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Biomedical subjects

J D Shelton

Publications and source records attributed to J D Shelton.

At least 19 recordsLinked to original sources
PubMed2001

Risk of clinical pelvic inflammatory disease attributable to an intrauterine device.

Use of the intrauterine device (IUD) is avoided because of perceived risk of pelvic inflammatory disease (PID) associated with sexually transmitted Infections (STI). Calculation of the risk of clinical pelvic inflammatory disease showed that the estimated risk was low (0.15%), even with a high STI prevalence. This estimated risk argues for making IUDs more available.

Africa↗
PubMed2000

Empirically based conversion factors for calculating couple-years of protection.

Couple-years of protection (CYP) is one of several commonly used indicators to assess international family planning efforts. It has been the subject of much debate, relating in part to the specific conversion factors used to translate the quantity of the respective contraceptive methods distributed to a single measure of protection. This article outlines a comprehensive effort to revisit those conversion factors based on the best available empirical evidence. In most instances, the analysis supports previously established standard conversion factors. However, there are two notable departures. Fewer condoms and spermicides are recommended for each CYP (120 vs. 150), primarily because coital frequency among condom users is lower than previously assumed. Furthermore, for sterilization, the authors recommend the use of country or region-specific conversion factors. Every program evaluation indicator has strengths and weaknesses, and the best program evaluation efforts use a variety of indicators. If CYP is used to evaluate programs, however, the authors believe that the conversion factors presented reflect the best available evidence.

Adolescent↗
PubMed1983

Risk of breast, uterine corpus, and ovarian cancer in women receiving medroxyprogesterone injections.

Animal studies have yielded conflicting results on the carcinogenicity of long-acting progestins. Since more than 1.5 million women worldwide are currently receiving injections of a contraceptive progestin, depot medroxyprogesterone acetate, this is potentially an important public health problem. We obtained information on the occurrence of breast, uterine, and ovarian cancer among 5,000 black women attending a metropolitan hospital's family planning clinic who had received injections of medroxyprogesterone for contraception (between 1967 and 1976). The women were followed up for four to 13 years after their initial medroxyprogesterone injection. We compared the observed number of cancer cases in these women with the expected number based on annual age-, race-, and sex-specific rates derived from National Cancer Institute data. During more than 40,000 woman-years of observation, we found no evidence of an increased risk of developing cancer of the breast, uterine corpus, or ovary in these women. After adjusting for possible underascertainment of cancer because of incomplete follow-up, we found the relative risk for medroxyprogesterone users to be 0.7 for breast cancer (95% confidence limits, 0.3 to 1.4), 1.2 (95% confidence limits, 0.1 to 6.7) for cancer of the uterine corpus, and 0.8 (95% confidence limits, 0.1 to 4.6) for ovarian cancer.

Adolescent↗
PubMed1982

Prostacyclin from the uterus and woman's cardiovascular advantage.

Prostacyclin emanating from the uterus is proposed as a major contributor to the reduced risk of coronary disease among women. The hypothesis is supported by (1) epidemiologic evidence that the risk of myocardial infarction increases markedly following hysterectomy whether or not the ovaries are removed, (2) evidence that premenopausal women may have higher circulating levels of prostacyclin than men of comparable ages, (3) production of prostacyclin by uterine tissue homogenates, (4) preliminary data showing high levels of prostacyclin's stable end-product metabolite in the venous drainage of the uterus, and (5) plausible mechanisms through which prostacyclin could produce a salutary effect on coronary disease. If an appreciable portion of woman's coronary advantage over man relates to differences in uterine production and circulating levels of this natural hormone or similar hormones such as 6-keto-PGE1, then the implications for therapy, prevention, and understanding of the underlying disease processes are considerable. In any case, physicians in practice should recognize the potential of the uterus as a systemically active organ whose removal significantly increases subsequent risk of myocardial infarction.

6-Ketoprostaglandin F1 alpha↗
PubMed1981

The Pearl Pregnancy Index reexamined: still useful for clinical trials of contraceptives.

Data from 25 studies of intrauterine contraceptive devices show close agreement between the Pearl Pregnancy Index and a cumulative, 12 month, life-table pregnancy rate. Analysis of data from the early stages of these clinical trials shows the Pearl Index to be superior to the short-term life table in predicting the outcome of the study. The error introduced by using the Pearl Index as a single measure of contraceptive efficacy in clinical trials, under conditions in which those trials are often carried out, is probably very minor compared to the effect of situational factors that affect studies and to differences among various life-table methodologies. The real strength of the life-table analysis of contraceptive performance is not the single, summary, 12 month pregnancy rate it provides, but the complete picture of various reasons for termination over time, particularly when a large number of woman-months of experience has accrued.

Actuarial Analysis↗
PubMed1981

Postpartum contraception.

Recently-delivered women who wish to avoid pregnancy should initiate contraception before ovulation. Since the return of ovulation is not predictable, regardless of the woman's lactation status and duration of postpartum amenorrhea, contraception should be initiated as soon as is reasonable after delivery. The choice of contraceptive method will depend on several factors, including: the woman's lactation status, the preference of the woman and her partner, and the health status of the newborns. For women who do not wish to have additional children, tubal sterilization through a minilaparotomy incision is the procedure of choice. For other women who are not lactating, all methods, with the exception of the use of cervical caps and diaphragms, may be initiated immediately after delivery. However, preference should be given to IUD use by lactating and non-lactating woman, especially for women who may not return for any additional postpartum care.

Contraception↗
PubMed1980

Necrotizing enterocolitis: a prospective multicenter investigation.

Several pre- and post-natal factors possibly important in determining which infants will develop necrotizing enterocolitis (NEC) and which of these infants will die with this disease were prospectively studied in 1976 in 11 infants with radiographic or pathologic evidence of the disease from 12 institutions in the United States and 111 weight-matched, institution-matched control infants. By multivariant discriminant analysis, the authors idenfitied 10 independent significant determinants of NEC and 10 determinants predictive of a fatal outcome among case infants. Determinants of NEC were: Apgar score deterioration; presence of a patent ductus arteriosus; maternal receipt of anesthesia during delivery; infant not treated with parenteral gentamicin before the onset of disease; infant receipt of 10% dextrose solution; treatment of mother with antibiotics during pregnancy; hyperalimentation or gavage feedings; premature rupture of membranes. Important morbid events among cases included red blood cell transfusions, gas in the portal system, premature rupture of membranes, abdominal distension, isolation of Klebsiella organisms from the blood, surgery, prolonged perinatal oxygen requirement, and lower Apgar 2 score. Attempts to modify preventable risk factors may decrease the incidence (2.4 cases per 1000 live births) and case fatality (41%) documented in this study.

Anesthesia, Obstetrical↗