The midwives

Exodus 1:15-21 -- "And the king of Egypt spake to the Hebrew midwives, of which the name of the one was Shiphrah, and the name of the other Puah: And he said, When ye do the office of a midwife to the Hebrew women, and see them upon the stools; if it be a son, then ye shall kill him: but if it be a daughter, then she shall live. But the midwives feared Elohim, and did not as the king of Egypt commanded them, but saved the men children alive.  And the king of Egypt called for the midwives, and said unto them, Why have ye done this thing, and have saved the men children alive? And the midwives said unto Pharaoh, Because the Hebrew women are not as the Egyptian women; for they are lively, and are delivered ere the midwives come in unto them. Therefore Elohim dealt well with the midwives: and the people multiplied, and waxed very mighty. And it came to pass, because the midwives feared Elohim, that he made them houses."

Does anyone know what this means, "[Elohim] made [the midwives] houses"?