Abstract:
:Information bias occurs when any information used in a study is either measured or recorded inaccurately. This paper describes some of the most common types of information bias, using examples from obstetrics and gynecology, and describes how information bias may affect results of observational studies. Non-differential misclassification occurs when the degree of misclassification of exposure status among those with and those without the disease is the same; in cohort studies, this type of bias is most likely and will bias estimates toward no association when exposure is dichotomized. Non-differential underreporting of an exposure with more than two categories may mask a true threshold effect as a dose-response relation and, if a true threshold effect exists, the threshold will be set at too low a level, if the exposure is underreported. Differential misclassification may cause bias in either direction and is particularly likely, when exposure status is reported after the outcome occurred. Misclassification of confounders is an issue that needs special attention by researchers, as failure to measure accurately one or more (strong) confounders may seriously bias the observed results. Misclassification of disease status may also cause bias of estimates of association in either direction. Information bias is probably best prevented during planning of data collection, as there are few and insufficient methods available for correcting inaccurate information.
journal_name
Acta Obstet Gynecol Scandjournal_title
Acta obstetricia et gynecologica Scandinavicaauthors
Kesmodel USdoi
10.1111/aogs.13330subject
Has Abstractpub_date
2018-04-01 00:00:00pages
417-423issue
4eissn
0001-6349issn
1600-0412journal_volume
97pub_type
杂志文章,评审abstract::We determined the effect of cord blood collection before placental expulsion on postpartum maternal blood loss in a retrospective study between a group of cord blood donors and a group of non-donors. The study was conducted in a university hospital blood bank and obstetric services and included Spanish women entered i...
journal_title:Acta obstetricia et gynecologica Scandinavica
pub_type: 杂志文章
doi:10.1111/j.1600-0412.2011.01182.x
更新日期:2011-09-01 00:00:00
abstract:OBJECTIVE:To provide insight into the differential effect of immigration on cesarean section (CS) rates, using the Robson classification. DESIGN:A population-based study using birth certificates from the birth registry of 2009. SETTING:All births in two of the three Belgian regions excluding Flanders. POPULATION:37 ...
journal_title:Acta obstetricia et gynecologica Scandinavica
pub_type: 杂志文章
doi:10.1111/aogs.12003
更新日期:2013-02-01 00:00:00
abstract:BACKGROUND:To improve the diagnostic accuracy of concurrent renal disease in hypertension of pregnancy, biopsy evaluation is essential. In addition, establishing underlying renal disease is important for prognosis on future pregnancies. We therefore designed a study to determine the diagnostic yield of postpartum renal...
journal_title:Acta obstetricia et gynecologica Scandinavica
pub_type: 杂志文章
doi:
更新日期:2000-05-01 00:00:00
abstract:BACKGROUND:A study was initiated to identify background factors, clinical features and pre-operative scoring systems of importance for future selection of patients suitable for fertility surgery. METHODS:Surgical procedures, background factors and scoring systems for tubal lesions and adnexal adhesions and risk factor...
journal_title:Acta obstetricia et gynecologica Scandinavica
pub_type: 杂志文章
doi:10.3109/00016349509024450
更新日期:1995-04-01 00:00:00
abstract::A clinical trial was conducted at 47 centers in 11 countries to assess the efficacy and acceptability of a monophasic oral contraceptive containing 30 micrograms ethinyl estradiol and 150 micrograms desogestrel. 1,613 women took part for a total of 23,258 cycles. One pregnancy occurred in a cycle where two consecutive...
journal_title:Acta obstetricia et gynecologica Scandinavica
pub_type: 临床试验,杂志文章
doi:10.3109/00016348809004193
更新日期:1988-01-01 00:00:00
abstract:OBJECTIVES:We estimated the associations of parity and offspring birthweight with the risk of shoulder dystocia, and studied whether the association of offspring birthweight differed by parity. DESIGN:Population-based register study. SETTING:The Medical Birth Registry of Norway was used to identify all deliveries bet...
journal_title:Acta obstetricia et gynecologica Scandinavica
pub_type: 杂志文章
doi:10.1111/j.1600-0412.2011.01354.x
更新日期:2012-04-01 00:00:00
abstract:BACKGROUND:Interventions that may help shorten the duration of pregnancy in an African setting where facilities for fetal monitoring in post-term pregnancy are limited, and induction is not without its hazards, are needed. AIM:To determine whether outpatient administration of intravaginal misoprostol safely decreases ...
journal_title:Acta obstetricia et gynecologica Scandinavica
pub_type: 临床试验,杂志文章,随机对照试验
doi:10.1111/j.0001-6349.2005.00655.x
更新日期:2005-07-01 00:00:00
abstract:BACKGROUND:To evaluate the effects of L-arginine (ARG) infusion, the nitric oxide as substrate, on the utero-placental circulation at third trimester. METHODS:Three groups of nine pregnant women each were infused i.v. with 30 g ARG, for 30 minutes. One group served as control, and the two remnants were composed by pat...
journal_title:Acta obstetricia et gynecologica Scandinavica
pub_type: 临床试验,杂志文章
doi:10.3109/00016349609047088
更新日期:1996-03-01 00:00:00
abstract::The purpose of this case-control study was to compare implantation, pregnancy, and live birth rate of cryopreserved embryos with that of fresh embryos. A total of 1,488 assisted reproductive technology (ART) trials including 188 cryopreserved embryo replacement trials were reviewed. After proofing the exclusion criter...
journal_title:Acta obstetricia et gynecologica Scandinavica
pub_type: 杂志文章
doi:10.1080/00016340903093575
更新日期:2009-01-01 00:00:00
abstract::The effect of physical exercise on beta-endorphin (beta-E) concentration in plasma was studied in 8 non-pregnant and in 8 pregnant women in their last trimester of pregnancy, using a 10-min bicycle ergometer test. In the non-pregnant women the mean beta-E levels were 2.4 +/- 0.7 (S.E.) pmol/l before the test, 4.3 +/- ...
journal_title:Acta obstetricia et gynecologica Scandinavica
pub_type: 杂志文章
doi:10.3109/00016348609158397
更新日期:1986-01-01 00:00:00
abstract::Perinatal morbidity and mortality are still high in cases of intra-uterine growth retardation. Present screening methods select large risk groups and have a low positive predictive value. Instruments which could be used as indicators for those cases within the risk group needing close fetal monitoring would be valuabl...
journal_title:Acta obstetricia et gynecologica Scandinavica
pub_type: 杂志文章
doi:10.3109/00016349209009916
更新日期:1992-04-01 00:00:00
abstract::Collagen from the chorioamnion units from premature and term pregnancies was solubilized by limited pepsin digestion and subjected to SDS-PAG electrophoresis. Collagen types were quantitated by densitometry. It was found that collagen type III decreases and collagen type V tends to increase as gestational age advances...
journal_title:Acta obstetricia et gynecologica Scandinavica
pub_type: 杂志文章
doi:
更新日期:1988-01-01 00:00:00
abstract:INTRODUCTION:Approximately 85% of vaginal deliveries are accompanied by perineal trauma. The objective of this trial was to compare the incidence of perineal trauma after primary delivery of either the anterior or posterior shoulder during vaginal delivery. MATERIAL AND METHODS:This was a randomized single-blinded tri...
journal_title:Acta obstetricia et gynecologica Scandinavica
pub_type: 杂志文章,随机对照试验
doi:10.1111/aogs.12914
更新日期:2016-09-01 00:00:00
abstract:BACKGROUND:Description of incidence, clinical signs, symptoms, and consequences of eclampsia in Scandinavia, and assessment of substandard care and potential preventability. METHODS:A descriptive cohort study including all women giving birth in a 2-year period (mid-1998-mid-2000) in Scandinavia. Notifications of eclam...
journal_title:Acta obstetricia et gynecologica Scandinavica
pub_type: 杂志文章
doi:10.1080/00016340600607149
更新日期:2006-01-01 00:00:00
abstract:BACKGROUND:In the present study we report on the results of a retrospective study on the effect on survival of the pelvic lymphadenectomy in a group of 294 patients with stage Ia2-IIa cervical carcinoma treated by radical hysterectomy from 1984 through 1996 at the Leiden University Medical Center. METHODS:Lymphadenect...
journal_title:Acta obstetricia et gynecologica Scandinavica
pub_type: 杂志文章
doi:
更新日期:2000-01-01 00:00:00
abstract:OBJECTIVE:To assess the role of the placental arterial Doppler examination at 23-24 gestational weeks for predicting adverse perinatal outcome in high-risk pregnancies. DESIGN:Retrospective register study. SETTING:Skåne University Hospital in Malmö. POPULATION:Six hundred and forty-five women with high-risk pregnanc...
journal_title:Acta obstetricia et gynecologica Scandinavica
pub_type: 杂志文章
doi:10.1111/aogs.12488
更新日期:2014-12-01 00:00:00
abstract::Consanguinity is common in Arab countries. The Sultanate of Oman has a relatively small population with a high prevalence of consanguineous marriages. This is a retrospective study of women who had three or more consecutive miscarriages between January 2002 and December 2008, investigated in the non-pregnant state. Ag...
journal_title:Acta obstetricia et gynecologica Scandinavica
pub_type: 杂志文章
doi:10.1111/j.1600-0412.2011.01200.x
更新日期:2011-10-01 00:00:00
abstract:OBJECTIVE:Recent studies have shown that high interleukin-6 (IL-6) secretion may aggravate insulin resistance in pregnancy and participate in the pathogenesis of gestational diabetes mellitus (GDM). The aim of this study was to determine whether the presence of GDM is associated with elevated IL-6 concentrations and wh...
journal_title:Acta obstetricia et gynecologica Scandinavica
pub_type: 杂志文章
doi:10.1111/j.1600-0412.2011.01094.x
更新日期:2011-05-01 00:00:00
abstract:BACKGROUND:Anal sphincter tears during vaginal delivery are a major cause of anal incontinence. We wanted to assess the incidence in a Norwegian county where primary repairs are performed in four hospitals using similar per- and postoperative protocol for the treatment of such injuries. METHODS:A postal questionnaire ...
journal_title:Acta obstetricia et gynecologica Scandinavica
pub_type: 杂志文章
doi:10.1111/j.0001-6349.2004.00647.x
更新日期:2004-10-01 00:00:00
abstract:BACKGROUND:The cause of transient stress urinary incontinence during pregnancy remains uncertain. Anatomical change, such as a pressure effect of the enlarged uterus, changes in renal function, and alterations in bladder and urethral function have been proposed. There is little information about the role of reproductiv...
journal_title:Acta obstetricia et gynecologica Scandinavica
pub_type: 杂志文章
doi:10.1034/j.1600-0412.2001.801209.x
更新日期:2001-12-01 00:00:00
abstract:OBJECTIVE:To evaluate our experience with prophylactic balloon occlusion of the internal iliac arteries as a part of a multidisciplinary algorithm for the management of placenta percreta. DESIGN:Consecutive case series. Setting. Rigshospitalet, Copenhagen University Hospital, Denmark. Sample. Seventeen women with plac...
journal_title:Acta obstetricia et gynecologica Scandinavica
pub_type: 杂志文章
doi:10.1111/j.1600-0412.2012.01451.x
更新日期:2013-04-01 00:00:00
abstract:BACKGROUND:To determine the influence of hyaluronan and its receptor CD44 in the angiogenesis and invasiveness of intravenous leiomyomatosis (IVL). METHODS:Paraffin-embedded sections from four IVL cases and 10 uterine leiomyoma cases were immunohistochemically stained for CD34, CD44, basic fibroblast growth factor (bF...
journal_title:Acta obstetricia et gynecologica Scandinavica
pub_type: 杂志文章
doi:10.1111/j.0001-6349.2005.00707.x
更新日期:2005-04-01 00:00:00
abstract:OBJECTIVE:To quantify inter- and intra-observer agreement of non-reassuring intrapartum cardiotocography (CTG) patterns and subsequent clinical management. DESIGN:Methodological study. SETTING:University Medical Center. POPULATION:CTG patterns of 79 women beyond 37 weeks of gestation with a singleton fetus in vertex...
journal_title:Acta obstetricia et gynecologica Scandinavica
pub_type: 杂志文章
doi:10.1111/aogs.12371
更新日期:2014-06-01 00:00:00
abstract:INTRODUCTION:Because little is known about the effects of maternal position on periodic changes in the maternal heart rate (MHR) in late pregnancy, a prospective observational study was done at Tygerberg Academic Hospital in Cape Town. Pregnant women admitted for elective cesarean section were studied to determine the ...
journal_title:Acta obstetricia et gynecologica Scandinavica
pub_type: 杂志文章
doi:10.1111/aogs.12763
更新日期:2015-12-01 00:00:00
abstract:BACKGROUND:As a vaporizing electrode has been successfully used to treat submucous myomas, we evaluated its safety and efficacy in performing endometrial ablation. METHODS:Forty consecutive women with established menorrhagia with (n=26) and without (n=14) submucous myomas were enrolled in a prospective, noncomparative...
journal_title:Acta obstetricia et gynecologica Scandinavica
pub_type: 临床试验,杂志文章
doi:10.1034/j.1600-0412.1998.770619.x
更新日期:1998-07-01 00:00:00
abstract:BACKGROUND:To compare neonatal and maternal outcomes for breech first twins according to whether vaginal or cesarean delivery was planned and to verify that in appropriate selected cases, attempted vaginal delivery is a reasonable choice. METHODS:A retrospective study of all twin pregnancies with the first twin in bre...
journal_title:Acta obstetricia et gynecologica Scandinavica
pub_type: 杂志文章,多中心研究
doi:10.1080/00016340601089594
更新日期:2007-01-01 00:00:00
abstract:OBJECTIVE:To describe the establishment and organization of the Danish Fetal Medicine Database and to report national results of first-trimester combined screening for trisomy 21 in the 5-year period 2008-2012. DESIGN:National register study using prospectively collected first-trimester screening data from the Danish ...
journal_title:Acta obstetricia et gynecologica Scandinavica
pub_type: 杂志文章
doi:10.1111/aogs.12581
更新日期:2015-06-01 00:00:00
abstract::Plasma antithrombin III (AT III) was studied longitudinally in 15 subjects (13 patients and 2 volunteers), who used the "morning-after pill" (5 mg ethinylestradiol daily for 5 days). The mean decrease in AT III level in the 13 patients was 17% of the pre-treatment value. From additional observations made in 2 of the p...
journal_title:Acta obstetricia et gynecologica Scandinavica
pub_type: 杂志文章
doi:10.3109/00016348309156240
更新日期:1983-01-01 00:00:00
abstract:BACKGROUND:Cytogenetic studies in patients with reproductive failure AIM:To investigate the contribution of chromosomal abnormalities in sub fertility and in couples with repeated abortions. METHODS:Hundred and 13 couples who had at least two or more spontaneous abortions and 65 women and 63 men with infertility were...
journal_title:Acta obstetricia et gynecologica Scandinavica
pub_type: 杂志文章
doi:10.1034/j.1600-0412.2003.820109.x
更新日期:2003-01-01 00:00:00
abstract:OBJECTIVE:To determine the performance of trained midwives in second trimester ultrasound screening for fetal structural abnormalities in a low-risk population. DESIGN:Retrospective study. SETTING:University Department of Obstetrics and Gynecology. POPULATION:About 13,882 women with singleton pregnancies. METHODS:T...
journal_title:Acta obstetricia et gynecologica Scandinavica
pub_type: 杂志文章
doi:10.1080/00016340902934688
更新日期:2009-01-01 00:00:00