Incidence and potentiation of external and internal fetal anomalies resulting from chlordiazepoxide and amitriptyline alone and in combination

Society for Maternal-Fetal Medicine Consult Series #68: Sickle cell disease in pregnancy

Pregnant individuals with sickle cell disease have an increased risk of maternal and perinatal morbidity and mortality. However, prepregnancy counseling and multidisciplinary care can lead to favorable maternal and neonatal outcomes. In this consult series, we summarize what is known about sickle cell disease and provide guidance for sickle cell disease management during pregnancy. The following are Society for Maternal-Fetal Medicine recommendations.

Pharmacoethics and pregnancy: Overcoming the therapeutic orphan stigma

There is paucity of evidence to support clinical decision making and counselling related to medication use in pregnancy. Despite multiple efforts from legislative bodies and advocacy groups, the inclusion of pregnant women in clinical drug trials assessing efficacy and safety remains scarce. Pregnancy can be complicated by multiple comorbidities that require pharmacological intervention; these interventions primarily target the pregnant woman but also sometimes have secondary effects for the foetus. The US Food and Drug Administration has issued multiple guidance documents on incorporating pregnant women in clinical trials to aid pharmaceutical companies in designing a protocol to ensure safety and adherence to ethical standards. Advances in paediatric pharmacology studies provide lessons for researchers on the best practice of designing clinical trials with inclusion of patients from special populations. In this review, we present the status of pregnant women in clinical trials, highlighting the ethical stigma and possible future directives.

Fetal teratogenicity in a rhesus macaque (Macaca mulatta): Association with the chronic maternal treatment of amitriptyline

Amitriptyline is a tricyclic antidepressant commonly prescribed in humans for pain and sleep disorders and in non-human primates for self-injurious behaviors. Here, we report a clinical case on the teratogenic effect of maternal-fetal amitriptyline exposure.

Prenatal antidepressant exposure: clinical and preclinical findings

Pharmacological treatment of any maternal illness during pregnancy warrants consideration of the consequences of the illness and/or medication for both the mother and unborn child. In the case of major depressive disorder, which affects up to 10-20% of pregnant women, the deleterious effects of untreated depression on the offspring can be profound and long lasting. Progress has been made in our understanding of the mechanism(s) of action of antidepressants, fetal exposure to these medications, and serotonin's role in development. New technologies and careful study designs have enabled the accurate sampling of maternal serum, breast milk, umbilical cord serum, and infant serum psychotropic medication concentrations to characterize the magnitude of placental transfer and exposure through human breast milk. Despite this progress, the extant clinical literature is largely composed of case series, population-based patient registry data that are reliant on nonobjective means and retrospective recall to determine both medication and maternal depression exposure, and limited inclusion of suitable control groups for maternal depression. Conclusions drawn from such studies often fail to incorporate embryology/neurotransmitter ontogeny, appropriate gestational windows, or a critical discussion of statistically versus clinically significant. Similarly, preclinical studies have predominantly relied on dosing models, leading to exposures that may not be clinically relevant. The elucidation of a defined teratological effect or mechanism, if any, has yet to be conclusively demonstrated. The extant literature indicates that, in many cases, the benefits of antidepressant use during pregnancy for a depressed pregnant woman may outweigh potential risks.

Treatment of anxiety during pregnancy: effects of psychotropic drug treatment on the developing fetus

Pregnancy is a time of great emotional change for a woman, producing increased stress and anxiety. Medication may be required for the treatment of anxiety disorders at this time. Given the fact that psychotropic drugs readily cross the placenta and could have important implications for the developing fetus, it is necessary to balance the possible effects of medication against the potential effects to both the mother and fetus if the anxiety disorder is left untreated. Despite the widespread use of psychotropic drugs such as benzodiazepines and antidepressants during pregnancy, there is a paucity of information regarding the effect of such exposure on the developing fetus. From a review of the literature it is clear that the issue of safety of psychotropic drugs during pregnancy is far from resolved. While some of the findings from animal studies are alarming, these studies cannot be directly extrapolated to humans. In addition, varying sample sizes and multiple drug exposures further complicate interpretation of human studies. Nonpharmacological treatments such as cognitive behavioural therapy should be employed whenever possible for the treatment of anxiety disorders during pregnancy. However, if medication is required pregnant women should be prescribed the lowest dosage for the minimum amount of time.

Multiple chemical exposures: synergism vs. individual exposure levels

Exposure to single chemicals is known to produce congenital malformations in both pregnant animals and humans exposed at sufficiently high intensity. However, real life involves multiple, simultaneous exposures. Using as a database the 43 multiple chemical exposure studies located by Nelson (Teratology 49:33-71; 1994) where synergism was reported, we explored the degree to which such concerns may be realistic from the viewpoint of the current standard developmental toxicity safety evaluation process. Focusing on the assessment of the lowest tested dose of a given agent participating in synergistic activity as compared to its threshold level for eliciting toxicity when administered alone, we found that while the availability of adequate data was limited, all cases, with the possible exception of one, demonstrated synergistic toxic expression only when at least one, and usually both, compounds were used at or above their individual threshold for toxicity. These findings suggest that in animals such phenomena of synergistic chemical interactions are likely to occur only when at least one and more likely both agents are administered at or above their individual threshold for toxicity. To the extent animal studies are predictive of human developmental hazards due to single chemical exposures, available data do not establish multiple chemical exposures as a major human developmental concern.

The outcome of pregnancy in 689 women exposed to therapeutic doses of antidepressants. A collaborative study of the European Network of Teratology Information Services (ENTIS)

The European Network of the Teratology Information Services (ENTIS) has collected and evaluated data on 689 pregnancies in which exposure to tricyclic and nontricyclic antidepressants occurred. Data were collected prospectively from the time of in utero exposure and all the cases were followed up to the first few weeks of postnatal life using standardized procedures. In most cases, no longer term follow-up data were available. Approximately two-thirds of the mothers were on multidrug therapy, and of those, half took a benzodiazepine. About 95% of the patients were exposed during the first trimester. The most striking feature of the pregnancy outcomes is that 97% of live-born babies were morphologically normal. The incidence of spontaneous abortion and late fetal/neonatal deaths were within the normal range. Fourteen live-born babies and one fetus had either major or minor malformations, and six had minor anomalies. However, there was no increase in either a particular type of malformation or a specific pattern of defects. Another 31 infants without malformations had neonatal problems; these were usually associated with chronic multidrug therapy, especially near term. Elective termination of pregnancy occurred more frequently in the multidrug groups (86 out of 488) than in the monotherapy groups (20 out of 201), but data concerning the condition of the fetus are not available in the majority of the cases. Overall, no causal relationship could be established between in utero exposure to antidepressants and adverse pregnancy outcome.

Interactions in developmental toxicology: a literature review and terminology proposal

Developmental toxicologists have investigated the interactive effects from concurrent exposures to a variety of chemical and physical agents, including therapeutic drugs, industrial agents, and some biological organisms or their toxins. Of approximately 160 reports of concurrent exposures reviewed in this paper, about one third report no interactive effects (including additive effects--usually referring to response--as opposed to dose-additivity); another one third report antagonistic effects, and the final third report potentiative or synergistic effects. The quality of the studies is highly variable. Frequently, only small numbers of animals were included, and very few dose levels were evaluated. Maternal toxicity was rarely discussed. Time-effect relationships were examined infrequently. In addition, these studies are also inconsistent in the use of terms to describe interactive effects, and more than 90% of the terms were not in harmony with currently accepted definitions in toxicology. Because interaction studies will continue to be important in the future, this paper proposes uniform usage of terms for additivity and interactions in developmental toxicology: additivity (the combined effect of two or more developmental toxicants approximates the sum of the effects of the agents administered separately); antagonism (the combined effect of two or more agents, one or more of which are present at doses that would be developmentally toxic if given individually, is significantly less than the sum of the effects of the agents administered separately); potentiation (the increased effect of a developmental toxicant by concurrent action of another agent at a dose that is not developmentally toxic); synergism (the combined effect of two or more developmental toxicants is significantly greater than the sum of the effects of each agent administered alone); and, interaction if more precise terminology does not apply.

Embryotoxic and teratogenic effects of interaction of cadmium and lindane in rats

Embryotoxic and teratogenic effects of cadmium and lindane were studied in rats. Cadmium or lindane alone did not produce any significant malformations in the 20 day old foetuses whereas their combination caused significant reduction in the body weight of dams and pups and increased total embryonic deaths. Skeletal deformities like wavy ribs, reduced skull ossification and reduced caudal vertebrae were potentiated in coexposure group. The study indicated that the simultaneous exposure to cadmium and lindane may have more deleterious effects on the developing foetus compared to either alone.