There are several steps involved in an IVF cycle, which typically involves 3 – 4 weeks of a woman’s time. This small amount of time may seem like a blip on the radar of our busy lives, but the amount of steps and information involved in just one cycle is overwhelming to digest – particularly when trying to explain to family and friends (and even to husbands or partners). Since I get asked about this process a lot, I wanted to dedicate a post to the breakdown of the IVF process step-by-step.*
Phase 1 – Ovarian Stimulation & Monitoring: This is also known as “stimming.” During this phase you will take a combination of injectable fertility hormones to stimulate follicles within the ovaries to produce multiple eggs. (A follicle is a fluid filled sac that usually contains an egg.) The medications will be self-administered at your home by subcutaneous injections (SubQ shots), which can be given in the lower abdomen below the belly button or upper thigh.
During this time, you will be monitored daily at your IVF clinic via vaginal ultrasound and blood work so that your Reproductive Endocrinologist (RE) may closely track your response to the medications. The ultrasound allows your RE to visibly observe how your follicles are growing and the blood work determines your rising levels of estrogen. Daily monitoring happens in the early morning (at my clinic it is between 7:00am – 8:30am) so that your results may be processed immediately. Your results are then reviewed by your RE, who will determine the next dosage of your daily meds. Each patient will then receive a call with these instructions (at my clinic the call is from a nurse in the afternoon). The patient then self-administers the medication that evening from the privacy of her home (at my clinic the designated time is between 7:00pm – 9:00pm).
It’s kind of amazing that all of this happens in just one day, from early morning until right before bedtime. It really gives me a great appreciation for all of the hard work and coordination that goes on at IVF clinics.
The duration of this part of the IVF cycle is dependent on your body’s natural response to the stimulation medication, but typically it lasts between 8 – 14 days.
Phase 2 – Trigger Shot: Once follicles reach a certain level of growth (typically between 16 – 18mm) and your estrogen levels have risen appropriately (typically over 1,000), your doctor will instruct you to take your “trigger shot.” This shot – known by the brand names of Novarel or Pregnyl – is comprised of human chorionic gonadotropin (HCG) and it officially begins the eggs’ release from the follicles. Unlike the other SubQ fertility injections, the trigger shot is an intramuscular (IM) shot that is administered on the upper, outer-most quadrant of the buttocks. Timing of your trigger shot injection is of critical importance as it is synchronized to be administered precisely 34-36-hours before your egg retrieval procedure.
Phase 3A – Egg Retrieval: This procedure is done precisely 34-36 hours after your trigger shot injection – exactly when the eggs are stimulated enough to be released, but before your body goes through actual ovulation. During egg retrieval, you’ll be sedated for comfort and safety. Eggs are retrieved via transvaginal ultrasound aspiration, and passed onto the laboratory where they will be prepared for fertilization.
Mature eggs are placed in a nutritive liquid (culture medium) and incubated. Not all eggs that are retrieved are mature.
The entire egg retrieval process takes between 15 – 30 minutes, but you will rest in the recovery room for approximately an hour following the procedure.
Phase 3B – Sperm Retrieval: If you’re using your partner’s sperm, he will provide a fresh semen sample on the day of your egg retrieval. It is critical that your partner arrives at the assigned time to ensure the sample is prepared to coincide with the egg retrieval. This means, that while you’re undergoing a sedated egg retrieval, your partner is providing his sperm sample.
Phase 4 – Fertilization via ICSI: Intracytoplasmic Sperm Injection (ICSI) isolates single healthy sperm in an andrology lab and then injects those sperm directly into each mature egg. Due to its extremely high success rates, our IVF clinic only uses the ICSI method of fertilization. However, regular insemination methods – where healthy sperm and mature eggs are mixed and incubated overnight – may also be used.
Phase 5 – Preimplantation Genetic Diagnosis & Screening: Embryos develop outside the body for five to six days in incubation until they reach “blastocyst stage.” A blastocyst is comprised of 200 to 300 cells. At this time, one cell can carefully be removed and tested for specific genetic diseases and the correct number of chromosomes (PGD/PGS testing). Embryos are frozen at this point while results of genetic screening are determined.
Fun Fact: The inner cell mass of a blastocyst is also a source of embryonic stem cells.
Phase 6 – Cryopreservation & Vitrification: Once embryos have reached blastocyst stage and have been biopsied for PGD/PGS testing, they are frozen (cryopreservation) via the vitrification technique (ultra-rapid freezing) and stored in an Embryology Lab. This process is done by placing the embryo into a solution and then rapidly freezing it in liquid nitrogen. The rapid freeze increases the cooling rate and prevents the formation of ice crystals, which may cause breakage later. Embryos frozen via vitrification have higher survival rates through the freeze and unfreeze process and their success rates are very similar to fresh embryo transfers.
Fun fact: The first reported pregnancy in humans from frozen embryos was in 1983 (source).
Phase 7 – Embryo Transfer: Embryos that have tested healthy via PGS/PGD screening can be transferred into the uterus. The embryo rated with the highest chances for pregnancy success is thawed on the day of transfer and placed in the women’s uterus via a simple non-surgical procedure. A pregnancy test is taken approximately nine days post transfer.
*IVF cycles and processes vary between clinics and patients treated. This breakdown reflects fertilization via ICSI, PGD/PGS testing, and a frozen embryo transfer (FET). This is very different than an IVF cycle with a live transfer.
**Sourcing: Mayo Clinic, Advanced Fertility Center of Chicago, CRM of Weil Cornel Medical College
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