Help to make a babyTuesday, November 18 2008
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IVF is a medical procedure which unites egg and sperm in vitro (in the lab)....
THEY ONCE used to be known as test tube babies — children conceived in a lab for couples unable to achieve pregnancy through natural conception. Now known as in vitro fertilisation (IVF), what once seemed like a complex medical procedure available only to a privileged few has now become a treatment option for infertile couples in Trinidad and Tobago.
For more than a decade, IVF services have been offered locally through the Assisted Reproduction Clinic at Medical Associates in St Joseph, which has the record of achieving the Caribbean’s first IVF pregnancy in 1996.
Fertility treatments are also being offered by the Barbados Fertility Centre, one of the best known in the region, which is establishing facilities in TT.
At both facilities, couples are offered IVF, a medical procedure which unites egg and sperm in vitro (in the lab). Subsequently the embryos are transferred into the uterus through the cervix and pregnancy is allowed to begin. The process is usually done in conjunction with ovulation induction through drugs, monitoring of hormone levels and follicle scans with ultrasound.
The first successful IVF pregnancy in the world took place in 1978 with the birth of Louise Browne. The procedure was spearheaded by Drs Edwards and Steptoe who, after years of research and almost 100 attempts, achieved that historic first in utero conception and delivery of an in vitro baby.
In 1981 Howard and Georgianna Seegar Jones announced the delivery of the first IVF pregnancy in the United States. Instantly the Jones Institute at Eastern Virginia Medical School in Norfolk, Virginia, became an international centre for IVF. With the help of pioneers in Europe, Australia, and the United States, the number of centres grew and flourished.
Over the last two decades, the success rates for IVF have risen dramatically. Although it was first thought that the procedure would not exceed natural success rates of 15-20 percent, with lab improvements and culture media changes, the rates have increased to over 50 percent in women under 37.
The average couple will need three attempts before obtaining a pregnancy through IVF, all depending on their diagnosis. Some couples will have more than one cause of infertility making IVF the only realistic option for achieving pregnancy.
Some factors for using IVF include:
- Tubal problems where the woman’s fallopian tubes are blocked or damaged, which can make it difficult for the egg to be fertilised or for an embryo to travel to the uterus.
- Male factors such as low sperm count, problems with sperm function or motility which can inhibit sperm from fertilising an egg on its own.
- Severe endometriosis affecting both fertilisation of the egg and implantation of the embryo in the uterus.
- Ovarian issues which prevent the release or production of eggs.
- Abnormal uterus shape, fibroid tumours, or exposure to diethylstilbestrol (DES) as a foetus.
IVF treatment begins with ovulation induction, a type of medical therapy often performed alongside certain fertility treatments. Typically, medications that are used to help trigger the development of egg follicles are known as ovulation inducers. Ovulation induction often triggers the development of more than one egg.
Ovulation is induced to help women who cannot ovulate regularly produce an egg during their monthly cycle. Sometimes, inducing ovulation can allow two or three eggs to be released at once, therefore increasing chances of pregnancy.
There are four types of medication that can be used to help trigger ovulation.
Clomid, or clomiphene citrate, is one of the most well known ovulation inducers. It is a relatively inexpensive fertility medication which can usually be used with limited monitoring. Clomid is usually highly successful in inducing ovulation. Between 50 percent and 80 percent of women taking Clomid will begin to ovulate.
After ovulation a reproductive endocrinologist monitors the patient for ovulation. When an egg is released, the couple will engage in timed intercourse, in order to increase the chances of conception. Fertility treatments will also begin at this time. Another treatment option is injectable gonadotropins which contain FSH (follicle stimulating hormones). This helps to trigger the development of follicles inside of the ovaries, triggering ovulation. This type of fertility medication is more expensive then Clomid.
Gonadotropin is highly successful when it comes to inducing ovulation. More than 90 percent of women taking this drug begin to ovulate. Pregnancy rates per cycle are generally around 15 percent. However, there is a risk of multiple births, as well as developing hyperstimulation, in which the woman’s ovaries become enlarged, and the abdominal area becomes swollen with fluid.
Another type of ovulation induction uses a small pump to help deliver GnRH (gonadotropin releasing hormone) in small, sustained doses. GnRH can help to induce follicular development and ovulation in some women.
The next stage of the fertility treatment is egg retrieval which is the process where the woman’s eggs are removed from her ovaries. These eggs are later mixed with a man’s sperm to facilitate fertilisation. In order for egg retrieval to occur, a woman must first have follicle production stimulated by particular hormones. Once a number of follicles (potential eggs) are produced, fertility specialists can then remove these eggs from the ovaries in order to attempt fertilisation. If fertilisation is successful, the embryos will be placed back in to the woman’s uterus.
For IVF to be most effective, more than just one mature egg needs to be retrieved. The reproductive endocrinologist will attempt to remove all viable follicles that are present in the patient’s ovaries, so that multiple eggs can be fertilised. This means that a woman needs to have her follicles stimulated artificially.
Timing is extremely important when it comes to the IVF retrieval process. If the follicles develop too much, the egg inside will become too mature for efficient fertilisation. This can seriously affect the IVF process. For this reason, the patient’s ovaries will be monitored. This is typically done through ultrasound. When the follicles reach just the right maturity, egg retrieval can begin.
During the egg retrieval process, follicles from the woman’s left and right ovaries will be removed in a process known as follicular aspiration. This involves inserting a hollow needle through the top of the vagina and into the ovaries. This needle is then used to suction out any follicles that may be present in the ovaries.
After the egg retrieval, all viable eggs will be mixed with a sperm sample provided by the woman’s partner or sperm donor. These eggs will then be cultured overnight until they can be checked for fertilisation. If fertilisation occurs, the next stage of IVF treatment can begin: embryo transfer.
Immediately following IVF retrieval, any aspirated follicular fluid will be transported to the fertility clinic’s laboratory. Here, the patient’s follicular fluid will be examined under a microscope to identify all eggs that are present.
Each egg and its surrounding cells will then be washed in a special medium to remove any toxins and impurities. These eggs will then be transferred, in separate dishes, to a special incubator containing carbon dioxide. They will remain in this incubator until fertilisation is ready to take place, usually between two and six hours after egg retrieval, depending on the maturity of the eggs.
When the eggs are matured, they will each be combined with some of the man’s sperm, which will have been washed and divided up into specific amounts. Typically, no more than 100,000 sperm per millilitre are used during the fertilisation procedure. The sperm and egg will be combined in a dish that contains special culture medium. This culture medium, made up of protein, salt, and antibiotics, is designed to help the embryo during the first days of division. The dish is then placed back inside of the incubator. The developing embryos will be monitored carefully by an embryologist. After 18 hours of development, the embryologist will make the first check on your embryos. By this stage, the embryos will still be single cells. However, they will contain two clear bubbles (known as pronuclei) inside. These pronuclei are evidence that the embryo contains genetic material from both the woman and her male partner. Embryos without pronuclei are discarded. The embryos will then be left to develop for another 24 hours. At this point, embryos will be monitored for cell division. Most embryos have developed into two or four-cell embryos at this point. Some laboratories will allow embryos to continue culturing, while other labs will proceed with embryo transfer at this point.
Embryos that are cultured for two days are generally transferred at the two or four-cell stage. This type of transfer is beneficial for couples who have a low number of embryos available for transfer, or who have embryos that are developing poorly.
Embryo transfer is one of the most important parts of the IVF process. It is during this final stage of the IVF procedure that the embryos will be transferred into the uterus, in the hopes that the woman will become pregnant. Embryo transfer is completed after the eggs have been fertilised by the partner’s sperm and they have been through the embryo culture process. The procedure will be performed at a local fertility clinic.
It is vital that the embryo transfer procedure be performed by a skilled reproductive endocrinologist; if mistakes are made during the embryo transfer process, it can affect the patient’s chances of pregnancy. The greater the number of embryos transferred into the patient’s uterus, the higher the risk of a multiple pregnancy. When multiple pregnancies form, this can seriously affect the health of both mother and baby, so every effort to minimise multiple pregnancies must be taken by fertility clinics. In some countries, such as the UK, there is a limit of two embryos that can be transferred per IVF cycle.
The embryo transfer is a completely painless procedure. Once the embryos have been selected, they will be immersed in a fluid and stored in a special catheter. The patient is asked to lie down on an examination table and a speculum will be inserted into her vagina. The cervix is cleaned of any cervical mucus, which could interfere with the placement of the embryos and a flexible, rubber catheter is inserted. The catheter containing the embryos will then be placed inside of this rubber catheter. After the transfer procedure has taken place, the patient will be asked to lie down for two hours. After 48 hours the patient can resume normal activities In 12 days, the couple returns for a blood test to find out if the woman is pregnant.
Typically, most couples have leftover embryos remaining from the IVF process. There are a number of available options, including embryo cryopreservation and embryo donation. These options allow the couple to store their embryos for their own future use, or to help other couples who are suffering from infertility to conceive.
