(A) Number of pups delivered in WT, Hz and KO females. ZP4 ablation significantly impaired fertility: only one female out of 10 delivered a small litter of 4 pups, whereas ZP4 haploinsufficiency (Hz) did not affect fertility. (B–G) ZP4 disruption did not affect ovulation (B), cleavage (C) and blastocyst (D) rates, preantral (E) and antral (F) follicles counts or pronuclei formation rate (G). The number of females (A–B), embryos (C-D and G) and slides (E–F) analysed per group is indicated inside each column. Data are represented as mean ± SEM in all graphs. Statistical differences are based on ANOVA (p<0.05, (A–D) or t-test (p<0.05, (E–F). (H) Representative images of zygotes obtained from WT or KO females showing normal pronuclear formation (SYTOX green staining) in the presence (WT) or absence (KO) of ZP4 in ZP.