Find out about your baby’s size and position

Our midwife answers your questions and explains what it means when your baby is back to back or whether your bump is the right size

find-out-about-your-babys-size-and-position_1251

1) What is a back-to-back position?

Q: At my 34-week check my midwife told me that my baby is in a back-to-back position and this might be a problem in labour. What exactly does she mean?

Advertisement

A: By the end of pregnancy most babies will be in an occiput anterior position (OA). So your baby is facing your back, with his spine curving outwards with your bump. It’s the best position for him to fit through your pelvis . But his back may be curved in line with yours, in an occiput posterior position (OP).It may mean a longer labour but doesn’t mean you can’t have a vaginal delivery, although there is a slightly increased chance of ventouse or forceps at the end.

Encourage him to move by staying upright and leaning over in labour. Before b-day try swimming on your front and keeping your knees lower than your pelvis to help him turn into the right place, too.

2) Is my baby facing the wrong way?

Q. I’m 33 weeks pregnant and my midwife says my baby is lying ‘back to back’. Does this mean I’ll need a caesarean?

A. When your baby’s lying back to back it means he’s facing your bump. This is called the occiput posterior or OP position (the occiput is the back of your baby’s head). Nearly all (95 per cent) of OP babies will move to face the other way before labour begins, but if your baby doesn’t do this you can still have a vaginal birth. It may last longer however, and you have an increased chance of an instrumental delivery. You’re also more likely to suffer backache during the birth.

There are some tips that are thought to encourage babies into the ‘optimum’ position, including trying to keep you knees lower than your pelvis (this means not sitting with your legs crossed) and spending some time each day kneeling or standing leaning forward so your abdomen is relaxed. But don’t worry; most babies will negotiate the best way through the pelvis, especially if you can keep mobile for some of your labour.

3) When does my baby’s head engage?

Q. Everyone in my antenatal class keeps talking about whether or not their baby’s head is engaged yet. What exactly does this mean and how will I know?

A. As your body prepares for birth, your baby moves lower down into your pelvis. This often happens around 38 weeks and your midwife will be able to tell if your baby’s head has started to get lower when she feels your bump.

How much of your baby’s head can be felt above the brim of your pelvis is expressed as a measurement of fifths. If all of the head can be felt, it’s described as 5/5 palpable. If it’s engaged it would be 2/5. This will be written in your antenatal notes.

Some women say they can feel when their baby’s head has engaged as their bump feels lower and they have less pressure under their ribs, but plenty of women can’t feel any difference. 

Not all babies engage into the pelvis at the end of pregnancy. Some babies don’t move down until the contractions during labour push them into position.

4) Just a little one?

Q. I’m 32 weeks pregnant and my midwife thinks that my baby isn’t as big as he should be by this stage. Should I be worried? I’m seeing the doctor in a week.

A. As part of an antenatal check your midwife will measure the height of your uterus and plot it on a growth chart alongside how many weeks pregnant you are, in order to get an indication of whether your baby’s growing at the right rate. Babies are always going to vary in size and there are various factors to take into consideration including your stature, his position and the amount of fluid around him. If your baby’s growth is being affected (a condition known as intrauterine growth restriction), there’s often nothing to explain why this should be happening. However, it can sometimes be linked with a placental problem that is often the result of high blood pressure. The important thing is that any concern is swiftly acted upon, and that you are closely monitored. If the doctor’s very concerned he might advise that your baby is delivered early. However, don’t be surprised if, in a couple of weeks’ time, your baby has a growth spurt.

5) Is my bump too small?

Q. I’ve just started antenatal classes and my bump looks so much smaller than everyone else’s. Should I be worried?

A. Worrying that a bump is too small, too big, too high or too low is one of the most common concerns for mums-to-be. But it’s important to know that the size and shape of your bump will vary hugely depending on your height, weight, shape, ethnicity and how many babies you’ve had before.

When your midwife sees you at an antenatal appointment she’ll be monitoring the size of your bump and comparing it to the measurement from your previous appointment. Should there be any concerns about the growth of your baby, she’ll refer you to an obstetrician and may arrange an additional scan.

Advertisement

If you’re still genuinely worried, tell your midwife so she can reassure you further.

Comments

Please read our Chat guidelines.