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Biomedical subjects

F F Johnson

Publications and source records attributed to F F Johnson.

12 recordsLinked to original sources
PubMed1995

Cervical competence as a continuum: a study of ultrasonographic cervical length and obstetric performance.

OBJECTIVE: Our purpose was to investigate the hypothesis that cervical competence is a continuum that is related to cervical length and is reflected by pregnancy history. STUDY DESIGN: A cross-sectional study was performed of cervical length measured by transvaginal ultrasonography in women with prior preterm delivery at < or = 26 weeks, 27 to 32 weeks, and 33 to 35 weeks compared with women with cervical incompetence and normal controls delivered at term. RESULTS: Transvaginal cervical length was measured during pregnancy in 32 subjects with cervical incompetence, 98 with previous preterm birth < or = 26 weeks, 98 with previous preterm birth at 27 to 32 weeks, 127 with previous preterm birth at 33 to 35 weeks, and 106 normal controls. The relationship between obstetric history and cervical length was evaluated by analysis of variance. The gestational age at the first preterm delivery was significantly correlated with cervical length in the current pregnancy at each gestational interval between 20 and 30 weeks in a continuous manner. CONCLUSION: Cervical competence is a continuous rather than categoric variable and is indicated indirectly by measurement of the length of the cervix.

Adult↗
PubMed1994

Cervical sonography in preterm labor.

OBJECTIVE: To improve the accuracy of the diagnosis of preterm labor by comparing transvaginal sonography to digital examination of the cervix. METHODS: We performed transvaginal sonography in women with preterm labor who had completed a course of parenteral tocolysis. Cervical length was measured according to criteria reported previously. Cervical sonographic findings were not used in diagnosis or management. Sonographic cervical length was compared to digital assessment of dilation and effacement to assess the risk of preterm birth after treatment for preterm labor. RESULTS: Forty-eight singleton and 12 twin gestations were studied. Thirty women were nulliparous and 30 were parous. The mean (+/- standard deviation) gestational age was 31.1 +/- 2.7 weeks (range 24-35) at the examination and 35.6 +/- 2.9 weeks (range 26-43) at delivery. Twenty-four subjects delivered before 36 weeks' gestation and 36 delivered at or after 36 weeks. Cervical sonography was distinctly superior to digital assessment of dilation and effacement as a test for delivery before 36 weeks, when compared using receiver operating characteristic curves. This analysis indicated a cervical length of 30 mm as the best cutoff to maximize sensitivity and specificity. All 24 subjects who delivered preterm had cervical lengths less than 30 mm. Cervical sonography was especially useful in selecting women with preterm labor who would not deliver prematurely, ie, a high negative predictive value. None of 15 women whose cervical length was 30 mm or more delivered spontaneously before 36 weeks. CONCLUSION. Among women treated for preterm labor, a cervical length of at least 30 mm predicted a low likelihood of preterm birth. Cervical sonography may improve the accuracy of diagnosis in women treated for preterm labor.

Adult↗
PubMed1994

A prospective evaluation of the signs and symptoms of preterm labor.

OBJECTIVE: To describe the time relation between symptoms, contractions, and the clinical diagnosis of preterm labor. METHODS: We analyzed the records from 57 women who were enrolled in a previously reported trial of home uterine monitoring and who developed preterm labor while using the monitor. In a post hoc descriptive study of signs and symptoms during the 7 days preceding a diagnosis of preterm labor, we reviewed uterine contraction records and study records of the responses to a standard list of questions about potential symptoms of preterm labor. RESULTS: Monitored contraction frequency increased on the day of preterm labor diagnosis, from an average of fewer than three per hour to five per hour, but was not increased on any of the days before the day of diagnosis. Neither symptoms nor contraction monitoring strips indicated any significant changes more than 24 hours before the clinical diagnosis was made. Self-palpated and monitored contractions were the most common symptoms of preterm labor. CONCLUSION: A clinical diagnosis of preterm labor is preceded by an increase in self-palpated and monitored contractions and other symptoms for less than 24 hours.

Adult↗
PubMed1990

Symptoms that precede preterm labor and preterm premature rupture of the membranes.

Great emphasis has been placed on recognition of the early warning symptoms of preterm labor by both pregnant women and health care providers. In addition to the expected increase in both painless and painful uterine contractions, several symptoms have been commonly cited in textbooks and patient educational materials as preceding preterm labor including menstrual-like cramps, backache, pelvic pressure, and an increased amount of vaginal discharge. We interviewed 107 women with preterm labor, 102 women with preterm prematurely ruptured membranes, and 106 ambulatory normal pregnant women to ascertain the frequency of each of eight putative warning symptoms of preterm labor in each group. Preterm labor patients were distinguished as expected from both normal women and amniorrhexis patients by a greater frequency of painful and painless contractions. Menstrual cramps, backache, and increased vaginal discharge, symptoms often said to be normally present in pregnancy, were also significantly more common in preterm labor patients than in women with preterm membrane rupture and in normal subjects.

Adolescent↗
PubMed1990

Ambulatory uterine activity monitoring in the post-hospital care of patients with preterm labor.

Care of women with preterm labor has been reported by Katz et al to be enhanced by use of an electronic uterine contraction monitor. We enrolled 76 women with singleton gestations who had been successfully treated for preterm labor into a prospective randomized trial, assigning subjects in a ratio of 1:2 to a group of 27 receiving education and self-palpation (EP) or to a group of 49 receiving education and an ambulatory monitor (EM). Subjects in both groups received an intensive education session at entry and were contacted frequently (5 days/week in EP and daily in EM) thereafter to report symptoms and frequency of contractions. Physicians were advised to adjust the dosage of oral tocolytic to maintain fewer than four contractions per hour. Rates of recurrent preterm labor and preterm delivery did not differ between the groups. Although the sample size in this study is too small to exclude entirely the possibility of alpha error, our inability to demonstrate a difference suggests that the improvement reported by others in pregnancy outcome associated with use of an electronic ambulatory contraction monitor may be the result of daily attention to symptoms and signs of preterm labor.

Ambulatory Care↗
PubMed1990

Uterine activity and symptoms as predictors of preterm labor.

Women enrolled in a previously reported prospective trial of ambulatory tocodynamometry who developed preterm labor while using an ambulatory tocodynamometer were candidates for this analysis. Data from 51 women who met these entry criteria were evaluated and placed into four groups according to the initial reason for evaluation for preterm labor: monitored uterine activity, symptoms, both contractions and symptoms, or cervical examination at a routine office visit. Less than half (43%) had both subjective symptoms and an increase in monitored contraction frequency; 24% were initially identified by symptoms, 24% by uterine activity, and 10% at a routine office visit. We conclude that waiting for both an increase in uterine activity and subjective symptoms of labor will delay diagnosis in 50% or more of preterm labor patients and that women at risk of preterm birth should be evaluated promptly if either contractions or symptoms persist.

Adult↗
PubMed1988

A prospective random trial of home uterine activity monitoring in pregnancies at increased risk of preterm labor. Part II.

Daily uterine activity monitoring has been reported to be helpful in improving the percentage of women with preterm labor eligible for tocolysis, with a corresponding decline in preterm delivery. The first year of our trial of ambulatory tocodynamometry in 157 women at risk of preterm labor did not reveal significant differences in rates of preterm labor and preterm delivery between two groups of women randomly assigned to receive preterm labor education, frequent (5 days/week) telephone contact, and self-palpation of uterine activity (group EP), or to preterm labor education, daily telephone contact, and the Term Guard ambulatory uterine activity monitor (group EM). We report results from the second year (n = 152), yielding a total study population of 309. Forty-three subjects were later excluded, producing 266 subjects who completed the study. Comparison of preterm labor and preterm delivery rates, mean birth weight, and gestational age at delivery revealed no significant differences between the groups for the second year or for the combined data from both years of the study. Interestingly, comparison of all subjects enrolled in year 1 with all those enrolled in year 2 reveals significant decreases in the rates of both preterm labor and preterm delivery. Frequent attention to symptoms and signs of preterm labor, and improved patient and physician education and awareness, may be responsible for this decline in preterm labor and delivery in high-risk pregnancies.

Female↗
PubMed1988

Prevention of preterm birth.

Prevention of prematurity is the principal goal of all obstetric care. Although conquest of preterm births may yet be a distant goal that will require substantial improvements in understanding the pathophysiology of PTD, interim progress is possible. Increased attention to prematurity prevention as the focus of prenatal care can have an impact now, without introducing unproven or hazardous techniques or medication. Reproductive health care aimed at the prevention and elimination of social, demographic, and medical correlates of prematurity can yield results if obstetricians take the lead in educating both patients and society at large about the hazards of prematurity. Progress is more likely if a global strategy is used in all pregnancies as reported by Papiernik et al., Meis et al., and Herron et al. These studies have similar messages of hope and caution: All reported benefit in decreasing the frequency of preterm births, all required substantial and widespread patient and provider education, and all required a sustained effort before any effect was noted. Main et al. showed that these programs are not likely to produce a quick turnaround in PTD rates in all populations; progress will be slow. Reports of limited success or even failure should not result in abandonment of the goal, but rather in renewed and imaginative efforts toward it.

Bed Rest↗
PubMed1987

A prospective random trial of home uterine activity monitoring in pregnancies at increased risk of preterm labor.

In a prospective trial we enrolled 157 women at increased risk of preterm birth, randomly assigning women in a ratio of 1:2 to receive either frequent (greater than or equal to 5 days/wk) nursing contact, education in preterm labor symptoms, and self-palpation of uterine activity (group E, n = 50), or daily nursing contact, preterm labor education, and the Term Guard home uterine activity monitor (group EM, n = 107). Comparison of the rate of preterm birth, the incidence of preterm labor and successful tocolysis, and the mean birth weight and gestational age revealed no significant differences and suggested that beneficial effects previously attributed to monitored contraction data may in fact be the result of frequent (five or more times per week) nursing contact and careful attention to preterm labor symptoms and perceived contractions.

Clinical Trials as Topic↗