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.

First-trimester exposure to metformin and risk of birth defects: a systematic review and meta-analysis.

BACKGROUND: Metformin is generally considered a non-teratogenic drug; however, only a few studies specifically designed to assess the rate of congenital anomalies after metformin use have been published in the literature. The objects of the present study were to review all of the prospective and retrospective studies reporting on women treated with metformin at least during the first trimester of their pregnancy and to estimate the overall rate of major birth defects. METHODS: Databases were searched for English language articles until December 2013. Inclusion criteria for the meta-analysis were: a case group of women with PCOS or pre-pregnancy type 2 diabetes and first-trimester exposure to metformin; a disease-matched control group which was not exposed to metformin or other oral anti-diabetic agents; and a list of the major anomalies in both the study and the control groups. A random effects model was used for the meta-analysis of data, using odds ratios. Studies not fulfilling the inclusion criteria for the meta-analysis but reporting relevant data on major malformations in women diagnosed with PCOS were then used to estimate the overall birth defects rate. RESULTS: Meta-analysis of nine controlled studies with women affected by PCOS detected that the rate of major birth defects in the metformin-exposed group was not statistically increased compared with the disease-matched control group and that there was no significant heterogeneity among the studies. The metformin-exposed sample was composed of 351 pregnancies and the OR of major birth defects was 0.86 (95% confidence interval: 0.18-4.08; Pheterogeneity = 0.71). By evaluating all of the non-overlapping PCOS studies reported in the literature, even those without an appropriate control group, the overall rate of major anomalies was 0.6% in the sample of 517 women who discontinued the therapy upon conception or confirmation of pregnancy and 0.5% in the sample of 634 women who were treated with metformin throughout the first trimester of their pregnancy. Regarding type 2 diabetic women, we did not identify a sufficient number of studies with metformin exposure during the first trimester to proceed with the meta-analysis. CONCLUSIONS: There is currently no evidence that metformin is associated with an increased risk of major birth defects in women affected by PCOS and treated during the first trimester. However larger ad hoc studies are warranted in order to definitely confirm the safety and efficacy of this drug in pregnancy.

Pregnancy outcome in women exposed to antiepileptic drugs: teratogenic role of maternal epilepsy and its pharmacologic treatment.

Infants born to epileptic women treated with antiepileptic drugs (AEDs) have an increased risk of major congenital malformations (MCMs). In order to determine the role of maternal epilepsy we conducted a prospective cohort study on three cohorts of pregnant women: (i) 385 epileptic women treated with AEDs, (ii) 310 non-epileptic women treated with AEDs, (iii) 867 healthy women not exposed to AEDs (control group). The rate of MCMs in the epileptic group (7.7%) was not statistically higher than in the non-epileptic one (3.9%) (p=0.068). The rate in the first group was higher compared to the control group (p=0.001), while the rate in the second one was not (p=0.534). Our data confirm that AEDs therapy is the main cause of the increased risk of malformations in the offspring of epileptic women; however a teratogenic role of the maternal epilepsy itself cannot be excluded.

Genetic susceptibility to teratogens: state of the art.

There is evidence that the susceptibility to the teratogenic effect of drugs within human populations varies extremely from one individual to another, even after identical exposures. One of the factors that may explain these interindividual differences is the genetic makeup in the pharmacokinetics and pharmacodynamics of the respective drugs. In fact, both maternal and embryonic/fetal genotypes can affect placental transport, absorption, metabolism, distribution and receptor binding of an agent, influencing its teratogenicity. We have reviewed the literature and commented on the reported correlations between genetic factors and drug-induced birth defects. There is still a clear lack of knowledge regarding this issue and the available data are often conflicting. However, the identification of specific polymorphisms associated with predisposition to teratogenesis may allow in the future the development of personalized non-teratogenic therapies for pregnant women.

The outcomes of pregnancy in women exposed to the new macrolides in the first trimester: a prospective, multicentre, observational study.

BACKGROUND: Macrolides are a group of commonly prescribed antibiotics. There is some doubt surrounding the use of the newer macrolides in pregnancy. OBJECTIVE: The present study aimed to compare outcomes of pregnancies exposed to the new macrolides clarithromycin, azithromycin and roxithromycin with non-teratogenic preparations. METHODS: In this prospective, multinational, multicentre, controlled, observational study, information was obtained either from pregnant women or their healthcare professionals who contacted their local teratogen information services in Italy, Israel, the Czech Republic, the Netherlands and Germany seeking information after exposure to macrolides. The comparison group included women or their healthcare professional who contacted these centres with questions regarding known non-teratogenic preparations. Information on obstetric and other background parameters was collected at enrollment; after delivery, subjects or their healthcare professionals were contacted to ascertain pregnancy outcome parameters and other exposures through the remainder of the pregnancy. RESULTS: A total of 608 women exposed to macrolides during pregnancy were enrolled; 511 of the exposures occurred during the first trimester. The comparison group comprised 773 women exposed to non-teratogenic preparations during the first trimester of pregnancy. No significant difference in the rate of major congenital malformations was found between the study group and the comparison group (3.4% vs 2.4%; p = 0.36; odds ratio (OR) 1.42; 95% CI 0.70, 2.88) or in the rate of cardiovascular malformations (1.6% vs 0.9%; p = 0.265; OR 1.91; 95% CI 0.63, 5.62). No significant differences were found between subgroups of macrolides in the rates of major congenital malformations or cardiac malformations, although for azithromycin this was of borderline significance. CONCLUSIONS: This study, in agreement with earlier smaller studies, suggests that the new macrolides do not pose a significantly increased risk of major congenital malformations or cardiac malformations.

Pharmacologic treatment of hyperthyroidism during pregnancy.

Clinical hyperthyroidism has been associated with an increased risk of maternal, fetal, and neonatal complications. The available antithyroid drugs are methimazole/carbimazole and propylthiouracil. Several case reports and some epidemiologic studies suggest that methimazole/carbimazole exposure during the first trimester of pregnancy is associated with an increased risk of congenital malformations, including ectodermal anomalies, choanal atresia, esophageal atresia, and omphalocele. However, the absolute risk appears to be very small, and it remains unclear whether the association is driven by the maternal disease, the medication, or the combination of both factors. Propylthiouracil exposure has not been associated with an increased risk of congenital malformations and is the recommended drug during the first trimester of pregnancy. Since propylthiouracil-induced hepatotoxicity has been reported in approximately 0.1% of exposed adults and the number of case-reports of severe liver injury is increasing, treatment with low dose methimazole during the second and third trimesters should be considered. Until now, there has been no evidence that children prenatally exposed to methimazole/carbimazole or propylthiouracil have an increased risk of neurodevelopmental delay.

Pregnancy outcome after in utero exposure to angiotensin converting enzyme inhibitors or angiotensin receptor blockers.

OBJECTIVE: To examine first trimester safety of angiotensin-converting-enzyme-inhibitors (ACEIs) or angiotensin-receptor-blockers (ARBs). STUDY DESIGN: Prospective observational cohort regarding pregnancy ACEI/ARBs-exposure including contacts to two Teratology Information Services in Israel (1994-2007) and Italy (1990-2008), with two comparison groups: (1) exposed to other antihypertensives (OAH) (2) after non-teratogenic exposure (NTE) in similar time frames. RESULTS: 252 ACEI/ARBs-exposed, 256 OAH-exposed and 495 NTE-exposed pregnancies were followed-up. The rate of major congenital anomalies was comparable between the groups (8/190, 4.2%, ACEI/ARB; 9/212, 4.2%, OAH; 18/471, 3.8% NTE; p = 0.954) among first trimester exposed pregnancies. The median gestational age at delivery was two weeks earlier, rate of preterm deliveries more than 2-fold higher, and median birth weight more than 200 g lower in the ACEI/ARB and OAH groups compared to the NTE group. CONCLUSION: The present study suggests that ACEI/ARBs are not major teratogens when used in the first trimester, and can reassure women with similar exposures.

Migraine therapy during pregnancy and lactation.

IMPORTANCE OF THE FIELD: Migraine affects about 25% of women during childbearing years but few data are available about the risks connected with most antimigraine drugs during pregnancy. AREAS COVERED IN THIS REVIEW: In this report, we review the available data, mainly obtained from published studies, toxicology databases and clinical guidelines, on migraine treatment during pregnancy and lactation. WHAT THE READER WILL GAIN: The following drugs should be preferred for the treatment of acute migraine attacks in pregnant women: paracetamol, NSAIDs and sumatriptan. Migraine prophylaxis should be undertaken when patients experience at least three prolonged severe attacks a month that are particularly incapacitating or unresponsive to symptomatic therapy and likely to result in complications. Non-pharmacologic approaches should be preferred, but if they are not effective, preventive treatment should include low doses of ß-blockers and amitriptyline. TAKE HOME MESSAGE: Migraine treatment is often necessary because maternal and fetal risks related to acute attacks may be more harmful than the therapy itself, especially if they are frequent, severe and associated with nausea, anorexia, vomiting, hypotension or dehydration. If non-pharmacologic treatments do not alleviate migraine symptoms, only few drugs can be used during pregnancy and lactation.

Treatment of hyperthyroidism in pregnancy and birth defects.

CONTEXT: Clinical hyperthyroidism is not uncommon in pregnancy, with a reported prevalence of 0.1 to 0.4%. The available antithyroid drugs are propylthiouracil and methimazole/carbimazole. OBJECTIVES: In this report we examined the association of both drugs with congenital malformations using data from the International Clearinghouse for Birth Defects Surveillance and Research. DESIGN: The study used a case-affected control analysis and included 18,131 cases with malformations and reported first-trimester exposure to medication. A total of 127 subjects were born to mothers with known first-trimester antithyroid drug exposure. RESULTS: Among the 52 groups of malformations that were analyzed, situs inversus ± dextrocardia, isolated unilateral kidney a/dysgenesis, and cardiac outflow tract defects were associated with prenatal exposure to propylthiouracil based on three, two, and five cases, respectively. Prenatal exposure to methimazole/carbimazole was significantly associated with choanal atresia, omphalocele, and total situs inversus ± dextrocardia (P < 0.01). CONCLUSIONS: Further studies are required to exhaustively evaluate the associations between propylthiouracil and birth defects because of the low number, the lack of biological plausibility, and the possibility of underdiagnosis. Association between methimazole/carbimazole exposure and omphalocele and choanal atresia is consistent with previous reports and definitely suggests that these malformations could be part of a specific, even if rare, embryopathy.

First trimester diclofenac exposure and pregnancy outcome.

OBJECTIVE: To assess the safety of diclofenac during pregnancy. METHODS: A prospective observational cohort study, evaluating follow-up data of women who contacted Teratology Information Services to get counseling. The exposed group included 145 pregnant women who were exposed to diclofenac between the 5th and the 14th gestational week. A contemporary control group (501 women) was randomly selected from among patients who contacted Teratology Information Services with regard to exposures to agents known not to be teratogenic during a similar period of pregnancy. RESULTS: Major birth malformations were not more common in the study group than in the control group (p=0.07). CONCLUSION: Our study suggests that the use of diclofenac is relatively safe during the first trimester of pregnancy and the studied sample size makes it possible to exclude a risk of congenital malformation higher than 3.3, with a power of 80%.

Bisphosphonates in patients with autoimmune rheumatic diseases: Can they be used in women of childbearing age?

Autoimmune rheumatic diseases (ARD) are prevalent in women during their childbearing age. For their treatment, high doses of corticosteroid (CS) for long-term periods are often required, increasing the risk of bone loss. According to recent guidelines, bisphosphonates (BP) should be used as first line treatment to prevent CS induced osteoporosis. However, due to their long-term release from bone and their ability to cross the placenta, it has been suggested to avoid BP in women during their fertile years. BP seem to decrease foetus bone length in pregnant animals, but not in humans, at least, when they are administered at therapeutic dosage. BP are embryo toxic in animals when used at high dosage. In a systematic literature review, we found 58 women treated with BP close before or during pregnancy, showing no related congenital malformations. However, the Unit of Clinical and Epidemiological Genetics in University of Padova collected ten cases of women treated with BP during pregnancy, reporting 20% of congenital malformations. Thus, we suggest to avoid BP during pregnancy and caution with their use in fertile women. When they have to be given before pregnancy, specific affinities of the BP have to be considered to plan the washout period beforehand.

Is CFTR 621+3 A>G a cystic fibrosis causing mutation?

The 621+3 A>G variant of the CFTR gene was initially detected in four Greek patients with a severe form of cystic fibrosis, and it is reported to impair CFTR mRNA splicing. We present three lines of evidence that argue against the pathogenicity of this variant. First, its allelic frequency in the Italian population was 0.4%. Even considering the lowest value in the confidence interval we would expect 10% of Italian CF patients to be heterozygotes for this variant, whereas it has been reported only in one patient (0.04% of Italian CF patients). Second, expression of the 621+3 A>G variant in HeLa cells using a hybrid minigene showed that 39.5+/-1.1% of transcripts were correctly spliced, indicating that its effects on mRNA splicing are similar to those of the CFTR intron 8 5T variant, associated with congenital bilateral absence of vas deferens (CBAVD), but not with CF. Third, we have identified an asymptomatic individual who harbored the 621+3 A>G variant in trans with the Q552X mutation. Because 621+3 A>G is often included in population-screening programs, this information is critical to provide adequate counseling to patients. Further work should be aimed at investigating whether this variant may have a role in CBAVD or atypical CF.

Therapy of inflammatory bowel diseases in pregnancy and lactation.

Inflammatory bowel diseases (IBDs) are a group of disorders characterised by chronic or relapsing inflammation within the gastrointestinal tract of variable severity. A chronic medication is often needed and management of fertile women is a crucial point because of the possible adverse effects associated with the administered drugs and the disease itself. The risk of pregnancy-related complications and the disease behaviour during pregnancy depends mainly on disease activity at time of conception. So, it is very important to plan the pregnancy and reach and maintain a clinical remission of the disease before conception. Drugs usually used in IBD treatment include 5- aminosalicylic acid compounds, corticosteroids, azathioprine and 6-mercaptopurine, cyclosporine A, mesalazine, and antibiotics such as metronidazole and ciprofloxacin. Management of IBD in pregnancy at present is not standardised or supported by strong evidence. In this report, we summarise the available data, mainly derived from retrospective and case-control studies, about IBD management in pregnancy, focusing mostly on the safety of drugs during gestation and peripartum.

First-trimester itraconazole exposure and pregnancy outcome: a prospective cohort study of women contacting teratology information services in Italy.

BACKGROUND: Itraconazole is an effective fungal treatment; however, there are few human data on prenatal exposure. OBJECTIVES: To evaluate the major malformation rate in itraconazole prenatally exposed infants. The secondary objective includes evaluation of the pregnancy outcome. METHODS: A prospective cohort study was conducted from January 2002 to October 2006 in women who called two Italian Teratology Information Services (TIS). Pregnant women who were exposed to itraconazole during the first trimester and gave informed consent were matched with a contemporary group of pregnant women who contacted the TIS because they had undergone a non-teratogenic drug exposure during the first trimester. Information was obtained via a structured questionnaire at the time of the initial call to the TIS and no earlier than 1 month after delivery. A trained operator conducted the interview. The main outcome measure was information about major congenital anomalies, type of delivery, birth weight, and any pregnancy or neonatal complications. RESULTS: Data were collected on 206 women who called the TIS because of first-trimester exposure to itraconazole, and 207 controls. There were no significant differences in terms of major congenital anomalies in the exposed group versus the control group (3/163 [1.8%] vs 4/190 [2.1%], respectively). There was no statistical difference in the rate of vaginal delivery between the exposed and control groups (101/162 [62.3%] vs 102/190 [53.8%]), premature birth (11/162 [6.8%] vs 15/190 [7.9%]), low birth weight (1/152 [0.7%] vs 4/175 [2.3%]) and high birth weight (10/152 [6.5%] vs 7/175 [4.0%], respectively). The rates of live births (163/206 [79.1%] vs 190/207 [91.8%]), spontaneous abortion (23/206 [11.2%] vs 10/207 [4.8%]) and termination of pregnancy (19/206 [9.2%] vs 7/207 [3.4%] in the exposed and control groups, respectively) were significantly different (p < 0.05). CONCLUSION: First-trimester itraconazole-exposed infants were not at increased risk of major congenital anomalies, but the rates of spontaneous and induced abortion were higher in the exposed group versus the control group. Larger studies are warranted to confirm these observations.

Iodine status in pregnancy: role of dietary habits and geographical origin.

OBJECTIVES: A study was conducted on iodine status during pregnancy and its dependence on dietary habits, racial and geographical origin, and time since arrival in Italy. DESIGN AND METHODS: We enrolled 322 consecutive pregnant women: 217 Italians, 62 Eastern Europeans and 43 from Northern and Central Africa. All women completed a food frequency questionnaire on their dietary habits. The urinary iodide concentration (UIC) was determined in spot morning urine samples. RESULTS: In the group as a whole, the median UIC was 83 microg/l; the UIC was < 50 in 33% and of 150 microg/l or more in 27%; it was significantly lower in Africans and Eastern Europeans than in Italians (medians 45 and 46 vs. 100 microg/l, respectively, P = 0.005). For the foreign women, there was a significant correlation between UIC and time since arrival in Italy (r = 0.22, P = 0.02). A significant link emerged between UIC and cow's milk intake (P = 0.0001). Iodine supplements were used by 40% of the women, and UIC were higher in those who did so than in those who did not (median 103 vs. 75 microg/l, P = 0.03), particularly if the latter did not drink milk (median 98 vs. 42 microg/l, P = 0.01). Multivariate analysis showed that milk was the only variable influencing UIC (OR 1.29, P = 0.0005). CONCLUSIONS: (i) Iodine levels are too low among pregnant women in our region, and particularly in foreign women. (ii) Cow's milk intake is their main source of iodine. (iii) Iodine supplementation is mandatory during pregnancy, particularly for women do not drink milk.

Paroxetine and fluoxetine in pregnancy: a prospective, multicentre, controlled, observational study.

AIMS: Recent studies have suggested a possible association between maternal use of selective serotonin reuptake inhibitors (SSRIs) in early pregnancy and cardiovascular anomalies. The aim of the present study was to evaluate the teratogenic risk of paroxetine and fluoxetine. METHODS: This multicentre, prospective, controlled study evaluated the rate of major congenital anomalies after first-trimester gestational exposure to paroxetine, fluoxetine or nonteratogens. RESULTS: We followed up 410 paroxetine, 314 fluoxetine first-trimester exposed pregnancies and 1467 controls. After exclusion of genetic and cytogenetic anomalies, there was a higher rate of major anomalies in the SSRI groups compared with the controls [paroxetine 18/348 (5.2%), fluoxetine 12/253 (4.7%) and controls 34/1359 (2.5%)]. The main risk applied to cardiovascular anomalies [paroxetine 7/348 (2.0%), crude odds ratio (OR) 3.47, 95% confidence interval (CI) 1.13, 10.58; fluoxetine 7/253 (2.8%), crude OR, 4.81 95% CI 1.56, 14.71; and controls 8/1359 (0.6%)]. On logistic regression analysis only cigarette smoking of >or=10 cigarettes day(-1) and fluoxetine exposure were significant variables for cardiovascular anomalies. The adjusted ORs for paroxetine and fluoxetine were 2.66 (95% CI 0.80, 8.90) and 4.47 (95% CI 1.31, 15.27), respectively. CONCLUSION: This study suggests a possible association between cardiovascular anomalies and first-trimester exposure to fluoxetine.

Pregnancy outcome of women exposed to azathioprine during pregnancy.

BACKGROUND: Azathioprine (AZP) interferes with nucleic acid synthesis and is teratogenic in animals. In view of the paucity of information on the use of AZP during pregnancy we investigated this subject in a prospective, controlled, multicenter study. Our objective was too determine whether exposure to AZP during pregnancy increases the risk for major malformations and to determine the effect on pregnancy outcome. METHODS: Pregnant women on AZP who contacted one of seven teratogen information services were compared to a cohort of pregnant women who contacted two of the seven teratogen information services and took nonteratogenic treatments during their pregnancy. RESULTS: Follow-up was completed on 189 women in the AZP group and compared to 230 women in the control group. The rate of major malformations did not differ between groups with six neonates in each; the AZP rate was 3.5% and the control group rate was 3.0% (p = .775; OR 1.17; CI: 0.37, 3.69). The mean birth weight and gestational age were lower in the AZP group (2,995 g vs. 3,252 g [p = .001, difference of mean: 257, 95% CI: 106.3, 408.1] and 37.8 weeks vs. 39.1 weeks [p = .001, difference of mean: 1.3, 95% CI: .5, 2.0], respectively). The AZP group had more cases of prematurity (21.4% vs. 5.2% [p < .001; OR 4.0; 95% CI: 2.0, 8.06]) and low birth weight (23% vs. 6.0% [p < .001; OR 3.81; 95% CI: 2.0, 7.2]). CONCLUSIONS: These results suggest that AZP (50-100 mg/day) does not triple the rate of birth defects; however, it is associated with lower birth weight, gestational age, and prematurity. Larger studies are needed to confirm these observations.

Are congenital anorectal malformations more frequent in newborns conceived with assisted reproductive techniques?

One of the major concerns about ART is the risk of birth defects in children born after in vitro fertilization. We report on a cohort of consecutive children affected with anorectal malformation (ARM) requiring surgical correction in which we found a significantly high proportion (Odds ratio 13.31, 95% confidence limits 4.0-39.6) of children born after ART. Our data is in agreement with the result of a recent epidemiological study in Sweden. Further studies are necessary to define the risk and identify the causes, if any. At present, couples undergoing ART should be informed of the general risk of congenital anomalies, of which, ARM can be suggested as an example.