A useful answer might be a comprehensive lists of cheeses which are ok, and of those which are not (are any of them ok in smaller quantities?)
Alternatively is there a sure way of telling if a cheese will be acceptable when you're pregnant once it has turned up at the dinner table?
The usual rule is that pasteurised, hard cheeses (such as Cheddar, Red Leicester etc) are safe, but you should avoid soft cheeses (such as Brie) and avoid all unpasteurised cheeses.
Pasteurisation kills off pretty much everything in a milk product, but soft cheeses can become a breeding ground for bacteria and dangerous moulds very rapidly, whereas hard cheeses are safe for a much longer time.
A comprehensive list isn't really possible, as there are dairies offering unpasteurised versions of many cheeses, but stick to hard cheeses only and even then avoid ones with any mould, even if they are supposed to be a mouldy cheese.
As was mentioned, the problem with cheese is the potential for Listeria. The risk is primarily for cheeses made from unpasteurized milk. Soft cheeses are the ones to double check, as the aging process used in hard cheeses, even those made with unpasteurized milk, makes the cheese inhospitable to Listeria cultures:
Hard cheeses have longer ripening periods, reduced moisture content and lower pH and are unlikely to support the survival and proliferation of Listeria and are therefore generally safe to consume by at risk groups
Depending upon your local food safety regulations, soft cheeses made with unpasteurized milk may be altogether rare, or obtainable only from specialty shops. Always check the label on any soft cheeses you may intend to consume while pregnant.
Another class of cheeses to avoid are "mold-ripened" (same source as above):
These cheeses are divided into two categories: white mould cheeses, which are surface ripened (i.e. Brie and Camembert ) and blue mould or blue veined cheeses, with mould throughout the cheese (i.e. blue, Gorgonzola, Stilton ).
The relatively high moisture content of the surface ripened cheeses, along with a nearly neutral pH in fully ripened cheese, allows rapid growth of Listeria bacteria. Mould ripened cheeses are also highly susceptible to surface contamination during ripening. These types of cheese should be avoided by at risk groups.
Finally, "whey cheeses" (typically Ricotta) have a high moisture content and growth of Listeria may occur if there is post-processing contamination.
In addition to these cheeses, we were also warned not to eat any cheeses that were sliced at a deli. The slicers at delis are often only washed once a day (if it is a reputable deli), and room-temperature cheese residue builds up on the slicer throughout the day. In some cases, the slicer may also be used to cut meats in addition to cheeses, increasing the risk of cross-contamination (sliced deli meats were another thing we were warned against).
Although cheese is very healthy and also good during pregnancy, some types might contain Listeria, which can cause serious problems.
Wikipedia quotes the "Center for Science in the Public Interest" with the following cheeses to avoid: "particularly soft-ripened cheeses like feta, Brie, Camembert, blue-veined, or Mexican-style queso blanco".
As a rule, pregnant women should avoid any unpasteurized cheeses. In Europe, the typical ones are french soft cheeses (Camembert, Brie, Roquefort; although there are pasteurized variants, too), very hard cheeses (Parmesan, Gruyére), other specialties (like Harzer). As a rule: the more "special" or "regional" a cheese, the higher the risk. Also, no matter whether a cheese is made from raw or pasteurized milk, pregnant women should avoid the crust, as it is more likely to harbour listeria or other bacteria than the inside.
Note: pregnant women should also avoid raw meat because it could cause Toxoplasmosis.
Anything that is not pasteurized. But if you look up the statistics on Listeria you have a 0.1% chance of these becoming a problem. If you listen to everyone out there of what you shouldn't eat they you well end up not being able to eat anything at all. Also location plays a part in this, in Australia all dairy products have to be pasteurized before being sold, I'm not sure of the law in other countries.
Really you can eat most things when your pregnant, just follow the same rules you would for any normal health eating.
In the UK, the NHS advice is to avoid:
Cheeses that are fine to eat:
