1. Contraception Lecture by Dr.Mohammed Sharique Ahmed Quadri
Assistant professor ,Physiology
Al Maarefa College

2. Contraception
Is prevention of pregnancy before the implantation has taken place .

3. Methods of Contraception
Blockage of sperm transport to ovum
Natural Methods
Rhythmic abstinence
Coitus interruptus
Barrier methods
Use of spermicidal
Sterilization
tubal ligation
vasectomy
Prevention of ovulation
Hormonal contraceptive (OCP)
Blockage of implantation
IUCD
Emergency contraception/morning after pill

4. Natural Methods of Contraception
Rhythmic abstinence
Coitus interruptus
periodic or rhythmic abstinence i.e. avoidance of sexual intercourse during woman’s fertile period
Following methods are used
Calendar method:
The women predicts when ovulation to occur based on keeping careful records of previous cycles
First fertile period is shortest cycle minus 18 & last fertile period is longest cycle minus 10

5. Natural Methods of Contraception
Basal body temperature method:
Body temperature rises slightly a day after the ovulation
safe period is considered to begin after the basal body temperature remains elevated for 3 days
Cervical mucus method : ovulation time is determined by noting the consistency of the cervical mucus
Coitus interruptus: withdrawal before ejaculation

6. Barrier methods: prevents entry of sperm into vagina or uterus
For males (condom)
For females ( diaphragm or cervical cap )
Spermicidal:
Suppositories
Gel
Foam tablets
creams

7. Permanent Methods
Female sterilization ( i.e tubal ligation or Tubectomy)
Male sterilization (vasectomy):

8. Prevention of ovulation Hormonal contraceptive
Oral contraceptives
Combined pills
Progesterone only pill
Once a month pill
Injectable

9. Hormonal contraceptive(continued)
Oral contraceptives
Contains synthetic estrogen and progesterone like steroids (ethinyl estradiol & norgesterel/norethesterone)
Tablets are taken once daily for 21 days commencing at 5th day of menstrual cycle ,it is than stopped for 7 days during which time bleeding occurs
Mechanism of action:
They act by inhibiting the release of FSH & LH by anterior pituitary by negative feedback mechanism, preventing the development of graffian follicle ,ovulation & formation of corpus luteum is prevented
Increases viscosity of cervical mucus ,preventing the sperm penetration
Endometrial maturation is also altered preventing blastocyst implantation

10. Hormonal contraceptive(continued)
Injectable long acting prgestational preparation which can be given once in a three months
Sub dermal implants of progesterone have also been tried
Dermal patch , vaginal rings

11. Blockage of implantation
Intra Uterine Contraceptive Device(IUCD):
Are devices which are introduced & left inside the vagina for longer period of time .
They are of two types
Unmedicated devices as Lippe’s loop
Medicated devices as copper –T
They are usually changed after three years

12. Intra Uterine Contraceptive Device(IUCD)(continued)
Mechanism of action :
They produce local nonspecific inflammatory reaction in the endometrium & prevent implantation of blastocyst .
Copper increases cellular response & may alter the composition of cervical mucus
It is also believed that IUD increases the motility of fallopian tube ,so ovum reaches the uterus either before it is fertilized, or if fertilized before endmetrium is ready for implantation.
Recently hormone releasing IUCD’s have been devised .for e.g. progetasert releases progesterone which act locally on the endometrium & cervical mucus .

13. Intra Uterine Contraceptive Device(IUCD)(continued)
Side effects :
Bleeding
Abdominal pain / backache
Displacement
Perforation

14. Blockage of implantation (continued)
Post coital /morning after pill
it is used as emergency contraceptive measure after unprotected sexual intercourse( most effective within 72 hours )
It acts by preventing ovulation or cause premature degeneration of corpus luteum, thus preventing the implantation.
The WHO-recommended regimen for emergency contraception is: 1.5 mg of levonorgestrel as a single dose.

15. Future possibilities
Immunocontraception : in the testing stage is the vaccine that can induce formation of antibodies against human chorionic gonadotrophin
Male birth control pill: some scientist are seeking ways to manipulate the hormones to block the spermatogenesis
One interesting avenue is being explored to use the Ca blocking drugs ,as Ca is responsible for sperm motility

16. Average failure rates of common contraceptive techniques
Contraceptive method
Average failure rate (100 women-year)
Natural method
20-30
Chemical contraceptive 20
Barier method
10-15
OCP
2-2.5
IUCD 4

17. References Human physiology by Lauralee Sherwood, seventh edition
Current Obstetrics & Gynecology diagnosis & treatment