Apr 29, 2011

How In Vitro Fertilization Works

In vitro fertilization (IVF) is the joining of a woman’s egg and a man’s sperm in a laboratory dish. In vitro means “outside the body.” Fertilization means the sperm has attached to and entered the egg.

Normally, an egg and sperm are fertilized inside a woman’s body. If the fertilized egg attaches to the lining of the womb and continues to grow, a baby is born about 9 months later. This process is called natural or unassisted conception.
IVF is a form of assisted reproductive technology (ART). This means special medical techniques are used to help a woman become pregnant. IVF has been successfully used since 1978. It is most often tried when other, less expensive fertility techniques have failed.


       IVF  is  indicated  when  alternative  treatments  are  either  unlikely  to  achieve  pregnancy  or  have  failed  to  result  in  pregnancy.      
        If  you  have  blocked  fallopian  tubes  or  extensive  pelvic  adhesions  preventing  your  egg  from  entering  the  fallopian  tubes,  IVF  is  indicated.
        If  you  have  severe  endometriosis  and  are  unable  to  conceive  in  spite  of   one  or  more  operations,  IVF would  offer  a  better  chance  of  conception.
A human ovum with corona radiata surrounding it

        If  you  have  already  attempted  several  cycles  of  ovulation  induction  with  or  without  intra-uterine  insemination,  the  next  logical  step  is   to  move  on  to  IVF.
       If  your  husband’s  semen  shows  very  few  normal  moving  sperms,  too  few  to  be  able  to  fertilize  your  egg  in  the  normal  way  in  your  fallopian  tube,  IVF   ICSI  is  indicated.
        One  view  is  that  when  your  husband  has  sperms  that  are  less  than   5%   normal  forms,  less  than  5%  with  directional  movement  and  less  than  5  million  per  ml,  IVF  can  be  considered.

        If  your  husband  has  no  sperm  in  his  semen  but  has  live  sperm  in  his  testes or  epididymis,  these  can be  collected  by  a  Urologist,  stored  in  a  frozen  state  and  thawed  to  be  used  for  IVF  by  intra-cytoplasmic  sperm  injection  (ICSI ).

Factors to Consider

  • Age: Women younger than 35 years who do not have problems with their partners' sperm may try IVF.
  • Multiple births: Generally, in women who use IVF to establish a live birth, about 63% are single babies, 32% are twins, and 5% are triplets or more.
  • Cost: One cycle of IVF costs an average of  $12,000 - $17,000.
  • Reduced surgery: If a woman has IVF, she may not have to undergo surgery on her fallopian tubes. It is estimated that the IVF technique has reduced such surgeries by half.
  • Safety: Studies suggest that in vitro fertilization is safe. A recent study covered nearly 1,000 children conceived through these methods in 5 European countries and found that the children, monitored from birth to age 5 years, were as healthy as children conceived naturally. However, other studies have found a slightly increased risk of genetic disorders in children conceived through assisted reproductive technologies.


With in vitro fertilization, eggs are surgically aspirated from the woman's ovary under ultrasound guidance and mixed with sperm outside the body in a laboratory dish. After about 40 hours, the eggs are examined to see if they have become fertilized by the sperm and are dividing into cells. These fertilized eggs (now called embryos) are then placed in the women's uterus, thus bypassing the fallopian tubes where this process normally occurs.
IVF is now recognized worldwide as an established treatment for infertility.
This is how the procedure takes place:
  • The woman may be given certain drugs (hormones) to stimulate her ovaries to produce several eggs before the procedure to remove them.
  • A surgeon then inserts a needle through the vagina into the woman's ovary to remove eggs. This procedure used to be done with laparoscopic surgery, but the needle technique is much less invasive and much easier. General anesthesia is not required for this part of the procedure, but the woman may be given some sedating medication.
  • The fluid removed is examined in the laboratory to make sure eggs are present.
  • At the same time, the man provides a semen sample. He is asked not to have sexual intercourse for a few days before the eggs are retrieved from the woman and before he produces a semen sample (usually by masturbation). The sperm are separated from the semen in a laboratory procedure.
  • The active sperm are combined in the laboratory dish with the eggs. This may be referred to as in vitro fertilization.
  • About 18 hours after this fertilization procedure, it is possible to determine if the egg or eggs have been fertilized and have begun to grow as embryos. They are incubated and observed over the next 2-3 days or longer.
  • The doctor then transfers the embryos into the woman's uterus through the cervix with a catheter (a long slender tube). The woman should then remain in a resting position for the next hour or so.
  • She is given certain hormones for the next 2 weeks. If implantation works (the egg or eggs attach to the uterine wall and grow), the pregnancy test result is positive. 


  •     IVF requires a significant physical, emotional, financial, and time commitment. Stress and depression are common among couples dealing with infertility. A woman taking fertility medicines may have bloating, abdominal pain, mood swings, headaches, and other side effects. Many IVF medicines must be given by injection, often several times a day. (The health care team will teach the couple how to properly mix the medicines and give a shot.) Repeated injections can cause bruising.
  • In rare cases, fertility drugs may cause ovarian hyperstimulation syndrome (OHSS). This condition causes a build up of fluid in the abdomen and chest. Symptoms include abdominal pain, bloating, rapid weight gain (10 pounds within 3-5 days), decreased urination despite drinking plenty of fluids, nausea, vomiting, and shortness of breath. Mild cases can be treated with bed rest. More severe cases require draining of the fluid with a needle.
  • Medical studies to date have concluded that fertility drugs are not linked to ovarian cancer.
  • Risks of egg retrieval include reactions to anesthesia, bleeding, infection, and damage to structures surrounding the ovaries, including the bowel and bladder.
  • There is a risk of multiple pregnancies when more than one embryo is placed into the womb. Carrying more than one baby at a time increases the risk of premature birth and low birth weight. (However, even a single baby born after IVF is at higher risk for prematurity and low birth weight.) It is unclear whether IVF increases the risk of birth defects.

Outlook (Prognosis)

After embryo transfer, the woman may be told to rest for the remainder of the day. Complete bed rest is not necessary, unless there is an increased risk of OHSS. Most women return to normal activities the next day.
Women who undergo IVF must take daily shots or pills of the hormone progesterone for 8 - 10 weeks after the embryo transfer. Progesterone is a hormone produced naturally by the ovaries that helps thicken the lining of the womb (uterus). This makes it easier for the embryo to implant. Too little progesterone during the early weeks of pregnancy may result in a miscarriage.
About 12 -14 days after the embryo transfer, the woman will return to the clinic so that a pregnancy test can be done. (See: hCG quantitative test)
Call your health care provider right away if you had IVF and have:
  • A fever over 100.5 F (38 C)
  • Pelvic pain
  • Heavy bleeding from the vagina
  • Blood in the urine

Other assisted reproduction techniques

The following procedures have been used as alternatives to IVF but are not discussed in detail here:
  • Gamete intrafallopian transfer (GIFT): GIFT is similar to IVF. It is used when a woman has at least one normal Fallopian tube. Eggs are placed in this tube along with a man's sperm to fertilize there.
  • Zygote intrafallopian transfer (ZIFT): ZIFT is tubal embryo transfer in which a woman's eggs are taken from her ovaries, fertilized in the laboratory, and put back in the fallopian tubes rather than the uterus.
  • Assisted fertilization techniques when not enough sperm are available or sperm quality is not sufficient to fertilize include the following:
    • Partial zona dissection
    • Subzonal sperm injection
    • Intracytoplasmic sperm injection

  • Embryo cryopreservation (frozen fertilized egg and sperm)

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