2.  Fertilization- Only one sperm fertilizes the egg. In the first week the egg undergoes many cell divisions and travels to the uterus.  Zygote- United sperm and egg  Cell division- From the two cell stage till about nine weeks the growing structure is called an embryo.

3.  The Blastocyst- 5 days after fertilization the embryo reaches the uterus where it floats free for a few days. At this time made up of 50- 100 cells. The structure is now called a blastocyst and is a sphere of cells surrounding a hallow center.  Implantation- The blastocyst begins to attach itself to the wall of the uterus.

4.  Amniotic Sac- Surrounds the embryo and is filled with amniotic fluid.  Placenta- Attachment holding the embryo to the wall of the uterus. Oxygen, nutrients and blood pass through to the embryo through the placenta. Harmful things can pass too..Like?  Umbilical cord- 25 days after fertilization this rope like cord develops between the embryo and placenta.

5.  During the first 2 months of development major body systems and organs start to form.  By the end of 8 weeks the embryo is about an inch long and has recognizable external features(eyes, nose, limbs ect)  The thrid month until birth the developing human is called a fetus.

6.  During this time the fetus kicks and moves which shows muscle development.  As the nervous system develops, the fetus becomes sensitive to light, sounds, and alternates periods of activity with periods of sleep  7-9 months the fetus grows in proportion to the size of the head. At 9 months the fetus is born.

7.  Zygote- Sperm fertilizes egg  Embryo- From 2 cell stage until 9 weeks  Fetus- Three months until birth

8.  Labor: 2-24 hrs or longer. Strong contractions of the muscles of the uterus cause the cervix to dilate.  Each contraction lasts approximately 30-90 seconds. At first they may be minutes apart but are usually only a few seconds apart at the end of the birth process.  Amniotic sac breaks and cervix becomes softer and wider.

9.  Delivery of the baby: Takes 30 mins- over 2 hrs.  Contractions of the uterus continue and the baby is pushed out, usually head first, through the cervix and vagina.  Doctor will then clamp and cut the umbilical cord, which has no nerve endings.  Nose and mouth are suctioned  Eye drops added to prevent infection  An injection of vitamin K to prevent excess bleeding from umbilical cord  Heel is pricked to check blood for protein levels

10.  Delivery of after birth: Contractions of the uterus push out the placenta.  This stage takes typically 15-30 mins

11.  This is the 6 week period of adjustment for the parents and new born.  Circulatory system and heart under go changes that send more blood to the lungs, because the baby now gets its oxygen there.  Nervous system reacts to sensations.  The new born is learning to build a close bond with its mother and father and is learning to get what it needs for survival.

12.  Mother: Changing hormone levels tell the body to produce milk and cause the uterus to gradually shrink to normal size.  Mother may feel overwhelmed or very sad.  If this depression lasts longer or causes the mother to withdraw from the baby or people, she should seek prompt medical help.  This means she could have postpartum depression.

13.  Cesarean Section- A surgical method of birth. Done when a mothers hips are too narrow or illness or other conditions are present.  Stillbirth- Occurs when the fetus dies and is expelled from the body after the twentieth week of pregnancy.

14.  Premature birth- Delivery before 37 weeks. The baby is not fully developed and complications can arise.  Low birth weight- Some are premature while others just have not grown enough before birth. Can reduce the chance of this happening by practicing healthy habits during pregnancy.

15.  Identical twins- Develops from a single fertilized egg. Embryo divides into two separate embryos.  Fraternal Twins- Two eggs are fertilized by two sperm. Can be different sex.