Steady Pregnancy Progression Mod: Incredible Pregnancy Changes for The Sims 4

Steady Pregnancy Progression brings smoother belly growth, unique pregnancy lengths, and customizable changes for a more natural Sims 4 experience.

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The Steady Pregnancy Progression mod from SonozakiSisters is getting a complete remake, and it brings a much smoother way for pregnancies to develop in The Sims 4. Instead of having a pregnant Sim’s belly noticeably change only when they enter a new trimester, the mod now makes those changes happen gradually throughout the pregnancy.

The remake keeps the original feature where a Sim carrying multiple babies has a larger belly, but it adds plenty more customization and realism on top of it. The result is a pregnancy system that can feel much less predictable and much more unique from one Sim to another.

Pregnant Sims Now Get Daily Belly Changes

One of the biggest changes is the new daily belly progression. The belly size gradually changes every day instead of jumping between trimester-based stages, with the update taking place at 4 AM so players are less likely to notice the change happening. It applies to both played Sims and NPCs across the save.

The progression can also begin during the hidden pregnancy period by default. That means players can actually notice a visual change during the early stage of pregnancy instead of having to wait until the regular trimester progression kicks in.

And yes, the original multiple-baby feature is still here. Sims carrying twins, triplets, or more can have a larger pregnancy belly than Sims carrying a single baby.

Every Pregnancy Can Have Its Own Length

The mod also makes pregnancies less predictable by giving each pregnancy its own individual length. For a single-baby pregnancy, the basic range is between 87.5% and 112.5% of the original pregnancy length, and that base length can also be changed through MCCC or Wicked Whims.

The range becomes shorter as the number of babies increases, meaning pregnancies with more offspring can naturally be shorter. Because the length is determined individually, one Sim carrying one baby could even have a shorter pregnancy than another Sim carrying twins, adding a little randomness to each family story.

Belly Sizes Stay Consistent

SonozakiSisters has also rewritten the belly size function directly to prevent the size from unexpectedly resetting. According to the creator, the belly should now remain consistent even when Sims are posing for photos or being viewed in Create-a-Sim.

The Update pregnant belly size cheat is still available, although it is intended for specific situations where the normal system does not update as expected. For most pregnancies, the new system should handle the belly progression automatically.

Customize Your Perfect Pregnancy Belly

For Simmers who love tweaking their gameplay, the remake adds much more control over belly progression. The mod includes several preset templates for different numbers of babies and trimester stages, using the same values that were available in the creator’s previous mod.

These presets can now be customized. For one baby, two babies, three babies, and more, players can set values between 0 and 1 for each trimester, as long as each trimester’s value is higher than the previous one. The hidden pregnancy value should remain at 0, and players can experiment with the settings to create their own preferred progression.

If you change the values during an existing pregnancy, you may need to toggle the trimester back and forth for the new belly size to appear. The creator notes that MCCC pregnancy cheats can be used for this.

There is also an Enable / Disable Steady Progression for Hidden Pregnancies cheat within the Steady Pregnancy Progression category. This lets players decide whether the gradual belly progression should happen during the hidden pregnancy period.

Steady Pregnancy Progression Works With Popular Pregnancy Mods

The remake is compatible with MCCC, Wonderful Whims and Wicked Whims, Relationship & Pregnancy Overhaul by Lumpinou, Realistic Childbirth by Pandasama, and other pregnancy mods that do not override the belly size function. However, players can only have one mod installed that changes pregnancy belly size.

For the smoothest results, SonozakiSisters recommends using a longer pregnancy duration. The default Sims 4 pregnancy is only three days, with one day per trimester, plus the hidden pregnancy period. At that default length, the belly progression can still feel similar to the regular trimester progression, so the creator recommends setting pregnancies to at least six days or longer for more noticeable gradual changes.

Installation Requirements and Compatibility

Steady Pregnancy Progression is base game compatible and requires the Lot51 Core Library. The mod should be placed in the Mods folder no deeper than one subfolder, and players need to choose one belly size preset. The creator also specifically warns not to delete the JSON data file.

Players using Lumpinou’s Relationship & Pregnancy Overhaul will also need SonozakiSisters’ special compatibility injector. The mod conflicts with other mods that alter pregnancy belly size, so checking the creator’s compatibility information is important before adding it to an existing Mods folder.

Final Thoughts

Steady Pregnancy Progression looks like a great option for Simmers who want pregnancies to feel less like three sudden stages and more like an actual gradual process. Daily belly changes, individual pregnancy lengths, multiple-baby adjustments, and customizable presets give players plenty of ways to make pregnancy gameplay fit their own storytelling style.

The mod was shared as a preview by SonozakiSisters on July 31, with the Patreon post noting a public release of August 21. If you’re building a more detailed family gameplay save, this is definitely one to keep an eye on as the release approaches.

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