The purpose of this multi-center trial is to evaluate the efficacy of IVIG in improving the ongoing pregnancy (\>20 weeks of gestation) rate in couples with unexplained secondary recurrent miscarriage, and; to characterize and compare pharmacokinetic and pharmacodynamic parameters for IVIG pre-conceptually and in the 1st and 2nd trimesters of pregnancy, so that an improved IVIG dosing strategy can be determined.
