Abstract:
:Late in 1995 and early 1996, 4 epidemiologic studies were published that resulted in a crude mean weighted relative risk of approximately 2 when third-generation oral contraceptives were compared with second-generation oral contraceptives as risk factors for venous thromboembolism. This article reviews empirical evidence on bias or systematic error that may have influenced the estimates of association. The Bradford-Hill criteria to distinguish causality from an observed association were used to consider whether third-generation oral contraceptives cause an apparent excess in the occurrence of venous thromboembolism. Bias is more likely than a causal relationship to explain the associations observed for venous thromboembolism. For myocardial infarction, bias may mask the full benefit of third-generation oral contraceptives. For stroke, the question of causality is moot because statistically significant differences between third- and second-generation products have not been detected. The clinical importance and the public health significance of any differences among the various products with respect to adverse cardiovascular outcomes are trivial and undetectable because of the extremely low incidence of those disorders among users of oral contraceptives. The oral contraceptive pill is 99.9% effective when used correctly. All oral contraceptives on the market are safe and getting safer. :Four epidemiologic studies published in 1995-96 reported a crude mean weighted relative risk for venous thromboembolism of approximately 2 when third-generation oral contraceptives (OCs) were compared with second-generation formulations. This paper considers empirical evidence of bias or systematic error that may have influenced the estimates of association. Specifically, it asks 1) whether an odds ratio of 2 for venous thromboembolism in users of third- compared with second-generation OCs is accurate or has been spuriously increased by bias and 2) whether causality can be assumed from the observed association reflected in a relative risk of 2. Bias--particularly healthy user, prescription, and referral bias--is more likely than a causal association to explain the associations observed for venous thromboembolism. For myocardial infarction, bias may mask the full benefit of third-generation OCs. For stroke, the question of causality is moot because statistically significant differences between third- and second-generation OCs have not been detected. Moreover, the clinical importance and public health significance of any differences between these OCs in terms of adverse cardiovascular outcomes are trivial because of the extremely low incidence of these disorders among OC users.
journal_name
Am J Obstet Gynecoljournal_title
American journal of obstetrics and gynecologyauthors
Spitzer WOdoi
10.1053/ob.1998.v179.a93059subject
Has Abstractpub_date
1998-09-01 00:00:00pages
S43-50issue
3 Pt 2eissn
0002-9378issn
1097-6868pii
S00002937898005080journal_volume
179pub_type
杂志文章,评审abstract::Placental-related fetal growth restriction arises primarily due to deficient remodeling of the uterine spiral arteries supplying the placenta during early pregnancy. The resultant malperfusion induces cell stress within the placental tissues, leading to selective suppression of protein synthesis and reduced cell proli...
journal_title:American journal of obstetrics and gynecology
pub_type: 杂志文章,评审
doi:10.1016/j.ajog.2017.11.577
更新日期:2018-02-01 00:00:00
abstract::We provide a justification for preventive ethics in obstetric practice. Four clinical guides to resolving ethical conflicts between pregnant women and their physicians can be identified: (1) informed consent as an ongoing dialogue between the pregnant woman and her physician, (2) negotiation as a clinical strategy, (3...
journal_title:American journal of obstetrics and gynecology
pub_type: 杂志文章
doi:10.1016/0002-9378(90)90374-g
更新日期:1990-02-01 00:00:00
abstract:BACKGROUND:Fibroid tumors are the most common benign tumors in women of reproductive age. Treatment is usually indicated for those who are symptomatic, with different techniques being used. OBJECTIVE:The purpose of this study was to compare the long-term outcome of laparoscopic myomectomy with magnetic resonance-guide...
journal_title:American journal of obstetrics and gynecology
pub_type: 杂志文章
doi:10.1016/j.ajog.2018.09.002
更新日期:2018-10-01 00:00:00
abstract::Chronic pelvic pain is common among women of reproductive age and is associated with significant morbidity and comorbidities. In this Viewpoint, we explore the evolutionary cause of pelvic pain and summarize evidence that supports a menstruation-related evolutionary cause of chronic visceral pelvic pain: (1) lifetime ...
journal_title:American journal of obstetrics and gynecology
pub_type: 杂志文章
doi:10.1016/j.ajog.2016.05.019
更新日期:2016-08-01 00:00:00
abstract:OBJECTIVE:The purpose of this study was to determine whether ultrasonography is more accurate than vaginal examination in the determination of fetal occiput position in the second stage of labor. STUDY DESIGN:Eighty-eight patients in the second stage of labor were evaluated by vaginal examination and by combined trans...
journal_title:American journal of obstetrics and gynecology
pub_type: 杂志文章
doi:10.1016/j.ajog.2004.01.029
更新日期:2004-08-01 00:00:00
abstract:OBJECTIVE:We conducted a meta-analysis using individual patient data to examine the efficacy of exercise for improving bone mineral density at the femoral neck in postmenopausal women. STUDY DESIGN:Ten controlled clinical trials that included 595 subjects (aged 42-92 years) met our criteria for inclusion. Changes in f...
journal_title:American journal of obstetrics and gynecology
pub_type: 杂志文章,meta分析
doi:10.1016/j.ajog.2005.09.006
更新日期:2006-03-01 00:00:00
abstract:OBJECTIVE:The purpose of this study was to evaluate the accuracy of clinical measurement of cervical dilation with a position-tracking system during vaginal examination. STUDY DESIGN:This prospective study that was conducted in Poissy, France, Brooklyn, NY, and Haifa, Israel, included 333 measurements that were perfor...
journal_title:American journal of obstetrics and gynecology
pub_type: 杂志文章
doi:10.1016/j.ajog.2009.01.002
更新日期:2009-04-01 00:00:00
abstract::Behavioral states in the near-term human fetus have been described during pregnancy. The aim of this study was to observe whether these same states are present during labor. Nine patients with uncomplicated singleton pregnancies participated. Fetal heart rate and uterine contractions were recorded. Fetal eye, mouth, r...
journal_title:American journal of obstetrics and gynecology
pub_type: 杂志文章
doi:10.1016/s0002-9378(85)80071-5
更新日期:1985-08-01 00:00:00
abstract::Because serum CA-125 concentrations are increased in women with endometriosis, our objective was to determine whether CA-125 levels could be used to differentiate endometriotic from nonendometriotic benign cysts. During a 2-year period, all women who had an endometrioma (n = 33) or a nonendometriotic cyst (n = 27) tha...
journal_title:American journal of obstetrics and gynecology
pub_type: 杂志文章
doi:10.1016/s0002-9378(87)80237-5
更新日期:1987-12-01 00:00:00
abstract:BACKGROUND:Preeclampsia (PE) affects 2-3% of all pregnancies and is a major cause of maternal and perinatal morbidity and mortality. The traditional approach to screening for PE is to use a risk-scoring system based on maternal demographic characteristics and medical history (maternal factors), but the performance of s...
journal_title:American journal of obstetrics and gynecology
pub_type: 杂志文章
doi:10.1016/j.ajog.2015.11.016
更新日期:2016-05-01 00:00:00
abstract:OBJECTIVE:The aim of this study was to determine whether any association exists between preeclampsia and circulating platelet activating factor levels. STUDY DESIGN:We performed a cross-sectional observational study of circulating platelet activating factor concentrations in nonpregnant women, normotensive pregnant wo...
journal_title:American journal of obstetrics and gynecology
pub_type: 杂志文章
doi:10.1067/mob.2000.108894
更新日期:2000-10-01 00:00:00
abstract:OBJECTIVE:Our purpose was to determine the maximal fetal exposure to radiation by use of thermoluminescent dosimeters when pelvic measurements were performed by standard or modified digital radiography. STUDY DESIGN:Digital radiography of the pelvis was performed according to a standard technique. Lithium fluoride the...
journal_title:American journal of obstetrics and gynecology
pub_type: 杂志文章
doi:10.1016/s0002-9378(96)70133-3
更新日期:1996-08-01 00:00:00
abstract:OBJECTIVE:The route of delivery in eclampsia is controversial. We hypothesized that adverse maternal and perinatal outcomes may not be improved by early cesarean delivery. STUDY DESIGN:This was a randomized controlled exploratory trial carried out in a rural teaching institution. In all, 200 eclampsia cases, carrying ...
journal_title:American journal of obstetrics and gynecology
pub_type: 杂志文章,随机对照试验
doi:10.1016/j.ajog.2012.04.009
更新日期:2012-06-01 00:00:00
abstract:OBJECTIVE:We evaluated the effects of coliform endotoxin on the circulating levels of atrial natriuretic factor and renal function. To understand the direct effects of endotoxin in the release of atrial natriuretic factor by cardiac tissue, studies in isolated rat atria were performed. STUDY DESIGN:In vivo studies wer...
journal_title:American journal of obstetrics and gynecology
pub_type: 杂志文章
doi:10.1016/s0002-9378(98)70246-7
更新日期:1998-07-01 00:00:00
abstract::In Finland an organized mass screening program covers the total female population. Based on the material (429,832) from a nationwide mass screening registry it was estimated that the female population not subjected to electrocoagulation of the uterine cervix (362,511) had a sixfold risk of frankly invasive carcinoma, ...
journal_title:American journal of obstetrics and gynecology
pub_type: 杂志文章
doi:10.1016/0002-9378(78)90115-1
更新日期:1978-07-01 00:00:00
abstract::Nifedipine is a calcium channel blocker that reduces blood pressure and increases renal blood flow. This double-blind investigation evaluated the effect of nifedipine in postpartum patients with severe preeclampsia. Thirty-one patients were randomized to receive either nifedipine (10 mg) or placebo every 4 hours begin...
journal_title:American journal of obstetrics and gynecology
pub_type: 临床试验,杂志文章,随机对照试验
doi:10.1016/0002-9378(90)91011-z
更新日期:1990-03-01 00:00:00
abstract:OBJECTIVES:Our purpose was to determine whether blockade of inducible or endothelial nitric oxide synthesis prevents maternal vasodilation and blunting of angiotensin II responsiveness in the pregnant rat. STUDY DESIGN:Pregnant and nonpregnant rats were given (1) drinking water alone (untreated), (2) drinking water co...
journal_title:American journal of obstetrics and gynecology
pub_type: 杂志文章
doi:10.1016/s0002-9378(97)70404-6
更新日期:1997-05-01 00:00:00
abstract::Obstetric uterine rupture has previously been reported after the laparoscopic removal of deep intramural myomas, but never has it been reported to follow the removal of superficial myomas. A 39-year-old primigravid woman with a history of a superficial subserous laparoscopic myomectomy was seen for acute abdominal sym...
journal_title:American journal of obstetrics and gynecology
pub_type: 杂志文章
doi:10.1016/s0002-9378(97)70110-8
更新日期:1997-12-01 00:00:00
abstract::Estrogen receptors and progesterone receptors were measured in tumors from patients with previously untreated endometrial carcinoma before and after a 5-day course of tamoxifen citrate. On initial biopsy, 13 of 25 tumors (52%) were progesterone receptor-positive, whereas 21 of 25 tumors (84%) were progesterone recepto...
journal_title:American journal of obstetrics and gynecology
pub_type: 杂志文章
doi:10.1016/0002-9378(84)90187-x
更新日期:1984-05-15 00:00:00
abstract::X-ray evaluation of the pelvis plays a pivotal role in selecting term breech presentation for a possible trial of labor. Even minimal degrees of disproportion may have disastrous consequences for the aftercoming head. Our evaluation of x-ray pelvimetry by computerized tomography scanning suggests it is probably more a...
journal_title:American journal of obstetrics and gynecology
pub_type: 杂志文章
doi:10.1016/0002-9378(85)90695-7
更新日期:1985-12-15 00:00:00
abstract::A 35-year-old woman underwent exploratory laparotomy for ovarian enlargement, massive ascites, and intestinal obstruction. Sclerosing peritonitis associated with florid mesothelial hyperplasia, ovarian fibromatosis, and endometriosis were diagnosed postoperatively. We add to the literature this new association of bila...
journal_title:American journal of obstetrics and gynecology
pub_type: 杂志文章
doi:10.1016/s0002-9378(97)70581-7
更新日期:1997-03-01 00:00:00
abstract::Chromosomal microarray analysis is a high-resolution, whole-genome technique used to identify chromosomal abnormalities, including those detected by conventional cytogenetic techniques, as well as small submicroscopic deletions and duplications referred to as copy number variants. Because chromosomal microarray analys...
journal_title:American journal of obstetrics and gynecology
pub_type: 杂志文章
doi:10.1016/j.ajog.2016.07.016
更新日期:2016-10-01 00:00:00
abstract:BACKGROUND:Significant racial/ethnic disparities in unintended pregnancy persist in the United States, with the highest rates observed among low-income black and Hispanic women. Differences in contraceptive preferences, beliefs, and self-efficacy may be instrumental in understanding contraceptive behaviors that underli...
journal_title:American journal of obstetrics and gynecology
pub_type: 杂志文章
doi:10.1016/j.ajog.2016.12.178
更新日期:2017-05-01 00:00:00
abstract::Different perspectives toward symptoms of urogenital aging exist among postmenopausal women, influenced by social and cultural factors, but one constant is that women rarely feel able to discuss urogenital problems freely--with their physicians, husbands, or friends. European women >55 years old were brought up to pri...
journal_title:American journal of obstetrics and gynecology
pub_type: 杂志文章,评审
doi:10.1016/s0002-9378(98)70556-3
更新日期:1998-05-01 00:00:00
abstract::The placenta is a highly metabolically active organ fulfilling the bioenergetic and biosynthetic needs to support its own rapid growth and that of the fetus. Placental metabolic dysfunction is a common occurrence in preeclampsia although its causal relationship to the pathophysiology is unclear. At the outset, this ma...
journal_title:American journal of obstetrics and gynecology
pub_type: 杂志文章,评审
doi:10.1016/j.ajog.2020.11.005
更新日期:2020-11-13 00:00:00
abstract::To assess uterine activity before labor in patients delivering preterm, at term, and postterm, the maximum spontaneous contraction frequency per 10-minute window during the initial portion of antepartum fetal heart rate monitoring was analyzed. Patients with multiple gestation, third trimester bleeding, polyhydramnios...
journal_title:American journal of obstetrics and gynecology
pub_type: 杂志文章
doi:10.1016/0002-9378(88)90353-5
更新日期:1988-06-01 00:00:00
abstract:OBJECTIVE:We sought to determine whether the success of intrauterine insemination (IUI) varies based on the type of health care provider performing the procedure. STUDY DESIGN:This was a retrospective cohort study set at an infertility clinic at an academic institution. The patients who comprised this study were 1575 ...
journal_title:American journal of obstetrics and gynecology
pub_type: 杂志文章
doi:10.1016/j.ajog.2014.05.033
更新日期:2014-11-01 00:00:00
abstract::Clostridium sordellii is a common soil and enteric bacterium that is infrequently recovered from the vagina. We describe three women in which C. sordellii caused puerperal infection and a distinctive and lethal toxic shock-like syndrome. Patients were less than 1 week post partum and each had a single, limited focus o...
journal_title:American journal of obstetrics and gynecology
pub_type: 杂志文章
doi:10.1016/0002-9378(89)90768-0
更新日期:1989-10-01 00:00:00
abstract::Universal access to contraception benefits society: unintended pregnancies, maternal mortality, preterm birth, abortions, and obesity would be reduced by increasing access to affordable contraception. Women should be able to choose when and whether to use contraception, choose which method to use, and have ready acces...
journal_title:American journal of obstetrics and gynecology
pub_type: 杂志文章
doi:10.1016/j.ajog.2019.09.014
更新日期:2020-02-01 00:00:00
abstract:OBJECTIVE:We sought to identify modifiable risk factors for excessive gestational weight gain (GWG). STUDY DESIGN:We assessed associations of diet and physical activity with excessive GWG among 1388 women from the Project Viva cohort study. RESULTS:Three hundred seventy-nine women (27%) were overweight (body mass ind...
journal_title:American journal of obstetrics and gynecology
pub_type: 杂志文章,多中心研究
doi:10.1016/j.ajog.2009.02.025
更新日期:2009-07-01 00:00:00