When do babies start sucking their fingers in the womb?

Babies typically begin sucking their fingers around 11 weeks of pregnancy. At this stage, they can also make fists and grasping motions when the uterine walls brush against them.

What baby development happens at 11 weeks pregnant?

At 11 weeks, babies develop finger sucking abilities, rapid brain growth, breathing-like chest movements, and early sexual differentiation. The vestibular system also forms to help with movement coordination in amniotic fluid.

Can you determine baby gender at 11 weeks ultrasound?

While sexual differentiation begins around 11 weeks, external genitalia are still too small for accurate ultrasound determination. It's best to wait until later in pregnancy for reliable gender identification.

What can you see on 11-week pregnancy ultrasound?

You can clearly see the baby's head contour, facial features like forehead and nose, arm and leg positioning, and mouth movements. The baby often lies with arms crossed over their chest and legs bent.

Baby Names & Early Development: What Happens at 11 Weeks

The baby begins sucking their fingers [1]

At this stage, your baby not only starts to take their fingers to their mouth, but they can also make a fist and grimace. When the uterine walls brush against the baby, they may tremble and make grasping motions. An ultrasound also reveals the first movements of the baby’s chest, which are motions that resemble breathing. And at this time, an ultrasound can allow you to clearly distinguish a single pregnancy from a multiple pregnancy.

Brain development continues rapidly [1] with the differentiation of the cerebral cortex, and the main nuclei developing as part of the central nervous system. The new vestibular system is responsible for motion and spatial orientation. This helps the baby move around in the amniotic fluid. The circulatory system also develops and becomes more specialized. Blood circulation between mother and fetus becomes more effective, and the baby receives all needed nutrients for rapid, healthy growth.

During this stage of pregnancy, the baby develops a cartilage template for bones. It is also possible to detect early signs of milk teeth in the gums. Tiny vocal cords appear in the larynx and fluffy hair forms on the skin, to later become eyelashes and eyebrows.

At this point, sexual differentiation occurs under the influence of genetics and hormones. Testosterone develops external male genitalia, the penis, and the scrotum [2]. Because it is still early in the physical development of the baby, these organs are too small to be accurately determined through an ultrasound, so it is best to wait to determine the baby’s sex until later on.

The corpus luteum has been supplying needed levels of progesterone up until this point, but levels in the placenta are now high enough that it is no longer needed. Placental thickness by the end of this week is around 0.6 inches.

What we can see on an ultrasound

The baby will lie on their back, with their head and buttocks against the uterine wall. You should clearly see the contour of the head with the forehead, nose, eyelids, and lips. The head appears somewhat large, but soon it will become more proportionate to the rest of the body. The muscles of the mouth are already working, so you may see the baby open and close it and purse their lips. The baby may also raise and lower their eyelids.

The baby’s arms should be visible; a favorite position in the womb is to cross their arms over their chest. Bent legs are visible. The dark, hazy area is the amniotic fluid, which is constantly in flux.