In 2007, 38 experts on bisphenol A wrote a consensus statement which said average levels in people are above those that cause harm to many animals in laboratory experiments. However, the experts noted that 1) BPA is not persistent in the environment or in humans, 2) biomonitoring surveys indicate that exposure is continuous, 3) it is hard to use acute animal exposure studies to estimate daily human exposure to BPA, and 4) no studies that had examined BPA pharmacokinetics in animal models had followed continuous low level exposures. The measurement of BPA levels in human serum and other body fluids suggests that either BPA intake is much higher than previously thought or that BPA can bioaccumulate in some conditions such as pregnancy, or both. A 2011 study, the first to examine BPA in a continuous low level exposure throughout the day, did find an increased absorption and accumulation of BPA in the blood of mice.