PMS vs PMDD: how to tell the difference, and why it matters at work.

Most people who menstruate get some premenstrual symptoms. PMDD, premenstrual dysphoric disorder, is much less common: it affects a small share of people, roughly 3 to 8 percent. It is not just "bad PMS" that you should push through. It is a condition with its own name, a doctor who can confirm it, and treatments that work for a lot of people.

The short version

• How common: PMS is very common. PMDD is rare by comparison.
• How strong: PMS is usually mild to moderate. PMDD is severe enough to be disabling for some days.
• What leads: PMS is often physical as much as emotional (bloating, cramps, tiredness, a shorter fuse). PMDD always includes mood: deep sadness, anxiety, irritability or anger that feels out of proportion, or losing interest in things you care about.
• Daily life: with PMS you usually keep functioning. With PMDD, work, relationships and sleep often take a real hit.
• Cause: PMDD is thought to be a strong sensitivity to normal hormone changes, not abnormal hormone levels. That is why a blood test cannot show it.

What they share: the timing

Both tend to start in the week or two before a period and ease within a few days of it starting. Then comes a stretch where you feel like yourself again. That on-off pattern is the signature of both. If you feel low all month and a bit worse before your period, something else may be going on, and that is worth raising with a doctor too.

The question that tells them apart

Ask yourself one question on hard days: what did this cost me today? With PMS, the answer is often "a slower afternoon" or "I was snappy in standup." With PMDD, it is more like "I could not get through the review," "I cried in the bathroom between calls," or "I said something to my team I would never normally say." Severity and impact are what separate the two, not the list of symptoms.

How to find out which one you have

There is no lab test for PMDD. A doctor works it out from your history and from a record of your symptoms, and checks for other causes such as thyroid problems. PMDD usually means five or more symptoms in the days before your period, with at least one of them about mood. So the most useful thing you can do is keep that record.

• Check in once a day for at least two cycles, on good days too.
• Rate mood, energy, sleep and focus, and note any body symptoms.
• Add one line about impact: did it get in the way of work, friends or home today?
• Mark the first day of each period, then line the days up against it.

If your hard days cluster before your period and clear after it, cycle after cycle, you have a pattern. If the impact line keeps saying yes, bring it to a doctor. Notes beat memory, which tends to blur a hard week into a hard month.

What each one means for your work week

With PMS, a bit of planning goes a long way. Do the prep for big meetings a few days earlier, leave fifteen minutes between calls, and keep the evening before a big day light so you sleep well.

With PMDD, plan the same way, but put even less in your hardest days and decide on a good day what you will do on a bad one: a line to buy time in a tense meeting, a rule to send hard emails tomorrow morning, a short walk outside. Planning helps you cope. It does not treat PMDD, so get support from a doctor alongside it.

How Maeve does it

Maeve asks one short check-in a day and learns your own pattern. It puts your likely hard days next to the meetings you already have, two weeks ahead, and gives you two suggestions a day, one for work and one for life. It never edits, moves or deletes a meeting, and it does not use AI. After two or three cycles, Pattern can build a doctor report comparing the days before your period with the days after it. Your data is end-to-end encrypted, so Maeve cannot read it.

Maeve is not a medical device and does not diagnose or treat any condition. If your symptoms worry you, talk to a doctor. If your mood gets very low, or you have thoughts of hurting yourself, please talk to a doctor or someone you trust now, not after the next cycle. In the US you can also call or text 988.