Immaculate Conception

Immaculate Conception is an unlockable passive item added in The Binding of Isaac: Afterbirth.

Effects[]

Upon picking up 15 heart pickups, Isaac gains a permanent angelic familiar and generates a Soul Heart drop. Possible familiars include:
All five familiars will spawn in a random order.
Isaac will look progressively more pregnant as he collects heart pickups.
The familiars spawned by Immaculate Conception will not contribute to transformations, such as Conjoined, nor do they count towards the collection page.

After all five familiars have been spawned, a Soul Heart will still drop every 15 hearts collected.
All types of hearts except Gold Hearts and Blended Hearts count.
Items that directly add health such as Yum Heart, Book of Revelations, Satanic Bible, and The Nail do not count towards spawning a familiar.
The Lost can pick up Soul Hearts and Black Hearts despite having no health and thus can activate Immaculate Conception.
Keeper cannot encounter hearts, thus the item is useless for him.
As the short-lived Half Red Hearts dropped by Tainted Magdalene also count, it is an excellent choice for her since she will constantly be picking up hearts and gain all five familiars quickly.
Familiars spawned by the item do not affect item pools, so multiple copies of one familiar can be obtained. For example, a second Seraphim can be purchased after Immaculate Conception spawns one.

Hypercoagulation: By intentionally taking damage with something like a fire and grabbing the half-red hearts, Isaac can easily generate powerful familiars for free.
The Jar: Hearts collected in the jar do not count towards activation.

This item is the angelic counterpart to Cambion Conception.
Immaculate Conception refers to the Catholic teaching that the conception of the Virgin Mary was free from original sin.