Birth and ways of birth control
Birth begins with a series of contractions of the muscular wall of the uterus, called labour, which push the baby out. In the ninth month the placenta loosens and progesterone falls, so the lining lets go of the uterus wall and the body is ready for birth. The baby starts life with a first cry, which sets the breathing system working. Then the placenta separates from the uterus wall and leaves the body, and the umbilical cord is cut on the baby’s side. From now on the baby’s food is the mother’s milk: pituitary hormones (prolactin, which stimulates the making of milk, and oxytocin, which makes the breasts release it, as in Week 4) bring the milk. The book calls it the most valuable food and emotional gift a baby can have. The book also says that 18 to 35 years is the suitable age for pregnancy and that problems are more common outside it; this describes large groups of people, not any one family, and a doctor gives the advice. Birth control means methods that prevent a pregnancy. The book lists four, and each blocks a different step from Weeks 9 and 10. Pills contain synthetic hormones like oestrogen and progesterone and stop ovulation, so no egg is released. The intrauterine device (the coil), placed in the uterus by a doctor, is described by the book as stopping a fertilized egg from implanting in the lining; it also makes the uterus a hard place for sperm to survive. The condom stops sperm entering the vagina. Surgical sterilization ties and cuts the two fallopian tubes in a woman, or each vas deferens in a man, so egg and sperm cannot meet. Choosing a method is a personal and medical decision, and a doctor or clinic gives the advice. This lesson only explains what each method does.
| Method | What it does | Step it blocks |
|---|---|---|
| Pills | stop ovulation | release of an egg |
| Intrauterine device | stops a fertilized egg settling in the lining | implantation |
| Condom | stops sperm entering the vagina | sperm reaching the egg |
| Surgical sterilization | ties and cuts the fallopian tubes or the vasa deferentia | egg and sperm meeting |
Card sorting, with a grown-up. Write the six events of birth on six small cards, shuffle them, and put them in order without looking. Then write the four methods of birth control on four cards and the step each one blocks on four more, and pair them. Check everything against the lesson. Nothing in this activity involves any real method: it is only about the biology.