When does my sim need to get pregnant?

There's no way to know how long the elder stage will last. I had a Sim who had a baby right before her elder birthday; she died at his teen birthday party. There's no way to know if that will happen with yours or anyone else's, however.

An option: If you get the notice that your Sim is in her last days and you are not ready for her to go, you can take the potion that will put her back to the beginning of the elder stage.

Ok, thanks! That at least gives me some idea of how much time I have.

In my opinion the normal lifespan in the game is too short. At first my sims died of old age before their first child became a young adult. And my sims usually have their first child as a young adult.
You might set your lifespan on long. I tried that, but didn't like it. I could do loads of things, but it takes forever to raise the next generation. Instead I downloaded a mod by Darkgaia, "Tweaked Age Lengths", from MTS. IMO this mod balances the lifespan exactly right. If you don't mind using mods, you might try that. Then you could wait a little longer to start a family and live long enough to see your children start their own lives

I usually turn off aging until I'm ready to have my sim get pregnant. That way i can take my time having my sim work at her job, find love, or whatever else I want her to do before she has a kid and she won't age.

After reading the title I had to duct tape my own hands together and then sit on them because o god there are soooo many things I want to type but they would get me in trouble. :D

I usually play with long life-spans and some aging off. Which is why I have no idea how long a life span usually is. I'm going to try to play one family through multiple generations. I just don't want to be looking after too many sims at once so I'm happy for each generation to die as the next gets established.

@Sue_D_Nim lol I'm so very curious to know what thoughts you were having that made restriction by duct-tape so necessary!

"Sandun;13366942" wrote:
In my opinion the normal lifespan in the game is too short. At first my sims died of old age before their first child became a young adult. And my sims usually have their first child as a young adult.
You might set your lifespan on long. I tried that, but didn't like it. I could do loads of things, but it takes forever to raise the next generation. Instead I downloaded a mod by Darkgaia, "Tweaked Age Lengths", from MTS. IMO this mod balances the lifespan exactly right. If you don't mind using mods, you might try that. Then you could wait a little longer to start a family and live long enough to see your children start their own lives

I usually play on the long life setting and then I age them up to the next stage when I get ready too.

How to get a sim pregnant ...

well, there are a few ways. You have a daddy sim and a mommy sim ... and when two sims love each other very much, they have the ability to try for a baby ... they can try to have a baby in a few different places ... a nice double bed, an occasional observatory, a rocket ship .... and, after they do the deed the sims ....

to actually answer the OP, I normally wait till my sims are in the adult stage before getting serious about having a family. Most of the time the kid will age to young adult before both parents die from old age .... but even if they do not, teens can live alone. As others have said, you can buy the potion of youth to extend the elder stage

Depends if your Sim is male or female. Elder females can't have babies. I think adult and young adult are safe areas to start having kids and they should be the right age in time.

"Sandun;13366942" wrote:
In my opinion the normal lifespan in the game is too short. At first my sims died of old age before their first child became a young adult. ...

I agree ...
My first Sims Family had their first child at the beginning of their Adult-Stage.
They both died as Elders roughly a week before the Teen became a YA.

Even if we assume (as a comparison to Real Life aging) that the transition from Young Adult to Adult is at the age of 40 years, this would make its Parents just ~60 years, when Sims Child turns into a Young Adult ... which would either be just the beginning of the Elder Stage for its parents (if we assume that Elder Stage begins with 60 years) or even still within the Adult Stage (if we assume that the Adult Stage goes till 65 or even 70 years)