Investigating outcomes associated with medication use during pregnancy: A review of methodological challenges and observational study designs

The Methodological Quality of Observational Studies Examining the Risk of Pregnancy Drug Use on Congenital Malformations Needs Substantial Improvement: A Cross-Sectional Survey

BACKGROUND AND OBJECTIVE

An increasing number of observational studies have investigated the risk of using drugs during pregnancy on congenital malformations. However, the credibility of the causal relationships drawn from these studies remains uncertain. This study aims to evaluate the potential methodological issues in existing observational studies.

METHODS

We used a stepwise approach to investigate this issue. First, we identified observational studies published in 2020 that examined the risk of congenital malformations associated with medication use during pregnancy. We assessed the methodological characteristics for establishing causality, including study design, confounding control, and sensitivity analysis, and compared them between "core clinical journals" and "general journals." For studies reporting an increased risk of congenital malformations in core clinical journals, we searched for subsequent studies addressing the same research question published between January 2021 and May 2023 to assess the consistency of the literature.

RESULTS

A total of 40 eligible studies were published in 2020, primarily focused on the safety of vitamin B12 and folic acid (n = 4), antidepressants (n = 4), and others (n = 32). Our findings suggest that only two (5.00%) studies used causal models to guide the identification of confounding, and only eight (20.00%) studies assessed the potential dose-response relationship. In all, 15 (37.50%) studies used propensity score analysis strategy to achieve "mimic-randomization." In addition, 22 studies (55.00%) performed sensitivity analyses, while 10 (45.45%) showed inconsistency with the primary outcome. Furthermore, 5 studies reported positive outcomes, whereas only 1 out of 11 studies demonstrated a positive correlation between drug usage during pregnancy and major malformations in subsequent studies.

CONCLUSION

A significant portion of the studies has failed to sufficiently consider the essential methodological characteristics required to improve the credibility of causal inferences. The increased risk of congenital malformations documented in core clinical journal was not adequately replicated in subsequent studies.

A critical appraisal of controlled studies investigating malformation risks following pregabalin use in early pregnancy

In March 2022, the Summary of Product Characteristics for the Lyrica brand of pregabalin was updated with warnings regarding malformation risks. This literature review and critical appraisal aims to explore whether these Summary of Product Characteristics updates are justified and provide clarity on the risk-benefit balance for pregabalin use in early pregnancy. A literature review was conducted in May 2022 to identify English language comparative studies of any design providing data about first trimester maternal pregabalin use and malformation risk. Five observational comparative cohort studies using data from 9 distinct datasets were located. Collectively these studies described at least 5300 unique pregabalin exposed pregnancies, with 4900 exposed in at least the first trimester. Three studies investigated overall major malformation risks, and 4 investigated specific malformation risks. The available evidence was found to be conflicting and generally of low quality, probably influenced by bias and data confounding, with no clear pattern of specific malformations observed. Findings from the largest study suggested absolute risks of major malformation of 4.8-5.6%, relative to a background risk of approximately 4%. Due to study methodology limitations, the available data were judged to only provide low quality evidence suggestive of a possible and unconfirmed small increased risk that cannot be solely attributed to foetal pregabalin exposure. This literature review and critical appraisal indicates that the Lyrica product literature updates are insufficiently substantiated and could result in confusion and misinformed clinical risk-benefit decision making.

Development and Validation of Algorithms to Estimate Live Birth Gestational Age in Medicaid Analytic eXtract Data

BACKGROUND

While healthcare utilization data are useful for postmarketing surveillance of drug safety in pregnancy, the start of pregnancy and gestational age at birth are often incompletely recorded or missing. Our objective was to develop and validate a claims-based live birth gestational age algorithm.

METHODS

Using the Medicaid Analytic eXtract (MAX) linked to birth certificates in three states, we developed four candidate algorithms based on: preterm codes; preterm or postterm codes; timing of prenatal care; and prediction models - using conventional regression and machine-learning approaches with a broad range of prespecified and empirically selected predictors. We assessed algorithm performance based on mean squared error (MSE) and proportion of pregnancies with estimated gestational age within 1 and 2 weeks of the gold standard, defined as the clinical or obstetric estimate of gestation on the birth certificate. We validated the best-performing algorithms against medical records in a nationwide sample. We quantified misclassification of select drug exposure scenarios due to estimated gestational age as positive predictive value (PPV), sensitivity, and specificity.

RESULTS

Among 114,117 eligible pregnancies, the random forest model with all predictors emerged as the best performing algorithm: MSE 1.5; 84.8% within 1 week and 96.3% within 2 weeks, with similar performance in the nationwide validation cohort. For all exposure scenarios, PPVs were >93.8%, sensitivities >94.3%, and specificities >99.4%.

CONCLUSIONS

We developed a highly accurate algorithm for estimating gestational age among live births in the nationwide MAX data, further supporting the value of these data for drug safety surveillance in pregnancy. See video abstract at, http://links.lww.com/EDE/B989 .

Cohort profile: the Western Cape Pregnancy Exposure Registry (WCPER)

PURPOSE

The Western Cape Pregnancy Exposure Registry (PER) was established at two public sector healthcare sentinel sites in the Western Cape province, South Africa, to provide ongoing surveillance of drug exposures in pregnancy and associations with pregnancy outcomes.

PARTICIPANTS

Established in 2016, all women attending their first antenatal visit at primary care obstetric facilities were enrolled and followed to pregnancy outcome regardless of the site (ie, primary, secondary, tertiary facility). Routine operational obstetric and medical data are digitised from the clinical stationery at the healthcare facilities. Data collection has been integrated into existing services and information platforms and supports routine operations. The PER is situated within the Provincial Health Data Centre, an information exchange that harmonises and consolidates all health-related electronic data in the province. Data are contributed via linkage across a unique identifier. This relationship limits the missing data in the PER, allows validation and avoids misclassification in the population-level data set.

FINDINGS TO DATE

Approximately 5000 and 3500 pregnant women enter the data set annually at the urban and rural sites, respectively. As of August 2021, >30 000 pregnancies have been recorded and outcomes have been determined for 93%. Analysis of key obstetric and neonatal health indicators derived from the PER are consistent with the aggregate data in the District Health Information System.

FUTURE PLANS

This represents significant infrastructure, able to address clinical and epidemiological concerns in a low/middle-income setting.

Determining antenatal medicine exposures in South African women: a comparison of three methods of ascertainment

BACKGROUND

In the absence of clinical trials, data on the safety of medicine exposures in pregnancy are dependent on observational studies conducted after the agent has been licensed for use. This requires an accurate history of antenatal medicine use to determine potential risks. Medication use is commonly determined by self-report, clinician records, and electronic pharmacy data; different data sources may be more informative for different types of medication and resources may differ by setting. We compared three methods to determine antenatal medicine use (self-report, clinician records and electronic pharmacy dispensing records [EDR]) in women attending antenatal care at a primary care facility in Cape Town, South Africa in a setting with high HIV prevalence.

METHODS

Structured, interview-administered questionnaires recorded self-reported medicine use. Data were collected from clinician records and EDR on the same participants. We determined agreement between these data sources using Cohen's kappa and, lacking a gold standard, used Latent Class Analysis to estimate sensitivity, specificity and positive predictive value (PPV) for each data source.

RESULTS

Between 55% and 89% of 967 women had any medicine use documented depending on the data source (median number of medicines/participant = 5 [IQR 3-6]). Agreement between the datasets was poor regardless of class except for antiretroviral therapy (ART; kappa 0.6-0.71). Overall, agreement was better between the EDR and self-report than with either dataset and the clinician records. Sensitivity and PPV were higher for self-report and the EDR and were similar for the two. Self-report was the best source for over-the-counter, traditional and complementary medicines; clinician records for vaccines and supplements; and EDR for chronic medicines.

CONCLUSIONS

Medicine use in pregnancy was common and no single data source included all the medicines used. ART was the most consistently reported across all three datasets but otherwise agreement between them was poor and dependent on class. Using a single data collection method will under-estimate medicine use in pregnancy and the choice of data source should be guided by the class of the agents being investigated.

Misleading meta-analyses of observational studies may generate unjustified alarms: The case of medications for nausea and vomiting in pregnancy

OBJECTIVES

Because observational studies often use imperfect measurements, results are prone to misclassification errors. We used as a motivating example the possible teratogenic risks of antiemetic agents in pregnancy since a large observational study recently showed that first-trimester exposure to doxylamine-pyridoxine was associated with significantly increased risk of congenital malformations as a whole, as well as central nervous system defects, and previous observational studies did not show such associations. A meta-analysis on this issue was carried out with the aim to illustrate how differential exposure and outcome misclassifications may lead to uncertain conclusions.

METHODS

Medline, searched to October 2019 for full text papers in English. Summary Odds Ratios (ORs) with confidence intervals (CIs) were calculated using random-effect models. Probabilistic sensitivity analyses were performed for evaluating the extension of differential misclassification required to account for the exposure-outcome association.

RESULTS

Summary ORs were 1.02 (95 % CI, 0.92-1.15), 0.99 (0.82-1.19) and 1.25 (1.08-1.44) for overall congenital, cardiocirculatory, and central nervous system malformations respectively. By assuming exposure and outcome bias factor respectively of 0.95 (i.e., newborns with congenital defects had exposure specificity 5% lower than healthy newborns) and 1.12 (i.e., exposed newborns had outcome sensitivity 12 % higher than unexposed newborns), summary OR of central nervous system defects became 1.13 (95 % CI, 0.99-1.29) and 1.17 (95 % CI, 0.99-1.38).

CONCLUSION

Observational investigations and meta-analyses of observational studies need cautious interpretations. Their susceptibility to several, often sneaky, sources of bias should be carefully evaluated.

Modeling exposures of medications used episodically during pregnancy: Triptans as a motivating example

PURPOSE

To assess the validity of dispensed prescription to classify exposure to medications used episodically during pregnancy, and to explore individual trajectories of episodic medication use across pregnancy, using triptans for migraine as the motivating example.

METHODS

We compared self-reported triptan use during pregnancy in The Norwegian Mother, Father and Child Cohort Study (MoBa) to dispensed prescriptions in The Norwegian Prescription Database and calculated Cohen's kappa coefficient (κ), sensitivity, specificity and predictive values using MoBa as reference standard. We used group-based trajectory modeling to estimate exposure trajectories in MoBa according to probability of triptan use across pregnancy.

RESULTS

We identified 6051 pregnancies where mothers filled at least one triptan prescription or reported migraine or triptan use in the 6 months before or during pregnancy. Sensitivity of prescribed triptans during pregnancy was low (39.1%), but specificity was quite high (95.4%). Agreement between the two data sources was fair (κ 0.36). We identified three trajectory groups in MoBa including constant-high, decreasing-medium and decreasing-low probability of triptan use across pregnancy.

CONCLUSIONS

Using dispensed prescriptions rather than self-report to classify exposure to triptans during pregnancy is likely to result in substantial under-estimation of exposure. In this study, traditional definitions of ever-exposed vs never-exposed failed to capture variations in drug utilization during pregnancy.

Medication Use During Pregnancy in Mainland China: A Cross-Sectional Analysis of a National Health Insurance Database

Purpose

This study aims to illustrate the prevalence and patterns of medication use among pregnant women in mainland China.

Patients and methods

Hospital and drugstore service data for a nationally representative sample of basic medical insurance (BMI) beneficiaries in 2015 were obtained from the China Health Insurance Association (CHIRA) database. A total of 7946 women who had singleton deliveries in 2015, aged between 12 and 54, and whose records in the CHIRA database covered at least one trimester were included in this study. We conducted descriptive analyses of sample characteristics, medication use prevalence, and number and types of medications used.

Results

We found that 11.7% of women used at least one medication during the course of pregnancy (median number of medications used = 6.7). Medication use was more common among those who were older, residing in Eastern China, or employed. Most commonly used medication groups by the Anatomical Therapeutic Chemical Classification System were B (Blood and blood forming organs, 49.3%), A (Alimentary tract and metabolism, 48.1%), G (Genito urinary system and sex hormones, 38.1%) and J (Antiinfectives for systemic use, 31.6%). Intravenous solutions, vitamins and minerals, progestogens, and beta-lactam antibacterials were the most frequently used medications from each of these four ATC groups, respectively. Moreover, 7.1% used at least one medication contraindicated in pregnancy.

Conclusion

This study showed that around one in 10 women used medication during pregnancy in mainland China and found possible cases of inappropriate or unsafe medication use.

Medication Use and Pain Management in Pregnancy: A Critical Review

BACKGROUND

Pain during pregnancy is common, and its management is complex. Certain analgesics may increase the risk for adverse fetal and pregnancy outcomes, while poorly managed pain can result in adverse maternal outcomes such as depression and hypertension. Guidelines to assist clinicians in assessing risks and benefits of exposure to analgesics for the mother and unborn infant are lacking, necessitating evidence-based recommendations for managing pain in pregnancy.

METHODS

A comprehensive literature search was conducted to assess pregnancy safety data for pharmacological and nonpharmacological pain management methods. Relevant clinical trials and observational studies were identified using multiple medical databases, and included studies were evaluated for quality and possible biases.

RESULTS

Paracetamol and nonsteroidal anti-inflammatory drugs (NSAIDs) are appropriate for mild to moderate pain, but NSAIDs should be avoided in the third trimester due to established risks. Short courses of weaker opioids are generally safe in pregnancy, although neonatal abstinence syndrome must be monitored following third trimester exposure. Limited safety data for pregabalin and gabapentin indicate that these are unlikely to be major teratogens, and tricyclic antidepressants and serotonin-norepinephrine reuptake inhibitors have limited but overall reassuring safety data. Many of the included studies were limited by methodological issues.

CONCLUSIONS

Findings from this review can guide clinicians in their decision to prescribe analgesics for pregnant women. Treatment should be tailored to the lowest therapeutic dose and shortest possible duration, and management should involve a discussion of risks and benefits and monitoring for response. Further research is required to better understand the safety profile of various analgesics in pregnancy.

Use and validity of child neurodevelopment outcome measures in studies on prenatal exposure to psychotropic and analgesic medications - A systematic review

In recent years there has been increased attention to child neurodevelopment in studies on medication safety in pregnancy. Neurodevelopment is a multifactorial outcome that can be assessed by various assessors, using different measures. This has given rise to a debate on the validity of various measures of neurodevelopment. The aim of this review was twofold. Firstly we aimed to give an overview of studies on child neurodevelopment after prenatal exposure to central nervous system acting medications using psychotropics and analgesics as examples, giving special focus on the use and validity of outcome measures. Secondly, we aimed to give guidance on how to conduct and interpret medication safety studies with neurodevelopment outcomes. We conducted a systematic review in the MEDLINE, Embase, PsycINFO, Web of Science, Scopus, and Cochrane databases from inception to April 2019, including controlled studies on prenatal exposure to psychotropics or analgesics and child neurodevelopment, measured with standardised psychometric instruments or by diagnosis of neurodevelopmental disorder. The review management tool Covidence was used for data-extraction. Outcomes were grouped as motor skills, cognition, behaviour, emotionality, or "other". We identified 110 eligible papers (psychotropics, 82 papers, analgesics, 29 papers). A variety of neurodevelopmental outcome measures were used, including 27 different psychometric instruments administered by health care professionals, 15 different instruments completed by parents, and 13 different diagnostic categories. In 23 papers, no comments were made on the validity of the outcome measure. In conclusion, establishing neurodevelopmental safety includes assessing a wide variety of outcomes important for the child's daily functioning including motor skills, cognition, behaviour, and emotionality, with valid and reliable measures from infancy through to adolescence. Consensus is needed in the scientific community on how neurodevelopment should be assessed in medication safety in pregnancy studies. Review registration number: CRD42018086101 in the PROSPERO database.

Administrative Claims Data Versus Augmented Pregnancy Data for the Study of Pharmaceutical Treatments in Pregnancy

Purpose of Review

Administrative claims databases, which collect reimbursement-related information generated from healthcare encounters, are increasingly used to evaluate medication safety in pregnancy. We reviewed the strengths and limitations of claims-only databases and how other data sources may be used to improve the accuracy and completeness of information critical for studying medication safety in pregnancy.

Recent Findings

Research on medication safety in pregnancy requires information on pregnancy episodes, mother-infant linkage, medication exposure, gestational age, maternal and birth outcomes, confounding factors, and (in some studies) long-term follow-up data. Claims data reliably identifies live births and possibly other pregnancies. It allows mother-infant linkage and has prospectively collected prescription medication information. Its diagnosis and procedure information allows estimation of gestational age. It captures maternal medical conditions but generally has incomplete data on reproductive and lifestyle factors. It has information on certain, typically short-term maternal and infant outcomes that may require chart review confirmation. Other data sources including electronic health records and birth registries can augment claims data or be analyzed alone. Interviews, surveys, or biological samples provide additional information. Nationwide and regional birth and pregnancy registries, such as those in several European and North American countries, generally contain more complete information essential for pregnancy research compared to claims-only databases.

Summary

Claims data offers several advantages in medication safety in pregnancy research. Its limitations can be partially addressed by linking it with other data sources or supplementing with primary data collection. Rigorous assessment of data quality and completeness is recommended regardless of data sources.

Perception of drug teratogenicity among general practitioners and specialists in obstetrics/gynecology: a regional and national questionnaire-based survey

BACKGROUND

Estimating the true risk of fetal malformations attributable to the use of medications is difficult and perception of risk by health professionals will impact their counseling and treatment of patients who need medication during pregnancy. The objective of this study was to assess the perception of the teratogenic risk of 9 commonly and 3 rarely prescribed drugs among general practitioners and specialists in obstetrics/gynecology.

METHODS

All 811 general practitioners in the Region of Southern Denmark and all 502 specialist obstetricians/gynecologists in Denmark as a whole were invited to participate in the study based on an online questionnaire. Medians and interpercentile ranges of the perceived background risk and perceived risks for each of the drugs were included in the questionnaire.

RESULTS

One hundred forty three (18 %) general practitioners and 138 (27 %) obstetricians/gynecologists participated. Estimates provided by the participants were generally in accordance with current knowledge of drugs with established safety during pregnancy. Perceptions of risks associated with warfarin and retinoid exposure were severely underestimated.

CONCLUSIONS

Understanding of teratogenic background risk and specific risks associated with in utero exposure to 12 different drugs generally approached the established knowledge. The risk associated with warfarin and retinoid exposure was severely underestimated by both groups of health care professionals, while general practitioners specifically overestimated the risk of sertraline and citalopram to some extent. In Denmark, general practitioners can prescribe antidepressants, and even minor misconceptions of the teratogenic potential of citalopram and sertraline may be of clinical relevance. In Denmark, systemic retinoids can only be prescribed by a dermatologist, and warfarin treatment is only rarely initiated in women of the fertile age without involvement of specialists in internal medicine. Hence, the active knowledge on the teratogenic potential of these drugs is likely to be less accurate among general practitioners and obstetricians/gynecologists; although still of clinical importance since these specialists are largely involved in the counselling of pregnant women.

How to take into account exposure to drugs over time in pharmacoepidemiology studies of pregnant women?

PURPOSE

The aim of this study was to develop a new pharmacoepidemiological method to take into account intensity and evolution of drug exposure, applied to pregnant women.

METHODS

Pregnant women were classified according to their drug exposure, in three steps: Conversion of prescription data into exposure variables (using ATC-DDD) Construction of individual trajectories of exposure Clustering of individual trajectories of exposure (using the R package Kml) We applied this method to psychotropic drugs prescribed during pregnancy. The present study involved women, included in the EFEMERIS database, who gave birth in Haute-Garonne (France) between 2004 and 2010 (N = 54 918).

RESULTS

Exposure to psychotropic drugs of 3708 pregnant women was studied (6.7%). The pregnant women could be classified into four groups with homogeneous trajectories of exposure: low constant exposure during pregnancy (Cluster A: 70.8% of women); decreasing exposure during the first trimester of pregnancy and low constant exposure thereafter (Cluster B: 19.6%); moderate constant exposure (Cluster C: 8.2%); and high albeit decreasing exposure (Cluster D: 1.4%).

CONCLUSIONS

The proposed new method enabled us to describe more precisely women's exposure to drugs during pregnancy, and to distinguish different profiles of exposure. This method could be used to investigate specific outcomes related to duration and intensity of drug exposure during pregnancy, and also to study adverse drug reactions throughout life. Copyright © 2016 John Wiley & Sons, Ltd.

An International Study of the Ability and Cost-Effectiveness of Advertising Methods to Facilitate Study Participant Self-Enrolment Into a Pilot Pharmacovigilance Study During Early Pregnancy

Background

Knowledge of the fetal effects of maternal medication use in pregnancy is often inadequate and current pregnancy pharmacovigilance (PV) surveillance methods have important limitations. Patient self-reporting may be able to mitigate some of these limitations, providing an adequately sized study sample can be recruited.

Objective

To compare the ability and cost-effectiveness of several direct-to-participant advertising methods for the recruitment of pregnant participants into a study of self-reported gestational exposures and pregnancy outcomes.

Methods

The Pharmacoepidemiological Research on Outcomes of Therapeutics by a European Consortium (PROTECT) pregnancy study is a non-interventional, prospective pilot study of self-reported medication use and obstetric outcomes provided by a cohort of pregnant women that was conducted in Denmark, the Netherlands, Poland, and the United Kingdom. Direct-to-participant advertisements were provided via websites, emails, leaflets, television, and social media platforms.

Results

Over a 70-week recruitment period direct-to-participant advertisements engaged 43,234 individuals with the study website or telephone system; 4.78% (2065/43,234) of which were successfully enrolled and provided study data. Of these 90.4% (1867/2065) were recruited via paid advertising methods, 23.0% (475/2065) of whom were in the first trimester of pregnancy. The overall costs per active recruited participant were lowest for email (€23.24) and website (€24.41) advertisements and highest for leaflet (€83.14) and television (€100.89). Website adverts were substantially superior in their ability to recruit participants during their first trimester of pregnancy (317/668, 47.5%) in comparison with other advertising methods (P<.001). However, we identified international variations in both the cost-effectiveness of the various advertisement methods used and in their ability to recruit participants in early pregnancy.

Conclusions

Recruitment of a pregnant cohort using direct-to-participant advertisement methods is feasible, but the total costs incurred are not insubstantial. Future research is needed to identify advertising strategies capable of recruiting large numbers of demographically representative pregnant women, preferentially in early pregnancy.

Accuracy of information on medication use and adverse drug reactions recorded in pregnancy hand-held records

BACKGROUND

Pregnancy hand-held records (PHR) are a personally controlled health record utilised in the promotion of continuity of care across pregnancy by providing a single resource for the recording of pregnancy-related health information.

AIMS

To determine the accuracy of the PHR in relation to information on medications and adverse drug reactions (ADRs) and to examine the frequency and nature of any identified discrepancies.

MATERIALS AND METHODS

A 12-week prospective clinical audit of 300 women admitted to either the antenatal or postnatal ward at a tertiary-level maternity hospital. A detailed medication history was completed for each woman by a pharmacist, with women interviewed about medication use prior to and during their pregnancy as well as any ADRs. The medication history and PHR were compared to identify discrepancies.

RESULTS

Medication discrepancies were extremely common, with 254 (84.7%; 95% CI 80.6-88.8%) women having at least one or more medication-related discrepancy involving 686 (55%; 95% CI 52.2-57.8%) prescription and nonprescription medications. Most common reasons for prescription medication discrepancies included the medication details being incomplete (44%), missing (29%) or incorrect (17%). ADRs and allergy discrepancies were also common, identified among 59 (20%; 95% CI 15.5-24.5%) women.

CONCLUSIONS

The PHR is of low accuracy in relation to the recording of medications and ADRs. This warrants further research to examine the impact of these discrepancies on patient care and outcomes. The identification of strategies for improving the recording of information on medications and ADRs in the PHR is also required.

Influences on participant reporting in the World Health Organisation drugs exposure pregnancy registry; a qualitative study

Background

The World Health Organisation has designed a pregnancy registry to investigate the effect of maternal drug use on pregnancy outcomes in resource-limited settings. In this sentinel surveillance system, detailed health and drug use data are prospectively collected from the first antenatal clinic visit until delivery. Over and above other clinical records, the registry relies on accurate participant reports about the drugs they use. Qualitative methods were incorporated into a pilot registry study during 2010 and 2011 to examine barriers to women reporting these drugs and other exposures at antenatal clinics, and how they might be overcome.

Methods

Twenty-seven focus group discussions were conducted in Ghana, Kenya and Uganda with a total of 208 women either enrolled in the registry or from its source communities. A question guide was designed to uncover the types of exposure data under- or inaccurately reported at antenatal clinics, the underlying reasons, and how women prefer to be asked questions. Transcripts were analysed thematically.

Results

Women said it was important for them to report everything they had used during pregnancy. However, they expressed reservations about revealing their consumption of traditional, over-the-counter medicines and alcohol to antenatal staff because of anticipated negative reactions. Some enrolled participants' improved relationship with registry staff facilitated information sharing and the registry tools helped overcome problems with recall and naming of medicines. Decisions about where women sought care, which influenced medicines used and antenatal clinic attendance, were influenced by pressure within and outside of the formal healthcare system to conform to conflicting behaviours. Conversations also reflected women's responsibilities for producing a healthy baby.

Conclusions

Women in this study commonly take traditional medicines in pregnancy, and to a lesser extent over-the-counter medicines and alcohol. The World Health Organisation pregnancy registry shows potential to enhance their reporting of these substances at the antenatal clinic. However, more work is needed to find optimal techniques for eliciting accurate reports, especially where the detail of constituents may never be known. It will also be important to find ways of sustaining such drug exposure surveillance systems in busy antenatal clinics.

Drug use during early pregnancy: cross-sectional analysis from the Childbirth and Health Study in Primary Care in Iceland

OBJECTIVE

To analyse drug use in early pregnancy with special focus on socio-demographic factors associated with psychotropic and analgesic drug use.

DESIGN

Cross-sectional study.

SETTING AND SUBJECTS

A total of 1765 women were invited via their local health care centres, and 1111 participated at 11-16 weeks of pregnancy by filling out a postal questionnaire concerning socio-demographic and obstetric background, stressful life events, and drug use.

MAIN OUTCOME MEASURES

Drug use prior to and early on in pregnancy, socio-demographic factors, smoking, and adverse life events were investigated. Drug categories screened for were psychotropics (collective term for antidepressants, relaxants, and sleep medication), analgesics, hormones, nicotine, vitamins/minerals, and homeopathic medicine.

RESULTS

Drug use from the aforementioned drug categories, excluding vitamins/minerals and homeopathic medicine, was reduced by 18% during early pregnancy, compared with six months prior to conception (49% vs. 60%). Psychotropic drug use during early pregnancy was associated with elementary maternal education (p < 0.5), being unemployed (p < 0.001), being single/divorced/separated (p < 0.01), smoking prior to or during pregnancy (p < 0.01), forced to change job/move house (p < 0.001), and psychotropic drug use six months prior to pregnancy (p < 0.001). No items on the stressful life events scale were associated with increased analgesic use, which increased only with multiparity.

CONCLUSIONS

Use of analgesics and psychotropic drugs seems common in pregnancy. Our results indicate that lack of a support network, stressful life events, and lower status in society may predispose women to more drug use. GPs and midwives responsible for maternity care could take this into account when evaluating risk and gain for women and foetuses in the primary care setting.

Methodological challenges in using routinely collected health data to investigate long-term effects of medication use during pregnancy

To date, the investigation of teratogenic effects of medications has largely focused on physical alterations present at birth (i.e. malformations) as opposed to functional alterations (i.e. neurodevelopment, metabolic function) that may not be apparent at birth but could influence an individual's health and risk of disease in later life. The use of routinely collected health data represents one approach to better identifying, quantifying, and understanding the long-term risks or benefits of medication use during pregnancy. As such, the objective of this review was to identify and explore opportunities and challenges associated with using routinely collected health data to examine long-term effects of medication use during pregnancy. Drawing on published research several key methodological issues associated with their use in investigating long-term outcomes are reviewed. While significant opportunities exist to make greater use of routinely collected health data, there are a number of key challenges. Identified challenges relate to aspects of study design and analysis, and include obtaining access to data, the ability to match records across datasets and over long periods of time, how medication exposures are ascertained and classified, issues around loss to follow-up how outcomes are ascertained and classified, and the careful interpretation of results in light of study and data limitations. Understanding key challenges associated with using routinely collected health data to investigate long-term effects of medication use during pregnancy is essential in supporting their appropriate use and interpretation, which will contribute to improving the quality of research undertaken and ensure the reliability of results obtained.

Using multiple types of studies in systematic reviews of health care interventions--a systematic review

BACKGROUND

A systematic review may evaluate different aspects of a health care intervention. To accommodate the evaluation of various research questions, the inclusion of more than one study design may be necessary. One aim of this study is to find and describe articles on methodological issues concerning the incorporation of multiple types of study designs in systematic reviews on health care interventions. Another aim is to evaluate methods studies that have assessed whether reported effects differ by study types.

METHODS AND FINDINGS

We searched PubMed, the Cochrane Database of Systematic Reviews, and the Cochrane Methodology Register on 31 March 2012 and identified 42 articles that reported on the integration of single or multiple study designs in systematic reviews. We summarized the contents of the articles qualitatively and assessed theoretical and empirical evidence. We found that many examples of reviews incorporating multiple types of studies exist and that every study design can serve a specific purpose. The clinical questions of a systematic review determine the types of design that are necessary or sufficient to provide the best possible answers. In a second independent search, we identified 49 studies, 31 systematic reviews and 18 trials that compared the effect sizes between randomized and nonrandomized controlled trials, which were statistically different in 35%, and not different in 53%. Twelve percent of studies reported both, different and non-different effect sizes.

CONCLUSIONS

Different study designs addressing the same question yielded varying results, with differences in about half of all examples. The risk of presenting uncertain results without knowing for sure the direction and magnitude of the effect holds true for both nonrandomized and randomized controlled trials. The integration of multiple study designs in systematic reviews is required if patients should be informed on the many facets of patient relevant issues of health care interventions.