Your doctor or midwife will monitor your baby’s growth during your pregnancy.
If you have a small baby during pregnancy, this means your baby weighs less than 9 out of 10 babies at the same stage of pregnancy.
You may be referred for tests if they are worried that your baby is:
- smaller than they should be for that stage of pregnancy
- growing slowly
These tests may:
- measure the size of the baby and the blood flow through your placenta and umbilical cord - this is called a Doppler scan
- measure the fluid around your baby
- trace your baby’s heart in your third trimester
Causes of a small baby during pregnancy
Your baby may be small for reasons that will not affect their health.
For example, you or your partner:
- were small babies
- are from certain ethnic backgrounds, such as Asian
Your chances of having a small baby increases if you:
- had diabetes before pregnancy that was poorly controlled - ask your GP or diabetes care team for advice
- smoke
- take drugs (especially cocaine)
- are underweight
- you had a small baby before - tell your doctor if you had a baby who was small at birth
- there is a genetic condition causing your baby to be small
Restrictions to your baby’s growth
Your baby may be small because they are not growing as well as they should. This is called being 'small for gestational age'.
There are a number of reasons why your baby may be small.
For example:
- your placenta is not working as it should - this may due to smoking, drugs, high blood pressure or pre-eclampsia
- you have an infection during your pregnancy
- your baby has a genetic or health problem
If your baby is small, they will need to be monitored more. This is because there is an increased risk of stillbirth.
Be aware of your baby's movements.
Contact your midwife or obstetrician immediately if there are any changes. Your midwife will give you a kick chart and advice.
Giving birth to a small baby
You may need to give birth in a maternity hospital which has a special care baby unit (SCBU) or a neonatal intensive care unit (NICU).
Your baby's delivery date will depend on their growth and scan measurements.
If your baby is growing and the Doppler scans are normal, you can plan for delivery after 37 weeks of pregnancy. If there are no other complications, you may be able to have a vaginal birth.
If your baby's growth slows down or the Doppler scans are not normal, you may need to give birth early. This may happen if your healthcare team feel that carrying your baby to full term will put them at risk. You may be offered a course of steroid injections before 34 weeks of pregnancy. This is to help your baby’s lungs after birth.
