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Biomedical subjects

J M Thorp

Publications and source records attributed to J M Thorp.

At least 19 recordsLinked to original sources
PubMed2004

Risk factors for preterm birth in Vietnam.

OBJECTIVE: To identify the risk of preterm birth and possible determinants among women in Hanoi, Vietnam. METHOD: Prospective cohort study of 1709 women with singleton live births at Hanoi Obstetrics and Gynecology Hospital, Hanoi, Vietnam, June-October 2002. Logistic regression analysis was used to examine predictors of preterm birth (<37 weeks' gestation). RESULT: The risk of preterm birth was 11.8%. Physically demanding work during pregnancy, two or more prior spontaneous abortions, history of preterm birth, vaginal bleeding, inadequate prenatal care during the first 20 weeks of gestation, and history of intrauterine device use with removal less than 12 months before the current pregnancy were associated with increased risk of preterm birth (adjusted odds ratios between 1.8 and 2.6). CONCLUSION: Preterm birth is relatively frequent in this population. Beyond established risk factors, these data implicated agricultural work and physical work demands with preterm birth, as well as history of recent IUD use.

Abortion, Spontaneous↗
PubMed2003

Could ultrasonography be used by an anaesthetist to identify a specified lumbar interspace before spinal anaesthesia?

BACKGROUND: Insertion of a needle into the lumbar subarachnoid space may cause damage to the spinal cord. Current techniques to identify a safe interspace have limitations. Ultrasound was investigated as a means to improve anatomical accuracy. METHODS: Seventeen patients attending for elective magnetic resonance imaging (MRI) of the spine were studied. Ultrasonic identification of the L3-4 interspace was attempted by an anaesthetist and a marker was placed. A radiologist identified the anatomical location of the marker on the MRI scan. RESULTS: Thirteen out of 17 markers were at the L3-4 interspace; four were at the L2-3 interspace. CONCLUSIONS: These results suggest that ultrasonography may be a useful adjunct to safe subarachnoid anaesthesia.

Adult↗
PubMed2001

Frequency of eating during pregnancy and its effect on preterm delivery.

Frequency of eating or meal patterns during pregnancy may be a component of maternal nutrition relevant to pregnancy outcome. To identify meal patterns of pregnant women and investigate the relation between these meal patterns and preterm delivery, the authors performed an analysis using data from the Pregnancy, Infection, and Nutrition Study (n = 2,065). Women recruited from August 1995 to December 1998 were categorized by meal patterns on the basis of their reported number of meals (breakfast, lunch, and dinner) and snacks consumed per day during the second trimester. An optimal pattern was defined according to the Institute of Medicine recommendation of three meals and two or more snacks per day. In this population, 72 percent of the women met this recommendation, and 235 delivered preterm. Women who consumed meals/snacks less frequently were slightly heavier prior to pregnancy, were older, and had a lower total energy intake. In addition, these women had a higher risk of delivering preterm (adjusted odds ratio = 1.30, 95 percent confidence interval: 0.96, 1.76). There was no meaningful difference in the risk by early versus late preterm delivery, but those who delivered after premature rupture of the membranes (adjusted odds ratio = 1.87, 95 percent confidence interval: 1.02, 3.43) had a higher risk than those who delivered after preterm labor (adjusted odds ratio = 1.11, 95 percent confidence interval: 0.64, 1.89). This study supports previous animal model work of an association between decreased frequency of eating and preterm delivery.

Adolescent↗
PubMed2001

Sexual activity during late pregnancy and risk of preterm delivery.

OBJECTIVE: To examine the association between sexual activity during late pregnancy and preterm delivery. METHODS: Women at least 16 years old and carrying singleton fetuses were recruited between 24 and 29 weeks' gestation from prenatal clinics in central North Carolina. They were interviewed by telephone about sexual activity before and during pregnancy. One hundred eighty-seven women delivered between 29 and 36 weeks and had a follow-up interview after delivery. Four hundred nine women who were selected randomly from the cohort served as controls and had a follow-up interview between 29 and 36 weeks (mean gestational age 39.2 weeks). RESULTS: Intercourse during late pregnancy was associated with a reduced risk of preterm delivery. The conditional odds ratio (OR) was 0.34 and 95% confidence interval (CI) 0.23, 0.51 for preterm delivery within 2 weeks after intercourse. Similar decreased risk for preterm delivery was found with recent female orgasm. Adjusting for race, age, education, and living with a partner had little effect on results. Cases were more likely than controls to report poorer health, medical reasons for reducing sexual activity, less interest in sex, and receipt of advice to restrict sexual activity during pregnancy. Results did not differ substantially according to presence or absence of bacterial vaginosis at 28 weeks. CONCLUSION: These data provide evidence against the hypothesis that sexual activity generally increases risk of preterm delivery between 29 and 36 weeks. However, we cannot exclude the possibility that a small subgroup of susceptible women might have adverse consequences of sexual activity.

Adult↗
PubMed2001

Role of structural birth defects in preterm delivery.

The proportion of preterm births associated with structural birth defects has not been adequately quantified. We explored the proportion of preterm infants with structural birth defects diagnosed in the first year of life, as well as the specific phenotypes of birth defects occurring among preterm infants. The data used were from the California Birth Defects Monitoring Program, a population-based registry, as well as data from California vital records corresponding to births and fetal deaths in the period 1984-96. The prevalence of structural birth defects exceeded 8% among deliveries with gestational ages < or = 30 weeks, and prevalence decreased to 2% as gestational age increased to > or = 37 weeks gestation. The decreasing prevalence pattern with increasing gestational age was observed for a variety of anatomically defined birth defect groups suggesting that certain birth defects were not the sole contributors to the elevated prevalences among preterm births. Decreasing prevalence with increasing gestational age was also observed across strata of maternal race/ethnicities, ages, infant's sex and each year studied. These data indicate that structural birth defects may contribute significantly to the proportion of infants who are delivered before 37 weeks gestation.

Congenital Abnormalities↗
PubMed2001

Tocolytic therapy for preterm labour: assessing its potential for reducing preterm delivery.

Preterm labour (PTL) is a major contributor to preterm delivery (PTD) but delivery is often not preventable by current therapies. We conducted this study to determine the proportion of women with PTL who were and who were not candidates for tocolytic therapy. The cohort comprised residents of Olmsted County, Minnesota who delivered at >20 weeks' gestation in 1985--94 and who experienced PTL. Medical records were abstracted to identify episodes of PTL, its treatment and outcome. We developed an algorithm that accounted for gestation at delivery and pregnancy complications to determine the proportion of pregnancies complicated by PTL that were candidates for tocolytic therapy. Of 651 pregnancies complicated by PTL, a 50% probability sample, stratified by delivery year, were selected and abstracted. The cumulative incidence of PTL ranged from 3.6 to 6.4 per 100 deliveries of live or stillborn infants. Tocolysis was not contraindicated for 49.4% of all women with PTL and for a third of women with only one PTL episode. Delivery was delayed to >35 weeks in 53.8% of candidates for tocolysis. Only an additional 11.7% of women with one or more PTL episodes could have had their PTD delayed beyond 35 weeks if a perfect tocolytic therapy had been available. Many pregnancies complicated by PTL occurred at > or =35 weeks or involved maternal or obstetric factors that contraindicated tocolytic medications. The maximum incremental benefit that could be expected of a new safe and efficacious tocolytic therapy would be to reduce current PTD rates resulting from PTL by about 12%.

Adolescent↗
PubMed2001

Hormone replacement therapy in postmenopausal women: utilization of health care resources by new users.

OBJECTIVE: To determine health care resource use by new postmenopausal users of hormone replacement therapy. METHOD: We used the Saskatchewan Health administrative databases, which include a health insurance registration file, a cancer registry, and files with data on outpatient prescription drugs, hospital services, and physician services. Our population included postmenopausal women aged 55 years and over with intact uteri taking hormone replacement therapy for long-term prevention benefits, and an equal number of postmenopausal women with intact uteri with no medical contraindications to hormone replacement therapy but who did not use the therapy during the study period. RESULTS: The population in our analysis included 2632 women with new episodes of hormone replacement therapy, all with at least 3 years of follow-up. Only 42% of new hormone replacement therapy users continuously took HRT during the first year after initiation of their first new episode; a third of these were full-year users in the second year. New users of hormone replacement therapy over a 6-year follow-up period had significantly higher rates of medical care contact for diagnoses of menopausal disorders in the first year of HRT compared with subsequent years. We also found slightly elevated numbers of visits to primary care physicians and obstetrician-gynecologists and slightly increased use of endometrial biopsies and dilation and curettage procedures in the first year of hormone replacement therapy, compared with subsequent years. CONCLUSION: New users of hormone replacement therapy had higher rates of medical care for menopausal disorders in their first year of therapy compared with rates in subsequent years. After discontinuing hormone replacement therapy, utilization of medical care decreased dramatically.

Antidepressive Agents↗
PubMed2001

Altered expression of TCR-CD3zeta induced by sera from women with preeclampsia.

OBJECTIVE: To investigate TCR-CD3zeta expression by cultured T lymphocytes exposed to midtrimester sera from pregnant women in whom preeclampsia developed at term compared with normotensive pregnant control subjects. STUDY DESIGN: Sera obtained at 24 to 28 weeks' gestation from 16 nulliparous women in whom preeclampsia developed at term and from 32 gestational age-matched control subjects without preeclampsia were evaluated for TCR-CD3zeta chain expression with use of Jurkat cells. Subsets of serum samples from 6 women with preeclampsia and 6 control subjects were then evaluated for their ability to induce apoptosis and to suppress interleukin-2 production. Groups were compared by use of the Kruskal-Wallis test, and P <.05 was considered significant. RESULTS: TCR-CD3zeta chain expression in cultured T lymphocytes was suppressed in approximately 60% of untreated control subjects after incubation with sera from normotensive pregnant women compared with 30% after incubation with sera from women with preeclampsia (P <.001). T-cell apoptosis was significantly higher after incubation with sera from normotensive control subjects, as was the expression of the proapoptotic regulator Bax, compared with sera from women with preeclampsia. Interleukin-2 levels were higher in T cells incubated with sera from women in whom preeclampsia later developed compared with sera from normotensive pregnant women (27.7 ng/mL versus 72.5 ng/mL; P <.001). CONCLUSIONS: Nulliparous women in whom preeclampsia developed did not suppress TCR-CD3zeta levels to the extent of normotensive control subjects, which may be linked to decreased lymphocyte apoptosis. This occurs remotely from the manifestation of clinical disease and suggests a deficiency in a serum factor in preeclampsia that may induce T cell zeta chain suppression in normal pregnancy.

Adult↗
PubMed2001

Smoking and pregnancy outcome among African-American and white women in central North Carolina.

Despite extensive research on tobacco smoking during pregnancy, few studies address risks among African-American and white women, groups that differ in brand preference and smoking habits. The Pregnancy, Infection, and Nutrition Study is a prospective cohort study that included 2,418 women with detailed information on smoking during pregnancy, including brand, number of cigarettes per day, and changes during pregnancy. We analyzed risk of preterm birth (<37 and <34 weeks' gestation) and small-for-gestational-age deliveries in relation to tobacco use. Pregnant African-American smokers differed markedly from whites in brand preference (95% vs 26% smoked menthol cigarettes) and number of cigarettes per day (1% of African-Americans and 12% of whites smoked 20+ cigarettes per day). Smoking was not related to risk of preterm birth overall, but cotinine measured at the time of delivery was (adjusted odds ratio = 2.2, 95% confidence interval = 1.1-4.5). A clear association and dose-response gradient was present for risk of fetal growth restriction (risk ratio for 20+ cigarettes/day = 2.4, 95% confidence interval = 1.4-4.0). Associations of tobacco use with preterm premature rupture of amniotic membrane resulting in preterm birth were notably stronger than the associations with other types of preterm birth.

Black or African American↗
PubMed2000

Bacterial vaginosis and cervical dilation and effacement at 24-29 weeks' gestation.

The purpose of this study was to investigate the association between bacterial vaginosis (BV) and cervical dilation and effacement, as measures of impending preterm delivery. The Pregnancy, Infection, and Nutrition Study collected genital tract specimens and documented cervical change from 807 eligible women between 24 and 29 weeks' gestation. BV was assessed with Nugent-scored vaginal smears, and analyzed in relation to cervical measurements. At 24-29 weeks' gestation, <7% of women had a dilated cervix, 31% had a cervix < or =2 cm, and 17.3% had BV. Unadjusted analyses found no associations between BV and cervical measurements. Adjusted logistic regression suggested an association between BV and cervical effacement among women with a sexually transmitted disease (STD) earlier in pregnancy (odds ratio = 1.9, 95% CI 0.8-4.3). Stratified analyses for BV/dilation also suggested interaction with STDs. Overall, BV was not association with cervical dilation or effacement at 24-29 weeks' gestation.

Cervix Uteri↗
PubMed1999

MR imaging of levator ani muscle recovery following vaginal delivery.

Our aim was to quantify the changes that occur in the levator ani muscles (LA) after vaginal delivery using magnetic resonance imaging. Fourteen women underwent MRI 1 day postpartum. Six of them were also scanned 1, 2, 6 weeks and 6 months after delivery. LA signal intensities and thickness, in areas of the urogenital and the levator hiatus were assessed in the transverse plane. Perineal body position was measured in the sagittal plane. One day postpartum a higher T2-signal intensity of the LA compared to the obturator internus muscle was found in all women and a lower T1-signal intensity in 8 of 12 women. By 6 months these differences were present in only 1 woman in the left LA. An elevation in perineal body position of 13.4 +/- 7.3 mm (P < 0.05), as well as a decrease in the area of the urogenital hiatus by 27% (P<0.05) and of the levator hiatus by 22% (P < 0.05) by 2 weeks postpartum suggest a return of normal LA geometry. LA thickness showed interindividual variations, and a complete loss of LA tissue was found in 1 woman. Changes in LA signal intensity, topography and thickness during the puerperium can be documented using MR imaging.

Adult↗
PubMed1999

Urinary incontinence in pregnancy and the puerperium: a prospective study.

OBJECTIVE: Pregnancy and childbirth are commonly thought to be associated with the development of urinary incontinence and lower urinary tract symptoms. The purpose of this study was to assess the relationship, if any, between pregnancy and the development of lower urinary tract symptoms. STUDY DESIGN: A prospective study of lower urinary tract symptoms was carried out in a cohort of pregnant women who answered a series of symptom questionnaires and kept a 24-hour bladder chart on which frequency of urination and volumes voided were recorded throughout pregnancy and for 8 weeks after birth. RESULTS: A total of 123 women participated in the study. Mean daily urine output (P =.01) and the mean number of voids per day (P =.01) increased with gestational age and declined after delivery. Episodes of urinary incontinence peaked in the third trimester and improved after birth (P =.001). White women had higher mean voided volumes and fewer voiding episodes than did black women. Ingestion of caffeine was associated with smaller voided volumes and greater frequency of urination. CONCLUSION: Pregnancy is associated with an increase in urinary incontinence. This phenomenon decreases in the puerperium. Pregnancy and childbirth trauma are important factors in the development of urinary incontinence among women. These findings warrant further investigation.

Female↗
PubMed1999

Association between bacterial vaginosis and fetal fibronectin at 24-29 weeks' gestation.

OBJECTIVE: To investigate the relationship between fetal fibronectin and bacterial vaginosis, which are associated with an increased risk for preterm delivery. METHODS: Researchers for the Pregnancy, Infection and Nutrition Study, a cohort study of pregnant women at three central North Carolina sites, collected genital tract specimens from all enrolled women between 24 and 29 weeks' gestation. Among women with last menstrual periods between March 10, 1995, and August 15, 1996, 868 pregnancies were eligible for this analysis. Fetal fibronectin was assessed by a dipstick immunoassay kit. Bacterial vaginosis was evaluated by Nugent-scored, Gram-stained vaginal smears (scores of 7-10 considered positive). RESULTS: Overall, 6.3% of women had positive fetal fibronectin test results, and 18.8% had bacterial vaginosis. The unadjusted relative risk (RR) of fetal fibronectin-positivity comparing women with bacterial vaginosis to those without bacterial vaginosis was 1.6 (95% confidence interval [CI] 1.1, 2.5). Using multiple logistic regression to adjust for race, maternal age, parity, and location of care, women who had bacterial vaginosis and smoked at the time of recruitment were at substantially increased risk of fetal fibronectin-positivity (RR 7.8, 95% CI 2.2, 27.8) compared with smokers without bacterial vaginosis. Among nonsmokers, bacterial vaginosis was not associated with fetal fibronectin-positivity (RR 1.0, 95% CI 0.4, 2.4). These results were essentially unchanged after adding the requirement of vaginal pH exceeding 4.5 to the bacterial vaginosis definition. CONCLUSION: Fetal fibronectin was associated positively with bacterial vaginosis, but only among women who smoked. These results might provide clues as to the biologic relationship between smoking, infection, and preterm delivery.

Adolescent↗
PubMed1999

Cervical dimensions and risk of preterm birth: a prospective cohort study.

OBJECTIVE: To examine the relation between cervical dilatation and length and the risk of spontaneous preterm birth, including its subtypes preterm labor and preterm premature rupture of membranes (PROM). METHODS: Cervical dimensions assessed by clinical examination were recorded prospectively at 24-29 weeks' gestation in 871 subjects with singleton pregnancies who were followed to delivery. Relative risks (RRs) of preterm birth, preterm labor, and preterm PROM were calculated for clinically distinguishable categories of cervical dilatation and length and for cervical score (length minus dilatation). Regression analysis was used to adjust for confounding. Time to delivery from baseline examination was summarized using survival analysis. RESULTS: There were 73 spontaneous preterm births (8.3%), 46 preterm labors and 27 cases of preterm PROM. All cervical measurements were associated with increased risks of preterm birth, with increasing abnormality more strongly predictive of risk. The adjusted RR for preterm birth with dilatation of at least 0.5 cm was 2.9 (95% confidence interval [CI] 1.2, 7.3); for length of 1.5 cm or less, the RR was 2.1 (95% CI 1.0, 4.5), and for cervical score less than 2.0, the RR was 2.8 (95% CI 1.4, 5.6). The association with cervical measurements was stronger for preterm PROM than for preterm labor, although precision was limited. These measurements had high specificity (93-99%) and low sensitivity (8-20%) for predicting preterm birth. CONCLUSION: In asymptomatic women at 24-29 weeks' gestation, greater cervical dilatation and shorter length were associated with increased risk of spontaneous preterm delivery, particularly preterm PROM.

Adult↗
PubMed1999

FSH levels in relation to hysterectomy and to unilateral oophorectomy.

OBJECTIVE: To examine the association between hysterectomy, unilateral oophorectomy, and ovarian status, measured by FSH concentrations, in women aged 35-49 years. METHODS: From the National Health and Examination Survey III, 1716 women aged 35-49 years were studied. Information on menopausal status, surgical history (hysterectomy, single or bilateral oophorectomy), smoking, and other characteristics was collected in a structured interview, height and weight were measured, and one blood sample was collected. We used logistic regression to analyze FSH concentration in relation to hysterectomy and oophorectomy, controlling for age, ethnicity, body mass index, smoking, education, nulligravidity, and exercise. RESULTS: Hysterectomy with unilateral oophorectomy was associated with an increased prevalence of elevated FSH (above 20 IU/L) (adjusted odds ratio [OR] 2.4, 95% confidence interval [CI] 1.3, 4.6) compared with women who had not had hysterectomies or oophorectomies. Among women with two ovaries, hysterectomy was associated with increased prevalence of elevated FSH (adjusted OR 1.5, 95% CI 1.0, 2.5). As a comparison of the effect size, the observed association between hysterectomy and elevated FSH was smaller than the association between FSH and current smoking (OR 2.0), a factor associated with a 1-2 year decrease in mean age at natural menopause. CONCLUSION: Although the differences in FSH levels were small, there was evidence of elevated FSH in women who have had hysterectomies, even if at least one ovary remained.

Adult↗
PubMed1999

Urinary tract infections in pregnancy.

Although pregnancy does not increase the prevalence of ASB in women, it does enhance the progression rate from asymptomatic to symptomatic disease. Furthermore, ASB is associated with preterm delivery. Given the fact that identification and eradication of ASB in pregnant women can lower the likelihood of pyelonephritis and prevent preterm delivery, every gravida should be systematically screened for ASB and appropriately treated. In the authors' opinion, a first-trimester urine culture remains the screening test of choice; reliance on symptoms to prompt screening is inadequate because the state of pregnancy can provoke frequency and nocturia. Multiple antibiotic regimens for ASB are safe during pregnancy and effective.

Anti-Infective Agents, Urinary↗