Without considering the state of health of the carrier, what is the reason that a pregnant woman can't stretch herself to 44 - 50 weeks before her delivery phase would kick in? 
Or is it that a biological mechanism takes place that creates contractions and will set the whole labor phase in motion?
What would happen if these drivers would be suppressed? The vagina can take so much, so I'm not talking about the baby getting too big and ripping her all open. 
It's more about knowing that she can let her stomach grow further than usual 38 -40 weeks.

The fetus would grow and develop no differently than if it were born at the normal due date. For example, the fetus would begin to defecate, so there's the possibility of aspiration. Also, the placenta would shut down, starving the fetus of oxygen and nutrients. This whole thing is a bad idea.

(March 29, 2022, 5:36 pm)Feunski The fetus would grow and develop no differently than if it were born at the normal due date. For example, the fetus would begin to defecate, so there's the possibility of aspiration. Also, the placenta would shut down, starving the fetus of oxygen and nutrients. This whole thing is a bad idea.

Agreed.

Good and well informed replies. Basically when it’s time it’s time. The only exception would be when pregnancies naturally go overdue.

This is actually seriously bad.

When I was young, our neighbor went very very overdue at almost 46 weeks.

It was total hard-on enduing for me because every time I saw her, so kept getting bigger and bigger.
And she was no nice about it, like "baby will come when it's ready", or "almost here, just a little more waiting".


She ended up with an emergency c-section and almost died from blood-loss.

Not because the baby was huge, which it was very huge, but because past a certain time (around 42 weeks) the soft part of the skull starts to harden.
Once it hardens over enough, it's physically impossible to push out the baby, even if the baby is quite small.

This is why stories/fanfics/etc. that involve pregnancies >42 weeks annoy me. I like to imagine a scenario of a long and huge pregnancy as much as the next person, but it just becomes physiologically impossible at a certain point for the reasons others have already mentioned.

You would have to literally slow down fetal development in order to realistically imagine extending a pregnancy beyond its natural length, but I think that defeats the purpose you're trying to convey as that wouldn't necessarily make the woman bigger, just take longer to get to full term.

Ignoring the “suppressing” part of the initial post, how much longer could a woman realistically make it past 42 weeks if overdue?

Anything after 42 weeks puts the baby's health in danger so labor will be induced at that point if it appears the mother will not go into labor naturally. The good thing about fiction is the laws of nature don't have to apply. A story can explore suppressing labor longer than what is humanly possible and even allow a vaginal birth of a very large baby. I see no reason for an unrealistic pregnancy term to be annoying in a story. These types of scenarios are fantasies and I am more than willing to suspend my disbelief for a good 42+ weeks pregnancy story.

(March 30, 2022, 12:25 pm)BroHarrison This is why stories/fanfics/etc. that involve pregnancies >42 weeks annoy me. I like to imagine a scenario of a long and huge pregnancy as much as the next person, but it just becomes physiologically impossible at a certain point for the reasons others have already mentioned.

Once you personally go through a loved one nearly dying because the baby "didn't want to leave", you get annoyed seeing stories of women being pregnant for 2 1/2 years or naturally giving birth to a 20lb baby with ease.

My condolences to anyone who has suffered trauma related to overdue pregnancy complications. However, it does not mean that such stories are bad and should not be produced. Anyone that finds them annoying can simply choose not to read those types of stories.