Embryo Transfer and Implantation
Embryo Transfer - The Final Stage of In Vitro Fertilization
Once the embryos have been created in the laboratory, they are placed into the uterus. At this point, in order for pregnancy to occur, an embryo must implant into the uterine lining. For many patients, the two-week wait between the embryo transfer procedure and the initial pregnancy test is the most difficult stage of the process. At our Florida IVF center, we believe that understanding in vitro fertilization and all of its components is key to coping with the stress that accompanies treatment.
While the embryos are developing in the laboratory, they are monitored for rate of growth, size, form, and signs of irregularity. Based on this data, the embryos are graded by quality, which helps us to estimate which are most likely to successfully implant and continue to develop. Typically, the embryos of the highest grade are selected for the first IVF transfer. Embryos with significant abnormalities are not suitable for transfer and will be discarded.
In most instances, no more than two or three embryos will be transferred during any given IVF cycle. This number allows the best chances for implantation while still keeping the risk of a multiple pregnancy to a minimum. In some cases, depending on age and other factors, our physicians recommend electing a single embryo transfer. Any additional embryos that are created will be cryopreserved for later transfer.
The embryo transfer procedure will be scheduled for three to five days after the egg retrieval. In IVF cycles where frozen embryos are to be used, the patient will be closely monitored via ultrasound and the embryos will be placed about two days after ovulation takes place.
This stage of in vitro fertilization treatment involves threading a thin catheter through the opening in the cervix, through which the embryos are gently deposited into the uterus. There is very little discomfort during this part of treatment and anesthesia is not necessary.
After the transfer procedure, our IVF patients are advised to take it easy for the next few days. Physical activity should be limited and strenuous exercise should be avoided. Although there is little that can be done at this point that will affect the chances of successful implantation, eating well, getting enough sleep, and minimizing stress will go a long way toward the health and wellbeing of the patient.
The process of implantation is complex and unpredictable. First, the embryo must escape, or hatch, from the zona pellucida. Even if the embryos are transferred on day three, this will not occur until after the embryos have reached the blastocyst stage on day five or six. Once an embryo has hatched, it must attach to the endometrium, or uterine lining, and gradually become imbedded in it. Once an embryo has completed this process, pregnancy is achieved and the in vitro fertilization cycle is a success.
Approximately fourteen days after the embryo transfer procedure, a blood test will be conducted to measure the amount of human chorionic gonadotropin (hCG) in the patient's system. This hormone is released only after implantation and is an accurate indicator of pregnancy. However, because hCG is sometimes used during the ovulation induction process to trigger the final maturation of the oocytes, small amounts may exist even if the patient is not pregnant. For this reason, at-home pregnancy tests that detect the presence of hCG but do not measure the quantity are not considered accurate for women undergoing in vitro fertilization. Elevated levels of hCG indicate that implantation has occurred and the patient is pregnant.
If pregnancy is detected, the patient will then undergo an ultrasound examination to confirm the findings, determine how many embryos have implanted, and ensure that everything is progressing normally.
If pregnancy has occurred, progesterone treatments will be continued for a period of time and then be gradually reduced as the patient's body takes over normal hormone production. The patient will continue to visit our south Florida IVF practice for blood work and ultrasounds during the early weeks of pregnancy to ensure that everything is proceeding as it should. Once we are able to detect the fetal heartbeat, the patient will be referred to an OB-GYN (if she does not have one already), who will handle the remainder of the patient's prenatal care. A high-risk obstetrician is only necessary if certain medical problems are a factor.
If pregnancy has not occurred, progesterone supplements will be ceased and the cycle will come to an end. If the couple has opted to try another in vitro fertilization cycle, we may recommend waiting one or even two complete menstrual cycles before resuming treatment. This allows the body to rest and gives us a chance to examine our treatment strategy and possibly change our approach in future cycles. In subsequent IVF cycles, the ovulation induction phase may not be necessary if frozen embryos are available for transfer.
Contact Our Southeast Florida IVF Center
Contact our IVF south Florida practice for more in vitro fertilization information or to schedule an IVF consultation.