Education Hub
IVF & Treatments 9 min read

IVF Medications Explained: Every Injection and What It Does

What every IVF medication does: FSH, GnRH antagonist, trigger shot, progesterone — brand names, doses, side effects, and self-injection tips. ESHRE 2023.

FertilityConnect Medical Team Reviewed 9 May 2026Share
ℹ️This article is reviewed against ASRM, ESHRE, and ACOG clinical guidelines and updated regularly. It is for educational purposes only and does not replace a consultation with a qualified fertility specialist.

IVF Medications: Every Injection and What It Does

Most patients find the medication aspect of IVF the most intimidating — a collection of unfamiliar drugs with complex names, administered by self-injection. This guide demystifies every medication used in a standard IVF cycle.

Phase 1: Ovarian Stimulation (Days 2–12)

FSH Injections — Gonadotropins What they are: Synthetic copies of the body's naturally occurring FSH (follicle-stimulating hormone). Used to stimulate multiple follicles to grow simultaneously — the foundation of IVF.

Common brands in India:

BrandGeneric NameType
Gonal-FFollitropin alfaRecombinant FSH
MenopurHuman menopausal gonadotropinFSH + LH blend
FostimonUrofollitropinUrinary FSH
PuregonFollitropin betaRecombinant FSH
BravelleUrofollitropinUrinary FSH

Dose: Individualised based on AMH and AFC. Typical range: 150–300 IU daily. Women with low AMH may need 300–450 IU. Women with high AMH (PCOS) start lower, typically 100–150 IU.

How administered: Subcutaneous (under the skin) injection into the abdomen or thigh. Pre-filled pens (Gonal-F, Puregon) are the easiest. Standard syringes with powder-and-diluent vials (Menopur, Fostimon) require mixing.

Side effects: Injection site bruising; mild bloating; breast tenderness as estrogen rises; occasional mild headache. More significant bloating and discomfort as follicles enlarge toward trigger day.

LH Activity (Luteinising Hormone) Some protocols add a small LH component to support follicle quality — particularly in women with low LH or older women. Achieved by using Menopur (FSH+LH blend) or adding Luveris (recombinant LH) to pure FSH.

Phase 2: Preventing Premature Ovulation (Days 5–12)

GnRH Antagonists What they do: Block the pituitary from releasing a premature LH surge — which would cause ovulation before the eggs are retrieved. Added after follicles reach ~14mm.

Common brands:

  • Cetrotide (cetrorelix) — powder + diluent; self-mixed
  • Orgalutran (ganirelix) — pre-filled syringe; easiest

How administered: Subcutaneous injection. Taken daily from approximately day 5–6 of stimulation until trigger day.

Side effects: Minimal. Mild injection site reactions. No hot flushes (unlike the older GnRH agonist "long protocol").

Why antagonist protocol replaced the "long protocol": Older IVF cycles used a GnRH agonist (Lupron/buserelin nasal spray or injection) starting 2–3 weeks before stimulation to "down-regulate" the pituitary. This worked but required a longer pre-treatment phase and caused menopausal-like symptoms (hot flushes, mood changes, headaches). The modern antagonist protocol (stimulate → add antagonist at day 5–6 → trigger) achieves the same result faster and with fewer side effects. GnRH agonist long protocol is still used in certain specific circumstances.

Phase 3: Trigger Injection (Day 10–12)

hCG Trigger (Ovitrelle, Pregnyl, Choragon) What it does: Mimics the natural LH surge to trigger final egg maturation. Retrieval is timed exactly 34–36 hours later.

How: Subcutaneous or intramuscular injection. Usually given at a precise time in the evening — often 10–11 PM for a morning retrieval.

Side effect warning: hCG trigger significantly increases OHSS risk in high-responder women (PCOS, AMH >3.5, >20 follicles). For this group, a GnRH agonist trigger is preferred.

GnRH Agonist Trigger (Lupron, Buserelin, Triptorelin) What it does: Triggers a brief natural LH surge from the pituitary — equally effective for egg maturation but with dramatically lower OHSS risk. Used in high-responder women; usually requires a freeze-all strategy (no fresh transfer), followed by FET in a subsequent cycle.

Phase 4: Luteal Support (Embryo Transfer Through Early Pregnancy)

Progesterone — The Most Important Post-Transfer Medication Progesterone is essential to maintain the uterine lining in its receptive state after embryo transfer. Without adequate progesterone, the lining sheds and pregnancy cannot continue.

Forms:

FormBrandNotes
Vaginal pessaryCyclogest, Crinone, EndogestMost common; twice or three times daily
Oral tabletsDuphaston, UtrogestanLess commonly used alone; sometimes combined
Vaginal gelCrinone 8%Once daily; some women prefer to pessaries
Intramuscular injectionProgesterone in oilHighest blood levels; used for certain protocols or pessary intolerance

Important: Do NOT stop progesterone without your doctor's advice, even if you feel fine or have symptoms. Sudden withdrawal causes the lining to shed and can end a pregnancy.

Estrogen (in FET cycles) For medicated frozen embryo transfers, oral estradiol (Progynova) or patches (Estradot) are taken for 12–14 days to grow the uterine lining before progesterone starts. The dose is typically 2mg three times daily, increasing to 4–6mg if the lining is slow to respond.

Additional Medications You May Be Prescribed

Aspirin (75mg): Low-dose aspirin is widely used to improve uterine blood flow. Started at the beginning of the stimulation cycle or FET preparation. Some evidence supports use; ASRM considers it acceptable despite limited RCT data.

Metformin (for PCOS patients): Insulin sensitiser that reduces OHSS risk and improves IVF outcomes in PCOS. Continued from before IVF through the first trimester if pregnancy occurs.

Prednisolone / Dexamethasone: Steroids used empirically by some clinics to reduce immune reaction to the embryo. Evidence is limited but they are commonly prescribed in recurrent implantation failure protocols.

Antibiotics (Doxycycline): Given around the time of egg retrieval to reduce infection risk. Also used pre-treatment for couples with elevated leukocytes in semen.

Self-Injecting: Practical Tips

  • Subcutaneous injections go into the fatty layer of the lower abdomen or outer thigh — rotate sites to minimise bruising
  • Take medications from the fridge 15 minutes before injecting — room temperature injection hurts less
  • Ice the site for 30 seconds before injecting if anxious about pain
  • Pre-filled pens (Gonal-F, Orgalutran) are the easiest — the click mechanism confirms dose delivery
  • Dispose of all sharps in a sharps container (available from any pharmacy)
  • If you miss a dose — contact your clinic. Do not double-dose without advice.

Reference: ASRM Practice Committee — Controlled Ovarian Stimulation, 2023. ESHRE Guideline — Ovarian Stimulation for IVF/ICSI, 2023.

IVF medications IVF injections FSH injections IVF GnRH antagonist IVF trigger shot progesterone IVF IVF drugs

Frequently Asked Questions

Are IVF injections painful?

Most patients describe IVF injections as mildly uncomfortable rather than painful — similar to a small pinch. Pre-filled pens (Gonal-F, Puregon, Orgalutran) are easiest to use and most comfortable. Letting the medication reach room temperature before injecting and rotating injection sites reduces discomfort. Most patients find the injections manageable within the first few days.

What is the trigger shot in IVF?

The trigger injection (typically Ovitrelle — recombinant hCG) is given when the lead follicles reach 17–20mm. It triggers the final maturation of the eggs, and retrieval is timed precisely 34–36 hours later. The trigger must be given at the exact prescribed time. For women at high risk of OHSS (PCOS, high AMH), a GnRH agonist trigger is used instead — it is equally effective but dramatically reduces OHSS risk.

How long do you take progesterone after IVF?

Progesterone support typically begins on the day of trigger injection (or day of transfer in a frozen cycle) and continues until at least 10–12 weeks of pregnancy if the transfer is successful. If the transfer fails, progesterone is stopped and a period follows within a week. Do not stop progesterone without your doctor's specific advice — sudden withdrawal can disrupt an early pregnancy.

Medical Disclaimer: This content is for educational purposes only. It is reviewed against ASRM, ESHRE, and ACOG clinical guidelines but does not constitute medical advice. Always consult a qualified reproductive endocrinologist for personalised guidance.