Weight gain and pregnancy continued

What if my baby is too large?

Few babies are too big to push out. Babies tend to grow to 'fit' their mum's pelvis, but if they're genuinely too big to come out vaginally, your midwife will pick up on signs during labour. Sometimes babies have a 'deflexed head' during labour. This is when their chin isn't tucked onto their chest but is looking slightly up, which increases the dimension that has to go through the pelvis.

With good, strong contractions, however, the position can change. If your baby is 'too big' - a condition called cephalopelvic disproportion (CPD) - you'll need a caesarean section.

How will I know if my bump is the right size?

At each ante-natal appointment, your midwife will feel your abdomen and measure the distance from the top of the uterus to your pubic bone. Each week of pregnancy will measure about 1cm (1/2 in) on your bump.

If she feels that your baby isn't growing as well as he should be, she may send you for a scan to measure the growth or for a consultant opinion. If your baby feels significantly larger than expected, she'll do a blood test to rule out diabetes (glucose load test). But remember, not all babies are average size, and there will always be some that are bigger and some that are smaller.

What can affect the growth of my baby?

The source of nutrition and oxygen for your baby is the placenta, so if this isn't working as efficiently as it should be, it can slow down the growth. High blood pressure or pre-eclampsia can affect the placenta, as can smoking and malnutrition.

Diabetes in the mum-to-be can also affect a baby's growth, either slowing it down or, more commonly, causing it to become large before term. But diabetic mums will have close antenatal care and regular scans monitoring their baby's growth, development and wellbeing.

Where next?

- Food and pregnancy: what should I be eating?
- Try our Superfood pregnancy diet
- What should I avoid when pregnant? Read our checklist
- Should you drink when pregnant? Read our expert's advice

- Want advice from other mums? Talk about it in Chat