What is anterior placenta? How does it affect my baby's kicks?

And, for most pregnant women, all that having an anterior placenta means is that you'll probably feel your baby's kicks and movements a little later than a pregnant woman whose placenta has attached itself elsewhere.

What is anterior placenta exactly?

Your placenta is an organ that develops in your uterus (womb) during pregnancy. Its job is to provide oxygen and nutrients to your baby as it grows, and to remove waste products from your baby's blood.

Your placenta will develop once your fertilised egg implants in the wall of your uterus. And wherever your fertilised egg implants – whether that's at the top, the side, the front or the back wall of your uterus – that's where your placenta will attach.

Often, the fertilised egg will embed on the back of your uterine wall (meaning you'll have what's called a 'posterior placenta' – see our illustration below) but it's not uncommon for it to embed on the front of the your uterine wall instead, meaning you'll have an anterior placenta.

It's thought about 50% of pregnant women have an anterior placenta. Fascinatingly, having an anterior placenta seems to be slightly more likely if your blood type is O positive!

If you do have an anterior placenta, you'll probably first find out at your 20-week scan.

Is an anterior placenta normal? Will it affect my baby?

"The anterior wall is a perfectly normal place for the placenta to attach and develop," says Dr Philippa. And it will still nourish your baby just as effectively.

"It's important to know that having an anterior placenta is not the same as having a low-lying placenta or 'placenta praevia'," adds Dr Philippa. " That's where the placenta – either anterior or posterior – is lying very low in your womb and can be an issue if it's also covering the cervix."

If I have anterior placenta, when will I feel my baby's first kicks?

Most of us tend to feel our baby's first movements sometime between 16 and 24 weeks of pregnancy – more likely after 20 weeks if it's our first pregnancy.

But if you have an anterior placenta, you may feel these first movements a bit later than those who have a placenta elsewhere. It can help to focus on movements at your sides and low down, as this is where you are more likely to feel them.

"Your baby's first movements are rather fluttering sensations," Dr Philippa says. "Having an anterior placenta means that it may be a bit harder to feel them because your placenta is like a little cushion between your belly and your baby."

That was certainly the case for Jenni from our MadeForMums Community. "I had an anterior placenta," she says "and I didn't feel movement until maybe 24 weeks-ish but, by the time I was 28 weeks, he was kicking me and, from the outside, it looked like my tummy was dancing!"

If you haven't felt any movements by 25 weeks, though, do contact your midwife.

And also, once you have felt them and got to know their pattern, contact your midwife if you notice any changes. "Having an anterior placenta is not a reason to ignore any reduced movements." says Dr Philippa.

Is there anything else about anterior placenta I need to know?

"It may lead to some lower back pain," says Dr Philippa. "And your midwife might find it takes slightly longer to find your baby's heartbeat.

"It can also an make performing tests, such as an amniocentesis (which you may choose to have if your 12-week screening results indicate a high chance of your baby having certain conditions) more difficult for your medical team.

"But, if you're having an amnio, your doctor will always use ultrasound to check everything first – so, even if you do have anterior placenta, it won't raise the (already small) risk of miscarriage attached to this test."

What about the labour and birth? Will my anterior placenta affect that?

Having an anterior placenta means that it is more likely that the baby will be in the 'back-to-back' (or occipito posterior) position when you go into labour. In this position, your baby's head is down but the back of their head and spine is against your spine, rather than against your belly (as it is in the picture at the very top of this article).

"Most babies will move position during labour," says Dr Philippa, "but, if yours doesn't, it can mean that labour is more painful and lasts longer, and it's more likely that you might need an assisted birth – using forceps or ventouse to help the baby out."

There is also some evidence² that pregnant women with anterior placenta are slightly more likely to have an induction or C-section.

Will my placenta stay anterior for the whole pregnancy?

Yes, it will stay at the front, says Dr Philippa. "Again, this is not the same as a low-lying placenta, which can rise up as the pregnancy proceeds."

Will all my pregnancies be anterior placenta if the first one is?

Not necessarily: the placenta simply forms wherever the fertilised egg implants. And where that is varies from pregnancy to pregnancy, with no predictable pattern.

Pics: Getty and MadeForMums Community. Illustration: Jordan Edmonds-Moore

References

^{1. Placental location and pregnancy outcome. Zia et al. J Turk Ger Gynecol Assoc. 2013; 14(4): 190–193.
2.Anterior placental location influences onset and progress of labour and postpartum outcome. Torricelli et al. Placenta Volume 36, Issue 4, April 2015, Pages 463-466}

Read more:

• What is the placenta?
• What does it mean when my baby's head is engaged?
• What is nub theory: can it predicit if you're having a boy or a girl?