As with other fields, medical sciences are subject to different sources of bias. While understanding sources of bias is a key element for drawing valid conclusions, bias in health research continues to be a very sensitive issue that can affect the focus and outcome of investigations. Information bias, otherwise known as misclassification, is one of the most common sources of bias that affects the validity of health research. It originates from the approach that is utilized to obtain or confirm study measurements. This paper seeks to raise awareness of information bias in observational and experimental research study designs as well as to enrich discussions concerning bias problems. Specifying the types of bias can be essential to limit its effects and, the use of adjustment methods might serve to improve clinical evaluation and health care practice.

/pdf/information-bias-in-health-research-definition-pitfalls-and-1as13hgk9p.pdf

Information bias in health research: definition, pitfalls, and adjustment methods.

Before marketing a new drug, the manufacturer almost never tests the product in pregnant women to determine its effects on the fetus. Consequently, most drugs are not labeled for use during pregnancy. Typically, descriptions of drugs that appear in the Physicians' Desk Reference and similar sources contain statements such as, “Use in pregnancy is not recommended unless the potential benefits justify the potential risks to the fetus.” Since the risk has been adequately established for only a few drugs, physicians caring for pregnant women have very little information to help them decide whether the potential benefits to the mother outweigh . . .

Drugs in Pregnancy

Background Many women of reproductive age have depression, necessitating therapy with either a tricyclic antidepressant drug or a drug, such as fluoxetine, that inhibits the reuptake of serotonin. Whether these drugs affect fetal neurodevelopment is not known. Methods We studied the children of 80 mothers who had received a tricyclic antidepressant drug during pregnancy, 55 children whose mothers had received fluoxetine during pregnancy, and 84 children whose mothers had not been exposed during pregnancy to any agent known to affect the fetus adversely. The children's global IQ and language development were assessed between 16 and 86 months of postnatal age by age-appropriate Bayley Scales of Infant Development or the McCarthy Scales of Children's Abilities (for IQ) and the Reynell Developmental Language Scales. Results The mean (±SD) global IQ scores were 118±17 in the children of mothers who received a tricyclic antidepressant drug, 117±17 in those whose mothers received fluoxetine, and 115±14 in those ...

Neurodevelopment of Children Exposed in Utero to Antidepressant Drugs

Dose–response relationship between alcohol consumption before and during pregnancy and the risks of low birthweight, preterm birth and small for gestational age (SGA)—a systematic review and meta‐analyses

OBJECTIVE: Previous work suggested that first-trimester exposure to tricyclic antidepressants or fluoxetine does not affect adversely child IQ and language development. However, many women need antidepressants throughout pregnancy to avoid morbidity and suicide attempts. Little is known about the fetal safety of tricyclic antidepressants and fluoxetine when taken throughout pregnancy. The goal of this study was to assess the effects of tricyclic antidepressants and fluoxetine used throughout gestation on child IQ, language, and behavior. METHOD: In a prospective study, mother-child pairs exposed throughout gestation to tricyclic antidepressants (N=46) or fluoxetine (N=40) and an unexposed, not depressed comparison group (N=36) were blindly assessed. The three groups were compared in terms of the children’s IQ, language, behavior, and temperament between ages 15 and 71 months. The authors adjusted for independent variables such as duration and severity of maternal depression, duration of pharmacological tr...

/pdf/child-development-following-exposure-to-tricyclic-34jewi0zz8.pdf

Child Development Following Exposure to Tricyclic Antidepressants or Fluoxetine Throughout Fetal Life: A Prospective, Controlled Study

Perception of teratogenic risk by pregnant women exposed to drugs and chemicals during the first trimester.

Case-control studies on effects of durgs in pregnancy rely heavily on maternal recall. At the Motherisk Program in Toronto we counsel women during early pregnancy on the risk of drug and chemical exposure; subsequently, we follow up the outcome of pregnancy after birth. This cohort has given us an opportunity to assess the magnitude of recall of early pregnancy exposure and determinants likely to affect it in 145 consecutive cases. The mean recall of exposure identity was 62%, while accurate recall of timing of exposure was 37% and of dosage 24%. Exposures that prompted the clinic visit, chronic therapeutic exposures, environmental agents, and known teratogens were recalled significantly better than were other exposures. Accurate report of smoking was significantly higher than of alcohol use (79.4% vs. 59%, respectively, P = .0002). The number of agents consumed by the pregnant woman negatively correlated with her recall; mean recall of 1 agent was 85% vs. only 40% recall of 4 agents. Women ≥ 30 years of age recalled significantly worse (mean ± SEM, 52 ± 4%) than women younger than 30 (70 ± 4%), P = .002) despite a similar mean number of exposures. No difference in mean recall was found between women having normal (n = 112) or adverse pregnancy outcome (n = 33). There was a recall bias in reporting alcohol consumption; postnatally, women with adverse outcome tended to report significantly less than the amount initially reported by them.

Yaacov Feldman

Papers

Perception of teratogenic risk by pregnant women exposed to drugs and chemicals during the first trimester.

Determinants of recall and recall bias in studying drug and chemical exposure in pregnancy.

Perception of teratogenic risk by pregnant women exposed to drugs and chemicals during the first trimester