Estimate when fertility returns after Depo using your last injection date, total injections, and whether a period has returned. Get median and 25th to 75th percentile months to ovulation, probability by month, first period timing, earliest reliable test day, and a care flag if no period by the threshold.
How this calculator works
- Inputs: date of last Depo injection, total injections, period returned since the last shot (Y/N), optional age and BMI band.
- Outputs: estimated months to ovulation (median and 25th–75th percentile), probability ovulation has returned by month X, expected timing of the first period, earliest reliable pregnancy test timing, and a care-flag if no period by the tool’s threshold.
Methodology & limits
The model starts from typical return-to-ovulation patterns after Depo and adjusts by reported injections and whether a period has returned. Age and BMI bands provide context. “Probability by month” is the chance that ovulation has happened by each month since the last shot. The first-period estimate follows the ovulation estimate with a typical luteal interval. The care-flag triggers at a set threshold within the tool.
This estimate cannot diagnose conditions or predict individual results. For personalised guidance or prolonged amenorrhoea, speak with a clinician.
Frequently asked questions
Can I ovulate before my first period?
Yes. Ovulation can return before the first period. The tool estimates when this is likely and suggests when to test.
Do more injections delay return to fertility?
Longer use can extend the time to ovulation for some people. The model uses your total injection count in its estimate.
Why do you ask if a period has returned?
A recent period is a signal that ovulation has likely resumed. It narrows the estimate for the next ovulation window.
Do age and BMI affect the result?
They are used as context in the model. Age often has a larger effect on overall chances once ovulation returns.
When should I seek care?
The tool shows a care-flag if no period by its threshold. This is educational only. If you are concerned, see a clinician.