Effects of physical activity on preterm birth.

The authors conducted a cohort study of low income women to determine the effect of physical activity on the risk of preterm birth. Women were sampled prenatally from four clinic sites and were scheduled for delivery at the University of Maryland Medical Systems (UMMS). Women who delivered infants at UMMS but who had received no prenatal care were also eligible. Preterm delivery was defined as a delivery prior to 37 completed weeks gestation. After adjusting for confounders, the odds of preterm delivery were increased for women who climbed stairs > or = 10 times per day (odds ratio (OR) = 1.60, 95% confidence interval 1.05-2.46) and for women who engaged in purposive walking > or = 4 days per week (OR = 2.10, 95% CI 1.38-3.20). Leisure-time exercise (> or = 60 days in the first and second trimesters combined) had a protective effect on preterm delivery (OR = 0.51, 95% CI 0.27-0.95). Television viewing had a U-shaped relation with preterm delivery (ORs (95% CI): < 15 hours, 2.09 (1.21-3.61); 29-42 hours, 1.50 (0.84-2.67); > 42 hours, 3.05 (1.75-5.40)). While the results support current recommendations regarding leisure-time activities, activities of daily living appear to increase risk of preterm delivery among low income women. These findings and those for television watching warrant further investigation.

Pregnancy and the risk of stroke.

BACKGROUND: It is widely believed that pregnancy increases the risk of stroke, but there are few data available to quantify that risk. METHODS: We identified all female patients 15 through 44 years of age in central Maryland and Washington, D.C., who were discharged from any of 46 hospitals in the study area in 1988 or 1991. Two neurologists reviewed each case, using data from the women's medical records. We determined whether the women had been pregnant at the time of the stroke or up to six weeks before it occurred. For purposes of this analysis, the six-week period after pregnancy could begin with an induced or spontaneous abortion or with the delivery of a live or stillborn child. RESULTS: Seventeen cerebral infarctions and 14 intracerebral hemorrhages occurred in women who were or had recently been pregnant (pregnancy-related strokes), and there were 175 cerebral infarctions and 48 intracerebral hemorrhages that were not related to pregnancy. For cerebral infarction, the relative risk during pregnancy, adjusted age and race, was 0.7 (95 percent confidence interval, 0.3 to 1.6), but it increased to 8.7 for the postpartum period (after a live birth or stillbirth) (95 percent confidence interval, 4.6 to 16.7). For intracerebral hemorrhage, the adjusted relative risk was 2.5 during pregnancy (95 percent confidence interval, 1.0 to 6.4) but 28.3 for the postpartum period (95 percent confidence interval, 13.0 to 61.4). Overall, for either type of stroke during or within six weeks after pregnancy, the adjusted relative risk was 2.4 (95 percent confidence interval, 1.6 to 3.6), and the attributable, or excess, risk was 8.1 strokes per 100,000 pregnancies (95 percent confidence interval, 6.4 to 9.7). CONCLUSIONS: The risks of both cerebral infarction and intracerebral hemorrhage are increased in the six weeks after delivery but not during pregnancy itself.

Is manual palpation of uterine contractions accurate?

OBJECTIVE: The aims of this study were to assess the accuracy of uterine contraction palpation, determine whether the accuracy of palpation improves with experience, determine clinical factors that affect the accuracy of palpation, and evaluate the range of intrauterine pressure present when an observer notes the contraction to be mild, moderate, or strong. STUDY DESIGN: A total of 236 observations were obtained by use of intrauterine pressure catheters on 46 laboring patients in the first stage of labor. The blinded observers (obstetrics and gynecology residents, maternal-fetal medicine fellows and faculty, and labor and delivery nurses) were asked to label a contraction as mild, moderate, or strong. Patient's height, weight, parity, and gestational age, use of oxytocin, use of epidural anesthesia, and laboring position, and the level of training of the observer were noted. RESULTS: Mild, moderate, and strong contractions had intrauterine pressures of 35.2 +/- 33.8 mm Hg (+/- 2 SD), 44.9 +/- 35.4 mm Hg, and 55.5 +/- 28.0 mm Hg, respectively. The observers were accurate in predicting contraction strength 49% of the time. There was no improvement in accuracy with increased physician experience. All physicians as a group were more accurate than nurses (p < 0.05). Accuracy was not affected by clinical variables. CONCLUSION: Manual palpation of uterine contractions is an inaccurate means of determining contraction strength.

Simulating birth to investigate clinician-applied loads on newborns.

This report describes the design, development and testing of a force-measuring birth stimulator. Designed to mimic the feel of an obstetric emergency, the simulator is named shoulder dystocia birth model (SDBM). The SDBM consists of a simply supported overhung beam, instrumented with two strain gauges and one commercially-available sensor, all of which are embedded in a maternal manikin that rests on a height-adjustable scissors jack. Rigidly affixed to the free end of the beam, a model of a newborn head protrudes from the manikin to allow physicians to simulate the loads they exert when delivering a newborn. A microcomputer-based data acquisition system monitors, analyses and processes the output from the gauges and the sensor in real time. The system measures axial force and vertical force to within 2% accuracy and the end-moment to within 5% accuracy. Testing with 15 University of Maryland clinicians simulating routine, difficult and SD deliveries reveals average peak force magnitudes of 68 N, 118 N and 172 N and average peak moment magnitudes of 138 N. cm, 384 N.cm and 621 N.cm, respectively. The standard deviations for these average peak values are large indicating wide variation in perceived loads required to deliver. Confirming clinical observation, average peak forces for some difficult and many shoulder dystocia deliveries exceed the force necessary to induce clavicle fracture at birth.

Comparing clinician-applied loads for routine, difficult, and shoulder dystocia deliveries.

OBJECTIVE: Our goal was to examine and compare clinician-applied loads during simulated vaginal delivery. STUDY DESIGN: We developed a birthing model and a microcomputer data acquisition system and used them to measure clinician-applied extraction forces, moment, and rates for three perceived categories of delivery. In 39 experiments, clinicians simulated delivery of the fetal shoulders during vaginal delivery for routine, difficult, and shoulder dystocia deliveries. RESULTS: Clinicians averaged 84 N combined force and 473 N-cm neck-bending moment for routine deliveries, 122 N and 697 N-cm for difficult deliveries, and 163 N and 700 N-cm for shoulder dystocia deliveries (p < 0.002). No force or moment parameter was associated with clinician gender or experience. Force levels exceeding 100 N are reached for many clinicians (74% and 82%) for difficult and shoulder dystocia deliveries and for some clinicians (31%) for routine deliveries (p < 0.0001). CONCLUSION: We conclude that simulating shoulder dystocia in the laboratory may be useful in measuring extraction forces and neck-bending moment and that birthing models can be used to train clinicians in force, moment, and rate perception.

Comparing mothers' reports on the content of prenatal care received with recommended national guidelines for care.

The Public Health Service's Expert Panel on the Content of Prenatal Care Report in 1989 provided detailed guidelines for the components of each prenatal visit. However, the extent to which women were receiving the recommended care when the guidelines were being formulated has yet to be determined. The 1988 National Maternal and Infant Health Survey results permit an examination of the proportion of women who reported receiving some of the recommended procedures. Women were asked if they received six of the recommended procedures (blood pressure measurement, urine test, blood test, weight and height taken, pelvic examination, and pregnancy history) in the first two visits, and whether they received seven types of advice or counseling (nutrition; vitamin use; smoking, alcohol, and drug use cessation; breastfeeding; and maternal weight gain) any time during their pregnancy. Only 56 percent of the respondents said they received all of the recommended procedures in the first two visits, and only 32 percent of the respondents said they received advice in all of the areas. Logistic regression analysis indicated that women receiving their care from private offices were significantly less likely to receive all the procedures and advice than women at publicly funded sites of care. This study suggests that recommendations of the Public Health Service's expert panel were not being met.

Relation of the content of prenatal care to the risk of low birth weight. Maternal reports of health behavior advice and initial prenatal care procedures.

OBJECTIVE: Numerous studies have found a relationship between the quantity of prenatal care received and birth outcomes. Few studies have had the opportunity to examine the content of prenatal care. This study examined the relationship between two components of the content of prenatal care: maternal reports of health behavior advice received and initial prenatal care procedures performed during the first two visits and low birth weight in a national sample of women. Advice and initial procedures were categorized based on the recommendations of the US Public Health Service Expert Panel on the Content of Prenatal Care. DESIGN: Interview survey of a nationally representative sample of women who had live births in 1988. PARTICIPANTS: A total of 9394 women, with data from the National Maternal and Infant Health Survey. MAIN OUTCOME MEASURE: Low birth weight (< 2500 g) as reported on the birth certificate. RESULTS: After controlling for other sociodemographic, utilization, medical, and behavioral factors, women who reported not receiving all the types of advice recommended by the Expert Panel on the Content of Prenatal Care were more likely to have a low-birth-weight infant compared with women who reported receiving the optimal level of advice (odds ratio = 1.38; 95% confidence interval, 1.18 to 1.60). There were no differences between women who reported receiving all the recommended initial prenatal care procedures and those who reported not receiving all recommended prenatal care (odds ratio = 1.00; 95% confidence interval, 0.87 to 1.14). CONCLUSION: These data suggest that women who report receiving sufficient health behavior advice as part of their prenatal care are at lower risk of delivering a low-birth-weight infant.

Measurement of blood volume with an enriched stable isotope of chromium (53Cr) and isotope dilution by combined gas chromatography-mass spectrometry.

We used an established isotope dilution gas chromatography-mass spectrometry method to measure blood volumes with an enriched stable isotope of chromium. The results were compared with those of the conventional method, which involves radioactive 51Cr. The two methods were compared simultaneously in two male subjects of different sizes, and essentially identical volumes were obtained. The isotope dilution method is insensitive to contamination with natural (unenriched) chromium and can be used to measure all of the stable isotopes of chromium. The method has potential applications in simultaneous erythrocyte survival studies. The absence of radioactivity makes possible an accurate means of studying blood volume changes in children and during pregnancy.

Randomized comparison of home uterine activity monitoring and routine care in patients discharged after treatment for preterm labor.

OBJECTIVE: To determine whether home uterine activity monitoring reduces the likelihood of preterm birth in women successfully treated for preterm labor in their current pregnancies. METHODS: Women between 20-34 weeks' gestation who had been treated successfully for preterm labor were solicited to participate in a randomized clinical trial of home uterine activity monitoring versus routine high-risk care. The sample size of 56 was based on power calculations using the results of earlier investigators. Twenty-eight women were randomized to home uterine activity monitoring and 29 were assigned to the type of care appropriate for women discharged after hospitalization for parenteral treatment of preterm labor. One of the routine-care subjects was lost to follow-up. The two groups were comparable in distribution for race, insurance status, multiple gestation, marital status, gestational age at beginning of the study, and incidence of prior preterm birth. RESULTS: The 28 women receiving routine care had a 54% incidence of preterm birth, whereas the incidence was 57% in monitored women (relative risk 1.08, 95% confidence interval 0.6-1.9; P = .79). The incidences of delivery before 32 weeks and 34 weeks also were unaffected by the intervention. CONCLUSION: Home uterine activity monitoring is not effective in reducing the likelihood of preterm delivery in patients successfully treated for preterm labor in their current pregnancies.

Double-blind randomized study comparing amoxicillin and erythromycin for the treatment of Chlamydia trachomatis in pregnancy.

OBJECTIVE: To compare the efficacy and patient tolerance of amoxicillin to that of erythromycin in the treatment of lower genital tract chlamydia infections during pregnancy. METHODS: A double-blind, randomized study was conducted comparing oral amoxicillin 500 mg three times daily versus oral erythromycin 500 mg four times daily for 7 days. One hundred forty-three women with positive cervical cultures for chlamydia at less than 36 weeks' gestation were enrolled. A test-of-cure culture was obtained 4 weeks after entry into the study and side effects were assessed. Success of the regimen was defined as completing the course of medication and having a negative test-of-cure culture. RESULTS: Thirty of the 65 women in the erythromycin group (46.1%) developed symptoms while taking the medication and 15 of them were unable to continue treatment (23.1%). In contrast, five of the 65 women (7.7%) in the amoxicillin group became symptomatic, with only one of these patients intolerant of the side effects (1.5%) (P < .001). Of the 50 patients in the erythromycin group who were able to complete their course of medication, only three had a positive test of cure (6.0%). In comparison, nine of the 64 patients (14.1%) taking amoxicillin who completed their course had positive cultures at test of cure. This difference was not statistically significant (P = .14). Forty-seven of the 65 patients (72.3%) in the erythromycin group successfully completed their regimen, compared to 55 of the 65 women (84.6%) in the amoxicillin group. This difference was not statistically significant. CONCLUSIONS: These findings suggest that amoxicillin is a reasonable alternative for the treatment of chlamydia in pregnant patients intolerant to erythromycin. The incidence of side effects and intolerance to therapy for amoxicillin are less than those for erythromycin.

The general medical record. Concepts and suggestions for implementation.

Our view of a general medical record consists of a combination of distinct departmental- and specialty-specific medical records and an organizing kernel that contains arguably critical information. Because this system allows each clinical entity to evolve its own system, clinical priorities do not have to be negotiated or compromised. Additionally, subsystem or departmental medical records can be easily revised without disturbing the general medical record because of the modular design. Although the system seems robust with respect to design considerations, only implementation can provide adequate tests.

Validity of self-reported pregravid weight.

Self-reported pregravid weight is a commonly used baseline indicator of nutritional status in prenatal weight gain studies. This study assesses the validity of self-reported pregravid weight in 1591 gravidas who entered into prenatal care within the first trimester of pregnancy from 1986 to 1988 at the University of Maryland Medical Systems. A significant difference of 4.3 lb (t = 25.56, P < 0.001) was found between self-reported pregravid weight and estimated pregravid weight. Limits of agreement (interval within which 95% of the differences between the self-reported and measured weights) were constructed by population characteristics. Multiple linear regression models with estimated pregravid weight as the dependent variable were estimated by self-reported pregravid weight, body weight, height, age, race, education, insurance status, and marital status groups. A model with self-reported pregravid weight as the sole independent variable was found to explain 88% of the variance in estimated pregravid weight. Results of this study suggest that the validity of self-report pregravid weight varies with sociodemographic and anthropometric factors. Adjustment by a simple regression equation can minimize error in self-reported pregravid weight.

Plasma and erythrocyte magnesium changes following a glucose challenge during pregnancy.

This study examined the effects of pregnancy and glucose loading on plasma and erythrocyte (RBC) magnesium (Mg) concentrations. In a completely randomized design with repeated measures, 15 nonpregnant, 15 early pregnant (13-17 weeks) and 15 late pregnant (28-34 weeks) women ingested 100 g glucose. Blood was collected at 0, 30, 60, 120 and 180 minutes to evaluate changes in Mg levels. Fasting plasma Mg concentrations decreased slightly but not significantly as gestational age of the groups increased. Fasting RBC Mg concentrations were significantly higher (p less than 0.05) in late pregnant women compared with early pregnant and nonpregnant women. Plasma Mg responses to a glucose challenge in nonpregnant women exhibited a curvilinear pattern whereas responses in pregnant women appeared unaffected by the glucose challenge. RBC Mg concentrations for nonpregnant and early pregnant women failed to respond to the glucose challenge whereas it decreased in a linear pattern during late pregnancy. The diabetogenic effect of late pregnancy appears to affect RBC Mg. This redistribution of Mg during late pregnancy could suggest a possible role for RBC as a Mg pool.

Creating a unit-specific charging system.

A totally nurse-dependent charging system developed specifically for the labor and delivery suite at the University of Maryland Medical System is described in the article. This easy and effective method of charging was incorporated into an already existing patient census and classification system. The number of relative value units has increased by more than 30%, and the amount of revenue billed has increased by more than $800,000 in the first 10 months after implementation.