What is In vitro fertilization IVF?
In vitro Fertilization IVF
In vitro fertilization (IVF) literally means fertilization of egg with sperm outside the body. During the process of IVF, the eggs are removed from the woman’s ovaries and fertilized with sperms in a laboratory (outside the body). The fertilized egg, called an embryo, is subsequently returned to the woman’s womb to grow and for development, before a baby is born. The excess of fertilized eggs, during the process of IVF, are then kept frozen inside Liquid Nitrogen for future use.
In a normal circumstance, an egg is fertilized via a sperm inside a woman’s body, at the fallopian tube. The fertilized egg (called embryo) will then travel through to the fallopian tube and reach the womb for implantation to occur. The embryo continues to nourish and nurture inside the womb. Usually baby is born about 9 months later, in a natural or unassisted conception.
Assisted Reproductive Technology (ART) comprises of various method to assist women in achieving pregnancy, who has difficulty trying to conceive. IVF is most often tried when other treatments have failed.
There are five basic steps to IVF:
Step 1: Ovarian Stimulation, also called super ovulation
• The ovaries are stimulated with fertility medications to induce multiple eggs recruitment, production and growth during In Vitro Fertilization (IVF) cycle.
• On average, women produce 10-12 eggs during an IVF cycle. Those eggs are located inside each sac (follicle) within the ovary itself.
• In comparison with regular menstrual cycle, only one egg reaches maturity and is released during the process of ovulation (fertile period), which is around mid-menstrual cycle.
• During Ovarian Stimulation, a woman will require 2-3 visits to the doctor for transvaginal ultrasounds, in order to assess and monitor the growing eggs inside the ovaries. Blood tests are usually required to assess the response to the stimulation as well.
• A trigger shot (usually Human Chorionic Gonadotropin Hormone) is given when the eggs have reached optimum sizes, to enhance maturity prior to egg harvest (Oocyte Pick Up).
Step 2: Egg retrieval
• Oocyte Pick- Up (OPU) is a brief procedure, usually performed under sedation, as Daycare Surgery.
• The aim of OPU is to remove the mature eggs from the woman’s ovaries at the end of Ovarian Stimulation, before ovulation take place.
• You will be given medicines for sedation and pain relief during the procedure. The whole process is usually taken care by our anaesthetist colleague.
• The procedure is usually performed through ultrasound guidance, a fine needle is inserted through the vagina into the ovary. Each sac (follicle), which contains eggs is aspirated, within the ovary. The fine needle is usually connected to a suction device, that creates a negative pressure resulting in pulling of the follicular fluid and eggs into a test tube during the collection. Each follicle is aspirated, one at a time.
• The procedure is subsequently repeated at the other ovary.
• There may be some cramping after the procedure, but it will go away within a day or two.
• In rare circumstances, the OPU is performed through laparoscopy (keyhole) surgery.
Step 3: Insemination and Fertilization
• The male partner’s sperms are pre-treated and selected for the process of insemination.
• The eggs are inseminated with sperms, placing it together through conventional method by placing 50,000 sperms: 1 egg ratio on a petri dish, under controlled environment.
• If the cause of infertility is due to severe male’s factor, each egg is injected with the partner’s sperm with fine needle under micromanipulation system, called Intra Cytoplasmic Sperm Injection (ICSI), to maximise the outcome of IVF.
• On the next day, the egg is checked for fertilization.
Step 4: Embryo culture
• When the egg is fertilized, the egg will start to divide. It is now known as an embryo.
• The embryologist (Laboratory scientist) will perform a schedule check on the embryo regularly, to ensure optimum growth of the embryos.
• The embryos are incubated further for another 2/3 day or 5/6 day, depending on the number of embryos, outcome of the IVF treatment and individual profile.
• A Day 5/6 embryo is renamed as Blastocyst, due to higher potential of pregnancy.
• Couples who have a high risk of passing a genetic (hereditary) disorder to offspring may consider Preimplantation Genetic Testing (PGT). The procedure is most often done at 5/6 days after fertilization (Blastocyst). It is a technique used to identify genetic defects in embryos
• When Preimplantation Genetic Testing (PGT) is required, the embryologist (Laboratory scientist) will incubate and culture the embryos to Blastocyst. Laboratory scientists remove few cells from each Blastocyst (which consists of 200 -300 cells) and screen the material for correct number of chromosomes and specific genetic disorders, under micromanipulation and laser assisted procedure.
• Embryo with normal genetic material is called Euploid Embryo, and has a higher chance for implantation inside the womb and a successful pregnancy.
• Euploid embryo optimise the chance of a successful pregnancy and shorten the time interval of getting pregnant with Embryo Transfer back to the womb.
• PGT also decreases the chance of passing a disorder to their offspring, miscarriage, and birth defects.
Step 5: Embryo Transfer
• Embryos are transferred back to the woman’s womb for implantation and pregnancy. This process is usually carried out 3 to 6 days after eggs’ retrieval and fertilization.
• It is a brief but a meticulous procedure without sedation, like doing a pap smear. Usually performed in a theatre (Embryo Transfer Room).
• The doctor will insert a small and tiny tube (catheter) containing the embryos into the woman’s reproductive tract under ultrasound guidance, through the vagina and cervix, and up into the womb cavity. The embryo(s) is gently released and deposited on the inner lining and proximal part of the womb.
• If an embryo(s) is implanted and grow in the cavity of the womb, it resulted in a pregnancy.
• More than one embryo may be placed into the womb at the same time, which can lead to twins, triplets, or more. The exact number of embryos transferred is a complex issue that depends on many factors, especially the woman’s age.
• The excess of embryos will be frozen for future use, in the event of after delivery or unsuccessful Embryo Transfer.