Celestia had unfortunate effects on the nerves of most ponies, even five years into retirement, but medical professionals got it worst. Something about confronting the idea of her having imperfect health made things so much more difficult for them than for spa workers or waiters. Doctor Flowering Branch was doing pretty well so far in Celestia's estimation. Better than the nurses and receptionist had done, certainly. Dr. Branch's ocean blue mane wasn't frizzed from panic, and she hadn't sweat through either her seafoam fur coat or her white cloth one.
Which wasn't to say she that wasn't cowering on the other side of her desk like a foal facing a reprimand from her principal.
“Please, have a seat, er, your Majesty?”
Celestia offered a gracious smile to the doctor that would hopefully offset any awkwardness that her decision to sit down on the floor between the two guest chairs might cause. Cozy as this particular doctor's office was, the chairs were severely undersized for her frame. The doctor cringed but, encouragingly, didn't whimper in despair or babble about back-orders like the poor mare in the lobby had.
It was hardly their faults, but saying anything, no matter how kindly, would only throw it into sharper relief. Yes, most places in Canterlot went out of their way to make sure they had something on hoof for her. And, yes, sitting on the floor was hardly the most comfortable way to conduct a meeting. But after a thousand years of apparent chastity and abstinence, any fair minded pony ought to be able to forgive a fertility specialist for not expecting her, of all ponies, to make an appointment.
Better to change the topic entirely. Try to make the mare more comfortable by setting a ground rule for her to hold onto. The title, perhaps. Getting anypony to simply call her “Celestia” was still like pulling cragadile teeth, but they should all know that Twilight and Cadance were the “Majesties” by now. Every little bit of reinforcement in that direction helped.
“Please, you don't have to call me that anymore, Doctor Branch. I'm just Celestia now. Or 'Princess', if you'd prefer.”
“Oh, er, yes.” A fraction of Dr. Branch's tension bled away to make room for an equal measure of a doctor's confidence. “Of course, er, Princess. Is there anything you'd like before we get started?”
Celestia's smile broadened ever so slightly.
Gotcha.
“No, thank you. I'm quite eager to hear your thoughts on my issue.”
To her credit, the doctor didn't blush at the prospect, instead drawing on a little more of her reserves of professionalism.
“Of course, Princess. I've… ahem, I've had a look at your file, and your description of the problem. And, well…”
Celestia's smile growth neatly reversed itself. Dr. Branch looked uncomfortable as she shuffled her papers into some sort of order with her magic. Uncomfortable in a far more professional sense than before. Then again, she'd never actually gotten “bad news” from a doctor before. Not for herself. Perhaps she was making a maulwurf out of a mole.
Dr. Branch eventually set the papers down in a neat stack and looked up. “I have a few questions I'd like to ask you to help me narrow things down.”
“Of course.”
“With regard to your age. Er, I know that our standard form only gave you three digits to work with. Could you give me a more precise value?”
“How precise do you need?”
“Er,” Dr. Branch rubbed a hoof against her opposing leg. “Within a decade? If you can?”
Celestia nodded. “I believe I am somewhere in my 1,170's. Probably between 1,172 and 1,174.”
“You're not certain?”
“It was somewhat difficult to keep track of time during Discord's reign. It's one of the reasons I eventually reset the calendar entirely.”
The doctor's eyes and mouth both went round for a moment before she caught herself. “Yes. Yes, well, that's certainly close enough to help.”
“I'm aware that age plays a role in fertility, but I've not changed significantly since my late twenties. Every other medical examination I've had has remarked on that.”
“Er, yes. Yes! Yes, that was all in-- in your file, yes.”
Too much. She'd probably come across as questioning her expertise rather than… what had she meant by that? Looking back, that'd almost sounded defensive. Dr. Branch was cringing again and those files had to be completely out of order by now.
Celestia straightened up. This would not do. She was here to be told not to tell.
“Doctor, I must confess something to you: I'm not very well versed in medicine.” The doctor rocked back in her seat, shocked by her bluntness, no doubt. “I'm somewhat behind the times in a great deal of scientific knowledge, in fact. I've always made sure to surround myself with knowledgeable ponies to help me manage policy, as there was never enough time for me to learn it all for myself, but that has never been more necessary than in the last century. I've come here for much the same reason. If I make any wrong-headed assumptions, please, do not hesitate to correct me, and certainly don't take my word as the final one.”
She swallowed. Would it be too much to say more? The doctor still looked nervous, but a more personal plea might make her uncomfortable. Then again… Branch was a doctor in a very personal field. It might be what she was used to. She ducked her head slightly.
“This is important to me, doctor. I don't want to miss out on this because I'm doing something wrong. If you think my age is important then, please, ask your next question.”
Dr. Branch glanced down at her files, then back up to Celestia. “I'm not sure, Princess, but most of the patients I see who are having this much difficulty conceiving have something conspicuous in their medical history. An injury, a past bout of a disease that can impact fertility, symptoms of a hormone imbalance, something like that. Your age is the thing that leaps out at me as the one thing you don't have in common with most mares. Er,” a slight pink tinge crept into her cheeks, “besides your size, I mean. And, er…”
Celestia's smile came back, just a little. “Being an alicorn?”
“Er, yes. But with Princess Cadenza's success in mind, I really think we should start with your age. I have a few questions that weren't covered by the, er, volumes of your older medical history that I could get my hooves on, if that's alright?”
“Ask anything you like.”
“Have you… ever tried before?”
“No.”
Branch's eyebrows shot up. “Never?”
“Never intentionally. I… did have a close call once. An accident, if you will. But nothing came of it.”
“How long ago was this?”
“Five hundred forty nine years ago. I remember the date quite clearly,” she added in answer to the doctor's obvious incredulity. “For better or worse, it was a memorable event.”
The doctor visibly went back and forth with herself, then shook her head and set her jaw with determination. “Forgive me, Princess, but I'm afraid I'm going to have to be very direct with you about this if we're going to get anywhere.”
Here we go. Much better.
“Please.”
“How long have you suspected that you've had a fertility problem?”
“Just in the last two years.”
“You had no reason to suspect anything during the last millennium?”
“No, I did not.”
“…How?”
“A solemn vow. One that I finally fulfilled five years ago. And one that I only failed to uphold on a single night, five hundred forty nine years ago.”
Branch's ears drooped. “Oh. And… after that night?”
“I made use of what options were available at the time to prevent a pregnancy and counted my blessings when my next cycle hit.” Like a train, as she recalled. Not that they'd been invented yet. It was as if her body decided she needed to be punished for her indiscretion in the pettiest way possible.
“I-- I cannot even imagine the self control you must have.”
Celestia chuckled. “Oh, you get used to it. I hardly ever thought about it anymore after the first few hundred years.”
Branch snorted. “I didn't make it to twenty!”
Celestia perked up. “You have children?”
And there was the blush. Hesitantly, Branch turned a picture frame on her desk around in her magic. A little photograph of herself snuggled against a rather charming looking pegasus stallion, surrounded by five adorable colts and fillies ranging from foal to preteen.
“Oh, my. I see I came to the right doctor.”
The photo whipped back around, much to Celestia's amusement, while the doctor tried her best to get her decorum back.
Gotcha again!
“Anyway. About your cycle. Have you noticed anything unusual about it? Late or early starts, missed cycles, extreme variations in intensity?”
“All three. I've always been irregular. My past doctors put it down to stress, but I haven't looked into it any further than that until now.”
“Always?” Branch looked her straight in the eye, all business once more. She really was handling herself quite well. Luna's recommendation was looking better by the minute. “Are you sure?”
The word 'yes' was on the tip of Celestia's tongue when it paused at the jump. She had been, hadn't she? Stress was a very well known cause for such problems, even back when she was up to date on medicine, and she'd always had a stressful life.
But then again…
For all the irritation that a mare's cycle could bring, it was a routine irritation. Memory filtered routine like ears filtered the background noise of a busy city, and it was so very long ago. But surely she could recall her first time going through it? Luna would still have been a filly at the time, of course, but when she was older…
“No. I don't think I am. I… No,” she said, more firmly than before. “I was regular at first. My sister and I would always hit ours at nearly the same time, living together like we did. Then, after she was gone, I-- I stayed mostly regular. I was under a lot of stress at the time, but I leveled out after a few years.”
“When did that change?”
Celestia's wings ruffled. When? It must have been centuries ago for her to have so fully forgotten.
“I want to say… in my sixties? No, seventies? I'm sorry, but I just don't remember.”
“That's alright, Princess. That's close enough.”
“Is it important?”
“Maybe.” Papers rearranged again; Celestia was starting to suspect a nervous tick on Branch's part, but this time seemed a touch more purposeful. “I know I saw it in here… aha! Here we are!” A single page leaped triumphantly above the rest. “Let me see… it says here that you use a few prescription grooming products for ponies with excessive shedding?”
At last it was Celestia's turn to flush. “Ah, yes. I have quite a bit more fur to manage than the average mare, and my mane and tail can be rather troublesome at times.”
Branch's smile was warm and reassuring. “I understand, Princess. I never would have guessed if it wasn't in your files. You also molt your feathers, yes? And have to keep your hooves trimmed?” Celestia nodded to both. Branch slumped as if a great weight had just landed on her back. “I was afraid of that.”
These were rather odd questions. The excessive shedding she could understand perhaps being a sign of an underlying hormonal problem for anypony else. But molting? Not excessive or irregular molting, but simply molting, period? And hoof trimming? What was the connection?
“I don't wish to question your expertise, again I'm not well versed in this area, but how are my hooves and feathers related to my fertility?”
“What you've told me is that your body is still… aging, in a way,” Branch told her desk. “Your feathers and the hairs of your coat are still growing, wearing out, and getting replaced, which suggests that your biological processes are running at the same rate as any other pony. If that's true, then… I think I know where to start.”
A cold knot balled up deep in Celestia's stomach. She couldn't mean-- no, no the math didn't work out. She was no doctor but she wasn't ignorant.
“I know a mare is born with all of her eggs already formed, but we have many hundreds of thousands of them, don't we? I couldn't have-- surely I still-- I mean, I'm not that old!”
Branch's hoof pushed a sheet of paper a little to the left, her eyes staying resolutely down and away from Celestia's while she answered. “The actual number can vary anywhere from the tens of thousands to the millions, but the average mare is in the range of five or six hundred thousand at birth. One is released per cycle so you'd expect a mare to still have hundreds of thousands by the time she hits middle age. But… that's not how it works out.
“You see, for every egg released, many more just… die. The average mare might only have a thousand eggs left by the time she reaches the end of her foaling years. Maybe less. Every medical metric we have says that you're a mare in her late twenties or early thirties, but I don't know why or how you've stayed that way. If your cells are still aging and dying at anything close to a normal rate like it seems, and your apparent overall age is because your body is just really good at replacing them, then I'm afraid that--”
“How do we find out?” Celestia rasped.
Branch's head ducked lower, ears pinned back hard. “There's a test. We--”
“When?”
“I ordered the lab to start setting up as soon as you arrived. They should be ready for us by now.”
Celestia's knotted stomach followed the rest of her to her hooves under strenuous protest.
“Lead the way.”