Tag: pregnant with a big baby

Induction for a big baby – and what does a hamster have to do with birth?

If you follow Dr Sara Wickham, you may already know this one. The 2016 Cochrane review on suspected big babies (macrosomia) found that the difference in birth weight between babies who were induced early and babies whose labour started on its own was just 178g. That’s about the weight of a hamster 🐹 or a medium-sized pear 🍐 (see Sara Wickham’s book In Your Own Time for more!). That should make your ‘big’ baby seem a little less big and scary.

That said, it’s your body, your baby and your choice! If you feel an induction or caesarean birth is the right choice for you, then that’s what you should choose. A good doula or perinatal educator will support you in making the right decision for you and your baby, and support your choice. But if you’re reading this, chances are you feel that an induction (or caesarean) for a big baby isn’t what you want.

How can you decide whether to have an induction for a big baby?

The aim of inducing labour for a big baby is to reduce the chance of the baby ‘getting stuck’ (shoulder dystocia). In most cases, shoulder dystocia doesn’t cause any long-term problems. Here is a printable summary of the Cochrane Pregnancy and Childbirth findings to help you make the right choice for you and your baby:

Reasons you might decline an induction for a big baby

If your baby’s size is the only reason for the recommendation, you may wish to decline the induction.

The main reason induction is recommended is the assumption that big babies are at higher risk of shoulder dystocia. In reality, 7–15% of big babies have some difficulty with the birth of their shoulders, and most of these situations are handled by midwives or obstetricians without any lasting harm to the baby. Permanent nerve injury from shoulder dystocia happens in about 1 in 555 babies weighing between 8lb 13oz and 9lb 15oz, and about 1 in 175 babies weighing 9lb 15oz or more.

Interestingly, people with high blood sugar levels during pregnancy have a higher risk of shoulder dystocia even when their baby isn’t considered big. This is because the baby’s weight can be distributed differently: problems are more likely when the baby’s head is relatively small compared with their shoulders and tummy (Kamana et al., 2015).

But can we really tell how big your baby is?

How accurate are growth scans or feeling the bump (palpation)? In short, both are similarly unreliable at predicting a baby’s size.

For scan accuracy, see table 3 in this article (copied below). It shows how accurate ultrasound weight estimates were for scans done within three days before birth, preterm (before 37 weeks) and at term (37+ weeks).

Proportion of estimates within	±10%	±15%	±20%
Gestational age at scan:
<37 weeks	69.6%	85.6%	91.9%
≥37 weeks	72.8%	89.6%	95.9%

To read more about induction for big babies, I recommend:

• Evidence Based Birth
• Sarah Ockwell-Smith
• Dr Rachel Reed
• Dr Sara Wickham
• My post on using hypnobirthing during an induction