Life Before Birth
From the moment of conception, 46 chromosomes with 30,000 genes combine to determine all your physical characteristics: sex, facial features, body type, color of hair, eyes, and skin. Even more amazingly, intelligence and personality – the way you think and feel – were already in place within your genetic code. At the moment of conception you were essentially and uniquely you!
You progressed from a single cell to a tiny human being with all organs present and functioning. The rest of your time in the womb was devoted to refinement, growth and practice. While still in the womb you began to move, swallow and “breathe” amniotic fluid, to react to stimuli and generally prepare yourself for life on the outside.
A Beating Heart
Just like you, your baby’s heart first started to beat between 18-20 days. The blood of the baby passes along the umbilical cord, runs through the placenta and approaches the maternal blood vessels found in the womb. Across the dividing wall, the two blood supplies exchange their gaseous loads; the baby passes to his mother his carbon dioxide waste and she passes to her baby oxygen and nutrients.
The baby has become sensitive and responds to touch. All five major areas of the adult brain are present. Brain function, as measured by EEG waves, has been recorded as early as 40 days. Here the marvelous control center sends out messages to the mother and the baby. The head takes up about one third of the body’s total volume but will begin to become more proportionate to the rest of the body as the baby grows older.
The baby lives inside a transparent membrane called the amniotic sac. The sac is filled with a salty solution which bathes the body’s cells. In a complex process – the body recycles the fluid, swallowing some, absorbing some, expelling some – while at the same time manufacturing most of it. The embryo floats almost weightlessly in the fluid so it is protected from shocks and does not have to fight gravity.
Hands and Feet
The arms begin to form at about 3 weeks and the fingers from 6 weeks on. The baby can close his fingers and thumb and he will open his mouth in response to pressure applied at the base of the thumb. At first when his hands touch his mouth the baby turns his head away, though his mouth opens. Later he may turn his head towards his hands and put his finger into his mouth to suck it. Finger nails are present at 7 months.
The baby’s legs and feet develop a little later than his arms and hands. At about 9 weeks, in response to a touch on the sole of his foot, he will curl his toes or bend his hips and knees to move away from the object. From 2 months, the footprints are already engraved in the skin. He starts to make slow movements, sharp kicks and small rhythmic kicks.
Sound and Vision
The baby is surrounded by loud noise such as his mother’s heart beat or loud music. He responds to sounds in frequencies so high or low that they cannot be heard by the human adult ear, which suggests that sensory pathways other than the ear are implicated. He responds to different noises, including his mother’s voice, and is in tune with the life-rhythm of his mother – he often wakes and sleeps with her.
Muscles within the orbit of the eye are present very early in pregnancy, and the baby’s eyes move when he changes position and during sleep. Light penetrates through the uterine wall and amniotic fluid, and fetal activity increases in response to bright light. The eyelids will remain closed until the 7th month to protect the eyes. Repeated flashing of a light will quiet a preterm baby.
The baby starts making spontaneous movements at about seven weeks but the mother does not usually feel the baby moving until about 16 weeks. At 11 weeks the baby swallows the amniotic fluid and passes it back into his urine. He can also produce complex facial expressions and even smile. At 18 weeks he is active and energetic and does a lot of muscle-flexing. It can make an impressively hard fist and punches and kicks.