Wordnet polsko-angielski 
                         ( (pregnancy) the mucous membrane that lines the uterus
thickens under hormonal control and (if pregnancy does not occur) is shed in menstruation
if pregnancy occurs it is shed along with the placenta at parturition) 
endometrium 
Słownik medyczny polsko-angielski Iwona Kienzler
                        endometrium n
Nowoczesny słownik polsko-angielski 
                        błona śluzowa macicy