The Playdate by Louise Millar

Callie and Suzy live across the street from each other in London and became friends when Callie rushed Suzy to the hospital to have her twin boys. Callie's daughter Rae and Suzy's son Henry, are the same age and attend the same school.  Suzy, an American, is a stay-at-home mom married to Jez, while Callie is single and looking to going back to work, now that Rae (who has a heart condition) is in better health. Nonetheless, Callie worries constantly that just playing like a regular kid might endanger Rae. It's soon evident that Callie's and Suzy's friendship is based more on loneliness than shared interests or affection, and when a new neighbor, Deb, moves next door to Suzy, the cracks begin to appear.  Told through the eyes of all three women, the reader is immersed in their lives--yet they are unreliable narrators who are probably keeping secrets.  In The Playdate, Millar writes a debut where the reader slowly peels the layers to reveal surprising truths.  A novel that would appeal to people who like psychological domestic novels and the writers Sophie Hannah and Nicci French.