Antibirth adds a few new types of pickups.
Hearts
Immortal Heart
Immortal Hearts are white hearts which append to the end of the health bar like soul hearts.
Immortal Hearts always take two hits to be fully depleted, and will regenerate from half to full upon clearing a room.
Rotten Heart
Rotten Hearts are infested red hearts which fill up a full heart container. If a Rotten Heart is picked up at full health, it will replace the rightmost red heart.
For each Rotten Heart possessed upon clearing a room, two blue flies will spawn. A Rotten Heart is depleted in one hit, however under certian circumstances you can have half a rotten heart. After you start taking a full heart damage from enemies, if you get damaged with a Rotten Heart next to half a red heart, the rotten heart will be damaged to half, instead of being destroyed fully. A half Rotten Heart spawns only one blue fly, and grabbing half of a regular red heart will "repair" it.
Depleting a Rotten Heart will not count against Devil Deal Chance when it's the rightmost red heart.
Rotten Hearts are unlocked by entering the Corpse for the first time.
Pills
Three new pill effects were introduced in Antibirth.
| Pill | Effect |
| Experimental Pill | Increases one random attribute and decreases a different random attribute. Will not decrease attributes with PHD. |
| Shot Speed Down | Decreases shot speed. |
| Shot Speed Up | Increases shot speed. |
Notes
- It is possible for an Experimental Pill to decrease health while Isaac has one heart container, killing him.
Runes
Multiple new runes were added to Antibirth. When on the ground, these runes look like: 
| Rune | ID | Icon | Message | Unlocked by completing | Effect |
|---|---|---|---|---|---|
| Rune of Gebo | 60 |  |
"Charity" | 4x. Bloody Mary | Donates to a machine or beggar |
| Rune of Kenaz | 61 |  |
"Pestilence" | 2x. Scat Man | Poisons all enemies in the room |
| Rune of Fehu | 62 |  |
"Wealth" | 3x. Turbo | Turns all the pickups in the room into coins |
| Rune of Othala | 63 |  |
"Legacy" | 9x. Seeing Double | Rewards a random item that Isaac already holds |
| Rune of Ingwaz | 64 | "Treasure" | |||
| Rune of Sowilo | 65 | "Renewal" |
 Bosses
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 Challenges
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 Chapters
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 Characters
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 Items
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 Monsters
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 Objects
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 Pickups
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 Trinkets
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 Unlockables
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