Anogenital Distance In Infants Research Articles

Longitudinal evaluation of fetal and infant AGD in healthy children: association with penile size, testosterone and DHT.

The anogenital distance (AGD) is considered a postnatal readout of early fetal androgen action. Little is known of prenatal AGD and how it correlates with AGD postnatally. We present longitudinal measurements of fetal- and infant AGD. We evaluate the impact of testosterone and dihydrotestosterone at minipuberty on AGD and penile size. Secondary analyses of an observational, prospective pregnancy and birth cohort, COPANA (2020-2022). Copenhagen University Hospital - Rigshospitalet. 685 healthy, singleton pregnant women enrolled, 657 women attended 3rd trimester ultrasound, 589 infants completed follow-up. 3rd trimester ultrasound (GW29-34): Fetal AGD. Minipuberty clinical examination (app. 3.5 months postpartum): infant AGD, penile width and stretched length (SPL), circulating testosterone and dihydrotestosterone (LC-MS/MS). AGD was available in 650/657 fetuses (310 boys) and 588/589 infants (287 boys). Boys had longer fetal and infant AGD compared to girls; fetal AGDas: mean (SD) 21.4 mm (±3.5), fetal AGDaf: 12.8 mm (±2.3), p < 0.001, infant AGDas: 32.0 mm (±5.6) and infant AGDaf: 15.8 (±3.3), p < 0.001. Fetal AGD correlated with infant AGD in boys and girls (Spearman's r = 0.275, p < 0.001 and r = 0.189, p = 0.001 respectively), but not with circulating testosterone or dihydrotestosterone at minipuberty. Penile size correlated positively with circulating androgen levels at minipuberty, i.e.: SPL vs testosterone: r = 0.235, p < 0.001. AGD is sexual dimorphic already in the 3rd trimester. Fetal and infant AGD correlates. AGD is associated with body size but not circulating androgen levels at minipuberty. These findings suggest that fetal and infant AGD, reflect androgen action during early fetal development.

Endocrine disrupting chemicals and their effects on the reproductive health in men

Endocrine Disrupting Chemicals (EDCs) are harmful compounds that enter the environment naturally or through anthropogenic activities and disrupt normal endocrine functions in humans, adversely affecting reproductive health. Among the most significant sources of EDC contaminants are the pharmaceutical, cosmetic, and packaging industries. EDCs have been identified to have a deteriorating effect on male reproductive system, as evidenced by the increasing number of male infertility cases. A large number of case studies have been published in which men exposed to EDCs experienced testicular cancer, undescended testicles, a decrease in serum testosterone levels, and poor semen quality. Furthermore, epidemiological evidence suggested a link between prenatal EDC exposure and cryptorchidism or undescended testicles, hypospadias, and decreased anogenital distance in infants. The majority of these findings, however, are incongruent due to the lack of long-term follow-up studies that would demonstrate EDCs to be associated with male reproductive disorders. This review aims to provide an overview on recent scientific progress on the association of EDCs to male reproductive health with special emphasis on its toxicity and possible mechanism of EDCs that disrupt male reproductive system.

Associations between maternal urinary isoflavone concentrations and anogenital distance of offspring throughout infancy: a prospective cohort study.

Are maternal urinary isoflavone (ISO) concentrations during pregnancy associated with anogenital distance (AGD) in infants at birth, and at 6 and 12 months of age? Higher maternal urinary ISO concentrations during pregnancy were associated with longer AGD in infants of both sexes, and equol (EQU) and daidzein (DAD) were identified as the important ISO mixture components in the observed associations. Evidence of the association of prenatal exposure to ISO with offspring's AGD is mainly derived from animal studies, which used different study designs and had inconsistent results. Only one human study has been reported and it found null associations between maternal ISO exposure during pregnancy and AGD among boys at birth, with a small sample size and a wide range of exposure windows. No human study on girls was found. Prospective cohort study (Shanghai-Minhang Birth Cohort Study), with pregnant women recruited at 12-16 weeks of gestation in Shanghai, China between April and December 2012. One thousand two hundred and twenty-five live singletons were left in the cohort at delivery of which 480 mother-infant pairs had data on both maternal urinary ISO concentrations and at least one AGD measurement and were included in the present study. Anopenile distance (AGDAP) and anoscrotal distance (AGDAS) of boys and anoclitoral distance (AGDAC) and anofourchette distance (AGDAF) of girls were measured at birth and at 6 and 12 months of age. Multiple linear regression models were used to examine the associations between maternal ISO concentrations and AGD. Bayesian kernel machine regression (BKMR) was implemented to examine both the overall effects of ISO mixture and the single effect of each ISO and identify important components of ISO mixture. A general profile of higher concentrations of maternal ISO associated with longer AGD in infants of both sexes was observed, when maternal education, parity, BMI before pregnancy (BMI, categorical variable), passive smoking during early pregnancy, age at delivery, gestational weeks and infant body size were adjusted for. Among boys, EQU was associated with increased AGDAS at birth and at 6 and 12 months, and DAD was associated with increased AGDAP at birth. Among girls, the associations of EQU and DAD with increased AGDAC and AGDAF at birth were found. When gestational weight gain and feeding patterns of infants in the first 6 months were additionally adjusted for, and maternal BMI was adjusted for as a continuous variable, more pronounced associations were observed, especially for associations of genistein (GEN), DAD and glycitein (GLY) with increased AGDAP and AGDAS at 6 months in boys. However, these associations were not always observed in the highest tertile group, and no consistent dose-response relationships were found. Similar results were observed in BKMR models, showing positive correlations of concentration of ISO mixture with increased AGDAS at both 6 and 12 months among boys, and increased AGDAC and AGDAF at birth among girls. Statistically significant increments of 4.96 mm (95% credible interval (CrI): 1.40, 8.52) and 1.07 mm (95% CrI: 0.02, 2.13) in AGDAS at 6 months among boys and AGDAC at birth among girls, respectively, were observed at the 75th percentile of ISO mixture, compared with 25th percentile. EQU and DAD were identified as the important components among ISO-AGD associations. First, due to the short half-lives of ISO, the accuracy of a single spot urine sample reflecting ISO exposure during pregnancy may be limited, and thus may cause non-differential misclassification. Second, despite the adjustments for several important covariates in the study, unmeasured and residual confounding factors may remain a concern. Third, false discovery due to multiple testing may remain. Finally, the reduced sample sizes attributed to the loss of follow-up and missing data of confounders may limit our ability to detect an association, if any existed. Prenatal ISO exposure may affect the reproductive development of offspring. As ISO can be widely detected in pregnant women, especially in Eastern countries, more studies are warranted to provide evidence of the effects of prenatal ISO exposure on long-term reproductive outcomes. This work was supported by grants from the National Key Research and Development Program of China (2021YFC2701003), the National Natural Science Foundation of China (22076123), the Science and Technology Commission of Shanghai Municipality (21ZR1454700 and 20ZR1448000), the Shanghai Municipal Health Commission (20194Y0160) and Innovation-oriented Science and Technology Grant from NHC Key Laboratory of Reproduction Regulation (CX2022-04). The authors have no conflicts of interest to declare. N/A.

Prenatal exposure to residential PM2.5 and anogenital distance in infants at birth: A birth cohort study from Shanghai, China

Fine particulate matter (PM2.5) is believed to be one of the most hazardous air pollution with a ubiquitous presence. Animal studies have reported the association between prenatal exposure to traffic pollutant (not exclusively including PM2.5) and reproductive development in male offspring. However, the effects of prenatal exposure to PM2.5 on reproductive health in children are still unknown. The present study was based on the Shanghai-Minhang Birth Cohort Study (S-MBCS). A total of 876 pregnant women and their infants were included. Infants’ anogenital distance (AGD, the distance from the anus to the genitals; AGDap [anus-penis] and AGDas [anus-scrotum] for boys, and AGDac [anus-clitoris] and AGDaf [anus-fourchette] for girls) were measured at birth. PM2.5 concentrations during pregnancy were estimated using satellite based modeling approach. Multiple linear regression analysis and multiple informant model were conducted to examine the associations between prenatal exposure to PM2.5 (pre μg/m3) and offspring’s AGDs (mm). In order to minimize the misclassification of exposure, a sensitivity analysis restricted to mothers being off work during pregnancy was performed. In multiple linear regression models, we found that prenatal exposure to PM2.5 during the 1st and 3rd trimesters was associated with shorter AGDs. In multiple informant model, similar patterns were found, and statistically significant reductions were observed in AGDap (β=−0.278, 95%CI: -0.343∼-0.212), AGDac (β=−0.188, 95%CI: -0.247∼-0.130) and AGDaf (β= −0.163, 95%CI: -0.238∼-0.088) with PM2.5 exposure during the 1st trimester, and AGDap (β=−0.201, 95%CI: -0.247∼-0.155), AGDas (β=−0.158, 95%CI: -0.198∼-0.117), AGDac (β=−0.128, 95%CI: -0.167∼-0.089) and AGDaf (β = −0.144, 95%CI: -0.194∼-0.094) with PM2.5 exposure during the 3rd trimester. The sensitivity analysis restricted to women being off work during pregnancy showed similar results. PM2.5 exposure during the 1st and 3rd trimesters was associated with shortened AGDs in offspring at birth. Our findings provide preliminary evidence that prenatal exposure to PM2.5 might be associated with the reproductive development of offspring.

Association between Anogenital Distance and External Genital Anomalies in Nigerian Newborn Infants

Aim: Animal studies regarding endocrine dysfunction have linked anomalies of male external genitalia with reduced anogenital distance (AGD). Human studies have associated shorter AGD with genital anomalies in males. The aim of the present study is to report the AGD measurement among Nigerian newborn infants with undescended testis and/or hypospadias and compare the results with that of infants with normal external genitalia. Methods: In this case-control study, the AGD of 17 newborn infants with abnormal external genitalia (undescended testis (UDT)/hypospadias) was measured and the result compared with that of 34 newborn infants with normal external genitalia (descended testes and no hypospadias, epispadias or chordee). Each case recruited was matched for birth weight and length with two controls delivered consecutively. Thus, a total of 51 (cases and controls) newborn infants were ultimately studied. The differences in AGD between infants with abnormal external genitalia compared with that of infants with normal external genitalia were examined, using two-tailed Student’s t-test, with p-value set at &lt; 0.05. In addition, the AGD in infants with hypospadias was compared with the AGD in infants with UDT. Results: The mean AGD was 27.6±4.9mm (95% CI = 26.0-29.2), 26.3±5.4mm (95% CI = 23.0-29.6) and 25.1±6.2 mm (95 CI = 20.1-30.1) in infants with normal external genitalia, UDT and hypospadias, respectively; p &gt; 0.05. The mean AGD was shorter in infants with hypospadias compared with infants with UDT, p &gt; 0.05. Conclusions: The AGD in Nigerian newborn infants with either UDT or hypospadias tended to be shorter than that of their counterparts with normal genitals and this reduction was more in infants with hypospadias compared with infants with UDT.

Prenatal exposure to persistent organic compounds and their association with anogenital distance in infants.

What is the association between prenatal exposure to persistent organic pollutants, separately and combined, and anogenital distance (in-utero endocrine disruption marker). A cohort study conducted in Sonora, Mexico. Blood concentrations of polychlorobiphenyls (PCB) 28, 74, 118, 138/158, 153, 170, 180 and the isomers of dichlorodiphenyltrichloroethane (DDT) and its metabolites were determined in women in the third trimester of pregnancy; three variants of anogenital distance were measured on five occasions during the first year of life of their infants: 82 girls (402 observations) and 74 boys (356 observations). Boys had negative and significant associations between anogenital distance/height and the concentrations of PCB 28 (beta = - 0.005;P = 0.006), PCB 74 (beta = - 0.003;P = 0.013), and PCB 170 (beta = - 0.005;P = 0.001) when analysed individually. Negative and significant associations were also found using statistical models applied to mixtures of compounds. The latter associations were sometimes larger in magnitude and significance, suggesting a possible potentiation of the compounds. No associations were observed between anogenital distance and DDT in either sex or with PCB in girls. The decreased anogenital distance associated with prenatal exposure to the persistent organic pollutants, observed consistently in different analyses, suggests an under-masculinizing effect of these environmental pollutants in boys.

Prenatal Exposure to Phthalates and Phenols and Infant Anogenital Distance

Measurement of endocrine sensitive endpoints, especially those that are sexually dimorphic, such as anogenital distance (AGD), can be used as sentinels for later adverse health effects arising from prenatal exposure to endocrine disrupting chemicals. Some studies have reported reduced AGD in male infants with increasing maternal urinary phthalate concentrations; one study reported an association in female infants, while others report no significant associations. Human studies of phenols and AGD are sparse.Phthalate and phenol concentrations were measured in 1st trimester urines in the pan-Canadian MIREC Study. After birth, short and long measures of AGD were conducted in 197 male and 195 female infants. Multiple linear regression models were created to examine the relationship between the AGD and the exposure of interest, including specific gravity and significant confounders as identified from the change-in estimate procedure. The same confounders were kept for all phenol and phthalate models.The anus-clitoris distance was negatively associated with the phthalate metabolite MBzP (&amp;#946; &amp;#61; -1.24; 95% CI -1.91, -0.57) and positively associated with MEP (&amp;#946; &amp;#61; 0.65; 95% CI 0.12, 1.18). The anopenile distance was positively associated with MnBP (&amp;#946; &amp;#61; 1.17; 95% CI 0.02, 2.32) and the molar sum of low molecular weight phthalates (&amp;#931;LMW) (&amp;#946; &amp;#61; 1.10; 95% CI 0.13, 2.08). No significant associations were observed between prenatal BPA or triclosan urinary concentrations and AGD in either sex.Given the large number of associations examined, the statistical associations observed may have been due to Type 1 error. The inconsistency in results between studies of prenatal phthalate exposure suggests that this issue is yet to be resolved.

First-Trimester Urinary Bisphenol A Concentration in Relation to Anogenital Distance, an Androgen-Sensitive Measure of Reproductive Development, in Infant Girls.

Introduction:Evidence from animal models suggests that prenatal exposure to bisphenol A (BPA), a ubiquitous endocrine-disrupting chemical, is associated with adverse reproductive outcomes in females. Exposure during early gestation, a critical period for reproductive development, is of particular concern. Anogenital distance (AGD) is a sensitive biomarker of the fetal hormonal milieu and a measure of reproductive toxicity in animal models. In some studies, the daughters of BPA-exposed dams have shorter AGD than controls. Here, we investigate this relationship in humans.Methods:BPA was assayed in first-trimester urine samples from 385 participants who delivered infant girls in a multicenter pregnancy cohort study. After birth, daughters underwent exams that included two measures of AGD (AGD-AC: distance from center of anus to clitoris; AGD-AF: distance from center of anus to fourchette). We fit linear regression models to examine the association between specific gravity–adjusted (SPG-adj) maternal BPA concentrations and infant AGD, adjusting for covariates.Results:BPA was detectable in 94% of women. In covariate-adjusted models fit on 381 eligible subjects, the natural logarithm of SpG-adj maternal BPA concentration was inversely associated with infant AGD-AC [, 95% confidence interval (CI): , ]. We observed no association between maternal BPA and infant AGD-AF.Conclusion:BPA may have toxic effects on the female reproductive system in humans, as it does in animal models. Higher first-trimester BPA exposure was associated with significantly shorter AGD in daughters, suggesting that BPA may alter the hormonal environment of the female fetus. https://doi.org/10.1289/EHP875

Prenatal paracetamol exposure is associated with shorter anogenital distance in male infants

STUDY QUESTIONWhat is the relationship between maternal paracetamol intake during the masculinisation programming window (MPW, 8–14 weeks of gestation) and male infant anogenital distance (AGD), a biomarker for androgen action during the MPW?SUMMARY ANSWERIntrauterine paracetamol exposure during 8–14 weeks of gestation is associated with shorter AGD from birth to 24 months of age.WHAT IS ALREADY KNOWNThe increasing prevalence of male reproductive disorders may reflect environmental influences on foetal testicular development during the MPW. Animal and human xenograft studies have demonstrated that paracetamol reduces foetal testicular testosterone production, consistent with reported epidemiological associations between prenatal paracetamol exposure and cryptorchidism.STUDY DESIGN, SIZE, DURATIONProspective cohort study (Cambridge Baby Growth Study), with recruitment of pregnant women at ~12 post-menstrual weeks of gestation from a single UK maternity unit between 2001 and 2009, and 24 months of infant follow-up. Of 2229 recruited women, 1640 continued with the infancy study after delivery, of whom 676 delivered male infants and completed a medicine consumption questionnaire.PARTICIPANTS/MATERIALS, SETTING, METHODMothers self-reported medicine consumption during pregnancy by a questionnaire administered during the perinatal period. Infant AGD (measured from 2006 onwards), penile length and testicular descent were assessed at 0, 3, 12, 18 and 24 months of age, and age-specific Z scores were calculated. Associations between paracetamol intake during three gestational periods (<8 weeks, 8–14 weeks and >14 weeks) and these outcomes were tested by linear mixed models. Two hundred and twenty-five (33%) of six hundred and eighty-one male infants were exposed to paracetamol during pregnancy, of whom sixty-eight were reported to be exposed during 8–14 weeks. AGD measurements were available for 434 male infants.MAIN RESULTS AND THE ROLE OF CHANCEParacetamol exposure during 8–14 weeks of gestation, but not any other period, was associated with shorter AGD (by 0.27 SD, 95% CI 0.06–0.48, P = 0.014) from birth to 24 months of age. This reduction was independent of body size. Paracetamol exposure was not related to penile length or testicular descent.LIMITATIONS, REASONS FOR CAUTIONConfounding by other drugs or endocrine-disrupting chemicals cannot be discounted. The cohort was not fully representative of pregnant women in the UK, particularly in terms of maternal ethnicity and smoking prevalence. There is likely to have been misclassification of paracetamol exposure due to recall error.WIDER IMPLICATIONS OF THE FINDINGSOur observational findings support experimental evidence that intrauterine paracetamol exposure during the MPW may adversely affect male reproductive development.STUDY FUNDING/COMPETING INTERESTSThis work was supported by a European Union Framework V programme, the World Cancer Research Fund International, the Medical Research Council (UK), the Newlife Foundation for Disabled Children, the Evelyn Trust, the Mothercare Group Foundation, Mead Johnson Nutrition, and the National Institute for Health Research Cambridge Comprehensive Biomedical Research Centre. The authors declare no conflict of interest.

Prenatal Stress as a Modifier of Associations between Phthalate Exposure and Reproductive Development: results from a Multicentre Pregnancy Cohort Study.

Prenatal phthalate exposure is associated with altered male reproductive tract development, and in particular, shorter anogenital distance (AGD). AGD, a sexually dimorphic index of prenatal androgen exposure, may also be altered by prenatal stress. How these exposures interact to impact AGD is unknown. Here, we examine the extent to which associations between prenatal phthalate exposure and infant AGD are modified by prenatal exposure to stressful life events (SLEs). Phthalate metabolites [including those of diethylhexyl phthalate (DEHP) and their molar sum (ΣDEHP)] were measured in first trimester urine from 738 pregnant women participating in The Infant Development and the Environment Study (TIDES). Women completed questionnaires on SLEs, and permitted infant AGD measurements at birth. Subjects were classified as 'lower' and 'higher' stress (0 first trimester SLEs vs. 1+).We estimated relationships between phthalate concentrations and AGD (by infant sex and stress group) using adjusted multiple regression interaction models. In the lower stress group, first trimester ΣDEHP was inversely associated with two measures of male AGD: anoscrotal distance (AGD-AS; β = -1.78; 95% CI -2.97, -0.59) and anopenile distance (AGD-AP; β = -1.61; 95% CI -3.01, -0.22). By contrast, associations in the higher stress group were mostly positive and non-significant in male infants. No associations were observed in girls. Associations between prenatal phthalate exposure and altered genital development were only apparent in sons of mothers who reported no SLEs during pregnancy. Prenatal stress and phthalates may interact to shape fetal development in ways that have not been previously explored.

Shorter anogenital distance correlates with undescended testis: a detailed genital anthropometric analysis in human newborns

Are the anogenital distance (AGD) and stretched penile length (SPL) shorter in human newborn males with cryptorchidism? AGD is significantly shorter in boys with undescended testis (UDT) and this correlation may indicate that both have a common antecedent early in gestation. Animal studies have reported a critical time period during early gestation termed the male programming window (MPW) where androgen deficiency results in reduced AGD and penile length, as well as cryptorchidism and hypospadias. Two pilot human studies have explored this association but these studies were small and heterogeneous with regard to age, race and had selection bias. A prospective descriptive study involving measurement of AGD and SPL at birth in a racially homogenous sample of 1154 consecutive newborns was performed over a period of 6 months. All measurements were taken by a single trained observer (V.J.). All consecutively born male infants at a community hospital were classified as having descended and or UDT. Testicular position in the undescended group was graded as high scrotal, inguinal or non-palpable. AGD (from the centre of anus to the junction of the smooth and rugated skin of scrotum) and SPL were measured. The AGD index (AGDi) was calculated by dividing AGD by cube root of birthweight. Of the 1154 infants examined, 624 were males and 71 had UDT. AGD was significantly shorter in infants with UDT when compared with infants with descended testis (mean ± SD; 2.21 ± 0.36 versus 2.56 ± 0.31 cm; P < 0.001). AGDi was also significantly shorter in infants with UDT (mean ± SD; 1.68 ± 0.27 versus 1.81 ± 0.20 cm/kg⁻³; P < 0.001). Significance was maintained even when preterm (P < 0.001) and low birthweight boys (LBW) (P < 0.001) were excluded. SPL was also significantly shorter in infants with UDT (Mean ± SD; 3.08 ± 0.52 versus 3.31 ± 0.38 cm; P < 0.001) but the significance was not maintained when preterm (P = 0.119) and LBW boys (P = 0.666) were excluded. Birthweight, gestational age and length adjusted regression models showed significantly shorter AGD in infants with UDT, but SPL was not different. Infants with higher position of testis appeared to have a shorter AGD and SPL but the correlation did not reach statistical significance. No difference in AGD or SPL was noted between boys with unilateral and bilateral UDT. The present study did not include data pertaining to maternal or newborn health status. Also parental drug exposure or occupational exposures to endocrine-disrupting chemicals was not studied. These may possibly affect genital anthropometric measurements. The study strengthens the hypothesis of existence of MPW in humans. Shorter AGD in cryptorchid infants may reflect the effect of androgen disruption or deficiency during MPW. AGD may be a more reliable non-invasive marker of androgen action during MPW than SPL to predict reproductive outcomes in humans.

Prenatal exposure to stressful life events is associated with masculinized anogenital distance (AGD) in female infants

In animal models, prenatal stress programs reproductive development in the resulting offspring, however little is known about effects in humans. Anogenital distance (AGD) is a commonly used, sexually dimorphic biomarker of prenatal androgen exposure in many species. In rodents, prenatally stressed males have shorter AGD than controls (suggesting lower prenatal androgen exposure), whereas prenatally stressed females have longer AGD than controls (suggesting greater prenatal androgen exposure). Our objective was to investigate the relationship between stressful life events in pregnancy and infant AGD. In a prospective cohort study, pregnant women and their partners reported exposure to stressful life events during pregnancy. Pregnancies in which the couple reported 4+ life events were considered highly stressed. After birth (average 16.5months), trained examiners measured AGD in the infants (137 males, 136 females). After adjusting for age, body size and other covariates, females born to couples reporting high stress had significantly longer (i.e. more masculine) AGD than females born to couples reporting low stress (p=0.015). Among males, high stress was weakly, but not significantly, associated with shorter AGD. Our results suggest prenatal stress may masculinize some aspects of female reproductive development in humans. More sensitive measures of prenatal stress and additional measures of reproductive development are needed to better understand these relationships and clarify mechanisms.

Dichlorodiphenyldichloroethylene exposure during the first trimester of pregnancy alters the anal position in male infants.

Anogenital distance (AGD) at birth is regarded as a useful measurement that reflects the prenatal androgenic status in rodents. However, the impact of xenoantiandrogens on human development is largely unknown. The aim of this study was to evaluate the potential antiandrogenic impact of prenatal DDT metabolites (p,p'-DDE and p,p'-DDT) exposure on infant AGD, using a non-age-dependent anal position index (API). As part of an ongoing perinatal cohort study on the effects of organochlorine pesticides in children's neurodevelopment, we conducted a cross-sectional study in 71 infants (37 males and 34 females). Maternal serum levels of DDT metabolites (p,p'-DDE and p,p'-DDT) before and during each trimester of pregnancy were determined by electron capture gas-liquid chromatography. During postnatal home visits at 3, 6, and 12 or 18 months of age, the children's weight and API were evaluated. Multiple lineal regression models were used to estimate the potential endocrine disruptor activity of prenatal p,p'-DDE exposure. Boys had significantly higher API values than girls (0.6 versus 0.5; P < 0.001). Only among boys, a doubling increase of maternal p,p'-DDE serum levels during the first trimester of pregnancy, were associated with a significant reduction of API (beta=-0.02; P= 0.02). No effect of p,p'-DDT on AGD was observed. Evidence of the effect of prenatal p,p'-DDE on external genital differentiation is scarce and not consistent in the literature. Further studies are needed to confirm a hormonal disruptive effect on the development of external genitalia, due not only to p,p'-DDE but also due to other antiandrogenic persistent compounds.