**2.1 Conditions for screening**

First question is what we want to find? Which disorders are mostly indicated in pregnancy and what is really danger for pregnant women. Former studies resolve problems, which laboratory parameters are the best for investigation, the sampling of blood from pregnant women timing and also applicability of commonly used reference intervals for each parameter (Lazarus & Premawardhana, 2005; Poppe et all., 2007). Iodine supplementation is also usually asked (Glinoer et all., 1995).
