Fig. 4: Acvr2b cKO mice are subfertile due to mid-gestation defects.

a–b Fertility assessment in the control (n = 10) and Acvr2b cKO (n = 10) mice over the course of 6 months. Total pups per month are plotted in a, while the number of pups per female per month is plotted in b. Data in b represent mean ± standard deviation, analyzed by single-factor ANOVA, p = 0.033. c–d Gross uterine images of 10.5 dpc implantation sites of control (c) and Acvr2b cKO (d) mice. Arrows in d indicate hemorrhagic and resorbing implantation sites. Red arrow indicates the implantation site analyzed by PAS in f. Size bar = 1 cm. e–f PAS-stained cross-sections from 10.5 implantation sites of control (e) and Acvr2b cKO (f) mice. Uterine natural killer cells (uNKs) are visualized as pink structures (indicated by black arrowheads) in the control implantation sites (e) but are absent in the Acvr2b cKOs (f). Abnormally expanded trophoblast giant cells are observed in the implantation sites of Acvr2b cKO mice (indicated by black arrows). g Experimental scheme used to induce artificial decidualization in control and Acvr2b cKO mice. g Gross images and quantification of the uterine horn weights after a 5-day decidualization. D, decidual horn; N, non-decidualized horn. i Decidual ratio was quantified by calculating the weights of the decidual horn relative to the control non-decidualized horn for each mouse. Images are representative of experiments performed in at least three subjects of each genotype. Histogram in i represents mean ± SEM. Unpaired, two-tailed t test, p = 0.40.