The menstrual cycle

Question 1

How often does the menstrual cycle occur?

Answer 1

about every 28 days

Question 2

stage 1

Answer 2

menstruation

days 1 - 5

the uterus lining breaks down and exits through the vagina

Question 3

stage 2

Answer 3

days 6 - 13

the lining of the uterus gradually builds up

Question 4

stage 3

Answer 4

ovulation

day 14

an egg is released into the fallopian tubes by an ovary

Question 5

stage 4

Answer 5

fertilisation

days 14 - 16

fertilisation is most likely to take place now

the egg travels down the fallopian tubes

Question 6

stage 5

Answer 6

days 17 - 28

the lining of the uterus continues to build up

if fertilisation does occur, the uterus lining is maintained and menstruation does not happen
otherwise, the cycle restarts

Question 7

What happens to the uterus lining if fertilisation does occur?

Answer 7

it stays thick so that the embryo can embed into the lining and obtain the nutrients it needs

Question 8

What is contraception?

Answer 8

the prevention of fertilisation

hormonal contraception and barrier methods

Question 9

Explain the types of hormonal contraception

Answer 9

hormone pills
implants or injections

hormones are released to prevent ovulation
mucus at the cervix is thickened to prevent sperm from passing

Question 10

Explain the types of barrier methods

Answer 10

male and female condoms
the diaphragm
caps and sponges
intrauterine devices (IUD) or a coil
spermicidal agents to kill sperm
abstaining
surgical methods

the sperm is stopped from reaching the egg

Question 11

Give one advantage and disadvantage of hormonal contraceptives compared with condoms

Answer 11

hormonal contraceptives are more effective than condoms at preventing pregnancy (>99% to 98%)

condoms prevent against STDs while hormonal contraceptives do not

Question 12

What are the success rates of the different methods?

Answer 12

when used correctly:

condoms: 98%
can tear or rip

diaphragm/cap: 92-96%
they have to be put in before sex and left in for several hours afterwards

hormonal methods: >99%

Question 13

Explain why failure to menstruate may be the first sign of pregnancy.

Answer 13

if the egg is fertilised the uterus lining is maintained

so menstruation does not occur

Question 14

Use the information to evaluate the benefits and problems that may arise from using contraceptive pills to control fertility.

Around 1/3 of UK women of reproductive age take a contraceptive pill. If used properly, the pill is 100% effective against pregnancy.
Studies over 40 years show that the pill reduces the risk of many cancers.
If the women smokes heavily or is obese, taking the pill greatly increase the risk of thrombosis (blood clot).
The increase in risk of thrombosis for women who do not smoke or are not overweight is very small, and is far less than the risk of thrombosis during pregnancy.

Answer 14

contraceptive pills are very effective at preventing pregnancy, so a couple can decide when they want to have children

the pill has positive side effects, such as reduced risk of some cancers
some negative effects, such as a higher risk of thrombosis

as long as a women does not smoke heavily and isn’t obese, the benefit of controlling fertility outweighs the risk of side effects

Question 15

How does oral contraceptive work?

Answer 15

it contains oestrogen or progesterone, or a combination of both

the hormones inhibit the production of FSH, so eggs cannot mature

Question 16

What are the risks of hormonal contraception?

Answer 16

too high levels of oestrogen can cause changes in weight, mood, and blood pressure

Question 17

How do contraceptive injections, implants, and skin patches work?

Answer 17

they contain slow release progesterone to inhibit the maturation and release of eggs by inhibiting FSH and LH

Question 18

How do intrauterine devices (IUD) / the coil work?

Answer 18

prevent the implantation of an embryo or release of a hormone

they can remain in position for up to 10 years