Mod version
Last updated
January 09, 2021
The Sims 4
Game Version
Overview Files Requirements Issues Changes Development
Cycle is a mod for the game "The Sims 4"

Cycle adds menstruation and woohoo risk as problems your sims must deal with. Trying for babies is no longer so easy, and having a night of ecstasy with your partner is no longer so safe. Use caution to avoid unwanted rug rats or carefully track your sim's fertility in order start a family.

Note: This mod plays best with long or even paused lifespans. Those of you who enjoy playing with many generations of sims; this mod is likely not a good match for you.


  • Adds a nuanced simulation of the menstrual cycle to sims who should have one.
  • Adds negative moodlets that can appear when a sim starts their period.
  • Pregnancy can now only start if a sim woohoos while fertile.
  • Teenagers can now get pregnant through their 'mess around' interaction if they are not careful.
  • Regular woohoo is now dangerous, sims must now buy protection, avoid woohoo on fertile days, or risk it with the withdraw method.
  • Condoms, birth control pills, pregnancy tests, and morning-after pills are all available to be used by your sims.
  • Allows your sims to get pregnant and leave who the real father is a mystery to you. (Increase pregnancy length to better experience this feature) (Better support for this coming in the future)
  • Use the cycle tracker phone app to keep track of fertility and menstruation.
  • New items that both have special functionality and work well as decorative clutter.

Features Coming Soon

These features are planned to be added very soon.
  • Miscarriages could occur randomly through bad luck or by your sims doing actions harmful to their baby's health. This feature will support the mod Basemental Drugs.
  • Abortions will be available to have done by a doctor. I also want to make it so that players can set whether or not abortions are legal to have for sims living in certain neighborhoods, simulating real life abortion laws varying by state and country. Places where it's illegal would require sims to take risky action to abort their pregnancy.
  • Birth control pills will require a perscription from a doctor.
  • Teens will be more restricted in their ability to acquire birth control pills and abortions. They would have to ask their parents if it's okay first to avoid punishment. Parents might not allow their teens to do this so getting an abortion or birth control pills might require some sneaking around.
  • Sims who have slept with multiple partners around the time pregnancy began shouldn't automatically know who the father is. In the future, babies will not list their father if the mother doesn't know who it is. A paternity test would be required to find out the truth.
  • Teens will have to admit to their parents about their pregnancy and risk punishment.
  • Pregnancy isn't always something you wanted, so sims shouldn't be forced with a moodlet that declares how happy or excited they are.

Supported Mods

Note: That a this mod supports another mod is not an endorsement or recommendation of that mod.

  • Wicked Whims by TURBODRIVER - Cycle has a decent amount of support for Wicked Whims. This mod's "woohoo" and its items work with Cycle. I don't typically play with one and won't always know if the compatibility breaks, send me a message if a new version isn't working.

Incompatible Mods

View incompatible mods

Questions and Answers

Q: Can I install this mod without having to start a new game?
A: Yes! You should be able to install this mod at any point in your play-through without issue.

Q: How easy is it to remove this mod? Will uninstalling it break my save game?
A: This mod can be easily removed by deleting all its files or using the mod's included uninstaller. Removing this mod mid play-through should cause no issues.

Q: Does this mod contain adult content? Does it fit within the teen rating of The Sims 4?
A: Unless your the type of person who thinks safe sex and menstruation is inappropriate, you will find this mod is completely pg-13.

Q: How do I buy woohoo protection?
A: You can buy such items with a computer, just go to the order menu and select "Purchase From Protect Tech". Alternatively, If your living off the grid or just don't own a computer, you can order woohoo protection buy mail using a mail box.

Q: How do I know when a sim is fertile?
A: Download the Dot Period & Ovulation Tracker app to the phone of a sim who has a menstrual cycle and select the "show cycle status" option.

Q: How can I adjust long a menstrual cycle should last?
A: Click any sim and go to NeonOcean > Cycle > Mod Settings. Once you've entered the mod settings dialog go to Time Settings > Reproductive Speed.

Q: How many days should I set cycles to last for?
A: Generally, I recommend setting it to as long as you think you could be bothered to wait for. I think about 8 days is the best mix of not having to wait for ever and not having a sim's fertile window be too short.

Q: How short could I reasonably make a cycle last?
A: All though you are allowed to go to about as low as 1 day, I do not recommend less than 3 days. At around 3 days or less, you will start to experience some issues. For example, your sim's periods might be too short for the effects to actually appear. If you elect play with such short cycles, the use of quick mode basically required in order to have the any possibility of pregnancy.

Mod Links

Documentation -
Sources Repository -

NeonOcean is reliant on people like you to not starve, and also, to continue working on and improve her mods. You will also get some nice stuff from helping out, such as early access to new versions.
Support NeonOcean ❤️

This mod is reliant on one or more other mods to function, check the requirements tab to download these.

Installer (Windows Only) Temporarily disabled
An executable to automatically place this mod in The Sims 4 mod folder. You would want to use the installer if you want to expend minimal effort to setup this mod. It can do some nifty stuff like uninstalling any old versions, and automatically enabling mods if you wish. This can currently only run on Windows computers.
Files (Manual Installation)
The mod files contained in a zip folder. Download this if you would like to install the mod manually or you can't use the installer. If you need assistance installing this mod, a guide can be found in the mod's documentation.
The source code and other raw files used to make this mod. You should only download this if you know what you are doing.
If you would like to download outdated versions of this mod you can do so here:
Previous versions

Required Mods

Incompatible Mods

  • MC Woohoo by Deaderpool - This causes the try for baby interactions to not consider fertility. Normal woohoo works as intended, but use of the risky woohoo setting will likely cause this to break too. This mod would be supported right now, but the creator felt the need protect their MOD FOR THE SIMS 4's source code as if its a big government secret.

  • Slice of Life (Menstrual Cycle Module) by kawaiistacie - You only need to delete the menstrual cycle module, everything else should work fine. Leaving the menstruation module in will cause your sims to have two cycles at once. Nothing is lost by using this mod instead, the Slice of Life version is relatively simplistic.


This mod has no known bugs.

Reporting Issues

If you are experiencing unexpected problems with this mod you can report your troubles via this mod's Github page. Be sure to check the mod's documentation to learn the proper procedure for reporting bugs.

Bug reporting guide

Change Log

v1.3.1 (January 9, 2020)

  • Fixed support for WickedWhims, it should now be compatible with the latest version.

v1.3.0 (December 12, 2020)

  • Cycle and pregnancy lengths are now set by the number of days it takes. The previous way seemed to confuse some people.
  • Added support for Main's new bug reporting feature.

Fixed Bugs

  • Fixed issue where changing the amount of time a pregnancy takes causes all sims to falsely appear like their going through a pregnancy.
  • Fixed incorrect sperm arrival percentages for withdraw failure.

v1.2.0 (August 19, 2020)

Minor item improvements

  • Added more detail to the condom box and pregnancy test textures.
  • Fixed shading issue on the pregnancy test item.
  • Gave a fake brand name to the pregnancy tests.

Item purchase interaction

  • Changed the item purchase interaction name on the computer and mail box to reflect the fact that not just contraceptives are being sold now.

v1.2.0-beta.1 (August 9, 2020)

Emergency Contraceptive Pill

  • A one use item that temporarily delays the release of a sim's egg cell in order to buy time for sperm in their system to die off.
  • Sims should take this pill as soon as possible after an accident in the bed room, in order to prevent accidental pregnancy.

WickedWhims Support

  • It is now not possible to select any other pregnancy mode in the mod 'Wicked Whims' than 'simple'.
  • WickedWhim's 'Check Cycles Info' interaction is now disabled by Cycle.

Fixed Bugs

  • The take pregnancy test interaction now works correctly on toilet stalls.
  • The game's take pregnancy test interaction no longer appears after trying for a baby.
  • Pregnancy tests and birth control pills no longer show up in the build / buy menu.

v1.2.0-alpha.5 (July 17, 2020)

Birth Control Pills

  • Can now be purchased in the purchase contraceptives menu.
  • The effectiveness of the medication slowly increases the longer a sim is on the pill. It is advised to use additional protection during a sim's first cycle after starting the medication.
  • The built up effectiveness can be quickly lost if you forget to have a sim take their medication for too long.
  • Use of birth control pills also gradually reduces the severity of a sim's menstruation. This can get to the point where it becomes extremely light or appears to stop entirely.


  • A certain percentage of sims will be randomly selected to have to endure premenstrual syndrome (PMS).
  • PMS will start a short time before menstruation begins and carries negative and positive moodlets.
  • Those going through PMS can experience bloating, fatigue, mood swings, and cramping.
  • PMS can be manually enabled for specific sims through a setting in the new sims settings menu.

WickedWhims Support

  • WickedWhim's birth control pills object are now recognized by Cycle and function as they should.

v1.2.0-alpha.4 (July 10, 2020)

  • Copied improvements from v1.1.3 release to the development branch.

v1.2.0-alpha.3 (July 6, 2020)

Dot Tracker

  • Sims can now opt to receive notifications when ever they become fertile.

Other Changes

  • Copied improvements from v1.1.2 release to the development branch. (WickedWhims support now added)

v1.2.0-alpha.2 (July 2, 2020)

  • Copied improvements from v1.1.1 release to the development branch.

v1.2.0-alpha.1 (June 29, 2020)

Pregnancy Test

  • Added new pregnancy test object. Pregnancy tests now (optionally) require a pregnancy test to be purchased before hand.
  • Pregnancy tests now longer give happy or sad buffs, they only show simple notifications. This works better for this mod since it is now possible to become pregnant accidentally. Sims shouldn't be necessarily be sad they didn't get pregnant from a one night stand, nor should they be necessarily happy if they did.
  • Taking a pregnancy test will no longer jump a sim's pregnancy progress forward after taking a pregnancy test, like it does in the base game.
  • Pregnancy tests can now be taken at any time, not just by sims who recently tried for a baby. They can also be taken by people who can't normally get pregnant by try for baby interactions.
  • Tests can now return false results, especially when taken very early into a pregnancy.

Quality of life improvements

  • Notifications now appear when a sim runs out of condoms.
  • Notifications also appear when two woohooing sims have a noticeable failure of their birth control methods.

Other Changes

  • Box of condoms price, 100 > 75

v1.1.3 (July 10, 2020)

Fixed bugs

  • Fixed strange issue in which missing sim statistic trackers would prevent the mod from saving.

v1.1.2 (July 6, 2020)

WickedWhims Support

  • Cycle now has basic support for the mod "WickedWhims". I don't understand why some of you like this mod. I've added support because many people seem to want it and some are just ignoring my warnings about the two mods being incompatible.
  • "Woohoo" interactions added by WickedWhims now add sperm to sims.
  • WickedWhims's period system is now disabled and replaced by Cycle.
  • Cycle's condoms boxes must be unpacked before they can be used with WickedWhims's interactions.

v1.1.1 (July 2, 2020)

Performance Improvements

  • Improved load times in heavily modded games.

Fixed bugs

  • Changing whether or not a sim should use condoms will no longer cause minor loading errors.

Other Improvements

  • Added system to try to always remember which sim is which, even if another mod goes and changes their sim id.

v1.1.0 (June 24, 2020)

Fixed bugs

  • It is now no longer impossible to get pregnant after saving once.
  • The pregnancy time setting can actually changes things now.
  • Pregnant teens now receive the pregnancy moodlets and correctly physically show their pregnancy.
  • Reproductive systems and dot information are now correctly load data when loading a game from the main menu.
  • The dot cycle tracker app can now exit out of pregnancy mode.

v1.0.0 (June 19, 2020)

  • Initial release


Dot App

  • Allow the app to send the player notifications when a sim is fertile. (By patron request!) (Available in patron preview version!)

Mod Support

(Let me know about a mod you want Cycle to support. If I know many people want Cycle the support a certain mod then it increases the likelihood I will add such support.)

  • Basemental Drugs, doing drugs should negatively impact fetus health, it should even cause miscarriages.

New Items

  • Birth Control Pills (Available in patron preview version!)

    • Would greatly reduce the chance that a sim ovulates.
    • Can cause periods to be lighter or even stop.
    • Purchasable only after getting a prescription from a doctor, settings should allow this requirement to be disabled.
  • Plan B

    • Delays ovulation to try to prevent pregnancy.
  • Pregnancy Test (Available in patron preview version!)

    • Replacement for the simplistic interaction on toilets (Which doesn't currently work well with Cycle).
    • Pregnancy tests would no longer increase the pregnancy progress like it does in the base game.
    • Would allow you to test without required your sim to have tried for a baby recently.

Pregnancy Buffs

  • The game has pregnancy buffs always make the sim happy. This doesn't work when accidental pregnancy becomes a possibility. Pregnancy buffs should at least apply a neutral mood effect and not exclaim how happy a sim is about it.
  • What a sim feels about their pregnancy could be settable by the player. (By patron request!)

Manual control

  • Sims could have different levels of manual control, specified by the player.
  • The mod could refer to a certain sim in the second-person (uses "you" to refer to the sim instead "him/her/they").
  • Sims chosen to be manually controlled by the player wouldn't do some things automatically, like remember to take their birth control pills.
  • This feature would be good for players who like to focus on one or two sims in a household.


  • Sims would be able to get an abortion at a hospital.


  • Pregnancy could end in an miscarriage randomly a certain percentage of times. (It should be possible to disable this)
  • Certain actions could increase the likelihood of miscarriage.

Area Laws

  • Things like birth control and abortions could be illegal or hard to get depending on what neighborhood you live in.
  • Abortions could be obtainable through other, potentially dangerous means.
  • Area laws should be changeable through settings, the laws would be realistic but not everyone wants to deal with it.

Unknown Parents

  • Babies' family trees shouldn't list a father if there are more than one potential father.
  • Babies of cheating sims should list the mother's official partner as the father, even if they are not.
  • DNA testing could allow for the discovery of a sim's the true parents.