While control embryos had RIs, PIs, and fetal heart rates within range of previously published values (Galaz et al., 2020), we found that trophoblast Cdh5 knockout embryos exhibited significantly increased RIs and PIs (Figure 3B–D) and significantly reduced fetal heart rates (Figure 3B and E), consistent with placental insufficiency and fetal distress. This evidence concerns the gene CDH5 and placental insufficiency.