IVF Medications Guide — Injections, Dosing & Side Effects

One of the most daunting aspects of IVF for most patients is the medications. Before your first injection, you may be looking at a refrigerator stocked with multiple pens, vials, and syringes, and a protocol calendar that specifies exact times for each drug. Understanding what each medication does — and why it's used — takes away much of the anxiety.

This guide covers every major category of IVF medication, drawing on ASRM clinical practice guidelines and FDA prescribing information. You'll learn what each drug does, what doses are typical, what side effects to expect, and how much each costs.

Why IVF Requires So Many Medications

In a natural menstrual cycle, your pituitary gland releases a small pulse of FSH (follicle-stimulating hormone) that nudges a single dominant follicle to grow and release one egg. IVF requires multiple eggs to maximize the chances of obtaining several healthy embryos.

To achieve this, the IVF protocol must:

1. Stimulate the ovaries to grow multiple follicles simultaneously (gonadotropins)
2. Prevent premature ovulation before retrieval (GnRH agonists or antagonists)
3. Trigger final egg maturation at precisely the right time (trigger shot)
4. Support the uterine lining after retrieval and through early pregnancy (progesterone, estrogen)

Each medication category addresses one of these four goals.

Category 1: Gonadotropins (Stimulation Medications)

Gonadotropins are the core of IVF stimulation. They are injectable hormones — FSH, LH, or a combination — that directly stimulate the ovarian follicles to grow.

FSH-only Gonadotropins

Follitropin alfa (Gonal-F): A recombinant FSH product administered by subcutaneous injection. Available as a pre-filled pen or multi-dose vials. One of the most widely used gonadotropins worldwide.

Follitropin beta (Follistim AQ): Another recombinant FSH product, functionally equivalent to Gonal-F. Available in a cartridge pen system.

Follitropin alfa biosimilar (Omnitrope): A biosimilar to Gonal-F approved by the FDA. Clinically equivalent but substantially less expensive — often 30–50% cheaper than branded gonadotropins.

FSH + LH Combination Gonadotropins

Menotropins (Menopur): Contains both FSH and LH activity (derived from the urine of postmenopausal women). The LH component may benefit patients with low AMH or older patients who need LH to support follicle development. Must be reconstituted from powder before injection.

Lutropin alfa (Luveris): Recombinant LH, sometimes added to a primarily FSH protocol for patients with very low LH or poor responders.

Typical Dosing

Starting doses vary considerably based on ovarian reserve:

Doses are adjusted up or down based on follicle growth observed at monitoring ultrasounds. Stimulation typically continues for 8–14 days.

Gonadotropin Side Effects

• Bloating and abdominal distension: Nearly universal as follicles enlarge the ovaries
• Mood changes: Fluctuating estrogen levels can cause irritability, tearfulness, or anxiety
• Injection site reactions: Redness, bruising, and mild stinging are common and resolve quickly
• Breast tenderness
• Fatigue
• Ovarian hyperstimulation syndrome (OHSS): The most serious risk — see below

Category 2: GnRH Agonists and Antagonists (Ovulation Suppression)

Without suppression, the LH surge that triggers ovulation would occur naturally during stimulation, releasing follicles before your physician can retrieve them. GnRH agonists and antagonists both prevent this — through opposite mechanisms.

GnRH Antagonists (Ganirelix, Cetrotide)

Mechanism: GnRH antagonists immediately block GnRH receptors in the pituitary, rapidly suppressing LH. They take effect within hours of the first dose.

When used: Added to the stimulation protocol around day 5–6 of injections, once lead follicles reach approximately 12–14mm. Continued through trigger day.

Administration: Single subcutaneous injection once daily (Ganirelix 0.25 mg or Cetrotide 0.25 mg).

Why antagonist protocols are now preferred: They require fewer days of suppression medication, involve no "flare" effect, and are easier to coordinate. The antagonist protocol is the standard of care at most U.S. clinics today.

Side effects: Injection site reactions; minimal systemic effects.

GnRH Agonists (Leuprolide / Lupron)

Mechanism: Paradoxically, GnRH agonists initially cause a surge of LH and FSH ("flare"), then — with continued use — cause downregulation and suppression of pituitary function. This suppression effect is what's used in long protocols.

Long Lupron protocol: Leuprolide is started in the luteal phase of the cycle before stimulation. After 10–14 days, suppression is confirmed by ultrasound and estradiol blood level, then gonadotropin stimulation begins. Leuprolide continues at a reduced dose through trigger day.

Micro-flare (flare) protocol: For poor responders, Lupron is started at the beginning of the stimulation cycle in low dose to exploit the initial FSH flare effect before suppression occurs.

Side effects of GnRH agonists: Menopausal-like symptoms during the suppression phase — hot flashes, insomnia, headaches, vaginal dryness, mood changes. These resolve after the medication is discontinued.

Category 3: The Trigger Shot

When your follicles are mature (lead follicles ≥18mm), the trigger shot is given to complete egg maturation and synchronize the eggs for retrieval.

hCG Trigger (Ovidrel, Pregnyl, Novarel)

Mechanism: Recombinant or urinary hCG mimics the LH surge that normally triggers ovulation. The egg retrieval is scheduled exactly 35–36 hours after the trigger.

Ovidrel: 250 mcg recombinant hCG. Subcutaneous injection. Convenient pre-filled syringe.

Pregnyl / Novarel: Urinary hCG (5,000–10,000 IU). Must be reconstituted from powder. Less expensive than Ovidrel.

Who should NOT use hCG trigger alone: Patients with many large follicles (15+) are at high risk for severe OHSS when given hCG, because hCG has a long half-life (5–7 days) and continues stimulating the ovaries after retrieval.

GnRH Agonist Trigger (Lupron Trigger)

Mechanism: A single dose of leuprolide causes the pituitary to release its own stored LH and FSH (the natural LH surge). Because it's cleared quickly, it does not cause prolonged ovarian stimulation.

Advantage: Dramatically reduces OHSS risk. Preferred for high responders and patients at OHSS risk.

Limitation: Not compatible with the long Lupron protocol (the pituitary is already suppressed). Must be used in an antagonist protocol. Requires more intensive progesterone supplementation after retrieval, as the corpus luteum function is reduced.

Dual trigger: Some physicians use both a low-dose hCG and leuprolide simultaneously to improve oocyte maturity rates while reducing OHSS risk compared to hCG alone.

Exploring Options Before IVF?

Before navigating the complexity of IVF medications and injections, many individuals and couples explore whether at-home insemination might be an appropriate first step for their situation.

MakeAMom makes reusable at-home insemination kits designed for a range of situations: the CryoBaby for frozen or low-volume sperm, the Impregnator for low-motility sperm, and the BabyMaker for those with vaginal sensitivities. Kits cost a fraction of clinical treatment and ship discreetly.

Explore home insemination kits at MakeAMom →

Category 4: Progesterone Support

After egg retrieval, the corpus luteum — the structure left behind after follicle rupture — produces progesterone to support the uterine lining. In IVF cycles, this function is often impaired because multiple follicles are aspirated during retrieval, and additional progesterone supplementation is required.

Intramuscular Progesterone in Oil (PIO)

Description: Progesterone dissolved in oil (sesame, peanut, or ethyl oleate oil) is injected intramuscularly, typically into the upper outer quadrant of the buttock.

Administration: Daily injection, beginning the evening of or the day after egg retrieval. Typically continues for 8–10 weeks after a positive pregnancy test.

Advantages: Achieves very high and consistent serum progesterone levels. Well-studied efficacy.

Disadvantages: Painful. Injection site lumps and skin reactions are common. Requires assistance to reach the injection site, or an awkward self-injection technique.

Managing PIO discomfort: Warming the oil before injection (hold the syringe in your hand or use a heating pad for 5 minutes), using a slow, steady injection technique, and applying heat and gentle massage to the site afterward significantly reduce discomfort.

Vaginal Progesterone

Endometrin (progesterone vaginal insert): 100 mg tablets inserted vaginally 2–3 times daily. Convenient; avoids intramuscular injections. Local uterine effect is strong.

Crinone 8% (progesterone vaginal gel): Applied once or twice daily with an applicator. Somewhat "clumpy" residue is a common complaint but is not harmful.

Prometrium (oral micronized progesterone used vaginally): Some physicians prescribe standard oral capsules for vaginal use, which is off-label but effective.

Comparison — IM vs vaginal:

Many clinics now use vaginal progesterone as first-line, reserving IM progesterone for patients with elevated progesterone requirements or history of implantation failure.

Category 5: Estrogen Supplementation

In frozen embryo transfer (FET) cycles using a medicated protocol, the uterine lining must be prepared with exogenous estrogen before progesterone is added.

Estradiol valerate (Delestrogen): Intramuscular injection every 2–3 days. Achieves high, stable estradiol levels.

Estradiol patches (Vivelle-Dot, Climara): Transdermal patches changed every 2–3 days. Convenient; avoids injections.

Estradiol tablets (Estrace) orally or vaginally: Oral route is most convenient but has higher variability in absorption. Vaginal administration improves local uterine effect.

Estrogen is typically started on cycle day 2–3 and continued for 10–14 days before progesterone is added, allowing the lining to thicken to at least 7–8mm.

Medication Cost Table — 2025

Costs vary significantly depending on your protocol, response, pharmacy, and whether you use branded or generic/biosimilar products. Ask your clinic's pharmacy team about manufacturer coupons and patient assistance programs.

Injection Technique — Key Tips

Many patients have never self-injected before. Proper technique makes the process much more manageable:

Subcutaneous injections:

• Rotate injection sites within the lower abdomen (avoiding a 2-inch radius around the navel)
• Pinch a fold of skin between your fingers
• Insert needle at a 45–90° angle
• Inject slowly and steadily
• Remove needle, release skin fold, apply gentle pressure (do not rub)
• Ice the site beforehand if you're sensitive to needles

Reconstituting powder medications (Menopur, Pregnyl):

• Use the provided diluent syringe to mix the powder; swirl gently, do not shake
• Multiple vials can often be mixed into a single syringe (confirm with your clinic)
• Reconstituted medication must be used immediately or refrigerated per instructions

Keeping organized:

• Use a printed protocol calendar; check off each medication as you take it
• Keep refrigerated medications in a clearly labeled area
• Set phone alarms for injection times — consistency matters, especially for the trigger shot

Managing OHSS Risk

Ovarian hyperstimulation syndrome (OHSS) occurs when the ovaries overrespond to stimulation. Mild OHSS (bloating, mild pain) is common and resolves on its own. Severe OHSS involves ascites (fluid in the abdomen), hemoconcentration, and rarely, thrombosis — it is a medical emergency.

Risk factors: Young age, low body weight, high AFC, PCOS, previous OHSS, high estradiol levels during stimulation.

Prevention strategies:

• Antagonist protocol (allows Lupron trigger instead of hCG)
• "Coasting" — temporarily stopping gonadotropins when estradiol rises rapidly
• Lupron or dual trigger instead of hCG trigger
• Freeze-all strategy — freeze all embryos and delay transfer to a subsequent cycle, eliminating the pregnancy hCG that worsens OHSS

For patients with PCOS or a history of OHSS, discuss these strategies with your physician before starting stimulation. Our PCOS and IVF guide covers OHSS in more detail for that population.

Questions to Ask Your Clinic About Medications

Before starting your cycle, confirm the following with your care team:

• Which pharmacy should I use? Do you have preferred specialty pharmacies?
• Is there a patient assistance or medication coupon program I qualify for?
• What is the exact time my trigger shot must be given?
• What should I do if I miss a dose?
• What OHSS symptoms should prompt me to call the clinic?
• Will I need IM progesterone or is vaginal progesterone an option?

Frequently Asked Questions

Q: What is the difference between the antagonist and long Lupron protocols? A: The antagonist protocol (the current standard) starts gonadotropin injections on day 2–3 of the cycle, then adds a GnRH antagonist (Ganirelix or Cetrotide) around day 5–6 to prevent premature ovulation. The long Lupron protocol begins Lupron in the prior cycle to suppress the pituitary before stimulation starts, allowing fuller physician control. Antagonist protocols are preferred today because they require fewer suppression days and allow a Lupron trigger to reduce OHSS risk.

Q: Why is the trigger shot timing so critical? A: The trigger shot — hCG or a Lupron trigger — initiates the final maturation of eggs and synchronizes them for retrieval. Egg retrieval is scheduled exactly 35–36 hours after the trigger, just before natural ovulation would occur. If the trigger is given too early or too late, eggs may not be mature or may ovulate before retrieval. Your clinic will specify an exact time (often 10 PM or midnight) — set a phone alarm.

Q: What is the difference between hCG and Lupron triggers? A: An hCG trigger (Ovidrel, Pregnyl) mimics the LH surge and is the most common choice. A Lupron (GnRH agonist) trigger causes the pituitary to release its own natural LH surge, which clears more quickly than hCG — dramatically reducing OHSS risk. Lupron triggers are preferred for high responders and PCOS patients but cannot be used in long Lupron protocols (since the pituitary is already suppressed) and require more intensive progesterone support after retrieval.

Q: Is vaginal progesterone as effective as intramuscular injections? A: Multiple randomized controlled trials have found equivalent live birth rates between vaginal and intramuscular progesterone routes in most patient populations. Vaginal progesterone (Endometrin, Crinone) achieves strong local uterine concentrations even when serum levels appear lower, due to a direct uterine absorption effect. Many clinics now use vaginal progesterone as first-line, reserving IM injections for patients with elevated requirements or prior implantation failure.

Q: How can I reduce the cost of IVF medications? A: Key strategies include asking about biosimilar gonadotropins (Omnitrope is 30–50% cheaper than branded Gonal-F or Follistim with equivalent efficacy), checking manufacturer patient assistance programs, using specialty pharmacy discount programs, and confirming whether your employer's fertility benefits cover medications. Total medication costs vary from $3,000–$7,000 depending on protocol and individual response.

Key Takeaways

• Gonadotropins drive follicle growth; GnRH antagonists or agonists prevent premature ovulation
• The trigger shot — hCG or Lupron — is time-critical and must be given within a specific window
• Progesterone support is required after every IVF transfer and typically continues for 8–10 weeks post-transfer if pregnancy occurs
• Medication costs of $3,000–$7,000 are the largest variable in total IVF pricing
• Biosimilar gonadotropins can significantly reduce medication costs with equivalent efficacy

This article is for informational purposes only and does not substitute for individualized medical advice from your reproductive endocrinologist. Dosing information is general; your protocol will be customized to your specific clinical situation.