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In vitro fertilization (IVF) is a treatment option for women diagnosed with infertility, whether due to blocked or damaged Fallopian tubes, endometriosis, immunological infertility, cervical factor infertility, male factor infertility, or an unexplained cause. In vitro fertilization involves mixing egg cells with sperm cells in vitro - that is, in a laboratory rather than in the body. Once fertilization occurs, the embryos are transferred into the mother's uterus, creating a pregnancy that will be carried to term and delivered normally.
For a woman undergoing in vitro fertilization, each step of this process has been fine-tuned to increase her chance of pregnancy. The in vitro fertilization process involves four steps:
During in vitro fertilization, oocytes are retrieved from the patient and inseminated four to six hours later with sperm. After 16-20 hours, the oocytes are examined to see if fertilization has occurred. If it has, the embryo is cultured for an additional 48 to 96 hours and selected embryos are transferred to the patient's uterus during an embryo transfer procedure either on Day Three or Day Five after egg retrieval. During the transfer procedure, a small-bore catheter is passed through the cervical canal into the patient's uterus.
Mark D. Hornstein, MD, Division Director of Reproductive Endocrinology and Infertility at Brigham and Women’s Hospital, describes the indications for in vitro fertilization and how IVF is performed. Read the What You Need to Know about In Vitro Fertilization video transcript
Watch the In Vitro Fertilization Class video on what you need to know about IVF and other fertility treatments, including length of treatment, medications, laboratory tests, and procedures.
In vitro fertilization is the most effective therapy for patients who have been diagnosed with infertility. The treatment was originally designed for women with Fallopian tubes that are either blocked, severely damaged, or absent. In vitro fertilization is now also a therapy for patients with endometriosis, uterine factor infertility, anovulatory factor infertility and unexplained infertility.
In addition, IVF is an excellent choice for couples with mild to moderate male factor infertility. One of the advantages to selecting IVF is that fertilization of the egg can be identified, and embryo quality can be assessed in the IVF laboratory. Such assessment may provide insight regarding possible causes of infertility and the direction of any future treatment.
Many factors may influence a couple's chance for success, including the age of the woman, the couple's diagnosis, the quality of the sperm and the response of the woman's ovaries to medication. In addition, each phase of the in vitro fertilization cycle may or may not be successful. For example, if the ovaries have a poor response to medication, few or no eggs may develop resulting in cancellation of the cycle. There is also a small chance that fertilization may not occur due to either sperm and/or egg defects. Furthermore, eggs may be retrieved and embryos obtained, but the embryos may be of poor quality and lack the ability to develop. Finally, embryo transfer may be technically difficult or impossible (extremely rare). The most common reason for failure in an in vitro fertilization cycle is failure of the embryo(s) to implant within the uterus, usually associated with embryo quality issues.
Most patients want to know the chance of taking home a baby after their in vitro fertilization treatment. While this is an important statistic, it is also relevant to look at the number of pregnancies that involve triplets or more (high order multiple birth rate). Since these pregnancies involve risks to both the mother and the fetuses, IVF clinics strive to maximize pregnancy rates while minimizing the number of high order multiple pregnancies established. Therefore, when reviewing program statistics, the most important figures to assess are the percent of live-births per treatment cycle and the percentage of pregnancies with triplets or more.
We are a member of the Society for Assisted Reproductive Technology (SART and report our success rates to the Centers for Disease Control and Prevention (CDC) on an annual basis. View our SART statistics.
For couples with severe male factor infertility, in vitro fertilization with intracytoplasmic sperm injection (ICSI) provides the best chances for a successful outcome.
ICSI is performed in cases where the number of sperm available is extremely low or there is a past history of failed or poor fertilization. In this procedure, a single sperm is injected directly into the egg, thus helping to fertilize the egg.
Assisted hatching (AH) improves success rates for special populations. AH involves creating a hole in the covering around the embryo, known as the zona pellucida. This procedure is offered to older patients, those with repeat failed implantations, and/or those whose zonae appear thicker than normal. It is thought that by creating a hole in the zona, escapement from the covering is enhanced, and the normal implantation/attachment process is facilitated.
Special Treatment for Genetic and Inherited Disorders
PGT involves the removal of a few cells from an embryo on Day 5 or Day 6 and genetic analysis of the biopsied cell(s). The PGT procedure is offered to those couples at risk for having eggs with an abnormal number of chromosomes, or who have documented chromosome or single gene defects. Currently, PGT is offered for a multitude of genetic defects. Our patients meet with genetic counselors to discuss their own genetic issues and testing options.
Catherine Racowsky, PhD, HCLD, director of the IVF Laboratory at Brigham and Women’s Hospital, discusses the expertise of the IVF Laboratory team and the importance of high quality standards and a collaborative approach with physicians to help patients achieve their goal of a healthy pregnancy and baby.
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