In Vitro Fertilization (IVF) is an assisted reproductive technology (ART) where eggs are retrieved from the ovaries and fertilized by sperm in a laboratory setting. “In vitro” literally means “in glass,” a reference to the glass petri dishes originally used. Once fertilized, the egg becomes an embryo, which is cultured for several days before being transferred into the uterus.
For many, IVF is the final stop on a long, emotional road of infertility. It can feel overwhelming, a maze of medical acronyms, hormone injections, and high stakes. But knowledge is the antidote to anxiety.
This comprehensive guide pulls back the curtain on the IVF process, explaining exactly what happens in your body, in the lab, and during the procedure, so you can approach your cycle with confidence.
Key Takeaways
- Complete Timeline: From the start of medications to the pregnancy test, an IVF cycle typically spans 6 to 8 weeks (including preparation).
- Success Factors: Age is the single biggest predictor of success, but Preimplantation Genetic Testing (PGT-A) can equalize outcomes for older patients by selecting chromosomally normal embryos.
- The “Black Box”: The 5–7 days your embryos spend in the lab are critical. We use advanced incubators to mimic the human body, allowing embryos to reach the “blastocyst” stage.
- Pain Management: The egg retrieval is performed under sedation when you sleep through it. Most discomfort comes from bloating before the procedure, not pain during it.
Phase 0: The Preparation (Testing & Priming)
Before a single injection is given, there is a crucial preparatory phase. You cannot build a house without a blueprint, and we cannot start IVF without a clear map of your fertility.
Diagnostic Testing
Your doctor needs to know three things:
- Ovarian Reserve: How many eggs do you have left? We measure this via AMH (Anti-Mullerian Hormone) levels and an Antral Follicle Count (ultrasound).
- Uterine Health: Is the “home” ready for the baby? We often perform a saline sonogram or hysteroscopy to ensure there are no polyps or fibroids inside the uterine cavity that could block implantation.
- Sperm Quality: A comprehensive semen analysis checks not just count, but motility (movement) and morphology (shape).
The “Priming” Month
Many patients are surprised to learn they might be put on birth control pills for 2–3 weeks before starting IVF.
- Why birth control? It quiets the ovaries and prevents cysts. Most importantly, it synchronizes your follicles so they all start growing at the same starting line when stimulation begins. This helps us retrieve a “cohort” of eggs rather than just one dominant one.
Phase 1: Ovarian Stimulation (Days 1–12)
In a natural cycle, your brain sends a signal to your ovaries to grow one egg. In IVF, we want to override that signal to recruit multiple eggs (ideally 10–15, though this varies widely).
The Medications
You will self-administer injectable hormones for approximately 10 to 12 days.
- FSH (Follicle Stimulating Hormone): (Brand names like Gonal-F or Follistim). This is the gas pedal. It tells your ovaries to produce as many follicles as possible.
- Menotropins: (Brand names like Menopur). A mix of FSH and LH to support egg quality and growth.
- GnRH Antagonist: (Brand names like Cetrotide or Ganirelix). This is the brake. Added halfway through the cycle, it prevents your body from ovulating the eggs too early before we can retrieve them.
Field Insight: “The biggest fear patients have is the injections. In reality, the needles used for stimulation are subcutaneous, meaning they go into the fatty tissue of the stomach, not the muscle. They are very thin, similar to insulin pens. We tell patients to ice the area for 5 minutes beforehand; most feel nothing more than a quick pinch.” Head Fertility Nurse, American Reproductive Centers.
Monitoring Appointments
During this phase, you are “married” to the clinic. You will come in every 2–3 days for:
- Transvaginal Ultrasounds: To measure the size of your follicles (fluid-filled sacs that contain eggs). We want to see them growing evenly, around 1-2mm per day.
- Blood Work: To measure Estradiol (Estrogen). As follicles grow, they secrete estrogen. If levels get too high too fast, we adjust your medication dose down to ensure safety.
Phase 2: The Trigger Shot (Day 12-14)
Once your lead follicles reach approximately 18mm–20mm in size, it is time for the most critical step: The Trigger Shot.
This injection (usually HCG or Lupron) mimics the body’s natural LH surge. It performs the final maturation of the eggs, peeling them away from the follicle wall so they float free for retrieval.
- Timing is Critical: This shot must be taken at the exact time instructed (e.g., 9:30 PM sharp). The retrieval is scheduled precisely 35–36 hours later. If you take it late or early, you risk losing the eggs.
Phase 3: Egg Retrieval (The Procedure)
This is the day the eggs leave your body.
- Anesthesia: You will be placed under Mac (Monitored Anesthesia Care) or “twilight sedation.” You breathe on your own, but you are completely asleep and unaware. You will feel no pain.
- The Technique: Using ultrasound guidance, the doctor inserts a thin needle through the vaginal wall directly into the ovaries. The needle enters each follicle and uses gentle suction to aspirate the fluid and the egg inside.
- Duration: The surgery takes only 15–20 minutes.
- Recovery: You wake up in the recovery room about 30 minutes later. You may feel groggy and have some cramping (like a heavy period). You need a ride home and should plan to rest for the remainder of the day.
Phase 4: The Laboratory (Fertilization & Culture)
While you go home to recover, the relay race passes to the embryology team. This happens in our high-tech, sterile laboratory.
Day 0: Fertilization
Within hours of retrieval, the eggs are identified, cleaned, and prepared.
- Conventional IVF: Roughly 50,000 sperm are placed in a dish with the egg, and the strongest one penetrates naturally.
- ICSI (Intracytoplasmic Sperm Injection): For about 70% of cases (and nearly all male factor infertility cases), we use ICSI. An embryologist selects a single, perfect sperm and manually injects it into the egg.
Day 1: The Fertilization Check
The morning after retrieval, we check how many eggs were fertilized. Normal fertilization is seen as two “pronuclei” (one from the egg, one from the sperm). On average, expect about 70–80% of mature eggs to fertilize.
Day 3: The Cleavage Stage
The embryo should now have 6–8 cells. In the past, clinics transferred embryos on Day 3. Today, we prefer to wait until Day 5. Why? Many embryos that look healthy on Day 3 stop growing by Day 5 because of genetic errors. Waiting acts as a natural filter for quality.
Day 5-7: The Blastocyst
This is the goal. A blastocyst is an embryo that has divided into 100+ cells and separated into two distinct cell types:
- Inner Cell Mass (ICM): The cells that become the fetus.
- Trophectoderm: The cells that become the placenta.
Embryo Grading: You might hear your doctor say you have a “4AA” or “5BB” embryo.
- Number (1-6): The expansion of the embryo (6 is fully hatched).
- First Letter (A-C): Quality of the Inner Cell Mass (Baby).
- Second Letter (A-C): Quality of the Trophectoderm (Placenta).
- Note: An “A” grade is pretty, but “B” grade embryos make beautiful babies too.
Phase 5: Preimplantation Genetic Testing (PGT-A)
Optional but increasingly common.
If you choose PGT-A, the embryologist uses a laser to safely remove 5–7 cells from the trophectoderm (placenta part) of the blastocyst. The embryo is then flash-frozen (vitrified) while the cells are sent to a genetics lab.
- What it tells us: Is the embryo Euploid (46 chromosomes) or Aneuploid (abnormal count)?
- The Benefit: Transferring a euploid embryo increases implantation rates to over 60–70% and drastically lowers miscarriage rates, as chromosomal error is the #1 cause of early pregnancy loss.
For more on the history and ethics of this technology, see Wikipedia: Preimplantation genetic diagnosis.
Phase 6: The Embryo Transfer
If you did PGT-A or if your hormone levels were too high during retrieval (posing a risk of OHSS), you will do a Frozen Embryo Transfer (FET) about a month later.
Preparing the Uterus
You will take Estrogen (pills, patches, or shots) to thicken your uterine lining. Once the lining looks “trilaminar” (three-layered) and thick enough (usually >7mm), you start Progesterone. Progesterone transforms the lining, making it “receptive” or sticky for the embryo.
The Procedure
This is the easiest part of the entire journey.
- No Anesthesia: You are awake.
- Full Bladder: You need a moderately full bladder, which helps push the uterus into a better position for ultrasound viewing.
- The Transfer: The embryologist thaws the embryo. Dr. Abdallah loads it into a soft, flexible catheter. Using abdominal ultrasound to see, he guides the catheter through the cervix and places the microscopic embryo at the top of the uterine cavity.
- The “Glitter”: On the ultrasound screen, the air bubble holding the embryo flashes white. Patients often describe it as seeing a “spark” or “glitter” as their potential child enters the womb.
Phase 7: The Two-Week Wait
After transfer, you continue Progesterone support. Then, you wait.
- Day 9 or 10 post-transfer: We perform a blood test called a Beta HCG. This measures the pregnancy hormone.
- Why not a home test? Home urine tests can be misleading. A blood test gives us a quantitative number. We want to see not just a positive, but a number that doubles every 48 hours, indicating a viable, growing pregnancy.
Frequently Asked Questions About IVF Process
How many eggs do I need for a baby?
It depends on your age. This is often called the “IVF Funnel.”
- Under 35: You might need 8–10 eggs to get 1 normal blastocyst.
- Over 40: You might need 15–20 eggs to find 1 normal blastocyst, because egg quality declines with age (more chromosomal errors).
- Insight: It only takes one. We have had patients with only two eggs retrieved who ended up with a healthy baby.
Does IVF cause cancer?
Large-scale studies have shown no significant increase in breast or ovarian cancer risk from IVF medications. The hormones leave your system quickly. The primary long-term risk to watch is for the baby (slightly higher risks of low birth weight), but this is often due to the underlying infertility or age of the mother, not the IVF technology itself.
What are the side effects?
- During Stims: Bloating, mood swings, breast tenderness, headaches.
- After Retrieval: Constipation (from anesthesia/pain meds) and spotting.
- OHSS (Ovarian Hyperstimulation Syndrome): In rare cases (<1%), ovaries swell with fluid. Symptoms include rapid weight gain (3lbs+ in a day), severe abdominal pain, and nausea. Call your clinic immediately if this happens. We use “Lupron triggers” now to virtually eliminate this risk.
Can I choose the gender?
Yes. If you undergo PGT-A testing, the genetic report will verify the sex chromosomes (XX for female, XY for male). You can choose which healthy embryo to transfer first. This is known as “Family Balancing.”
Why IVF Remains a Path Toward Possibility
IVF remains a source of hope because it creates options when biology becomes uncertain. For many individuals and couples, it offers a medically guided route to parenthood that may not be achievable through natural conception. The science behind IVF is advanced, but the meaning of the process is personal.
Every injection, every ultrasound, and every lab step exists for one purpose: to give you the strongest possible chance of a healthy pregnancy. Success is never guaranteed, yet IVF opens doors for patients facing diminished ovarian reserve, blocked fallopian tubes, male-factor infertility, or unexplained challenges.
At American Reproductive Centers, we focus on delivering reliable, high-quality IVF treatments. Our team provides clear explanations, consistent communication, and thorough guidance at every stage of treatment. Patients can expect accurate information, careful monitoring, and a professional approach designed to improve outcomes and reduce stress throughout the IVF process.
About the Author
Dr. Maher Abdallah, MD, FACOG, FACS
Medical Director, American Reproductive Centers
Dr. Abdallah is a double board-certified specialist in Reproductive Endocrinology/Infertility and Obstetrics/Gynecology. A widely respected figure in the field, he has been featured on NBC News and recognized as a Teaching Fellow of the Year at the University of Louisville. With over two decades of experience, Dr. Abdallah specializes in helping patients with diminished ovarian reserve, recurrent pregnancy loss, and previous IVF failures.
