We had another visit to the OB today, and Lisa had another ultrasound done. Baby A (the girl) weighed in at 4lb 7 oz (was 3 lb 10 oz on Dec 27) and Baby B (the boy) weighed in at 5 lb 6 oz (up from 4 lb 7 oz on Dec 27th). Everything is progressing very well. The heart rates are excellent, the fluid is perfect, and the blood flow to both is doing very well.
So we've just finished week 34, and the average birth for twins is at 37 weeks. Our doctor doesn't believe there are any indications of early delivery at this point, so we're looking at 37-38 weeks most likely, unless something changes really quickly. That puts us anywhere between Feb 5 and Feb 19th. We'll know more after the next ultrasound on Jan 29th.
At this point, the main issue is keeping Lisa comfortable. The babies like to put their feet on her ribs and push as hard as they can to stretch out, which usually implies pushing their head into her bladder. Apparently, that's not really that comfortable, at least not for Lisa.
If you get the chance to see the documentary "In the Womb: Twins, Triplets and Quads" on the National Geographic Channel, by all means, watch it. It was a fascinating look at what is going on in there. A little scary for parents to be at times, but comforting as well. It's amazing to see how much of the basis for the relationship between twins is formed before they are even born.