Labour has said a pregnant MP who reportedly faced a motion of no confidence in her constituency is not under threat, saying no such motion will take place.

Ellie Reeves, the MP for Lewisham West and Penge since 2017, faced the threat of a no-confidence vote after signing a statement criticising her party’s decision to readmit Chris Williamson.

But it is understood that the person in Reeves’s 2,000-strong constituency Labour party who proposed the idea has since confirmed they would not be formally moving such a motion.

The no-confidence attempt prompted fellow MPs to condemn the move, with the shadow health secretary, Jonathan Ashworth, calling it “ludicrous”.

The party subsequently said it would not take place. A Labour source said: “It would be wrong to bring a motion of no confidence against a pregnant MP who will soon be on maternity leave.

“No motion has been formally moved or tabled. And in any case, motions of no confidence have no formal standing and do not result in trigger ballots. Any MP who is on parental leave will not undergo reselection processes until they return from leave.”

Williamson was readmitted last Wednesday by a national executive panel that ruled he should only be reprimanded, although on Friday he was suspended again following a backlash that included the letter signed by Reeves and the deputy leader, Tom Watson, among others.

According to the website PoliticsHome, the email suggesting the idea said: “I would like to put forward a motion of no confidence in Ellie Reeves our MP for signing Tom Watson MP letter regarding Chris Williamson MP at our next meeting and also start the new trigger process to deselect our MP which you should have received from Jennie Formby.”

Reeves, who is 22 weeks pregnant, thanked Labour members for their support on social media after the news broke.

Miriam Mirwitch, the chair of Young Labour, said on Twitter: “MPs who are pregnant or on maternity leave should be automatically reselected. It’s wrong when bosses sack workers who are pregnant or on maternity leave. The same applies to MPs.”

Ashworth said on Twitter: “My friend Ellie Reeves is a socialist, an ex-trade union lawyer who fought against injustices for working-class people. She’s campaigned against oppression internationally, eg trade unionists in Colombia for years. An excellent MP. Ludicrous no-confidence motion should be binned.”

Plans to remove Williamson himself as the Labour candidate for his constituency are also being pursued by local party activists, the Observer reported.