Maternal non-recognition of Down syndrome in black South African infants

Down syndrome (DS), one of the commonest causes of mental retardation in Caucasoids, has only rarely been described in Africa. In previous studies it was suggested that there may be clinical difficulties in making the diagnosis in African neonates. In the present study data were collected by means of a questionnaire administered partly before and partly after a genetic counselling session, to 35 mothers of African infants with DS. The results show that 83% of these mothers did not recognise any facial difference between their affected infant and other normal infants and 57% did not observe any other physical differences. After counselling, 40% of the sample still did not accept that their infant was different from other newborns. Only one mother was aware of infants with similar characteristics. These findings suggest that if mothers themselves cannot see the differences between their DS children and normal children, clinical diagnosis based on physical stigmata may be difficult. Furthermore, acceptance of the diagnosis may be retarded until delayed milestones can be observed in the affected infants.     

Pattern of desynchronized sleep during deprivation and recovery induced in the rat by changes in ambient temperature

The pattern of desynchronized sleep (DS) occurrence in the rat was studied during exposure to an ambient temperature (Ta) of 0 degrees C for 48 h and during a 12 h recovery period at laboratory Ta (23 degrees C) following the first and second 24 h of cold exposure. The exposure to low Ta induces a DS deprivation which is followed, during recovery, by a clear DS rebound. Both the decrease and the following increase in the amount of DS are due to changes in the frequency rather than in the duration of DS episodes. The frequency distribution of the intervals between the end of one DS episode and the beginning of the next (DS interval) has shown that two populations of DS intervals exist, i.e. short DS intervals (3 min). On the basis of this, two types of DS episodes have been identified: the 'single DS episode', which is both preceded and followed by a long DS interval, and the 'sequential DS episode', which is a DS episode occurring within a cluster or a sequence of DS episodes and is characteristically separated by short DS intervals. The occurrence of such sequential DS episodes in a 'DS cluster', allows a high amount of DS to occur without increasing the duration of the DS episode. DS clusters are repressed during cold exposure, when the DS drive is counteracted by the need to thermoregulate, and enhanced during recovery, when the DS drive is unrestrained. In contrast, the occurrence of single DS episodes is much less affected by such different experimental conditions.     

Methylenetetrahydrofolate reductase enzyme polymorphisms as maternal risk for Down syndrome among Turkish women

Advanced maternal age is the only fully accepted risk factor for trisomy 21, while most children with Down syndrome (DS) are born to younger mothers (<35 years). The relationship between chromosomal nondisjunction leading to aneuploidy and folate metabolism has drawn attention in the recent years. In this study, we examined the two polymorphisms in genes encoding the folate metabolizing enzyme methylenetetrahydrofolate reductase (MTHFR), namely, 677C > T and 1298A > C. The prevalence of these variant genotypes in mothers of DS children (case mothers) (n = 152) was compared with controls (n = 91). Frequencies of MTHFR 677C > T genotypes (CC, CT, and TT) and also combination of heterozygous and homozygous variant genotypes (CT or TT) (P = 0.28) demonstrated no difference between the case and control groups. Genotype frequencies of MTHFR 1298A > C (AA, AC, and CC) were similar among the case and control mothers. Variant genotypes of MTHFR 1298A > C (AC or CC) were also insignificant when compared between the two groups. This is yet the largest case-control study conducted for MTHFR 677C > T and also the first to investigate a possible relation with MTHFR 1298A > C. The data presented in this study fail to support the relationship between MTHFR 677C > T and 1298A > C polymorphisms and risk of having a child with DS.     

Maternal gene polymorphisms involved in folate metabolism as risk factors for Down syndrome offspring in Southern Brazil

This study aimed to investigate the role of maternal polymorphisms, as well as their risk genotypes combinations of MTR A2756G, MTRR A66G, CBS 844ins68, and RFC A80G, involved in folate/homocysteine metabolism, as possible risk factors for Down syndrome (DS) in Southern Brazil. A case-control study was conducted with 239~mothers of DS children and 197~control mothers. The investigation of polymorphisms was performed by PCR and PCR-RFLP. The distribution of genotypic variants was similar in both groups when they were analyzed separately. An investigation of combined risk genotypes showed that the risk of having a DS child for one, two or three risk genotypes was 6.23, 6.96 and 5.84 (95%CI 1.48-26.26; 1.69-28.66; 1.37-24.86), respectively. The combined MTRR 66G and MTHFR 677T alleles were significantly more common among mothers of children with DS than among control mothers (OR 1.55; IC 95% 1.03-2.35). The results show that individual polymorphisms studied in this work are not associated with DS; however, the effects of the combined risk genotypes among MTR, MTRR, CBS and RFC genes are considered maternal risk factors for DS offspring in our population.     

Influence of advanced age of maternal grandmothers on Down syndrome

Background  

Down syndrome (DS) is the most common chromosomal anomaly associated with mental retardation. This is due to the occurrence of free trisomy 21 (92–95%), mosaic trisomy 21 (2–4%) and translocation (3–4%). Advanced maternal age is a well documented risk factor for maternal meiotic nondisjunction. In India three children with DS are born every hour and more DS children are given birth to by young age mothers than by advanced age mothers. Therefore, detailed analysis of the families with DS is needed to find out other possible causative factors for nondisjunction.     

唐氏综合征患儿线粒体基因组突变的分析

目的 研究唐氏综合征中线粒体DNA突变情况.方法 采用高通量测序和焦磷酸测序检测7个唐氏综合征(Down's syndrome,DS)家系中的患儿和母亲的线粒体基因组序列,分析线粒体基因组序列的变化情况.结果 ①DS患儿中检测到36个与其母亲中不同的线粒体DNA突变,其中14个位点是首次在唐氏综合征样本中发现;②36个线粒体DNA突变主要发生于D-Loop区和线粒体复合物Ⅰ中;③ 线粒体基因组13个编码基因中,有11个基因检测到线粒体DNA的突变;④ 焦磷酸测序对线粒体基因组杂合突变频率的检测结果和高通量测序结果吻合.结论 DS患儿中广泛存在线粒体DNA的突变,这些突变可能与唐氏综合征的线粒体功能异常相关.     

Relationship between polymorphisms in genes involved in homocysteine metabolism and maternal risk for Down syndrome in Brazil

Associations between specific alleles of genes encoding enzymes in the methionine/homocysteine pathway and plasma homocysteine levels have been examined in different populations. In the present study, we determined polymorphisms of MTHFR A222V (677C > T), MTHFR E429A (1298A > C), MTRR I22M (66A > G), MTR D919G (2756A > G), and CBS 844ins68 and total plasma homocysteine levels (tHcy) among 154 mothers of children with Down syndrome (DS) and 158 control mothers from Brazil. Homocysteine levels were higher among DS mothers compared to control groups (10.437 vs. 8.600 respectively, P = 0.002). Only the 677T allele was associated with altered levels of tHcy in the case group (F((2,153)) = 5.300; P = 0.006), primarily when homozygous. In the control group, the association of the TT genotype with higher levels of tHcy showed borderline significance (F((2,157)) = 2.974; P = 0.054). All genotype distributions were similar in the two groups (P > 0.05), but the frequency of the 677T allele in the case group was significantly higher (chi(2) = 3.862; DF = 1; P = 0.049; OR = 1.437 (1.001-2.062)). Although the 677T allele is associated with increased homocysteine levels, its presence has only a modest impact as an independent risk factor for DS. All the other polymorphisms did not show an association with risk for the syndrome, when evaluated separately (P > 0.05). However, when the presence of 677T, 1298C, 2756G, 66G, and 844ins68 alleles were evaluated together, the mothers of children with DS tend to have a higher number of uncommon alleles than the mothers with no previous affected child.     

MTHFR C677T and A1298C polymorphisms are risk factors for Down’s syndrome in Indian mothers

Downs syndrome (DS), a chromosomal disorder due to trisomy 21, results mostly from nondisjunction in maternal meiosis. The present case-control study examined the association of genetic polymorphisms with predisposition to nondisjunction. Two common polymorphisms (SNPs), C677T and A1298C, in the 5,10-methylenetetrahydrofolate reductase (MTHFR) gene involved in folate metabolism, are known to lower the activity of this enzyme. Three hundred and fourteen mothers (with DS children and controls), mostly from the eastern states of India, were genotyped for the two above-mentioned SNPs. Significant association with both of these SNPs were detected, more specifically, in the mothers of DS children homozygous for the polymorphic alleles 677 T and 1298 C. The relative risk of T (C677T) and C (A1298C) homozygosity in mothers for DS-affected pregnancy was 7 (OR 7.67, 95% CI 1.67–35.08, P=0.003) and 4 (OR 4.40, 95% CI 1.45–13.26, P=0.008), respectively. Moreover, all 677TT mothers studied were less than 31 years of age, whereas no correlation with maternal age was observed for A1298C genotypes. Interestingly, all of the young 677TT mothers had either a first- or secondborn child with DS. Thus, this study reports that young Indian mothers with TT genotypes are genetically predisposed to nondisjunction due to abnormal folate metabolism.     

Maternal polymorphisms 677C-T and 1298A-C of MTHFR, and 66A-G MTRR genes: is there any relationship between polymorphisms of the folate pathway, maternal homocysteine levels, and the risk for having a child with Down syndrome?

This study was aimed at analyzing the effect of mutations in three non-synonymous SNP genes (677C > T and 1298A > C of the methylenetetrahydrofolate reductase (MTHFR) gene, and 66A > G in the MTRR gene) on total plasmatic homocysteine (Hcy), in 91 mothers of Down syndrome (DS) infants and 90 control mothers. The comparison of both groups of mothers is a new way to determine if those mutations and their interactions increase the risk for DS. Material came from the case-control network of the Spanish Collaborative Study of Congenital Malformations (ECEMC). Using a general lineal model in a backwards step, we performed the analyses including the different mutations, maternal age, the fact that each mother had a DS or a control infant, and all possible interactions of these variables, in the models, being maternal Hcy the continuous dependent variable. In another model, maternal folic acid intake during the third trimester of pregnancy was added. The results from both models were essentially the same: Hcy levels variability differs from case mothers to control ones, the presence of the MTHFR1298A > C polymorphism also affects significantly the Hcy variance, as it does the statistical interaction between the mutations MTRR66A > G and MTHFR1298A > C in the mother. In this sense, the interaction between different polymorphisms may totally modify their individual effects, and some of those effects are different in mothers of DS children and in controls' mothers. For instance, only two mutations in MTRR66 (GGAA) in mothers of control infants increase the reference maternal Hcy level in 4.66 units, and the individual effect of the genotype with only two mutations in the MTHFR1298 gene (AACC) increases the reference Hcy level in 12.74 units. However, the presence of the four mutations (GGCC) interacts giving a statistically significant decrease in 6.00 units in the level of Hcy in control mothers. On the contrary, in mothers of DS infants, the sole presence of two mutations in one of these two genes decreases the levels of Hcy (-2.31 units for GGAA genotype, and -3.43 units for AACC genotype), while the presence of the four mutations (GGCC) increases Hcy in 9.53 units. Taking into consideration that in the one-carbon metabolism cystathionine beta-synthase (CBS) catalyzes Hcy in an irreversible way, and that CBS gene is located in chromosome 21, fetuses and infants with DS have functional folate deficiency due to overexpression of CBS. This fact, as well as others influencing Hcy levels (such as nutrients interactions and lifestyle), together with the fetal genotype, suggest that their relationship with DS could be through an effect on fetal survival up to birth. Three possible mechanisms are considered by evaluating the results in the light of the present knowledge on cytology and molecular biology.     

Maternal age and Down syndrome: age-specific incidence rates by single-year intervals.

Maternal age-specific risks of giving birth to a child with the Down syndrome (DS) are given by single-year age intervals. Such data are of value for more precise genetic counseling and in cost-benefit analyses of prenatal diagnosis programs. The data were obtained by linking records of children with DS at the British Columbia Health Surveillance Registry ( BCHSR ) to the appropriate birth registrations to derive maternal ages. The data related to 519 affected children out of a total of 354,880 live births in British Columbia between 1961 and 1970. The results, which are based on a high level of ascertainment, are compared to those reported in the only other published study relating to risks by single-year maternal age groupings, where completeness of ascertainment was estimated to be only 38%.     

Attitudes towards Down''s syndrome: follow up of a cohort of 280 cases.

A follow up study of a cohort of 280 Down's syndrome (DS) fetuses was initiated in order to estimate the percentage of terminations of pregnancy, the prevalence at birth, the survival of DS children, the attitude of the parents at birth, and the medical and surgical care provided. The present study is a preliminary analysis of the data collected up to the age of 1 year. It shows that 43% of the 280 DS fetuses had died by the end of the first year of life, owing to termination of pregnancy (27%), late spontaneous abortion or stillbirth (4%), or death during the first year of life (12%). Among the 33 children who died, 12 had a common atrioventricular canal, six had another major malformation, three died from infection, one from respiratory distress, two were cot deaths, and one was an infanticide, but eight deaths were unexplained, occurring in children with no known malformation or disease. Among the 185 children still alive after 2 days, 23 (12%) were available for adoption, their mothers having elected to remain anonymous. These results show that in some instances parents or professionals feel justified on one hand in not providing DS children with the necessary care and on the other hand to transfer their responsibilities to the public health system. The influence of prenatal diagnosis of chromosome disorders as a determining factor of the social acceptance of DS is still questionable.     

MTHFR genetic polymorphism as a risk factor in Egyptian mothers with Down syndrome children

Recent reports linking Down syndrome (DS) to maternal polymorphisms at the methylenetetrahydrofolate reductase (MTHFR) gene locus have generated great interest among investigators in the field. The present study aimed at evaluation of MTHFR 677C/T and 1298A/C polymorphisms in the MTHFR gene as maternal risk factors for DS. Forty two mothers of proven DS outcomes and forty eight control mothers with normal offspring were included. Complete medical and nutritional histories for all mothers were taken with special emphasis on folate intake. Folic acid intake from food or vitamin supplements was significantly low (below the Recommended Daily Allowance) in the group of case mothers compared to control mothers. Frequencies of MTHFR 677T and MTHFR 1298C alleles were significantly higher among case mothers (32.1% and 57.1%, respectively) compared to control mothers (18.7% and 32.3%, respectively). Heterozygous and homozygous genotype frequencies of MTHFR at position 677 (CT and TT) were higher among case mothers than controls (40.5% versus 25% and 11.9% versus 6.2%, respectively) with an odds ratio of 2.34 (95% confidence interval [CI] 0.93-5.89) and 2.75 (95% CI 0.95-12.77), respectively. Interestingly, the homozygous genotype frequency (CC) at position 1298 was significantly higher in case mothers than in controls (33.3% versus 2.1% respectively) with an odds ratio of 31.5 (95% CI 3.51 to 282.33) indicating that this polymorphism may have more genetic impact than 677 polymorphism. Heterozygous genotype (AC) did not show significant difference between the two groups. We here report on the first pilot study of the possible genetic association between DS and MTHFR 1298A/C genotypes among Egyptians. Further extended studies are recommended to confirm the present work.     

Maternal age and down syndrome: Age-specific incidence rates by single-year intervals

Maternal age-specific risks of giving birth to a child with the Down syndrome (DS) are given by single-year age intervals. Such data are of value for more precise genetic counseling and in cost-benefit analyses of prenatal diagnosis programs. The data were obtained by linking records of children with DS at the British Columbia Health Surveillance Registry (BCHSR) to the appropriate birth registrations to derive maternal ages. The data related to 519 affected children out of a total of 354,880 live births in British Columbia between 1961 and 1970. The results, which are based on a high level of ascertainment, are compared to those reported in the only other published study relating to risks by single-year maternal age groupings, where completeness of ascertainment was estimated to be only 38%.     

The biochemical structure and function of methylenetetrahydrofolate reductase provide the rationale to interpret the epidemiological results on the risk for infants with Down syndrome

Studies on the structure of the methylenetetrahydrofolate reductase (MTHFR) gene and the mechanisms by which folate may reduce homocysteine levels in bacteria and in humans have provided a rationale to understand the conflicting epidemiological observations between the studies on the 677C-T and 1298A-C MTHFR polymorphic variants, and the risk of having an infant with Down syndrome (DS). However, three of the combined genotypes (CTCC, TTAC, and TTCC) are very infrequent in the human population. In fact, these three rare genotypes were only observed in two of the eight epidemiological studies that analyzed these genotype combinations and the risk of DS. In a study of the Indian population these three genotypes were identified in mothers of DS children but not in control mothers demonstrating a statistically significant increase in the risk of giving birth to DS infants. Conversely, the CTCC and TTAC genotypes were only observed in control mothers and not in mothers of DS infants in the Spanish study, while the TTCC genotype was not observed in any Spanish mother analyzed. These results were not related to the frequency of the T allele, since this was lower in the Indian population (21.4% among case mothers and 12.4% in control mothers) than in the Spanish population (33.9%). At present, several important biological aspects on the Hcy cycle are known, including: (a) the biochemical structure and function of the MTHFR enzyme, (b) the biological basis for the effect of the different 677C-T and 1298A-C MTHFR genotype combinations on Hcy levels, (c) that folate is not synthesized by the organism that obtained it from the diet, (d) that TT homozygotes will be at particular risk when their folate status is low because the mutant enzyme requires much higher levels of folate than the physiological one to stabilize the binding of flavin-adenosine-dinucleotide (FAD), (e) that the release of flavin is prevented by increasing the levels of folate, and (f) that the cystathionine-beta-synthase gene is located on chromosome 21. Together, these facts suggest that destabilization of the Hcy cycle in function of the levels of S-adenosylmethionine (SAM), may be modified by some embryonic and maternal genotypes, as well as by maternal nutritional status and life style. This may also influence the probability that some embryos survive to birth, but in different way for those with and without trisomy 21, as is discussed in this article.     

Parental α 1-antitrypsin (PI) types and meiotic nondisjunction in the aetiology of Down syndrome

In 100 children with Down syndrome (DS), the parental origin of the supernumery chromosome 21 was investigated. In 76 out of the 100 cases the polymorphic regions were informative, i.e. the nondisjunction could be traced. Assessment of the alpha 1-antitrypsin/alpha 1-protease inhibitor (PI) types in these DS children revealed a significantly higher value of non-M PI variants (P less than 0.05). In their fathers the non-M PI variants were not increased, not even in those in whom nondisjunction had taken place. A clearly significantly higher value (P less than 0.001) of non-M PI variants was found in their mothers, particularly when only the MS and MZ types which are recognised as deficiency variants were considered. Most striking, however, is the almost 5-fold increased frequency of MS and MZ types found in mothers where the nondisjunction had occurred during the first meiotic division. This would suggest that PI deficiency interferes with some process leading to non-disjunction. If these findings are confirmed, application of Bayes' theorem enables us to estimate the risk for MZ and MS heterozygous women to have a DS child: this would be 3- to 4- fold higher than for MM homozygous women. This would be of interest for genetic counselling and enhance the benefits of prenatal diagnosis programmes.     

Breast milk fatty acids and allergic disease in preschool children: the Prevention and Incidence of Asthma and Mite Allergy birth cohort study

BACKGROUND: Better understanding of the association between early life lipid intakes and the development of allergic diseases is needed. OBJECTIVE: We prospectively studied breast milk content of n-6, n-3, and trans fatty acids in relation to allergic symptoms at the ages of 1 and 4 years. METHODS: Fatty acid content was determined in breast milk samples of 265 (158 allergic and 107 nonallergic) mothers of children participating in the Prevention and Incidence of Asthma and Mite Allergy study. Outcome variables studied were parental reported eczema at age 1 year, eczema at age 4 years, asthma at age 4 years, and, in a subgroup of 133 children, sensitization at age 4 years. RESULTS: In children of mothers with allergy, breast milk n-3 long chain polyunsaturated fatty acids and the ratio between n-3 and n-6 long chain polyunsaturated fatty acids were inversely associated with asthma and with persistent symptoms (eczema at age 1 year and eczema at age 4 years and/or asthma at age 4 years), but no associations between breast milk fatty acids and sensitization were observed. In children of mothers with allergy, also trans fatty acids tended to be inversely associated with allergic symptoms. In children of mothers without allergy, no associations between breast milk fatty acids and allergic symptoms were observed, but alpha-linolenic acid (18:3n-3) was positively associated with sensitization. CONCLUSION: In susceptible infants, the risk to develop allergic symptoms, but not the risk of sensitization, was modified by intake of n-3 long chain polyunsaturated fatty acids through breast milk.     

Higher risk of hepatitis C virus perinatal transmission from drug user mothers is mediated by peripheral blood mononuclear cell infection

Maternal injection drug use and peripheral blood mononuclear cell infection by hepatitis C virus are important risk factors for perinatal transmission of the virus. The aim of present study was to evaluate the independent association of these two factors on perinatal transmission. Forty-eight consecutive mothers who transmitted infection to their offspring and 122 consecutive mothers who did not, together with their children, were examined. Both maternal injection drug use and peripheral blood mononuclear cell infection were significantly more frequent in infected than in uninfected children (respectively P = 0.04; odds ratio 2.33, 95% confidence intervals 1.02-5.42 and P < 10(-6); odds ratio and 95% confidence intervals not calculable due to zero values). Multivariate analysis confirmed the link between maternal peripheral blood mononuclear cell infection and perinatal transmission (P < 10(-6); odds ratio and 95% confidence intervals not calculable due to zero values) but no association was found with maternal injection drug use. The high risk of perinatal transmission found in injection drug use mothers is dependent on maternal peripheral blood mononuclear cell infection by hepatitis C virus. Peripheral blood mononuclear cell infection represents one of the most important risk factors for hepatitis C virus perinatal transmission.     

Functional Inference of Methylenetetrahydrofolate Reductase Gene Polymorphisms on Enzyme Stability as a Potential Risk Factor for Down Syndrome in Croatia

Understanding the biochemical structure and function of the methylenetetrahydrofolate reductase gene (MTHFR) provides new evidence in elucidating the risk of having a child with Down syndrome (DS) in association with two common MTHFR polymorphisms, C677T and A1298C. The aim of this study was to evaluate the risk for DS according to the presence of MTHFR C677T and A1298C polymorphisms as well as the stability of the enzyme configuration. This study included mothers from Croatia with a liveborn DS child (n = 102) or DS pregnancy (n = 9) and mothers with a healthy child (n = 141). MTHFR C677T and A1298C polymorphisms were assessed by PCR-RFLP. Allele/genotype frequencies differences were determined using χ² test. Odds ratio and the 95% confidence intervals were calculated to evaluate the effects of different alleles/genotypes. No statistically significant differences were found between the frequencies of allele/genotype or genotype combinations of the MTHFR C677T and A1298C polymorphisms in the case and the control groups. Additionally, the observed frequencies of the stable (677CC/1298AA, 677CC/1298AC, 677CC/1298CC) and unstable (677CT/1298AA, 677CT/1298AC, 677TT/1298AA) enzyme configurations were not significantly different. We found no evidence to support the possibility that MTHFR polymorphisms and the stability of the enzyme configurations were associated with risk of having a child with DS in Croatian population.     

Medical,welfare, and educational challenges and psychological distress in parents caring for an individual with 22q11.2 deletion syndrome: A cross-sectional survey in Japan

Parents of children with 22q11.2 deletion syndrome (22q11DS) experience distress not only due to multimorbidity in the patients, but also due to professionals' lack of understanding about 22q11DS and insufficient support systems. This study investigated relationships between medical, welfare, and educational challenges and parental psychological distress. A cross-sectional survey was conducted on primary caregivers of children with 22q11DS. Participants included 125 parents (114 mothers, 91.2%; average age = 44.3 years) who reported their challenges, psychological distress, and child's comorbidities of 22q11DS. Results showed that the difficulty in going to multiple medical institutions (β = 0.181, p < 0.05) and lack of understanding by welfare staff and insufficient welfare support systems for 22q11DS (β = 0.220–0.316, all p < 0.05) were associated with parental psychological distress, even after adjusting for child's comorbidities. In the subsample of parents whose child attended an educational institution, inadequate management in classroom and mismatch between service and users in educational settings were associated with psychological distress (β = 0.222–0.296, all p < 0.05). This study reveals the importance of assessing not only severity of comorbidities in 22q11DS, but also the medical, welfare, and educational challenges for parental mental health.     

Dextrin sulfate as a vaginal microbicide: randomized,double-blind,placebo-controlled trial including healthy female volunteers and their male partners

This randomized, placebo-controlled trial assessed the safety and acceptability of vaginally administered 0.125% dextrin sulfate (DS) gel in sexually active women and their male partners. A single 2-mL dose of study gel was self-administered every night over two 14-day periods separated by a 7-day interval, during which menses was expected to occur. Up to two supplementary doses per 24 hours were provided for use before sexual intercourse. Semistructured interview, colposcopy, and laboratory safety studies were used to assess adverse events. Male partners who agreed to participate in a substudy were exposed to gel through sexual intercourse during the second 14-day exposure period. Seventy-three women (36 DS recipients and 37 placebo recipients) used at least one application of gel, of whom 66 (33 DS recipients and 33 placebo recipients) completed follow-up. Eleven women (5 DS recipients and 6 placebo recipients) reported intermenstrual bleeding during gel use, which in most cases was light and resolved within 24 hours. Ten male partners (4 with DS exposure and 6 with placebo exposure) were enrolled in the study and all completed follow-up. There was no evidence of systemic toxicity or genital epithelial disruption attributable to DS gel.