Intrauterine exposure to mild analgesics during pregnancy and the occurrence of cryptorchidism and hypospadia in the offspring: the Generation R Study

Maternal intake of paracetamol during pregnancy and biomarkers of male fecundity in young adult sons

Paracetamol is suggested to have endocrine disrupting properties possibly affecting fetal programming of reproductive health that might lead to impaired semen quality and changes in reproductive hormones. In this longitudinal study, we included 1058 young adult men born 1998-2000 into the Danish National Birth Cohort with follow-up at 18-21 years of age. The exposure, maternal intake of paracetamol, was modelled in three ways: dichotomized, trimester-specific, and as duration of exposure categorized into: short (1-2 weeks), medium (3-9 weeks) or long duration (>9 weeks) vs. no intake. Outcomes included semen characteristics, self-measured testis volume, and reproductive hormone levels. We used negative binominal regression to estimate the percentage difference and 95% confidence interval (CI) for each outcome. In total, 547 (48%) sons were prenatally exposed to paracetamol due to maternal intake at least once. Maternal intake of paracetamol during pregnancy was not associated with any of the biomarkers in the dichotomized or trimester-specific exposure models. For duration of exposure, sons of mothers with long duration of maternal intake of paracetamol showed tendencies towards lower semen concentration (-14% [95% CI: -31%; 8%]), a higher proportion of nonprogressive and immotile spermatozoa (8% [95% CI: -4%; 21%]) and higher DNA Fragmentation Index (16% [95% CI: -1%; 36%]) compared to son of mothers with no intake. Maternal intake of paracetamol during pregnancy was not clearly associated with biomarkers of male fecundity in adult sons. However, it cannot be ruled out that long duration of maternal intake of paracetamol might be associated with impaired semen characteristics.

Safety of drugs used for the treatment of migraine during pregnancy: a narrative review

INTRODUCTION

Migraine is common in females of childbearing age and negatively impacts quality of life. The majority of those with migraine who become pregnant see an improvement in their condition but not all do. Providing evidence-based recommendations for the pharmacological management of migraine in pregnancy is challenging.

AREAS COVERED

This narrative review provides an update on the safety of drugs used for migraine in pregnancy. National and international guidelines on the management of episodic migraine in adults were used to select the drugs of relevance to pregnant women. The final list of drugs was chosen by a pain specialist who categorized them according to drug class and use in acute management or prevention. PubMed was searched from inception to 31st July 2022 for evidence on drug safety.

EXPERT OPINION

Obtaining high-quality drug safety data in pregnant migraineurs is difficult not least because exposing a fetus to research-related risks is often considered unethical. There is reliance on observational studies which often group drugs together and lack specificities pertinent to drug prescribing like timing, dosing and duration. Improved statistical tools, study designs and the creation of international collaborative frameworks are ways to advance knowledge on drug safety in pregnancy.

Urinary paracetamol (4-acetaminophenol) and its isomer 2-acetaminophenol of Chinese pregnant women: Exposure characteristics and association with oxidative stress biomarkers

N-Acetyl-4-aminophenol (NA4AP, paracetamol/acetaminophen), a widely used pharmaceutical, is ubiquitous in urine samples of general population, raising concern about human health risks; oxidative stress is considered to be a mechanism for its toxicities. N-Acetyl-2-aminophenol (NA2AP) is an isomer of NA4AP; until now, few studies characterized exposure characteristics of NA4AP and NA2AP in pregnant women. In this work, NA4AP and NA2AP concentrations in urine samples (n = 2124) collected at three different trimesters were measured to examine their internal body burden among Chinese pregnant women (n = 708) and their associations with three oxidative stress biomarkers (OSBs, 8-OHG, 8-OHdG, and HNE-MA). NA4AP was detected in 100% of the urine samples (median concentration: 7.96 ng/mL); NA2AP was detected in 94.9% of them (median: 3.05 ng/mL). The intraclass correlation coefficients of their concentrations across three trimesters were poor (<0.4); correlations of NA4AP and NA2AP were weak (r: 0.15-0.23). Pregnant women who had higher household income or urine samples provided in summer (vs. winter) had higher concentrations of NA4AP. Pregnant women who had a college degree or above (vs. less than a high school education) had higher concentrations of NA2AP but urine samples provided in summer (vs. winter) had lower concentrations of NA2AP. The 95th percentile estimated daily intake of NA4AP (2,331 ng/kg-bw/d) based on averaged concentrations of the three trimesters was 40 times lower than the cRfD for NA4AP (2.33 vs. 93 μg/kg-bw/d). Urinary concentrations of NA4AP and NA2AP were associated with higher levels of the selected OSBs. For example, an interquartile range increase in NA4AP was associated with a 26.5% (95% CI: 23.6-29.6%) increase in 8-OHG, a 27.5% (95% CI: 23.8-31.3%) increase in 8-OHdG, and a 33.4% (95% CI: 24.7-42.7%) increase in HNE-MA (p < 0.05). This is the first study to measure their concentrations repeatedly over three trimesters, examine their exposure characteristics, and reveal their associations with the selected OSBs in pregnant women. Further studies are needed to identify non-intentional exposure sources of NA4AP, NA2AP, and another isomer of them (i.e., N-acetyl-3-aminophenol), as well as more health risks related to their exposure.

Associations of maternal urinary bisphenol and phthalate concentrations with offspring reproductive development

Fetal exposure to bisphenols and phthalates may influence development of the reproductive system. In a population-based, prospective cohort study of 1059 mother-child pairs, we examined the associations of maternal gestational urinary bisphenols and phthalates concentrations with offspring reproductive development from infancy until 13 years. We measured urinary bisphenol and phthalate concentrations in each trimester. We obtained information on cryptorchidism or hypospadias after birth from medical records. At 9.7 years, we measured testicular and ovarian volume by MRI. At 13.5 years, we measured child Tanner stages and menstruation through questionnaire. We performed linear or logistic regression models for boys and girls to assess the associations of maternal urinary average and trimester-specific bisphenols and phthalates with child reproductive outcomes. Next, to further explore potential synergistic or additive effects of exposures together, we performed mixed exposure models using a quantile g computation approach. Models were adjusted for maternal age, ethnicity, body-mass index, education, parity, energy intake, smoking and alcohol use, and child's gestational age at birth, birthweight and body-mass index. In boys, no associations of maternal gestational phthalate or bisphenol with offspring cryptorchidism and hypospadias were found. Higher maternal high-molecular-weight phthalate and total bisphenol, but not phthalic acid or low-molecular-weight phthalate, were associated with larger child testicular volume at 10 years. Higher maternal phthalic acid and total bisphenol were associated with earlier genital and pubic hair development at 13 years, respectively (p-values<0.05). In girls, we found no associations of maternal urinary bisphenol and phthalate with ovarian volume or menstrual age. Only higher maternal urinary high-molecular-weight phthalate was associated with earlier pubic hair development at 13 years (p-values <0.05). Higher mixture exposure was associated with earlier pubic hair development in both sexes. In conclusion, higher maternal gestational urinary bisphenol and phthalate concentrations were associated with alterations in offspring reproductive development, mainly in boys.

The use of paracetamol during pregnancy: A qualitative study and possible strategies for a clinical trial

Paracetamol (N-acetyl-p-aminophenol (APAP), also known as acetaminophen) is used to relieve mild to moderate pain and reduce fever. APAP is widely used during pregnancy as it is considered safe when used as directed by regulatory authorities. However, a significant amount of epidemiological and experimental research suggests that prenatal exposure potentially alters fetal development. In this paper, we summarize the potentially harmful adverse effects of APAP and the limitations of the current evidence. It highlights the urgent need for a clinical trial, and the aim of the presented qualitative pilot study on APAP use during pregnancy is the feasibility of a large-scale randomized controlled trial (RCT). In the qualitative study, we included 232 Danish women from three hospitals in the spring of 2021. After recognizing the pregnancy, 48% had taken any APAP, and 6% had taken it weekly or more than weekly. A total of 27% who had taken APAP in the first trimester of pregnancy (even rarely) would potentially participate in an RCT. In a potential clinical trial, the women would need to be included early in the 1st trimester as the suspected harmful effects of APAP lies within this early reproductive developmental window. A possible recruitment strategy was explored. These data suggest that the target population appears positive towards an RCT. As a negative attitude among users has been considered the major hindrance for such a study, we cannot see hindrances for performing an RCT.

The Main Changes in Pregnancy—Therapeutic Approach to Musculoskeletal Pain

Background and Objectives: During pregnancy, women undergo various physiological and anatomical changes that are accentuated as the pregnancy progresses, but return to their previous state a few weeks/months after the pregnancy. However, a targeted therapeutic approach is needed. Most of the time, during this period, these changes precipitate the appearance of pain, musculoskeletal pain being the most common. Pregnant women should avoid treating musculoskeletal pain with medication and should choose alternative and complementary methods. Exercise along with rest is the basis for treating chronic musculoskeletal pain. Side effects of physical therapy are rare and, in addition, it is not contraindicated in pregnant women. The benefits of this type of treatment in combating pain far outweigh the risks, being an easy way to improve quality of life. The objective of this article is to discuss the management of musculoskeletal pain during pregnancy, to identify the main musculoskeletal pain encountered in pregnant women along with drug treatment, and to expose the beneficial effects of alternative and complementary methods in combating pain. Materials and Methods: A literature search was conducted using medical databases, including PubMed, Google Scholar, and ScienceDirect, using the keywords “changes of pregnancy”, “musculoskeletal pain”, “pregnancy pain”, “pain management”, “pharmacological approach”, “alternative and complementary treatment” and specific sites. Information was collected from studies whose target population included pregnant women who complained of musculoskeletal pain during the 9 months of pregnancy; pregnant women with other pathologies that could increase their pain were not included in this review. Results: The articles related to the most common non-obstetric musculoskeletal pain in pregnancy along with pharmacological treatment options and alternative and complementary methods for musculoskeletal pain management during pregnancy were selected. Conclusions: The results were used to guide information towards the safest methods of therapy but also to raise awareness of the treatment criteria in order to compare the effectiveness of existing methods. Treatment must consider the implications for the mother and fetus, optimizing non-pharmacological therapeutic options.

Maternal over-the-counter analgesics use during pregnancy and adverse perinatal outcomes: cohort study of 151 141 singleton pregnancies

OBJECTIVES

To identify any associations between in utero exposure to five over-the-counter (non-prescription) analgesics (paracetamol, ibuprofen, aspirin, diclofenac, naproxen) and adverse neonatal outcomes.

DESIGN

Retrospective cohort study using the Aberdeen Maternity and Neonatal Databank.

PARTICIPANTS

151 141 singleton pregnancies between 1985 and 2015.

MAIN OUTCOME MEASURES

Premature delivery (<37 weeks), stillbirth, neonatal death, birth weight, standardised birthweight score, neonatal unit admission, APGAR score at 1 and 5 min, neural tube and amniotic band defects, gastroschisis and, in males, cryptorchidism and hypospadias.

RESULTS

83.7% of women taking over-the-counter analgesics reported first trimester use when specifically asked about use at their first antenatal clinic visit. Pregnancies exposed to at least one of the five analgesics were significantly independently associated with increased risks for premature delivery <37 weeks (adjusted OR (aOR)=1.50, 95% CI 1.43 to 1.58), stillbirth (aOR=1.33, 95% CI 1.15 to 1.54), neonatal death (aOR=1.56, 95% CI 1.27 to 1.93), birth weight <2500 g (aOR=1.28, 95% CI 1.20 to 1.37), birth weight >4000 g (aOR=1.09, 95% CI 1.05 to 1.13), admission to neonatal unit (aOR=1.57, 95% CI 1.51 to 1.64), APGAR score <7 at 1 min (aOR=1.18, 95% CI 1.13 to 1.23) and 5 min (aOR=1.48, 95% CI 1.35 to 1.62), neural tube defects (aOR=1.64, 95% CI 1.08 to 2.47) and hypospadias (aOR=1.27, 95% CI 1.05 to 1.54 males only). The overall prevalence of over-the-counter analgesics use during pregnancy was 29.1%, however it rapidly increased over the 30-year study period, to include over 60% of women in the last 7 years of the study. This makes our findings highly relevant to the wider pregnant population.

CONCLUSIONS

Over-the-counter (non-prescription) analgesics consumption during pregnancy was associated with a substantially higher risk for adverse perinatal health outcomes in the offspring. The use of paracetamol in combination with other non-steroidal anti-inflammatory drugs conferred the highest risk. The increased risks of adverse neonatal outcomes associated with non-prescribed, over-the-counter, analgesics use during pregnancy indicate that healthcare guidance for pregnant women regarding analgesic use need urgent updating.

Maternal Paracetamol Intake During Pregnancy-Impacts on Offspring Reproductive Development

Paracetamol (acetaminophen) is the preferred antipyretic/analgesic for pregnant women as it is believed there are no adverse fetal effects at the recommended dose. However, emerging evidence suggests that intrauterine paracetamol exposure may be associated with certain urogenital/reproductive disorders in the offspring. In this mini-review, we describe human fetal sex development and possible pharmacological mechanisms by which paracetamol may disrupt this process, including reduced testicular production of testosterone and/or insulin-like peptide 3. We then review the available epidemiological literature on associations between maternal paracetamol exposure and offspring sexual development. Three epidemiological studies have reported associations between maternal paracetamol intake and increased risk of cryptorchidism, although five others have not. None have found associations with hypospadias or penile length. Two out of three studies have reported a shorter anogenital distance (a marker of androgen action during the masculinisation programming window, ∼8-14 weeks of gestation) in male infants antenatally exposed to paracetamol. One study has described a dose-dependent relationship between maternal paracetamol consumption and earlier female (but not male) attainment of puberty. Such epidemiological analyses are complicated by various factors, including method of paracetamol exposure assessment (usually retrospective self-report), variation in diagnostic accuracy, selection bias, confounding by clinical indication, and demographic/genetic differences between geographically separated populations. There is an urgent need for stronger evidence in this area, from both relevant experimental studies and large, carefully-designed prospective studies. In the meantime, a precautionary attitude to gestational paracetamol usage should be considered as the evidence for clinically significant reproductive effects in humans is limited.

Using Experimental Models to Decipher the Effects of Acetaminophen and NSAIDs on Reproductive Development and Health

Nonsteroidal anti-inflammatory drugs (NSAIDs), such as aspirin (acetylsalicylic acid), diclofenac and ibuprofen (IBU), and analgesic drugs, such as acetaminophen (APAP, or paracetamol), are widely used to treat inflammation and pain. APAP and IBU are over-the-counter drugs and are among the most commonly taken drugs in the first trimester of pregnancy, even in combination. Furthermore, these drugs and their metabolites are released in the environment, and can be frequently detected in wastewater, surface water, and importantly in drinking water. Although their environmental concentrations are much lower than the therapeutics doses, this suggests an uncontrolled low-dose exposure of the general population, including pregnant women and young children, two particularly at risk populations. Epidemiological studies show that exposure to these molecules in the first and second trimester of gestation can favor genital malformations in new-born boys. To investigate the cellular, molecular and mechanistic effects of exposure to these molecules, ex vivo studies with human or rodent gonadal explants and in vivo experiments in rodents have been performed in the past years. This review recapitulates recent data obtained in rodent models after in utero or postnatal exposure to these drugs. The first part of this review discusses the mechanisms by which NSAIDs and analgesics may impair gonadal development and maturation, puberty development, sex hormone production, maturation and function of adult organs, and ultimately fertility in the exposed animals and their offspring. Like other endocrine disruptors, NSAIDs and APAP interfere with endocrine gland function and may have inter/transgenerational adverse effects. Particularly, they may target germ cells, resulting in reduced quality of male and female gametes, and decreased fertility of exposed individuals and their descendants. Then, this review discusses the effects of exposure to a single drug (APAP, aspirin, or IBU) or to combinations of drugs during early embryogenesis, and the consequences on postnatal gonadal development and adult reproductive health. Altogether, these data may increase medical and public awareness about these reproductive health concerns, particularly in women of childbearing age, pregnant women, and parents of young children.

Eicosanoid Biosynthesis in Male Reproductive Development: Effects of Perinatal Exposure to NSAIDs and Analgesic Drugs

Increasing rates of infertility associated with declining sperm counts and quality, as well as increasing rates of testicular cancer are contemporary issues in the United States and abroad. These conditions are part of the Testicular Dysgenesis Syndrome, which includes a variety of male reproductive disorders hypothesized to share a common origin based on disrupted testicular development during fetal and neonatal stages of life. Male reproductive development is a highly regulated and complex process that relies on an intricate coordination between germ, Leydig, and Sertoli cells as well as other supporting cell types, to ensure proper spermatogenesis, testicular immune privilege, and endocrine function. The eicosanoid system has been reported to be involved in the regulation of fetal and neonatal germ cell development as well as overall testicular homeostasis. Moreover, non-steroidal anti-inflammatory drugs (NSAIDs) and analgesics with abilities to block eicosanoid synthesis by targeting either or both isoforms of cyclooxygenase enzymes, have been found to adversely affect male reproductive development. This review will explore the current body of knowledge on the involvement of the eicosanoid system in male reproductive development, as well as discuss adverse effects of NSAIDs and analgesic drugs administered perinatally, focusing on toxicities reported in the testis and on major testicular cell types. Rodent and epidemiological studies will be corroborated by findings in invertebrate models for a comprehensive report of the state of the field, and to add to our understanding of the potential long-term effects of NSAID and analgesic drug administration in infants.

Long-Term Safety of Prenatal and Neonatal Exposure to Paracetamol: A Systematic Review

Introduction: Paracetamol is the most commonly used antipyretic and analgesic in pregnancy. It is also increasingly used off-label in the neonatal intensive care unit. Despite the frequent use of paracetamol, concerns have been raised regarding the high variability in neonatal dosing regimens and the long-term safety of early life exposure. Objective: To investigate the available evidence on the long-term safety of prenatal and neonatal paracetamol exposure. Methods: We conducted a systematic search of the electronic databases Ovid Medline, Ovid Embase and Web of Science from inception to August 2021 for original research studies of any design that described the use of paracetamol in the prenatal or neonatal (within the first four weeks of life) periods and examined the occurrence of neurodevelopmental, atopic or reproductive adverse outcomes at or beyond birth. Results: We identified 1313 unique articles and included 30 studies in the final review. Of all studies, 27 (90%), two (7%) and one (3%) were on the long-term safety of prenatal, neonatal and both prenatal and neonatal exposure, respectively. Thirteen (46%), 11 (39%) and four (15%) studies examined neurodevelopmental, atopic and reproductive outcomes. Eleven (100%), 11 (100%), and three (27%) studies on prenatal exposure reported adverse neurodevelopmental, atopic and reproductive outcomes. Only one study found a possible correlation between neonatal paracetamol exposure and long-term adverse outcomes. Conclusions: The available evidence, although limited, suggests a possible association between prenatal paracetamol exposure and an increased risk of neurodevelopmental, atopic and reproductive adverse outcomes. There is an immediate need for robust data on the long-term safety of paracetamol exposure in the prenatal and neonatal periods.

Paracetamol use during pregnancy - a call for precautionary action

Paracetamol (N-acetyl-p-aminophenol (APAP), otherwise known as acetaminophen) is the active ingredient in more than 600 medications used to relieve mild to moderate pain and reduce fever. APAP is widely used by pregnant women as governmental agencies, including the FDA and EMA, have long considered APAP appropriate for use during pregnancy when used as directed. However, increasing experimental and epidemiological research suggests that prenatal exposure to APAP might alter fetal development, which could increase the risks of some neurodevelopmental, reproductive and urogenital disorders. Here we summarize this evidence and call for precautionary action through a focused research effort and by increasing awareness among health professionals and pregnant women. APAP is an important medication and alternatives for treatment of high fever and severe pain are limited. We recommend that pregnant women should be cautioned at the beginning of pregnancy to: forego APAP unless its use is medically indicated; consult with a physician or pharmacist if they are uncertain whether use is indicated and before using on a long-term basis; and minimize exposure by using the lowest effective dose for the shortest possible time. We suggest specific actions to implement these recommendations. This Consensus Statement reflects our concerns and is currently supported by 91 scientists, clinicians and public health professionals from across the globe.

Endocrine disruptors and the male reproductive system

In recent years, there has been an increased incidence in several of the most common reproductive disorders, including hypospadias and cryptorchidism in newborns, and testicular cancer and lower sperm quality in young adult males. In addition, the timing of puberty has also changed over time. Although the cause of these reproductive effects is a matter of intense debate, a link with the presence of ubiquitous compounds in the environment, or the exposure to specific groups of medications during foetal life, has been suggested. Results from epidemiological and experimental studies, as well as clinical observations in humans indicate that endocrine-disrupting chemicals may be associated with those disorders. In this review, we will summarize the results of epidemiological studies and experimental studies utilising human testicular cells or tissue. Due to increasing public interest and the recently published data, the main focus will be on the effects of prenatal exposure to mild analgesics.

Using administrative healthcare database records to study trends in prescribed medication dispensed during pregnancy in Belgium from 2003 to 2017

PURPOSE

The aim of this study was to describe trends in medication prescriptions dispensed during pregnancy in Belgium using administrative healthcare database records from a representative sample of the Belgian population.

METHODS

Pregnant women were identified with reimbursement codes associated with the delivery of a baby. Data were extracted for three study periods, each over 3 years: 2003-2005, 2009-2011, and 2015-2017. The age-standardized prevalence of dispensed medications during pregnancy were computed and logistic regression models were used to evaluate the trends in prevalence across the study periods. The most frequently dispensed medications were listed for each study period.

RESULTS

The study included 23 912 pregnancies. The age-standardized prevalence of pregnant women with at least one dispensed medication increased across the three study periods from 81.8.% to 89.3%. The median number and interquartile range of the different medications dispensed during pregnancy rose from 2 (1-6) to 3 (1-7) between the first and last study periods. In the 2015-2017 period, the most frequently dispensed medications during pregnancy included progesterone (25.5%), paracetamol (17.8%), and amoxicillin (17.1%). The data also showed an increasing trend for the dispensation of ibuprofen and ketorolac during pregnancy across the three study periods.

CONCLUSIONS

The prevalence of prescribed medications dispensed during pregnancy increased in Belgium from 2003 to 2017 with high proportion for Progesterone and Antibiotics. Utilization of certain nonsteroidal anti-inflammatory drugs (NSAIDs) increased between 2003 and 2017, despite recommendations to avoid them.

Role of the Abcg2 transporter in plasma levels and tissue accumulation of the anti-inflammatory tolfenamic acid in mice

The Breast Cancer Resistance Protein (BCRP/ABCG2) is an ATP-binding cassette efflux transporter that is expressed in the apical membrane of cells from relevant tissues involved in drug pharmacokinetics such as liver, intestine, kidney, testis, brain and mammary gland, among others. Tolfenamic acid is an anti-inflammatory drug used as an analgesic and antipyretic in humans and animals. Recently, tolfenamic acid has been repurposed as an antitumoral drug and for use in chronic human diseases such as Alzheimer. The aim of this work was to study whether tolfenamic acid is an in vitro Abcg2 substrate, and to investigate the potential role of Abcg2 in plasma exposure, secretion into milk and tissue accumulation of this drug. Using in vitro transepithelial assays with cells transduced with Abcg2, we showed that tolfenamic acid is an in vitro substrate of Abcg2. The in vivo effect of this transporter was tested using wild-type and Abcg2^-/- mice, showing that after oral and intravenous administration of tolfenamic acid, its area under the plasma concentration-time curve in Abcg2^-/- mice was between 1.7 and 1.8-fold higher compared to wild-type mice. Abcg2^-/- mice also showed higher liver and testis accumulation of tolfenamic acid after intravenous administration. In this study, we demonstrate that tolfenamic acid is transported in vitro by Abcg2 and that its plasma levels as well as its tissue distribution are affected by Abcg2, with potential pharmacological and toxicological consequences.

Intrauterine Exposure to Acetaminophen and Adverse Developmental Outcomes: Epidemiological Findings and Methodological Issues

PURPOSE OF REVIEW

Acetaminophen (or paracetamol) is one of the most commonly used medications during pregnancy. We reviewed recent epidemiological evidence regarding intrauterine exposure to acetaminophen and risk for asthma, neurodevelopment disorders, and reproductive health in childhood.

RECENT FINDINGS

An increasing number of cohort studies have suggested that maternal use of acetaminophen during pregnancy was associated with increased risk for asthma; neurodevelopmental disorders, especially ADHD and behavioral problems; and genital malformations in the offspring. Oxidative stress and inflammation or endocrine effects are plausible shared biological mechanisms for the exposure to influence multiple developmental outcomes. We discussed methodological challenges that can threaten the validity of these observational data, including confounding and measurement errors. Novel statistical methods and research designs that can be used to mitigate these issues were introduced. Given the high prevalence of use, findings regarding intrauterine exposure to acetaminophen on multiple child health outcomes raise concerns. Research on causal and non-causal mechanisms that might explain these associations should be a priority.

A toolkit for the application of placental-fetal molecular biomarkers in epidemiologic studies of the fetal origins of chronic disease

Purpose of review

In this review, we provide essential background knowledge and an analytical framework for the application of placental-fetal molecular biomarkers in fetal origins chronic disease epidemiology. The widely available and highly quantitative placental hormone human chorionic gonadotropin (hCG) is used as an example. hCG is currently used for diagnosing fetal genetic disorders; yet it can and should be expanded to understanding the fetal origins of chronic diseases. We provide justification and methods to do this.

Recent findings

Ten papers published in the last 5 years were identified with supportive findings relevant to the application of biomarkers of hCG in epidemiologic studies on the developmental origins of health and disease (DOHaD).

Summary

There is increasing and consistent evidence that placental-fetal biomarkers may be highly informative in observational studies, as exemplified by hCG, with the correct approaches for measurement and data analysis.

Over-the-counter analgesics during pregnancy: a comprehensive review of global prevalence and offspring safety

BACKGROUND

Analgesia during pregnancy is often necessary. Due to their widespread availability, many mothers opt to use over-the-counter (OTC) analgesics. Those analgesic compounds and their metabolites can readily cross the placenta and reach the developing foetus. Evidence for safety or associations with adverse health outcomes is conflicting, limiting definitive decision-making for healthcare professionals.

OBJECTIVE AND RATIONALE

This review provides a detailed and objective overview of research in this field. We consider the global prevalence of OTC analgesia during pregnancy, explain the current mechanistic understanding of how analgesic compounds cross the placenta and reach the foetus, and review current research on exposure associations with offspring health outcomes.

SEARCH METHODS

A comprehensive English language literature search was conducted using PubMed and Scopus databases. Different combinations of key search terms were used including 'over-the-counter/non-prescription analgesics', 'pregnancy', 'self-medication', 'paracetamol', 'acetaminophen', 'diclofenac', 'aspirin', 'ibuprofen', 'in utero exposure', 'placenta drug transport', 'placental transporters', 'placenta drug metabolism' and 'offspring outcomes'.

OUTCOMES

This article examines the evidence of foetal exposure to OTC analgesia, starting from different routes of exposure to evidence, or the lack thereof, linking maternal consumption to offspring ill health. There is a very high prevalence of maternal consumption of OTC analgesics globally, which is increasing sharply. The choice of analgesia selected by pregnant women differs across populations. Location was also observed to have an effect on prevalence of use, with more developed countries reporting the highest consumption rates. Some of the literature focuses on the association of in utero exposure at different pregnancy trimesters and the development of neurodevelopmental, cardiovascular, respiratory and reproductive defects. This is in contrast to other studies which report no associations.

WIDER IMPLICATIONS

The high prevalence and the challenges of reporting exact consumption rates make OTC analgesia during pregnancy a pressing reproductive health issue globally. Even though some healthcare policy-making authorities have declared the consumption of some OTC analgesics for most stages of pregnancy to be safe, such decisions are often based on partial review of literature. Our comprehensive review of current evidence highlights that important knowledge gaps still exist. Those areas require further research in order to provide pregnant mothers with clear guidance with regard to OTC analgesic use during pregnancy.

Effect of environmental and pharmaceutical exposures on fetal testis development and function: a systematic review of human experimental data

BACKGROUND

Overall, the incidence of male reproductive disorders has increased in recent decades. Testicular development during fetal life is crucial for subsequent male reproductive function. Non-genomic factors such as environmental chemicals, pharmaceuticals and lifestyle have been proposed to impact on human fetal testicular development resulting in subsequent effects on male reproductive health. Whilst experimental studies using animal models have provided support for this hypothesis, more recently a number of experimental studies using human tissues and cells have begun to translate these findings to determine direct human relevance.

OBJECTIVE AND RATIONALE

The objective of this systematic review was to provide a comprehensive description of the evidence for effects of prenatal exposure(s) on human fetal testis development and function. We present the effects of environmental, pharmaceutical and lifestyle factors in experimental systems involving exposure of human fetal testis tissues and cells. Comparison is made with existing epidemiological data primarily derived from a recent meta-analysis.

SEARCH METHODS

For identification of experimental studies, PubMed and EMBASE were searched for articles published in English between 01/01/1966 and 13/07/2018 using search terms including ‘endocrine disruptor’, ‘human’, ‘fetal’, ‘testis’, ‘germ cells’, ‘testosterone’ and related search terms. Abstracts were screened for selection of full-text articles for further interrogation. Epidemiological studies involving exposure to the same agents were extracted from a recent systematic review and meta-analysis. Additional studies were identified through screening of bibliographies of full-texts of articles identified through the initial searches.

OUTCOMES

A total of 25 experimental studies and 44 epidemiological studies were included. Consistent effects of analgesic and phthalate exposure on human fetal germ cell development are demonstrated in experimental models, correlating with evidence from epidemiological studies and animal models. Furthermore, analgesic-induced reduction in fetal testosterone production, which predisposes to the development of male reproductive disorders, has been reported in studies involving human tissues, which also supports data from animal and epidemiological studies. However, whilst reduced testosterone production has been demonstrated in animal studies following exposure(s) to a variety of environmental chemicals including phthalates and bisphenol A, these effects are not reproduced in experimental approaches using human fetal testis tissues.

WIDER IMPLICATIONS

Direct experimental evidence for effects of prenatal exposure(s) on human fetal testis development and function exists. However, for many exposures the data is limited. The increasing use of human-relevant models systems in which to determine the effects of environmental exposure(s) (including mixed exposures) on development and function of human tissues should form an important part of the process for assessment of such exposures by regulatory bodies to take account of animal–human differences in susceptibility.

Maternal exposure to ibuprofen can affect the programming of the hypothalamus of the male offspring

Ibuprofen, a non-steroidal anti-inflammatory drug, inhibits the activity of cyclooxygenase enzyme, leading to reduction in Prostaglandin E₂ (PGE₂) production. Due to the importance of PGE₂ in promoting the brain masculinization in male fetus, this study aimed to evaluate the effects of in utero and lactational exposure to ibuprofen and their late repercussions on reproductive parameters in male rats. Pregnant rats were exposed to ibuprofen (10, 30 or 60 mg/kg) or vehicle (control group) per gavage daily from gestational day 15 to day 21 after birth, and late reproductive effects were assessed during the sexual development and in the reproductive adult life in the male offspring. Males exposed to ibuprofen had a decrease in body weight and anogenital distance, as well as a delay in the ages of testicular descent and preputial separation. In adulthood, there was a decrease in the Leydig cells nuclei volume, testosterone levels and percentage of normal sperm morphology. All animals exposed to ibuprofen presented male copulatory behavior, however, in the presence of another male, they also presented a female-typical behavior. Maternal exposure to ibuprofen during the sensitive windows of brain development adversely impacted the reproductive parameters of male rats, suggesting an incomplete masculinization of the hypothalamus.

Which chemicals should be grouped together for mixture risk assessments of male reproductive disorders?

There is concern about cumulative exposures to compounds that disrupt male sexual differentiation in foetal life, leading to irreversible effects in adulthood, including declines in semen quality, testes non-descent, malformations of the penis and testis cancer. Traditional chemical-by-chemical risk assessment approaches cannot capture the likely cumulative health risks. Past efforts of focusing on combinations of phthalates, a subgroup of chemicals suspected of contributing to these risks, do not go far enough, as they ignore the contribution of other types of chemicals. With the aim of providing criteria for the inclusion of additional chemicals in mixture risks assessments for male reproductive health, this paper examines the mechanisms of action of various chemicals capable of disrupting male sexual differentiation. An Adverse Outcome Pathway (AOP) network for malformations of the male reproductive system is constructed that includes new findings about the role of disruptions of prostaglandin signalling. This network is used to identify pathways that converge at critical nodal points to produce down-stream adverse effects. From this knowledge, combinations of chemicals with different mechanisms of action are predicted that should result in cumulative effects. These predictions are then mapped against evidence from experimental mixture studies with relevant combinations. From the outcome of this analysis it is concluded that cumulative assessment groups for male reproductive health risks should not only include phthalates but also comprise androgen receptor (AR) antagonists, chemicals capable of disrupting steroid synthesis, InsL3 production, prostaglandin signalling and co-planar polychlorinated dibenzo-dioxins together with other dioxin-like compounds. This list goes far beyond what has been suggested previously. A minimum set of chemicals to be assessed together with phthalates includes pesticides such as vinclozolin, prochloraz, procymidone, linuron, the pain killers paracetamol, aspirin and ibuprofen, pharmaceuticals such as finasteride, ketoconazole, and the lipid-lowering drug simvastin, poly-chlorinated dibenzo-dioxins and other dioxin-like pollutants and phenolics such as bisphenol A and butylparaben. AOP network analyses are essential to overcome difficulties in establishing groupings of chemicals for mixture risk assessments that derive from a narrow focus on mechanisms and modes of action.

The Use of Medication in Pregnancy

BACKGROUND

Drug safety has the highest priority in the treatment of pregnant women, as any effect on fetal development will not be immediately evident, and the harm that ensues may have lifelong adverse consequences.

METHODS

This review is based on pertinent publications retrieved by a selective literature search and on expert assessment on the basis of the current evidence.

RESULTS

The teratogenic and fetotoxic drugs that are most important in their magnitude of effect and/or frequency of exposure are discussed, along with their characteristic effects. For each of the main indications for drug treatment during pregnancy, the current drugs of choice are stated, regardless of their approval status for use by pregnant women. Drugs are designated as "tolerable" in pregnan- cy if there is currently no reliable evidence of a human teratogenic effect but the state of the evidence is still inadequate for a conclusive determination. Such drugs can be given, in consideration of the risks and benefits, in case the drugs of choice are out of the question. Unplanned pregnancies arising in women who are taking "tolerable" drugs do not necessitate the immediate switch or discontinuation of the drug. On the other hand, drugs with known teratogenic or fetotoxic effects are desig- nated as "contraindicated." For any pregnant woman exposed to such a drug, the risk must be assessed individually, and a risk management strategy must be determined.

CONCLUSION

For most indications for drug treatment in pregnant women, drugs are available with adequate clinical experience supporting drug safety. In all fields of medicine, drug safety information for pregnant women needs to be stated more precisely and in a manner more suitable for clinical application; moreover, the explanation to the patient must enable her to assess the risk realistically, but should not arouse undue anxiety. Drug safety in pregnancy demands the continuous collec- tion of observational data, so that risks can be assessed as precisely as possible and false suspicions can be laid to rest, both for new drugs and for those that have already been in longstanding use. To this end, the Pharmacovigilance Institute (Pharmakovigilanz- und Beratungszentrum, PVZ) for Embryotoxicology critically assesses the current state of the evidence and carries out its own relevant observational studies.

Chronic Pain Prevalence and Exposures during Pregnancy

Pregnant women with chronic pain present a unique clinical challenge for both chronic pain and obstetrical providers, and clinical guidelines do not exist. The present study describes the prevalence and management of chronic pain during pregnancy in a perinatal mood disorder clinic. A retrospective chart review of pregnant women who presented to the Women's Mental Health Program at the University of Arkansas for Medical Sciences (UAMS) for an initial evaluation from July 2013 to June 2016 was conducted to obtain demographic and medical information, including pharmacological exposures. Data are described using the mean and standard deviation for continuous data and frequency for categorical data. Pain complaints and medications are presented as counts and percentages. Differences between women with and without chronic pain were assessed by t-tests for continuous variables and chi-square analysis for categorical variables. Of the 156 pregnant women, chronic pain conditions were reported by 44 (28.2%). The most common chronic pain complaints included neck and/or back pain (34.1%) and headaches (31.8%). Of subjects with chronic pain, 95.5% were taking at least one prescription medication (mean = 2.6 ± 2.1, range of 0-10). Acetaminophen (43.2%) and opioids (43.2%) were the most common. The complexity of managing maternal benefits of treatment with the risks of fetal exposures presents a uniquely challenging clinical scenario for healthcare providers.

Prenatal Exposure to Acetaminophen and Overweight in Childhood

OBJECTIVE

Acetaminophen (paracetamol), a medication commonly used in pregnancy, has hormonal effects, as has been suggested in experimental studies. Developmental exposure to endocrine disruptors could predispose individuals to weight gain. This study evaluated the associations between prenatal acetaminophen exposure and overweight in childhood.

METHODS

A total of 30,127 (age 7) and 24,934 (age 11) children in the Danish National Birth Cohort born during 1996 to 2002 were studied. Mothers reported acetaminophen use in telephone interviews conducted during pregnancy, and children's BMI and waist circumference were reported by parents at 7 and 11 years. Differences for BMI z score and waist circumference were estimated, as well as risk ratios for overweight in girls and boys adjusting for indications of use and other confounders.

RESULTS

There were no consistent associations found for prenatal acetaminophen exposure and BMI z score or waist circumference in girls and boys at both ages. Prenatal acetaminophen exposure was associated with overweight in girls at age 11 (risk ratio 1.31, 95% CI: 1.10-1.56, if exposed in all three trimesters; P < 0.001 for cumulative weeks of exposure), but no association was found in boys.

CONCLUSIONS

There was no strong association between prenatal acetaminophen exposure and childhood BMI, but the findings on frequent prenatal exposure to acetaminophen and overweight in girls warrant further investigation.

[Drug safety in pregnancy-a particular challenge]

Drug safety in pregnancy is of utmost importance because prenatal exposure to the unborn child may result in side effects with life-long consequences. Data on their risks in pregnancy are scarce for many drugs. Furthermore, there is often uncertainty how to translate risk data into practice.This article aims to identify tools to improve data ascertainment on exposed pregnancies and their outcome. Using the example of the German Embryotox institute, it is demonstrated how to disseminate drug safety knowledge to healthcare professionals and patients for clinical decision-making.Observational data are the most important basis for drug risk assessment in pregnancy. Such data are collected by Embryotox through the risk consultation process. Prospective cohort studies with comparison cohorts allow to estimate relative risks for birth defects, pregnancy loss, and other developmental anomalies. Retrospectively ascertained adverse drug reactions contribute to identification of distinct pattern of congenital anomalies.Drugs in pregnancy counselling require risk characterization dependent on the individual clinical setting: recommendation of treatment of choice (comparative risk assessment between effective drugs), individual risk estimation after (inadvertent) exposure, and assessment of causal relationship in cases of congenital anomalies. Combining counselling and protocols of pregnancy outcome after drug exposure is optimal to cost-efficiently ascertain data of high quality.Using acetaminophen, valproic acid, AT1-receptor blockers and retinoids as examples, recent discussions on drug risks in pregnancy and their clinical implications are presented.

Acetaminophen use during pregnancy and DNA methylation in the placenta of the extremely low gestational age newborn (ELGAN) cohort

Acetaminophen is considered the safest antipyretic and analgesic medication for pregnant women. However, studies have reported that acetaminophen has endocrine disrupting properties and prenatal exposure has been associated with early life epigenetic changes and later life health outcomes. As the placenta is the central mediator of maternal and fetal interactions, exposure to acetaminophen during pregnancy could manifest as perturbations in the placenta epigenome. Here, we evaluated epigenome-wide cytosine-guanine dinucleotide (CpG) methylation in placental tissue in relation to maternal acetaminophen use during pregnancy in a cohort of 286 newborns born prior to 28 weeks gestation. According to maternal self-report, more than half (166 of 286) of the newborns were exposed to acetaminophen in utero. After adjustment for potential confounders, a total of 42 CpGs were identified to be differentially methylated at a false discovery rate < 0.05, with most displaying increased methylation as it relates to acetaminophen exposure. A notable gene that was significantly associated with acetaminophen is the prostaglandin receptor (PTGDR) which plays an essential role in mediating placental blood flow and fetal growth. Moreover, for 6 of the 42 CpGs, associations of acetaminophen use with methylation were significantly different between male and female placentas; 3 CpG sites were associated with acetaminophen use in the male placenta and 3 different sites were associated with acetaminophen use in the female placenta (P _interaction < 0.2). These findings highlight a relationship between maternal acetaminophen use during pregnancy and the placental epigenome and suggest that the responses for some CpG sites are sex dependent.

Use of Negative Control Exposure Analysis to Evaluate Confounding: An Example of Acetaminophen Exposure and Attention-Deficit/Hyperactivity Disorder in Nurses' Health Study II

Frequent maternal use of acetaminophen in pregnancy has been linked to attention-deficit/hyperactivity disorder (ADHD) in children, but concerns regarding uncontrolled confounding remain. In this article, we illustrate use of the negative control exposure (NCE) approach to evaluate uncontrolled confounding bias in observational studies on pregnancy drug safety and explain the causal assumptions behind the method. We conducted an NCE analysis and evaluated the associations between maternal acetaminophen use during different exposure periods and ADHD among 8,856 children born in 1993-2005 to women enrolled in the Nurses' Health Study II cohort. Information on regular maternal acetaminophen use was collected prospectively in biennial questionnaires. A total of 721 children (8.1%) in the cohort had been diagnosed with ADHD as reported by the mothers. Our NCE analysis suggested that only acetaminophen use at the time of pregnancy was associated with childhood ADHD (odds ratio = 1.34, 95% confidence interval: 1.05, 1.72), and the effect estimates for the 2 NCE periods (about 4 years before and 4 years after the pregnancy) were null. Our findings corroborate those of prior reports suggesting that prenatal acetaminophen exposure may influence neurodevelopment. The lack of an association between acetaminophen use in the pre- and postpregnancy exposure periods and ADHD provides assurance that uncontrolled time-invariant factors do not explain this association.

Acetaminophen (Paracetamol) Exposure During Pregnancy and Pubertal Development in Boys and Girls From a Nationwide Puberty Cohort

This study explored the association between exposure to acetaminophen during pregnancy and pubertal development using data from 15,822 boys and girls in the longitudinal Puberty Cohort, nested within the Danish National Birth Cohort. Use of acetaminophen was reported 3 times during pregnancy and 6 months postpartum. In total, 54% of mothers indicated use at least once during pregnancy. Between 2012 and 2017, sons and daughters provided information on a wide range of pubertal milestones-including Tanner stages, axillary hair growth, and age at menarche or voice break and first ejaculation-every 6 months from 11 years of age until full sexual maturation. Data were analyzed using a regression model for interval-censored data, providing adjusted mean monthly differences in age at attaining the pubertal milestones according to intrauterine cumulative (weeks) and trimester-specific acetaminophen exposure. Our results suggested a tendency towards slightly earlier attainment of almost all studied markers of female pubertal development with increasing number of weeks of exposure (i.e., about 1.5-3 months earlier age at pubic hair, axillary hair, and acne development comparing unexposed with those prenatally exposed for more than 12 weeks). Male pubertal development had no strong association with acetaminophen exposure.

Long-term adverse effects of paracetamol - a review

Paracetamol (acetaminophen) is the most commonly used drug in the world, with a long record of use in acute and chronic pain. In recent years, the benefits of paracetamol use in chronic conditions has been questioned, notably in the areas of osteoarthritis and lower back pain. Over the same period, concerns over the long-term adverse effects of paracetamol use have increased, initially in the field of hypertension, but more recently in other areas as well. The evidence base for the adverse effects of chronic paracetamol use consists of many cohort and observational studies, with few randomized controlled trials, many of which contradict each other, so these studies must be interpreted with caution. Nevertheless, there are some areas where the evidence for harm is more robust, and if a clinician is starting paracetamol with the expectation of chronic use it might be advisable to discuss these side effects with patients beforehand. In particular, an increased risk of gastrointestinal bleeding and a small (~4 mmHg) increase in systolic blood pressure are adverse effects for which the evidence is particularly strong, and which show a degree of dose dependence. As our estimation of the benefits decreases, an accurate assessment of the harms is ever more important. The present review summarizes the current evidence on the harms associated with chronic paracetamol use, focusing on cardiovascular disease, asthma and renal injury, and the effects of in utero exposure.

Prenatal paracetamol exposure and child neurodevelopment: A review

BACKGROUND

The non-prescription medication paracetamol (acetaminophen, APAP) is currently recommended as a safe pain and fever treatment during pregnancy. However, recent studies suggest a possible association between APAP use in pregnancy and offspring neurodevelopment.

OBJECTIVES

To conduct a review of publications reporting associations between prenatal APAP use and offspring neurodevelopmental outcomes.

METHODS

Relevant sources were identified through a key word search of multiple databases (Medline, CINAHL, OVID and TOXNET) in September 2016. All English language observational studies of pregnancy APAP and three classes of neurodevelopmental outcomes (autism spectrum disorder (ASD), attention deficit hyperactivity disorder (ADHD), and intelligence quotient (IQ)) were included. One reviewer (AZB) independently screened all titles and abstracts, extracted and analyzed the data.

RESULTS

64 studies were retrieved and 55 were ineligible. Nine prospective cohort studies fulfilled all inclusion criteria. Data pooling was not appropriate due to heterogeneity in outcomes. All included studies suggested an association between prenatal APAP exposure and the neurodevelopmental outcomes; ADHD, ASD, or lower IQ. Longer duration of APAP use was associated with increased risk. Associations were strongest for hyperactivity and attention-related outcomes. Little modification of associations by indication for use was reported.

CONCLUSIONS

Together, these nine studies suggest an increased risk of adverse neurodevelopmental outcomes following prenatal APAP exposure. Further studies are urgently needed with; precise indication of use and exposure assessment of use both in utero and in early life. Given the current findings, pregnant women should be cautioned against indiscriminate use of APAP. These results have substantial public health implications.

Transgenerational Effects of Toxicants: An Extension of the Daphnia 21-day Chronic Assay?

The assessment of transgenerational effects should be incorporated in standard chronic toxicity protocols for the sake of a realistic extrapolation of contaminant effects to the population level. We propose a simple add-on to the standard 21-day chronic Daphnia magna assay, allowing the assessment of the reproductive performance of the offspring (F₁ generation) born from the first clutch of the parental (F₀) generation. The extended generational assay was performed simultaneously with the standard reproduction assay. With this design, we evaluated the lethal, reproductive, and transgenerational effects of four widespread and extensively used substances: a biocide/anti-fouling (copper sulphate), an industrial oxidizing agent (potassium dichromate), a pharmaceutical (paracetamol), and a quaternary ammonium compound (benzalkonium chloride). Benzalkonium chloride was the most toxic in terms of lethality, whereas paracetamol, copper sulphate, and potassium dichromate caused deleterious effects in the reproductive performance of exposed D. magna. Adverse effects in the fitness of the daughter (F₁) generation were observed in the case of maternal exposure to paracetamol and copper sulphate, although they were not very pronounced. These findings highlight the usefulness of our approach and reinforce the view-shared by other authors-of the need for a generalised formal assessment of the transgenerational effects of pollutants.

Effects of Exposure to Acetaminophen and Ibuprofen on Fetal Germ Cell Development in Both Sexes in Rodent and Human Using Multiple Experimental Systems

BACKGROUND

Analgesic exposure during pregnancy may affect aspects of fetal gonadal development that are targeted by endocrine disruptors.

OBJECTIVES

We investigated whether therapeutically relevant doses of acetaminophen and ibuprofen affect germ cell (GC) development in human fetal testes/ovaries using in vitro and xenograft approaches.

METHODS

First-trimester human fetal testes/ovaries were cultured and exposed to acetaminophen or ibuprofen (7 d). Second-trimester human fetal testes were xenografted into mice and exposed to acetaminophen (1 or 7 d), or ibuprofen (7 d). To determine mechanism of action, a human GC tumor–derived cell line (NTera2) exhibiting fetal GC characteristics was used in addition to in vitro and in vivo rat models.

RESULTS AND DISCUSSION

Gonocyte (TFAP2C⁺) number was reduced relative to controls in first-trimester human fetal testes exposed in vitro to acetaminophen (-28%) or ibuprofen (-22%) and also in ovaries exposed to acetaminophen (-43%) or ibuprofen (-49%). Acetaminophen exposure reduced gonocyte number by 17% and 30% in xenografted second-trimester human fetal testes after treatment of host mice for 1 or 7 d, respectively. NTera2 cell number was reduced following exposure to either analgesic or prostaglandin E₂ (PGE₂) receptor antagonists, whereas PGE₂ agonists prevented acetaminophen-induced reduction in NTera2 cell number. Expression of GC pluripotency genes, and genes that regulate DNA/histone methylation, also differed from controls following analgesic and PGE₂ receptor antagonist exposures. Gene expression changes were observed in rat fetal testis/ovary cultures and after in vivo acetaminophen exposure of pregnant rats. For example, expression of the epigenetic regulator TET1, was increased following exposure to acetaminophen in human NTera2 cells, rat fetal testis/ovary cultures, and in fetal testes and ovaries after in vivo exposure of pregnant rats, indicating translatability across experimental models and species.

CONCLUSIONS

Our results demonstrate evidence of PGE₂-mediated effects of acetaminophen and ibuprofen on GC/NTera2 cells, which raises concerns about analgesic use during human pregnancy that warrant further investigation. https://doi.org/10.1289/EHP2307.

Prevalence of xenobiotic substances in first-trimester blood samples from Danish pregnant women: a cross-sectional study

OBJECTIVE

The aim of this study was to investigate the prevalence of xenobiotic substances, such as caffeine, nicotine and illicit drugs (eg, cannabis and cocaine), in blood samples from first-trimester Danish pregnant women unaware of the screening.

DESIGN

A cross-sectional study examined 436 anonymised residual blood samples obtained during 2014 as part of the nationwide prenatal first-trimester screening programme. The samples were analysed by ultra performance liquid chromatography with high-resolution time-of-flight mass spectrometry.

SETTING

An antenatal clinic in a Danish city with 62 000 inhabitants, where >95% of pregnant women joined the screening programme.

PRIMARY AND SECONDARY OUTCOME MEASURES

The prevalence and patterns of caffeine, nicotine, medication and illicit drug intake during the first trimester of pregnancy.

RESULTS

The prevalence of prescription and over-the-counter drug detection was 17.9%, including acetaminophen (8.9%) and antidepressants (3.0%), of which citalopram (0.9%) was the most frequent. The prevalence of illegal drugs, indicators of smoking (nicotine/cotinine) and caffeine was 0.9%, 9.9%, and 76.4%, respectively. Only 17.4% of women had no substance identified in their sample.

CONCLUSIONS

This study emphasises the need for further translational studies investigating lifestyle habits during pregnancy, as well as the underlying molecular mechanisms through which xenobiotic substances may affect placental function and fetal development.

Assessing the impact of in-utero exposures: potential effects of paracetamol on male reproductive development

Human male reproductive disorders (cryptorchidism, hypospadias, testicular cancer and low sperm counts) are common and some may be increasing in incidence worldwide. These associated disorders can arise from subnormal testosterone production during fetal life. This has resulted in a focus on in-utero environmental influences that may result in reproductive effects on the offspring in later life. Over recent years, there has been a dramatic increase in the scientific literature describing associations between in-utero environmental exposures (eg, industrial chemicals and pharmaceuticals) and subsequent reproductive outcomes in male offspring. This includes studies investigating a potential role for in-utero analgesic exposure(s) on the fetal testis; however, providing definitive evidence of such effects presents numerous challenges. In this review, we describe an approach to assessing the potential clinical relevance of in-utero (and postnatal) environmental exposures on subsequent male reproductive function using exposure to the analgesic paracetamol as an example.

Male urinary paracetamol and semen quality

The endocrine-disrupting properties of paracetamol have been previously demonstrated in rodent studies of abnormal sperm morphology and diminished testosterone production, in addition to epidemiologic studies of diminished couple fecundity. In this study, we examined the relationship between paracetamol and its metabolite p-aminophenol quantified in a single spot urine and semen quality among 501 male partners of couples planning for pregnancy. Men provided a urine specimen and two fresh semen samples collected approximately one month apart and underwent 24-h analysis for 35 semen quality parameters. Paracetamol and p-aminophenol were quantified in urine by ultra-high-performance liquid chromatography coupled with an electrospray triple quadrupole mass spectrometry. The relationship between natural-log-transformed urinary paracetamol and p-aminophenol rescaled by their standard deviation and 21 Box-Cox-transformed, 14 non-transformed semen parameters was assessed using linear mixed-effects models. The median concentrations (IQR) of urinary paracetamol and p-aminophenol were 15.5 ng/mL (5.44, 73.5) and 978 ng/mL (500, 1596), respectively. Following adjustment for creatinine and age, a 1-standard deviation increase in log-transformed urinary paracetamol was associated with a reduction in beat cross-frequency and an increase in DNA fragmentation [β (95% CI): -0.59 Hz (-1.16, -0.03) and 0.05% (0.01, 0.09), respectively]. These findings were corroborated in models of categorical chemical concentrations; higher concentrations of paracetamol remained associated with reduced beat cross-frequency and increased DNA fragmentation. A 1-standard deviation increase in log-transformed urinary p-aminophenol was associated with a reduction in sperm head area [β (95% CI): -0.1 μm2 (-0.18, -0.02) and width -0.02 μm (-0.04, -0.01)]. However, only the association with sperm head area remained statistically significant in models of p-aminophenol quartiles. Our findings suggest that adult male urinary paracetamol is associated with sperm motility and DNA fragmentation, while the metabolite, p-aminophenol, is predominantly associated with sperm head morphometry.

Perinatal and neonatal use of paracetamol for pain relief

Paracetamol (acetaminophen) is the most widely used drug to treat pain or fever in pregnant women or neonates, but its pharmacokinetics (PK) and pharmacodynamics (PD) warrant a focused analysis. During pregnancy, there is an important increase in paracetamol clearance. Consequently, it is reasonable to anticipate that the analgesic effect of paracetamol will decrease faster, whereas higher doses may result in even higher oxidative toxic metabolites. Therefore, most peripartal PD data relate to multimodal analgesia strategies. In neonates, weight/size is the most relevant covariate of paracetamol PK. This resulted in proposed dosing regimens containing higher doses than currently prescribed in the label for term neonates. Using adequate dosing, paracetamol is a poor procedural analgesic, is effective for mild-to-moderate pain, and has morphine-sparing effects. Short-term safety has been well documented, and there is active research investigating the potential association between paracetamol exposure and atopy, fertility, and neurobehavior.

Risk factors for cryptorchidism

Undescended testis - known as cryptorchidism - is one of the most common congenital abnormalities observed in boys, and is one of the few known risk factors for testicular cancer. The key factors that contribute to the occurrence of cryptorchidism remain elusive. Testicular descent is thought to occur during two hormonally-controlled phases in fetal development - between 8-15 weeks (the first phase of decent) and 25-35 weeks gestation (the second phase of descent); the failure of a testis to descend permanently is probably caused by disruptions to one or both of these phases, but the causes and mechanisms of such disruptions are still unclear. A broad range of putative risk factors have been evaluated in relation to the development of cryptorchidism but their plausibility is still in question. Consistent evidence of an association with cryptorchidism exists for only a few factors, and in those cases in which evidence seems unequivocal the factor is likely to be a surrogate for the true causal exposure. The relative importance of each risk factor could vary considerably between mother-son pairs depending on an array of genetic, maternal, placental and fetal factors - all of which could vary between regions. Thus, the role of causative factors in aetiology of cryptorchidism requires further research.

Analgesic use in pregnancy and male reproductive development

PURPOSE OF REVIEW

Male reproductive disorders are common and increasing in incidence in many countries. Environmental factors (including pharmaceuticals) have been implicated in the development of these disorders. This review aims to summarize the emerging epidemiological and experimental evidence for a potential role of in-utero exposure to analgesics in the development of male reproductive disorders.

RECENT FINDINGS

A number of epidemiological studies have demonstrated an association between in utero exposure to analgesics and the development of cryptorchidism, although these findings are not consistent across all studies. Where present, these associations primarily relate to exposure during the second trimester of pregnancy. In vivo and in vitro experimental studies have demonstrated variable effects of exposure to analgesics on Leydig cell function in the fetal testis of rodents, particularly in terms of testosterone production. These effects frequently involve exposures that are in excess of those to which humans are exposed. Investigation of the effects of analgesics on human fetal testis have also demonstrated effects on Leydig cell function. Variation in species, model system, dosage and timing of exposure is likely to contribute to differences in the findings between studies.

SUMMARY

There is increasing evidence for analgesic effects on the developing testis that have the potential to impair male reproductive function. However, the importance of these findings in relation to human-relevant exposures and the risk of male reproductive disorders remain unclear.

Analgesia use during pregnancy and risk of cryptorchidism: a systematic review and meta-analysis

STUDY QUESTION

Are boys who are born to mothers who use analgesics during pregnancy at increased risk of cryptorchidism compared to those born to mothers who do not take analgesia?

SUMMARY ANSWER

In this systematic review and meta-analysis of 10 published studies, we observed only weak evidence of an association between analgesia use during pregnancy and risk of cryptorchidism in the son.

WHAT IS KNOWN ALREADY

Concentrations of analgesia relevant to human exposure have been implicated as causing endocrine disturbances in the developing foetal testis. However, when viewed collectively there appears to be conflicting evidence regarding an association between maternal use of analgesics and development of cryptorchidism.

STUDY DESIGN, SIZE, DURATION

A systematic review and meta-analysis of studies on analgesia use during pregnancy and risk of cryptorchidism was performed. The search terms used were (analges* OR paracetamol OR acetaminophen) AND (cryptorchidism OR cryptorchism OR undescended test* OR non-descended test* OR non descended test*) for the databases Ovid Medline, Embase, Scopus and Web of Science. The search included all published articles up until 23 May 2016 and no limits were set in terms of language.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Abstracts were screened by one reviewer to remove irrelevant studies, with a 10% random sample of these verified by a second reviewer. The full text of all remaining papers was assessed by two reviewers. Abstracts included in the final analysis were studies which reported associations between the exposure (analgesia) and the outcome (cryptorchidism). Studies were only included if data were provided from which summary associations (odds ratios (ORs) or relative risks) and their 95% CIs could be calculated, or if summary associations were provided by the authors themselves. For each included study, two reviewers independently extracted study meta-data in line with PRISMA recommendations. We assessed study quality and potential for bias using the criteria outlined in the Newcastle-Ottawa Quality Assessment Scale, but did not determine a quality score. Two reviewers independently assessed study quality against these criteria.

MAIN RESULTS AND THE ROLE OF CHANCE

After screening 350 manuscripts, 10 were included in our review (5 case-control studies, 5 cohort studies). We observed weak evidence of an association between ever use of analgesia and risk of cryptorchidism (pooled crude OR: 1.11, 95% CI: 1.00-1.23), with case-control studies revealing a marginally stronger association (1.23, 95% CI: 0.85-1.78) than cohort studies (1.09, 95% CI: 0.97-1.22). We observed weak evidence of a dose-response relationship between increasing weeks of analgesia exposure and risk of cryptorchidism, as well as weak evidence of an effect of timing on analgesia exposure and risk of cryptorchidism. Assessment of study quality via the Newcastle-Ottawa criteria revealed little (if any) evidence of substantial bias that may have meaningfully affected a given study's results.

LIMITATIONS, REASONS FOR CAUTION

While confounding does not appear to be important, misclassification of the exposure is possibly an important source of measurement error in this context. The systematic review is open to reporting bias. Owing to scant data, no meta-analyses for two key questions (relating to dose-response and timing of exposure) could be performed. Medications were grouped based on their common effect and this offers little insight into the relation between specific types of analgesia and cryptorchidism. Finally, there are limitations in assuming that analgesia use reported by mothers is synonymous with actual intrauterine exposure.

WIDER IMPLICATIONS OF THE FINDINGS

The ubiquity of analgesia use during pregnancy makes this exposure particularly important from a population health perspective. About 9 of the 10 studies were conducted in Europe or USA, limiting generalizability of our observations. While the observations from our systematic review and meta-analysis suggest that analgesia use during pregnancy is not strongly associated with cryptorchidism development in the son, they also highlight the need for further detailed assessments of this relationship.

STUDY FUNDING/COMPETING INTEREST(S)

This study was funded by the Health Research Council of New Zealand (reference #: 14/052). The authors have no conflict of interest to declare.

REGISTRATION NUMBER

CRD42016041414.

Ibuprofen results in alterations of human fetal testis development

Among pregnant women ibuprofen is one of the most frequently used pharmaceutical compounds with up to 28% reporting use. Regardless of this, it remains unknown whether ibuprofen could act as an endocrine disruptor as reported for fellow analgesics paracetamol and aspirin. To investigate this, we exposed human fetal testes (7–17 gestational weeks (GW)) to ibuprofen using ex vivo culture and xenograft systems. Ibuprofen suppressed testosterone and Leydig cell hormone INSL3 during culture of 8–9 GW fetal testes with concomitant reduction in expression of the steroidogenic enzymes CYP11A1, CYP17A1 and HSD17B3, and of INSL3. Testosterone was not suppressed in testes from fetuses younger than 8 GW, older than 10–12 GW, or in second trimester xenografted testes (14–17 GW). Ex vivo, ibuprofen also affected Sertoli cell by suppressing AMH production and mRNA expression of AMH, SOX9, DHH, and COL2A1. While PGE2 production was suppressed by ibuprofen, PGD2 production was not. Germ cell transcripts POU5F1, TFAP2C, LIN28A, ALPP and KIT were also reduced by ibuprofen. We conclude that, at concentrations relevant to human exposure and within a particular narrow ‘early window’ of sensitivity within first trimester, ibuprofen causes direct endocrine disturbances in the human fetal testis and alteration of the germ cell biology.