[Ruba-dub-bub]

Hi Ladies,

Had my morphology scan the other day. Baby is perfect and we are having another beautiful little girl

The sonographer said that they may just want to check the position of my placenta a bit later as it's 2.1 cm away from the opening. I didn't think that was bad as it's not exactly right near the opening....

I'm just wondering when they consider a placenta to be low lying? I assume this is why they may want to check it make sure it's a bit higher later ready for vaginal delivery?

Ta!

[cinnabubble]

I had a lowish placenta for my first. At RPA, where I delivered, the rule was 2cm away for vaginal births. It was 1.9cm away from the cervical os at 20 weeks. At 36 weeks, it was miles away.

They explained to me that the placenta is like sticking a postage stamp near the mouthpiece on a semi deflated balloon. Once the balloon inflates, the stamp stays stuck to the same place, but it's further away from the mouthpiece because the balloon has grown. I hope that makes sense.

[Corella]

Except that the lower segment of the uterus hasn't grown at 20 weeks so it's going to, and your placenta will move. Low lying placenta "diagnosis" annoys me so much because the basic physiology of a pregnancy means that it is MEANINGLESS to say that at 19/20 weeks.

In answer to your question - 20mm is considered close.

[Ruba-dub-bub]

Right so providing my uterus expands and strectches it up as predicted I should be good...? I really don't want another C-section if I can help it (DD1 was an emergency C-sect and I'm trying for a Vbac this time round).

I think I read somewhere that it will also depend on whether it's anterior or posterior as this can change the outcome??? I don't know which it is yet, I don't remember her saying...just that they may want to check it later.

I guess I always just assumed it was only ever an issue if it was covering the opening or right on the edge.

[SeaPrincess]

I had a low-lying anterior placenta diagnosed at my morphology scan with DS2. At that point, the radiology report stated that it was completely covering the internal os, but my OB told me he didn't consider it a praevia until we had gone past the point of it not moving. He did advise me as if it was a praevia though - told me what to watch out for and to get used to the possibility of a caesar.

I had some bleeding at 23 weeks and spent a week in hospital, but by 30 weeks, I got the OK for VB.

[Sassy Dingo]

Mine was 1.7cm at 20 weeks. At my 36 week scan it was 4.7 - so no worries.

Ob said as long as it was 2cm away it was ok for a vaginal delivery.

[mummyblossom]

My placenta was 1cm away at 20 weeks and obviously considered low lying. By 32 weeks it was 6-7cm away and even further at 36 weeks so it's not a problem at all any more. I believe the vast majority of low lying (especially where the placenta is not covering the cervix) 'move away' as the pregnancy progresses.

[soontobegran]

Exactly as cinnabubble has explained but there is nothing at all wrong with diagnosing a low lying placenta at the morph scan Corella because that is what it is and it draws attention to the fact that it needs to be observed more closely.
The diagnosis of a low lying placenta at 20 weeks is not an assumption that a C/S will automatically follow, it is all about knowledge and prevention of possible negative outcomes.

[Chief Pancake Ma...]

Its just so you can be flagged to have another ultrasound at 30+ weeks to make sure it has moved as there are no routine ultrasounds after the 20week one .

[Bunsen]

Except that the lower segment of the uterus hasn't grown at 20 weeks so it's going to, and your placenta will move. Low lying placenta "diagnosis" annoys me so much because the basic physiology of a pregnancy means that it is MEANINGLESS to say that at 19/20 weeks.

In answer to your question - 20mm is considered close.

Except in an uncomplicated pregnancy the morph scan is the last scan you have so it is entirely appropriate to note the position of the placenta at this point. Mine was flagged as low lying at the morph scan (1.9cm) so I have been referred for a another scan at 34 weeks, until then there are no decisions made re c-section etc, we just have to wait and see.