(Y/N) and Magnus decide to have another baby, but sorry it'll be like before, but that desire is stronger than their fears.
Warning: sexual content

(Y/N)'s P.O.V.
Watching my child grow up has been an adventure. It's different raising a hybrid; add how their dad is Ultra Magnus. It's been rough figuring out the parenting balance. Our child is five years old, and though we agreed no more kids, I've been feeling the desire to have another. Even when I think how ridiculously overprotective Magnus was, the complication and pain, I want another baby. I'm afraid to bring it up to Magnus.

It's a great day with my child while Magnus and the other Autobots are on a mission. They eagerly await dad to come home and put them to bed.
"Daddy!" Our child cheers and runs up to him.
"Why are you still up?" He asks calmly.
"Bedtime story?"
"Ok, let's go," Magnus says and takes our child to their room.

Ultra Magnus' P.O.V.
How can you forget we can smell hormonal changes (Y/N)? Why are you embarrassed to tell me you need some fun?
Thinking of this reminds me of my damn heat cycle.
"Good night."
I kiss my child after I finished reading the story and go to my room.

"(Y/N), is there something on your mind?" I ask, hating she's worried and afraid, "what's wrong?"
This isn't good in a Cybertronian, human or mixed relationship.
"I...I know we decided (C/N) would be our only child, but ... I-I want another baby," she tells me, afraid, "I remember the complication and pain from (C/N)'s delivery, but I still—."
"Awe, baby; It's ok. You know I've been thinking (C/N) could use a sibling. Ratchet tells me every pregnancy is different. The next one could be a walk in the park. If you want to go on the journey again, knowing what we could face again, then let's try to get pregnant right now."
I pull her in for a kiss which quickly gets heated. We take each other's clothes off, and I push (Y/N) onto the bed.
My mind is thinking relief and hoping to get my girl pregnant.
She's already wet as I penetrate. As much as I want to pound her, I go slow at first, enjoying her moans of pleasure. I thrust for a few minutes before (Y/N) begs me to go faster. I watch her breasts bounce around as she moans in pleasure. I feel better and pull out and lay next to her.

Three weeks pass, and (Y/N) is throwing up. We both believe she's pregnant. Rather than get a pregnancy test, we go right to Ratchet, who confirms we're going to have a baby.

Our (son/daughter) is happy to get a sibling, though they don't understand why their sibling won't be here for nine months.
"I'm still worried about the delivery, but I'll try not to be overprotective," I tell her as we lay in bed.
"You know how our child leaves toys everywhere. I worry you're going to struggle to relax."

I talk with (C/N) the next morning, trying to get them to understand how leaving toys around is not safe. They leave their toys around, and it's not safe for anyone, but especially dangerous for (Y/N) now. Also, this is a good lesson for when the baby is crawling and grabbing things off the floor.
(Y/N) smiles as I talk to (C/N).

(Y/N)'s P.O.V.
Things go well; (C/N) loves coming to appointments and hearing the baby's heartbeat. The baby is developing well, and Magnus does his best not to be so strict, but there are still days I have to remind him to relax.

I didn't think Ratchet would ask me about the birth plan, suggesting I return to the base at thirty-five weeks since that's when (C/N) was born.
"(C/N) will love seeing the others as well," Magnus points out.
"Arcee can watch them during labor and delivery," Ratchet adds.
We agree five is too young to watch a baby be born.

Our child is eager to meet the baby and enjoys talking to my belly like their dad. Their reaction feeling the baby kick is cute. Magnus is struggling with not being overprotective as I get closer to the due date.

I plan on having our version of a home birth, delivering in our room at the base. Magnus is worried about this, and when I add, I don't want Ratchet right there.
"I think it's technically a hospital birth since the medbay is right there," I explain.

It's ten in the morning when I feel the first contraction. Magnus is happy it's early enough that we can get pain relief. Though I think he's going to struggle with the wait.
"At least this one flipped like they're supposed to," Ratchet comments, "labor just started; it's going to be a while."

I spend time with the others for the next four hours, but my pain is scaring (C/N).
"Your mom is ok," Optimus assures (him/her).
Not much you can say to a five-year-old about labor pain. Arcee takes (him/her) to play.
Magnus tries to let me decide when to get pain relief but also is trying to subtlety ask.

We go back to the medbay. Once Ratchet finds out I'm six centimeters, he too insists on getting the epidural now.
I walk around our room as we wait for Ratchet. My water breaks as he walks in. Even though he knows it's supposed to happen, it's embarrassing. Like he just caught me peeing...but I'm not wearing pants. I did need to remove my nightgown so Ratchet can get to my back. Funny, I'm nude and embarrassed, but I was nude the first time and not embarrassed. Guess excruciating pain is good for that.
The only way Magnus is letting me — hopefully— deliver alone in our room is if Ratchet sits in the hallway and waits with supplies.

Magnus'P.O.V.
I try to think even with the epidural; there's still pain. Though Ratchet says (Y/N) can be completely pain-free, but then she's not going to know when to push. Another four hours pass before Ratchet says she's ready, though I think her moaning tells us she's ready.
"Let her do this, Magnus," Ratchet says before leaving.

At least she's able to stand up and push. (Y/N) hugs me as she pushes for a few minutes.
"It's right there," she says, and I help her sit on the floor; doing her best to keep her legs open. Sure enough, there's the head ready to be delivered.
"Oh fuck, it still hurts," she pants as she pushes.
"That's it, baby, come on," I'm worried about delivering my child; a quick lesson earlier doesn't feel like enough, but I do as Ratchet instructed me and support the head, "almost there, push, baby."
This delivery is much faster, and (Y/N) isn't exhausted.
Ratchet does what he needs, and we help (Y/N) get on the bed to feed the baby. She rests for an hour before I wheel her out to the others.

"Baby!" (C/N) cheers.
"Do you have a brother or sister, (C/N)?" (Y/N) asks.
I whisper the answer for them to tell everyone.
"It's a (boy/girl)."
Everyone cheers resulting in a crying baby.
We laugh but know we need to get used to being quiet again.