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Boy or girl: when can you tell the baby’s sex?

Pregnancy

From the 9th week of pregnancy, it is possible to know the baby’s sex through a fetal sexing exam. However, sex identification is more common after the 1st trimester of pregnancy, and is done through an ultrasound examination recommended by the obstetrician.

Normally, a morphological ultrasound is the test that shows whether the baby is a boy or a girl and is indicated between the 18th and 22nd week of pregnancy. However, sometimes the baby’s sex can also be checked by obstetric ultrasound, especially if performed after 12 weeks of pregnancy.

Although the fetal sexing test is an option, it is usually a more expensive test. Therefore, it is recommended that women wait until the 18th week to undergo a morphological ultrasound.

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At how many weeks is it possible to know the baby’s sex?

The baby’s sex can be identified from the 9th week of pregnancy through the fetal sexing test, which is carried out on the mother’s blood. However, this exam is usually expensive and is not available through the public network and some health plans. Understand what fetal sexing is and how it is done.

How to know the baby’s sex?

It is possible to find out the baby’s sex through morphological ultrasound, which is an exam normally recommended by the obstetrician between 18 and 22 weeks of pregnancy, especially to check whether the baby is developing properly.

Obstetric ultrasound is another exam that can also determine whether the baby is a boy or a girl, and is carried out between the 10th and 13th week of pregnancy. However, it is difficult to identify the baby’s sex accurately when it is done before 12 weeks of pregnancy. See what obstetric ultrasound is for.

Is there a urine test to find out the baby’s sex?

In recent years, several tests have been developed that can be done at home to find out the baby’s sex, with urine testing being the most popular. According to the manufacturers, this type of test can be done at home and helps pregnant women find out the baby’s sex through the reaction of hormones present in urine with the test crystals.

Although its effectiveness is defended by manufacturers, These tests do not have scientific proof and, therefore, are not commercialized or authorized by Anvisa. Furthermore, the fact that discovering the baby’s gender is not interfered with by hormonal issues reinforces the lack of effectiveness of these tests.

Therefore, to find out the sex of the baby, it is recommended that a fetal sexing exam and/or ultrasound be carried out, in accordance with medical advice.

We regularly update our content with the latest scientific information, so that it maintains an exceptional level of quality.

Bibliography
  • ALHUR, Norah F. et al. Fetal Nucleated Red Blood Cells Preferable Than Cell-Free Fetal DNA for Early Determination of Gender Among Invasive and Non-Invasive Source Using Novel Four Genes Multiplex PCR. Int J Gen Med. Vol. 14. 9697-9705, 2021
  • ACOG. Cell-Free DNA Prenatal Screening Test. Disponível em: <https://www.acog.org/womens-health/infographics/cell-free-dna-prenatal-screening-test>. Acesso em 17 mai 2023
  • MILAN, Miguel et al. Fetal sex determination in twin pregnancies using cell free fetal DNA analysis. Prenat Diagn. 2018
  • STORUP, Gitte. Fetal sex determination during ultrasonography: Should we focus on how rather than why?. AOGS. Vol.98, n.11. 1483-1484, 2019
  • STATPEARLS. Pregnancy Ultrasound Evaluation. 2023. Available at: <https://www.ncbi.nlm.nih.gov/books/NBK557572/>. Accessed on May 17, 2023
  • ACOG. Ultrasound Exams. Available at: <https://www.acog.org/womens-health/faqs/ultrasound-exams>. Accessed on May 17, 2023
  • ARFI, A. et al. First-trimester determination of fetal gender by ultrasound: measurement of the ano-genital distance. Eur J Obstet Gynecol Reprod Biol. Vol.203. 177-81, 2016
  • BRAZILIAN DIAGNOSTICS. Consent form – Fetal sexing. Available at: <https://www.labcarloschagas.com.br/download/arquivos/sexagem_fetal.pdf>. Accessed on September 30, 2021
  • BRAZILIAN DIAGNOSTICS. Fetal sexing. Available at: <https://www.diagnosticosdobrasil.com.br/wp-content/uploads/2015/03/Sexagemfetal_lamina-1.pdf>. Accessed on September 30, 2021
  • NHS LOTHIAN. PREDICTING YOUR BABY’S SEX BY TESTING FETAL DNA IN YOUR BLOOD. 2018. Disponível em: <https://services.nhslothian.scot/clinicalgeneticsservice/Information%20Leaflets/Documents/Predicting%20your%20baby%27s%20sex%20by%20testing%20fetal%20DNA%20in%20your%20blood.pdf>. Acesso em 11 set 2019
  • BABYCENTER. When and how can I find out my baby’s sex?. Disponível em: <https://www.babycenter.com/0_when-and-how-can-i-find-out-my-babys-sex_20004784.bc>. Acesso em 11 set 2019
  • PARENTS. When Can You Find Out the Sex of Your Baby?. Disponível em: <https://www.parents.com/pregnancy/my-baby/gender-prediction/qa-how-soon-can-you-find-out-babys-sex/>. Acesso em 11 set 2019
  • ALFREDO NASSER FACULTY – 4TH RESEARCH SEMINAR. Precision and procedures for fetal sexing. 2016. Available at: <http://www.faculdadealfredonasser.edu.br/files/Pesquisar_4/05-12-2016-21.26.48.pdf>. Accessed on April 12, 2019
  • GEGENERA – INNOVATION IN HEALTHCARE. Frequently Asked Questions – Fetal Sexing. Available at: <https://www.genera.com.br/faq-sexagem/>. Accessed on April 12, 2019