The 'Immaculate Conception' does not refer to Christ's Conception but the dogma that Mary was conceived without sin by special grace, outside the inheritance of original sin. The dogma was pomulgated by Pius IX, and not without opposition.. to this day.
It is in stark opposition to the Marian theology devised by the Augustine and Thomas Aquinas, the greatest of the Church's doctrinal fathers.
You might refer to this story as a Virgin Birth.. but you should not refer to it as an Immaculate Conception.
I don't. Why should anyone refer to this nun's situation as a "virgin birth"? This woman was impregnated by a man. As they say, " It wasn't the Allmighty that lifted her nightie, It was Roger the Lodger, The cad". Or it could have been Father Smit.....the ****.