Experiments using either Tgfbr1 floxed allele gave similar phenotypes, but while Tgfbr1flox/-;Cdx2CreERT+/0 embryos required two consecutive tamoxifen doses at embryonic stage (E) 6.75 and E7.25, a single tamoxifen injection at E7.25 was sufficient to obtain the same mutant phenotype from for Tgfbr13ex3-flox/-;Cdx2CreERT+/0 embryos, thus reducing the frequency of tamoxifen-derived late fetal miscarriage. Here, TGFBR1 is linked to spontaneous abortion.