Two short stanzas capture what it feels like to live with a baby. The first describes constant noise, "from morning till night a din," and the speaker admits it is both a trouble and a contentment. The sound wears on them, yet they wouldn't want it gone. The word "content" is quiet and settled, which suggests the speaker has made peace with the chaos, maybe even enjoys it.
The second stanza steps back and marvels. A "new mouth" is the source of all that racket, and the speaker finds it "strange" that something so ordinary, one more person who needs feeding and cries out, can still feel like "just another wonder." The phrase "just another" plays with scale: wonder is usually rare, but here it seems to arrive daily and still not lose its force.
The mood is tender, gently humorous, and a little tired. The poem is brief, like a snatched moment between cries, and it leaves us with affection rather than complaint.