Of course, all that expansion means that you will need to buy new bras along the way, and unfortunately, there’s nothing available at the moment that will expand with you as you grow.
Your best bet is to buy well-fitted, high quality maternity or feeding bras, which will last long enough to be used after your baby is born, as you lose baby weight and start breast-feeding.
Have yourself measured and fitted by a professional, as this will give you the best fit and comfort – remember, you’re going to have back pain anyway during your pregnancy. It’s best not to make it worse by wearing an ill-fitting bra! Good maternity bras have wide straps and good support, although they’re not particularly sexy.