HBIO Year 11 Unit 2 - Ch 13 and 14 - Healthy Pregnancy, Contraception, STIs and Infertility

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Three main ways to prevent contraception:

• Abstinence: not having sex, most reliable method of contraception

• Prevent Fertilisation: prevent production of ova and sperm and prevent fertilisation of ova

• Prevent Development of fertlised ova: prevent implantation

Contraception

Intentionally preventing pregnancy from occurring

Enforced Abstinence

- iron chastity belt - 16th century
- effective

Detection of Ovulation

- Rhythm Method: if a female has a regular 28 day cycle, intercourse is avoided 4 days before and after day of ovulation (day 14)
- Temperature Method: record body temperature each morning. Ovulation is normally accompanied by a sharp drop in body temperature then a rise. Woman can have sex 3 days after temperature rise increases
- Mucus Method: ovulation is detected by observing changes in mucus production. Mucus changes from cloudy and sticky to clear, stretchy and slippery. After ovulation mucus becomes cloudy again. Sex is 'safe' when there is no mucus and is more then 3 days after clear mucus
- Symptothermal Method: combination of all 3 methods (rhythm, temperature and mucus)

Lactational Amenorrhea

- temporary infertility following childbirth
- amenorrheic: not menstruating
- very unreliable
- mother must be breastfeeding fully and under 6 months

Coitus Interruptus

- the man withdraws before ejaculating
- most unreliable
- does not consider pre-ejaculatory fluids which can contain sperm

Mechanical Barriers

Male condom, diaphragm, cervical cap, female condom

Chemical Barriers

Spermicides, Contraceptive Pill, Depo-provera, implanon, Nuva-Ring, Intrauterine Devices (IUDs), Hormonal contraceptives are currently under development for men

Male Condom

very thin latex rubber, rolled onto erect penis to trap semen, also provide protection against contraction of STIs

Diaphragm

thin rubber cap that fits across the top of the vagina and forms a barrier to the uterus, must be sized by a doctor, inserted before intercourse, used with spermicide to increase effectiveness, must remain in position for a minimum of 6 hours after sex to be effective

Cervical Cap

similar to diaphragm but smaller, fits over the cervix, both need to be left for 6 hours, barrier to uterus

Female Condom

lubricated sheath which lines the vagina, one end fits over the cervix the other over the folds of skin outside the vagina, gives protection against STIs

Spermicides

very unreliable when used alone but often used with other barrier methods. Works in 2 ways:
1. contains substance that immobilises sperm.
2. Physical Barrier (reaction with the moisture in vagina to form bubbles of CO2).

Contraceptive Pill

contain varying proportions of oestrogen and progesterone. Oestrogen based pills send false messages to the brain and prevent ovulation while progesterone based pills cause a mucus plug to form in the cervix, thus preventing sperm to enter the uterus. Combined pill contains both progesterone and oestrogen and Mini Pill contains only progesterone.

Depo-provera

injected progesterone that lasts 12 weeks

Implanon

capsule of progesterone injected under the skin (can last 3 years)

Nuva-Ring

oestrogen and progesterone infused ring inserted into the vagina (inserted for 3 weeks, 1 week off and repeat)

Intrauterine Devices (IUDs)

Highly effective and simple to use. small T-shaped divide made of copper or plastic inserted into the uterus by a doctor. 2 types: hormonal and copper. Copper IUD inhibits movement of sperm and cause changes to endometrium and Hormonal IUD release progesterone which inhibits ovulation and suppress development of uterine lining.

Emergency Contraception for Women

- used to prevent pregnancy after sex
- the 'morning after pill' can be used up to 72 hours after intercourse
- contain high levels of oestrogen and/or progesterone which prevent or delay ovulation, preventing sperm from reaching ova and prevent implantation

Sterilisation

Permenant method of birth control for both men and women where the anatomy of reproductive systems are altered so that sperm and egg are unable to meet.
- Vasectomy (males)
- Tubal Ligation (females)
- removal of sex organs

Vasectomy (Males)

- vas deferens is cut, preventing sperm from leaving the testes
- sperm production continues but the sperm are broken down and reabsorbed by the body

Tubal Ligation (Females)

- fallopian tubes are cut or sealed which prevents the ova moving into the uterus

Removal of Sex Organs

• performed when organs are diseased, affect the balance on sexual drive and body characteristics

• Castration: removal of testes

• Oophrorectomy: removal of ovaries

• Hysterectomy: removal of uterus, results in sterility

Sexually Transmitted Infection (STI)

- infections transmitted by close body contact, usually with genital organs. Caused by viruses, bacteria, fungi or parasites

Chlamydia

• Caused by bacteria

• transmitted by vaginal or anal sex with infected person. most people show no symptoms and are unaware they are infected

• Symptoms in males: inflammation of urethra which may or may not occur with a yellow discharge and burning sensations when urinating. If not treated can cause inflammation (pain and swelling) of the epididymis which can lead to infertility if not treated

• Symptoms in females: usually no symptoms, if not treated can lead to infertility. Pelvic Inflammatory Disease (PID) can also occur, which is inflammation of the uterus and fallopian tubes. Also, ectopic pregnancy can occur, which is inflammation of embryo outside of uterus

• there is an increased risk of premature birth or still born, or can pass to baby at birth

• Diagnosis: urinary test or a more accurate diagnosis is a swab from vagina, cervix or penis

• Treatment: treated with antibiotics

Gonorrhoea

- caused by bacteria, mainly affects the mucous membranes of the excretory and reproductive systems, the rectum and occassionally the eyes and throat
- Treatment: antibiotics
- Symptoms in males: inflammation of the urethra, burning of the penis, pain while urinating, yellow discharge, if untreated can spread and cause sterility, arthritis or problems with heart and eyes
- Symptoms in females: more serious as symptoms may go unrecognised which can lead to infertility, can be passed onto baby during birth, which could lead to an infection leading to blindness in the baby)

Syphilis

- caused by bacteria, diagnosed by a blood test
- affects men and women in the same way - follows four stages if untreated
- Symptoms:
1st stage: one or more small sores (chancres) appear near site of infection
2nd stage: range of symptoms, skin rashes, sore or ulcerated mouth/throat, mild fevers and prolonged flu-like symptoms (lasts around 2 years). Patient is highly infectious during this stage.
Latent Stage: symptoms go away although still infected but cannot be passed to others. Many last many years
3rd Stage (tertiary or late stage): only a minority of people will develop to this stage (eventually attacks bones, heart and nervous systems often leading to insanity and death)
- Treatment: antibiotics in early stages. May need surgery in later stages. Pregnant women can potentially pass this disease through placenta. Foetus can suffer permenant damage to heart, nervous system, joints or other organs. Antibiotics can treat both infected mother and foetus

Herpes

- Caused by herpes simplex virus (2 types)
1. Herpes simplex 1 - produces 'cold sores' but can also affect genitals
2. Herpes simplex 2 - produces blisters on genital organs
- transmitted by skin-to-skin contact
- first episode is usually the most severe and can be painful and distressing
- blistering can be accompanied by flu-like symptoms or a rash
- blisters break, forming ulcers and scabs
- although healing has occurred, some of the virus passes into the bloodstream where it remains for life in the nervous system
- the virus can then reinfect the skin or mucous membranes or genital organs at any time
- can be transmitted from infected mother to a baby during birth
- no cure
- treatment includes medication to reduce the symptoms

Genital Warts

- flat, raised or cauliflower-like growths
- Caused by HPV (human papilloma virus)
- a newborn can become infected during passage through birth canal
- some types of HPV cause cancer of the cervix but those that cause genital warts do not

human immunodeficiency virus (HIV) (Not important to learn in depth)

- weakens the bodies immune system so the infected person is more susceptible to infections and some forms of cancer
- generally leads to AIDS (Acquired Immune Deficiency Syndrome)
- retrovirus - contains core of RNA rather then DNA
- similar to other viruses, it is unable to reproduce itself
- infects white blood cells (T-lymphocytes)
- inside host cell, the virus uses an enzyme, reverse transcriptase to convert RNA to DNA
- DNA reproduces and infects more white blood cells
Stages of HIV:
- Acute infection: around 1 month, flu like symptoms. Immune response deals with the infection and person returns to health
- Chronic Infection: asymptomatic and can last 10 years or more. Virus continues to multiply but at a low rate.
- AIDS: person develops AIDS when immune system is so damaged that it cant resist any other infections

Trichomoniasis

- parasite
- infection caused by protozoan, spread via vaginal intercourse
- Symptoms in women: inflammation of mucous membranes of vagina and severe itching
- Symptoms in men: infection without symptoms, inflammation of urethra
- Treatment: antibiotics

Pubic Lice and Scabies

• cause intense itching in genital area

• both are parasites, lice are insects, scabies are mites

• transmission is not just by sexual activity if sharing the same bed (prolonged, warm and close contact)

• treatment: lotions that are applied to the skin

Infertility

Being unable to achieve pregnancy despite frequent unprotected sex over the period of at least a year

Sperm Production

For Sperm to fertilise an egg, it must be
- produced in sufficient quantities
- able to move in a forward direction
- able to penetrate the corona radiata and zona pellucida

Other factors affecting male infertility

- semen rather then flowing out of the urethra may flow into the bladder
- males immune system may develop antibodies for their own sperm
- blockages can occur, especially vas deferens
- hormonal imbalances can affect sex drive and sperm production

Factors that affect ovulation in terms of fertility

- as females get older, the number of healthy eggs remaining decreases, especially after the age of 36
- polycystic ovarian syndrome is a hormonal condition where the ovaries contain lots of partially formed follicles that fail to mature
- cancer treatment may also negatively impact ovulation

Other factors affecting female fertility

• blockages in uterine tubes can stop the egg from reaching the uterus

• blockages can be caused by:

• fibroids: benign growths in muscular parts of uterus

• infections like gonorrhoea or chlamydia

• damage, e.g ectopic pregnancies

• endometriosis

Infertility Treatments that allow unassisted fertilisation

Surgery, Ovulation Tracking, Ovulation Induction, Artificial Insemination

Surgery

- blocked uterine tubes and sperm ducts can be opened
- fibroids or endometriosis can be removed

Ovulation Tracking

- blood tests are used to detect the surge in Lutenising Hormone prior to ovulation
- sperm remains viable for 2-3 days in uterine tubes and egg for 24h
- Highest chance of conception occurs by insemination prior to ovulation

Ovulation Induction

- treats infertility due to hormonal imbalances
- 2 types of drugs are used, both use FSH to induce development of follicles
- hCG may also be used to trigger ovulation once follicle has matured

Artificial Insemination

- process where sperm is released via a catheter being inserted through the cervix
- sperm sample is injected and then able to naturally move through uterine tubes
- sperm is analysed, processed and concentrated prior to insemination
- chance of fertilisation is increased as more sperm make it to the uterine tubes
- suitable for: males with low sperm count or decreased motility, ejcaulation dysfunction, females with cervical scarring, same sex couples, single females

Success Rate of Artificial Insemination

- success rate for suitable females achieving a pregnancy is around 10-20% per cycle
- over 3-6 trials, 80% chance of getting pregnant
- in couples with no fertility issues, 96%

Assisted Reproductive Technologies

Gamete Intrafallopian Transfer (GIFT), In Vitro Fertlisation (IVF), Intracytoplasmic Sperm Injection, Surgical Sperm Retrieval

Gamete Intrafallopian Transfer

• performed when there are normal uterine tubes and adequate sperm

1. hormonal treatment to stimulate female to produce more then one egg

2. sperm and egg are collected and analysed

3. sperm and egg are mixed together in the lab

4. the mixture is inserted into woman's uterine tubes

• it is hoped that sperm will fertlise egg naturally and move down the uterine tubes and implant into the endometrium

• as other assisted reproductive technologies have improved, frequency of use has decreased

• requires surgery and pregnancy rates are relatively low

• chosen by some couples due to religious or cultural reasons

In Vitro Fertilisation

- used to overcome a range of fertility issues: blocked uterine tubes, ovulation disorders, endometriosis, fibroids, low sperm quality or production, unexplained infertility
- hormonal treatment is used so ovaries are stimulated so that multiple follicles develop and ovulation is controlled, as well as prepare the uterine lining
- blood tests and ultrasounds are used to determine when the eggs are mature
- the mature eggs are retrieved via a needle through the vagina to ovaries
- the eggs are fertilised by sperm outside the body
- one or more embryos are inserted via catheter into the uterus
- Australia has regulations regarding number of embryos transferred

Intracytoplasmic Sperm Injection

- used when males sperm count if low or insufficient quality
- a single sperm is injected into a single egg
- the resulting embryo is then transplanted into woman's uterus
- Fertilisation rates of 20-30% have been achieved but concern has been expressed that the technique may increase the incidence of birth defects

Surgical Sperm Retrieval

- some men are unable to ejaculate or very low numbers are released
- a needle is used to surgically remove sperm from testes or epididymis

Donor Gametes/Embryo

- used when a couple is unable to use their own gametes
- donors may donate sperm/egg or embryo

Surrogacy

- another woman carries the baby for the couple
- laws vary between states but payment beyond, expenses is illegal
- agreement between birth mother and parents are not legally binding

Ethical Considerations

when embryos are no longer needed, the options are:
- dispose of the embryos
- donate them to other couples
- donate for research
- many ethical, religious and other legal considerations involved in assisted reproductive beliefs

Costs of Assisted Reproductive Technologies

- very expensive, includes specialist, doctor consults, initial tests

Ultrasound

- uses inaudible, high frequency sound waves to produce an image of foetus
- info obtained from ultrasound: confirming pregnancy, estimating stage of pregnancy, determining stage of pregnancy, abnormalities of cervix or uterus, monitoring growth of foetuses, determining gender, evaluating anatomy of foetus, genetic screening and birth defects

Amniocentesis

- chromosome analysis: analyses cells from detect defective, missing or additional chromosomes (cells from amniotic fluid)
- carried out in 16th-20th weeks
- removal of 10-20mL of amniotic fluid (examined for abnormalities in the number of chromosomes or structure)
- only performed on women with high risk of birth defects
- involves a small risk of infection, miscarraige or damage to baby
- disorders detected by amniocentesis: down syndrome, cystic fibrosis, sickle cell disease

Chorionic Villus Sampling (CVS)

- obtains a specimen of foetal cells from chorion
- advantages over amniocentesis: testing can take place 9-19 weeks, can be tested more quickly (important if a birth defect is detected that may require termination
- disadvantage: risk of miscarraige following procedure is 2%

Blood Sampling

- some of babies DNA passes into mother's blood
- a test of the mother's blood is a non-invasive screening test that is able to detect general abnormalities
- available after 10 weeks
- blood tests can scan for: Trisomy 13, 18 and 21 or Turner Syndrome

Foetal Monitoring

- detect indicators of stress
- usually take place during labour and birth using ultrasound and ECG machines
- electrocardiography: procedure for recording electrical charges in heart

Fetoscopy

- Two types:
- stethoscope that listens to foetal heart beat
- fibre-optic scope that looks directly at the foetus
- is a very risky and difficult procedure only performed by speicalists
- examination of outward appearance of foetus may reveal: cleft lips and palate, missing or abnormal ears, deformed or absent limbs, and spinal abnormalities

Foetal Blood Sampling

• May be sampled to: diagnose chromosomal abnormalities, diagnose foetal anaemia, check foetal oxygenation, identify infections

• blood can be taken from: umbilical cord via percutaneous umbilical cord sampling or a foetal blood vessel, usually the liver or heart via fetoscope

• usually performed during weeks 18-22

• can detect genetic abnormalities 6 weeks after conception

• risk of miscarraige, infection, blood loss and premature rupture of amniotic sac

Biochemical Analysis

- assessment of marker proteins in newborns (used to detect PKU)
- testing blood for excessive amounts of phenylalanine
- analysing the urine for phenyl pyruvic acid
- assessment of marker proteins in amniotic fluid: alpha-fetoprotein are measured, high concentration suggests the foetus has a malformation of the spinal cord such as spina bilfida

DNA Probes

- a probe is a single-stranded sequence of DNA or RNA used to search for its complementary sequence
- DNA probe is labelled with a dye and then joined to the gene in question
- if the gene is normal, the DNA probe joins with the DNA segments with which it is structurally identical and shows them up
- If it is an abnormal gene, it does not show up and is identifiable as a gap in DNA being tested
- detects a range of genetic disorders like Duchenne muscular dystrophy and thalassemia