Allele or haplotype frequencies of any of the studied polymorphisms, including AR CAGn, did not differ between SPTB mothers or offspring with or without PPROM, according to gender, or between individuals born very preterm (gestational age <32 wk) and moderately preterm (gestational age ≥32 wk) (data not shown). This evidence concerns the gene SPTB and preterm premature rupture of the membranes.