Up to 26 weeks

Your baby is growing taller and stronger; and her movements are becoming more complex. She’s also showing signs of sensitivity, awareness, and intelligence. A baby born after 24 weeks of pregnancy could survive with specialized intensive care in a neonatal unit.

Your Baby’s Progress

She’s still red and skinny, but she’ll soon start to put on weight. Her skin may look very wrinkled, but this is because she doesn’t yet have much fat to plump it out. Her body is growing faster than her head, and by the end of this month her proportions are about the same as those of a newborn. Her arms and legs have their normal amount of muscle, her legs and body are, in proportion, and her bone are beginning to harden in the center. Lines start to appear on the palms of her hands. The brain cells she’ll use for conscious thought now start to mature, and she begins to be able to remember and learn. (In one experiment, babies in the womb were trained to kick in reponse to a particular vibration.)

The genitals of a boy and girl look completely different by this time; if your baby is a boy, testosterone-producing cells in the testes increase in number.

Her hearing Your baby can hear sound frequencies that you can’t hear. She’ll move more in response to high frequencies than to low ones and she’ll move her body in rhythm with your speech. From this month she will begin to respond to drum beats by jumping up and down. Some mothers say they’ve had to leave concerts because their unborn babies wouldn’t keep still.

If she hears a piece of music often, she may realize it’s familiar to her when she grows up – even if she can’t remember ever dat hearing it. Some musicians have said that they “knew” unseen pieces of music, and later found out that their mothers played the these to them while they were in the womb.

She’ll also learn to recognize her father’s voice from this month onward. A baby whose father talks to her while she’s in the womb can pick out her father’s voice in a roomful of people immediately after she is born. She’ll respond to it emotionally. For example, if she’s upset, she’ll stop crying when she hears her father talking and calm down.

Her breathing Inside her lungs, more and more air sacs are forming. They’ll continue to increase in number until she’s about eight years old. Around them, the blood vessels that will help her to absorb oxygen and expel carbon dioxide are multiplying. Her pair nostrils have opened, too, and she’s beginning to make breathing movements with her muscles, so that her system has plenty of breathing practice before she’s born.

Up to 22 weeks

By this time your baby has grown enough to have developed a nervous system and muscles that allow him to move around in your womb. Because he’s still so small, he can swim up and down and be in any position at any time.

Your Baby’s Progress

Up until about 19 weeks after your last period, your baby grows very rapidly. Now this growth rate slows down, apart from his weight gain, and he matures in other ways. He begins to build up his defense systems.

A sheath begins to form around the nerves in his spinal cord to protect them from possible damage. He also has his own primitive immune system, which will help to defend him from some infections. To make body heat and keep up his temperature, your baby needs some specialized fatty tissue. This is provided by a substance called “brown fat,” which began to form during the fourth month. Now, deposits of brown fat begin to build up in areas of his body such as his neck, chest, and crotch. This will continue until term. One of the reasons that premature babies are so vulnerable is that they don’t yet have enough brown fat, and so cannot keep themselves warm.

His skin will continue to grow, although it’ll be red and wrinkled because there’s so little fat underneath it. His body begins to get plumper from now on. The sebaceous glands (oil-producing glands in the skin) become active and make a waxy, greasy substance called vernix caseosa. This protects his skin during its long immersion in the amniotic fluid.

Your baby’s body is also covered with fine hair called lanugo. Nobody is quite sure why babies have this hair, but it may help to regulate the body temperature, or it may help hold the protective vernix caseosa in place.

His movements As his nerve fibers become connected and his muscles continue to develop and grow stronger, his movements become more purposeful and coordinated. He embarks on his own gymnastics program-stretching, grasping, turning-to build up his muscles, improve his motor ability, and strengthen his bones. These movements can make your abdomen sore.

Sex organs A boy’s scrotum is solid at this stage. A girl’s vagina starts to become hollow and her ovaries contain about seven million eggs, which will be reduced to about two million at birth. By the time she reaches puberty, she’ll have between 200,000 and 500,000 eggs, and she’ll release only 400-500 of these during her adult life-around one per month until menopause. Nipples and underlying mammary glands develop in both sexes.