2.3 The biology of controlling fertility

State type of fertility for female

cyclical

State type of fertility for male

continuous

State 2 indicators for female fertile period

- rise in temperature ~0.5 degrees (sustain throughout luteal phase)
- thinning of cervical mucus (increase in viscosity after fertile period passed)

State length of female fertile period

usually 2 - 3 days after ovulation

State 4 methods to help with fertility

- stimulating ovulation
- artificial insemination
- intracytoplasmic sperm injection
- in vitro fertilisation

How can ovulation be artificially stimulated

via drugs

State 2 types of drugs that could be issued to stimulate ovulation

- prevent negative feedback control of oestrogen on FSH and LH
- or mimics effect of FSH and LH to bring about super-ovulation

Why is artificial insemination or intracyptolasmic sperm injection used

if the male has low sperm count/ quality

State steps of artificial insemination

- several sperm samples are collected and frozen
- artificially introduced to the female reproductive tract via other means

State steps of intracyptoplasmic sperm injection

- head of a mature sperm is inserted to an egg cell via a needle
- the egg cell is held in place with a holding tube

State steps of in vitro fertilisation

- bring about super ovulation via drugs
- surgically remove eggs cells from the ovary
- place egg cells in a culture dish with nutrient medium with sperm / ICSI
- fertilisation occur
- incubate embryos in nutrient medium for 2 - 3 days until cell count reaches 8 or above
- can be used in conjunction with pre-implantation genetic diagnosis (PGD) for mutations
- select 2 or 3 embryos and transfer to uterus for implantation
- remaining embryos are frozen and stored/ donated (others or stem cell research)/ destroyed

State possible issues with IVF

- multiple births (twins/ triplets)

State 2 types of pre-implantation genetic tests and their difference

PGS - pre-implantation genetic screening
- non specific screening for abnormalities/ mutations
PGD - pre-implantation genetic diagnosis
- specific diagnosis for abnormalities/ mutations

State 3 types of barrier contraceptives and their purposes

Condom, diaphragm, cervical cap - block sperm from reaching female uterus

How does IUD works and why is it preferred for long term

block sperm from reaching oviduct
- can stay for 5 to 10 years - placed in uterus through cervix

State the 2 sterilisation procedures

vasectomy (males) - cut and tie sperm ducts
tubal ligation (females) - cut and tie oviducts

State the 3 types of chemical contraceptives

combined pill, mini-pill, morning after pill

State the contents of the combined pill and how it works

synthetic oestrogen and progesterone
increase overall levels of oestrogen and progesterone levels in body - trigger negative feedback inhibition of FSH and LH - no ovulation

State the contents of the mini pill and how it works

synthetic progesterone
thicken cervical mucus

State the contents of the morning after pill and how it works

high doses of synthetic oestrogen and progesterone
prevent ovulation and implantation