Correlation of maternal concentrations of plasma testosterone with fetal sex in horses / Correlação das concentrações plasmáticas de testosterona materna com o sexo fetal em equinos

ABSTRACT: The objectives of this study were to evaluate the correlation of fetal sex and plasma testosterone concentrations between the 5th and 8th months of pregnancy in mares and to verify the applicability of this test to predict fetal sex. Blood samples were collected from 21 mares at 30-day intervals of between 150 and 240 days of pregnancy. Plasma testosterone was determined by radioimmunoassay and the sex of the foals confirmed at birth. The levels of maternal testosterone were higher in mares carrying female fetuses at months 5 and 8 (P < 0.05). Limit values were determined by analyzing the receiver operating characteristic (ROC) estimates: 35.5 pg/mL and 40 pg/mL for the 5th and 8th month, respectively. For the mares with plasma testosterone values equal to or above the threshold, gestation of female foals was predicted, and for those with plasma testosterone below the threshold values pregnancy of male foals was predicted. In the 5th month, the predictive values for male and female fetuses were 70% and 88.9%, respectively; the detection rates were 87.5% and 72.7%, and the total accuracy of the examination was 78.9%. In the 8th month, the predictive values for male and female fetuses were 80% and 90%, respectively; the detection rates were 88.9% and 81.8%, and the total accuracy of the examination was 85%. It was concluded that there was a correlation between fetal sex and plasma testosterone concentrations in pregnant mares. Prediction of fetal sex based on plasma concentrations of maternal testosterone can be performed in months 5 and 8 with 78.9% and 85% accuracy, respectively.

RESUMO: Os objetivos do estudo foram avaliar a correlação do sexo fetal com as concentrações plasmáticas de testosterona entre o 5° e o 8º mês de gestação na égua e verificar a aplicabilidade deste exame para a predição do sexo fetal. Amostras de sangue foram coletadas de 21 éguas, com intervalos de 30 dias, entre 150 e 240 dias de gestação. A testosterona plasmática foi determinada por radioimunoensaio e o sexo dos potros foi confirmado ao nascimento. Os valores de testosterona materna foram superiores nas éguas gestando fetos fêmeas aos cinco e oito meses (P< 0.05). Através da análise da curva ROC (receiver operating characteristic) foram determinados valores limites de 35,5 pg/mL e 40 pg/mL para o 5º e o 8° mês, respectivamente. Éguas com testosterona plasmática igual ou acima dos valores limites foram preditas como gestando fêmeas e éguas com testosterona plasmática abaixo dos valores limites foram preditas como gestando machos. Aos cinco meses, os valores preditivos para fetos machos e fêmeas foram 70% e 88,9%, respectivamente; as taxas de detecção foram 87,5% e 72,7% e a acurácia total do exame foi de 78,9%. Aos oito meses, os valores preditivos para fetos machos e fêmeas foram 80% e 90%, respectivamente; as taxas de detecção foram 88,9% e 81,8% e a acurácia total do exame foi de 85%. Conclui-se que houve correlação entre o sexo fetal e as concentrações de testosterona plasmática em éguas prenhes. A predição do sexo fetal baseada nas concentrações plasmáticas de testosterona materna pode ser realizada aos cinco e oito meses de gestação com 78,9% e 85% de acurácia, respectivamente.

Development of an Extraction Protocol for Fetal Sexing from the Fourth Week of Gestation by Real Time PCR

Abstract Low number of fetal cells in maternal blood limited the use of fetal materials in diagnostic and clinical applications. This research developed a technology which allowed the extraction of fetal DNA by a non-invasive method that offers no risk to the mother or fetus. A total of 132 pregnant women participated in this inquiry. The DNA extraction was performed employing an in-house method based on guanidine thiocyanate and magnetic bead. For the amplification it was used the Quantifier Y Kit™. The fetal sexing analysis of the 132 pregnant women were 100% in agreement with the ultrasound. Sensitivity and specificity for detection of Y chromosome sequences was possible using Real-Time Polymerase Chain Reaction since the 4th week of gestation. This non-invasive early determination could be employed in fetal gender and also to be extended to detection of genetic diseases in the shortest possible time avoiding invasive methods that puts the fetus at risk.

Pregnancy diagnosis, fetal quantification and gender estimation by ultra-sonography in ewes / Diagnóstico de gestação, quantificação e sexagem fetal por ultra-sonografia em ovelhas

The objective of this experiment was to evaluate the accuracy of gestation, fetal sexing and quantification diagnoses in ewes. Pregnancy and fetal quantification were diagnosed in 105 ewes at 35 days of pregnancy. For the fetal gender diagnosis sexing diagnose 55 ewes between 49 and 59 days of pregnancy were used. All exams were recorded on DVD for posterior analysis. After birth, lamb sex was recorded to determine fetal sexing precision. Data were analyzed by chisquare ( 2) or Fisher’s test, with a significance of 0.05. One hundred percent of pregnancy ultrasound diagnoses were correct. As for the fetal quantification diagnoses, there was an error of 12%. It was possible to diagnose the fetal sex in 87% of the 69 examined fetuses, and 90% of these were estimated correctly. The realtime ultrasound diagnoses were not different from the recorded DVD image diagnoses. Therefore, pregnancy diagnosis accuracy may reach 100%, differing from fetal gender estimation and quantification, which are dependent upon other variables such as fetal genderand examiner experience.

O objetivo deste experimento foi avaliar a acurácia do diagnóstico de gestação, quantificação e sexagem fetal em ovelhas. Foram realizados o diagnóstico de gestação e a quantificação fetal em 105 ovelhas aos 35 dias de gestação. Para o diagnóstico da sexagem fetal foram utilizadas 55 ovelhas com período de gestação entre 49 e 59 dias. As imagens de todos os exames foram gravadas em DVD para permitir posterior análise. Após o nascimento dos cordeiros, os respectivos sexos foram observados para determinar a precisão do exame de sexagem fetal. Os dados foram analisados pelo teste Qui- quadrado ( 2) ou Teste de Fisher, com nível de significância de 5%. Observou-se 100% de acerto no diagnóstico de gestação pela ultra-sonografia. Quanto ao diagnóstico de quantificação fetal, houve 12% de erro. Foi possível diagnosticar o sexo fetal em 87% dos fetos e destes, 90% estavam corretos. Os diagnósticos em tempo real não foram significativamente diferentes dos diagnósticos feitos após a observação de imagens gravadas em DVD. Portanto, a acurácia do diagnóstico de gestação pode alcançar 100%, diferente da quantificação e sexagem fetal, que dependem de outras variáveis como tipo de gestação e experiência do operador.