turtle - Is it Sharm-el-Sheikh you are going to? We've just booked to go there when I think I'm 28 weeks (Boxing Day to New Year's Day)instead of a two week tour round Mexico which we had planned ages ago but now think will be way too much for me. I've been to Sharm before at the same time of year and really like it and think it will be fine when I'm heavily pregnant - would definitely recommend it. it's a great place to relax and get some sunshine in the winter.
If it isn't Sharm then sorry cos the rest of this isn't that helpful as it's too specific, but if it is then here's the lowdown:
There is a modern international hospital there with English speaking doctors, even if they are probably more used to diving accidents than pregnant women... The hotels are generally of a very good quality (we're treating ourselves to a swish resort too), there are loads of nice restaurants with lots of choice of food (including a great Chinese) and it's very cosmopolitan (loads of Brits, Italians, Scandinavians and Russians!). Although you can't dive while pregnant (I'm very sad about this!), the snorkelling from the beach is amazing and you can do snorkelling boat trips as well. The temperature in winter is lovely - high 20s maybe low 30s so not too hot, but nice temperature water for swimming. There are also day trips to various bits of the Sinai desert and lots of activities although quad bike racing and camel riding may not appeal
I'm planning to take lots of books, relax on loungers, swim and snorkel, enjoy some sunshine and get to bed early every night!
Basically, although it is Egypt you should think of it as more like a European resort really so if you'd be happy in say the Canaries at 30 weeks then you would be fine there. Last time we did a day trip to Dahab which has loads of cool restaurants and is a bit funkier/low key (Sharm is more polished/glitzy and apparently has some casinos now as well) as well so would consider staying there. Not sure about other Red Sea resorts though.
I would say on the health front that there is no need to worry - bottled water freely available, and we didn't suffer any problems with the food. On flights, check carefully what coverage your travel insurance gives you as some may only cover you to 28 weeks and some may only cover you to a certain number of weeks even if you gave birth early (so e.g. if you were covered until 32 weeks but had baby and had to stay abroad after 32 weeks then you might not be covered for expenses after that date). It's about a 5 hour flight so not brilliant but not as bad as New York etc. You'll just have to walk along the aisle loads annoying the air hostesses and showing off some sexy support socks...
Hope that helps.