All About IVF
WHAT IS IVF or THE TEST-TUBE BABY TECHNIQUE? Test-tube baby treatment is the popular name for in vitro fertilization, usually shortened to IVF. It is the process by which egg and sperm are mixed outside the body and then returned to the uterus after fertilization. It involves the removal of an egg from the woman’s ovary, the collection and purification of sperm from her partner, the mixing of sperm and egg in laboratory and, if fertilization occurs, the insertion of the developing fertilised egg – the embryo – into the uterus. The embryo, still quite invisible to the naked eye, is placed in its mother’s uterus usually two days after fertilisation, while it still consists of only a few cells and long before any organs have formed. WHEN SHOULD IVF BE CONSIDERED? The main situations when IVF may be worth considering are: * When the tubes are badly damaged and tubal surgery has less chance of success than IVF or in most cases where tubal surgery has already been unsuccessful. IVF should be considered because it bypasses the tubes.
* When the man’s sperm count is on the low side or abnormal, yet potentially capable of fertilizing an egg. Here IVF may be useful because fertilization can possible be manipulated and observed by the scientific team. This does not necessarily require sperm injection, or zona drilling, but simply very careful preparation of the sperm in suitable laboratory solutions.
* For certain women who have problems with the cervix perhaps ‘hostile’ mucus, IVF bypasses the cervix and its mucus.
* For women who are not ovulating spontaneously, but who produce eggs on fertility drugs without conceiving. In this situation, the ability to force the ovary to produce many eggs and then select the best ones for fertilization and transfer means that IVF may be suitable option.
* For some women with endometriosis or with very carefully investigated infertility which remains unexplained. We think that endometriosis is an excellent indication for IVF and have had particular success.
* For couples who have several factors together which are causing infertility; commonly a combination of poor male fertility and tubal disease are the most usual indications.
* Most recently, for certain couples who are at high risk of having genetically abnormal babies.
STAGES OF IVF TREATMENT:
1. TESTING A COUPLE’S SUITABILITY BEFORE TREATMENT
Preliminary preparation for an ART procedure may be as important as the procedure itself.
* Testing for ovarian reserve may be recommended in order to predict how the ovaries will respond to fertility medication.
* Blood Tests to assess the general health of the couple (ask the clinic for a complete list)
* Hysteroscopy to assess the inside of the uterus to look for problems like fibroids, polyps, or a septum may need to be corrected before IVF.
* Laparoscopy may be required to assess problems like endometriosis and to treat problems like hydrosalpinx; a fluid-filled, blocked fallopian tube which reduces IVF success should be removed prior to IVF.
* Semen analysis and culture
* Lifestyle issues should be addressed before ART. Smoking, for example, may lower a woman’s chance of success by as much as 50%. All medications, including over-the-counter supplements, should be reviewed since some may have detrimental effects. Alcohol and drugs may be harmful, and excessive caffeine consumption should be avoided. Some vitamins especially folic acid is started.
2. DOWN REGULATION
The process of stimulating the ovaries to produce eggs is a controlled one and requires that the body’s own internal capacity to regulate that growth be stopped. Otherwise the eggs may mature early and their collection may not be possible. For this purpose an injection is started usually in the previous cycle (D21) or sometimes even in the same cycle. At a particular time, (usually D2) blood levels of Estradiol (E2) and LH are tested to confirm the down regulation before starting stimulation.
3. OVARIAN STIMULATION
The best chance of successful pregnancy is obtained when more than one embryo is placed in the uterus at the same time. This is because so many early human embryos, normally fertilised, are lost or do not develop into babies. Consequently, one way of overcoming this natural loss is to put back several embryos simultaneously during IVF. During ovarian stimulation, also known as ovulation induction, ovulation drugs, or “fertility drugs,” are used to stimulate the ovaries to produce multiple eggs rather than the single egg that normally develops each month. Multiple eggs are needed because some eggs will not fertilize or develop normally after egg retrieval. Drug type and dosage vary depending on the program and the patient. Most often, ovulation drugs are given over a period of eight to 14 days. Ovulation drugs include clomiphene citrate, human menopausal gonadotrophins (hMG), follicle stimulating hormone (FSH), recombinant FSH and LH, and human chorionic gonadotrophin (hCG). Gonadotropin releasing hormone (GnRH) agonists or GnRH antagonists are used in conjunction with these medications to prevent premature ovulation.
4. ASSESSING THE DEVELOPMENT OF THE EGGS
Egg collection is generally timed to within a few hours of when the woman is expected to ovulate. If eggs are not collected very close to this time, they may not fertilise properly. This is the main reason why so many tests are often done to confirm the status of the woman’s hormones and, thus, development of her eggs.
* Hormone tests: As the follicle swells, the hormone oestrogen (Estradiol or E2) is produced in increasing amount. Regular blood test can detect this increase.
* Ultrasound: The swelling follicle can be directly measures using Trans vaginal ultrasound. This is usually done daily. We know from experience that, when the follicle is about 20 mm across, ovulation is imminent.
Using ultrasound examinations and blood testing, the physician can determine when the follicles are appropriate for egg retrieval. Generally, eight to 14 days of FSH and/or HMG injections are required.
5. Egg Retrieval
When the ovaries are ready, hCG or other medications are given. The hCG replaces the woman’s natural LH surge and helps the eggs to mature so they may be capable of being fertilized. The eggs are retrieved before ovulation occurs, usually 34 to 36 hours after the hCG injection is given. However, 10% to 20% of cycles are cancelled prior to the hCG injection.
Egg retrieval is usually accomplished by transvaginal ultrasound aspiration, a minor surgical procedure. Some form of anaesthesia is generally administered. An ultrasound probe is inserted into the vagina to identify the mature follicles, and a needle is guided through the vagina and into the follicles. The eggs are aspirated (removed) from the follicles through the needle connected to a suction device. The egg retrieval is usually completed within 30 minutes. Some women experience cramping on the day of the retrieval, but this sensation usually subsides by the next day. Feelings of fullness and/or pressure may last for several weeks following the procedure because the ovaries remain enlarged.
6. Insemination, Fertilization, and Embryo Culture
After the eggs are retrieved, they are examined in the laboratory The best quality, mature eggs are placed in IVF culture medium and transferred to an incubator to await fertilization by the sperm. Sperm, obtained by ejaculation or a special condom used during intercourse, are separated from the semen in a process known as sperm preparation. Motile sperm are then placed together with the eggs, in a process called insemination, and stored in an incubator. Fertilization occurs in the laboratory when the sperm cell penetrates the egg, usually within hours after insemination.
Visualization of two pronuclei the following day confirms fertilisation of the egg. One pronuclei is derived from the egg and one from the sperm. Approximately 40% to 70% of the mature eggs will fertilize after insemination or ICSI. Lower rates may occur if the sperm and/or egg quality are poor. Occasionally, fertilization does not occur at all. Two days after the egg retrieval, the fertilized egg has divided to become a 2-to 4-cell embryo. By the third day, the embryo will contain approximately six to 10 cells. By the fifth day, a fluid cavity forms in the embryo, and the placenta and foetal tissues begin to develop. An embryo at this stage is called a Blastocyst. If successful development continues in the uterus, the embryo hatches from the surrounding zona pellucida and implants into the lining of the uterus approximately six to 10 days after the egg retrieval. Embryo Transfer The next step in the IVF process is the embryo transfer. Embryos are usually transferred to the uterus on the 2nd or 3rd day after the egg retrieval. A short anaesthesia is given although not absolutely necessary. The physician identifies the cervix using a vaginal speculum. Two or three embryos suspended in a drop of culture medium are drawn into a transfer catheter, a long, thin sterile tube with a syringe on one end. The physician gently guides the tip of the transfer catheter through the cervix and places the fluid containing the embryos into the uterine cavity. The procedure is usually painless, although some women experience mild cramping.
Cryopreservation
Extra embryos remaining after the embryo transfer may be cryopreserved (frozen) for future transfer. Cryopreservation makes future ART cycles simpler, less expensive, and less invasive than the initial IVF cycle, since the woman does not require ovarian stimulation or egg retrieval. Once frozen, embryos may be stored for several years. However, not all embryos survive the freezing and thawing process, and the live birth rate is lower with cryopreserved embryo transfer. Couples should decide if they are going to cryopreserve extra embryos before undergoing IVF.
SUCCESS RATES
Currently the success rate per oocyte retrieval cycle is about 30%. Failures bring with it a lot of frustrations and depression but one must have faith as the cumulative success rates over 3-4 attempts is about 70%. The success rates depend on a lot of factors and especially the woman’s age. The live birth rate for each IVF cycle started is approximately 30% to 35% for women under age 35; 25% for women ages 35 to 37; 15% to 20% for women ages 38 to 40; and 6% to 10% for women over 40.
DONOR SPERM, EGGS, AND EMBRYOS
IVF may be done with a couple’s own eggs and sperm or with donor eggs, sperm, or embryos. A couple may choose to use a donor if there is a problem with their own sperm or eggs, or if they have a genetic disease that could be passed on to a child. Donors may be known or anonymous. In most cases, donor sperm is obtained from a sperm bank, and sperm donors undergo extensive medical and genetic screening. The sperm are frozen and quarantined for six months, the donor is tested for sexually transmitted diseases including the AIDS virus, and sperm are only released for use if all tests are negative. Overall, the use of frozen sperm rather than fresh sperm does not lower success rates.
Donor eggs are an option for women with a uterus who are unlikely or unable to conceive with their own eggs. Egg donors undergo the same medical and genetic screening as sperm donors, although it is not currently possible to freeze and quarantine eggs like sperm. The egg donor may be chosen by the infertile couple or the ART program. Egg donors selected by ART programs generally receive monetary compensation for their participation. Egg donation is more complex that sperm donation and is done as part of an IVF procedure. The egg donor must undergo ovarian stimulation and egg retrieval. During this time, the recipient (the woman who will receive the eggs after they are fertilised) receives hormone medications to prepare her uterus for pregnancy. After the retrieval, the donor’s eggs are fertilised by sperm from the recipient’s partner and transferred to the recipient’s uterus. The recipient will not be genetically related to the child, but she will carry the pregnancy and give birth. Egg donation is expensive because donor selection, screening, and treatment add additional costs to the IVF procedure. However, the relatively high live birth rate for egg donation, between 40% to 45%, provides many couples with their best chance for success. Overall, donor eggs are used in nearly 10% of all ART cycles.
In some cases, when both the man and woman are infertile, both donor sperm and eggs have been used. Donor embryos may also be used in these cases.
SURROGACY/GESTATIONAL CARRIER
A pregnancy may be carried by the egg donor (surrogate) or by another woman (gestational carrier). If the embryo is to be carried by a surrogate, pregnancy may be achieved through insemination alone or through ART. The surrogate will be biologically related to the child. If the embryo is to be carried by a gestational carrier, the eggs are removed from the infertile woman, fertilised with her partner’s sperm, and transferred into the gestational carrier’s uterus. The gestational carrier will not be genetically related to the child. All parties benefit from psychological and legal counselling before pursuing surrogacy or a gestational carrier.
RISKS OF ART
* Small risk of hyperstimulation. The stimulated cycle is very carefully monitored. However in any cycle there is a small risk of hyperstimulation which may result in enlargement of the ovaries. Most cases resolve with very simple treatment.
* Pregnancies involving Assisted Reproduction have higher miscarriage rates than normal.
* Removing eggs through an aspirating needle entails a slight risk of bleeding, infection, and damage to the bowel, bladder, or a blood vessel.
* The chance of multiple pregnancies is increased in all assisted reproductive technologies (about 30%) when more than one embryo is transferred. Some couples may consider multifetal pregnancy reduction to decrease the risks due to multiple pregnancies.
* First trimester bleeding may signal a possible miscarriage or ectopic pregnancy. Some evidence suggests that early bleeding is more common in women who undergo IVF and GIFT and is not associated with the same poor prognosis as it is in women who conceive spontaneously. Miscarriage occurs after ultrasound in nearly 15% of women younger than age 35, in 25% at age 40, and in 35% at age 42 after ART procedures. In addition, there is approximately a 5% chance of ectopic pregnancy with ART.
(Dr. Rajeev Agarwal is a Gynaecologist with a Special Interest and Training in Infertility. He obtained his MD from Kasturba Medical College and trained further at the Manipal Assisted Reproduction Centre. He has received various awards during his training and further received the prestigious Kumud Tamaskar Award for his research work on Polycystic Ovarian Syndrome. He has various papers and lectures to his credit. He received further training und)