By 11th week of your pregnancy your baby has grown to approximately the size of a small lime. By the end of this week, his organs are not only formed but are also working. As a result of this, your pregnancy is stronger, your baby’s development is not so vulnerable to environmental risk and the danger of you suffering miscarriage is reduced.
Your baby’s heart is working hard, pumping blood around his body and through the umbilical cord to the area that is developing into the placenta. His outer ears are moving from the neck to the sides of the head, and the middle and inner ears are completely formed. The ovaries and testicles have developed inside the body but your baby’s sex is not obvious from the outside because the genitals have not developed.
Most of the time, your baby will be in the fetal position, with chin bent down and knees curled up, but despite that, he is very active. His limbs remain quite short but they are undeveloped because he has not yet been moving them. The more he moves, the stronger his muscles will become, and this will encourage their growth. His head appears large and out of proportion to his body, but his face is more rounded with discernable features. Your baby is making more definite movements, moving his spine and stretching his arms and legs. He can even open and close his mouth.
By 12th week your baby has grown to about the size of a lemon. This stage of pregnancy, which marks the end of the first 3 months, often feels like a milestone for many women because the risk of miscarriage is reduced after week 12. The major development of your baby is complete and the emphasis is now on growth.
Although the placenta is small, it is now complete. Your baby’s ears have moved to the sides of his head and the remainder of his is now formed. His jaws have tooth buds in place, and he can suck and swallow. There is an unmistakable chin and his nose is more obvious. His eyelids are fused shut over his eyes and circulation is fully functioning, his kidneys are working, and his bones are becoming harder.
The muscles of your baby’s intestine are moving practicing peristalsis, the contractions used to move food through the bowels. The baby’s skin is very thin and translucent and the blood vessels are visible through it. His limbs are growing in length and are more in proportion to the rest of his body. Tiny nails are growing on his fully formed fingers and toes.
His external genitals are forming, although it would still be very difficult to determine the sex of your baby on an ultrasound scan. The movement of your baby will increase as the muscles in his limbs develop, although you will not be aware of them. He can even move his fingers, clenching and unclenching his hands.