The 90 vs 120-day trap: why women look like “worse” repeat donors on paper

Here is a small detail that quietly shapes how we judge women donors.

Under India's national blood donor selection guidelines, the minimum gap before you can give whole blood again is 90 days for men and 120 days for women. Women have to wait longer between donations. That's the rule, and it exists for good reason.

How many days gap is needed between blood donations?

For whole blood: at least 90 days for men and at least 120 days for women, counted from your last donation. Platelet and plasma donations follow different rules, and the blood bank checks your eligibility again before every donation. If you are unsure, ask the blood bank or check the NBTC guidelines.

How a simple report makes women look worse

Picture a donor club in Behala or a blood bank in north Kolkata trying to see how many donors “came back.” A common, simple way to count is to use one window for everyone: did this person donate again within 6 months?

Look at what happens:

• A man becomes eligible again on day 90. Inside a 6-month window he has roughly 90 days to come back and be counted.
• A woman only becomes eligible again after 120 days. Inside the same window she has only about 60 days. If life gets busy for a couple of months, she drops out of the count, even though she was only eligible for part of that time. Use a tighter window, like 4 months, and she gets almost no chance at all.

So the report says women are poor repeat donors. In reality, many of them were just following the rules and waiting their turn.

This is a measurement trap. The data isn't lying on purpose. It is just asking the wrong question. And wrong numbers lead to wrong decisions: fewer camps aimed at women, less follow-up, and the old “women aren't committed” story getting repeated.

What to do instead

• Measure return based on each donor's own eligible date. For women, start counting from day 120.
• Compare “returned after becoming eligible” rather than “returned within X days.”
• Send reminders when a donor actually becomes eligible again, not before.

Our donor retention research with FBDOI and the West Bengal Voluntary Blood Donors' Forum keeps pointing back to this: women don't lack motivation. Some of the gap is in how we count.

If you're a donor

You don't need to track any of this yourself. Register as a donor on Haemologix: we keep your last donation date and only alert you for emergency requests once your gap is over. For the basics of who can donate, see our blood donation guide.