Recall bias in a case-control surveillance system on the use of medicine during pregnancy

Longevity and mortality of owned dogs in England

Improved understanding of longevity represents a significant welfare opportunity for the domestic dog, given its unparalleled morphological diversity. Epidemiological research using electronic patient records (EPRs) collected from primary veterinary practices overcomes many inherent limitations of referral clinic, owner questionnaire and pet insurance data. Clinical health data from 102,609 owned dogs attending first opinion veterinary practices (n=86) in central and southeast England were analysed, focusing on 5095 confirmed deaths. Of deceased dogs with information available, 3961 (77.9%) were purebred, 2386 (47.0%) were female, 2528 (49.8%) were neutered and 1105 (21.7%) were insured. The overall median longevity was 12.0 years (IQR 8.9-14.2). The longest-lived breeds were the Miniature poodle, Bearded collie, Border collie and Miniature dachshund, while the shortest-lived were the Dogue de Bordeaux and Great Dane. The most frequently attributed causes of death were neoplastic, musculoskeletal and neurological disorders. The results of multivariable modelling indicated that longevity in crossbred dogs exceeded purebred dogs by 1.2 years (95% confidence interval 0.9-1.4; P<0.001) and that increasing bodyweight was negatively correlated with longevity. The current findings highlight major breed differences for longevity and support the concept of hybrid vigour in dogs.

Benzodiazepine exposure in pregnancy and risk of major malformations: a critical overview

OBJECTIVE

Benzodiazepines (BDZs) safety profiles in pregnancy suggest that the risk of major malformations (MMs) cannot be considered simply as a "class effect". The aim of this paper was to review and update the available literature on the risks of MMs in women exposed to BDZs in the first trimester of pregnancy.

METHODS

PubMed was searched for English-language articles, from January 2001 to November 2011, introducing as keywords "teratogens", " major malformation", "foetus", "infant", "newborn", "pregnancy", in conjunction with "benzodiazepines" as a keyword or BDZ generic name as text words.

RESULTS

Twelve studies were selected for the review. BDZ exposure during the first trimester of pregnancy seems not to be associated with an increasing risk of congenital MMs. Diazepam and chlordiazepoxide should be considered drugs of first choice.

CONCLUSIONS

Data published in the last 10 years did not indicate an absolute contraindication in prescribing BDZs during the first gestational trimester. In any case, studies analyzed suffer from a number of methodological limitations such as lack of careful report of BDZ patterns of use in pregnancy, possible influences of recall bias, lack of controlling for confounding factors and lack of data concerning possible MMs in aborted fetuses.

Miscarriage and occupational activity: a systematic review and meta-analysis regarding shift work, working hours, lifting, standing, and physical workload

OBJECTIVE

Previous studies have indicated that shift work, long working hours, and prevalent workplace exposures such as lifting, standing, and physical workload increase the risk of miscarriage, but the evidence is conflicting. We conducted a systematic review of original research reports.

METHODS

A search in Medline and EMBASE 1966-2012 identified 30 primary papers reporting the relative risk (RR) of miscarriage according to ≥1 of 5 occupational activities of interest. Following an assessment of completeness of reporting, confounding, and bias, each risk estimate was characterized as more or less likely to be biased. Studies with equivalent measures of exposure were pooled to obtain a weighted common risk estimate. Sensitivity analyses excluded studies most likely to be biased.

RESULTS

Working fixed nights was associated with a moderately increased risk of miscarriage (pooled RR 1.51 [95% confidence interval (95% CI) 1.27-1.78, N=5), while working in 3-shift schedules, working for 40-52 hours weekly, lifting >100 kg/day, standing >6-8 hours/day and physical workload were associated with small risk increments, with the pooled RR ranging from 1.12 (3-shift schedule, N=7) to 1.36 (working hours, N=10). RR for working hours and standing became smaller when analyses were restricted to higher quality studies.

CONCLUSIONS

These largely reassuring findings do not provide a strong case for mandatory restrictions in relation to shift work, long working hours, occupational lifting, standing, and physical workload. Considering the limited evidence base, however, it may be prudent to advise women against work entailing high levels of these exposures and women with at-risk pregnancies should receive tailored individual counseling.

Short-Term Oral Diazepam Treatment during Pregnancy : A Population-Based Teratological Case-Control Study

OBJECTIVE

To study the possible human teratogenicity of short-term (generally 3 weeks) oral diazepam treatment during pregnancy.

DESIGN AND SETTING

A matched case-population control pair analysis based on the total (maternal self-reported and medically recorded) or medically recorded diazepam treatments, in addition to a comparison between cases and patient controls in the population-based large data set of the Hungarian Case-Control Surveillance of Congenital Abnormalities from 1980 to 1996.

STUDY PARTICIPANTS

38 151 population-control neonates without any congenital abnormalities, 22 865 neonates or fetuses with congenital abnormalities (cases) and 812 neonates or fetuses with Down's syndrome (patient controls).

MAIN OUTCOME MEASURES

24 congenital abnormality groups.

RESULTS

2746 (12.0%) cases, 4130 (10.8%) population controls and 97 (11.9%) patient controls were born to mothers treated with diazepam during pregnancy. The matched case-population control pair analysis showed a higher rate of limb deficiencies, rectal-anal atresia/stenosis, cardiovascular malformations and multiple congenital abnormalities after diazepam use during the second and third months of gestation, i.e. in the critical period for most major congenital abnormalities, based on maternal self-reported and medically recorded information. However, the evaluation of only medically recorded diazepam use did not indicate a higher use of diazepam in any congenital abnormality group. Thus, the higher occurrence of diazepam treatment among cases in the primary analysis may be due to the lower proportion of maternal self-reported diazepam intake in the population control group, i.e. recall bias. The comparison of diazepam use between 24 congenital abnormality groups and patient controls as the referent group showed a difference only in the group of intestinal atresia/stenosis, probably due to chance error caused by multiple comparison.

CONCLUSIONS

Short-term diazepam treatment in usual therapeutic doses during pregnancy did not present any detectable teratogenic risk to the fetus.

Agreement between self-report and prescription data in medical records for pregnant women

BACKGROUND Clinical teratology studies often rely on patient reports of medication use in pregnancy with or without other sources of information. Electronic medical records (EMRs), administrative databases, pharmacy dispensing records, drug registries, and patients' self-reports are all widely used sources of information to assess potential teratogenic effect of medications. The objective of this study was to assess comparability of self-reported and prescription medication data in EMRs for the most common therapeutic classes. METHODS The study population included 404 pregnant women prospectively recruited from five prenatal care clinics affiliated with the University of New Mexico. Self-reported information on prescription medications taken since the last menstrual period (LMP) was obtained by semistructured interviews in either English or Spanish. For validation purposes, EMRs were reviewed to abstract information on medications prescribed between the LMP and the date of the interview. Agreement was estimated by calculating a kappa (κ) coefficient, sensitivity, and specificity. RESULTS In this sample of socially-disadvantaged (i.e., 67.9% high school education or less, 48.5% no health insurance), predominantly Latina (80.4%) pregnant women, antibiotics and antidiabetic agents were the most prevalent therapeutic classes. The agreement between the two sources substantially varied by therapeutic class, with the highest level of agreement seen among antidiabetic and thyroid medications (κ ≥0.8) and the lowest among opioid analgesics (κ = 0.35). CONCLUSIONS Results indicate a high concordance between self-report and prescription data for therapeutic classes used chronically, while poor agreement was observed for medications used intermittently, on an 'as needed" basis, or in short courses.

Inhaled glucocorticoids during pregnancy and offspring pediatric diseases: a national cohort study

RATIONALE

Glucocorticoid inhalation is the preferred asthma treatment during pregnancy. Previous studies on its safety focused on obstetric outcomes and offspring malformations.

OBJECTIVES

To determine whether glucocorticoid inhalation during pregnancy is a risk factor for offspring pediatric diseases.

METHODS

We studied offspring (live singletons) of pregnant women suffering from asthma during pregnancy (prevalence = 6.3%; n = 4,083 mother-child pairs) from the Danish National Birth Cohort (births, 1996-2002; prospective data). We estimated the associations between use of inhaled glucocorticoids for asthma treatment during pregnancy (n = 1231; 79.9% budesonide, 17.6% fluticasone, 5.4% beclomethasone, and 0.9% other or unspecified glucocorticoids) and offspring diseases (International Classification of Diseases-10th Revision, diagnoses) during childhood. We conducted Cox or logistic regression analyses for each International Classification of Diseases-10th Revision category, controlling for use of non-glucocorticoid-containing inhalants, and confirmed results by addressing confounding by treatment indication using propensity score.

MEASUREMENTS AND MAIN RESULTS

Offspring median age at end of follow-up was 6.1 (range, 3.6-8.9) years. Glucocorticoid inhalation was not associated with offspring disease risk in most categories, except for offspring endocrine, metabolic, and nutritional disorders (hazard ratio, 1.84; 95% confidence interval, 1.13-2.99). When repeating analyses with the major subgroup that used budesonide only, association estimates were of similar magnitude.

CONCLUSIONS

Regarding most disease categories, data are reassuring, supporting the use of inhaled glucocorticoids during pregnancy. In line with animal data, glucocorticoid inhalation during pregnancy may be a risk factor for offspring endocrine and metabolic disturbances, which should be considered further.

Maternal bronchodilator use and the risk of orofacial clefts

BACKGROUND

Few epidemiological studies have explored the relationship between orofacial clefts and bronchodilators. We assessed whether mothers who used bronchodilators during early pregnancy were at an increased risk of delivering infants with orofacial clefts.

METHODS

We used National Birth Defects Prevention Study case-control data from mothers of 2711 infants with orofacial clefts and 6482 mothers of live born infants without birth defects, delivered during 1997 through 2005. Information on medication use from 3 months before pregnancy through delivery was collected using a standardized interview. Logistic regression was used to estimate adjusted odds ratios (aOR) and 95% confidence intervals (CIs) for maternal bronchodilator use during the periconceptional period (1 month before pregnancy through the third month of pregnancy) while controlling for other covariates.

RESULTS

We observed an association between maternal bronchodilator use during the periconceptional period and cleft lip only (CLO) (aOR = 1.77, 95% CI: 1.08-2.88). The risk of cleft palate only (CPO) (aOR = 1.53, 95% CI: 0.99-2.37) was elevated but was not statistically significant. No association was observed for maternal bronchodilator use and the risk of cleft lip with cleft palate (aOR = 0.78, 95% CI: 0.46-1.31). The most commonly used bronchodilator was albuterol (88.7%). Maternal albuterol use was associated with CLO (aOR = 1.79, 95% CI: 1.07-2.99) and CPO (aOR = 1.65, 95% CI: 1.06-2.58).

CONCLUSIONS

We observed a statistically significant association between maternal bronchodilator use during the periconceptional period and the risk of CLO after controlling for other risk factors. It is unclear whether the increased odds ratios observed in this study are due to the bronchodilators, the severity of asthma, or both, or to chance alone. Further studies to disentangle the role of asthma or asthma medications would help clarify these findings.

Evaluation of the representativeness of a Dutch non-malformed control group for the general pregnant population: are these controls useful for EUROCAT?

PURPOSE

A case-control study is the most powerful design to test the risk of specific congenital malformations associated with a specific drug. However, malformation registries often lack non-malformed controls. For the Dutch EUROCAT, we collected a non-malformed control group: the 'Healthy Pregnant'. The aim of this study was to evaluate the representativeness of this control group for the general pregnant population in the northern part of the Netherlands.

METHODS

The Healthy Pregnant data set includes data from two midwife practices. The baseline characteristics of mother and child including smoking status, drinking status, body mass index, maternal age, educational level, exposures to several drugs for chronic diseases and pregnancy related symptoms were evaluated.

RESULTS

Compared with the general population, mothers in Healthy Pregnant group (n = 556) were from either low or high education level, were more likely to have a body mass index > 25 kg/m² (26% versus 22%, p = 0.08) or to smoke (19% versus 10%, p < 0.01) but were less likely to consume alcohol (20% versus 29%, p < 0.01). The use of drugs for chronic conditions was lower in Healthy Pregnant group. Furthermore, drugs for occasional use were prescribed less frequently, and a significant underreporting of children with a low birth weight and a short duration of gestation was found.

CONCLUSION

The Healthy Pregnant data set was not representative of the general pregnant population in the northern part of the Netherlands. Specifically, the exposure to (chronic) drugs was underestimated, possibly a result of second-line care on the basis of medical indication. Thus, continuous investigation of options for improvement of the Healthy Pregnant database is required.

Interpretation of controversial teratogenic findings of drugs such as phenobarbital

Objective. To check the debated association between phenobarbital treatment during pregnancy and risk for congenital abnormalities (CAs) in their children. Study Design. It is a comparison of phenobarbital treatment in the mothers of cases with CA and matched controls without CAs in the Hungarian Case-Control Surveillance System of Congenital Abnormalities. Results. Of 22,843 cases with CA, 149 (0.65%) had mothers with phenobarbital treatment, while of 38,151 control newborn infants without CA, 209 (0.55%) were born to mothers with phenobarbital treatment (100-400 mg daily) (OR with 95% CI : 1.3, 1.1-1.7). Of 16 CA groups, only hypospadias had a higher risk after phenobarbital treatment in the critical period of this CA (OR with 95% CI : 2.4, 1.1-5.4). However, if only medically recorded phenobarbital treatments were evaluated and multiple testing bias was considered, this association would disappear. Conclusions. This study stresses the importance of the exclusion of recall bias and multiple testing bias.

Association of drug treatments in pregnant women with the risk of external ear congenital abnormalities in their offspring: a population-based case-control study

The objective of this study was to evaluate the possible association of drug treatments in pregnant women with a higher risk of congenital abnormalities of the external ear, particularly microtia/anotia, in their children. The frequency of drug treatments was compared in the mothers of cases with isolated or multiple (syndromic) ear abnormalities and in the mothers of three different controls: controls matched to cases, all controls (these controls had no defects) and malformed controls in the population-based large dataset of the Hungarian Case-Control Surveillance of Congenital Abnormalities. There was no significantly higher use of any drug in the mothers of 354 cases with isolated external ear abnormalities than in the mothers of different controls. However, of 156 cases with multiple ear abnormalities, 11 had mothers with hydroxyethylrutosidea treatment and a characteristic pattern of congenital abnormalities was found in these children. Four cases with multiple ear abnormalities were born to epileptic mothers treated with valproate, phenytoin and polytherapy in two cases. Drug treatments are not important in the origin of isolated ear abnormalities. However, a higher risk of multiple ear abnormalities was found in children born to mothers with treatment of hydroxyethylrutosidea or antiepileptic drugs during pregnancy.

No association of maternal vitamin E intake with higher risk of cardiovascular malformations in children: a population-based case-control study

OBJECTIVE

In Hungary, vitamin E is frequently used to prevent repeated or threatened abortion. A previous study showed a higher risk of cardiovascular malformations in the children of pregnant women who had a high vitamin E intake either in their diet or by taking supplements. The objective was to examine this association.

METHODS

The Hungarian Case-Control Surveillance System of Congenital Abnormalities, 1980-1996, is a large, population-based dataset including 22,843 cases with congenital abnormalities, 38,151 healthy controls matched to the cases, and 834 patient controls with Down syndrome. Vitamin E treatment was compared in the mothers of these children.

RESULTS

The mothers of 1418 cases with congenital abnormalities (6.2%), 2267 controls (6.0%) and 43 patient controls (5.2%) had vitamin E treatment during pregnancy. A preliminary comparison of cases and controls showed a higher risk for four congenital abnormality groups, including cardiovascular malformations. However, if only prospectively and medically recorded vitamin E treatments in the prenatal maternity logbook were evaluated during the critical period of different congenital abnormalities, the higher risk for these congenital abnormalities was not found.

CONCLUSIONS

The results of this study were based on relatively high-dose vitamin E intake in pregnant women and were not able to confirm the previously reported teratogenic effect of vitamin E.

Medication use during pregnancy in Omani women

OBJECTIVE

The aim of this study was to evaluate medication use pattern in a university tertiary hospital in the Sultanate of Oman.

SETTING

The study was conducted at the Sultan Qaboos University Hospital (SQUH) and the SQUH Family and Community Medicine clinic (FAMCO), Muscat, Sultanate of Oman during 7th to 25th June 2008.

METHOD

The medication use pattern was evaluated in women attending FAMCO and the standard antenatal clinics at the hospital. Women were interviewed in different gestational ages using a structured questionnaire. The Electronic Patient Record (EPR) was reviewed to acquire additional information on medication use. Medications were classified according to the US FDA risk classification.

MAIN OUTCOME MEASURE

Medication used including prescribed medications, OTC medications, or herbal treatment during the current pregnancy and 3 months prior to conception.

RESULTS

The study included a total of 139 pregnant mothers with an overall mean age of 28 ± 5 years ranging from 19 to 45 years. There was a slight overall reduction in the medication use including prescribed medications. However, there was a significant increase in utilization of vitamins and supplements (84-95% vs. 12% in the 3-months prior, P < 0.001) as well as herbal preparations (16-19% vs. 7% in the 3-months prior, P = 0.011) throughout pregnancy (P < 0.010). The use of category A medications increased in all trimester (43-52% vs. 13% in the 3 months prior, P < 0.010) while a reduction in the use of category C (for first and third trimester, P < 0.050) and D medications was seen. A reduction in the use of teratogenic drugs in all trimesters (P < 0.010) was also observed.

CONCLUSION

The prescribing of vitamins and minerals was optimal. However, the common use of herbal supplements observed warrants special attention due to their unknown risks. The conclusions should be interpreted in light of the study's limitations.

Peptic ulcer disease with related drug treatment in pregnant women and congenital abnormalities in their offspring

Peptic ulcer disease (PUD) is a common disease which can also occur in pregnant women. However, the possible association of PUD and related drug treatments in pregnant women with the risk of structural birth defects (i.e. congenital abnormalities [CA]) in their offspring has not been estimated in controlled population-based epidemiological studies. Thus, the prevalence of PUD in pregnant women who later delivered babies (cases) with different CA and in pregnant women who delivered newborns without CA (controls) was compared in the Hungarian Case-Control Surveillance of Congenital Abnormalities. Controls were matched to cases. Of 22,843 cases with congenital abnormalities, 182 (0.80%) had mothers with reported/recorded PUD, while of 38,151 controls, 261 (0.68%) were born to mothers with reported/recorded PUD. However, PUD(?) based on maternal information and/or unspecified diagnostic criteria, and PUD(!) based on endoscopic diagnosis showed different variables of mothers and newborn infants. Thus, finally, 20 case mothers and 58 control mothers with PUD(!) and related drugs were evaluated in detail. There was no higher risk for total CA group in the offspring of mothers with PUD during pregnancy (adjusted OR with 95% CI: 0.6, 0.3-0.9). Specific CA groups in cases were also assessed versus controls, but specified CA had no higher risk in the offspring of pregnant women with PUD and related drug treatments. In conclusion, a higher rate of CA was not found in the offspring of mothers with PUD.

Maternal use of antibiotics and cancer in the offspring: results of a case-control study in Germany

OBJECTIVE

As previous results were inconsistent, we assessed the association between maternal use of antibiotics during pregnancy or 3 months before conception and childhood cancer in the offspring in a large case-control study in Germany.

METHODS

This population-based study on potential risk factors for childhood cancer was conducted by the German Childhood Cancer Registry (GCCR) and included a total of 1,867 registered cancer cases aged 0-14, diagnosed between October 1992 and September 1994. A total of 2,057 controls were randomly drawn from population registries, matched by age, gender, and region. Conditional logistic regression models for frequency-matched datasets were used to estimate odds ratios (OR) with 95% confidence intervals (95% CI).

RESULTS

Positive statistically significant associations with self-reported maternal antibiotic use were observed for acute lymphoid leukemia (based on 59 mothers exposed to antibiotics, OR = 1.47; 95% CI: 1.06-2.04), acute myeloid leukemia (18 exposed, OR = 3.21; 95% CI: 1.83-5.62), and Burkitt lymphoma (three exposed, OR = 5.89; 95% CI: 1.47-23.69), but not other cancer types.

CONCLUSIONS

The results provide some support for the hypothesis that maternal use of antibiotics increases the risk of cancer in the offspring. Although recall bias is a concern, it is unlikely that this fully explains the observed effect. Further, the observed associations might be related to the underlying infections.

Paracetamol use in early life and asthma: prospective birth cohort study

OBJECTIVE

To determine if use of paracetamol in early life is an independent risk factor for childhood asthma.

DESIGN

Prospective birth cohort study.

SETTING

Melbourne Atopy Cohort Study.

PARTICIPANTS

620 children with a family history of allergic disease, with paracetamol use prospectively documented on 18 occasions from birth to 2 years of age, followed until age 7 years.

MAIN OUTCOME MEASURES

The primary outcome was childhood asthma, ascertained by questionnaire at 6 and 7 years. Secondary outcomes were infantile wheeze, allergic rhinitis, eczema, and skin prick test positivity.

RESULTS

Paracetamol had been used in 51% (295/575) of children by 12 weeks of age and in 97% (556/575) by 2 years. Between 6 and 7 years, 80% (495/620) were followed up; 30% (148) had current asthma. Increasing frequency of paracetamol use was weakly associated with increased risk of childhood asthma (crude odds ratio 1.18, 95% confidence interval 1.00 to 1.39, per doubling of days of use). However, after adjustment for frequency of respiratory infections, this association essentially disappeared (odds ratio 1.08, 0.91 to 1.29). Paracetamol use for non-respiratory causes was not associated with asthma (crude odds ratio 0.95, 0.81 to 1.12).

CONCLUSIONS

In children with a family history of allergic diseases, no association was found between early paracetamol use and risk of subsequent allergic disease after adjustment for respiratory infections or when paracetamol use was restricted to non-respiratory tract infections. These findings suggest that early paracetamol use does not increase the risk of asthma.

Medical databases in studies of drug teratogenicity: methodological issues

More than half of all pregnant women take prescription medications, raising concerns about fetal safety. Medical databases routinely collecting data from large populations are potentially valuable resources for cohort studies addressing teratogenicity of drugs. These include electronic medical records, administrative databases, population health registries, and teratogenicity information services. Medical databases allow estimation of prevalences of birth defects with enhanced precision, but systematic error remains a potentially serious problem. In this review, we first provide a brief description of types of North American and European medical databases suitable for studying teratogenicity of drugs and then discuss manifestation of systematic errors in teratogenicity studies based on such databases. Selection bias stems primarily from the inability to ascertain all reproductive outcomes. Information bias (misclassification) may be caused by paucity of recorded clinical details or incomplete documentation of medication use. Confounding, particularly confounding by indication, can rarely be ruled out. Bias that either masks teratogenicity or creates false appearance thereof, may have adverse consequences for the health of the child and the mother. Biases should be quantified and their potential impact on the study results should be assessed. Both theory and software are available for such estimation. Provided that methodological problems are understood and effectively handled, computerized medical databases are a valuable source of data for studies of teratogenicity of drugs.

Teratogenic potential of pholedrine: a sympathomimetic vasoconstrictive drug - a population-based case-control study

Pholedrine was a frequently used drug for the treatment of severe hypotension in some countries, including Hungary. The possible teratogenic effect of pholedrine was not checked; therefore; the birth outcomes, particularly congenital abnormalities (CAs), of infants born to women treated with pholedrine during pregnancy, and pregnancy complications were evaluated in the population-based large dataset of the Hungarian Case-Control Surveillance System of Congenital Abnormalities. Cases with CA and their matched controls without CA born to mothers with pholedrine use during pregnancy were compared. Of 22 843 cases and 38 151 controls, 768 (3.4%) and 1509 (4.0%) were born to mothers with pholedrine treatment, respectively (adjusted odds ratios [OR] with 95% CI: 0.9, 0.8-1.0). There was no higher risk for any CA group in the offspring of mothers who used pholedrine during the second and/or third month of pregnancy (i.e. the critical period of most major CA). The mean gestational week at delivery and birthweight was similar in newborns of women with or without pholedrine treatment during pregnancy. The pattern of pregnancy complications was characteristic (lower incidence of preeclampsia/eclampsia, while higher incidence of severe nausea/vomiting and anemia), explained mainly by the underlying maternal hypotension. In conclusion, pholedrine treatment in pregnant women was not associated with a higher risk for CA or other adverse birth outcomes, such as preterm birth or low birthweight. The knowledge of the teratogenic potential of pholedrine may contribute to the evaluation of other sympathomimetic drugs.

A successful implementation of e-epidemiology: the Danish pregnancy planning study 'Snart-Gravid'

The attraction of being able to use the internet for the recruitment of an epidemiologic cohort stems mainly from cost efficiency and convenience. The pregnancy planning study ('Snart-Gravid')-a prospective cohort study of Danish women planning a pregnancy-was conducted to evaluate the feasibility and cost efficiency of using internet-based recruitment and follow-up. Feasibility was assessed by examining patient accrual data over time, questionnaire-specific response rates and losses to follow-up. The relative cost efficiency was examined by comparing the study costs with those of an alternative non internet-based study approach. The target recruitment of 2,500 participants over 6 months was achieved using advertisements on a health-related website, supported by a coordinated media strategy at study initiation. Questionnaire cycle-specific response rates ranged from 87 to 90% over the 12-month follow-up. At 6 months, 87% of women had a known outcome or were still under follow-up; at 12 months the figure was 82%. The study cost of $400,000 ($160 per enrolled subject) compared favorably with the estimated cost to conduct the same study using a conventional non-internet based approach ($322 per subject). The gain in efficiency with the internet-based approach appeared to be even more substantial with longer follow-up and larger study sizes. The successful conduct of this pilot study suggests that the internet may be a useful tool to recruit and follow subjects in prospective cohort studies.

Accuracy of reporting bleeding during pregnancy

Vaginal bleeding during pregnancy has been considered a marker of an at-risk pregnancy, but the accuracy of reported bleeding has not been assessed. We sought to evaluate the agreement in vaginal bleeding reports based on prospective daily diary and retrospective recall at first-trimester interview and to investigate predictors of reporting accuracy. Participants recruited prior to pregnancy for a community-based pregnancy cohort (n = 153) completed web-based daily diaries beginning before pregnancy until the end of the first trimester. A comprehensive first-trimester interview was conducted, and the bleeding data from diary and interview were compared. Kappa statistics were used to quantify agreement. Log-linear models were used to investigate maternal age, prior miscarriage, and current pregnancy outcome as potential predictors of agreement. We found that bleeding characteristics (number of bleeding episodes, bleeding heaviness, duration and gestational timing) from the diary and interview were reported with high levels of agreement. Kappas ranged from 0.77 to 0.84. Retrospective report of any bleeding had a sensitivity of 0.80 and specificity of 1.0; however, sensitivity was lower when examined within smaller time intervals. Important predictors of agreement were not identified in this analysis, but the sample was small. Overall, the presence of vaginal bleeding, a common and potentially alarming symptom of early pregnancy, may be assessed by interview later in pregnancy with reasonable accuracy.

Oral clefts, consanguinity, parental tobacco and alcohol use: a case-control study in Rio de Janeiro, Brazil

This hospital-based, case-control study investigated the possible associations between family history of malformations, parental consanguinity, smoking and alcohol drinking and nonsyndromic orofacial cleft (OC, subdivided in 2 main groups: CL/P - cleft lip with or without cleft palate and CP - cleft palate alone). 274 cases were matched (age, sex and place of residence) to 548 controls. Odds ratios (OR) and 95% confidence intervals (95% CI) - adjusted for maternal age, schooling and smoking / alcohol use - were calculated by conditional logistic regression. The results demonstrated that the history of oral clefts either in the father's (CL/P: OR = 16.00, 5.64-69.23; CP: OR = 6.64, 1.48-33.75) or in the mother's family (CL/P: OR = 5.00, 2.31-10.99, CP: OR = 12.44, 1.33-294.87) was strongly associated with both types of clefts, but parental consanguinity was associated only with CL/P (OR = 3.8, 1.27-12.18). Prevalence of maternal smoking during the first trimester of pregnancy was higher among cases but the OR (1.13, 0.81-1.57) was not statistically significant. Maternal passive smoking (nonsmoking mothers) during pregnancy was associated with CL/P (1.39, 1.01-1.98) but not with CP. Maternal alcohol use during the 1st trimester increased odds for CL/P (OR = 2.08, 1.27-3.41) and CP (OR = 2.89, 1.25-8.30), and odds for OC tended to increase with dose. Neither smoking nor alcohol use by fathers increased risks for OC. This study provides further evidence of a possible role of maternal exposure to tobacco smoke and alcohol in the etiology of nonsyndromic oral clefts.

Oral impacts on daily performances: associations with self-reported general health and medication

OBJECTIVE

The aim of the present study was to examine the impact of general diseases and medication on oral health-related quality of life (OHRQoL) in a Swedish adult population using the Swedish version of Oral Impacts on Daily Performances (OIDP).

MATERIAL AND METHODS

A three-site sample of 200 adults (20-86 years; participation rate 70%) was interviewed using the OIDP, and a medical anamnesis was performed in 2006-7. A self-reported questionnaire provided complementary socio-economic data.

RESULTS

The burden of medical diagnoses and medications was greatest among the older participants in the study. The mean number of medicines in regular users was: ≥60 years, 3.6 (SD 2.6); 40-59 years, 1.9 (SD 1.5); and 20-40 years, 1.9 (SD 1.8) (p =0.013). There were no gender differences in general health or medication variables. Self-reported health, medical diagnoses and medication were significantly and consistently associated with the OIDP score: subjects with ≥1 diagnosis, OR 2.22 (95% CI 1.19-4.14) and subjects with ≥1 medicines, OR 1.85 (95% CI 1.01-3.40) versus those without diagnoses or medication. However, there was a clear gradient: OIDP scores increased with increasing numbers of diagnoses and medicines.

CONCLUSION

The Swedish version of the OIDP was found useful for measuring impacts of general health and medication on OHRQoL. Dental care should pay special attention to patients with medical conditions or who are on medication, because these patients are more likely to experience oral impacts on daily performances.

A Population-Based Case-Control Study of Isolated Ocular Coloboma

AIMS

To attempt the detection of possible etiological factors in the origin of isolated ocular, mainly iris coloboma.

METHODS

The data set of the Hungarian Case-Control Surveillance of Congenital Abnormalities, 1980-2002, was used. Exposure data and family history were based on (1) prospective medical records, (2) retrospective maternal information, and (3) information obtained by regional nurses at home visit.

RESULTS

Of 46 cases, 40 were affected with iris coloboma and 19 had bilateral manifestation. The positive family history indicated a hereditary origin in 4.3% (2/46) of cases. An association was found between the isolated ocular coloboma and hydroxyethylrutoside treatment (adjusted POR with 95% CI: 5.4, 2.2-12.9). Another association was seen between isolated ocular coloboma and hypothyroidism (adjusted OR with 95% CI = 12.6, 3.0-52.7), but it was based only on two cases.

CONCLUSIONS

It is necessary to study the preventable environmental factors in the origin of these ocular defects.

A Population-based Case-control Teratological Study of Oral Nystatin Treatment During Pregnancy

The aim of the study was to investigate the teratogenicity of oral nystatin treatment during pregnancy in the population-based data set of the Hungarian Case-Control Surveillance of Congenital Abnormalities between 1980 and 1996. In total, 38,151 pregnant women who delivered newborn infants without any defects (control group) and 22,843 pregnant women who had foetuses or newborns with congenital abnormalities (CA) (case group) were included in the study. 106 (0.5%) case and 143 (0.4%) control pregnant women were treated with oral nystatin (crude OR with 95% CI = 1.2, 1.0-1.6). A teratogenic potential of nystatin was seen in 1 CA-group (hypospadias) in 2 different approaches of the study (case-control and total control--CA groups comparison) during the critical period of this congenital abnormality. The conclusion of the study is that treatment with oral nystatin during pregnancy presents little teratogenic risk to the foetus, but the possible association between hypospadias and nystatin needs further study.

Antihypertensive medication use during pregnancy and the risk of cardiovascular malformations

We used data from the National Birth Defects Prevention Study, a population-based, case-control study, to examine whether previously reported associations between antihypertensive medications and cardiovascular malformations could be confirmed and to explore whether new associations might be identified. Cases (n=5021) were ascertained through birth defects surveillance systems from 1997 through 2003 in 10 US states. Controls (n=4796) were live births without birth defects selected randomly from birth certificates or hospital discharge listings in the same geographic regions. Logistic regression was used to examine the relationship between antihypertensive medication treatment and the occurrence of cardiovascular malformations while controlling for confounding variables. First-trimester treatment with antihypertensive medication was associated with pulmonary valve stenosis (odds ratio [OR]: 2.6; 95% CI: 1.3 to 5.4), Ebstein malformation (crude OR: 11.4; exact 95% CI: 2.8 to 34.1), coarctation of the aorta (OR: 3.0; 95% CI: 1.3 to 6.6), and secundum atrial septal defects (OR: 2.4; 95% CI: 1.3 to 4.4). Treatment initiated after the first trimester was associated with pulmonary valve stenosis (OR: 2.4; 95% CI: 1.1 to 5.4), perimembranous ventricular septal defects (OR: 2.3; 95% CI: 1.2 to 4.6), and secundum atrial septal defects (OR: 2.4; 95% CI: 1.3 to 4.4). Untreated hypertension was associated with Ebstein malformation (OR: 2.1; 95% CI: 1.0 to 4.3) and secundum atrial septal defects (OR: 1.3; 95% CI: 1.0 to 1.6). Antihypertensive medication use and/or the underlying hypertension might increase the risk of having an infant with specific left and right obstructive and septal defects. Additional studies with adequate power will be needed to confirm these findings.

Birth outcomes of cases with unclassified multiple congenital abnormalities and pregnancy complications in their mothers depending on the number of component defects. Population-based case-control study

Multiple congenital abnormalities (MCA) represent the most severe category of structural birth defects, (i.e. congenital abnormalities [CA]). Unfortunately, most MCA are not recognized and/or identified as MCA syndromes or MCA associations in the clinical practice. The term unclassified MCA (UMCA) is used for this category of MCA. We decided to evaluate the component CA of UMCA cases. The population-based large dataset of the Hungarian Case-Control Surveillance of Congenital Abnormalities (1980-1996) was evaluated. 'False' MCA, such as complex CA, polytopic field defects and sequences were excluded from the category of MCA. In addition, MCA syndromes caused by chromosomal aberrations and major mutant genes with preconceptional origin were excluded from the dataset of the Surveillance. MCA syndromes caused by teratogens and MCA associations with well-defined component CA were also excluded in the study. Thus, only UMCA cases (i) without the recognition of previously delineated MCA syndromes (ii) and/or without the identification of new MCA syndromes or (iii) caused by random combination of CA were included in the study. We compared data from 1349 cases with UMCA, 2405 matched population controls without any CA, and 21 494 malformed controls with isolated CA. There was a higher rate of stillbirth and a moderate male excess in UMCA cases, a somewhat shorter gestational age at delivery and an obvious reduction in birthweight. The intrauterine fetal growth retardation and rate of low-birthweight newborns showed an association with the number of component CA in UMCA cases. A similar association was not found with gestational age and the rate of preterm birth. UMCA represent one of the most severe categories of CA. The degree of intrauterine fetal growth retardation depends on number of component CA in UMCA cases.

Drug-prescribing patterns during pregnancy in the tertiary care hospitals of Pakistan: a cross sectional study

Background

The rationale for use of drugs during pregnancy requires a careful assessment as in addition to the mother, the health and life of her unborn child is also at stake. Information on the use of drugs during pregnancy is not available in Pakistan. The aim of this study was to evaluate the patterns of drug prescriptions to pregnant women in tertiary care hospitals of Pakistan.

Methods

This was a cross-sectional study conducted at five tertiary care hospitals of Pakistan. Copies of outpatient medicinal prescriptions given to pregnant patients attending the antenatal clinics were collected. The drugs were classified according to the pharmacological class and their teratogenic potential.

Results

All the pregnant women attending the antenatal clinics received a prescription containing at least one drug. A total of 3769 distinct prescriptions given to different women were collected. Majority of the women who received the prescriptions belonged to third trimester (55.4%) followed by second (33.6%) and first trimester (11.0%). On an average, each prescription contained 1.66 ± 0.14 drugs. The obstetricians at Civil Hospital, Karachi and Chandka Medical College Hospital, Larkana showed a tendency of prescribing lesser number of drugs compared to those in other hospitals. Anti-anemic drugs including iron preparations and vitamin and mineral supplements (79.4%) were the most frequently prescribed drugs followed by analgesics (6.2%) and anti-bacterials (2.2%). 739 women (19.6%) received prescriptions containing drugs other than vitamin or mineral supplements. Only 1275 (21.6%) of all the prescribed drugs (n = 6100) were outside this vitamin/mineral supplement class. Out of these 1275 drugs, 29 (2.3%) drugs were prescribed which are considered to be teratogenic. Misoprostol was the most frequently prescribed (n = 6) among the teratogenic drugs followed by carbimazole (n = 5) and methotrexate (n = 5). Twenty nine pregnant women (0.8% of all the women studied) were prescribed these teratogenic drugs.

Conclusion

Less than one percent of the pregnant women attending tertiary care hospitals in Pakistan are prescribed teratogenic drugs. The prescribing practices of Pakistani physicians are similar to those in western countries.

Risk of miscarriage for pregnant users of pivmecillinam: a population-based case-control study

Few data exist on the risk of miscarriage after exposure to pivmecillinam. We therefore conducted a population-based case-control study in a Danish county with 0.5 million inhabitants during the period 1997-2002. We included 1,599 women with a miscarriage recorded in the Hospital Discharge Registry and selected 10 controls per case among primiparous women who had a live birth during the study period. Controls were selected from the Danish Medical Birth Registry. We obtained data on use of pivmecillinam and sulfamethizole from a prescription database. Five cases (0.30%) and 24 controls (0.15%) were exposed to pivmecillinam in the last week before the miscarriage/index date. After adjustment for maternal age, use of antidiabetics or antiepileptics, the odds ratio for miscarriages among users of pivmecillinam compared with non-users was 2.03 (95% confidence interval: 0.77-5.33) and the corresponding odds ratio for use of sulfamethizole was 1.53 (95% confidence interval: 0.76-3.09). Exposure within 2 to 12 weeks before the miscarriage was not associated with an increased risk. We concluded that use of pivmecillinam was associated with an increased risk of miscarriage, but the risk was not significantly (p=0.64) different from the risk associated with use of sulfamethizole.

Risk of miscarriage for pregnant users of pivmecillinam: a population-based case-control study

Few data exist on the risk of miscarriage after exposure to pivmecillinam. We therefore conducted a population-based case-control study in a Danish county with 0.5 million inhabitants during the period 1997-2002. We included 1,599 women with a miscarriage recorded in the Hospital Discharge Registry and selected 10 controls per case among primiparous women who had a live birth during the study period. Controls were selected from the Danish Medical Birth Registry. We obtained data on use of pivmecillinam and sulfamethizole from a prescription database. Five cases (0.30%) and 24 controls (0.15%) were exposed to pivmecillinam in the last week before the miscarriage/index date. After adjustment for maternal age, use of antidiabetics or antiepileptics, the odds ratio for miscarriages among users of pivmecillinam compared with non-users was 2.03 (95% confidence interval: 0.77-5.33) and the corresponding odds ratio for use of sulfamethizole was 1.53 (95% confidence interval: 0.76-3.09). Exposure within 2 to 12 weeks before the miscarriage was not associated with an increased risk. We concluded that use of pivmecillinam was associated with an increased risk of miscarriage, but the risk was not significantly (p=0.64) different from the risk associated with use of sulfamethizole.

Father's occupational exposure to carcinogenic agents and childhood acute leukemia: a new method to assess exposure (a case-control study)

Background

Medical research has not been able to establish whether a father's occupational exposures are associated with the development of acute leukemia (AL) in their offspring. The studies conducted have weaknesses that have generated a misclassification of such exposure. Occupations and exposures to substances associated with childhood cancer are not very frequently encountered in the general population; thus, the reported risks are both inconsistent and inaccurate. In this study, to assess exposure we used a new method, an exposure index, which took into consideration the industrial branch, specific position, use of protective equipment, substances at work, degree of contact with such substances, and time of exposure. This index allowed us to obtain a grade, which permitted the identification of individuals according to their level of exposure to known or potentially carcinogenic agents that are not necessarily specifically identified as risk factors for leukemia. The aim of this study was to determine the association between a father's occupational exposure to carcinogenic agents and the presence of AL in their offspring.

Methods

From 1999 to 2000, a case-control study was performed with 193 children who reside in Mexico City and had been diagnosed with AL. The initial sample-size calculation was 150 children per group, assessed with an expected odds ratio (OR) of three and a minimum exposure frequency of 15.8%. These children were matched by age, sex, and institution with 193 pediatric surgical patients at secondary-care hospitals. A questionnaire was used to determine each child's background and the characteristics of the father's occupation(s). In order to determine the level of exposure to carcinogenic agents, a previously validated exposure index (occupational exposure index, OEI) was used. The consistency and validity of the index were assessed by a questionnaire comparison, the sensory recognition of the work area, and an expert's opinion.

Results

The adjusted ORs and 95% confidence intervals (CI) were 1.69 (0.98, 2.92) during the preconception period; 1.98 (1.13, 3.45) during the index pregnancy; 2.11 (1.17, 3.78) during breastfeeding period; 2.17 (1.28, 3.66) after birth; and 2.06 (1.24, 3.42) for global exposure.

Conclusion

This is the first study in which an OEI was used to assess a father's occupational exposure to carcinogenic agents as a risk factor for the development of childhood AL in his offspring. From our results, we conclude that children whose fathers have been exposed to a high level of carcinogenic agents seem to have a greater risk of developing acute leukemia. However, confounding factors cannot be disregarded due to an incomplete control for confounding.

A population-based case-control teratologic study of promethazine use during pregnancy

Objective of the study was to investigate the teratogenic effect of oral promethazine, a phenothiazine derivate in the population-based data set of the Hungarian Case-Control Surveillance of Congenital Abnormalities during the years 1980-1996. Of 22,843 cases with 25 congenital abnormalities, 3648 (16.0%) were born to mothers treated orally with promethazine during pregnancy. Of 38,151 matched population controls without congenital abnormalities, 6025 (15.8%) had mothers with promethazine treatment during the study pregnancy. Of 834 malformed controls (Down syndrome), 142 (17.0%) had mothers with treatment of promethazine in the study pregnancy. The case-all matched population controls analysis showed a higher rate of cleft lip+/-cleft palate (adjusted OR with 95% CI: 1.5, 1.1-2.0) and poly/syndactyly (OR with 95% CI: 1.3, 1.0-1.8) after promethazine treatment during the 2nd and 3rd months of gestation. However, these risks were explained by recall bias, because these associations were not confirmed after the evaluation of only medically recorded promethazine uses. The comparison of promethazine treatment between 25 congenital abnormality groups and malformed controls did also not show any risk. Thus, the overall evidence from analysis presented did not suggest that clinical doses of promethazine increased the rate of congenital abnormalities in humans.

High fever-related maternal diseases as possible causes of multiple congenital abnormalities: a population-based case-control study

BACKGROUND

Multiple congenital abnormalities (MCAs) represent the most severe category of structural birth defects; therefore, we decided to evaluate the possible etiological factors for MCAs.

METHODS

The population-based large data set of the Hungarian Case-Control Surveillance of Congenital Abnormalities (1980-1996) was evaluated.

RESULTS

We compared the data of 1,349 cases with MCAs, 2,405 matched population controls without any defect, and 21,494 malformed controls with isolated congenital abnormalities. An association was found between a higher risk for MCAs and high fever-related influenza, common cold with secondary complications, tonsillitis, and recurrent orofacial herpes (adjusted ORs with 95% CIs: 2.3, 1.8-2.9). However, the risk for MCAs was reduced by antifever drug therapy (adjusted OR with 95% CI: 1.6, 0.9-2.9).

CONCLUSIONS

An association was found between high fever-related maternal diseases and a higher risk for MCAs; however, a certain portion of these MCAs is preventable by antifever therapy.

Population-based case-control study of the common cold during pregnancy and congenital abnormalities

The common cold is the most frequent maternal disease during pregnancy. The possible association between different congenital abnormalities and the common cold in pregnant women was evaluated in the data set of the Hungarian Case-Control Surveillance of Congenital Abnormalities between 1980 and 1996. Of 22,843 cases with congenital abnormalities, 3,827 (16.8%) had mothers with the common cold, while of 38,151 population controls without congenital abnormalities, 5,475 (14.4%) (adjusted prevalence odds ratio: POR: 1.26 with 95% CI: 1.20-1.32). Of 834 malformed controls with Down syndrome, 114 (17.3%) had mothers with the common cold (POR: 0.96 with 95% CI: 0.80-1.16). Nearly half of mothers with the common cold had secondary complications with antifever therapy. The comparison of cases with 25 congenital abnormalities and population control mothers with medically recorded common cold during the second and third months of gestation showed that five congenital abnormality groups: congenital hydrocephaly (3.6, 1.3-9.7), cleft lip+/-palate (2.3, 1.5-3.6), posterior cleft palate (2.3, 1.2-4.1), limb deficiencies (2.2, 1.1-4.1) and multiple CAs (2.0, 1.4-2.9) had adjusted POR 2 or more. The comparison of cases with different congenital abnormalities and malformed controls (including offspring with Down syndrome) as referent, indicated a higher prevalence of the common cold during the second and third month of gestation only in the mothers of cases with cleft lip+/-palate (adjusted POR: 1.7 with 95% CI: 1.2-2.5), however, congenital hydrocephaly, neural-tube defects and multiple CAs had also mothers with a somewhat higher occurrence of the common cold. The possible association between the common cold during early pregnancy and the above mentioned congenital abnormalities may be connected mainly with the indirect effect of secondary complications of maternal common cold, particularly high fever because antifever drugs were able to prevent the possible teratogenic effect of the common cold.

Selection of controls in case-control studies on maternal medication use and risk of birth defects

BACKGROUND

In case-control studies on teratogenic risks of maternal drug use during pregnancy, the use of normal or malformed controls may lead to recall-bias or selection bias. This can be avoided by using controls with a genetic disorder. However, researchers are hesitant to use these as controls because it is unknown whether their selection is independent of exposure status. The aim of this study is to investigate whether first trimester drug use among mothers of children with genetic disorders is representative for the "general pregnant population".

METHODS

From a birth defects registry 565 mothers of infants with a genetic disorder born between 1998-2004 were selected (the "genetic population"). The first trimester exposure rate was calculated for prescription-only drugs as the number of exposed women per 100. By calculating the rate ratio (RR) and 95% CI, the exposure rates in the genetic population were compared with those in the "source population" obtained from a population-based prescription database and consisting of 10,870 mothers who gave birth to a child between 1998-2004.

RESULTS

The mean age at birth was 32.1 for the genetic population and 29.6 for the source population (p = .000). In the genetic population, a higher use was found for antimigraine medication (RR = 2.7, 95% CI = 1.0-7.8) and for ovulation stimulants (RR = 1.6, 95% CI = 1.0-2.6). After adjustment for maternal age, the difference in use of ovulation stimulants disappeared.

CONCLUSIONS

Except for antimigraine medication, first trimester drug use among mothers of infants with genetic disorders is representative for the general pregnant population.

Therapeutic drug use in women with Crohn's disease and birth outcomes: a Danish nationwide cohort study

BACKGROUND

Crohn's disease (CD) is associated with increased risk of adverse birth outcomes. However, existing studies have not taken into account the impact of drug treatment. We examined the impact of drug treatment on birth outcomes--low birth weight (LBW), preterm birth, LBW at term, and congenital abnormalities (CAs)--among CD women.

METHODS

A nationwide Danish cohort study of 900 children born to CD women between 1996 and 2004, based on the National Registry of Patients, the Birth Registry, and the nationwide prescription database. Pregnancies were classified according to receipt of prescriptions for CD medication: no drugs (reference group), 5-aminosalicylic acid (5-ASA)/sulfasalazine, steroids, and azathioprine (AZA)/6-mercaptopurine (6-MP). We used logistic regression analyses to estimate the relative risk of birth outcomes with 95% confidence intervals. We used a proxy measure for disease activity.

RESULTS

Preterm births were more prevalent among steroid- and AZA/6-MP-exposed women (12.3% and 25%, respectively) compared with the reference group (6.5%). CAs were more prevalent among AZA/6-MP-exposed compared with reference group (15.4%vs 5.7%). Among steroid exposed, the risk of preterm birth was 1.4 (95% CI 0.6-3.3). Among AZA/6-MP exposed, the risk of preterm birth and CAs was 4.2 (95% CI 1.4-12.5) and 2.9 (95% CI 0.9-8.9), respectively.

CONCLUSIONS

The relative risk of adverse birth outcomes among CD women varied by type of drugs prescribed during pregnancy. The risk of preterm birth and CAs was greater when AZA/6-MP was prescribed, even after adjusting for confounders. However, further information is needed to determine whether the associations are causal.

A possible association between maternal glomerulonephritis and congenital intestinal atresia/stenosis--a population-based case-control study

The objective of the study was to estimate association between maternal glomerulonephritis during pregnancy and structural birth defects, i.e. congenital abnormalities. The prevalence of maternal glomerulonephritis during the first trimester of pregnancy in cases with different congenital abnormalities was compared to that of matched controls without congenital abnormalities in the population-based Hungarian Case-Control Surveillance System of Congenital Abnormalities. Of 22,843 cases with congenital abnormalities, 309 (1.35%) had mothers with glomerulonephritis during pregnancy, compared to 479 (1.26%) of 38,151 controls (adjusted POR with 95% CI = 1.0, 0.9-1.2). Specified groups of congenital abnormalities were also assessed versus controls. Cases with isolated intestinal atresia/stenosis (adjusted POR with 95% CI: 6.8, 1.3-37.4) based on five cases were more likely to have mothers with prospectively and medically recorded glomerulonephritis. In conclusion a higher rate of congenital isolated intestinal atresia/stenosis may be associated with the maternal glomerulonephritis. However, this finding is considered only as signal and further studies are needed to confirm or reject this possible association.

A population-based case-control study on the effect of bronchial asthma during pregnancy for congenital abnormalities of the offspring

Bronchial asthma is one of the most common maternal diseases complicating pregnancy. We assessed the risks of congenital abnormalities in a case-control population-based analysis using the dataset of the Hungarian Case-Control Surveillance of Congenital Abnormalities between 1980 and 1996. Of the 22,843 cases with congenital abnormalities, 511 (2.2%) had mothers with bronchial asthma, while of the 38,151 matched control subjects without congenital abnormalities 757 (2.0%) had mothers with bronchial asthma (unadjusted prevalence odds ratios [POR] 1.2; 95% CI: 1.0-1.3). In all mothers with bronchial asthma, a higher incidence of respiratory tract infections and higher drug intake could be observed. In the case group of medically recorded bronchial asthma, a slightly increased risk for club foot has been revealed. However, this weak association could be explained by the higher proportion of preterm births in this group. The main limitation of the analysis was that at the time of data collection only a small proportion of pregnant mothers were using anti-asthma medications recommended by the actual guidelines.

Drug treatment during pregnancy and isolated orofacial clefts in hungary

OBJECTIVE

To evaluate the possible association between all kinds of drug treatments during pregnancy and isolated cleft lip with or without cleft palate (CL/P) and posterior cleft palate (PCP) in the offspring.

SETTING

The dataset of the large population-based Hungarian Case-Control Surveillance of Congenital Abnormalities, 1980-1996, was evaluated.

PARTICIPANTS

One thousand three hundred seventy-four cases with isolated CL/P and 601 with PCP, plus 38,151 population controls (without birth defects) and 20,868 malformed controls with other defects.

INTERVENTION

In this observation case-control study the data collection was based on prospective medical records particularly prenatal logbook, retrospective maternal data via a self-reported questionnaire, and home visits of nonresponding mothers.

MAIN OUTCOME MEASURES

Isolated CL/P and PCP associated with drug treatments during pregnancy.

RESULTS

An increased risk for isolated CL/P was found in cases born to mothers treated with amoxicillin, phenytoin, oxprenolol, and thiethylperazine during the second and third month of pregnancy, i.e., the critical period of isolated CL/P. Risk of isolated PCP was increased in mothers with oxytetracycline and carbamazepine treatment during the third and fourth month of pregnancy, i.e., the critical period of PCP.

CONCLUSIONS

This study confirmed the orofacial cleft (OFC) inducing effect of phenytoin, carbamazepine, oxytetracycline, and thiethylperazine and suggested a possible association between OFCs and oxprenolol and amoxicillin. However, drugs may have only a limited role in the origin of isolated OFCs.