AIBU to say no to being my step sister's birth partner?

No, it's not fair to say yes if you feel unsure. I've been a birth partner and it's harder than giving birth yourself IMO! There are obviously some issues if she doesn't want her partner there, and you don't want them blaming you for anything that might happen.
And it's better to say now so she has lots of time to plan-be honest, your own family are planning to be away.

This thread is hard to read with all the deletions but I would do this, even for someone I wasn't particularly close to. She is your step sister, you share a sibling - that's family. I'd see it as an opportunity to strengthen bonds or just to help out a woman in a tricky spot who wants the support of a someone who's given birth herself and will advocate for her.

@WayAhead I think I would just say you wouldn't be able to give her the support she needs during such a time as giving birth and she would be better with a close friend

That is a lot to ask if you’re not close. Tell her you have commitments with your husband and children. It doesn’t sound like you see much of each other so she won’t know whether you have things on or not.

It’s funny that she and this bloke are comfortable enough to have sex but not have him at the birth of their child. It’s not your problem OP.

Ignore the usual posters who are happy to volunteer others.

I would tell the truth and that it requires a really close relationship which you don’t have. If that is too honest then just say you are really busy with kids, work and your holiday so you can’t do it.

I was the birthing partner for a close friend but I wouldn’t have done it for anyone else.

I think it’s a bit cruel to turn her down but if you do I would say something like you really struggled for Dsis births and would really prefer not to do it again. Rather than your not my real sister.

I did it for my sister but refused when my half sister asked me. We are not close and it felt too much for me.

If you work, then just say you’re overwhelmed with work and with the holiday as well, you can’t commit.

Girl? Presumably she’s a woman. It’s awful that you’re trying to make the OP feel guilty. I hope OP isn’t feeling guilty because she shouldn’t.

This is a hard one for me. On the one hand you have no obligation to be a birth partner to anyone if you don’t want to, on the other I couldn’t reject it. It’s such an intimate thing, she chose you because clearly she trusts you more than friends/your sister etc.

I was once in a very similar situation, it was a girl from my university course that was having a baby and while we were friendly, we were hardly best friends. I was so confused and honestly weirded out when she asked me, I didn’t feel all that comfortable with it but I agreed because she asked and felt she could trust me on such an important matter. It turned out her relationship was ending, he had been abusive, she had moved away from her friends for him, her parents/siblings didn’t give a flying fuck and she didn’t have anyone she could trust, she asked out of desperation. She was so relieved that she wouldn’t be alone and had someone there to support her.

It was one of the best decisions I have ever made, that baby is my god son and the young woman is one of my dearest friends.

Here is what I’d be considering in your shoes:
Why is her partner not going to be present?
Is her/your mother still around?
Any obvious reasons she wouldn’t ask a friend?
Why aren’t you close?
What is her support network like?
Are you the most capable person to do it?
What would it cost you not to do it?
Could this bring you closer?

Edit: forgot a couple of words.

How sad. I think I would do it because the poor girl feels close to you even if you don't feel the same way. I would do it for a stranger tbh.

It's a big ask, wanting someone to drop everything - including work - to support someone throughout a labour that could go on for hours and hours. Days, even.

I'd expect it to be a very intense situation , for a first time mother without a partner.

I understand why she'd ask you, as a mother of two who's supported your own sister through two labours. However, it's ok to say no, you don't feel comfortable taking that on anymore.

This isn’t your problem OP. She has chosen to go ahead with a pregnancy to someone she hardly knows and doesn’t feel comfortable enough with to support her. It’s his baby, not yours and you’re not obliged to be there. You have said you’re not close and don’t want to do it so don’t be made to feel that this is your problem to solve.

She must know you are not close, yet hasn’t worried about your comfort here. Tell her the truth which is you don’t have that sort of close relationship.

I think it would go down much better if you tell her the real reason though. Does it really matter if your sister finds out now that you were anxious for hers?

The other reasons make it sound like you don’t like your step sister enough to be there for her or to re-arrange your holiday for. The actual reason is far less unreasonable less hurtful for the step sister.

I think if you explain to her that when you did it for your sister you found it really hard and it made you very anxious that would probably be an easier conversation. Nobody wants an anxious birth partner!!

Could you have a chat with your sister to see if she’d be there for her? So you could always suggest that as an alternative?

You probably need to have the conversation pretty soon because if she’s due in October she’ll be very pregnant already!!

Could you tell her that you felt overwhelmed with anxiety in the run up and during your sister's birth. You had a difficult birth yourself and it brought back memories of that. So you feel that you wouldn't be the best person to help her

Also so say that you will be on holiday... and it would be stressful for her relying on someone who might not be in the country when needed so she needs a back up plan and someone who can commit to being available for that whole period.

I don't think its exaggerating, it's seems to be at the back of what you have been saying in your posts.

However, I think she's going for familiarity so she may still keep asking. It's very sad for her I guess.

well, you've done it before, twice, so the point is you don't WANT to do it. which is fine, she's an offspring of your parents partner, you don't have to consider her family.

perhaps tell her that you have trauma linked to your own birth experiences and really struggled through your sisters but don't feel it's something you can do again. don't tell her you could but just don't love her so won't

Yes you could tell her that you didn’t feel comfortable the last time you were a birthing partner so you don’t want to repeat the experience.

Also, you mentioned the stress of your own birthing experiences. Maybe you could say you’re not keen to relive it all.

"Sorry I can't we're going in holiday in October"

I wouldn't do it either. Tell her that you've thought about it but it's not something you're comfortable with and that you also don't want to commit to it because you are going on holiday.

It is her choice that she doesn't want the father there, it isn't your responsibility to fill that gap.

No I wouldn't want to do it either OP. Personally I would've hated having a birthing partner for myself but they were (I think) unheard of in the 70's when I had my son. It's the most intimate thing imaginable. Will she have someone at home after the birth?

This, I can’t imagine turning down anyone desperate enough to ask me. Have some compassion OP.

I would hope I would hold the hand and try and be supportive of any woman giving birth even if I wasn’t close to them because it’s scary and I wouldn’t want them to feel alone.
I wouldn’t want to be down the business end but after having 3 of my own children which included a traumatic delivery I feel like I’d probably be more useful in the room then a bloke she doesn’t feel comfortable enough to see her at her most vulnerable.