No, I didn't have any complications with my guinea pig's births. Most of them were born at night, actually, apart from one of Opal's litters, which were born during the day when I was at school - but she had SEXTUPLETS - and I guess she just couldn't hold them until night, which is their preferred time, I believe. But apparently sextuplets are not that common, so we were quite lucky that Opal didn't have complications. It was quite a taxing pregnancy for her, of course - she was ENORMOUS by the end of it (I'll post a pic if you like...she looked like a little balloon), and she lost a lot of weight trying to feed six pups too, after they were born, as guinea pigs only have two nipples and the sextuplets constantly needed to nurse as they were so small (being part of such a large litter).
We still have two of the sextuplets, Hallie and Pyper. They'll always be small for their age but they still have a lot of guinea love packed into such small bodies!