SB 6.14.31
tasya anudinam garbhah
sukla-paksa ivodupah
vavrdhe surasenesa-
tejasa sanakair nrpa
Translation by His Divine Grace A. C. Bhaktivedanta Swami Srila Prabhupada:
After receiving semen from Maharaja Citraketu, the King of Surasena, Queen Krtadyuti gradually developed in her pregnancy, O King Pariksit, just as the moon develops during the bright fortnight.