From HealthScout, C-Sections Linked to Higher Cavity Risk in Babies.
Li [the lead author] suspects that vaginally delivered infants, because of exposure to a greater variety and intensity of bacteria from their mothers and the surrounding environment at birth, develop more resistance to the cavity-causing germ than do C-section babies, who have less bacterial exposure at birth.
From MacLeans.ca, C-section linked with increased clot risk.
For vaginal deliveries, the odds of developing a blood clot were less than one in 30,000. But for caesarean births -- in which the baby is delivered through a surgical incision in the abdomen -- the risk increased to just under one in 1,800. Emergency C-sections came with a higher risk for blood clots than did elective C-sections.