Likutei Moharan 229:1/ליקוטי מוהר"ן רכ״ט:א׳

1Know! certain [types of] trees, when made into [wood for] beds, are propitious for bearing and raising children. The opposite is also true: there are those that are not propitious….

2This is hinted at in the verse, “The man kept asking about us and our birthplace” (Genesis 43:7). And it is brought in the Midrash: He even told us about the wood of our beds (Bereishit Rabbah 91:10). For, as explained above, the wood of the bed affects the favorableness of the conditions for childbearing.