In vitro fertilization (IVF) has been around since the birth of Louise Brown in 1978. This innovative form of assisted reproductive technology (ART) is a common medical procedure used today for treatment of infertility. The IVF process involves fertilization of an egg with sperm outside of the female body. For a normal birth, the resulting embryo is placed inside the woman’s uterus for development and delivery. Find out about the steps of IVF.
Step 1: Ovarian Stimulation with Fertility Medication
To stimulate the ovaries to produce many mature oocytes (eggs) rather than one single egg, fertility medications are used. Retrieval of multiple eggs will increase the chances of pregnancy since many embryos are available for selection. The medications used to increase egg production include:
Gonadotropins – These are synthetic forms of pituitary hormones, call follicle-stimulating hormone (FSH). These drugs stimulate growth of the follicles inside each ovary, which are needed to nourish eggs.
GnRH Analogues – To suppress production of FSH and luteinizing hormone (LH), which control menstrual cycle, GnRH analogues are used. These will also improve the quantity of eggs retrieved.
Human chorionic gonadotropin (hCG) – This is used at the end of a stimulation cycle for the purpose of inducing egg maturation. The egg retrieval process is timed to make sure the eggs are collected before ovulation occurs.
Step 2: Egg Retrieval
The egg retrieval process is done under conscious sedation. The doctor inserts a needle through the vaginal wall and into the ovary. Ultrasound guidance is used to located the follicle, and a suction device is used to collect the eggs. Egg retrieval takes around 30-60 minutes.
Step 3: Sperm Collection and Preparation
Sperm are collected for the IVF process before egg retrieval. The man must abstain from sex for around 4-5 days prior to the collection process. The semen is collected through masturbation at the fertility clinic in a private room. Because stress and pressure could inhibit the collection of the semen specimen, the specimen can be produced and frozen beforehand. The sperm will be prepared for insemination of the eggs in the laboratory setting.
Step 4: Insemination of Eggs and Embryo Development in the Laboratory
After eggs are retrieved, they are immediately transferred to the laboratory for evaluation and preparation for insemination. Many eggs are obtained from the follicular fluid, and all eggs are inseminated to provide a large selection of embryos for implantation. The sperm is concentrated so the hardiest are used. A sperm is added to each egg, and this incubates for two hours under strict controlled laboratory conditions.
Micro-injection of individual sperm into each egg is performed in a procedure called intracytoplasmic sperm injection (ICSI). In 24-48 hours, each egg must be analyzed for evidence of fertilization. The fertilized eggs continue to develop for a few days before being placed into the woman’s uterus. The woman takes progesterone before the embryos are transferred to prepare the uterus for implantation.
Step 5: Storage of Excess Eggs
Because it may take more than one IVF cycle to achieve pregnancy, the extra fertilized eggs or resulting embryos are frozen and stored using cryopreservation (freezing).
Step 6: Embryo Selection and Transfer
Embryo quality is a vital factor for the success of IVF. The best quality embryos are transferred to the uterus based on cell number and a complex grading system. Assisted hating may be used to increase implantation rates. This involves thinning or making a small hole in the zona pellucida (layer around the embryo) during the blastocyst stage.
Embryos are transferred to the uterus using a small catheter. This procedure does not involve anesthesia and is not painful. After embryos are placed in a small amount of fluid, they are put in the catheter, which is threaded through the cervix opening and into the uterus. To confirm placement, ultrasound guidance is used. The patient may chose to have more than one embryos transferred per treatment cycle, which increases the chances of pregnancy.