Womb

The Womb is the fourth chapter of the game, unlocked after beating Mom. From the Womb onwards, all damage taken will do a full heart of damage to the player's health (unless the player has The Wafer), regardless of the source. Like Error: The given stage ("The Depths") does not exist./Necropolis/ Dank Depths, the Womb's second floor has a preset boss that will always be fought: Mom's Heart initially, and It Lives after beating Mom's Heart 11 times.

The Womb has two alternate floors. The Utero, which, unlike alternate floors before it, does not need to be unlocked separately from the Womb, and the Scarred Womb.

From this chapter onwards, floors do not include item rooms or shops, meaning that all item buying must be done before the player leaves The Depths/Necropolis/Dank Depths.

Monsters

Degraded Bosses
Envy Lust Sloth Wrath Blastocyst (small and medium) Chub Dingle The Duke of Flies Fistula (all sizes) Gemini Gluttony Gurdy Jr. The Haunt Larry Jr. Loki Mega Fatty Mega Maw Monstro Peep Pin Polycephalus

Bosses


Blastocyst	The Bloat	Daddy Long Legs	Lokii


Mama Gurdy	Mr. Fred	Scolex	Teratoma

			File:Boss The Headless Horseman.png
The Fallen Template:DevilRoomRequired	Conquest	Death	The Headless Horseman


Triachnid	The Matriarch	Sisters Vis

Double Trouble

Double Trouble Bosses


(Double Trouble) Dingle	(Double Trouble) The Cage	(Double Trouble) The Fallen	(Double Trouble) The Gate


(Double Trouble) Gurdy	(Double Trouble) Dangle	(Double Trouble) Little Horn

Final Boss

Mom's Heart will always appear in the second floor of this chapter or in the last boss room if Curse of the Labyrinth is active. Once It Lives is unlocked, it will appear instead of Mom's Heart.


Mom's Heart	It Lives

Notes

It is possible to access the Womb before unlocking it by using a Rune of Ehwaz or We Need To Go Deeper! on The Depths II.
Using the Rune of Ehwaz or We Need to Go Deeper on Womb/Utero II will lead the player to Sheol, which will skip any of Mom's Heart's endings.
The Womb being mentioned in Isaac's last will as a "warm place" is a reference to how the inner human body temperature is quite high.
The Womb and Utero both have a slight static filter covering the screen, possibly to represent heat.

Unlockable Achievements

Eden - Complete Chapter 4.

Pop! - Beat Chapter 4 without taking damage.

Mama's Boy - Beat Chapter 4 without taking damage.

Music

The music for the womb is titled Viscera. The term viscera represents the internal organs in the body. The Utero shares this same track.
The music heard during the fight against Mom's Heart/It Lives is called Ventricide. Ventricide is a word made up of the Latin word for Heart, Ventricle, and the suffix -cide, which denotes the act of killing.
- This has been confirmed by Edmund when he said it means something like "the killing of the heart". This is in theme with other similar boss tracks such as Matricide, Hericide, and Infanticide.

Binding of Isaac: Rebirth OST