In vitro Fertilization: Now and Then
- Posted on: Jun 2 2014
Louise Brown, the first “test tube baby,” was born in July 1978 at the Oldham General Hospital, Greater Manchester, UK. This marked the first successful human birth through in vitro fertilization (IVF). IVF is a part of assisted reproductive technology which enables the fertilization of an egg by sperm in a laboratory dish. The fertilized embryo is later transferred to the receiving woman’s uterus to start a pregnancy.
The first human IVF success was closely followed by the birth of the second test tube baby, a girl named Durga, under the guidance of Kolkata-based physician and researcher, Subhash Mukhopadhyay. Today, more than 3 million babies have been born through IVF and assisted reproductive technologies.
The techniques of IVF have undergone significant changes to enhance the ease of the process and its success rates. The following improvements in IVF deserve special mention.
Ovarian Stimulation: Women are now administered fertility medications two weeks prior to egg retrieval. The treatment helps develop several follicles within the woman’s ovaries, leading to the generation of several mature eggs per cycle. Hormone therapies for ovarian stimulation comprise of oral medications, nasal sprays, transdermal patches, or injections. A careful selection of medications and optimal timing ensures successful ovarian stimulation with minimal risk to a woman.
Egg Retrieval: Previously, laparoscopy was used to retrieve mature eggs from a woman’s ovaries. These days, physicians monitor the development of mature eggs through ultrasound and blood tests. A transvaginal egg retrieval process is then employed to collect the eggs using ultrasound-guided needle aspiration. As a consequence, the risks associated with anesthesia for laparoscopy and high costs are avoided by the new egg retrieval technique.
Fertilization: Several mature eggs have to be placed in a laboratory dish and incubated with sperm, in order for fertilization to occur. The recent development of intracytoplasmic sperm injection (ICSI), wherein a single sperm is directly injected into an egg, has greatly improved fertilization rates. Moreover, ICSI is a necessity for low-motility, or low-count sperm.
Embryo Transfer: There are guidelines recommending the optimal number of fertilized embryos to be placed inside a woman’s uterus. Research has shown that factors, such as a woman’s age, number of IVF treatment cycles and embryo quality determine the success of implantation and pregnancy following embryo transfer. After egg fertilization and differentiation in the laboratory, an optimal number of embryos or blastocysts are implanted into a woman’s uterus. This process usually happens 2 – 3 days (for embryo transfer), or 5 – 6 days (for blastocyst transfer) after egg retrieval. The excess viable embryos are preserved through egg freezing techniques. The frozen eggs can be used later on by the same woman if the first IVF attempt fails.
Ethical Concerns: Although the birth of the first test tube baby led to heated ethical debates about these approaches to infertility, IVF is now accepted as a medical procedure throughout the world. To address the ethical concerns, well-defined regulations have been put in place. The success rates of IVF and other ART procedures continue to grow, and in the US today 1.5% of all births are from IVF procedures. With continued advancement in this field, newer ethical questions will come to light, and these matters need to be addressed by the society as a whole.
Before the inception of IVF, adoption was the only option for infertile couples to becoming parents. However, IVF enables couples to have their own biological children. Moreover, compared with the other assisted reproductive technologies, such as gamete intrafallopian transfer (GIFT) and zygote intrafallopian transfer (ZIFT), IVF has better success rates and is more widely accepted.
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