EN
try amma today
An ultrasound can now reveal the baby’s sex
Pregnancy

An ultrasound can now reveal the baby’s sex

2 min readWeek 18
Key takeaways
2 min
  • Understand that baby's genitals are fully formed and visible on ultrasound at this stage of pregnancy.
  • Expect to see detailed fetal development including formed organs, bones, and distinguishable facial features.
  • Know that twin pregnancies may show earlier movement due to increased space occupation and less amniotic fluid.
  • Recognize that ultrasounds can clearly display brain hemispheres, heart chambers, and skeletal structure.
  • Learn that fingerprint patterns and sweat glands develop during this crucial developmental period.

Ultrasounds can reveal baby's gender when genitals are fully formed, typically around 18-20 weeks. At this stage, both male and female reproductive organs are completely developed and clearly visible on ultrasound imaging, allowing for accurate gender determination.

amma app

Track your pregnancy in the app

Personalized content for your pregnancy week

Download App

An ultrasound can now reveal the baby’s sex

The baby’s genitals are now formed [1]. Although the boys' testes are still in the abdominal cavity, they already have a penis, prostate, seminal vesicles, and the testes themselves. Girls have noticeable labia, a clitoris, a vagina, a uterus, fallopian tubes, and ovaries.

The baby's body is well formed, though the head might not look that large yet. Their upper and lower extremities are evenly developed, and the ratio in the lengths of the individual parts is correct. The phalanges (bones) of the fingers and toes are formed, and they have developed a fingerprint pattern.

With the growth and development of the muscular system, the baby's movements become more distinct. Under their influence, the cardiovascular system develops and the heart begins pumping more blood.

Sweat glands form and a subcutaneous layer of fat starts to develop, together they will help in thermoregulation when the baby is born.

If your partner is expecting twins

At this time, your expectant partner will begin to feel the babies moving! Yes, a little earlier than single pregnancy moms. After all, twins take up more space than one baby and have slightly less fetal water in their sacs [2]. 

What we can see on an ultrasound

The ultrasound image shows the baby’s head from above and we can see its diameter. A bright horizontal strip is visible, which divides the brain into the right and left hemispheres, showing the formed bones of the skull.

An ultrasound can now reveal the baby’s sex - An ultrasound can now reveal the baby’s sex
Frequently asked questions

Baby's genitals are typically fully formed and visible on ultrasound between 18-20 weeks of pregnancy. Both male and female reproductive organs are developed enough for accurate gender determination by this time.

You can see the baby's head diameter, brain hemispheres, fully formed heart with visible chambers, and facial features like forehead, nose, and lips. The skeletal structure and organ development are also clearly visible.

Yes, mothers expecting twins often feel movement earlier than those with single pregnancies. This occurs because twins occupy more space in the uterus and have less amniotic fluid in their individual sacs.

All major organs are formed including reproductive organs, heart chambers, brain hemispheres, and skeletal system. Sweat glands and subcutaneous fat layer also begin developing for temperature regulation after birth.

Medical Disclaimer

This article is for informational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your physician or qualified health provider with any questions you may have regarding a medical condition.

Meet our medical experts

Medically reviewed content

Reviewed by healthcare professionals · Updated September 7, 2024

This article is based on peer-reviewed research and trusted medical sources.

  1. The amniotic fluid index in normal twin pregnancies. Hill L. M., Krohn M., et al. Am J Obstet Gyneco

Track your pregnancy on the go

Rated 4.8417,594 reviews