CD40LG and rubella: Still, a few studies have measured rubella-specific IgM in pregnant mothers, finding 5% positive in Pakistan (Ahmed, 1992), 1.1% positive in Japan (Okuda et al., 2008), 0.3% positive in Tanzania (Mwambe et al., 2014), estimating that rubella affects somewhere between 0 and 5% of pregnancies globally.