However, another recent study suggests that it may pose risks later in pregnancy and should not always be recommended. Assisted hatching AH : A study in the Reproductive Biomedicine Online found that the process of assisted hatching — weakening the outer layer of the embryo before it is transferred to the uterus — does not improve pregnancy and implantation rates in women who are having fresh embryos transferred.
The researchers noted, however, that women having frozen embryos implanted do benefit from having their embryos treated in this way.
In many cases, only one fertilized embryo is transferred to the uterus, while other doctors believe that two fertilized embryos increase the chances of a successful pregnancy. In many cases, no more than two embryos will be used. For women under the age of 35 with an excellent chance of pregnancy, doctors will consider using just one embryo. A recent study posted in Fertility and Sterility showed that single embryo transfer in women less than 38 years of age reduces the risk of multiple births, yet does not seem to affect live birth rates.
This is important to note, as many doctors recommend using multiple embryos to ensure pregnancy. This research indicates that multiple embryos may not be necessary. According to a study posted in the International Journal of Reproductive Medicine , there is no statistical difference between using fresh and frozen embryos.
Embryo transfers using fresh embryos had a 23 percent pregnancy rate, whereas frozen embryos had an 18 percent pregnancy rate.
The study showed that frozen embryos could also be used for additional embryo transfers where fresh embryos could not. If the chance for pregnancy is low, doctors may consider freezing additional embryos for a second attempt at embryo transfer at a later date.
Individual success rates can vary and may depend upon the cause of infertility , ethnic backgrounds, and genetic disorders. The risks of embryo transfers themselves are very low. These risks are mostly related to increased hormonal stimulation, causing an increased risk such as a blood clot blocking a blood vessel. The woman can also experience bleeding, changes in her vaginal discharge, infections, and complications of anesthesia if it is used.
The risk of a miscarriage is about the same as in natural conception. Contact between the egg and sperm is random. Once the egg arrives at a specific portion of the tube, called the ampullar-isthmic junction, it rests for another 30 hours. Fertilization — sperm union with the egg — occurs in this portion of the tube. The fertilized egg then begins a rapid descent to the uterus. The period of rest in the tube appears to be necessary for full development of the fertilized egg and for the uterus to prepare to receive the egg.
Defects in the fallopian tube may impair transport and increase the risk of a tubal pregnancy, also called ectopic pregnancy. A membrane surrounding the egg, called the zona pellucida, has two major functions in fertilization. First, the zona pellucida contains sperm receptors that are specific for human sperm. Second, once penetrated by the sperm, the membrane becomes impermeable to penetration by other sperm.
Following penetration, a series of events set the stage for the first cell division. The single-cell embryo is called a zygote. Over the course of the next seven days, the human embryo undergoes multiple cell divisions in a process called mitosis. At the end of this transition period, the embryo becomes a mass of very organized cells, called a blastocyst. It's now believed that as women get older, this process of early embryo development is increasingly impaired due to diminishing egg quality.
Once the embryo reaches the blastocyst stage, approximately five to six days after fertilization, it hatches out of its zona pellucida and begins the process of implantation in the uterus. In nature, 50 percent of all fertilized eggs are lost before a woman's missed menses.
In the in vitro fertilization IVF process as well, an embryo may begin to develop but not make it to the blastocyst stage — the first stage at which those cells destined to become the fetus separate from those that will become the placenta.
The blastocyst may implant but not grow, or the blastocyst may grow but stop developing before the two week time at which a pregnancy can be detected. The receptivity of the uterus and the health of the embryo are important for the implantation process. UCSF Health medical specialists have reviewed this information. A reproductive endocrinologist closely monitors the cell multiplication over the next several days. In the case of a planned fresh embryo transfer, the eggs will then be transferred into an awaiting uterus on either day 3, 5, or 6 of external development.
In the case of a planned frozen embryo transfer, the embryos are typically frozen, thawed and transferred on day 5 of development.
In the meantime, the recipient of the embryo will be on a hormone therapy regimen that will cause their body to mirror where it would be in a non medicated cycle. This process allows doctors to create the ideal environment for the embryos to implant and grow before moving forward with the transfer. During the transfer, the doctor will migrate the embryo or embryos into the awaiting uterus, and at the conclusion of the transfer, the recipient is said to be 2 weeks plus the age of the embryo pregnant.
If a 5-day blastocyst was transferred, the recipient will walk out of the clinic 2 weeks and 5 days pregnant.
A pregnancy test, which will consist of a blood test, will generally be done days after the embryo transfer. If the result of the pregnancy test is positive, your surrogate will be somewhere between 4 weeks 3 days-5 weeks pregnant. Around the 10 week mark, your surrogate will be released to the care of an obstetrician and the pregnancy will follow the course of a traditional pregnancy.
Kim Bergman, PhD, a licensed psychologist of 26 years, has specialized in the area of gay and lesbian parenting, parenting by choice and third party assisted reproduction for over two decades. Bergman has created a comprehensive psychological screening, support and monitoring process for intended parents, surrogates and donors.
She is on the national Emeritus board of the Family Equality Council. Women who don't have a functional uterus or for whom pregnancy poses a serious health risk might choose IVF using another person to carry the pregnancy gestational carrier. In this case, the woman's eggs are fertilized with sperm, but the resulting embryos are placed in the gestational carrier's uterus. Ovarian hyperstimulation syndrome.
Use of injectable fertility drugs, such as human chorionic gonadotropin HCG , to induce ovulation can cause ovarian hyperstimulation syndrome, in which your ovaries become swollen and painful. Symptoms typically last a week and include mild abdominal pain, bloating, nausea, vomiting and diarrhea. If you become pregnant, however, your symptoms might last several weeks. Rarely, it's possible to develop a more severe form of ovarian hyperstimulation syndrome that can also cause rapid weight gain and shortness of breath.
A clinic's success rate depends on many factors. These include patients' ages and medical issues, as well as the clinic's treatment population and treatment approaches. Ask for detailed information about the costs associated with each step of the procedure. Before beginning a cycle of IVF using your own eggs and sperm, you and your partner will likely need various screenings, including:.
Before beginning a cycle of IVF , consider important questions, including:. How many embryos will be transferred? The number of embryos transferred is typically based on age and number of eggs retrieved. Since the rate of implantation is lower for older women, more embryos are usually transferred — except for women using donor eggs or genetically tested embryos.
Most doctors follow specific guidelines to prevent a higher order multiple pregnancy, such as triplets or more. In some countries, legislation limits the number of embryos that can be transferred. Make sure you and your doctor agree on the number of embryos that will be transferred before the transfer procedure. What will you do with any extra embryos? Extra embryos can be frozen and stored for future use for several years. Not all embryos will survive the freezing and thawing process, although most will.
Having frozen embryos can make future cycles of IVF less expensive and less invasive. Or, you might be able to donate unused frozen embryos to another couple or a research facility.
You might also choose to discard unused embryos. IVF involves several steps — ovarian stimulation, egg retrieval, sperm retrieval, fertilization and embryo transfer. One cycle of IVF can take about two to three weeks. More than one cycle may be needed. The start of an IVF cycle begins by using synthetic hormones to stimulate the ovaries to produce multiple eggs — rather than the single egg that typically develops each month.
Multiple eggs are needed because some eggs won't fertilize or develop normally after fertilization. Typically, you'll need one to two weeks of ovarian stimulation before your eggs are ready for retrieval. To determine when the eggs are ready for collection, you may have:. Sometimes IVF cycles need to be canceled before egg retrieval for one of these reasons:. If your cycle is canceled, your doctor might recommend changing medications or their doses to promote a better response during future IVF cycles.
Or you may be advised that you need an egg donor.
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