Q1:
Wait! Elven Biology thoughts. What do you think about elves and *cough* fertility? I'm perplexed on whether they get periods or not. Are elves fertile all the time? Do they have control over whether fertilization occurs? As they usually don't have children during times of war, but, not to discredit them, i'm fairly sure someone is going to be bonking. Do they just use contraception? What do you think?
Honestly I have thoughts about this ALL the time!!! Literally allllll the freaking time. I have two theories about how elven biology works.
Theory 1:
As we know human women are born with a preset of an 1 millions eggs. For that number to decrease by puberty to 300,000. The remaining eggs of course begin to deteriorate as we age.
It's entirely possible that either elven women are too born with an insane amount of eggs, and wouldn't have to naturally worry about their eggs aging because they're immortal and they don't age. Ovulating on a cycle but one that runs completely different compared to what a human woman would ovulate.
Their years and months especially in Valinor work much differently. Such as 1 year for them is the equivalent of 9yrs for us. So it's possible they have a cycle that happens every few ME years.
Theory 2:
Rather than being born with a preset of eggs like human women, their body makes their eggs instead on a cycle. That would allow for them to not possibly run out of eggs, keeping them fertile until the end of time essentially.
Which is to be expected considering that they don't age, they don't get sick so there are no afflictions that would cause them to lose their fertility. Of course outside physical forces could render them infertile.
So this would and could still give them a period that makes more sense for their bodies as opposed to the preset. Not to mention the eggs would still have to go somewhere. So either they're expelling them in the same way that human women do and have thousands of years experience to hide it perfectly and it's something very short lived. Or perhaps they don't have one at all.
Personally I think they'd have one, but because they're elves they're not nearly as excruciating as it is for humans, and they don't last nearly as long.
And as far as if they have control over fertilization, I think they have little to no control over when they conceive. The Eldar believe that children are a literal gift from Eru and their main purpose for having sex to begin with is specifically and only to have children.
Elves lose their drive to have sex (unless you're Fëanor) after they've had A child. I'd imagine if the drive picks back up, for them that's a cue more or less that they'd be more destined to have more than one child.
Many elves broke the Eldar rule about getting married during war time. That's what constitutes as being married is sex, a lot of elves had forgoed the traditional rules of waiting a year post engagement proposal to wed and a ceremony because of war time. So instead they'd just have sex and were viewed as married from then on out. The actual act of sex is what weds them.
I don't think they'd have used contraception, and have more or willing to hold out or have taken the risk. Tolkien was of course super old school catholic and if we look at what his line of belief was and compare it to his elves, it's pretty easy to say that contraception to them would be an absolute no no. Or wouldn't exist because preventing the creation of a gift from Eru would probably look extremely bad in the eyes of the Elves.
And it's safe to assume as well that there were plenty of elvish children who were being born regardless of the war. Especially early on far before times of peace when they were far more naïve and unaware of just how horribly dangerous this ordeal truly was.
Then we also have the years of peace after the intial arrival of the elves. Of course the elves were hyper aware Melkor was a threat but they also felt as things could only get better. That they had the upper hand and had grown comfortable in their times of peace and proceeded to not abstain any further!
Q2:
Was wondering what you meant when you said that an elven woman loses strength in relation to the child she gave birth to. Do you mean that in a permanent way or just temporary?
I can't remember where it's noted, but it's said that elven women are equal in strength to elven men until they get pregnant and give birth.
Their pregnancies are taxing compared to a humans in the sense of mind body and soul. Their fëa is said to nourish their childrens in the womb. Plus whatever else they are drawing on mom for. So they permanently lose strength with the pregnancy.
Elven pregnancies also last for a FULL year. 12 WHOLE months. I'm sorry but after being 4 days late with my daughter at 9months pregnant, 3 extra months would be miserable.
The average number of elven children in ancient times and in the First Age is between 3 and 4. And later on as the ages go on down to 1-2.
It's considered quite a rare exception that Nerdanel has 7 children. (But it's no surprise it is Fëanor)
Q3:
If elven pregnancies last a year; do u think a human mother's pregnancy would last that long?
As far as I know, a human mother carrying a Peredhel, their pregnancy wouldn't last that long. Tolkien I think would've mentioned it for certain if that were the case.
So I think their pregnancies are still just a regular ole 9 months! I'm sure there are extra taxing things that come with it with the child being half elven though!