Low BMI and natural birth

[wintersun21]

Hey guys,

Does anyone have any experience of giving birth naturally with a low BMI Pre-pregnancy my BMI was under 17 and I am a very skinny person! Worried about giving birth naturally because of this. I'm being monitored because of this but I'm having a massive mental block about whether to go for a C Section or whether I will be absolutely fine naturally

Having complications with the birth itself isn't a known complication for being underweight whilst pregnant. What has made you worried about this? Have you been able to talk to a midwife about this?

I have a bmi of 18 and have had 2 natural births; the only risk I was made aware of was a higher risk of tearing, but the midwives(/doctors) delivering will be aware of that. I did have an episiotomy with my first, but that was because he had a 99th centile head and suddenly needed to get out fast; with my second I only had very minor tearing. Nowt wrong with a c-section obviously but I’d question it if anyone is saying you’ll need one purely because of your weight.

So the big baby small mother worries are actually to do with the size of the baby’s head compared to the size of the women’s pelvis. - it’s the inside space in the pelvis that matters not the outside hip circumference.
Has anyone (medical) said to you that your low BM makes vaginal birth riskier? Maybe if you have super low muscle mass they might be worried but I can’t think of any other obvious issues (I’m not a dr/midwife). This is clearly worrying you, so do ask your midwife about it at your next appointment.

Sorry in case I wasn’t clear - losing or gaining weight as an adult with have no effect on the size of the inside of your pelvis. They don’t get bigger when you gain weight. So being underweight isn’t really related to that particular risk.

Do you have other reasons why you are being monitored other than low BMI? I ask because I was very skinny when I had my children (BMI of below 17) and I wasn’t monitored. I had normal vaginal births (although I needed an episiotomy with my first). All the babies were a decent weight, in fact my third was over 10lbs and his head was on the 99th centile!!
As a pp mentioned I think pelvis size is probably more of an issue.

Thanks guys, just to clarify I've had heart issues previous and had always been told that I would be fine to get pregnant although my weight may impact birth. Never thought much at the time but now I'm 23 weeks I'm just wondering what it means.

I have asked midwife but she just said that's something we discuss later on in pregnancy. I have my 24 week the week after next so I will raise it again then

Having had two c sections, the recovery is what it is. You have a guaranteed wound that needs to heal, plus issues with moving, bending, lifting to begin with. Some women will recover from that very quickly, some more slowly and some will have complications.

A vaginal birth doesn't have a guaranteed wound that needs to heal, nor so many issues with moving, bending, lifting. If you have no or only minor birth injuries your recovery is likely to be a lot quicker than a c section. Of course there is the risk that you might have a significant tear or other issues eg from an assisted delivery, but they are risks not a definite.

Given your specific circumstances with your heart issue I think you would need specialist advice from your midwife or consultant on whether a vaginal birth would have additional risks, or even if a c section might have additional risks too.

Why would you have childbirth issues due to being slightly under weight? It’s overweight that causes problems.