Why is water birth eligibility governed by BMI rather than total weight?

[Badgeretta]

I've always wondered this. I believe many trusts will decline water birth if the woman has a BMI over 35, based on the potential for difficulty lifting her out of the water if necessary. But a 4'10" woman with BMI 35 will weigh just above 13 stone, while a 5'10" woman with BMI 34 will weigh 19 stone (rough figs). Why are they happy to lift 19 stone but not 13 stone?
Why not just have a weight, ie 16 stone or something, and not bother taking height into account at all?

Because it’s increased BMI which gives you increased risk factors when giving birth.

anyway, 13 st at 4’10 is still pretty large.

This.

Also BMI more than absolute weight will affect ability to monitor the foetal wellbeing, and the woman's ability to get out of the pool quickly if the shit is hitting the fan.

I always wondered this. If it's because high BMI is generally more dangerous then this is at odds with what tends to be said. I was told it was because you may have to be lifted out the water. I wasn't too heavy by the way, I'm not touchy about it.

High BMI also likely to have an adverse effect on mobility

I would fancy my chances of successfully assisting a 13 stone woman who is 5' 10" in getting out of a bath but suspect i would struggle with a 5' woman of the same weight

As a high BMI mother I have had 2 waterbirths at home and 1 advantage of water is being able to quickly change position myself without help. If I had been on land and needed to flip over I would have needed help to avoid falling off the bed.

Ah it makes sense if it's about how easy it is for the woman herself to get out under her own mobility. I had thought it was about lifting out someone unconscious/unable to help themselves 🙈

The weight is a risk factor for your body in childbirth. It’s nothing to do with them being able to lift you.

It is about monitoring baby in water and about how you would get out in an emergency. As I have personally been in this situation and read the policy. It's about a whole picture though and although I'm fat, I'm fit and had no weight related pregancy problems, no GD, high blood BP etc etc. Very good mobility. I did have to fight for my birth plan though.

However, everyone has the right to birth how they want and you can chose to go against guidance. My birth plan was water even though I was BMI of over 40. However, my baby was 2 weeks overdue and there were complications that led to an emergency c section. So it never happened.

Some of the responses here really make me despair. Higher BMI is not a health condition in and of itself. A woman with high BMI might have an increased risk of developing certain health conditions, but it does not mean that she will develop them. Similarly, with regards to mobility, a higher BMI woman may have better mobility than a woman with lower BMI. And due to the way BMI is calculated, a woman with high BMI may weigh less than a woman with low BMI.

Your health care should be assessed on an individual basis, holistically taking into account your own personal well being, and not lazily relying on what is normally recommended. Access to things like birth pools cannot be restricted simply due to BMI. You have the right to birth where and how you want. You can ask to speak to the lead midwife and have an individual risk assessment performed, taking into account the weight limits of safety apparatus such as hoists that would be used to get you out of the pool in the case of a medical emergency.

Dr Sara Wickham has written an excellent book on the subject called Plus Size Pregnancy, which examines the evidence around raised BMI in pregnancy and your rights. I would highly recommend giving it a read.