in vitro fertilization

in vitro fertilization
MeshID	D005307

in vitro fertilization. It is a major assisted reproductive technology used to treat infertility, involving the manual combination of an oocyte and spermatozoon outside the body in a laboratory setting. The resulting embryo is then transferred to a uterus with the goal of establishing a successful pregnancy. The technique has revolutionized reproductive medicine since its first successful application in humans.

History

The foundational research for this process began in the late 19th century with the work of Walter Heape, who demonstrated embryo transfer in rabbits. Key milestones in the mid-20th century included the work of John Rock and Miriam Menkin, who first achieved fertilization of a human egg outside the body in 1944. The breakthrough clinical success came from the collaboration of British physiologist Robert Edwards and gynecologist Patrick Steptoe at Oldham General Hospital. Their work culminated in 1978 with the birth of Louise Brown, the first human conceived through this method, an event that garnered global attention through media outlets like BBC News. Edwards was later awarded the Nobel Prize in Physiology or Medicine in 2010 for his contributions. Early clinical practices were further developed at institutions like the Bourn Hall Clinic.

Medical uses

This technology is primarily indicated for various causes of infertility, including severe fallopian tube damage or blockage, disorders such as endometriosis, and male factor infertility including low sperm count or motility. It is also used for individuals with unexplained infertility and for those requiring third-party reproduction, such as using donor eggs or donor sperm. Furthermore, it is a critical component of preimplantation genetic testing for couples at risk of passing on genetic disorders, and it enables gestational surrogacy arrangements. Organizations like the American Society for Reproductive Medicine establish guidelines for its appropriate use.

Procedure

A typical cycle involves several coordinated steps. First, ovarian stimulation is achieved using injectable gonadotropin medications to produce multiple oocytes. Follicle development is monitored via transvaginal ultrasound and blood tests for hormones like estradiol. Oocyte retrieval is then performed under sedation using ultrasound-guided needle aspiration through the vagina. In the laboratory, retrieved eggs are combined with prepared sperm from a partner or a sperm bank; in cases of severe male factor infertility, a single sperm may be injected directly into an egg using a technique called intracytoplasmic sperm injection. Fertilized eggs are cultured for several days, often to the blastocyst stage, in incubators at facilities like the Cornell University Center for Reproductive Medicine. Finally, one or more embryos are selected for transfer into the uterine cavity using a thin catheter.

Ethical and religious considerations

The practice raises significant ethical debates, particularly regarding the moral status of embryos, which is a central concern for institutions like the Vatican and the Roman Catholic Church, which oppose the technology. The creation and potential disposal of surplus embryos, the use of preimplantation genetic diagnosis for non-medical sex selection, and concerns about commodification are major points of contention. Religious perspectives vary, with conservative branches of Judaism and Islam often providing more conditional acceptance under specific guidelines. High-profile cases, such as those involving the Rios embryos, have fueled international discourse on embryo disposition.

Success rates and risks

Success is influenced by factors such as maternal age, the cause of infertility, and the clinic's expertise, with data tracked by organizations like the Centers for Disease Control and Prevention in the United States and the Human Fertilisation and Embryology Authority in the United Kingdom. Potential risks include ovarian hyperstimulation syndrome, multiple pregnancies which carry risks like preterm birth, and possible slight increases in certain birth defects. There is ongoing research into long-term health outcomes for children born from these technologies, such as those coordinated by the Eunice Kennedy Shriver National Institute of Child Health and Human Development.

Legal status and regulation

The legal landscape varies dramatically by jurisdiction. In the United Kingdom, the Human Fertilisation and Embryology Act 1990 established a comprehensive regulatory framework overseen by the Human Fertilisation and Embryology Authority. In the United States, regulation is more fragmented, with guidelines from the Food and Drug Administration regarding tissue safety and voluntary reporting to the Society for Assisted Reproductive Technology. Countries like Italy and Germany have historically imposed restrictive laws, while others like Belgium and Spain have more permissive regimes. International disparities are evident in laws concerning compensation for donors, surrogacy agreements, and the use of embryos for stem cell research, as seen in debates following the Bush administration policies.

Category:Reproductive technology Category:Fertility medicine