Looks like Ekta mayi is using the Kahavat that "There will be 7 people who look alike arround the globe. And unfortunately we know science to certain extent which tells the genes are responsible for resemblence. So here comes the logic, the humshakal is the benami daughter of MA's father )who would have used and thrown the lady or would have ducked out of his responsibility to give this girl a name and shelter in the society). All her anger is routed towards MA who was enjoying all those facilities, name & position etc which was robbed from this girl. So she waited for so long to take revenge on MA and now to defame MA and to spoil her Image, she took steps to kill the unborn child (like they say, children will have to pay for the mistakes of parents)
Jaya