander.

At least 73 records · Page 4Linked to original sources
PubMed1991

Prenatal care and prematurity: is there an association in uncomplicated pregnancies?

A retrospective investigation examined patterns of use of prenatal care and pregnancy outcomes (low birthweight and preterm births) in 6176 pregnancies without antepartum medical complications. Prenatal care use patterns differed significantly by mother's age, marital status, race, education, method of payment, and gravidity. By controlling for these differences through a logistic regression procedure, results showed that prenatal care was associated with significant reductions in the number of infants who were delivered preterm or had low birthweight. Fewer very low-birthweight (less than 1500 g) infants were among the preterm infants delivered to mothers with prenatal care compared with women who received no prenatal care. These data suggest that significant improvements in pregnancy outcomes are seen among women who use prenatal care, and these benefits occur in the absence of antepartum complications.

Adolescent↗
PubMed1991

Preterm birth prevention: an evaluation of programs in the United States.

During the last decade several programs were established to prevent the onset of preterm labor and facilitate its early identification and treatment. Although these prevention programs shared a similar goal, they varied in their primary outcome focus, target populations, study designs, and specific intervention components. Their initial reports were promising; however, subsequent evaluations of efforts in the United States produced mixed results. The current literature is suggestive of the benefits of programs to prevent preterm labor and delivery, but methodologic differences among them and deficiencies in the reported evaluations have rendered a final verdict equivocal. Many studies using historical or geographic controls found positive results, whereas randomized, controlled trials did not find a significant impact. Positive results were found in studies using low-risk populations, but investigations of high-risk patients noted little effect. Together with continued research on the factors that underlie the onset of labor, additional assessment of these programs and their individual intervention components appears to be necessary.

Bed Rest↗
PubMed1991

Source of bias in prenatal care utilization indices: implications for evaluating the Medicaid expansion.

BACKGROUND: Recent expansions in eligibility for coverage of prenatal care services by the Medicaid program reflect national initiatives to improve pregnancy outcomes. This study investigates the potential impact that completeness of reporting of prenatal care and gestational age variables and strategies to impute missing data may have on evaluations of the Medicaid expansion. METHODS: This study, examining 15 years of vital record data from a single state and comparing 1 year of data from four mid-Atlantic states, selected single live births to resident mothers for analyses. The "day 15" and the "preceding case" methods were used to impute missing gestational age data. RESULTS: Considerable temporal and geographic variation was detected in completeness of reporting of variables used to construct prenatal care indices. After imputing values for cases with missing data, the proportion of cases for which adequacy of prenatal care utilization could not be determined ranged from 3% to 24% among the states investigated. For those cases where gestational age data could be imputed, the distribution of prenatal care utilization was not markedly disparate from those cases with complete reporting of gestational age. CONCLUSIONS: The results indicate that variations in reporting, decisions regarding the treatment of missing data, and the choice of the denominator can alter prenatal care utilization percentages and have implications for evaluations of the impact of the recent Medicaid expansion on prenatal care utilization.

Bias↗
PubMed1991

Gestational age assessment in preterm neonates weighing less than 1500 grams.

Postnatal assessment of gestational age in preterm neonates traditionally has been performed using the methods of Dubowitz and Ballard. This study was designed to determine the accuracy of these methods in a sample of very low birth weight preterm neonates. Dubowitz and Ballard examinations were done on 110 preterm neonates within the first 72 hours of life by a neonatologist masked to the gestational age assessed antenatally. Mean birth weight was 1066 +/- 256 g (SD). These data were compared with gestational age assessments using last menstrual period and best obstetric estimate calculated by an obstetrician unaware of the neonatal examination. Mean gestational age using last menstrual period was 28.3 +/- 2.9 weeks. Mean differences between last menstrual period and Dubowitz/Ballard were -2.8 +/- 2.1 weeks and -2.6 +/- 2.2 weeks, respectively. Results using best obstetric estimate were similar. An ophthalmologist examined lens vessels of 89 neonates. A similar pattern toward overestimation of gestational age interval by Dubowitz/Ballard was seen at each lens vessel grade. The Dubowitz and Ballard examinations are inaccurate methods of assessing gestational age in preterm neonates with birth weights less than 1500 g.

Birth Weight↗
PubMed1990

Anamnestic pregnancy risk assessment.

Based on data obtained from the 1984-1985 Guadeloupean Perinatal Audit, a pregnancy risk scoring system was developed using maternal demographic, socioeconomic, obstetric history and risk characteristics recorded at the first prenatal visit. Various combinations of risk factors were identified for four distinct pregnancy outcomes (perinatal mortality, low birth weight, preterm delivery and intra-uterine growth retardation). The findings emphasize the importance of developing risk assessments for discrete pregnancy outcomes within specific populations.

Adult↗
PubMed1990

Racial differences in pregnancy duration and its implications for perinatal care.

The average length of gestation is about 5 days shorter in black populations than in white populations. Although some of this difference is accounted for by higher preterm delivery rates in blacks, the most common gestational week of delivery at term is the 39th in black populations, the 40th in white. Black gestational age specific neonatal mortality is lower than that of whites until the 37th week of gestation, but higher thereafter. These observations suggest the hypothesis that complications of postmaturity occur sooner in black fetuses. If this hypothesis is confirmed, antepartum surveillance for signs of fetal compromise should be initiated earlier in gestation in black parturients, perhaps by setting the estimated date of confinement at 275 days after the LMP, rather than the conventional 280 days.

Black People↗
PubMed1990

Gross motor milestones in preterm infants: correction for degree of prematurity.

The age of gross motor milestone attainment and how it is affected by degree of prematurity at delivery were studied in 100 high-risk, preterm (less than 32 weeks) infants with normal motor outcome. We calculated the mean age of attainment for each milestone on the basis of chronologic age from the date of delivery and term age equivalent, correcting for degree of preterm delivery. Half of these preterm infants were male; 70% were black. The infants were compared with a population of normal infants born at term. In this very preterm population, there were no consistent sex differences, but black infants generally attained motor milestones before white infants. For each motor milestone, regardless of gender or race, the mean term age equivalents of attainment for very preterm infants closely approximated the mean ages of milestone attainment for term infants, whereas the mean chronologic ages were delayed 2 or 3 months. We conclude that very preterm infants can be expected to demonstrate sequential gross motor development at a rate expected for degree of prematurity. Chronologic age is not a valid measurement scale to use in determining motor delay in very preterm infants.

Aging↗
PubMed1990

A cross-sectional study of herpes simplex virus types 1 and 2 in college students: occurrence and determinants of infection.

Occurrence rates and determinants of infection with herpes simplex virus types 1 and 2 (HSV-1 and HSV-2) were measured in first- and fourth-year undergraduate students at a state university. This cross-sectional multistage probability sample survey included sociodemographic characteristics, sexual behavior patterns, disease history, and HSV type-specific antibody status. The prevalence of HSV-1 antibody was 37.2% in freshmen and 46.1% in fourth-year students; that for HSV-2 antibody was 0.4% and 4.3%, respectively. A history of cold sores was obtained in 25.6% of the freshmen; none had a history of manifest genital herpes. A history of cold sores was obtained in 28% and a history of genital herpes in 1.1% of the fourth-year students. The case-weighted prevalence of HSV-1 and HSV-2 antibodies was found to be significantly elevated for a number of student characteristics. However, multiple logistic regression analyses indicated that the significant predictors of HSV-1 antibodies in this population were female gender, black race, first intercourse at age less than or equal to 15 years, total years of sexual activity, history of a partner with oral sores, and a personal history of a non-HSV sexually transmitted disease (STD). Predictors of HSV-2 antibody were black race, duration of sexual activity, and history of a non-HSV STD.

Adult↗
PubMed1990

Factors influencing the relationship between a newborn assessment of gestational maturity and the gestational age interval.

This study examines the correlation and agreement between the calculated 'gestational interval' from the date of last menstrual period (LMP) and the Ballard newborn assessment of gestational maturity. It then investigates selected maternal socio-demographic, prenatal, intrapartum and infant factors which may account for differences between these two gestational age determination methods. Single live-born deliveries (n = 10,794) were selected from a 1982-1986 medical university perinatal information data system for analysis. The Ballard assessment overestimates the LMP at earlier gestational ages and underestimates in the post-term range. The discrepancy between LMP and Ballard varies across the range of gestational age values and the extent of variation differs by several maternal and infant risk factors. These findings suggest considerable bias may result from the indiscriminate case mixing of LMP and Ballard values for use in gestational age research or in standardising developmental tests. We highlight the deficiencies in using correlation coefficients or mean differences to assess agreement between these measures.

Delivery, Obstetric↗
PubMed1990

The passage of Maryland's gun law: data and advocacy for injury prevention.

In 1988 the Maryland legislature passed an innovative law designed to limit the availability of certain types of handguns within the state. Pro-gun forces opposed the law and gathered the requisite number of petitioning signatures to refer the law to a public referendum on election day. The months preceding the referendum saw intense political campaigning over the gun law, with pro-gun forces spending $6.6 million, more money than had ever been spent in a Maryland political campaign. The handgun law was recognized to be a public health issue. This article reviews the activity involved in the passage of the law and the referendum, and discusses the role played by the Johns Hopkins injury prevention faculty in providing information to decision makers.

Adolescent↗
PubMed1989

A comparison of gestational age reporting methods based on physician estimate and date of last normal menses from fetal death reports.

Utilizing 10,587 cases from the 1980 National Center for Health Statistics Fetal Death Statistics File, we examined the comparability of two methods of determining the gestational age of a fetal death, the calculated interval from date of last normal menses (DLNM) and the physician's estimate. The physician estimated gestational age distribution exhibits even number digit preference and a distinct clustering at the 40-week value. The DLNM distribution appears more smoothly distributed but with a more pronounced post-term tail. An exact agreement between the two methods is observed in only 27.9 per cent of the cases. A 1.7 week mean difference between the methods indicates a systematic underestimation by physician reported gestational age when compared to that calculated from the DLNM, potentially biasing gestational age distributions when the physician estimate is substituted for cases with a missing DLNM. Over 8 per cent of cases 20+ weeks by DLNM are estimated as less than 20 weeks by the physician. This underestimation has important implications for the completeness of reporting of fetal deaths on vital records and the comparability of fetal death rates. Further, it may limit investigations of the completeness of reporting of less than 500 gram live births.

Female↗
PubMed1989

Variations in the reporting of gestational age at induced termination of pregnancy.

Utilizing the 1980 Induced Abortion File maintained by the National Center for Health Statistics, we compared gestational age from date of last normal menses and the physician-based estimate of gestational age. An average .51 week difference between the two methods was observed. Beyond seven weeks gestation, the date of last normal menses value was underestimated by the physician-based estimate with a markedly greater divergence after 20 weeks. A relatively greater underestimation of the date of last normal menses interval by the physician estimate was apparent for Whites after 13 weeks. The data of last normal menses value for non-state residents was overestimated across the entire range of the date of last normal menses gestational age distribution until 21 weeks.

Abortion, Induced↗
PubMed1989

[An example of research and actions related to perinatal mortality in Guadeloupe. Factors and profiles of sociodemographic risk].

Perinatal risk factors in Guadeloupe (French West Indies) have been analysed from a community-based case-control survey. Two hundred and sixty four perinatal deaths were involved along with 605 controls. Principal component factor analysis of individual risk characteristics was used to identify risk group profiles. These risk profiles were: "single women of low socio-economical status" (17% of the variability), "traditional Caribbean housewives" (14%), "single adolescents" (7%), and "immigrant women" (10%). Only the three first were significantly associated with a poor outcome for the current pregnancy. This approach may be fruitful in planning for public health interventions to prevent perinatal risk. Also, risk profile concepts may be well-accepted by physicians and care providers, in routine practice, for screening of individual at-risk patients.

Community Health Services↗
PubMed1988

Auscultated fetal heart rate accelerations. III. Use of vibratory acoustic stimulation.

The auscultated acceleration test has been proposed as a simple, inexpensive screening test for fetal health; previous studies of the auscultated acceleration test used external stimulation to elicit fetal movement. This study was conducted to explore the ability of the auscultated acceleration test to predict nonstress test results when vibratory acoustic stimulation is used to elicit fetal reactivity. After antepartum nonstress testing on 100 gravid women between 28 and 43 weeks' gestation, a 6-minute auscultated acceleration test protocol was performed with two vibratory acoustic stimulations to the maternal abdomen if no spontaneous fetal heart rate acceleration occurred. The ability of the auscultated acceleration test to predict nonstress test results after selected variables were controlled for was as follows: sensitivity, 75%; specificity, 97.6%; false-positive results, 14.3%; and false-negative results, 4.7%. Logistic regression analysis indicated that, in addition to the auscultated acceleration test, gestational age and race contributed significantly to the prediction of nonstress test results. Although specificity and the false-positive rate were improved, the use of vibratory acoustic stimulations to elicit fetal movement did not improve the validity of the auscultated acceleration test in terms of sensitivity and false-negative results over previous studies. However, the auscultated acceleration test continues to show potential as an initial screening test for fetal assessment. In addition to recommendations for further research, methodologic issues related to sampling techniques are identified.

Acoustic Stimulation↗
PubMed1987

Adolescent sexual activity and pregnancy in South Carolina: trends, risks, and practice implications.

Using South Carolina vital record data, we examined current trends in teenage pregnancy and the related pregnancy outcome risks for the period 1977 to 1984. A review of the eight-year trends in the pregnancy outcomes of teenaged mothers (less than 18 years old) indicated a significant decline (P less than .05) in the percentage of total South Carolina live infants born to teenaged mothers. While a significant increase in the teenage abortion ratio was detected, the proportion of total South Carolina pregnancies (estimated by the summation of live births, fetal deaths, and induced abortions) among teenagers significantly decreased. Compared to mothers 18 to 34 years old, teenaged mothers were nearly twice as likely to deliver prematurely, while one half as likely to receive adequate prenatal care. Their offspring were at increased risk of low birth weight and had increased fetal and infant death rates. Thirty percent of pregnancies in teenaged mothers were terminated by induced abortion, and 22% of the teenage pregnancies were to mothers aged 15 or younger, emphasizing the importance of not delaying discussions with teens of the issues of adolescent sexuality and contraception.

Abortion, Induced↗