Contraception
description
Transcript of Contraception
Lecture by Dr.Mohammed Sharique Ahmed Quadri
Assistant professor ,PhysiologyAl Maarefa College
Contraception
Is prevention of pregnancy before the implantation has taken place .
Methods of Contraception Blockage of sperm
transport to ovum1. Natural Methods
1. Rhythmic abstinence 2. Coitus interruptus
2. Barrier methods3. Use of spermicidal 4. Sterilization
a) tubal ligation b) vasectomy
Prevention of ovulation
1.Hormonal contraceptive (OCP)
Blockage of implantation
1.IUCD2.Emergency
contraception/morning after pill
Natural Methods of ContraceptionNatural methods
Rhythmic abstinenceCoitus 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
Natural Methods of ContraceptionBasal 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
Barrier methods: prevents entry of sperm into vagina or uterus
For males (condom)For females ( diaphragm or cervical cap )
Spermicidal: SuppositoriesGelFoam tabletscreams
Permanent Methods Female sterilization
( i.e tubal ligation or Tubectomy)
Male sterilization (vasectomy):
Prevention of ovulation Hormonal contraceptive
Oral contraceptives Combined pillsProgesterone only pillOnce a month pill
Injectable
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
Hormonal contraceptive(continued)
Injectable long acting prgestational preparation which can be given once in a three monthsSub dermal implants of progesterone have also
been tried Dermal patch , vaginal rings
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
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 .
Intra Uterine Contraceptive Device(IUCD)(continued)
Side effects :Bleeding Abdominal pain / backache Displacement Perforation
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.
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
Average failure rates of common contraceptive techniques
Contraceptive method Average failure rate (100 women-year)
Natural method 20-30Chemical contraceptive 20
Barier method 10-15OCP 2-2.5IUCD 4
References
Human physiology by Lauralee Sherwood, seventh edition
Current Obstetrics & Gynecology diagnosis & treatment
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