16 weeks pregnant
Your baby can make faces now.
In short
At 16 weeks your baby is about the size of an avocado, around 18.6 cm long and 144 g. Your baby can make faces now.
- Second trimester, week 16 of about 40.
- The whooping cough vaccine is recommended between 16 and 36 weeks in every pregnancy. It's free at GP practices that take part in the Maternity and Infant Care Scheme.
Turn your baby round in 3D every week in the free Lullagram pregnancy section
Your baby can move the muscles in their face, which looks like expressions, though they aren't in control of them yet. Amniotic fluid moves in and out of the lungs, helping them get ready for breathing air.
How big is my baby at 16 weeks?
At 16 weeks your baby is about the size of an avocado, around 18.6 cm long and 144 g. Before about 14 weeks babies are measured from crown to rump; after that the figure is head to heel. These are typical figures from fetal growth charts. Your own baby may be bigger or smaller, and your scans are what count.
What is my baby doing at 16 weeks?
- Your baby can move the muscles in their face, which looks like expressions, though they aren't in control of them yet.
- Amniotic fluid moves in and out of the lungs, helping them get ready for breathing air.
- The arm and leg muscles can flex as the nervous system develops.
- Your baby's hands can find each other, make fists and hold on.
What changes for me at 16 weeks pregnant?
- Most people first notice their baby moving somewhere between 16 and 24 weeks, often as a gentle fluttering.
- In a first pregnancy it's common to notice movements later.
- Constipation is common, so plenty of fibre and water can help.
- From around now, lying on your side is usually more comfortable than lying on your back.
What is a good tip for this week?
Add fibre with porridge, wholegrain bread, fruit and vegetables and drink plenty of water to keep things moving.
What can a partner do this week?
Help arrange the whooping cough vaccine appointment with the GP.
What should I know in Ireland at 16 weeks?
- The whooping cough vaccine is recommended between 16 and 36 weeks in every pregnancy. It's free at GP practices that take part in the Maternity and Infant Care Scheme.
When to get help: Contact your midwife, GP or maternity unit straight away if you have any bleeding from your vagina. HSE: when to get help.
Want these updates on your phone? The Lullagram app has a free pregnancy section with this week-by-week guide, Irish dates worked out from your due date, a contraction timer and more. When your baby arrives, the baby tracker is ready in the same app.
Guides for your pregnancy: pregnancy care in Ireland · maternity leave and benefit · hospital bag checklist · popular baby names · free IVF in Ireland · due date calculator
Sources and guidance
This page is written to be consistent with the official guidance below. It is general information for parents in Ireland, not medical advice. Links checked 23 September 2026.
A great app that has made them late night feeds and nappy changes easier. The fact my account links with my partner means we both know how baby is doing and takes away the guess work at night of what time baby is due or has been feed. Looking forward to using the other elements of the app as our little man grows.