Thanks for the advice chefswife. I don't actually drink that much decaff, but do like a cup in the morning.
Rules of how much caffeine there is in decaff vary from the UK to the USA. We are covered by European Community (EC) guidelines which are as follows:
DECAFFEINATED COFFEE
Whatever method of decaffeination is used, the decaffeinated green coffee must contain less than 0.1 % caffeine (dry weight basis) to comply with EC regulations. This corresponds to about 3mg caffeine in a cup of decaffeinated coffee.
The info I found from the FDA was:
COFFEE (5 oz cup) CAFFEINE CONTENT (mg)
Drip method 110-150
Percolated 64-124
Instant 40-108
Decaffeinated 2-5
Instant Decaffeinated 2
Both countries agree that 5-10 cups of instant decaff, depending on their size, equal 1-2 cups caffeinated.
There are of course other considerations such as the method of caffeine extraction - water method being preferable.
Interestingly, I also noticed that most places seem to agree that green tea contains 30-60mg caffeine, the higher level being attributed to tea bags rather than loose tea. Caffeine intake from green tea can be reduced by only drinking the second infusion and drinking it whilst hot to reduce the breakdown and therefore release of caffeine into the water.
I have tried green tea in the past as DH loves it and I'm aware of the many health benefits, but I've never liked tea and just couldn't get on with the taste.
I don't drink soft drinks, just water and I won't be touching chocolate during this pregnancy either, so I think my caffeine levels should be ok.
It's a minefield isn't it, remembering all the things you can and can't eat and drink. The advice has changed for each of my pregnancies - I can hardly keep up!