Do you have to pay to get pregnant on second life

Yes and No.

Yes, if you want to use an in-world service or purchase items to help you simulate your role-playing as a pregnant person. This type of service includes a script that gives you bodily feedback, like morning sickness, feeling kicks, and having cravings. These appear as in-world text notifications on the screen. The service may also give you a series of "shapes" to wear that will give you the look of growing as you progress. Finally, these services can provide you with the doctor's checkups, ultrasounds, and of course, the birth procedure itself.

No, if you just want to "emote" the role-playing parts yourself and just pretend to be pregnant without all the visual aids. Anyone can pretend to be pregnant.