Association of Commonly Prescribed Antepartum Medications and Incidence of Orofacial Clefting

BACKGROUND

Pharmacologic agents are often used in the antepartum period, however, studies on their effect on fetal development are limited. Thus, this study aims to examine the effect of commonly prescribed antepartum medications on the development of orofacial clefting.

METHODS

Utilizing EPIC Cosmos deidentified data from approximately 180 US institutions was queried. Patients born between January 1, 2013, to January 1, 2023, were included. Eight OC cohorts were identified. Gestational medication use was identified by medications prescribed, provider-administered, or reported use by mothers. Medications used in at least 1 in 10,000 pregnancies were included in this analysis.

RESULTS

A total of 12 098 newborns with available maternal pharmacologic data were born with any type of orofacial clefting. Prevalence for all oral clefts, any cleft palate, and any cleft lip were 20.56, 18.10, and 10.60 per 10 000 individuals, respectively. Notable significant exposures include most anticonvulsants, such as lamotrigine (OR1.33, CI 1.10-1.62), and topiramate (OR1.35, CI 1.13-1.62), as well as nearly all SSRIs/SNRIs, including fluoxetine (OR1.34, CI 1.19-1.51), sertraline (OR1.25, CI 1.16-1.34), and citalopram (OR1.28, CI 1.11-1.47). Corticosteroids were also correlated including dexamethasone (OR1.19, CI 1.12-1.27), and betamethasone (OR1.64, CI 1.55-1.73), as were antibiotics, including amoxicillin (OR1.22, CI 1.14-1.30), doxycycline (OR1.29, CI 1.10-1.52), and nitrofuran derivatives (OR1.10, CI 1.03-1.17).

CONCLUSION

New associations between commonly prescribed antepartum medications and orofacial clefting were found. These findings should be confirmed as causality is not assessed in this report. Practitioners should be aware of the potential increased risk associated with these medications.

Fetal and Neonatal Adverse Drug Reactions Associated with Biologics Taken During Pregnancy by Women with Autoimmune Diseases: Insights from an Analysis of the World Health Organization Pharmacovigilance Database (VigiBase®)

INTRODUCTION

Published data on the safety of biologics other than tumor necrosis factor (TNF) inhibitors during pregnancy are limited.

OBJECTIVE

The aim was to detect pharmacovigilance signals for fetal and neonatal adverse drug reactions (ADRs) to biologics taken by pregnant women with autoimmune diseases.

METHODS

We performed a disproportionality analysis of the World Health Organization's VigiBase^® pharmacovigilance database from 1968 to June 1, 2021. Data were collected in June 2021. By using terms for different hierarchical levels of the Medical Dictionary for Regulatory Activities, we selected the following fetal or neonatal ADRs: stillbirth, premature birth, low birth weight, small for gestational age, and congenital malformations. The frequency of all identified ADRs for biologics of interest (adalimumab, infliximab, golimumab, certolizumab, etanercept, anakinra, canakinumab, tocilizumab, sarilumab, ustekinumab, guselkumab, secukinumab, ixekizumab, belimumab, abatacept, and rituximab) was compared with that of all other reports for all other drugs and quoted as the reporting odds ratio (ROR) [95% confidence interval]. Reports with known concomitant use of teratogenic drugs were excluded from the main analysis. Other analyses included ROR stratifications by therapeutic indication in the periods 1968-2021 and 2001-2021, and an analysis after excluding reports with steroids.

RESULTS

In the main analysis, the RORs were particularly high for musculoskeletal malformations with anakinra (7.18 [3.50-14.73]), canakinumab (19.54 [12.82-29.79]), and abatacept (5.09 [2.77-9.33]), and for immune system disorders with canakinumab (347.88 [217.9-555.50]) and rituximab (9.27 [2.95-29.15]). After the exclusion of reports with steroids, the ROR was significant for neonatal infections with belimumab (28.49 [5.75-141.25]).

CONCLUSION

We identified possible associations with some adverse fetal and neonatal outcomes, suggesting that vigilance is required when prescribing certain biologics during pregnancy.

Knowledge, Attitudes, Beliefs, and Treatment Burden Related to the Use of Levothyroxine in Hypothyroid Pregnant Women in the United States

Background: The use of prescribed medications during pregnancy is a challenge and an underestimated source of treatment burden. Levothyroxine (LT4) for the treatment of overt and subclinical hypothyroidism is extensively prescribed during pregnancy. To this end, we aimed to explore the patients' perceived benefits and risks, knowledge, beliefs, attitudes, and related burden of LT4 therapy during pregnancy. Methods: In this cross-sectional study, we surveyed pregnant women who were treated with LT4 during pregnancy from January 1, 2019, to December 31, 2019, in a tertiary academic medical center of the United States. The anonymous online survey included questions to gather demographic data and multiple-choice questions regarding the benefits and risks, knowledge, beliefs, attitudes, and burden related to LT4 use during pregnancy. Results: Sixty-four pregnant women (mean age 31.5 years) completed the study survey (response rate: 96%): 62% were diagnosed with hypothyroidism more than 12 months before pregnancy, 16% less than or about 12 months before pregnancy, and 22% during pregnancy. We found that one-third of pregnant women using LT4 had a feeling of uneasiness/anxiety due to their hypothyroidism diagnosis. About half of the respondents (45%) reported that they did not receive an explanation by their clinician regarding the maternal/fetal risks of uncontrolled hypothyroidism or the benefits of adequate control. Finally, two in three patients expressed various concerns of LT4-related treatment burden. Conclusions: Our findings support the need for increased effective communication and tailored counseling to address fears, anxiety, and uncertainties about the benefits and risks of LT4 use in pregnancy. For patients with clear benefits from LT4 treatment in pregnancy, it could help to overcome their concerns, promote adherence, and decrease adverse maternal/fetal outcomes. For patients with no clear benefits established, clinicians need to be aware of LT4-related treatment burden in pregnancy and implement patient-centered approaches in their clinical practices.

Lifelong prevention of cardiovascular disease. Part I: preconceptional, prenatal and infant periods of life

Current prophylactic actions prevent or significantly delay the majority of cardiovascular diseases (CVD). Various factors are interconnected and affect a person throughout his life, determining the risk of CVD. This indicates the need for preventive measures at all stages of life and even before birth. The beneficial effects of CVD prevention are realized through various genetic, epigenetic and metabolic mechanisms. Due to the fact that many risk factors for CVD have a cumulative effect, the introduction of preventive measures from the earliest life stages will be most effective. The purpose of the article is to consider various aspects of CVD prevention in the preconceptional, prenatal and infant periods.

Maternal use of drugs and preeclampsia

AIMS

The aim was to compare and describe maternal use of drugs between women with preeclampsia and controls and to estimate the possible association with preeclampsia.

METHODS

The study cohort was collected from the Kuopio University Hospital Birth Register, which includes information about all women who gave birth in Kuopio University Hospital during the years 2002-2016, including information from approximately 36 000 parturients, of whom 1252 had preeclampsia. Maternal use of 16 groups of drugs during pregnancy was analysed from all women with preeclampsia and 1256 controls.

RESULTS

Every second woman had used at least 1 drug during pregnancy but those with preeclampsia had used significantly more than the controls (cases 59.5% vs controls 35.5%; p < 0.001). In both study groups, the most commonly used drugs were antibiotics (cases 19.5%, controls 17.0%), antihypertensives (cases 29.0%, controls 7.6%) and paracetamol (cases 13.1%, controls 5.9%). Women with preeclampsia had used significantly more benzodiazepines, paracetamol, antihypertensives and acid-suppressive drugs than the women in the control group (p < 0.05).

CONCLUSIONS

Women with preeclampsia were more likely to use medicines during pregnancy. While the association between benzodiazepines, antihypertensives and acid-suppressive drugs and preeclampsia may be explained by reverse causation, the association of paracetamol with preeclampsia remains to be clarified. Because paracetamol is a frequently used drug, more information about its safety during pregnancy including its role in preeclampsia is urgently needed.

Social media monitoring on the perceived safety of medication use during pregnancy: A case study from the Netherlands

Aims

An increasing number of women trust the Internet for information about medication safety during pregnancy. This study aimed to evaluate the availability and accuracy of social media content on the perceived safety of medication use in pregnancy.

Methods

We performed a systematic search of posts related to medication safety during pregnancy in the Dutch language published on social media, blogs and forums between May 2011 and April 2016 using Coosto, a tool for social media monitoring. The perceived safety in the posts was compared with the Dutch Teratology Information Service (TIS) safety classifications.

Results

We included 1224 online posts, which described 1441 scenarios about medication safety in pregnancy. A total of 820 (57%) scenarios were in line with the TIS classification. Incorrect perception was higher for prescription medication compared to medication available over‐the‐counter (60 vs 25%). Furthermore, the safety classification of medications with a TIS classification on strict indication or second‐line drugs (93%) and medications with insufficient knowledge on their safety during pregnancy (76%) was more likely to be incorrectly perceived by the public compared to medications with the TIS classification safe (24%).

Conclusions

Social media monitoring may be useful for surveillance of potentially unsafe use of medications in pregnancy. Many social posts related to medication safety during pregnancy provide inaccurate information. As this information may affect women's perceptions and decisions, accurate communication between healthcare providers and pregnant women regarding the benefits and risks of medications is vital.

Assessment of medication use during pregnancy by Web-based questionnaires, pharmacy records and serum screening

OBJECTIVE

To compare assessment of early pregnancy medication exposure using three methods of data collection.

METHODS

Serum samples were obtained from 752 women participating in the PRegnancy and Infant DEvelopment (PRIDE) Study before gestational week 17. For 52 women using medication at the date of blood sampling according to Web-based questionnaires or pharmacy records, we analysed serum samples using untargeted liquid chromatography time-of-flight spectrometry.

RESULTS

Medication was detected in 18 serum samples (35%). Medications taken orally for chronic conditions reported in the questionnaire were detected in serum and vice versa. Pharmacy records did not identify additional exposed women, but missed exposure in 5 women mainly due to unavailability. We observed substantial discordance between the three methods for inhaled medication, dermatological preparations, and medications for short-term use, which went often undetected in serum.

CONCLUSIONS

It remains challenging to assess medication use in large-scale studies as no 'gold standard' is currently available.

Descriptive epidemiology of cerebellar hypoplasia in the National Birth Defects Prevention Study

BACKGROUND

Cerebellar hypoplasia is a rare disorder of cerebellar formation in which the cerebellum is not completely developed, smaller than it should be, or completely absent. The prevalence of cerebellar hypoplasia at birth is unknown, and little is known about epidemiological risk factors. Using data from the National Birth Defects Prevention Study (NBDPS), a population-based, case-control study, we analyzed clinical features and potential risk factors for nonsyndromic cerebellar hypoplasia.

METHODS

The NBDPS included pregnancies with estimated delivery dates from 1997-2011. We described clinical features of cerebellar hypoplasia cases from the study area. We explored risk factors for cerebellar hypoplasia (case characteristics, demographics, pregnancy characteristics, maternal health conditions, maternal medication use, and maternal behavioral exposures) by comparing cases to non-malformed live born control infants. We calculated crude odds ratios (ORs) and 95% confidence intervals using logistic regression models.

RESULTS

We identified 87 eligible cerebellar hypoplasia cases and 55 mothers who participated in the NBDPS. There were no differences in clinical features between interviewed and non-interviewed cases. Cerebellar hypoplasia cases were more likely than controls to be from a multiple pregnancy, be born preterm, and have low birth weight. Cerebellar hypoplasia cases were more likely to be born in or after 2005, as opposed to earlier in NBDPS. We found elevated ORs that were not statistically significant for maternal use of vasoactive medications, non-Hispanic black mothers, and mothers with a history of hypertension.

CONCLUSIONS

Although unadjusted, our findings from a large, population-based study can contribute to new hypotheses regarding the etiology of cerebellar hypoplasia.

Trends in prescription drug use during pregnancy and postpartum in Norway, 2005 to 2015

PURPOSE

To explore trends in use of maternal medication 3 months prior to, during and 3 months after pregnancy.

METHODS

Data on births from the Medical Birth Registry of Norway were linked to the Norwegian Prescription Database, identifying women's use of medications around pregnancy. All women giving birth in Norway during 2005 to 2015 (638 532 singleton births to 414 567 women) were included. Proportions of pregnant women using different medications in association with pregnancy, and annual relative change in medication use during 2005 to 2015, were calculated.

RESULTS

In Norway, 60% of pregnant women used prescription medications during pregnancy (2005-15), increasing from 57% in 2005 to 62% in 2015. The annual relative increase was 0.9% (95% CI: 0.8-1.0). In the first trimester, approximately 17% of the women used medications regarded as potentially teratogenic during 2005 to 2015, increasing from 15% to 19%. Overall, this proportion was higher in the first than in the second (8.9%) and third (8.0%) trimesters, and higher than in the 3 months after pregnancy (14%). The annual relative increase of medications regarded as potentially teratogenic in the first trimester was 2.5% (95% CI: 2.3-2.7).

CONCLUSIONS

The proportion of women using potentially teratogenic medications in the first trimester of pregnancy have increased during the last decade. Clinicians need to be aware of the possibility of pregnancy when prescribing potentially teratogenic medication to women of fertile age and focus this in the consultations. The increasing trends call for the need of routine surveillance of adverse birth outcomes linked to medication use in pregnancy.

Pregnancy in Wilson's disease: Management and outcome

Wilson's disease (WD) is a rare inherited disorder of copper metabolism causing toxic hepatic and neural copper accumulation. Clinical symptoms vary widely, from asymptomatic disease to acute liver failure or chronic liver disease with or without neuropsychiatric symptoms. Continuation of specific medical treatment for WD is recommended during pregnancy, but reports of pregnancy outcomes in WD patients are sparse. In a retrospective, multicenter study, 282 pregnancies in 136 WD patients were reviewed. Age at disease onset, age at conception, and WD-specific treatments were recorded. Maternal complications during pregnancy, rate of spontaneous abortions, and birth defects were analyzed with respect to medical treatment during pregnancy. Worsening of liver function tests was evident during 16 of 282 (6%) pregnancies and occurred in undiagnosed patients as well as in those under medical treatment. Liver test abnormalities resolved in all cases after delivery. Aggravation of neurological symptoms during pregnancy was rare (1%), but tended to persist after delivery. The overall spontaneous abortion rate in the study cohort was 73 of 282 (26%). Patients with an established diagnosis of WD receiving medical treatment experienced significantly fewer spontaneous abortions than patients with undiagnosed WD (odds ratio, 2.853 [95% confidence interval, 1.634-4.982]). Birth defects occurred in 7 of 209 (3%) live births.

CONCLUSION

Pregnancy in WD patients on anticopper therapy is safe. The spontaneous abortion rate in treated patients was lower than that in therapy-naïve patients. Although the teratogenic potential of copper chelators is a concern, the rate of birth defects in our cohort was low. Treatment for WD should be maintained during pregnancy, and patients should be monitored closely for hepatic and neurological symptoms. (Hepatology 2018;67:1261-1269).

Prescription drug use during pregnancy in France: a study from the national health insurance permanent sample

PURPOSE

To provide an up-to-date account of drug prescription during pregnancy in France from 2011 to 2014 using the permanent sample of the French national computerized healthcare database and with a focus on recommended supplementations, fetotoxic drugs and teratogenic drugs.

METHODS

All pregnancies identified by the International Classification of Diseases, 10th Revision codes list in the hospitalization database, lasting more than 9 weeks of amenorrhea and whose delivery occurred between 01/01/2011 and 12/31/2014, were included. Drugs delivered between the trimester before and until the end of the pregnancy were included. Drug exposure prevalence was calculated for each year and according to pregnancy trimesters.

RESULTS

The study included 28,491 pregnancies with a median number of 9 [5-13] (median [IQ range]) drugs delivered. The most prescribed drug class was antianemia (in 72.5% of exposed). The prescription rate of recommended vitamins (B9 and D) increased over the study period (+10%). Influenza vaccination also increased but remained at a low rate (1%). Exposure to fetotoxic drugs decreased as pregnancy advanced. Exposure to the main teratogenic antiepileptics was stable over the study period. Low-income pregnant women had a higher average drug consumption except for recommended vitamins.

CONCLUSION

Pregnant French women are among the largest consumers of prescription medications worldwide. Overall, the dispensation trends observed in this study are in line with the recommendations of the French National College of Gynecologists and Obstetricians. Nevertheless, while being low, exposure to fetotoxic drugs, teratogenic drugs or those under safety alerts still occurred. Supplementations and vaccines in low-income pregnant women should also be increased.

Intra-laboratory validated human cell-based in vitro vasculogenesis/angiogenesis test with serum-free medium

Vasculogenesis and angiogenesis are the processes by which new blood vessels are formed. We have developed a serum-free human adipose stromal cell and umbilical cord vein endothelial cell based vasculogenesis/angiogenesis test. In this study, the test was validated in our GLP laboratory following the OECD Guidance Document 34 [1] using erlotinib, acetylic salicylic acid, levamisole, 2-methoxyestradiol, anti-VEGF, methimazole, and D-mannitol to show its reproducibility, repeatability, and predictivity for humans. The results were obtained from immunostained tubule structures and cytotoxicity assessment. The performance of the test was evaluated using 26 suspected teratogens and non-teratogens. The positive predictive value was 71.4% and the negative predictive value was 50.0%, indicating that inhibition of vasculogenesis is a significant mechanism behind teratogenesis. In conclusion, this test has great potential to be a screening test for prioritization purposes of chemicals and to be a test in a battery to predict developmental hazards in a regulatory context.

Human teratogens and genetic phenocopies. Understanding pathogenesis through human genes mutation

Exposure to teratogenic drugs during pregnancy is associated with a wide range of embryo-fetal anomalies and sometimes results in recurrent and recognizable patterns of malformations; however, the comprehension of the mechanisms underlying the pathogenesis of drug-induced birth defects is difficult, since teratogenesis is a multifactorial process which is always the result of a complex interaction between several environmental factors and the genetic background of both the mother and the fetus. Animal models have been extensively used to assess the teratogenic potential of pharmacological agents and to study their teratogenic mechanisms; however, a still open issue concerns how the information gained through animal models can be translated to humans. Instead, significant information can be obtained by the identification and analysis of human genetic syndromes characterized by clinical features overlapping with those observed in drug-induced embryopathies. Until now, genetic phenocopies have been reported for the embryopathies/fetopathies associated with prenatal exposure to warfarin, leflunomide, mycophenolate mofetil, fluconazole, thalidomide and ACE inhibitors. In most cases, genetic phenocopies are caused by mutations in genes encoding for the main targets of teratogens or for proteins belonging to the same molecular pathways. The aim of this paper is to review the proposed teratogenic mechanisms of these drugs, by the analysis of human monogenic disorders and their molecular pathogenesis.

Guideline for collection, analysis and presentation of safety data in clinical trials of vaccines in pregnant women

Vaccination during pregnancy is increasingly being used as an effective approach for protecting both young infants and their mothers from serious infections. Drawing conclusions from published studies in this area can be difficult because of the inability to compare vaccine trial results across different studies and settings due to the heterogeneity in the definitions of terms used to assess the safety of vaccines in pregnancy and the data collected in such studies. The guidelines proposed in this document have been developed to harmonize safety data collection in all phases of clinical trials of vaccines in pregnant women and apply to data from the mother, fetus and infant. Guidelines on the prioritization of the data to be collected is also provided to allow applicability in various geographic, cultural and resource settings, including high, middle and low-income countries.

EUROmediCAT signal detection: a systematic method for identifying potential teratogenic medication

AIMS

Information about medication safety in pregnancy is inadequate. We aimed to develop a signal detection methodology to routinely identify unusual associations between medications and congenital anomalies using data collected by 15 European congenital anomaly registries.

METHODS

EUROmediCAT database data for 14 950 malformed foetuses/babies with first trimester medication exposures in 1995-2011 were analyzed. The odds of a specific medication exposure (coded according to chemical substance or subgroup) for a specific anomaly were compared with the odds of that exposure for all other anomalies for 40 385 medication anomaly combinations in the data. Simes multiple testing procedure with a 50% false discovery rate (FDR) identified associations least likely to be due to chance and those associations with more than two cases with the exposure and the anomaly were selected for further investigation. The methodology was evaluated by considering the detection of well-known teratogens.

RESULTS

The most common exposures were genitourinary system medications and sex hormones (35.2%), nervous system medications (28.0%) and anti-infectives for systemic use (25.7%). Fifty-two specific medication anomaly associations were identified. After discarding 10 overlapping and three protective associations, 39 associations were selected for further investigation. These associations included 16 which concerned well established teratogens, valproic acid (2) and maternal diabetes represented by use of insulin (14).

CONCLUSIONS

Medication exposure data in the EUROmediCAT central database can be analyzed systematically to determine a manageable set of associations for validation and then testing in independent datasets. Detection of teratogens depends on frequency of exposure, level of risk and teratogenic specificity.

Congenital anomalies and in utero antiretroviral exposure in human immunodeficiency virus-exposed uninfected infants

IMPORTANCE

Most studies examining the association of prenatal antiretroviral (ARV) exposures with congenital anomalies (CAs) in children born to human immunodeficiency virus (HIV)-infected women have been reassuring, but some evidence suggests an increased risk with specific ARV agents.

OBJECTIVE

To evaluate the association of in utero ARV exposures with CAs in HIV-exposed uninfected children.

DESIGN, SETTING, AND PARTICIPANTS

Prospective cohort study design. The Pediatric HIV/AIDS Cohort Study's Surveillance Monitoring of ART Toxicities (SMARTT) Study was performed at 22 US medical centers among 2580 HIV-exposed uninfected children enrolled in the SMARTT Study between March 23, 2007, and June 18, 2012.

EXPOSURES

First-trimester exposure to any ARV and to specific ARV medications.

MAIN OUTCOMES AND MEASURES

The primary end point was a CA based on physician review of infant physical examinations according to the Antiretroviral Pregnancy Registry modification of the Metropolitan Atlanta Congenital Defects Program. Rates of CAs were estimated overall and by birth year. Logistic regression models were used to evaluate the association of CAs with first-trimester ARV exposures, adjusting for demographic and maternal characteristics.

RESULTS

Congenital anomalies occurred in 175 of 2580 children, yielding a prevalence of 6.78% (95% CI, 5.85%-7.82%); 242 major CAs were confirmed, including 72 musculoskeletal and 55 cardiovascular CAs. The prevalence of CAs increased significantly among successive birth cohorts (3.8% for children born before 2002 and up to 8.3% for those born 2008-2010). In adjusted models, no association of first-trimester exposures with CAs was found for any ARV, for combination ARV regimens, or for any drug class. No individual ARV in the reverse transcriptase inhibitor drug classes was associated with an increased risk of CAs. Among protease inhibitors, higher odds of CAs were observed for atazanavir sulfate (adjusted odds ratio [aOR], 1.95; 95% CI, 1.24-3.05) and for ritonavir used as a booster (aOR, 1.56; 95% CI, 1.11-2.20). With first-trimester atazanavir exposure, risks were highest for skin (aOR, 5.23) and musculoskeletal (aOR, 2.55) CAs.

CONCLUSIONS AND RELEVANCE

Few individual ARVs and no drug classes were associated with an increased risk of CAs in HIV-exposed infants after adjustment for calendar year and maternal characteristics. While the overall risk remained low, a relative increase was observed in successive years and with atazanavir exposure. Given the low absolute CA risk, the benefits of recommended ARV therapy use during pregnancy still outweigh such risks, although further studies are warranted.

Drugs associated with teratogenic mechanisms. Part I: dispensing rates among pregnant women in the Netherlands, 1998-2009

STUDY QUESTION

What are the dispensing rates of drugs suspected to be associated with teratogenic mechanisms among pregnant Dutch women?

SUMMARY ANSWER

In a substantial proportion of pregnancies in our study population at least one drug associated with a teratogenic mechanism was dispensed in the first trimester of pregnancy.

WHAT IS KNOWN ALREADY

The main teratogenic mechanisms of medical drugs that may affect fetal development in the first trimester of pregnancy have been described previously. However, information on the dispensing rate of such drugs among women at all stages of pregnancy is lacking.

STUDY DESIGN, SIZE, DURATION

To determine how often medications suspected to be associated with a teratogenic mechanism are used by pregnant women, we studied 32 016 pregnancies included in the IADB.nl database between 1998 and 2009.

PARTICIPANTS/MATERIALS, SETTING, METHODS

We estimated dispensing rates of medical drugs suspected to be associated with teratogenic mechanisms in our study population. The IADB.nl database includes all pharmacy dispensings for an estimated population of 220 000 in 1994-1998 and c.500 000 since 1999. In addition, trends in first trimester dispensing rates over time and patterns of receiving multiple drugs associated with teratogenic mechanisms were evaluated. In addition, we determined the number of pregnancies in which multiple prescription drugs from one or more teratogenic categories were dispensed in the first trimester, and we evaluated the numbers of different medications dispensed that could be grouped within a specific teratogenic mechanism.

MAIN RESULTS AND THE ROLE OF CHANCE

In 175 per 1000 pregnancies [95% confidence interval (CI), 171-179] at least one drug associated with a teratogenic mechanism was dispensed in the first trimester. The total dispensing rate was 236 per 1000 pregnancies (95% CI 232-241) in the 3 months before pregnancy and an increasing trend was seen in the second [214 per 1000 (95% CI 209-218)] and third [327 per 1000 (95% CI 322-332)] trimesters. The first trimester dispensing rates increased between 1998 and 2009 for selective serotonin-reuptake inhibitors (P < 0.001) and serotonin receptor agonists/antagonists (P < 0.001). In 71.8% of pregnancies in which drugs associated with teratogenic mechanisms were dispensed in the first trimester, women received drugs related to only one mechanism. Of the pregnancies in which drugs from multiple teratogenic categories were dispensed in the first trimester, 1148 (72.6%) women received drugs from 2 categories, 317 (20.0%) from three categories, 88 (5.6%) from 4 categories, 28 (1.8%) from 5 categories and 1 from 6 categories. Several women received multiple prescription medications grouped within a single teratogenic mechanism in the first trimester, ranging between 13.3% for cyclo-oxygenase inhibitors and 41.8% for serotonin receptor agonists/antagonists.

LIMITATIONS, REASONS FOR CAUTION

We used a dispensing database, therefore actual use of the medication prescribed is unknown and non-compliance could have led to overestimation of exposure prevalences.

WIDER IMPLICATIONS OF THE FINDINGS

Owing to the uncertainties concerning the safety of medication use during pregnancy, the results of this study stress the need for cautious prescription of medication associated with teratogenic mechanisms to women of reproductive age. This is further supported by our finding that women received multiple prescription medications grouped within a single teratogenic mechanism in the first trimester, which would theoretically increase strongly the risk of birth defects.

STUDY FUNDING/COMPETING INTEREST(S)

Marleen van Gelder was supported by the Netherlands Organisation for Scientific Research/NWO (grant no. 021.001.008). No competing interests are declared.

TRIAL REGISTRATION NUMBER

N/A.