How a baby develops during pregnancy
This animation will show how your baby developsduring pregnancy. the navigation arrows below the animationscreen to play, pause, rewind or fastforward theanimation. This animation contains sound. Pregnancy usually lasts about nine months,or 40 weeks, and is divided into trimesters. The first trimester is from week one untilweek 12. The second trimester is between weeks 13 and26, and the third trimester
is from week 27 until birth If you become pregnant, your womb doesn'tshed its lining as it normally does at the end of the menstrual cycle, so your periods temporarily stop. This is because the egg, which has been released from one of the ovaries, has been fertilised by a sperm and you are in the early weeks of pregnancy.
Here we show the ovaries, the fallopian tubes, the womb and the vagina. The fertilised egg has already started todivide in the fallopian tube. It will continue to develop and grow in thewomb and is called an embryo at this stage. Here we show the embryo in the womb. By week nine the embryo has developed and is called a fetus.
At this point most of the organs, includingthe nervous system and heart are forming. Here we show the fetus in the womb. By the time you are 12 weeks pregnant, your baby is approximately 6cm (two and a half inches) long. At this stage, your baby's neck is uncurling
and the limbs are complete. The eyelids are still fused and the ears are forming. Here we show the baby, the umbilical cord, the placenta and the amniotic fluid. The umbilical cord connects the baby to theplacenta.
This is how your baby gets nutrients and howwaste (such as urine) is removed. In the second trimester, your baby's sex organsdevelop and other organs mature. The baby swallows amniotic fluid and passes it out through its digestive system. The kidneys start to work and pass small amounts of urine. Your baby can now hear,