There has long been established an interrelation between gum diseases and a risk of premature birth – unhealthy gums are one of the factors that tip the scale to cause early labor. Untreated gum diseases were found to increase the risk of labor starting before due time by three times. Full story

Yes, when something goes not quite according to the book during the first trimester, it increases the risk of the mother having a premature child. The European Society of Human Reproduction and Embryology (ESHRE) had a paper delivered at its annual meeting to the effect that if mothers suffered from certain complications during the first three months of pregnancy, premature labor may ensue. Full story