Homozygous carriage of a 14 base pair (bp) insertion in exon 8 of the HLA-G gene may be associated with low levels of soluble HLA-G and recurrent miscarriage (RM). We investigated the G14bp insertion(ins)/deletion(del) polymorphism in 339 women with unexplained RM and 125 control women. In all patients and patients with secondary RM after a firstborn boy, 19.2% and 23.9%, respectively, were G14bp ins/ins compared with 11.2% of controls (p