The only explanation given in Revenge of the Sith for Padmé's death is that because there is nothing wrong with her physically, she has lost the will to live after seeing Anakin turn to the Dark Side.
His only reason for turning to the dark side was a need to protect the ones he loved and to learn the secrets of preventing death. From Anakin's point of view, becoming Palpatine's apprentice was simply a way of becoming more powerful, and all the evil tasks he had to complete were to bring him closer to his goal.
Anakin does not have even the slightest bit of remorse. By the end, he feels nothing but anger. Although he feels regret for killing Padme, he still helps the evil Emperor. The film ends with Anakins standing side by side with the man on whose behalf he has committed all his crimes.
When Padme confronted her husband on Mustafar, Anakin choked her to unconsciousness out of anger. While the act alone didn't kill her, Anakin's turn to the dark side was too much to bear. Holding on long enough to give birth to her children, Padme eventually passed away, having lost the will to live.
Sadly the Clone Wars would have still happened, but Padmé would have also survived, giving birth to Luke and Leia who would have probably been inducted into the Jedi Order. As for what would have happened between the two, with their marriage and all, that's a bit tricky.
George Lucas Explains Padme's Death (NOT Palpatine)
Could Vader revive Padmé?
In the main Star Wars timeline, of course, Darth Vader's attempts to resurrect Padmé on Mustafar were doomed to failure. But it's fascinating to speculate what would have happened had he been successful. In that scenario, Padmé Amidala's return from the dead would not have provided the solace Darth Vader sought.
Although the droid specifically referenced Padmé losing the will to live as the source, over time, the narrative within the franchise and Star Wars audiences has become that Padmé died of a broken heart.
Amidala's body was taken to Naboo aboard Organa's ship, the Tantive III, and prepared by mortician Commodex Tahn, who made it look as if she had died pregnant. Her death was attributed to the alleged Jedi Rebellion that had prompted Order 66.
Honestly, I just couldn't figure out who she was or why she was even in the funeral procession. This also means that for the longest time I forgot I could just look up the credits of the film. Long story short, she is Padmé's niece, Pooja Naberrie, and was portrayed by Hayley Mooy.
The subtitles and script show some of Padme's final words to Obi Wan as “There is still good in him.” Every time I watch this I swear she says “Obi Wan... there's quite a name.” I have always thought of it as her recognizing him for everything he has done over the trilogy.
When Anakin had to choose between losing Padme — fearing that she might die in childbirth — or turning to evil to “save” her from death, he chose evil. His desire to “save” her at all costs led Anakin to the dark side. For him, the dark side became a means of saving his loved one.
Summary. Anakin Skywalker's murder of the younglings was fueled by his grief, self-loathing, and desire to save Padmé. Converting the younglings to the Dark Side was not an option because their loyalty to the Empire could not be guaranteed.
Why did Anakin think the dark side would save Padme?
He had emotional attachments to several other people, most notably his secret wife, Senator Padme Amidala. Anakin's desire to protect those he loved, like Padme and his mother Shmi, often led him to make questionable, if not outright horrible decisions that led him further down a dark path.
At some point after his transformation into the armored Darth Vader, Amidala's husband, the fallen Jedi Knight Anakin Skywalker came to visit the mausoleum, stricken by grief and remorse for his part in her death.
Star Wars confirms Obi-Wan Kenobi kept Luke and Leia safe by ensuring that one person missed Padmé's funeral: Padmé herself. The Star Wars galaxy was entirely unaware that the Queen of Naboo Padmé Amidala had given birth prior to her death - for a very sinister reason.
Ultimately showing the darker side of Anakin's love, his passionate nature leads him to care for Padme with all of his heart, far in excess of anything else in his life.
She died and the twins were split up, with Obi-Wan taking Luke to Tatooine and Bail Organa returning home to Alderaan with Leia. A generation later, the children of Anakin Skywalker would play key roles in overthrowing the Empire.
He had no idea Padmé had given birth before she died, still less that the Jedi had spirited the children away and hidden them. Darth Vader's illusions were shattered shortly after the destruction of the first Death Star.
Unlike in the movies, the Jedi Order would still be around to help each planet restore balance after their respective conflicts and to maintain peace in the years that followed. Palpatine's plan to install a Galactic Empire would come to a sudden halt and the Republic would be allowed to continue as it always had.
