marsdaydream answered your question: Omegaverse Headcanon Question Time!

can you say more about how pregnancy works in this universe, the precautions omegas take – how does birth control work?

Hmmmm, pregnancy.

There is birth control, and it works just as well for omegas as it does for women.  There is not, however, any really functional method to suppress heats.  It’s a subject under research by drug companies, but to date, any drug powerful enough to contend with the chemical craziness going on inside an omega’s body during heat was pretty likely to fuck them up royally.

So, omega conception:

Omegas are fertile only during heat.  In fact, ovulation technically begins about halfway through.  It’s not auto-pregnancy.  Their chances of being impregnated are higher with an alpha than a beta, and higher with a beta than a fellow omega (omega sperm count tends to be very iffy).  The more times an omega has sex in heat, the higher their chances of pregnancy are.  If they sleep with multiple partners, the chances of impregnation are lower than if they only sleep with one partner multiple times (there’s all kinds of crazy science involved in how different men’s sperm competes in RL).  The best chance of conception—and it is very high, but not definite—is by having sex with a single alpha partner all the way through heat.  The colloquial term for this (and rather derogatory in a ‘filthy sex talk’ kind of way) is ‘being bred.’  And yeah, it’s kind of a kink of John’s.

Carrying the baby:  I figure that when an omega actually conceives, their body undergoes further changes.  Like a pregnant woman, their ligaments soften a bit, providing extra flexibility for their bodies.  I think their hips must spread, to enable the baby to fit through the birth canal.  

Possibly omegas normally have a subtle hip flare; it wouldn’t be all that noticeable in their proportions unless it were particularly exaggerated, since their rib cages and shoulders are broad like a male’s.

Birthing the baby:  yep, ass-birth.  Considering how flexible the channel has to be in order to be able to take a knot, this is probably pretty self-explanatory.

Precautions:  Like I said, birth control is available to most omegas in the industrial world.  It is magically reliable!  XD  Because I don’t feel like dealing with real-world things like the fact that sometimes these things just, hey, don’t work that time.

Omegas don’t have to have sex during heat, but it’s a truly miserable experience if they don’t.  Using toys on themselves mitigates it somewhat, but there’s some kind of pheromonal play involved between live sexual partners that makes toys never quite satisfying.  An omega does not need to have sex with an alpha, either.  A pretty decent workaround is to have sex with another omega.  Omegas are only indifferently fertile, sperm-wise, at the best of times (your average male testosterone count would do a lot of damage to a pregnancy, but is needed to foster virility in a male).

Incidentally, alphas, betas, and omegas are all susceptible, to varying extents, to an omega in heat.  Alphas get hit the hardest, and are the only ones who go into rut, but betas get really damn turned on, and even other omegas find it alluring.