Maternity leave as a postdoc

[Goose4]

Hello,
I've recently found out that I'm pregnant (currently 7 weeks, due February 2020). I am employed full-time by a university as a postdoc on someone else's grant (funded by a UK Research Council). The grant is due to end in November 2020.
I have not yet told my boss or HR that I am pregnant (I'm waiting until at least 12 weeks), but I was wondering if anyone had any experience with accessing maternity leave in this situation?
I am eligible for the university's mat leave as I've been employed for over 12 months, but that policy says I'd need to go back to work for at least three months after the end of my leave. So, I would need to return to work in August 2020, which is earlier than I'd like. Based on what I can find on the RCUK website, it may be possible to extend the grant a bit to cover my period of mat leave, so I may be able to take a bit longer?
I suppose I'm not quite sure exactly what I'm eligible for, nor how to approach HR about it as the dates don't all work out nice and neatly.
If anyone has been in a similar situation, I would love to hear about your experience!
Sorry for the long post :-)

What should happen in this situation is that university should pay your full maternity leave (this does not come from the grant but should be from a central university budget). This means that the grant should have extra funds for the PI to be able to hire maternity cover or to ask for a no-cost extension and give you more time to come back. Some universities don't have the funds in place for maternity pay to come from a different pot of money, but they should and you + your PI should fight together for this if needed.

It is then your PIs choice about what to do for maternity cover and/or extending the grant. The plan will obviously depend on things like: what is happening on the rest of the grant and whether there is anyone who could replace you for a short time. But when you tell your PI, if you can make it clear how much you are keen to come back and suggest how it could be feasible to extend the grant, then a supportive PI may be able to 'pause' the project to give you more time to come back.

Obviously, if your project is run to a tight timetable (e.g. data must be collected in March 2020 or the whole project fails), then the PI will have to get cover in and there will be less time for you to come back. So that is up to a negotiation between you & your PI, and the funders will then have to approve any changes to the grant spending.

Depending on how the conversation is going, you could also introduce the possibility of coming back part time in August 2020, if the grant can't be extended. I've done that for postdocs sometimes. HR don't like it, because it can look a bit like you are managing someone out if they return on a reduced contract, but if that's what the woman wants it can be possible to make it work. That frees up a bit more money for replacement (because a 7 month postdoc is a pretty rubbish job for whoever takes on the cover).

As a PI, my instant preference would be to ask the funder for a no-cost extension, though. Grants are always pushed for time, and it's glorious to get a few extra months for no effort!

Thanks so much for your responses, @parietal and @ommmward!
My boss (one of the Co-I on the grant) is likely to be very supportive (she had bad experiences going on mat leave when she was a postdoc and I'm pretty sure she'd not want to do the same to her own postdocs), so I think I'm going to tell her soon after my 12-week scan just so that there is a lot of time for planning and sorting out maternity cover!
Thanks again---I really appreciate you taking the time to answer!

I think this is wrong. If your university has a policy that you have to go back for 3 months after maternity leave to keep additional maternity pay (I presume this is it), they can't make you do that at a date pre 12 months post the start of maternity leave just because of the grant end date. If the grant ends midway through your maternity leave, that's the university's lookout and you don't have to pay back additional maternity pay! You may well want to see if the grant can be extended to enable you to return and complete your part of the project, but that is a separate issue. I have been through this scenario.

I'm going on maternity leave in Jan 2020 as a post doc, I've asked for a no cost extension to the grant from my funding body (the Royal Society, UK). So my contract will just be extended by the amount of time I take off :)

Hi @Goose4 I started a similar thread because I'm in a similar position now, due feb 2021!
Can I ask how it turned out? What was arranged?