Superfetation — extra babies while pregnant

Superfetation lets a pregnant Sim conceive again mid-pregnancy.

Originally, the game only allows one pregnancy at a time with babies conceived at the exact same time. A new conception does nothing if the Sim is already pregnant.
This mod allows Sims to Try for Baby while pregnant, and if it succeeds, this mod can:

• Add Superfetation babies to the current pregnancy (born with them; the other parent can differ).
• Add Superfetation Premature babies if they're conceived after a certain trimester (configurable).
  • Or it can keep the pregnancy going after the original conception's babies are born, with the pregnancy already at an advanced stage (queued pregnancy mode, configurable).

How it works

By the mod's default settings, Superfetation babies join the current pregnancy along with the original conception's babies. Superfetation babies conceived after the second trimester (configurable) are born with the "Premature" trait (configurable), which slows down infant milestone progress and toddler skill gain. At birth, all babies are born together.

Alternatively, if you prefer the old Queued pregnancy feature, after the second trimester (configurable) a successful Try for Baby queues a follow-up pregnancy instead. A queued pregnancy has exactly the babies that were conceived during the third trimester of the pregnancy previously — the game does not roll additional babies on top. Since those babies were already growing, the queued pregnancy starts in the second trimester (also configurable).

Default superfetation chance is 5% for the first extra conception in a pregnancy, then 10% of the previous chance for each later success on that same pregnancy (5%, then 0.5%, then 0.05%, …). The count resets at birth or if the pregnancy ends by any means.

Taking a pregnancy test — or finding out without one — while already carrying Superfetation extras shows a Superfetation notification instead of the game's "Eating for Two!"

Household slots are reserved for Superfetation babies and queued follow-ups, so the household cannot be overbooked at birth.

The base game hides Try for Baby once a Sim is showing. This mod lifts that so Superfetation can happen in an otherwise unmodded game. An In-labor pregnancy still hides those interactions.

You can click a mailbox to open Superfetation Settings, or use the hnry.sf.menu cheat.

Chance and outcomes:
- Prone to Superfetation (Rewards store trait, 500 points): uses a higher first-extra chance instead (default 20%). A baby inherits it on a 5% roll if either parent has it.
- The game's own fertility boosts (Fertile, potions, fertility massage, On Ley Line, and the rest): change how many Superfetation babies a conception rolls.
- Superfetation extras roll gender with MCCC offspring gender percents at conception (or the live gender chance without MCCC). At birth, a gender you pick in Manage is kept; otherwise strawberries, carrots, Pop or Alternative apply the own game's baby gender sway; otherwise the conception rolled gender is kept.
- An in-labor Sim is skipped for automatic Superfetation; Manage add still works.

Late conceptions
Mailbox Settings has a Late conceptions picker: late conception babies stay on this pregnancy, or queue a follow-up.
"premature" is the new default (extras stay on this pregnancy; Premature trait from the second trimester). queued is the old follow-up pregnancy mode.
"Queue a pregnancy from" and "Queued pregnancy starts at" apply only in queued mode; they are unused in premature mode.

Requirements

• Script mods enabled
• Keep HNRY_Superfetation.ts4script, HNRY_Superfetation.package and HNRY_Superfetation.cfg in the same folder
• Optional: MC Command Center. Superfetation works without it. If MCCC is installed, its pregnancy-size and baby-gender settings are used instead of the base-game weights. MCCC's pregnancy menu shows and edits only the original pregnancy — Superfetation extras can only be edited on Superfetation Settings.
• Optional: Other mods that "take over" WooHoo or Try for Baby pregnancy are supported, but optional. Base-game WooHoo and Try for Baby work without them. If one of those mods is the one that starts pregnancy, Superfetation still runs when it succeeds while the Sim is pregnant.

Drop the three files in Mods folder (ts4script, package, cfg).  When updating, you can keep your existing HNRY_Superfetation.cfg. Fully quit and relaunch.

Cheats

• hnry.sf.menu — Opens Superfetation Settings (an active Sim must be selected).
• hnry.sf.status — Opens the Status dialog.
• hnry.sf.logstatus — Prints version, settings, and inject flags (include this or a screenshort of the Status UI when asking for help).
• hnry.sf.reload — Re-reads the cfg and retries injects.
• hnry.sf.enabled / chance / consecutive / pronechance / proneinherit / threshold / startstage / queue / mailbox_shift / litterboost — Get or set a setting (saved to cfg).
• hnry.sf.slots — Shows how household free slots are worked out.
• hnry.sf.clear — Clears Superfetation babies and queued pregnancies for all Sims (does not end pregnancies).
  Save your game after running the cheats.

Compatibility

If a pregnancy ends without a birth, Superfetation babies and any queued follow-up on that pregnancy are cleared too. A queued follow-up only starts after a real birth.

Disclaimer

This is one of my first attempts at Python coding/modding. The mod itself is liable to bugs, as most are. Please make a backup of your save before installing.

Support

For bug reporting or support please contact me on Discord @henryvotril

Thank you for using my mods! 💕