Notably, IENFD and TrkA nerve fiber density increased in HF from week 2 (IENFD: 33.4 ± 3.1, TrkA: 25.6 ± 3.2 fibers/mm) to week 4 (IENFD: 39.4 ± 1.2, p = 0.004, TrkA: 30.4 ± 1.8 fibers/mm, p = 0.001) (Figures 3A,B). This evidence concerns the gene NTRK1 and hydrops fetalis.