physiology behind contraceptive methods.pptx

7/31/2019 physiology behind contraceptive methods.pptx

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Dr. Niranjan Murthy HL

Associate Professor

Department of Physiology

SSMC, Tumkur


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Preventive methods to help woman avoidunwanted pregnancies

A method or a system which allows intercourseand yet prevents conception

Include temporary and permanent methods

Cafeteria choice


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Barrier Methods

(a) Physical methods:(i) Condom:

Nirodh

Failure rate of 2-3/100 women years

Advantages: Safe, inexpensive, easy to use,

prevent STD, no side effects

Disadvantages: May slip off or tear, Interferes

with sexual sensation


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(ii) Diaphragm:

Dutch capSynthetic rubber or plastic

Spermicidal jelly is used

Failure rate 1.9/100 women-yearsAdvantages: no risks and no medical

contraindications, prevents STDs

Disadvantages: needs practice at insertion,privacy, cant be used immediately after childbirth, Toxic Shock Syndrome


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(iii) Vaginal sponge:

Today

Polyurethane foam sponge soaked in

nanoxynol-9

Less effective than diaphragm

Prevents STDs

Toxic Shock Syndrome


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(b) Chemical methods:

Spermicides were widely used in 1960s

Foams, Pastes, Jellies, Creams, Suppositories,

Soluble films

Modern spermicides are surface active

agents- inhibit oxygen uptake of sperms

Disadvantages: must be applied immediatelybefore intercourse, high failure rate, may

cause irritation


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(b) Intrauterine Devices:

On-medicated and Medicated

(i) First generation IUDs: inert Lippes loop

spirals, coils, rings, bows, loops

Barium sulphate Tails made of nylon


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(ii) Second generation IUDs:

Metallic copper was added

Smaller devices which fit into nulliparous copper-7; Copper T-200; T Cu-220 C; T Cu-

380 A; Nova T, ML-Cu-250

low expulsion rate, easier to fit, nulliparous,post-coital, more effective


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(iii) Third generation IUDs:

Release of hormoneProgestasert

Mechanism of action of IUDs:Foreign body reaction

Copper alters biochemical composition ofcervical mucus

Hormonal devices maintain sustained high levelsof progesterone


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Failure rate of 3-5/100 women-years

Maintained for 2-4 yearsAdvantages: simple, Inexpensive, no systemic side-

effects, high continuation rate

Contraindications: suspected pregnancy, PID,Cancer of cervix, uterus

Timing of insertion: during menstruation or 10 dayswithin the beginning; 6-8 weeks after delivery

Disadvantages: Bleeding, Pain, Pelvic infection,Uterine perforation, Pregnancy, Ectopicpregnancy


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(c) Hormonal contraceptives:

I. Oral pills:

A. Combined pill

B. Progestogen only pill

C. Post-coital pill

D. Once-a-month pill

E. Male pill

II. Depot formulations:

A. Injectables

B. Subcutaneous implants

C. Vaginal rings


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Combined pill:

Mala- N: Levonorgesterol + Ethinyl Estradiol

Mala- D: Levonorgesterol + Ethinyl estradiolPackage of 28 pills

Progestogen-only pill:Minipill or micropill

Norethisterone or levonorgesterol

Poor cycle controlMay lower HDL


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Post-coital contraception:IUDs

Hormonal pills

I pillOnce-a-month pill:

Failure

Male pill:

Gossypol a derivative of cotton-seed oil


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Mechanism of OCP action:

Inhibit ovulation by feedback inhibition of LH

& FSH

Progestogen render cervical mucus thick

Progestogens inhibit tubal motility

Failure rate: < 1 per 100 women-years

Adverse effects: Cardiovascular side effects,

cervical cancer, hypercoagulability of blood,

weight gain, liver disorders, breast tenderness


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(d) Postconceptional methods:

(i) Menstrual regulation

(ii) Menstrual induction: prostaglandins

(iii) Abortion


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(e) Miscellaneous:

(i) Abstinence

(ii) Coitus interruptus

(iii)Safe period or rhythm method

(iv)Natural methods

- Basal Body Temperature

- Cervical mucus method

(v) Breast feeding


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Rhythm method (Calendar method):

Ovulation in 28 day cycle between 12-16 days

Ova can survive for 1 day

Sperms can survive for 3 days

Unsafe period is between 9 and 17 days in 28

day cycle

Shortest cycle minus 18 days and longestcycle minus 10 days


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Basal body temperature:

Reliable for post-ovulatory period

increase in BBT by 0.5 C during ovulation

Billing method:

Cervical mucus becomes slippery and wateryclear during ovulation


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Terminal methods

(a) Male sterilization: Vasectomy

Simple and short duration surgery

Spermatogenesis and hormonal production

are not affected

Sperms are phagocytosed

Not sterile till 30 ejaculations

Complications: operative complications;spontaneous recanalization; sperm granules;autoimmune response


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(b) Female sterilization: Tubectomy

Laporoscopy, minilaparotomy

6 weeks after delivery

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