Early Pregnancy - When New Life Begins

When does life really begin? In terms of pregnancy, conception is the beginning of the adventure, when an egg cell from the mother joins with a sperm from the father to create a fertilized egg. In most women, fertilization takes place in the fallopian tubes. In only moments, that egg will begin to divide, and in a few days, it will be a blastocyst – a bundle of millions of cells all ready to perform their crucial roles in developing an entirely new person.

The blastocyst continues its travels to the uterus, where it implants itself into the uterine lining. Some women experience slight cramping at this stage or even a small amount of spotting. Chemical signals are released at this point, alerting the mother's body to the presence of the pregnancy and preventing her immune system from attacking the blastocyst as a foreign body.

As the blastocyst burrows into the uterine lining, the cells in the blastocyst begin to form themselves into three layers, each with an important job to do. Some will form the placenta and umbilical cord, while others will form the baby, from head to toe, skin to brain, and spinal column to internal organs.

At only four weeks after conception, the baby's rudimentary heart begins to beat. The baby's mother probably knows she’s pregnant by now, as her period is two weeks late and she’s probably beginning to experience early pregnancy symptoms, such as nausea and increased appetite.

In terms of development, the number of changes that take place over the next eight to nine weeks is truly astounding. From only two cells, a baby will emerge – a human with all of its organs and limbs, right down to its fingers and toes and its own circulatory and nervous systems. By the end of the first trimester, all of the baby's organs will have formed; during the remainder of the pregnancy, they’ll continue to grow and develop. But even with all these changes, the baby is still only about the size of a grain of rice around week 7 of the pregnancy. The mother-to-be may not even be showing yet!

The baby begins moving around in the 10th week of pregnancy, although the baby is so small at this point that the mother-to-be probably won’t feel these movements. This will all change in another few weeks. An ultrasound at week 15 may show the baby sucking on its thumbs or fingers at it explores its aquatic world. By 20 weeks, the baby will have patterns of sleeping and wakefulness, much like those of a newborn, and by week 28, the baby will begin to recognize voices it hears often, particularly that of its mother.

New research has also shown that at this point, babies may begin remembering things as they can become habituated to certain sounds, learning that they don’t represent danger. By week 32, the baby would almost certainly survive if born, although he might have some trouble breathing on his own. By week 40 – the typical length of a pregnancy – the organs and body systems that began developing during the first trimester will have formed fully. The baby is now ready for life outside the womb.