In-Vitro Fertilization (hereinafter referred to as “IVF”) is a procedure in which a woman’s ova (eggs) are fertilized outside of her body. One IVF treatment cycle takes approximately two to five weeks to complete. IVF can be a successful treatment for blocked or absent fallopian tubes, sperm abnormalities, endometriosis, problems with ovulation, egg donation, gestational surrogacy, or unexplained infertility.
During a normal menstrual cycle, usually only one egg is produced by a woman each month. In an IVF cycle, the chances of pregnancy are increased by stimulating the woman’s ovaries with medications so that several eggs, instead of only one, will develop. Once the eggs have matured, they are removed from the ovaries and fertilized by sperm in the IVF laboratory. After the eggs have been fertilized, one or more embryo(s) are placed into the woman’s uterus using ultrasound guidance so that they may implant and develop into a pregnancy. In cases where there are surplus embryos that are not transferred into the uterus, these may be cryopreserved (frozen) for use in a future treatment cycle, or for another child, thereby avoiding the need to repeatedly retrieve additional eggs. Embryos can be kept frozen indefinitely without any deterioration.
While the majority of IVF pregnancies result in single births, the risks of IVF include multiple pregnancy (twins, triplets, etc.), bleeding, infection and ovarian hyperstimulation syndrome.
Multiple pregnancy is associated with increased risks of prematurity, mortality, or long term disability, for some or all of the babies, and an increased risk of complications for the mother. One way you can minimize the risk of multiple births is by reducing the number of embryos transferred. Your physician will discuss the number they recommend transferring in your particular case. This number is individually based on factors such as age, embryo quality, and the number of previous failed attempts. We strongly discourage transferring more than one or two embryos in almost all patients. In most cases, single embryo transfer is recommended to reduce the risk of multiple births.
In about 1-3% of IVF patients, ovarian hyperstimulation syndrome (OHSS) may occur. When this happens, the woman’s ovaries become enlarged and fluid may accumulate in her abdomen. If it looks as though you will be at higher risk for this condition, you will be given instructions regarding changes in fluid, salt and protein intake for prevention. It may also be necessary to take medications for prevention and to minimize abdominal fluid accumulation and, if the condition occurs, to drain excess fluid from the abdomen on one or more occasions. You will be given more detailed instructions should this happen.
If a viable pregnancy is established, complications with this pregnancy may occur, as they may with any other pregnancy, including miscarriage, ectopic pregnancy and birth defects in the fetus.
During each IVF treatment cycle, transvaginal ultrasounds are performed to monitor the growth of the follicles (egg sacs) in the woman’s ovaries. Blood testing is undertaken to monitor the woman’s hormone levels. If necessary, the amount of medication being administered to stimulate the ovaries to develop eggs will be adjusted as the cycle progresses. When your eggs have neared maturity, you will be given an injection of HCG (human chorionic gonadotropin) to complete the maturation of your eggs. The HCG injection is given approximately 35-40 hours prior to your egg retrieval.
On the day of egg retrieval, a semen specimen is obtained from the male partner (or donor). The sperm are prepared and used to fertilize the eggs.
Prior to the procedure to retrieve the eggs, an intravenous (IV) is started. During the procedure local anesthetic may be used to freeze around the cervix and IV medications are generally used for sedation and pain relief. Your partner is able to be present with you during this procedure if you wish. Complications of local anesthesia and sedation, while very rare, include severe allergic reactions, respiratory depression and cardiac arrest.
Egg retrieval involves the physician passing a needle through the posterior (back) wall of the vagina, guided by ultrasound, into the ovaries. The fluid from each follicle is aspirated into a test tube. The eggs are microscopic (i.e. not visible to the naked eye) and are floating in the fluid. The sample is forwarded to the Embryologist who will locate the eggs in the fluid using a microscope. For various technical reasons, an egg is not always obtained from each follicle. The eggs that are retrieved are then combined with sperm, either by mixing them together in a dish, or by ICSI (intra-cytoplasmic sperm injection), or a combination, depending on the specific situation, and as recommended by your doctor. Some or all of the resulting embryos are transferred into the uterus after they have been allowed to grow in the laboratory for 3-6 days. There is a rare possibility that despite aspiration of fluid from each of the follicles that: no eggs will be retrieved; some or all of the retrieved eggs will not fertilize; and/or few or none of the fertilized eggs will develop into viable embryos.
As part of the process of In-Vitro Fertilization (IVF), embryos can be transferred into the woman’s uterus on day 3 following fertilization. At day 3 of development, the embryos consist of approximately 5 to 10 cells. It is sometimes difficult at the day 3 stage to determine which embryos are most likely to continue developing to the next stage, called the blastocyst stage (day 5 or 6). While many embryos appear to be developing normally under the microscope by 3 days following fertilization, some of them may arrest in development and do not develop further in the culture dish. On the other hand, embryos cultured outside the body are growing in an artificial environment and this also places a strain on them. Therefore prolonged in-vitro culture (outside the body) has potential advantages of better selectivity and reduction of multiple births by transferring less embryos, but at the same time the potential disadvantage of having to grow longer in an artificial environment. The main risk of prolonged in-vitro culture to the blastocyst stage is that none of the fertilized embryos may develop to that stage and there will be none to transfer. It is possible that some of these would have been successful inside the natural environment of the uterus. Around the world, approximately 70% of embryos are transferred at the day 3 stage and 30% at the day 5-6 stage. Your doctor will discuss their individualized recommendation as to what stage to grow your embryos (day 3 vs. day 5) for optimal outcome. This recommendation will often be made after the fact, once we see how many, and how well, the embryos are growing by day 2 or 3.
When the embryos are ready to be transferred, they are placed into a thin tube known as a catheter. Under ultrasound guidance, the catheter is inserted into the woman’s uterus and the embryo(s) are transferred. For this procedure you are required to have a full bladder. Following embryo transfer, the woman is generally prescribed progesterone by suppository or injections, and/or other medication(s) to help the embryos implant into the uterus.
After the embryo transfer, it is recommended that the woman avoid: stressful situations as much as possible; avoid anything that will significantly raise her body temperature (e.g. saunas, very hot baths, and high impact exercise); douching; and heavy lifting. Otherwise, she may resume normal activities after the embryo transfer.
About two weeks after embryo transfer, you will be instructed to return to the CReATe Fertility Centre to have a blood test to see whether you are pregnant. If the pregnancy test is positive, you should continue to take all medications until advised otherwise. If it is negative, you will be asked to see your doctor in follow-up to discuss next stages, such as transferring frozen embryos (if there are any), another fresh IVF cycle, or other options.
If you are pregnant, an ultrasound will be performed about 6½ weeks into the pregnancy (about 4½ weeks after the transfer) to confirm that one or more heart beats are present and that the fetus(es) is/are growing appropriately. If possible, the physicians at the CReATe Fertility Centre prefer to follow each pregnant patient during the first 3-4 months, in order to make sure the pregnancy gets off to a healthy start. Early testing for fetal abnormalities is available at CReATe. We can also help you at CReATe in the unfortunate event that you have a miscarriage.
During the first trimester, we will refer you to an Obstetrician, Family Physician or Midwife who we can recommend or to someone of your choice. They will continue to follow the rest of your pregnancy after you ‘graduate’ from CReATe. In some cases, if your pregnancy is felt to be high risk (such as a twin pregnancy) we will recommend an Obstetrician who specializes in high risk pregnancies.
If you have any further questions about IVF, or if you require clarification of any of the issues raised above, please speak with your physician.