“Any tips on how to turn over at night? I'm having trouble from going from my left ....to my right.... to my left side,” she Tweeted.
Her message got over a thousand helpful replies, from mums to obstetricians.
The general consensus: sleep on your side and get a long pregnancy pillow for support. Other suggestions were to sleep in a recliner or take a rest on your back, mid-roll.
And, of course, many of her followers called for her partner Alexis Ohanian to just wake up and help her. Game, set, match.
Watch the video below to see Serena Williams chat about playing the Australian Open while pregnant!