Test Tube Baby : In Vitro Fertilization & GIFT
Learn about Test Tube Babies by In Vitro Fertilization & GIFT procedures. Read - how to have a baby by an Infertility specialist who runs a fertility center in India.From the book
How to Have a Baby: Overcoming Infertilityby Dr. Aniruddha Malpani, MD and Dr. Anjali Malpani, MD.
What are the assisted reproductive technologies (ARTs) ?
What tests need to be done prior to doing IVF treatment ?
What are the 5 basic steps of an IVF treatment cycle ?
How is superovulation performed ?
How is superovulation monitored ?
When may an IVF cycle be cancelled ?
Fig 1. World's first test tube baby
The birth of Louise Brown through in vitro fertilization (Fertilization Video) (IVF) in 1978 was a major milestone in infertility treatment. It dramatically changed the treatment options for infertile couples, and techniques for assisted reproduction have evolved rapidly since then. In a short span of 20 years, In Vitro Fertilization has become the cornerstone of reproductive medicine, and In Vitro Fertilization clinics today routinely perform techniques which were thought to belong to the realm of science fiction a generation ago!
This chapter will help you understand assisted reproductive technologies (ART) such as In Vitro Fertilization and Gamete Intra-fallopian Transfer (GIFT) that are now standard medical treatments for infertility. A few years ago, these techniques were used as methods of last resort, when everything else which had been tried had failed. Today, specialists will often resort to these techniques first, since they offer such excellent results, rather than waste the patient's time and money with the traditional ineffective options. Today, thanks to In Vitro Fertilization technology, there is practically no infertile couple who cannot be offered treatment. However, as with all technology, you need to understand exactly how it works, and when it should be used.
IVF - In Vitro Fertilization
In Vitro Fertilization is the basic assisted reproduction technique, in which fertilization occurs in vitro (literally, in glass). The man's sperm and the woman's egg are combined in a laboratory dish, and after fertilization, the resulting embryo is then transferred to the woman's uterus. The five basic steps in an IVF treatment cycle are superovulation (stimulating the development of more than one egg in a cycle), egg retrieval, fertilization , embryo culture, and embryo transfer.
In Vitro Fertilization is a treatment option for couples with various types of infertility, since it allows the doctor to perform in the laboratory what is not happening in the bedroom - we no longer have to leave everything up to chance! Initially, In Vitro Fertilization was only used when the woman had blocked, damaged, or absent fallopian tubes (tubal factor infertility). Today, In Vitro Fertilization is used to circumvent infertility caused by practically any problem, including endometriosis; immunological problems; unexplained infertility; and male factor infertility. It is a final common pathway, since it allows the doctor to bypass nature's hurdles, and overcome its inefficiency, so that we can give Nature a helping hand!
Tests prior to In Vitro Fertilization
In order to perform In Vitro Fertilization, only 3 things are required - eggs, sperms and a uterus, and before starting the In Vitro Fertilization cycle, the doctor will check these.
First, a sperm survival test is carried out. This is a "trial" sperm wash, using exactly the same method as will be actually used in In Vitro Fertilization, to assess whether an adequate numbers of sperms can be recovered in order to do In Vitro Fertilization. This test will also help the laboratory to decide which method of sperm processing should be used during In Vitro Fertilization.
A blood FSH level will provide an idea of the "ovarian reserve", and provide information on whether or not the woman will produce enough eggs after superovulation. For older women, some clinics do a clomiphene citrate challenge test. If the level is very high, this suggests early ovarian failure, and it may be a better idea to consider donor eggs.
Many clinics may do a hysteroscopy, in order to assess that the uterine cavity is totally normal. They may also do a "dummy" embryo transfer to make sure there are no technical problems with this procedure. Some clinics also do a cervical swab test, to rule out the presence of infection in the cervix.
If a woman has blocked fallopian tubes with large hydrosalpinges, some clinics will remove these prior to the In Vitro Fertilization cycle, because they feel that the presence of a hydrosalpinx decreases pregnancy rates after In Vitro Fertilization.
For men who have difficulty in producing a semen sample " on demand", the clinic may also freeze and store the sample prior to treatment, as a backup. This can help to prevent the tragedy of having to abort an entire treatment cycle because the man could not produce a semen sample when needed.
Fig 2. Blood being drawn for testing
Blood tests which may be done include tests for immunity to rubella; and tests for Hepatitis B, and AIDS. Most doctors will also advise patients to start taking folic acid, as part of prepregnancy care, as this helps to reduce the risk of certain birth defects.Patients who stand a very poor chance of success with In Vitro Fertilization include the following :
- Older women, whose ovaries are failing. However, there is no upper age limit at which In Vitro Fertilization should not be done,- and in fact, for older women, it might represent their only chance of success. It's not really the age of the woman which is the limiting factor - it's the quality of her eggs.
- Men whose sperm count is very low. Most clinics will consider doing In Vitro Fertilization only for men with at least 3 million motile sperm in the ejaculate. If the sperm counts are lower than this, then ICSI (or microinjection) is a better option.
- Women with a damaged uterus (for example, because of healed tuberculosis) because the chance of successful implantation of the embryo in the uterus becomes very poor.
- It is also not advisable to go in for In Vitro Fertilization treatment without trying simpler treatment options first. In Vitro Fertilization is a complex procedure involving considerable personal and financial commitment, so other treatments are usually recommended first.
- Egg retrieval
- Embryo culture
- Embryo transfer
The Basic Steps of IVF- In Vitro Fertilization
Superovulation or Ovulation Enhancement
During superovulation, drugs are used to induce the patient's ovaries to grow several mature eggs rather than the single egg that normally develops each month. This is done because the chances for pregnancy are better if more than one egg is fertilized and transferred to the uterus in a treatment cycle. Depending on the program and the patient, drug type and dosage varies. Most often, the drugs are given over a period of nine to twelve days. Drugs currently in use include : Human Menopausal Gonadotropin (HMG), Follicle Stimulating Hormone (FSH), Human Chorionic Gonadotropin (HCG) and gonodotropin releasing hormone (GnRH) analog.
Today, most In Vitro Fertilization programs use GnRH analogs (such as Lupron or Buserelin) in combination with gonadotropins during ovulation enhancement. Treatment with the analogs prevents the release of FSH and LH from the pituitary gland during treatment
("pituitary downregulation") and thereby prevents premature ovulation. This therefore gives the doctor much more control over the superovulation phase, because we can then grow eggs to suit our convenience, as we have taken over control of the cycle. Patients are often confused as to why we need to suppress the pituitary hormones when we are trying to grow lots of eggs. Remember that the GnRH analogs suppress the pituitary, and have no direct effect on the ovary, so that they do not suppress egg production. GnRH analogs can be used either in the form of a long protocol (when they are started from Day 21 of the previous cycle); or as a short protocol (when they are started from Day 1 of the cycle).
Fig 3. GnRH antagonist used for downregulation
Another option is to use the newer GnRH antagonists (such as Antagon or Cetroride), which can selectively suppress the LH surge, and it is hoped that these may provide better control. However, the pregnancy rates with these are no better.
An ultrasound scan is done on Day 3, to confirm that there are no cysts in the ovary, and that downregulation has been achieved. A blood test for estradiol can also be done, to ensure that the ovaries are quiescent and downregulated, and the result should be less than 50 pg/ml. The HMG injections for superovulation are then started from Day 3. The dose of HMG used needs to be individualized for each patient., and depends upon the antral follicle count and ovarian morphology. Our standard dose is 225 IU daily for patients less than 35; 300 IU daily for patients more than 35; 450 IU daily for poor responders; and 150 IU daily for patients with PCOD.
Timing is crucial in an In Vitro Fertilization treatment cycle, in order that the doctor recover mature eggs. To monitor egg production, the ovaries are scanned frequently with vaginal ultrasound, usually on a daily or alternate day basis from Day 10 onwards. Blood samples are also drawn in some clinics, to measure the serum levels of estrogen, and sometimes luteinizing hormone (LH). While some clinics do this on a daily basis, we feel this is very unkind to the patient, who often ends up feeling like a pincushion! For most patients, the ultrasound scan provides enough information, and it is very rarely that we need to do blood tests for our patients - we try to be kind! The dose of the HMG is adjusted, depending upon the ovarian response.
Fig 4. Ultrasound scan of an ovary during superovulation. There are more than 6 follicles in this image. All the follicles are growing well. It is likely the doctor will be able to retrieve one egg from each of these follicles during egg retrieval
By interpreting the results of the ultrasound, we can determine the best time to harvest or remove the eggs.
Fig 5. Ultrasound scan of the uterus during an IVF cycle. The central endometrial stripe is thick and trilaminar, suggesting that the uterus has responded well and is ready for embryo implantation
Follicles usually grow at a rate of 1-2 mm/day, and a mature follicle has a diameter of about 16-20 mm in size. Thus, if a patient has about 10 follicles on ultrasound, of which the largest is more than 18 mm, we know that the follicles are mature and the eggs are ready for retrieval. The endometrium should also be examined carefully on the vaginal scan, and this should be thick (more than 7 mm, and have a triple texture). Some clinics also measure the blood estradiol level, to provide additional information, and each mature follicle produces about 200-300 pg/ml of estrogen. When the follicles are mature, we prescribe an injection of human chorionic gonadotropin (HCG) to trigger ovulation. The use of HCG allows us to control when ovulation will take place - and this is 36 to 39 hours after the HCG injection. This precise control allows the In Vitro Fertilization team to be prepared to harvest eggs just before that time. The HCG simulates the woman's natural LH surge, which normally triggers ovulation.
This is what a typical In Vitro Fertilization treatment protocol in our clinic looks like. Treatment starts from Day 1 (the day the bleeding starts) of the cycle. At this time, we downregulate by starting Inj Buserelin (Suprefact, GnRH analog mfr by Hoechst), 0.5 ml sc daily. On Day 3, we do an ultrasound scan to confirm there is no ovarian cyst, after which we start superovulation with 3 ampoules (225 IU) of HMG (Menogon) daily. The dose of HMG will
depend upon the ovarian morphology and the antral follicle count.
We do the next scan on Day 10, after which we do scans every alternate day, to monitor follicular growth.
This is what the daily schedule would look like.
Day 1. Inj Buserelin, 0.5 ml sc. (Downregulation starts)
Day 2. Inj Buserelin, 0.5 ml sc.
Day 3. Inj Buserelin, 0.5 ml sc. Vaginal ultrasound scan to confirm there is no ovarian cyst. If there is no cyst, we can commence superovulation. If there is a cyst larger than 30 mm, we can aspirate it and continue with treatment.
Day 4 Inj Buserelin, 0.5 ml sc. Inj Menogon (75 IU), 3 amp IM. Superovulation starts.
Day 5 Inj Buserelin, 0.5 ml sc. Inj Menogon (75 IU), 3 amp IM
Day 6 Inj Buserelin, 0.5 ml sc. Inj Menogon (75 IU), 3 amp IM
Day 7 Inj Buserelin, 0.5 ml sc. Inj Menogon (75 IU), 3 amp IM
Day 8 Inj Buserelin, 0.5 ml sc. Inj Menogon (75 IU), 3 amp IM
Day 9 Inj Buserelin, 0.5 ml sc. Inj Menogon (75 IU), 3 amp IM
Day 10. Inj Buserelin, 0.5 ml sc. Inj Menogon (75 IU),3 amp IM.
Fig 6. Ultrasound scan of an ovary during superovulation. This shows how we measure each follicle. A mature follicle is about 18 mm in size.
Vaginal ultrasound scan to monitor follicular growth
The Buserelin and Menogon injections will continue on a daily basis; and scans will be performed every alternate day, until the follicles are mature. This is usually Day 14- Day 16 for most patients. At this time, an HCG injection will be given, and eggs retrieved 36 hours after this.
With older forms of superovulation regimes using clomiphene and HMG, the treatment cycle was cancelled in roughly one quarter of the IVF cycles. One of the reasons for this was that some of these women had a premature, spontaneously occurring LH surge with resulting premature spontaneous ovulation. When this happened, the follicles ruptured prior to egg collection, and the eggs were lost in the pelvic cavity, as a result of which they could not be retrieved. While spontaneous LH surges are very rare with the use of GnRH analogs, we still need to cancel cycles in about 10 % of patients.
The commonest reason for canceling a cycle today is a poor ovarian response. If patients grow less than three follicles, and if the estradiol level is low, the chances of a pregnancy are poor, and patients may decide to abandon the cycle. The problem of a poor ovarian response is commoner in older women and in women with elevated FSH levels, and these can be difficult patients to treat! Patients who have a poor ovarian response during In Vitro Fertilization treatment are often very upset, because this is not something they (especially if they are young) are mentally prepared for. Most young women expect to grow a lot of eggs, and are shattered when they don't do so. However, remember that this is not the end of the road - it simply means that the superovulation regime will need to be modified for the next treatment cycle. The doctor may need to increase the dose of HMG in order to grow more follicles, and this is often helpful for young women.
The other reason to cancel a cycle is when patients grow too many follicles! These are usually patients with PCOD; and if there are more than 25 follicles, or if the level of the estradiol is more than 6000 pg/ml, many clinics will cancel the cycle, because the risk of ovarian hyperstimulation syndrome (OHSS) is very high. An alternative option is to go ahead with egg collection, and freeze all the embryos. This allows the doctor to salvage the cycle; and if the embryos are not transferred, the risk of OHSS is reduced. The frozen embryos can then be transferred later, giving the patient a good chance of achieving a pregnancy.
In our clinic, however, we do not need to cancel these cycles. This is because we use a special technique during egg collection with a double lumen needle, which allows us to remove all the granulosa cells from each follicle at the time of egg retrieval, by flushing each follicle meticulously. Since these cells are the ones responsible for producing the chemicals which cause OHSS, by removing them we reduce the risk of our patients getting OHSS dramatically!