- Books Name
- A TEXT OF BIOLOGY - CLASS XII
- Publication
- ACME SMART PUBLICATION
- Course
- CBSE Class 12
- Subject
- Biology
INFERTILITY
Infertility (L. in-not, fertilis-fruitful) is failure to conceive even after 1-2 years of regular unprotected sex.
The term is not synonym of sterility which means complete inability to produce offspring.
Infertility can best be defined as relative sterility.
It is of two types, primary and secondary.
Primary infertility is the infertility found in patients who have never conceived.
Secondary infertility is found in patients who have previously connceived.
Infertility is caused by defects found in males, females as well as both.
Infertility in Males
Semen of a fertile male is 2.5 to 5 ml per ejaculation with a sperm count of over 200-300 million, mostly motile, having proper fructose content and fluidity which is deposited high in the vagina.
Any defect in sperm count, sperm structure, sperm motility of seminal fluid leads of infertility.
Low sperm count is called oligospermia while near absence of sperms is known as azoospermia.
Low sperm motility is called asthenozoospermia while defective sperm morphology is termed as teratozoospermia.
Infertility in Females
A fertile woman is the one who regularly ovulates once every cycle, passes the egg down the reproductive tract which develops conditions for smooth passage of sperms and implantation of fertilised egg.
The various causes of infertility in females are as follows :
1. Anovulation (nonovulation) and oligoovulation (deficient ovulation).
2. Inadequate growth and functioning of corpus luteum.
3. The ovum is not liberated but remains trapped inside the follicle due to hyperprolactinaemia.
4. Fallopian tube may fail to pick up ovum.
5. Noncanalisation of uterus.
6. Defective uterine endometrium.
7. Fibroid uterus.
8. Defects in cervix.
9. Defective vaginal growth.
ASSISTED REPRODUCTIVE TECHNOLOGIES (ART)
More than two decades ago, in an experimental procedure called invitro fertilization (IVF), doctors joined a woman's egg and a man's sperm in a glass dish on the laboratory table.
For the first time, fertilization happened outside a woman's body. Nine months later, the first test-tube baby was born.
Today, assisted reproductive technology (ART) refers not only to IVF but also to several variations tailored to patient's unique conditions.
These procedures are usually paired with more conventional therapies, such as fertility drugs, to increase success rates.
Almost one out of every three cycles of ART results in the birth of a baby.
But ART procedures are invasive and expensive.
Though no long-term health effects have been linked to children born using ART procedures, most doctors recommend reserving ART as a last resort for having a baby.
Following is the list of important techniques which could benefit such infertile couples.
IVF & ET
In Vitro Fertilization (IVF) is the fertilization outside the body, in almost similar conditions as that in the body, which is followed by embryo transfer (ET). In this method, popularly known as, Test-Tube baby method, the ova from the wife/donor (female) and sperms from the husband/donor (male) are collected and are induced to form zygote under simulated conditions in the laboratory. The zygote or early embryos are then transferred into fallopian tube or uterus to complete its further development.
1. ZIFT
In ZIFT (Zygote Intra Fallopian Transfer) the zygote, formed in vitro, or early embryo up to 8-blastomere, is transferred into fallopian tube.
2. IUT
In IUT (Intra Uterine Transfer) the embryos with more than 8 blastomeres are transferred into the uterus for further development. The embryos formed by in-vivo fertilization can also be used for transfer to assist those females who cannot conceive.
3. GIFT
The GIFT (Gamete Intra Fallopian Transfer) is the transfer of an ovum collected from a donor into the fallopian tube of the recipient who can provide suitable environment for fertilization and further development.
4. ICSI
In ICSI (Intra Cytoplasmic Sperm Injection) is another specialized procedure to form an embryo in the laboratory in which a sperm is directly injected into the ovum.
5. AI
The AI (Artificial Insemination) is used for the cases of infertility which is either due to inability of the male partner to inseminate the female, or due to very low sperm counts in the ejaculate.
In this technique, the semen collected either from the husband or a healthy donor is artificially introduced either into the vagina or into the uterus (IUI -intra-uterine insemination) of the female.
ART requires extremely high precision handling by specialized professionals and expensive instrumentation. The infertility facilities are presently available only in very few centres in the country.
Obviously their benefits are affordable to only a limited number of people. Emotional, religious and social factors are also involved in the adoption of these methods.
Adoption
Our law also permits legal adoption. Adoption can benefit not only the people who are looking for parenthood but also to many orphaned and destitute children in India, who would probably not survive till maturity, unless taken care of.
Surrogacy or use of a gestational carrier: Another woman carries embryo or a donor embryo to term.
Concept Builder
Conventional Methods of Contraception: Rhythm method, spermicides, vaginal diaphragms and condoms.
Gossypol : It is a yellow pigment (C30H30O8) present in cotton seed taken orally (10-20 mg) daily for 3 months and thereafter twice weekly (20 mg) inhibits spermatogenesis.
Saheli : (Centchroman) is nonsteroidal drug taken orally twice a week for three months and then once a week is a potent contraceptive which prevents implantation but does not inhibit ovulation. It is a research product of Central Drug Research Institute, Lucknow.
IVE-ET — In vitro fertilisation and embryo transfer
GIFT — Gamete intra-fallopian transfer
ZIFT — Zygote intra-fallopian transfer
lUI — Intrauterine insemination
POST — Peritoneal oocyte and sperm transfer
SUZI — Subzonal insemination
ICSI — Intra-cytoplasmic sperm injection
TESE — Testicular sperm extraction
MESA — Microsurgical epididymal sperm aspiration