This may be a stupid question, but is it better to lug my products with me or are they available at reasonable prices in Paris or London?

They are indeed available at reasonable prices. I am sure you do not want to be caught unexpected with nothing, though. Also, shops or pharmacies etc may be closed on Sundays, so don't count on that. I remember once I was in Salzburg and some ditz came into a souvenir shop trying to get such products because she was actually traveling around without any, as if she didn't know this was going to happen sometime again to her around that time. It was Sunday, so most everything was closed, but the proprietor told her to go to the one pharamacie that was open that day. There is always one that is open on Sundays, for safety reasons.

Actually I never know if I'll need them - perimenopausal, don'tya know? That's why I was asking.

Too much information, Illegallady...

Just carry a few - if you need more you can easily get what you want at any pharmacy - as long as you're not picky about exact style/brand.

You can definately find feminine products in Paris or London, but 1) the US dollar exchange rate sucks, so you will most likely be paying more for them, 2) we all have our favorite brand...so I would suggest bringing your own....it is just more comforting and won't take up too much space.

Ditto, ilovetotravel29!

Eloise--it's not "too much information"; there have been far more explicit discussions of the topic here, and Illegallady has expained exactly why she has a question about this---during perimenopause, "Aunt Flo" can arive unexpectedly, and with a vengence. Obviously you are young and have not yet experienced this. Since when did "menopause" become a dirty word?

For illegallady, I suggest you take a few, and if it is necessary buy more there. I wouldn't worry about the cost; it can't be much higher, and there's no point in carrying around a bunch of stuff you may or may not need. And buying them in a foreign country can be an interesting cultural experience (boy, could I tell you stories about that!). But Europeans in general are a whole lot more open about this than people in the U.S. And you can find the same brands---or maybe something better.

And it always stops the luggage searchers in their tracks at the airport

I remember in France completely forgetting what the things are called.
I had to ask for "les choses donc les femmes ont besoin chaque mois".

In the UK, you'll find everything you need at Boots, a large drugstore chain with branches on every main street, many of which are open on Sundays (though perhaps with shorter opening hours).
There are some differences between products available in the UK and US, but there's plenty of choice and prices aren't exhorbitant (cheaper in the UK than in France, I reckon).

In Paris, head for Monoprix as it's easier to browse and find what you need than in small pharmacies, where you may have to ask at the counter.

Always carry at least a small back-up supply. Here in the US we are so used to being able to shop 24 hours a day for necessary items. The rest of the world isn't like this. I was desperate one evening, say 7 pm, in a medium sized French town. Looked and looked and couldn't find a thing. Finally was so relieved we ran across a small neighborhood grocery. $8 for 20 tampons. But, I would have paid anything.

LOVE Boots and Monoprix's--you can get anything there!

Some things I get that are OTC here require you to speak to a specialist there--including some womanly kinds of products. So if you think you might need anything, bring it!