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Biomedical subjects

F R Witter

Publications and source records attributed to F R Witter.

At least 19 recordsLinked to original sources
PubMed2004

Birth weight references for triplets.

OBJECTIVE: The purpose of this study was to formulate growth references that reflect triplet fetal and neonatal populations at each gestational age by combining serial ultrasonographic estimates of fetal weights and measured birth weights. STUDY DESIGN: This historical cohort study was based on 188 pregnancies of live-born triplets of > or =23 weeks' gestation. Ultrasonographic fetal weight measures were modeled as a function of gestational age for each infant. Linear regression models were used to fit the data, and weight percentiles were generated. RESULTS: Well-grown triplets fell substantially below singletons by 30 weeks and twins after 34 weeks. Trichorionic vs monochorionic or dichorionic placentation resulted in 27% higher growth at the 10th %ile, 5% higher growth at the 50th %ile, and 4% higher growth at the 90th %ile by 34 weeks. CONCLUSION: The overall pattern of fetal growth for well-grown triplets does not differ from that of singletons and twins until late gestation, confirming that, in utero, well-grown children have similar growth potentials, regardless of plurality.

Birth Weight↗
PubMed2000

Birth weight references for twins.

OBJECTIVE: We sought to formulate fetal and birth weight references for twins from longitudinal data. STUDY DESIGN: This historic cohort study was based on 1831 pregnancies of twins born alive at >/=28 weeks' gestation from Baltimore, Maryland; Miami, Florida; Charleston, South Carolina; and Ann Arbor, Michigan. RESULTS: When we compared singletons and twins, the percentiles of twins fell substantially below the 10th percentile of singletons by 28 weeks' gestation, below the 50th percentile by 30 weeks' gestation, and below the 90th percentile by 34 weeks' gestation. The difference at the 50th percentile was 147 g (10%) at 30 weeks' gestation, 242 g (14%) at 32 weeks' gestation, 347 g (17%) at 34 weeks' gestation, 450 g (19%) at 36 weeks' gestation, 579 g (22%) at 38 weeks' gestation, and 772 g (27%) at 40 weeks' gestation. CONCLUSION: This new reference demonstrates that, although the overall pattern of fetal growth is slower for twins versus singletons from about 30 weeks' gestation, well-grown twins and singletons do not differ as much as previously believed.

Adult↗
PubMed2000

Prostaglandin E2 preparations for preinduction cervical ripening.

PGE2 is an effective agent for cervical ripening. It is most effective when administered intravaginally. Patients with unfavorable cervices who begin labor during cervical ripening have greater gestational ages, more baseline uterine activity, more initial uterine activity in response to PGE2, and lesser cesarean delivery rate than those patients who do not begin labor during cervical ripening. However, PGE2 should not be continued or administered when the patient is in active labor because it leads to unacceptable rates of hyperstimulation. Unfortunately, cervical ripening with PGE2 has little or no effect on the overall cesarean delivery rate.

Cervical Ripening↗
PubMed1999

Duration of vaginal retention and potential duration of antiviral activity for five nonoxynol-9 containing intravaginal contraceptives.

OBJECTIVE: The purpose of this study was to determine the vaginal retention of five nonoxynol-9 intravaginal contraceptives. METHOD: An open-label crossover study in 10 premenopausal volunteers was performed at an outpatient clinical research center. The outcomes are described utilizing the median and range. RESULT: At 8 h post-instillation, the median amounts of nonoxynol-9 present in the vagina were: Delfon 7.68 mg, Conceptrol 5.18 mg, Advantage 24 1.95 mg, VCF 1.74 mg, and Semicid 1.51 mg respectively. Our calculated theoretical minimal amount needed to protect against HIV infection is 2.00 mg. CONCLUSION: The best vehicle for retaining nonoxynol-9 in the vagina appears to be foam. Further research in the effectiveness of nonoxynol-9 in prevention of the spread of HIV infection should be directed toward the use of foam vehicles to deliver nonoxynol-9 to the vagina.

Administration, Intravaginal↗
PubMed1999

Station at onset of active labor in nulliparous patients and risk of cesarean delivery.

OBJECTIVE: To determine whether term nulliparas with an unengaged vertex presentation at onset of active labor have a higher risk for cesarean delivery. METHODS: A retrospective cohort of 1250 randomly chosen nulliparous patients at 37-42 weeks' gestation who delivered between 1988 and 1989 were selected. Four hundred forty-seven patients were excluded because of nonvertex presentation, cesarean delivery before active phase of labor, multiple gestation, delivery at less than 37 weeks' or greater than 42 weeks' gestation, induction of labor, or missing charts. For the purpose of this study, active labor was defined as regular contractions with cervical dilatation of at least 3 cm. The station at onset of active labor was recorded. Engagement was considered to be at station 0 or below. RESULTS: Of the 803 patients in the study group, 567 presented unengaged and 236 patients presented engaged. The cesarean rates differed significantly between the two groups: 14% of those unengaged compared with 5% of those engaged (chi2 = 11.9, P < .001). After adjusting for confounding variables, engagement at the time of onset of active labor was associated with lower risk of cesarean delivery (odds ratio .512, 95% confidence interval .285, .922). CONCLUSION: Eighty-six percent of nulliparas with an unengaged vertex at onset of active labor delivered vaginally. Engaged vertex at the onset of active labor was associated with a lower risk of cesarean delivery.

Cesarean Section↗
PubMed1998

Population differences affect the interpretation of fetal nonstress test results.

OBJECTIVE: The object of the study was to determine whether population differences exist with respect to outcomes of women with reactive and nonreactive nonstress test results. STUDY DESIGN: An epidemiologic evaluation was conducted on 2579 women who underwent nonstress tests in the Fetal Assessment Center of the Johns Hopkins Hospital within a week of delivery. Risk factors such as hypertension, diabetes, and postterm pregnancy were used in a logistic regression model to evaluate the ability of the nonstress test to predict outcomes including proxies of fetal distress and fetal and neonatal death. The sensitivities, specificities, and predictive values of the nonstress test for predicting these outcomes in cohorts of black and white women were also determined. RESULTS: The nonstress test was consistently more sensitive for black women than for white women in predicting several perinatal outcomes, but specificity and negative predictive value were consistently lower for black women. The positive predictive value for fetal and neonatal death was higher for white women than for black women. Although the nonreactive nonstress test result seemed to be predictive of certain perinatal events, the odds ratio for predicting perinatal mortality in any study population was no greater than when the nonstress test result was reassuring. CONCLUSIONS: Epidemiologic characteristics affecting test results, such as disease prevalence and population differences, may lead to clinically significant differences in outcome prediction when these tests' results are used. These differences should be considered in the implementation of antepartum fetal testing programs.

Adult↗
PubMed1998

The importance of early weight gain in the intrauterine growth and birth weight of twins.

OBJECTIVE: It was our objective to evaluate the association between early maternal weight gain (before 20 weeks), midpregnancy weight gain (20-28 weeks), and late pregnancy weight gain (28 weeks to birth) with fetal growth and birth weight in twins. STUDY DESIGN: This historic cohort study was based on 1564 births of live twins >/=28 weeks' gestation from Baltimore, Maryland, Miami, Florida, Charleston, South Carolina, and Ann Arbor, Michigan. RESULTS: Early fetal growth was affected only by smoking and chorionicity. Factors in models of both mid and late fetal growth included maternal age, pregravid weight, parity, rates of early pregnancy and midpregnancy maternal weight gain, smoking, and pre-eclampsia. Increased midpregnancy fetal growth was associated with early maternal weight gain (10.91 g/wk per pound per week) and midpregnancy maternal weight gain (15.89 g/wk per pound per week). Increased late fetal growth was associated with early maternal weight gain (16.86 g/wk per pound per week) and midpregnancy maternal weight gain (23.88 g/wk per pound per week). Increased birth weight was associated with early (283.02 g per pound per week), mid (163.58 g per pound per week), and late (69.76 g per pound per week) maternal weight gains. CONCLUSIONS: These findings confirm the importance of early maternal weight gain in twin fetal growth and birth weight.

Adult↗
PubMed1998

Implications of the Institute of Medicine weight gain recommendations for preventing adverse pregnancy outcomes in black and white women.

OBJECTIVES: This study examined the relation between gestational weight gain and risk of delivering a small-for-gestational-age or large-for-gestational-age infant by race, along with the implications of gaining weight according to the Institute of Medicine guidelines. METHODS: Logistic regression methods were used to identify risk factors for small- and large-for-gestational-age births among 2617 Black and 1253 White women delivering at the Johns Hopkins Hospital between 1987 and 1989. RESULTS: Rate of total weight gain was related to risk of small- and large-for-gestational-age births; the relationship differed according to maternal body mass index but not race. No differences in outcome by race were evident for women with low body mass indexes; among those with average or high indexes, however, Black women were at higher risk of small-for-gestational-age births and at lower risk of large-for-gestational-age births. CONCLUSIONS: Having Black women gain at the upper end of the recommended range is unlikely to produce measurable reductions in small-for-gestational-age births. Some beneficial reductions in the risk of large-for-gestational-age births may occur if weight gain recommendations are lowered for average-weight and overweight White women.

Adolescent↗
PubMed1997

Critical periods of maternal weight gain: effect on twin birth weight.

OBJECTIVE: Our purpose was to evaluate the association between maternal weight gain and twin birth weight. STUDY DESIGN: This historic cohort study was based on 646 live-born twin births of > or = 28 weeks from Baltimore, Maryland, Miami, Florida, and Ann Arbor, Michigan. The sum of twin-pair birth weight was modeled as a function of either net maternal weight at delivery or rates of maternal weight gain with use of multiple regression. RESULTS: Birth weight was significantly associated with weight gain before 20 weeks in underweight women, before 20 weeks and after 28 weeks in overweight women, and during all three gestational periods in normal-weight women. Weight gain before 20 weeks had the largest effect on infants of underweight women, less of an effect on infants of normal-weight women, and half as much effect on infants of overweight women. Weight gain after 28 weeks significantly affected the infant birth weights of normal-weight and overweight women, but the effect was half as great among infants of the latter group. CONCLUSIONS: These findings suggest that weight gain during critical periods of gestation significantly influences twin birth weight; these critical periods vary by maternal pregravid weight status.

Adult↗
PubMed1997

Preeclampsia, labor duration and mode of delivery.

OBJECTIVE: To determine if there is a difference in the length of labor, and method of delivery between preeclamptic and normotensive patients. METHODS: A retrospective case control study was performed using a perinatal database. Study subjects included nulliparous patients diagnosed with preeclampsia, and were compared with normotensive nulliparous patients. RESULTS: There were 1454 controls and 727 subjects identified. There was no difference between groups with regard to duration of total labor. There was a statistically but not clinically significant increase in the duration of the second stage in preeclamptics (35 vs. 27 min, P = 0.003). Preeclamptics had a consistently higher risk of cesarean delivery, even when controlled for confounding variables. CONCLUSION: The clinical belief that preeclamptic patients have more rapid labors is not supported. Preeclamptics do seem to have a higher risk of cesarean delivery.

Case-Control Studies↗
PubMed1996

Determinants of gestational weight gain outside the recommended ranges among black and white women.

OBJECTIVES: To identify factors influencing risk of gaining outside the Institute of Medicine recommendations for pregnancy weight gain, and to determine whether these factors differ by race. METHODS: Multivariate methods were used to identify risk factors for under- and over-gain among 2617 black and 1253 white women delivering at the Johns Hopkins Hospital during 1987-1989. RESULTS: Only 28.2% of black women and 32.5% of white women gained the recommended amounts of weight during pregnancy. Maternal pre-pregnancy body mass index (BMI), height, parity, education, smoking, hypertension, duration of pregnancy, and fetal sex influenced risk for under-gain or over-gain. Black women were 1.51 (95% confidence interval [CI] 1.23-1.85) times more likely to under-gain, but 0.89 (95% CI 0.74-1.08) times less likely to over-gain than white women. No interactions were found between any factor examined and BMI or race. CONCLUSION: Only about one-third of women are gaining the recommended amounts of weight during pregnancy. Black women are at increased risk for gaining less weight than recommended, and selected maternal characteristics associated with race do not explain this difference. Further, risk factors for under-or over-gain do not differ between black and white women.

Adult↗
PubMed1996

Complete hydatidiform mole and surviving coexistent twin.

Twin gestations consisting of a complete hydatidiform mole and coexisting fetus are rare and associated with an increased risk of persistent gestational trophoblastic tumor. Data were abstracted from 25 well-documented cases from the literature to which we added an additional case. Cases were then separated according to whether the pregnancy was evacuated before fetal viability (19 cases) or resulted in a surviving infant (7 cases). The previable and viable groups did not differ with respect to mean age, gravidity, parity, presenting symptoms, accuracy of sonographic diagnosis in identifying the molar component, uterine size at evacuation, or the presence of preeclampsia and theca lutein cysts. Statistically significant differences (P < .05) were detected between the previable and viable groups in estimated gestational age at evacuation (18.6 weeks vs. 33.0 weeks), the discrepancy between uterine size and estimated gestational age at evacuation (8.1 weeks vs. 1.0 weeks), and preevacuation serum hCG level (1,078,416 vs. 167,883 mIU/liter). Persistent GTT developed in 68.4 percent of the previable group patients and 28.6 percent of those in the viable group (P = .09). In patients with complete hydatidiform mole and coexistent fetus, fetal survival is associated with clinical characteristics suggestive of less exuberant molar growth. The advanced gestational age required to produce a viable, surviving fetus is not an independent risk factor for the development of persistent GTT.

Female↗
PubMed1995

Urogenital infection in preeclampsia.

OBJECTIVE: The purpose of this study was to determine whether the incidence of urinary tract infections and postpartum endometritis were increased in preeclamptic pregnancies. METHOD: We conducted a retrospective study of 13852 pregnant women, using a perinatal database at The Johns Hopkins Hospital, over the past 5 years. The incidence of urinary tract infections and postpartum endometritis was analyzed using the chi-squared test and logistic regression analysis. Statistical significance was set at P < 0.05. RESULTS: There were 345 (2.5%) mild preeclamptics and 440 (3.2%) severe preeclamptics. The incidence of urinary tract infections and postpartum endometritis in preeclamptic patients was significantly higher than that in non-hypertensive pregnant patients. After controlling for confounding variables, severe preeclampsia was still found to be an independent significant risk factor for both urinary tract infections and postpartum endometritis. CONCLUSION: Our data show a significant increase in urogenital infection in preeclamptic pregnancy. This may reflect higher rates of underlying renal disease and placental bed abnormalities occurring in preeclampsia.

Adult↗