Do pregnant women report use of dispensed medications?

Prenatal antidepressant exposure and risk of spontaneous abortion - a population-based study

PURPOSE

To estimate the risk of spontaneous abortion after use of antidepressant medication during pregnancy.

METHODS

From the Danish Medical Birth Registry and the Danish National Hospital Registry, we identified all pregnancies leading to in- or outpatient contacts in Denmark from February 1997 to December 2008. The Danish Registry of Medicinal Product Statistics provided information on the women's prescriptions for antidepressants during pregnancy. We obtained information on women who were diagnosed with depression from the Danish Psychiatric Central Registry. Adjusted relative risks (aRR) of spontaneous abortion were estimated according to exposure to antidepressants or maternal depression using binomial regression.

RESULTS

Of the 1,005,319 pregnancies (547,300 women) identified, 114,721 (11.4%) ended in a spontaneous abortion. We identified 22,061 pregnancies exposed to antidepressants and 1,843 with a diagnosis of depression with no antidepressant use, of which 2,637 (12.0%) and 205 (11.1%) ended in a spontaneous abortion, respectively. Antidepressant exposure was associated with an aRR of 1.14 (95% confidence interval (CI) 1.10-1.18) for spontaneous abortion compared with no exposure to antidepressants. Among women with a diagnosis of depression, the aRR for spontaneous abortion after any antidepressant exposure was 1.00 (95% CI 0.80-1.24). No individual selective serotonin reuptake inhibitor (SSRI) was associated with spontaneous abortions. In unadjusted analyses, we found that mirtazapine, venlafaxine, and duloxetine were associated with spontaneous abortions among women with depression but we had no information on potential differences in disease severity and only few pregnancies were exposed in the population.

CONCLUSION

We identified a slightly increased risk of spontaneous abortion associated with the use of antidepressants during pregnancy. However, among women with a diagnosis of depression, antidepressants in general or individual SSRI in particular were not associated with spontaneous abortions. Further studies are warranted on the newer non-SSRI antidepressants, as we had insufficient data to adjust for important confounding factors.

Drug exposure: inclusion of dispensed drugs before pregnancy may lead to underestimation of risk associations

OBJECTIVES

To assess the impact of exposure misclassification on risk associations when using prescription databases as the source for drug exposure in pregnancy by applying results from a validation analysis of exposure classification.

STUDY DESIGN AND SETTING

Linkage of data on 27,656 participants in the Norwegian Mother and Child Cohort Study (MoBa) with the Norwegian Prescription Database (NorPD). Exposure to selective serotonin reuptake inhibitors (SSRIs) was defined by dispensed drugs during pregnancy including different time windows before pregnancy. The validity of NorPD data was estimated using self-reported use in MoBa as the reference standard. We applied the results from the validation analysis on data from a Nordic study on SSRI use in pregnancy and risk of persistent pulmonary hypertension in the newborn.

RESULTS

Sensitivity increased and specificity decreased when the time window in NorPD was expanded before pregnancy. Using the same time window as in the Nordic study (+90 days before pregnancy), for use in early pregnancy, the odds ratio (OR) corrected for misclassification was 2.6 compared with the OR of 1.6 in the Nordic study.

CONCLUSION

Expansion of the time window to include intervals before pregnancy can lead to lower specificity and underestimation of risk associations.

Prevalence of antidepressant use during pregnancy in Denmark, a nation-wide cohort study

AIM

The aim of this study was to assess the prevalence and patterns of exposure to antidepressants before, during and after pregnancy in a cohort including all pregnant women in Denmark between 1997 and 2010.

METHODS

We performed a retrospective cohort study including 912 322 pregnancies. Information was retrieved from the Danish Birth Registry and The Register of Medicinal Product Statistics to identify women redeeming an antidepressant prescription during pregnancy. Exposure periods were based on standard treatment doses and dispensed pack sizes.

RESULTS

We identified 19 740 pregnancies exposed to an antidepressant at some point during pregnancy. The rate of exposure increased from 0.2% in 1997 to 3.2% in 2010. We found that the rate of exposure was halved during the first 3 months of pregnancy. In contrast, we describe a clear increase in exposure after pregnancy among pre-delivery treatment-naïve women.

CONCLUSIONS

In spite of uncertainty concerning antidepressants' safety during pregnancy we find a 16-fold increase in exposure rates between 1997 and 2010. The rates describe a sharp decrease in exposure during pregnancy that is probably caused by physicians' hesitation to prescribe antidepressants and women's fear of unwanted effects on the unborn child. More studies are needed to clarify the consequences of antidepressant discontinuation during pregnancy.

Prenatal valproate exposure and risk of autism spectrum disorders and childhood autism

IMPORTANCE

Valproate is used for the treatment of epilepsy and other neuropsychological disorders and may be the only treatment option for women of childbearing potential. However, prenatal exposure to valproate may increase the risk of autism.

OBJECTIVE

To determine whether prenatal exposure to valproate is associated with an increased risk of autism in offspring.

DESIGN, SETTING, AND PARTICIPANTS

Population-based study of all children born alive in Denmark from 1996 to 2006. National registers were used to identify children exposed to valproate during pregnancy and diagnosed with autism spectrum disorders (childhood autism [autistic disorder], Asperger syndrome, atypical autism, and other or unspecified pervasive developmental disorders). We analyzed the risks associated with all autism spectrum disorders as well as childhood autism. Data were analyzed by Cox regression adjusting for potential confounders (maternal age at conception, paternal age at conception, parental psychiatric history, gestational age, birth weight, sex, congenital malformations, and parity). Children were followed up from birth until the day of autism spectrum disorder diagnosis, death, emigration, or December 31, 2010, whichever came first.

MAIN OUTCOMES AND MEASURES

Absolute risk (cumulative incidence) and the hazard ratio (HR) of autism spectrum disorder and childhood autism in children after exposure to valproate in pregnancy.

RESULTS

Of 655,615 children born from 1996 through 2006, 5437 were identified with autism spectrum disorder, including 2067 with childhood autism. The mean age of the children at end of follow-up was 8.84 years (range, 4-14; median, 8.85). The estimated absolute risk after 14 years of follow-up was 1.53% (95% CI, 1.47%-1.58%) for autism spectrum disorder and 0.48% (95% CI, 0.46%-0.51%) for childhood autism. Overall, the 508 children exposed to valproate had an absolute risk of 4.42% (95% CI, 2.59%-7.46%) for autism spectrum disorder (adjusted HR, 2.9 [95% CI, 1.7-4.9]) and an absolute risk of 2.50% (95% CI, 1.30%-4.81%) for childhood autism (adjusted HR, 5.2 [95% CI, 2.7-10.0]). When restricting the cohort to the 6584 children born to women with epilepsy, the absolute risk of autism spectrum disorder among 432 children exposed to valproate was 4.15% (95% CI, 2.20%-7.81%) (adjusted HR, 1.7 [95% CI, 0.9-3.2]), and the absolute risk of childhood autism was 2.95% (95% CI, 1.42%-6.11%) (adjusted HR, 2.9 [95% CI, 1.4-6.0]) vs 2.44% (95% CI, 1.88%-3.16%) for autism spectrum disorder and 1.02% (95% CI, 0.70%-1.49%) for childhood autism among 6152 children not exposed to valproate.

CONCLUSIONS AND RELEVANCE

Maternal use of valproate during pregnancy was associated with a significantly increased risk of autism spectrum disorder and childhood autism in the offspring, even after adjusting for maternal epilepsy. For women of childbearing potential who use antiepileptic medications, these findings must be balanced against the treatment benefits for women who require valproate for epilepsy control.

Medicines information needs during pregnancy: a multinational comparison

OBJECTIVES

The aim was to assess the perceived needs of medicines information and information sources for pregnant women in various countries.

DESIGN

Cross-sectional internet-based study.

SETTING

Multinational.

PARTICIPANTS

Pregnant women and women with children less than 25 weeks.

PRIMARY AND SECONDARY OUTCOME MEASURES

The need for information about medicines was assessed by a question: 'Did you need information about medicines during the course of your pregnancy?' A list of commonly used sources of information was given to explore those that are used.

RESULTS

Altogether, 7092 eligible women responded to the survey (5090 pregnant women and 2002 women with a child less than 25 weeks). Of the respondents, 57% (n=4054, range between different countries 46-77%) indicated a need for information about medicines during their pregnancy. On average, respondents used three different information sources. The most commonly used information sources were healthcare professionals-physicians (73%), pharmacy personnel (46%) and midwifes or nurses (33%)-and the internet (60%). There were distinct differences in the information needs and information sources used in different countries.

CONCLUSIONS

A large proportion of pregnant women have perceived information needs about medicines during pregnancy, and they rely on healthcare professionals. The internet is also a widely used information source. Further studies are needed to evaluate the use of the internet as a medicines information source by pregnant women.

Autism after infection, febrile episodes, and antibiotic use during pregnancy: an exploratory study

OBJECTIVES

Results of animal studies suggest that maternal immune activation during pregnancy causes deficiencies in fetal neurodevelopment. Infectious disease is the most common path to maternal immune activation during pregnancy. The goal of this study was to determine the occurrence of common infections, febrile episodes, and use of antibiotics reported by the mother during pregnancy and the risk for autism spectrum disorder (ASD) and infantile autism in the offspring.

METHODS

We used a population-based cohort consisting of 96 736 children aged 8 to 14 years and born from 1997 to 2003 in Denmark. Information on infection, febrile episodes, and use of antibiotics was self-reported through telephone interviews during pregnancy and early postpartum. Diagnoses of ASD and infantile autism were retrieved from the Danish Psychiatric Central Register; 976 children (1%) from the cohort were diagnosed with ASD.

RESULTS

Overall, we found little evidence that various types of mild common infectious diseases or febrile episodes during pregnancy were associated with ASD/infantile autism. However, our data suggest that maternal influenza infection was associated with a twofold increased risk of infantile autism, prolonged episodes of fever caused a threefold increased risk of infantile autism, and use of various antibiotics during pregnancy were potential risk factors for ASD/infantile autism.

CONCLUSIONS

Our results do not suggest that mild infections, febrile episodes, or use of antibiotics during pregnancy are strong risk factors for ASD/infantile autism. The results may be due to multiple testing; the few positive findings are potential chance findings.

Drug use before and during pregnancy in Serbia

BACKGROUND

Observation of drug use patterns during pregnancy is necessary for the recognition of potential bad practices and improvement of safe drug use in pregnancy.

OBJECTIVE

To investigate prescription and over the counter drug use among Serbian women in the 6 months before pregnancy and in the first 6 months of pregnancy, and to evaluate the drugs used according to the risk to a fetus. Setting Six maternity care units and five community pharmacies.

METHOD

A multi-center study was performed in Serbia during the period from March 2009-March 2010. A self-reporting questionnaire was used as a data source. Food and Drug Administration (FDA) risk classification system was used to determine the risk of used drugs for the fetus. Differences between subgroups were assessed using McNemar's test on paired proportions. Main outcome measure Proportion of women exposed to drugs or class of drugs.

RESULTS

The overall drug exposure was higher in pregnancy (34.7 %) than before pregnancy (29.9 %), p > 0.05, in the cohort of 311 pregnant women. A significantly greater prescription drug use, 19.0 versus 27.3 % of women, p < 0.05, and less selfmedication with over the counter drugs in pregnancy, 15.1 versus 8.7 %, p < 0.05, were observed. Commonly used drugs were musculoskeletal drugs, analgesics/antipyretics and respiratory system drugs before pregnancy (13.8, 12.5, and 6.4 % of women, respectively), and progestogens, analgesics/antipyretics, and antibiotics for the systemic use in pregnancy (9.0, 7.7, and 7.4 %, respectively). A greater exposure to drugs belonging to the FDA risk category A (3.9 vs. 60.8 %, p < 0.05), B (18.0 vs. 19.6 %, p > 0.05), C (10.0 vs. 10.3 %, p > 0.05) and D (2.9 vs. 10.9 %, p < 0.05), as well as less exposure to drugs belonging to category X (0.3 vs. 0 %, p > 0.05) were observed in pregnancy. Folic acid was used by 60.8 % of women in pregnancy, and by only 3.9 % before pregnancy.

CONCLUSION

Besides higher overall drug use in pregnancy than before pregnancy, particularly the use of progestogens, and, subsequently, D category drugs, less selfmedication with over the counter drugs was observed in pregnancy. Insufficient use of folic acid before pregnancy requires public health service activities.

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.

Exposure to selective serotonin reuptake inhibitors and the risk of congenital malformations: a nationwide cohort study

OBJECTIVES

To analyse the relation between selective serotonin reuptake inhibitor (SSRI) use and major congenital malformations, with focus on malformations of the heart.

DESIGN

Register-based retrospective nationwide cohort study, using the Danish Medical Birth Registry.

SETTING

Denmark.

PARTICIPANTS

Pregnant women in Denmark between 1997 and 2009 and their offspring.

PRIMARY OUTCOME MEASURES

For each SSRI, ORs for major congenital malformations were estimated using multivariable logistic regression models for women exposed to an SSRI during the first trimester and for women with paused exposure during pregnancy.

RESULTS

The authors identified 848 786 pregnancies; 4183 were exposed to an SSRI throughout the first trimester and 806 pregnancies paused exposure during pregnancy. Risks of congenital malformations of the heart were similar for pregnancies exposed to an SSRI throughout the first trimester, adjusted OR 2.01 (95% CI 1.60 to 2.53), and for pregnancies with paused SSRI treatment during pregnancy, adjusted OR 1.85 (95% CI 1.07 to 3.20), p value for difference: 0.94. The authors found similar increased risks of specific congenital malformations of the heart for the individual SSRIs. Furthermore, the authors found no association with dosage.

CONCLUSIONS

The apparent association between SSRI use and congenital malformations of the heart may be confounded by indications. The moderate absolute risk increase combined with uncertainty for causality still requires the risk versus benefit to be evaluated in each individual case.

β-Blocker treatment during pregnancy and adverse pregnancy outcomes: a nationwide population-based cohort study

OBJECTIVE

To investigate the association between exposure to β-blockers during pregnancy and the risk of being born small for gestational age (SGA), preterm birth and perinatal mortality in a nationwide cohort.

DESIGN

A population-based retrospective cohort study, using the Danish Fertility Database. The authors identified all pregnant women redeeming a prescription for β-blockers using the National Prescription Registry. Multivariate logistic regression models were used to assess the association between exposure and our outcomes.

SETTING

Register-based survey.

PARTICIPANTS

911'685 births between 1995 and 2008 obtained from the Danish Fertility Database.

OUTCOME MEASURES

Being born SGA was defined as having a birth weight below the 10th percentile for the corresponding gestational week. Preterm birth was defined as birth before the 37th gestational week. Perinatal mortality was defined as either death occurring within the first 28 days of life or stillbirth. Before 2004, fetal deaths were recorded as stillbirths if they occurred after 28 weeks of gestation, but since then stillbirth is recorded for deaths after 22 gestational weeks.

RESULTS

The authors identified 2459 pregnancies exposed to β-blockers. β-Blocker exposure during pregnancy was found to be associated with increased risk of SGA (adjusted OR 1.97, 95% CI 1.75 to 2.23), preterm birth (adjusted OR 2.26, 95% CI 2.03 to 2.52) and perinatal mortality (adjusted OR 1.89, 95% CI 1.25 to 2.84). Analyses were adjusted for socioeconomic and maternal variables. The authors found similar risk profiles for pregnancies exposed to labetalol and for pregnancies exposed to other β-blockers.

CONCLUSIONS

The authors found that exposure to β-blockers during pregnancy was associated with being born SGA, preterm birth and perinatal mortality. Our findings show that labetalol is not safer than other β-blockers during pregnancy.

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.

Adherence with drug therapy in pregnancy

Available information suggests that nonadherence with medication is a common problem in pregnant women. Not taking prescribed drugs may have potentially negative consequences as patients may not achieve their therapeutic goal. In addition to the many factors that may influence medication-taking behaviour in the general population, unique challenges are encountered in pregnant women as both maternal health and fetal well-being must be considered. On the one hand, pregnant women may be motivated to keep their underlying disease under control, while, on the other hand, fear and anxiety regarding the potential harmful effects of their medication on their unborn child may result in poor adherence with needed medication. Providing evidence-based information, ideally preconceptually, regarding the effects of their medication during pregnancy may be important in avoiding misperceptions that lead to nonadherence.

Nationwide register-based surveillance system on drugs and pregnancy in Finland 1996-2006

PURPOSE

The aim of this population-based nationwide drugs and pregnancy surveillance system was to get basic information on the use of prescribed drugs during pregnancy and to achieve more detailed information on drug exposure-outcome associations with data obtained from the Finnish national health registers.

METHODS

The data are based on information on all pregnancies ending in births (n = 632,629) or termination of pregnancy (TOP) (n = 117,255) in Finland between 1996 and 2006. The data containing information on maternal background factors, chronic diseases and drug purchases during pregnancy, born children, induced abortions, perinatal health and major congenital malformations were obtained from the Finnish national health registers. Information from the different registers was merged through record linkages based on unique personal identification numbers. Statistical analyses were conducted between the exposed and unexposed for individual drugs or Anatomical Therapeutic Chemical (ATC) classification drug groups in multivariate logistic regression including potential confounding factors.

RESULTS

Nearly half of parturients and almost every third woman with TOP purchased drugs at least once 1 month prior to pregnancy and/or during pregnancy. The most frequent chronic diseases during pregnancy were asthma, hypothyroidism, epilepsy, rheumatoid arthritis and diabetes. Previously known causal connections between maternal chronic diseases and/or medication and perinatal health risks were already seen in the ATC-group-level analysis.

CONCLUSIONS

Comprehensive and detailed information for pharmacoepidemiological research on the effects of drug use during pregnancy in a cohort setting is possible with long-term and cumulative data collection.

Maternal use of acetaminophen, ibuprofen, and acetylsalicylic acid during pregnancy and risk of cryptorchidism

BACKGROUND

Cyclooxygenase (COX) inhibitors-acetaminophen, ibuprofen and acetylsalicylic acid-have endocrine-disruptive properties in the rainbow trout. In humans, aspirin blocks the androgen response to human chorionic gonadotropin (hCG), and, because hCG-stimulated androgen production in utero is crucial for normal testicular descent, exposure to COX inhibitors at vulnerable times during gestation may impair testicular descent. We examined whether prenatal exposure to acetaminophen, ibuprofen, and acetylsalicylic acid was associated with increased occurrence of cryptorchidism.

METHODS

Our study used data on 47,400 live-born singleton sons of mothers enrolled in the Danish National Birth Cohort during 1996-2002. Cryptorchidism was identified in 980 boys during childhood, of whom 565 underwent orchiopexy. The use of acetaminophen, ibuprofen, and acetylsalicylic acid during pregnancy was assessed in 3 computer-assisted telephone interviews and 1 self-administered questionnaire. We estimated adjusted hazard ratios (HRs) of cryptorchidism by Cox regression analysis.

RESULTS

Exposure to acetaminophen during both the first and second trimesters was associated with increased occurrence of cryptorchidism (HR = 1.33 [95% confidence interval = 1.00-1.77]). Exposure for more than 4 weeks within the postulated time-window of programming testicular descent (gestational weeks 8-14) was associated with a HR of 1.38 (1.05-1.83) for cryptorchidism. Exposure to ibuprofen and acetylsalicylic acid was not associated with cryptorchidism.

CONCLUSION

Maternal intake of acetaminophen for more than 4 weeks during pregnancy, especially during the first and second trimesters, may moderately increase the occurrence of cryptorchidism.

Drug use during pregnancy in Sweden - assessed by the Prescribed Drug Register and the Medical Birth Register

Purpose:

The purpose of this research is to study drug use during pregnancy in Sweden and agreement between use according to antenatal medical records and dispensed drugs from a pharmacy database.

Patients and methods:

From the Swedish Medical Birth Register (MBR), we established a population-based cohort of 102,995 women who gave birth in 2007. Using the unique personal registration number, information on dispensed drugs from the Prescribed Drug Register (PDR) was obtained prior to, during, and after the pregnancies and compared with MBR information on drug use from standardized antenatal medical records.

Results:

According to the PDR, 57.6% of the 102,995 women filled a prescription with at least one drug during pregnancy and 50.9% during the lactating period (until 3 months after delivery). The most dispensed drugs during pregnancy were B-lactam antibacterials and penicillins. Agreement between drugs recorded in antenatal medical records and dispensed drugs was highest for drugs used for chronic conditions. The agreement was particularly high for thyroid therapy (85.3%), anti-intestinal inflammatory drugs (80.3%), antiepileptics (69.2%), immunosuppressants (67.4%), and insulin (63.8%). Agreement for drugs used for occasional use was generally lower, ranging between 42.5% for antihistamines and 0.8% for gynecological anti-infectives.

Conclusions:

A large proportion of women filled a prescription during pregnancy or the lactating period. Agreement between drug use in medical antenatal records and register information from a national pharmacy database was high for drugs used for chronic conditions but low for occasional use. For occasionally used drugs, medical record and register-based data may provide incomplete exposure information because of nonreporting or noncompliance.

Comparison of recorded medication use in the Medical Birth Registry of Norway with prescribed medicines registered in the Norwegian Prescription Database

PURPOSE

Maternal medication use during pregnancy is explored extensively, as it may cause birth defects. This study aimed to evaluate the validity of recorded medication use in the Medical Birth Registry of Norway (MBRN).

METHODS

This study was based on the nationwide population-based registries, the MBRN and the Norwegian Prescription Database (NorPD). These registries were linked using a unique 11-digit identification number. The sensitivity, specificity and positive predictive value (PPV) of recorded medication use in MBRN were computed using data from NorPD as the reference.

RESULTS

Among the 163,678 pregnancies included in our study, the sensitivity for total drug use during pregnancy was calculated to be 32% and PPV was 82%. When we looked at the use of medication during the whole pregnancy, the sensitivities of drug registration for the main groups in the Anatomical Therapeutic Chemical (ATC)-classification varied from 50% (ATC group H) to 2% (ATC group S).

CONCLUSION

The medication use recorded in MBRN is poor compared with prescribed medicines registered in NorPD. There was a substantial difference between the different ATC codes regarding the sensitivity of MBRN in the registration of medication use during pregnancy.

Oral antibiotic prescribing during pregnancy in primary care: UK population-based study

OBJECTIVES

To examine patterns of prescribing of oral antibiotics during pregnancy and to determine whether women were more or less likely to receive specific types of antibiotics in pregnancy than in the years before and after pregnancy. Finally, to identify socio-demographic factors associated with antibiotic prescribing in pregnancy.

PATIENTS AND METHODS

We identified 114 999 women who gave live birth between 1992 and 2007 in The Health Improvement Network (THIN) UK primary care database. Antibiotic prescribing during pregnancy was estimated for each calendar year between 1992 and 2007. Self-controlled case series (SCCS) methodology was used to compare antibiotic prescribing during pregnancy with the years before and after pregnancy, and Poisson regression to examine association between demographic factors and antibiotic prescribing.

RESULTS

A third of pregnant women received at least one antibiotic prescription during pregnancy. In each trimester, 14% of women received at least one antibiotic. Prescribing of antibiotics was lower in pregnancy than during a comparable period 1 year earlier [incidence rate ratio (IRR) 0.91 (95% CI 0.90-0.93)], but some antibiotics were prescribed more frequently in pregnancy: broad-spectrum penicillins [IRR 1.46 (1.42-1.49)]; cephalosporins [IRR 2.22 (2.13-2.31)]; and antibiotics for urinary tract infections [IRR 2.29 (2.01-2.61)]. Respiratory, urinary, skin and ear infections were the commonest indications. Urinary indications increased and respiratory, skin and ear infection indications declined during pregnancy, although a large proportion were prescribed without indication. Young age and social deprivation were associated with increased antibiotic prescribing during pregnancy.

CONCLUSIONS

Antibiotic prescribing is widespread in pregnancy although marginally reduced compared with the year before pregnancy. There were substantial changes in types of antibiotics as well as in their indications during pregnancy. This may be explained by changes in threshold for treatment, diseases, detection and recording. Younger women and women from deprived areas were most likely to receive antibiotics in pregnancy.

Medication use in early pregnancy-prevalence and determinants of use in a prospective cohort of women

PURPOSE

To examine the extent, nature and determinants of medication use in early pregnancy.

METHODS

We reviewed early pregnancy medication use, as reported to a midwife at the booking interview, in women delivering between 2000 and 2007 in a large maternity hospital in Dublin, Ireland (n = 61 252).

RESULTS

Excluding folic acid, at least one medication was reported in 23 989 (39.2%) pregnancies. Over the counter (OTC) medications were reported in 11 970 (19.5%) pregnancies, illicit drugs or methadone in 545 (0.9%) and herbal medicines/supplements in 352 (0.58%). FDA category D and X medications were reported by 1532 (2.5%) and 1987 (3.2%) women. Asthma, depression and hypertension were among the most commonly reported chronic medical disorders. Medications with potential for foetal harm were reported by 86 (15.7%) women treated for depression and 68 (20%) women treated for hypertension. Factors associated with reporting the use of medications with potential for foetal harm included unplanned pregnancy (adjusted odds ratio [aOR] 1.31, 95% confidence interval [CI] 1.12-1.52), booking at less than 12 weeks gestation (aOR 1.83, 95%CI 1.58-2.13), being above 25 years of age, unemployed (aOR 2.58, 95%CI 2.03-3.29), nulliparous (aOR 1.41; 95%CI 1.22-1.63), single (aOR 1.28; 95%CI 1.06-1.54) or smoking during pregnancy (aOR 1.96, 95%CI 1.67-2.28).

CONCLUSIONS

Women frequently report medication use in early pregnancy. Women and prescribers need to be aware of the lack of pregnancy safety data for many medications, and the need for pre-pregnancy planning. Prescribers should ensure that optimal medications are used when treating women of childbearing potential with chronic medical disorders.

Preparation, piloting and validation for a longitudinal birth cohort study

No longitudinal study should go into the field prior to detailed piloting and validation studies of the measures and techniques to be used. Preparation should also involve the training of staff, the acquisition of space and appropriate equipment, and liaison with the community and ethical committees as well as with scientific collaborators. Because different measures will continually be introduced as the participants age, the preparation, piloting and validation studies have to be ongoing. Here we describe some of the different strategies that should be used.

Nesting sub-studies and randomised controlled trials within birth cohort studies

Although birth cohort studies can stand on their own, there are a number of different types of sub-studies that can add value to the overall project. These can be summarised within four main categories: (A) more detailed observations of relatively small subgroups aimed at describing mechanisms and processes; (B) nested case-control studies; (C) use of detailed observations to validate data collection by questionnaire or interview; (D) randomised controlled trials. For each category we give examples of ways in which they have been employed in current pregnancy birth cohort studies.

Choice of environmental components for a longitudinal birth cohort study

Various aspects of the environment of the mother and child may have major influences on the health and development of the child. Long-term influences can even affect chronic diseases of adulthood. Here we describe the major psychosocial and physical environmental factors that should be measured in longitudinal birth cohort studies.

Data resources for investigating drug exposure during pregnancy and associated outcomes: the General Practice Research Database (GPRD) as an alternative to pregnancy registries

Pregnancy registries are the most commonly used data resource for the post-marketing surveillance of drug teratogenicity. However, the limited sample size and potential selection bias in these registries has led us to investigate the potential of the UK General Practice Research Database (GPRD) as an alternative data source for monitoring drug safety during pregnancy. In addition, a literature review identified further observational data sources that monitor pregnancy outcomes for future evaluation. Initial feasibility studies focused on the ability of the GPRD to capture pregnancy outcomes for a range of drug class exposures, all of which are currently under investigation in pregnancy registries, during pregnancy. The comparator pregnancy registries were identified via a MEDLINE search, whilst eligible pregnancies, in which women received one or more prescriptions for the drug of interest during pregnancy, were identified in the GPRD using the mother-baby link. The number of pregnancy outcomes following exposure to medication for a range of conditions with varying prevalence, including depression, migraine, epilepsy, herpes simplex and HIV, captured by the two data sources were compared. For depression, a relatively prevalent condition, the GPRD recorded the same number of mean annual intrauterine exposures to fluoxetine as the pregnancy registry (118 exposures/year). Ascertainment of intrauterine exposure to drug treatments for less prevalent conditions was found to be higher for the pregnancy registries than the GPRD; for the older antiepileptic drugs (valproate and carbamazepine), the pregnancy registry recorded between four and five times as many mean annual exposures as the GPRD. Virtually no antiretroviral exposures (three) were identified during the time period of interest on the GPRD, compared with 3946 in the Antiretroviral Pregnancy Registry. Data from the GPRD meet established criteria for evaluating outcomes of pregnancy. For prevalent conditions, it has the potential to replace or work alongside standard pregnancy registries and the alternative data sources identified. Further studies are now needed to assess its ability to replicate known teratogenic associations.

Using prescription registries to define continuous drug use: how to fill gaps between prescriptions

Pharmacoepidemiological studies often use prescription registries to assess patients' drug episodes. The databases usually provide information on the date of the redemption of the prescription as well as on the dispensed amount, and this allows us to define episodes of drug use. However, when patients take less medication than prescribed, apparent gaps between prescriptions occur, and most studies handle this issue by allowing for small gaps when defining continuous drug use. This paper argues that it becomes crucial whether gaps are 'filled' prospectively or retrospectively. In the latter case the inferred exposure status depends on the patient's future dispensing behaviour and this can lead to severe bias in the findings of the study. In this paper we investigate this potential bias in a study of the risk of acute myocardial infarction (AMI) for women using hormone therapy (HT), and we show that the retrospective exposure definition introduces an artificially protective effect of HT.

Prescribing of sulfasalazine, azathioprine and methotrexate round pregnancy--a descriptive study

PURPOSE

Continuation or discontinuation of drugs during pregnancy in chronic diseases is an issue of concern. Information on prescribing of disease modifying anti-rheumatic drugs (DMARDs) during pregnancy is scarce. In this study, we report prescribing patterns round pregnancy of sulfasalazine (SSZ), azathioprine (AZA), methotrexate (MTX) and co-medications among women to whom one of these DMARDs were prescribed before pregnancy.

METHODS

The pregnancy-interaction database (IADB.nl, 1994-2004), containing pharmacy dispensing data from Northern- Netherlands, was used. Women to whom SSZ (N = 13), AZA (N = 10) or MTX (N = 6) was prescribed before their first pregnancy were identified and described in detail.

RESULTS

AZA and SSZ are continued during pregnancy by 60% and 38% of the women, respectively, MTX was stopped before pregnancy. Among women receiving SSZ (N = 13) as their initial DMARD, anti-inflammatory and anti-rheumatic drugs (69%) and analgesics (45%) were the most commonly prescribed co-medications. Among women receiving AZA (N = 8) as their initial DMARD, corticosteroids for systemic use (100%) and intestinal anti-inflammatory agents (88%) were the most commonly prescribed co-medications. All women receiving intestinal anti-inflammatory drugs before pregnancy continued this during pregnancy, in contrast to other co-medications which were mainly discontinued.

CONCLUSIONS

Our study showed that DMARDs and co-medication are received before, during and after pregnancy, although no specific prescription patterns were found. Administrative databases, such as the pregnancy-IADB.nl, are useful in describing drug-prescribing patterns for better understanding of drug prescribing around pregnancy in daily practice. Based on these data, we conclude that prescribing of DMARDs and related co-medication is based on the individual patient.

Acetaminophen use during pregnancy: effects on risk for congenital abnormalities

OBJECTIVE

We evaluated if acetaminophen, one of the most frequently used drugs among pregnant women is associated with an increased prevalence of congenital abnormalities.

STUDY DESIGN

We selected 88,142 pregnant women and their liveborn singletons from the Danish National Birth Cohort who had information on acetaminophen use during the first trimester of pregnancy. We used the National Hospital Registry to identify 3784 (4.3%) children from the cohort diagnosed with 5847 congenital abnormalities.

RESULTS

Children exposed to acetaminophen during the first trimester of pregnancy (n = 26,424) did not have an increased prevalence of congenital abnormalities (hazard ratio = 1.01, 0.93-1.08) compared with nonexposed children (n = 61,718). No association was found between congenital abnormalities and duration of use during the first trimester. Increased prevalence was not observed for specific abnormalities, except for "medial cysts, fistula, sinus" (congenital abnormalities of the ear, face, and neck, ICD-10 code Q18.8, n = 43) with an adjusted hazard ratio of 2.15 (1.17-3.95).

CONCLUSION

Acetaminophen is not associated with an increased prevalence of congenital abnormalities overall or with any specific group of major abnormalities.

Are patients reliable when self-reporting medication use? Validation of structured drug interviews and home visits by drug analysis and prescription data in acutely hospitalized patients

The medication history among hospitalized patients often relies on patients' self-reports due to insufficient communication between health care professionals. The aim of the present study was to estimate the reliability of patients' self-reported medication use. Five hundred patients admitted to an acute medical department at a Danish university hospital were interviewed on the day of admission about their recent medication use. Blood samples drawn immediately after admission were screened for contents of 5 drugs (digoxin, bendroflumethiazide, amlodipine, simvastatin, glimepiride), and the results were compared to the patients' self-reported medication history. Information on prescribed drugs dispensed from any Danish pharmacy was collected from nationwide real-time pharmacy records. The authors performed home visits in a subgroup of 115 patients 4 weeks after their discharge. Stored drugs were inspected, and patients were interviewed about their drug use. Additional blood samples were drawn for drug analysis. The median age of included patients was 72 years, and 298 patients (60%) were women. Patients reported use of 3 (median) prescription-only medications (range, 0-14) during the structured interview. The congruence between self-report and drug analysis was high for all 5 drugs measured (all kappa >0.8). However, 9 patients (2%) reported use of drugs that were not detected in their blood samples. In 29 patients (6%), the blood samples contained drugs not reported during the structured interview, but 14 of these drugs were registered in either hospital files or pharmacy records. Overall, the sensitivity of information from hospital files, structured interviews, and pharmacy records in identifying drug users was 87% to 93%, with no significant differences between methods. In conclusion, patients' self-reports are reliable when estimating recent use of cardiovascular and antidiabetic drugs.

The use of nationwide on-line prescription records improves the drug history in hospitalized patients

WHAT IS ALREADY KNOWN ABOUT THIS SUBJECT

Structured medication interviews improve the medication history upon hospitalization. Pharmacy records are valid lists of the prescribed medications available to individual patients. In Denmark, treating doctors now have access to their patients' pharmacy records through a real-time online electronic database What this study adds: Omission errors are frequent among hospitalized patients despite structured drug interviews and home visits. Pharmacy records may be used to minimize patients' recall bias and improve the medication lists.

BACKGROUND

Structured medication interviews improve the medication history in hospitalized patients. In Denmark, a nationwide electronic version of individual pharmacy records (PR) has recently been introduced. Use of these records could improve the medication lists in hospitalized patients.

METHODS

We prospectively included 500 patients admitted to an acute medical department. In individual patients, the PR was compared with (i) the medication list written in the patient chart and (ii) drug information provided by the patient during a structured drug interview upon admission and during a home visit after discharge.

RESULTS

Median patient age was 72 years. Upon admission, patients reported using 1958 prescription-only medications (POM) (median four drugs per patient, range 0-14), of which 114 (6%) were not registered in PR. In PR, 1153 POM (median one per patient, range 0-11) were registered during the month preceding admission. The patients did not report 309 (27%) of these upon admission. Home visits were performed in a subgroup of 115 patients. During home visits, 18% of POM registered in PR during the preceding month were not reported. Drug type was predictive of reporting irrespective of patient sex or age. Cardiovascular drugs were reported most and dermatological were reported less frequently. Underreporting might be due to recall bias, non-adherence or discontinuation of drugs.

CONCLUSIONS

Omission errors are frequent despite structured medication interviews. Pharmacy records or medication lists from all treating doctors must be included in medication reviews in order to reduce recall bias.

Safety of leukotriene receptor antagonists in pregnancy

BACKGROUND

Asthma is a chronic disorder that affects about 8% of pregnant women and may complicate pregnancy. Adequate asthma therapy in pregnancy is crucial but challenging because of safety concerns for the fetus.

OBJECTIVE

To evaluate the safety of gestational asthma therapy with leukotriene receptor antagonists (LTRAs) for the mother and fetus/newborn.

METHODS

Subjects were participants of the Organization of Teratology Information Specialists Asthma Medications in Pregnancy Study. Perinatal outcomes among 96 women who took LTRAs (montelukast or zafirlukast) were compared with women who exclusively took short-acting beta(2)-agonists (n = 122) and women without asthma (n = 346).

RESULTS

Use of LTRAs was not associated with an increased risk of pregnancy loss, gestational diabetes, preeclampsia, low maternal weight gain, preterm delivery, low Apgar scores, or reduced measures of birth length and head circumference in infants (P > .05). Slightly decreased birth weight in infants born to LTRA users could be attributed to maternal asthma severity/control. The birth prevalence of major structural defects in the LTRA group (5.95%) was significantly higher compared with controls without asthma (P = .007), but not different from the comparison group with asthma (P = .524). Furthermore, the defects observed in the LTRA group did not represent a consistent pattern.

CONCLUSIONS

Use of LTRAs in pregnancy was not associated with a specific pattern of major structural anomalies in offspring or a large risk of other adverse perinatal outcomes.

CLINICAL IMPLICATIONS

This study suggests that LTRAs do not appear to be a major human teratogen; however, results should be interpreted with caution because of limited sample size.

Prescribing patterns of anti-emetic drugs during pregnancy in Germany

OBJECTIVES

The purpose of this study was to examine the prescribing patterns of anti-emetics for pregnant women in Germany.

METHOD

A large, nation-wide German statutory sickness fund provided data of reimbursed prescriptions and personal data for all insured women giving birth between June 2000 and May 2001 (n = 41,293). The prescribed drugs were classified according to the Anatomical Therapeutic Chemical code.

RESULT

About 13.9% (n = 5,746) of all pregnant women received an anti-emetic prescription. Over 98.5% of these women were treated with anti-emetics that are considered safe. But only 27.8% received the recommended anti-histamine meclozine and 2.1% the safest drug pyridoxine.

CONCLUSION

As there are no official guidelines for the treatment of nausea and vomiting during pregnancy in Germany, many different drugs are used, sometimes ignoring effectiveness and even safety. Therefore, evidence-based guidelines for anti-emetic therapy are needed.

Drug prescription patterns before, during and after pregnancy for chronic, occasional and pregnancy-related drugs in the Netherlands

OBJECTIVE

To compare the prescription of drugs in women over a period from 2 years before until 3 months after pregnancy, regarding the type of drugs used and the fetal risk.

DESIGN

A cohort study based on pharmacy records of women giving birth to a child between 1994 and 2003.

SETTING

The study was performed with data from the InterAction database, containing prescription-drug-dispensing data from community pharmacies.

POPULATION

The study population included 5412 women for whom complete pharmacy records were available.

METHODS

Drugs were classified into three categories: (1) drugs for chronic conditions, (2) drugs for occasional use and (3) drugs for pregnancy-related symptoms and also classified according to the Australian classification system.

MAIN OUTCOME MEASURES

The prescription rate was calculated as the number of women per 100 women who received one or more prescriptions for a given drug within a specified time period.

RESULTS

About 79.1% of the women received at least one prescription during pregnancy. The prescription rate for most drugs for chronic diseases and for occasional use decreased during pregnancy, whereas, as expected, the prescription rate for pregnancy-related drugs increased. During the first trimester of pregnancy, 1.7% of all drugs prescribed for chronic conditions and 2.3% of the occasional drugs were classified as harmful.

CONCLUSIONS

The increase in prescription rate during pregnancy is caused by an increase in prescription rate of drugs for pregnancy-related symptoms. The prescription of harmful drugs is more commonly associated with drugs for occasional use rather than with drugs for chronic conditions. Therefore, a more cautious prescribing of drugs to healthy women in the fertile age is necessary.

Associations between socio-economic factors and the use of prescription medication during pregnancy: a population-based study among 19,874 Danish women

OBJECTIVE

To examine the association between socio-economic factors and use of prescription medication during pregnancy in a population of Danish women.

METHODS

This was a population-based cohort study. Using record linkage from public administrative registries, we described the use of prescription medication during pregnancy and the financial and educational resources for each pregnant woman in the cohort.

RESULTS

The analyses included all 19,874 primiparous women delivering singletons in North Jutland county, Denmark, in 1991-1998. We identified 24,243 prescriptions filled by the women during their pregnancies. The highest overall prescription medication use was among women with basic schooling (OR 1.3; 95% CI 1.2-1.4), and lowest among women with the highest education (OR: 0.8; 95% CI 0.7-0.9) compared with women who had vocational education. Stratified analysis of therapeutic subgroups revealed that socio-economic factors were associated with the use of anti-infective and anti-asthmatic medications during pregnancy.

CONCLUSION

Maternal educational level, and to a lesser degree household income, paternal educational level and cohabitation status, was associated with the use of prescription medication during pregnancy. However, the analyses did not take into account important clinical variables such as maternal illness, and the results could be affected by differential misclassification of exposure information, by confounding or chance.

Antibiotics in pregnancy: analysis of potential risks and determinants in a large German statutory sickness fund population

PURPOSE

Antibiotics are frequently prescribed drugs in pregnancy. The purpose of the study was to analyse the use, the potential risks and the determinants of systemic antibiotic prescriptions during pregnancy.

METHODS

A large, nation-wide acting German statutory sickness fund provided prescription data and personal data of 41,293 pregnant women. For this study, all prescriptions of systemic antibiotics (ATC: J01) dispensed to each woman during a 21-month period were analysed. We used the FDA risk classification system and enrolled a literature search to identify potentially harmful antibiotics. To investigate the impact of geographical and socio-economic determinants in antibiotic prescribing, a multivariate logistic regression model was performed.

RESULTS

Of the 41,293 women, 19.7% received at least one antibiotic drug during pregnancy. There was a shift to relatively safe and reduced antibiotic drug use during pregnancy. Prescribing of contraindicated antibactericals or potentially harmful drugs was seen in 521 women (1.3% of all women). In the logistic regression, being younger than 21 years (adjusted OR 2.14, 95%CI 1.80-2.53) or being welfare recipient (adjusted OR 1.57, CI 1.25-2.00) was strongly associated with higher antibiotic use. Significantly lower antibiotic use was seen in 5 of 16 German federal states (OR 0.74-0.83).

CONCLUSIONS

About 20% of pregnant women received antibiotics, and 1.3% received a harmful drug. To minimise the risks, detailed guidelines are needed for the antibiotic treatment during pregnancy.

Developmental toxicity evaluation of ibuprofen and tolmetin administered in triple daily doses to Wistar CRL:(WI)WUBR rats

BACKGROUND

Ibuprofen and tolmetin are popular non-steroidal anti-inflammatory drugs. Previous animal studies taken with single daily doses showed their good prenatal tolerability. However, since both cyclooxygenase (COX) inhibitors have a short half-life, the current report presents drug developmental effects after triple daily doses administration, as they are used in human.

METHODS

Drugs were separately, orally dosed to pregnant rats triple daily 8 hr apart from day 8 to 21 (GD=1-plug day). The total daily doses were set at 25.5, 255.0, and 600.0 mg/kg for ibuprofen and 25.5, 255.0, and 2550.0 mg/kg for tolmetin. Fetuses were delivered on GD 21 and routinely examined. Comprehensive clinical and developmental measurements were done.

RESULTS

Maternal toxicity and intrauterine growth retardation were found in groups exposed to the highest doses of both drugs. An increase of external variations was reported in groups exposed to the middle and highest dose of ibuprofen and to the highest dose of tolmetin. Skeletal variations were significantly different only in litters treated with the highest doses of the drugs. Pooled statistical analysis showed a higher incidence of midline and ventricular septal (VSD) defect in rat fetuses exposed to COX inhibitors when compared with historical control data. For ibuprofen, the influence on VSD was similar to aspirin.

CONCLUSION

Both COX inhibitors were toxic to dams in the highest doses evaluated, which caused a significantly greater incidence of intrauterine growth retardation and developmental variations.

Medication use during pregnancy: data from the Avon Longitudinal Study of Parents and Children

OBJECTIVE

To present data on the self-reported use of all types of medicinal products collected during pregnancy in a large cohort in southwest England.

METHODS

Pregnant women with a delivery date during 1991-1992 and forming part of the prospective, population-based Avon Longitudinal Study of Parents and Children (ALSPAC) were sent up to four self-completion postal questionnaires during pregnancy. Text data collected from the questions on drug usage were coded using an ALSPAC drug dictionary based on the World Health Organization Drug Dictionary.

RESULTS

At least one antenatal self-completion questionnaire was completed for 14,119 pregnancies, and 11,545 women completed all four. The data included prescription, over-the-counter, herbal and homeopathic products as well as iron, vitamins and other supplements. Only 7.6% did not report use of any medicinal product throughout their entire pregnancy. The remaining 92.4% used at least one product at some stage. After exclusion of iron, folate, vitamins, supplements, herbal and homeopathic products and skin emollients, 83% of those completing all questionnaires had used conventional therapeutic drugs. Analgesics were reported by approximately one-third of women at each stage during pregnancy, and paracetamol was the most frequently reported substance. Iron preparations were reported by 33% of the full cohort, at some stage, and folate by 21.9%. Use of anti-anaemic products increased during pregnancy with the greatest incidence at 32 weeks. Other vitamins and supplements were taken by 17.4% at some stage. Use of vitamins decreased throughout pregnancy from 9.6% in early pregnancy to 5% at 32 weeks. Antacids were reported by 23% at 32 weeks. The reported incidence of antibiotic use decreased slightly during pregnancy from 8% early on to 5.8% at 32 weeks; amoxicillin was the most frequently reported antibacterial.

CONCLUSION

Use of medicinal products was high during pregnancy in the ALSPAC cohort. This finding is consistent with data from recent publications.

Prescription of Hazardous Drugs During Pregnancy

BACKGROUND

Prescribing drugs to pregnant women requires the balancing of benefits and risks. Only a small proportion of drugs are known to be harmful to the fetus, but for the vast majority of drugs little evidence of fetal safety exists.

AIM

To determine the prescription pattern of potentially and clearly harmful prescription drugs during pregnancy with reference to drug safety categorisation, and to define the drug groups primarily responsible for multiple drug use during pregnancy.

STUDY DESIGN

A retrospective, register-based cohort study.

METHODS

Linkage of three nationwide registers in Finland. Data collection included prescription drugs purchased during the preconception period and each trimester in the pregnant cohort, and the corresponding time periods in the non-pregnant controls. The pregnancy safety categorisation was determined for each drug (Anatomic Therapeutic Chemical [ATC] code) by using the Swedish classification of approved medicinal products (Farmaceutiska Specialiteter i Sverige [FASS]) and if not available, the corresponding Australian (Australian Drug Evaluation Committee [ADEC]) or US categorisation (FDA). GROUPS STUDIED: Women applying for maternity support (maternal grants) during the year 1999 (n = 43 470) plus non-pregnant control women matched by age and hospital district (n = 43 470).

RESULTS

In the pregnant cohort, 20.4% of women purchased at least one drug classified as potentially harmful during pregnancy, and 3.4% purchased at least one drug classified as clearly harmful. A significant decline occurred in the number of pregnant women purchasing potentially and clearly harmful drugs during the first trimester when compared with the preconception period, and the decline continued from the first to the second trimester. In the pregnant cohort, 107 (0.2%) women purchased at least ten different drugs during pregnancy. The drugs most commonly purchased in this group were topical corticosteroids and nasal preparations.

CONCLUSION

The use of hazardous prescription drugs declines during pregnancy but prescriptions of known teratogens and the relatively frequent practice of polypharmacy in epilepsy place emphasis on the need for careful pre-pregnancy counselling. However, drug safety classifications give a very crude estimation of risk and should only be used as general guidelines when planning treatment. Risk assessment must always be made on an individual basis, and pregnant women with illnesses requiring treatment must be treated adequately.

Prescription drugs during pregnancy and lactation--a Finnish register-based study

OBJECTIVE

To examine the use of prescription drugs in Finnish women before and during pregnancy and lactation.

METHODS

A register-based study linking four nation-wide registers in Finland: the Maternal Grants Register, the Drug Prescription Register, and the Special Refund Register (all maintained by the Social Insurance Institution in Finland; KELA), and the Finnish Population Register. The study included all women applying for maternity support (maternal grants) during the year 1999, and non-pregnant control women matched by age and hospital district. Data collection included the number and type of prescription drugs purchased by the two cohorts during preconception (3 months before pregnancy), each trimester, and lactation.

RESULTS

Of the 43,470 pregnant women, 46.2% purchased at least one drug and 12.7% three or more different drugs during pregnancy. Corresponding proportions for the control cohort were 55.2% (OR 0.7, 95% CI 0.6-0.7) and 23.0% (OR 0.5, 95% CI 0.5-0.5). The drugs most frequently purchased during pregnancy were systemic antibiotics (24.1% of pregnant women vs 27.3% controls; OR 0.8, 95% CI 0.8-0.9) and gynaecological anti-infective agents (8.3% vs 1.5%; OR 5.5, 95% CI 5.5-6.5). For pregnant women, purchases of most drug groups had already declined during the first trimester, but no reduction was apparent in drugs for chronic illnesses (epilepsy, asthma, diabetes).

CONCLUSIONS

Although drugs were purchased abundantly during pregnancy, a significant decline occurred for most drug groups. The medication pattern for chronic illnesses remained unchanged. The purchase of several different drugs was relatively common and raises concerns.

Pharmacy data in epidemiological studies: an easy to obtain and reliable tool

PURPOSE

The agreement between drug use measured in computerized pharmacy records and patient interviews or questionnaires is generally good. However, most investigations on this subject studied selected populations or subsets. We studied the coverage of Dutch pharmacy data for our study cohort, and the agreement between the different sources.

METHODS

We used the data from 8592 subjects of an on-going population-based study, focused on the impact of microalbuminuria (PREVEND). Data on drug use was collected in a questionnaire and at community pharmacies. Drug use was measured in the year preceding the questionnaire. Agreement between the sources was measured using kappa-values, sensitivity and positive predictive value.

RESULTS

Pharmacy data could be collected for 7568 (88%) of the study cohort. Pharmacy data and questionnaires showed good agreement for antihypertensives, lipid lowering drugs, oral antidiabetics and oral contraceptives, but poor agreement for nitrates, hormone replacement therapy and painkillers.

CONCLUSIONS

Pharmacy data could be collected for a large proportion of our cohort. For chronically used drugs pharmacy data generally agrees well with questionnaires. However, for drugs used for shorter periods, as needed, or also available over-the-counter, the agreement is not so good. Pharmacy data can be a valuable source of drug information in epidemiological studies.

A population-based study of maternal use of amoxicillin and pregnancy outcome in Denmark

AIMS

Amoxicillin is a widely used penicillin, but data on its safety in pregnancy are limited. We examined the association between amoxicillin exposure during pregnancy and birth weight, preterm delivery, congenital malformations, perinatal death, and spontaneous abortion.

METHODS

We identified all primiparous women with a live birth, or a stillbirth after the 28th gestational week, from 1 January 1991-31 December 2000 in the County of North Jutland, Denmark. Data on prescriptions for amoxicillin and outcome were obtained from population-based registries. Using a follow-up and a case-control design, we compared pregnancy outcomes between women who had been prescribed amoxicillin during pregnancy and those who had not, adjusting for available potentially confounding factors.

RESULTS

We identified 401 primiparous women who redeemed a prescription for amoxicillin during their pregnancy. The control group consisted of 10 237 primiparous women who did not redeem any prescriptions from 3 months before pregnancy until the end of pregnancy. The adjusted mean birth weight of children born to amoxicillin-exposed mothers was 57 g [95% confidence interval (CI) 9, 105] higher than that of children born to controls. Odds ratios among amoxicillin-exposed relative to controls were: low birth weight 0.63 (95% CI 0.26, 1.53), preterm delivery 0.77 (95% CI 0.49, 1.21), congenital malformation 1.16 (95% CI 0.54, 2.50), and spontaneous abortion 0.89 (95% CI 0.66, 1.18). We did not observe any cases of perinatal death in the amoxicillin-exposed women.

CONCLUSIONS

We did not find any increased risk of adverse pregnancy outcome associated with amoxicillin exposure during pregnancy, but additional studies are warranted.