Getting Pregnant
and
Making Babies
and
Making Babies
The man's penis is inserted into the woman's vagina. When he ejaculates ("comes") the penis spurts seminal fluid (containing millions of sperm) into the woman's vagina. The sperm then swim through the cervix into the uterus (and possibly into the Fallopian tubes) to meet the egg to fertilize it.
- Can fertilization happen at any time?
No. While a man releases sperm whenever he ejaculates, a woman usually releases only one egg each month. Most of the time the release of the egg (ovulation) happens in mid-cycle between menstrual periods. But figuring out the exact time of ovulation can be very tricky.
Why? Because a woman can ovulate at any time during her menstrual cycle, even during her period. So it's impossible to know for absolute sure whether she can or cannot get pregnant on a particular day.
- How long does it take for the egg and sperm to
meet?
That depends. Once a woman releases an egg, it can live up to 48 hours. But the sperm can live for 7 days inside a woman's body. That means that a woman and a man who have not practiced safe sex could actually start a pregnancy a whole week after they had sex!
Sperm are fast swimmers. They can swim one inch in eight minutes (and that's quite a long distance for a microscopic sperm to go!). If a sperm manages to make its way into the Fallopian tube as a ripe egg travels toward the uterus, there's a good chance fertilization will occur.
- How does fertilization happen?
Once the sperm meets the egg it needs to penetrates the egg's outer membrane (outer layer) and fertilization takes place.
- What happens next?
Within a few hours, the fertilized single cell egg begins to divide. (In 3-5 days the fertilized egg has become a cluster of up to 50 cells.)
- Next the fertilized egg takes a four day trip down
the
Fallopian tube to the
uterus
where it continues to develop.
- When the fertilized egg reaches the wall of the
uterus it "implants" (so it can get nourishment from
the blood supply in the walls). It is now called an
"embryo."
- After 8 weeks of development, the body's basic
systems are formed and it is called a "fetus". It is
about an inch long.
- At around 36 weeks (9 months), the weight of the original fertilized egg has increased 5 billion times, is about 17 inches long, and the baby is ready to be born.
Interested in learning about Birth Control Options? Interested in learning about Sexually Transmitted Diseases?
B I R T H
C O N T R O L - Next the fertilized egg takes a four day trip down
the
Fallopian tube to the
uterus
where it continues to develop.