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Ovarian sensitivity index (OSI) calculator

How well did I respond to the medicine?

Q: Why not just count the eggs?

Because ten eggs on 1,500 IU and ten on 4,500 IU are very different cycles. OSI captures the cost of the response, which is what informs the next protocol.

Q: Does high sensitivity mean risk?

It can. A high OSI sometimes prompts a lower starting dose next cycle specifically to reduce the chance of ovarian hyperstimulation.

Q: Does a low OSI mean the dose was wrong?

Not necessarily — it may mean your ovaries are less sensitive, which is information rather than error. What it does prompt is a conversation about whether a higher dose would help or simply cost more without changing the yield.

Eggs retrieved relative to the total gonadotropin dose used. Separates a good response from an expensive one.

Eggs retrieved

Total collected

Total gonadotropin dose

Sum across the cycle

These are example numbers. Replace them with yours, then press Calculate.

Example answer

4.89per 1000 IU

1.7–5

Within the range most cycles fall into.

This is a guide, not a diagnosis. Share the result with your doctor.

Your result on the scale

The ranges this calculator uses. Yours is highlighted.

Your numbers

Everything worked out from what you entered.

Eggs retrieved: 11
Total dose: 2250 IU
Eggs per 1000 IU: 4.89

What each result means

Your result is highlighted. Your own clinic's advice always comes first.

Your result<1.7

Low sensitivity — a high dose produced relatively few eggs. Commonly used as a marker of poor response independent of the number retrieved.

Your result1.7–5

Within the range most cycles fall into.

Your result5+

High sensitivity. A modest dose produced a good yield, which sometimes prompts a lower starting dose next time to reduce OHSS risk.

Where this fits in your journey

The usual order, from trying to conceive to pregnancy. Not everyone needs every stage. This calculator belongs to stage 4.

Stage 4 · you are here

During an IVF cycle

Make sense of the numbers your clinic gives you.

Medicines
→
Egg collection
→
Your embryos

This calculator: How well did I respond to the medicine?

Calculators for what comes next

How this is worked out

Exact calculationArithmetic on the numbers you enter. If your inputs are right, this figure is right.

The ovarian sensitivity index is oocytes retrieved per 1000 IU of gonadotropin, separating a good response from an expensive one. Below about 1.7 indicates low sensitivity regardless of how many eggs were collected.

About this calculator

?What it tells you

Eggs compared with the total dose used. Eggs retrieved relative to the total gonadotropin dose used. Separates a good response from an expensive one.

✓When to use it

When comparing two cycles on different doses

iWhat you need

Eggs retrieved
Total gonadotropin dose (IU)

!What it cannot tell you

OSI informs protocol planning and is interpreted by a clinician alongside your monitoring data.

Common questions

Why not just count the eggs?

Because ten eggs on 1,500 IU and ten on 4,500 IU are very different cycles. OSI captures the cost of the response, which is what informs the next protocol.

Does high sensitivity mean risk?

It can. A high OSI sometimes prompts a lower starting dose next cycle specifically to reduce the chance of ovarian hyperstimulation.

Does a low OSI mean the dose was wrong?

Not necessarily — it may mean your ovaries are less sensitive, which is information rather than error. What it does prompt is a conversation about whether a higher dose would help or simply cost more without changing the yield.

Sources

OSI is calculated as oocytes retrieved divided by total FSH dose, multiplied by 1000. Cut-offs vary between publications.

In an emergency

If you have any of the warning signs listed here, don't wait for a test result or a calculator. Get help now.

112All emergencies, anywhere in India 108Ambulance

Also call your IVF clinic. Most clinics give an emergency number on your treatment or discharge sheet. Save it in your phone now, before you need it.