Uranium concentration in umbilical cord may increase the risk for orofacial clefts.

BACKGROUND: Orofacial clefts (OFCs) are common kind of congenital malformations. The teratogenicity of uranium (U) has been documented in animal study that maternal exposure to U can increase incidence of external malformations including cleft palate. However, there is limited evidence of the association of in utero exposure to U with OFCs risk in humans. OBJECTIVE: This study aimed to investigate the association between in utero exposure to U and the risk of OFCs and its subtypes. METHOD: All subjects were from a case-control study in Shanxi Province, northern China. Eighty-four OFCs cases and 142 healthy controls were included in this study. We used U concentration in umbilical cord as biomarkers to represent intrauterine exposure, which was detected by inductively coupled plasma mass spectrometry. Unconditional logistic regression was used to investigated the association between U level and the risk of OFCs and its subtypes. RESULTS: The median of U concentration in umbilical cord is 0.745 ng/g in case group and 0.455 ng/g in control group. When the U concentration was divided into two categories, high level of U exposure increased the risk of OFCs (OR: 2.08, 95% CI: 1.13-3.86) and its subtype cleft lip with cleft palate (CLP) (OR: 2.72, 95% CI: 1.21-6.14). When divided into three categories, high level of U elevated the risk for OFCs (OR: 2.40, 95% CI: 1.14-5.06) and CLP (OR: 3.04, 95% CI: 1.20-7.74). Meanwhile, a dose-response relationship between the U concentration and the risk of total OFCs (P for trend = 0.009) and CLP (P for trend = 0.007) was found. CONCLUSION: Our study found that in utero exposure to high level of U was associated with increased risk of OFCs and its subtype CLP.

Levels of uranium and thorium in maternal scalp hair and risk of orofacial clefts in offspring.

Uranium and thorium are common radioactive elements that exist in the environment. However, few environmental epidemiological studies have focused on their possible effects on congenital malformations. Here, we explored the association between uranium and thorium concentrations in maternal scalp hair grown from 3 months before to 3 months after conception, namely during the periconceptional period and the risk of orofacial clefts (OFCs) in offspring. Our study included 153 women whose pregnancies were affected by OFCs (cases) and 601 women who delivered infants without birth defects (controls) from four provinces in China. Face-to-face interviews were used to collect sociodemographic characteristics with a structured questionnaire. Concentrations of uranium and thorium in maternal scalp hair grown during the periconceptional period were detected using inductively coupled plasma-mass spectrometry. The risk of OFCs in association with higher concentrations of the two radioactive elements was estimated using odds ratios (ORs) and 95% confidence intervals (CIs) while adjusting for potential confounding factors. The levels of uranium and thorium in maternal hair were in agreement with the published literature. After adjusting for several confounders, the ORs of thorium in the highest, upper, and lower quartile versus the lowest quartile were 2.63 (95% CI, 1.41-4.92), 1.98 (95% CI, 1.03-3.79), and 2.73 (95% CI, 1.46-5.12), respectively. No association was found between levels of uranium and the risk of OFCs. Maternal periconceptional exposure to thorium may be a risk factor for OFCs in offspring.

Association of Parental Environmental Exposures and Supplementation Intake with Risk of Nonsyndromic Orofacial Clefts: A Case-Control Study in Heilongjiang Province, China.

The aim of present study was to check the possible association of potential parental environmental exposures and maternal supplementation intake with the risk of nonsyndromic orofacial clefting (NSOC). A retrospective study comprised 499 cases and 480 controls was conducted in Heilongjiang Province. Chi-square analysis and unconditional multiple logistic regression were used in the study. The results showed that maternal history of fever and the common cold without fever (ORCL/P = 3.11 and 5.56, 95%CI: 1.67-5.82 and 2.96-10.47, ORCPO = 3.31 and 8.23, 95%CI: 1.58-6.94 and 4.08-16.95), paternal smoking and alcohol consumption (ORCL/P = 2.15 and 5.04, 95%CI: 1.37-3.38 and 3.00-8.46, ORCPO = 1.82 and 4.40, 95%CI: 1.06-3.13 and 2.50-7.74), maternal exposure to organic solvents, heavy metals, or pesticides (ORCL/P = 6.07, 5.67 and 5.97, 95%CI: 1.49-24.76, 1.34-24.09 and 2.10-16.98, ORCPO = 10.65, 7.28 and 3.48, 95%CI: 2.54-44.67, 1.41-37.63 and 1.06-11.46) and multivitamin use during the preconception period (ORCL/P = 0.06, 95%CI: 0.02-0.23, ORCPO = 0.06, 95%CI: 0.01-0.30) were associated with cleft lip or without cleft palate (CL/P) and cleft palate only (CPO). Maternal history of skin disease and negative life events (ORCL/P = 12.07 and 1.67, 95%CI: 1.81-80.05 and 1.95-2.67) were associated with CL/P. Some potential parental hazardous exposures during the periconception period and maternal use of multivitamins during the preconception period were associated with risk of NSOC.

Prenatal exposure to nitrosatable drugs, vitamin C, and risk of selected birth defects.

UNLABELLED: Nitrosatable drugs, such as secondary or tertiary amines and amides react with nitrite in an acidic environment to form N-nitroso compounds, teratogens in animal models. Vitamin C is a known nitrosation inhibitor. METHODS: Using data from the National Birth Defects Prevention Study, we assessed nitrosatable drug exposure and vitamin C intake during the first trimester among 11,606 case-mothers of infants with oral clefts, limb deficiencies (LDs), or congenital heart defects and 6807 control-mothers of infants without major birth defects during 1997-2005. Daily intake of vitamin C was estimated from maternal interviews that elicited information about supplement use and dietary intake. RESULTS: With no reported use of nitrosatable drugs as the referent group, a lower odds ratio (OR) was observed for transverse LDs among births to mothers exposed to secondary amine drugs and daily vitamin C supplementation (adjusted odds ratio [aOR] 1.2, 95% confidence interval [CI] 0.83-1.8) compared with women taking these drugs and no supplementation (aOR 2.7, 95% CI 1.5-4.6). The OR for longitudinal LDs associated with secondary amine exposure was lower with daily dietary vitamin C intake ≥85 mg (aOR 1.2, 95% CI 0.68-2.0) compared with <85 mg (aOR 1.9, 95% CI 1.2-3.1). Daily vitamin C supplementation in combination with higher dietary vitamin C intake reduced associations between nitrosatable drug exposures and limb deficiencies and atrial septal defects not otherwise specified. CONCLUSION: Prenatal dietary and vitamin C supplement intake may diminish the association between nitrosatable drug exposure during pregnancy and selected birth defects.

Maternal consumption of coffee and caffeine-containing beverages and oral clefts: a population-based case-control study in Norway.

A large, population-based case-control study of facial clefts was carried out in Norway between 1996 and 2001. The study included 573 cases -- 377 with cleft lip with or without cleft palate and 196 with cleft palate only -- and 763 randomly selected controls. Maternal consumption of coffee and other caffeine-containing beverages in early pregnancy was recorded shortly after birth. Compared with that for no coffee consumption, the adjusted odds ratios for cleft lip with or without cleft palate were 1.39 (95% confidence interval: 1.01, 1.92) for less than 3 cups a day and 1.59 (95% confidence interval: 1.05, 2.39) for 3 cups or more. Coffee consumption was not associated with risk of cleft palate only (for > or = 3 cups vs. none, adjusted odds ratio = 0.96, 95% confidence interval: 0.55, 1.67). Tea consumption was associated with a reduced odds ratio of both cleft lip with or without cleft palate and cleft palate only. There was little evidence of an association between caffeine exposure and clefts when all sources of caffeine were considered. Adjustment for known confounding factors in general had minor effects on risk estimates. Still, the authors could not rule out the possibility of uncontrolled confounding by factors associated with the habit of drinking coffee.

Maternal antioxidant supplementation does not reduce the incidence of phenytoin-induced cleft lip and related malformations in rats.

There is considerable evidence that phenytoin-induced birth defects in the rat are a consequence of a period of bradycardia and hypoxia in the embryos. Experiments were designed to test the hypothesis that phenytoin-induced birth defects result from free-radical damage to the embryos during the reoxygenation period posthypoxia. Female rats (>9 per group) were fed either a control diet or a diet high in antioxidants (vitamins C and E and coenzyme Q(10)) both before and during pregnancy and were then given a teratogenic dose of phenytoin (180 mg/kg) on GD 11. The rats were killed on GD 20 and the fetuses were examined for malformations. The initial results showed that the antioxidant diet had a significant protective effect, with far fewer antioxidant-group fetuses showing cleft lip or maxillary hypoplasia compared with the control group. However, this result was confounded by reduced food intake by the rats fed the antioxidant diet and a significantly lower maternal body weight at the time of phenytoin administration. Since the phenytoin was administered by intraperitoneal injection (i.p.) the control rats received higher absolute doses of phenytoin and it is speculated that this results in higher fetal exposure. A second experiment, in which the rats were pair-fed, failed to demonstrate any protective effect of the high antioxidant diet. These results do not support the reoxygenation hypothesis for phenytoin teratogenesis. An alternative explanation would be hypoxia-induced transcription-related changes resulting in cell cycle arrest and apoptosis.

Low maternal alcohol consumption during pregnancy and oral clefts in offspring: the Slone Birth Defects Study.

BACKGROUND: The association between maternal alcohol consumption during pregnancy and oral clefts in offspring remains unclear. We studied this relation in a case-control surveillance study of birth defects. METHODS: From 1983 to 1997, we recruited 5956 study subjects from greater Boston, Philadelphia, Toronto, and parts of Iowa. The cases were liveborn infants with cleft palate alone (CP; n = 205), cleft lip and palate (CLP; n = 383), cleft lip alone (CL; n = 259), or Pierre-Robin sequence (n = 65). The controls (n = 4272) were infants who had no oral clefts but had one or more of the following defects: malformations of the digestive tract, reproductive organs, abdominal wall, and respiratory tract; chromosomal anomalies; inguinal hernia; tumors; and Mendelian inherited disorders. Based on maternal reports of alcohol consumption during the first 4 months of pregnancy, we derived average weekly consumption, average number of drinks per drinking day, and the maximum number of drinks consumed in a given day. The mothers also provided data on potential confounding or modifying variables, such as vitamin supplement use. RESULTS: There was no relation between maternal alcohol consumption during pregnancy and CL or CP. The odds ratios (ORs) for cleft lip with or without palate (CL/P) were 1.0, 1.1, and 0.9 in women who consumed <1.0, 1.0-2.9, and 3.0 + drinks per week, respectively. These findings did not change when we considered possible modifying effects of vitamin supplement use. CONCLUSIONS: Our findings do not support an association between oral clefts and a low level of alcohol consumption.

Management issues for women with epilepsy: neural tube defects and folic acid supplementation.

For infants exposed to antiepileptic drugs (AEDs) in utero, the risk for congenital malformations is approximately 4 to 6%, twice the rate reported in the general population. A variety of malformations have been reported in association with prenatal exposure to AEDs. However, a particular association of valproate and carbamazepine with neural tube defects (NTDs)--specifically, with spina bifida aperta (SB)--has been identified. The prevalence of SB is approximately 1 to 2% with valproate exposure and 0.5% with carbamazepine. Reported risk factors for NTDs include previous pregnancy with an NTD, maternal insulin-dependent diabetes mellitus, various nutritional deficiencies and occupational exposures, and high prepregnancy weight. Deficiencies of folate have been implicated in the development of birth defects, including NTDs. The value of periconceptional folic acid supplementation for women in the general population is accepted. However, it is unclear whether folic acid supplementation protects against the embryotoxic and teratogenic effects of AEDs because animal and human studies and case reports have shown variable results. Nevertheless, folic acid supplementation is recommended for women with epilepsy as it is for other women of childbearing age. Even with supplementary folic acid, women taking valproate or carbamazepine should undergo perinatal diagnostic ultrasound to rule out NTDs.

Chemical exposure during pregnancy and oral clefts in newborns.

This article presents a literature review on the risk factors for oral clefts (lip and/or palate), emphasizing discussion of maternal exposure to endocrine disruptors. Several studies have identified the risk of cigarette smoking and alcohol consumption, use of anticonvulsant drugs, and exposure to organic solvents. A protective effect has been shown for supplementation with folic acid. As with other chemicals, the risk associated with exposure to sex hormones is still obscure, although some authors describe a moderate risk level. New studies addressing this hypothesis need to be conducted, while the population exposed to these endocrine disrupters is increasing.

Folic acid antagonists during pregnancy and the risk of birth defects.

BACKGROUND: Multivitamin supplementation in pregnant women may reduce the risks of cardiovascular defects, oral clefts, and urinary tract defects in their infants. We evaluated whether the folic acid component of multivitamins is responsible for the reduction in risk by examining the associations between maternal use of folic acid antagonists and these congenital malformations. METHODS: We compared data on exposure to folic acid antagonists that act as dihydrofolate reductase inhibitors and to certain antiepileptic drugs for 3870 infants with cardiovascular defects, 1962 infants with oral clefts, and 1100 infants with urinary tract defects with data for 8387 control infants with malformations the risk of which is not reduced after vitamin supplementation. Mothers were interviewed within six months after delivery about their medication use. RESULTS: The relative risks of cardiovascular defects and oral clefts in infants whose mothers were exposed to dihydrofolate reductase inhibitors during the second or third month after the last menstrual period, as compared with infants whose mothers had no such exposure, were 3.4 (95 percent confidence interval, 1.8 to 6.4) and 2.6 (95 percent confidence interval, 1.1 to 6.1), respectively. The relative risks of cardiovascular defects, oral clefts, and urinary tract defects after maternal exposure to antiepileptic drugs were 2.2 (95 percent confidence interval, 1.4 to 3.5), 2.5 (95 percent confidence interval, 1.5 to 4.2), and 2.5 (95 percent confidence interval, 1.2 to 5.0), respectively. Use of multivitamin supplements containing folic acid diminished the adverse effects of dihydrofolate reductase inhibitors, but not that of antiepileptic drugs. CONCLUSIONS: Folic acid antagonists, which include such common drugs as trimethoprim, triamterene, carbamazepine, phenytoin, phenobarbital, and primidone, may increase the risk not only of neural-tube defects, but also of cardiovascular defects, oral clefts, and urinary tract defects. The folic acid component of multivitamins may reduce the risks of these defects.

[Benzodiazepines and pregnancy]. / Benzodiazépines et grossesse.

The use of benzodiazepines is not negligible in pregnant woman and self-medication is considerable. To investigate the effects on the fetus of benzodiazepines used during pregnancy, we reviewed animal and clinical studies completed with observations of CRPV (Centres Régionaux de Pharmacovigilance). Pooled results indicate that the risk of malformations associated with first-trimester exposure to benzodiazepines remains small. However, in a fetus exposed essentially to long-acting benzodiazepines on a long-term basis, neonatal hypotonicity, failure to feed and/or withdrawal syndrom could be observed.

Increased susceptibility to 6-aminonicotinamide-induced cleft lip of heterozygote Dancer mice.

Dancer heterozygotes (Dc/+) very rarely have cleft lip and show a dancing behaviour due to inner ear defects while homozygotes (Dc/Dc) have cleft lip. Males of the two genotypes Dc/+ and +/+ were mated to C3H strain and R stock females and Dc/+ males to Dc/+ females. On day 10/8 of gestation females were treated with 6-aminonicotinamide (6AN) at either 19 mg/kg or 28.5 mg/kg followed 3 h later by a protective dose of nicotinamide. Controls were untreated. Both 6AN treatments caused a significant increase in cleft lip to between 25% and 29% for crosses of Dc/+ males to C3H and R females whereas crosses with +/+ males gave 0% cleft lip. In the controls the cleft lip frequency was: for Dc/+ X Dc/+ 14%, Dc/+ X C3H 1.4%, and for the other three crosses 0%. The four crosses given the high dose of 6AN and the +/+ X C3H and Dc/+ X R cross at the low dose showed significantly increased resorption rates to between 23% and 47% over the control rates of from 5% to 11%. The presence of the Dc gene increased the susceptibility to cleft lip caused by 6AN.

The association between maternal influenza, drug consumption and oral clefts.

The linkage between potentially teratogenic factors was studied in a material of 599 children with oral clefts and their matched controls. A method based on Yule's Q coefficient describing the degree of association between two dichotomous variables was applied. All factors studied (five groups of drugs taken by the mothers during early pregnancy, maternal influenza and fever) were significantly associated with the birth of children with clefts. The only factor whose association with clefts was explained by linkage to other factors was fever. In addition, the association between clefts and antipyretic analgesics other than salicylates could be partly explained by controlling the intake of salicylates. Although there was a strong association between influenza and consumption of salicylates, the correlation of neither of the two factors with oral clefts could be even partly explained by controlling the other. The method is considered suitable for epidemiological studies of congenital defects.