Contraceptive Methods and Infertility

Contraceptive Methods

• Contraceptive Methods & Their Biological Basis.
• Dr Eleanor Peirce Anatomy & Pathology, School of Biomedicine Room N240, Helen Mayo North ': 831 35191 Email: eleanor.peirce@adelaide.edu.au

Learning Outcomes

• Identify the target sites for preventing pregnancy in the female and male reproductive systems
• Understand the biological basis of commonly used methods of fertility control/ contraception
• Explain the disparity in the number of female as compared to male contraceptive methods

Fertility Control. Why is it Necessary?

• To:
  • Curb population growth
  • Curb unintended pregnancy rates – up to 30% of pregnancies worldwide are unintended (Blumenthal et. al 2011 Human Reproduction Update 17:121-137)
    • Health, social & economic benefits
  • Delay births or increase interval between births
• No method of contraception is 100% effective

Artificial Control of Fertility

• Sterilisation
  • Irreversible, provides a permanent block to fertility
  • Targets the transport route taken by gametes
• Contraception (“prevention of conception”)
  • Reversible
  • Various targets including prevention of ovulation, contact between sperm and oocyte, fertilisation & implantation
• Induced Pregnancy Termination
  • Chemical or surgical abortion of the conceptus

Considerations in Selecting a Contraceptive Method

• Ease of use (Compliance – actual versus perfect use)
• Availability
• Efficacy & failure rate
• Contraindications & side effects of usage
• Additional health benefits (protection from STIs)
• Cultural factors – may relate to mechanism of action, religious beliefs
• Cost

Unintended Pregnancy with Typical Versus Perfect Use of Contraception

• Perfect use - 0.05-20% pregnancy rate
  • Least reliable methods = sponges & spermicides
• Typical use - 0.2-32% pregnancy rate
  • Least reliable methods = sponges, spermicides, withdrawal, fertility awareness, condoms, diaphragms

Major Fertility Control Methods UK Women Aged 16-49 In 2004-2005

• Main methods used world-wide:
  • Oral contraception
  • Intrauterine contraceptive devices (IUDs)
  • Male condom
  • Female sterilization
  • Injectable steroids
  • No fertility control

Sterilisation Methods

• Vasectomy
  • Tubes are cut and blocked
  • The tubes are closed and sperm are prevented from entering the semen
  • Sperm are re-absorbed into the body
• Tubal Occlusion/Ligation
  • Tied and cut, Banded, Cauterized, Clipped
  • Prevent contact between spermatozoa & oocytes

Sterilisation Methods Hysterectomy

• Normally only used in cases of uterine pathology (fibroids, premalignant disease) or irregular, painful & heavy menses
• Remove the site of implantation

Natural Methods of Fertility Control Rhythm Method

• Particularly risky at end of reproductive life due to irregularities in timing of ovulation
• Can be combined with:
  • daily assessment of body temperature
  • Billings' method for assessing cervical mucus
• Limit sexual activity to “infertile” phases of the menstrual cycle
• Requires:
  • Accuracy in detecting the time of ovulation
  • Knowledge of the usual viability of gametes in the female tract

Risk of Conception, Rhythm Method

• Sperm viable in female reproductive tract for ~ 6 days
• Ovulated oocyte viable for 12-24 hours
• Must allow adequate length of abstinence to prevent interaction of viable gametes

Natural Methods of Fertility Control Coitus Interruptus

• Withdrawal prior to ejaculation
• Prevent spermatozoa reaching the site of fertilisation
• Requires self control; no guarantee that zero spermatozoa will be deposited in the female reproductive tract

Barrier Methods

• Prevent sperm reaching the oocyte
  • Condom (male & female)
  • Cervical cap
  • Diaphragm
• Commonly used in conjunction with a spermicide (agent that kills sperm)
  • Applied as a foam, jelly, cream or in a sponge
  • Active ingredient = nonoxinol-9, a detergent that destroys the sperm membrane

Condoms

• Mechanism of action:
  • Barrier - prevents sperm from reaching & fertilising an oocyte
  • Provides protection against STIs, including HIV & stops their transmission from one sexual partner to another

Diaphragm & Cervical Cap

• Devices that fit inside the vagina & prevent sperm from passing through the entrance of the cervix
• Need to use in conjunction with a spermicide to be an effective contraceptive
• Combined barrier to sperm entry + killer (reduce numbers of viable sperm)

Steroidal Contraceptives

• Oral Contraception
  • Combined oral contraception (COC) – mono, bi- & triphasic regimes
  • Progestagen only pill (POP) = mini pill
• Injectable Contraceptives
• Subcutaneous Implants
• Postcoital/Emergency Steroidal Contraception (= morning after pill)
  • Oestrogen + progestagen (ethinyl estradiol - EE & levonorgestrel)
  • Levonorgestrel only
  • RU486/mifepristone (= antiprogestogen)
• Modify the normal hormonal environment à inadequate support of reproductive functions

Oral Contraceptives, Structure Synthetic Variants of Natural Oestrogens & Progestagens

• A. Progesterone – the naturally occurring progestagen
• B-D. Synthetic progestagens used orally or as subcutaneous implants
• E. Natural steroid in plants; prohibits sperm motility
• F. Antiprogestagen that blocks implantation

Target Sites of Oral Contraceptives

• Hypothalamic – pituitary axis
  • Negative feedback on GnRH & gonadotrophins
• Ovary
  • Suppress follicular activity & ovulation
• Uterus & cervix
  • Cause endometrial thinning
  • Bring about secretory changes to glycogen, cervical mucus

Combined Oral Contraceptive Hormone Regimens

• Sequential – oestrogen, then progestagen
  • Side effects, higher failure rate, breakthrough bleeding
• Monophasic, biphasic, or triphasic
  • 21 active tablets, 7 inactive
  • Contain ethinyloestradiol (EE) & progestagen (often norethisterone or megastrol acetate)
• Biphasic & tricyclic regimes rely more on preventing positive feedback of endogenous E2

COC Mechanism of Action 1

• Circulating levels of synthetic hormones suppress LH & FSH secretion by gonadotrophs of anterior pituitary
• Inability of follicles to mature to preovulatory stage
• High levels of oestradiol not produced
• No LH surge
• No ovulation high synthetic hormone -ve x low oestradiol

COC Mechanism of Action 2

• Progestagen acts on cervical glands – makes mucus viscous & impenetrable to sperm
• Slows or prevents sperm from reaching site of fertilisation in ampulla of oviduct
• Site of sperm deposition

COC Mechanism of Action 3

• Thins uterine endometrium
• Alters uterine secretory activity
  • Reduces secretion of glycogen
  • Reduces receptivity to blastocyst
  • Reduces capability to support implantation

Progestagen Only Pill

• Contains low doses of progestagen
• Does not inhibit lactation
• Mechanism of Action:
  • Work primarily by thickening the cervical mucus è prevents sperm from entering the uterus
    • Effects last only 22-26 hours; must be taken promptly each day for reliable contraceptive effect
  • Ovulation suppressed in ~20% of users
  • Abnormal follicular-luteal activity in ~40% of users

Injectable Contraceptives

• Long-acting, effective, reversible on cessation of use
• Progesterone-only method
• Over 99% reliable in preventing pregnancy
  • fewer than 1 in 100 women who use injectable contraception will become pregnant each year
• Administered every 12 weeks

Contraceptive Implants

• Inserted under the skin on theinner side of the upper arm
• Contain a progesterone-like hormone that prevents ovulation & changes cervical mucus, thereby hindering sperm entry into uterus from cervix
• Slow release & long-acting – lasts for three years
• Close to 100 per cent effective
• Suitable for most women who are unable to tolerate synthetic oestrogens

Blood Progestagen Levels – Comparison of Injection, Implant, Progesterone Only Pill (POP)

• Pregnancy prevented if blood progestagen levels remain high (>2ng/ml^{-1})
• High progestagen levels suppress LH, è no LH surge or ovulation
• Readily metabolised Implant: steady release above ovulatory threshold
• Injection: very high dose that reduces with time
• POP: moderate dose that is readily metabolised (degraded)

Vaginal Ring

• Intravaginal ring impregnated with progestagen or EE + Progestagen
• Progestagen (levonorgestrel) saturates progesterone receptors & induces hostile mucus to prevent sperm penetration
• Does not block entrance of cervix

Steroid-Based Contraceptives, Comparison

• COC, combined (oestrogen and progestagen) oral contraceptive.
• POP, progesterone only pill.
• § By two mechanisms-no preovulatory follicles formed and/or no LH surges occur.
• Data adapted from J. Guillebaud, Contraception: your questions answered, Churchill Livingstone.

Emergency Postcoital Contraception

• Prevention of pregnancy after having unprotected sex, or if a method of contraception has failed
• Types of emergency contraception:
  • the emergency contraceptive pill – levonorgestrel, (sometimes called the 'morning-after pill’)
  • the copper intrauterine device (IUD)
  • mifepristone (RU486) has. limited availability in Australia
  • See http://www.phaa.net.au/documents/policy/policywomencontraception.pdf for usage policy in Australia

Emergency Postcoital Contraception Mechanisms of Action, Levonorgestrel EC

• Depending on timing, acts to prevent or delay the LH surge & hence follicular growth, ovulation & oestrogen output

Intrauterine Contraceptive Devices - IUDs Mechanism of Action

• Induce a low grade inflammatory response
• Leukocytes migrate into the uterine lumen è resembles serum transudate
• Changes intrauterine environment that reduce sperm transport to UTJ
• Impair blastocyst viability, implantation & decidualisation

Active IUDs Include Copper or Progestagen (IUS = Intrauterine System)

• Mechanism of action:
  • In addition to inflammatory mediated effects, release of spermo-toxic and/or embryo- toxic substances
  • Enhanced contraceptive effect over that of a passive IUD

Mifepristone – RU486 (Medical Abortion)

• Works by blocking the action of progesterone (binds to progesterone receptors) to cause a miscarriage early in the pregnancy
• Also used to treat a range of medical conditions, including endometriosis & cancer of the uterus
• Not widely available in Australia
• In Australia, a woman must be less than 9 weeks pregnant & in good health to have a medical abortion

Male Contraception Testosterone & Progesterone Injections (Dose: 200 mg T/Week)

• Action: blocks GnRH & hence gonadotrophin secretion è suppresses sperm maturation in testis
• Complete suppression of sperm not achieved in some individuals
• Gossypol
  • Extract from cotton seed oil used in cooking; results in shedding of seminiferous epithelium - is reversible in some individuals
  • May cause kidney damage
  • Action: inhibits lactate dehydrogenase X
• Non-hormonal vitamin A derivative???

Why the Disparity in ♀&♂ Targets for Contraceptive Methods?

• Easier to target and interrupt oocyte production than sperm production
• More potential sites to target in female reproductive system
• Greater consequences associated with unwanted pregnancy for women than men
• Different societal perceptions and economic impact of pregnancy between women & men, e.g. responsibilities for care etc.

Possible Future Contraceptive Methods Immunocontraceptive Vaccines

• Antibodies to zona pellucida proteins
• AntihCG
  • Immunise against a subunit, often coupled to larger protein e.g. tetanus toxoid
• Antisperm antibodies - e.g. PH20

Summary of Learning Outcomes

• Identified the target sites for preventing pregnancy in the female and male reproductive systems
• Understood the biological basis of commonly used methods of fertility control/ contraception
• Explained the disparity in the number of female as compared to male contraceptive methods

Infertility, Subfertility & Application of ART

• Dr Eleanor Peirce Anatomy & Pathology, School of Biomedicine Room N240, Helen Mayo North ': 831 35191 Email: eleanor.peirce@adelaide.edu.au

Learning Objectives

• Illustrate how knowledge of the normal structure and function of the male and female reproductive systems can be applied in understanding the causes and possible treatments for infertility
• Outline commonly used ARTs (assisted reproductive technologies)

Infertility & Subfertility - Definitions

• Infertility
  • “a disease of the reproductive system defined by the failure to achieve a clinical pregnancy after 12 months or more of regular unprotected sexual intercourse” (World Health Organisation)
• Subfertility
  • Failure to achieve pregnancy after 2 years of having regular, unprotected sex
  • In western countries sub- and infertility affect 15-20% of all couples trying to conceive (Evers, 2002 Lancet 360:151-159)
  • Male factor subfertility accounts for 25-30% of all cases (Taylor 2003 Br Med J 327:434-436)

Causes of Subfertility - Female & Male (In UK Couples Seeking Fertility Treatment)

Frequency (%)

• Causes of subfertility
• O+ Endometriosis Tubal damage Ovulatory problems defects Sperm Unexplained

Causes of Sub- & Infertility in the Female

1. Disorders of ovulation & absence of menstruation (1˚ & 2˚ amenorrhoea)
   • High gonadotrophin secretion
     • ovarian failure?
     • premature menopause?
   • Low gonadotrophin secretion
     • hypothalamic or pituitary failure
   • Gonadotrophin insensitivity
     • Oestrogen levels fail to rise
   • Follicular cysts
   • Polycystic Ovarian Syndrome (PCOS)
     • high testosterone, high BMI, hirsutism
   • Short luteal phase
2. Tubal Obstruction/Infection
   • Obstruction
   • Infection
     • Pelvic Inflammatory Disease?
3. Uterus
   • Poor endometrial receptivity
   • Endometriosis (endometrium in ectopic site)
4. Cervix – hostile cervical mucus
5. Loss of ovarian reserve – (lifestyle &) AGE!!

Maternal Age & Fertility

maternal Age (years)
Follicle Number

Optimal
Fertility
Decreased
Fertility
End of
Fertility
IrregularCycles

Failute of Oocyte Release from Follicle

Formation of a preovulatory follicle from a Graffian follicle relies on appropriate hormonal conditions – depends on development of LH receptors on mural granulosa cells & binding of LH to them

No mural LH receptors or LH insensitivity è no LH binding, no LH surge è no ovulation (follicle undergoes atresia)

Failure of HPG Axis

• Hypothalamic GnRH acts on gonadotrophs of anterior pituitary è secretion of LH & FSH
• LH binds to receptors on thecal cells è synthesis of testosterone from cholesterol
• FSH binds to granulosa cells, è conversion of testosterone into oestradiol
• Hormonal environment (high E2, LH surge) è follicle maturation & ovulation
• Therefore, failure of any of these events è no follicle maturation è no ovulation

Hormones During Menstrual Cycle No LH Surge = No Ovulation

• Peak of oestradiol mid-cycle brings about LH peak; (initiates resumption of meiosis in the oocyte & ovulation)
• At mid-cycle progesterone synthesis starts
• Post ovulation the corpus luteum secretes progesterone (& oestradiol); its life is determined by whether the ovulated oocyte becomes fertilised

Failure of Sperm Transport in Female

• Blockage of oviduct è no sperm passage è oocyte & sperm interactions cannot take place
• Sperm must pass through the cervix – if cervical mucus is hostile è no sperm passage

Failure of Embryo Transport or Implantation

• Slow/delayed transit of blastocyst towards uterus è missed implantation window è failure of implantation
• “Hostile” or unreceptive uterine environment è implantation failure

Causes of Subfertility in the Male

1. Impaired secretion of gonadotrophins
   • Hypogonadotrophic hypogonadism
   • High FSH
2. Sperm defects
   • Low number of sperm
   • No or reduced sperm motility
   • Abnormal sperm morphology
3. Accessory sex gland malfunction
4. Varicocoele - inadequate venous drainage & dilatation of spermatic vein
5. Testicular insult or trauma
   • Infection – mumps virus
   • X-irradiation
   • Antimitotic agents/chemotherapy
   • Insecticides
   • Heavy metals (cadmium, mercury, lead)
   • Maldescent of testes/cryptorchidism
6. Obstruction of epididymis or no vas deferens
   • can be congenital
   • associated with cystic fibrosis
7. Lifestyle factors
   • BMI, smoking, drug usage, excess alcohol

Semen Analysis

• These parameters are scored subjectively.

Fertility Treatments

• Aim to remediate or circumvent roadblocks to a normal, healthy pregnancy but
• May also remove safeguards that filter out embryos with sub- optimal characteristics
• Inherited infertility in subsequent generations

Reproductive Technology

• IVF (= In Vitro Fertilization)
• GIFT (= Gamete Intrafallopian Tube Transfer)
• SUZI (= Subzonal Insemination)
• ICSI (= Intracytoplasmic sperm injection)
• ROSNI (= Round spermatid nuclear injection)
• Cryopreservation of gametes
  • Cryoprotectants
  • Vitrification

Subfertility, Infertility & ART

• ART = assisted reproductive technology
• ART = tool for addressing some forms of subfertility & infertility, e.g. cycle irregularities
• Percentage of normal fertile cycles varies with age - increases during teenage years & then declines from around 40 years of age

Hormonal Induction of Follicular Development & Ovulation

• Induced by:
  • Administration of anti-oestrogen, clomiphene è suppresses gonadotrophin secretion via feedback
  • Withdrawal of clomiphene è rebound surge of gonadotrophin è ovulation; seen as a rise in progesterone (indicates formation of functional CL from the ovulated follicle) withdrawal

Steps in In Vitro Fertilisation Procedure

1. Ovarian hyperstimulation
2. Oocyte Pick-Up (OPU)
3. Sperm retrieval via ejaculation or surgery
4. In Vitro Fertilisation (IVF/ICSI)
5. Embryo culture
6. Transfer of the embryo/s
7. Cryopreservation (of additional embryos)

In Vitro Fertilisation 1

• Patient Selection – suitable for
  • FT blockage
  • Endometriosis
  • Immunological infertility
• Ovarian Hyperstimulation
  • Need multiple mature follicles
  • Often use GnRH agonist followed by HMG (human menopausal gonadotrophin)
  • Follicle development determined by ultrasound & serum oestradiol levels
  • HCG administration to prepare follicles for ovulation

In Vitro Fertilisation 2

• Oocyte Retrieval/Pick-Up
  • Usually done transvaginally; guided by ultrasound
  • Oocytes aspirated from follicles
  • Oocytes inseminated after about 4 hrs in culture

In Vitro Fertilisation 3

• Semen Preparation
  • Semen liquefies & centrifuged for sperm
  • Swim up or density gradient centrifugation performed
  • Motile sperm harvested

In Vitro Fertilisation 4

• Insemination
  • Sperm added to oocytes after several hours - when most oocytes at Metaphase II
  • Concentration of sperm added ca 100,000/ml (more if male infertility)

In Vitro Fertilisation 5

• Assessment Of Fertilisation
  • Ca. 18 hours after sperm added cumulus cells are removed
  • Oocytes examined for pronuclei & polar bodies

In Vitro Fertilisation 6

• Embryo Cleavage & Transfer

  • Embryos assessed for normal morphology
  • At 4-cell stage 1 blastomere may be removed for genetic analysis
  • Embryo transfer carried out at ca 46 hrs post -insemination at either 2 or 4-cell stage; maximum of 2 embryos placed in recipient uterus

• Other ART Procedures

Other Art Procedures

• Embryo Freezing
  • Slow Cryopreservation
  • Vitrification enables rapid freezing

1. Vitrification

• Embryos were immersed in equilibrium solution for 3min.

Transfer embryos into a tube containing vitrification solution with a glass capillary
5%DMSO+5%EG-PB1 50μl

Vitrification solution.
EFS42.5c-d 50μl.
(Directly Immerse in LN2/Slow Freezing/preservation in LN2)

ICSI Intracytoplasmic Sperm Injection - Started 1992

• When done? - when IVF fails, male has few sperm, or no vas deferens
• If no sperm found, testicular biopsy can be obtained
• For ICSI sperm aspirated tail first
• Pregnancy rate is best with testicular sperm

Key Point Summary

• Many possible causes of subfertility & sterility due to the complex nature of hormone-tissue interactions, gamete production & delivery, fertilisation, implantation & factors required to support a healthy pregnancy …
• Incidence of subfertility/infertility more apparent in western society as a consequence of life style choices … obesity, smoking, delayed parenthood
• Assisted reproductive technologies (ART) offer some hope for subfertile & infertile couples to have children

Summary of Learning Objectives

• Illustrated how knowledge of the normal structure and function of the male and female reproductive systems can be applied in understanding the causes and possible treatments for infertility
• Outlined commonly used ARTs (assisted reproductive technologies)