In the play and the eighth book, Harry Potter and the Cursed Child, it suddenly turned out that Voldemort had a daughter, Delphine Riddle, and her mother was Bellatrix Lestrange. This twist raised many questions among fans: when did Bellatrix manage to give birth? Why were there no hints of pregnancy in the films or even in the books? Let's try to figure out when this could have happened.
When could the pregnancy have taken place?
By analyzing the chronology, we can assume that conception occurred in June 1997. Then Draco coped with his task, Dumbledore was killed, the Malfoys were somewhat rehabilitated after the failure in the Ministry. Perhaps, for the successful execution of the plan, Voldemort "rewarded" Bellatrix with his attention. If so, the birth must have taken place in March-April 1998, just before the events at Malfoy Manor, where Bellatrix tortured Hermione Granger.
This means that at that moment, the Dark Lord's main ally had just recovered from the birth. Perhaps that is why she behaved even more inadequately than usual. This scene can be seen in the film Harry Potter: The Deathly Hallows. Part 1.
Why is there no pregnancy in the books and films?
J.K. Rowling claims that Voldemort's daughter is canon and therefore not subject to discussion. Why then was it never mentioned anywhere? Perhaps she considered it inappropriate to add this moment to the pages of children's books.
There would be many questions about how the Dark Lord managed to conceive a child at all. With Bellatrix, everything is clear, she blindly adored her master, so she could have given birth to a dozen babies for him. But Tom Riddle never thought about women or heirs, dreaming of gaining immortality on his own.
Perhaps the conception happened by accident, and Bellatrix hid the fact of pregnancy from the Dark Lord. This would allow her to secretly give birth to a child from the man she loved. Or, which can also happen in the magical world, these are the consequences of some ritual and potions. In any case, Rowling did not reveal the details of such serious plot twist.
Summary
The timeline suggests that Bellatrix gave birth in March-April 1998. Most likely, Voldemort did not know about the child, and the pregnancy itself was hidden due to plot convenience. However, fans are still debating how logical this turn is for the canon.
