Week 16 usually brings an antenatal appointment, and it is the one where results from the booking bloods come back. Blood pressure and a urine sample become routine from here to the end. Some women hear a heartbeat for the first time at this visit.
Your body this week
The bump is growing and weight is usually going on. Most of what happens this week happens in a clinic room rather than in your body.
At the appointment, the NHS describes blood pressure being checked and a urine sample tested for protein. Protein in urine alongside raised blood pressure is what clinicians look for when assessing pre-eclampsia, a condition of the second half of pregnancy that can be present before a woman feels anything at all.
That is the reason these short appointments matter more than they feel like they do. ACOG makes the same point: high blood pressure in pregnancy is frequently silent, and monitoring is how it is picked up.
What you may notice
Constipation is the complaint of this stretch. The NHS suggests high-fibre foods, regular exercise and plenty of water, and advises talking to a midwife or doctor before stopping any prescribed supplement that may be contributing.
Otherwise: sore gums, round ligament pains, headaches, nosebleeds, bloating, indigestion and heartburn, sore breasts, leg cramps, feeling hot, dizziness, swollen hands and feet, urine infections, vaginal infections, and skin and hair changes.
Some women feel the first movements from around week 17, so anything you feel now is early rather than late.
Your baby this week
Around week 16, the length given is about 11.6cm from head to bottom — avocado-sized, in the NHS's illustration. These are averages, and a scan measurement above or below them is a matter for a clinician, not a verdict.
The nervous system is developing enough for arms and legs to move. Hands can form fists. Facial expressions happen but are random, because there is no muscle control yet.
What care usually happens around now
In the UK, an antenatal appointment at around 16 weeks covers blood pressure, urine, and the results of booking blood tests — including screening for HIV, hepatitis B and syphilis, and a check for anaemia. If an infection has been found, treatment and care to reduce the chance of passing it on are discussed then.
Some services also do routine carbon monoxide breath testing at appointments. Schedules and content differ between countries; ask what your own service does at each visit.
This week's tip
Ask what your booking blood results actually said, and write the numbers down. "All normal" is a summary, not a record. Knowing your blood group, your rhesus status and your haemoglobin level matters later — rhesus status in particular decides whether anti-D is offered in the third trimester.
When to see a doctor
Contact a midwife or GP for bleeding, severe pain, a fever, burning when you pee, or constipation that is not shifting. A headache with vision changes, or sudden swelling of the face and hands, needs care today. Pregnancy warning signs has the list.
Seek care now: Contact your local emergency services or go to your nearest emergency department if you have heavy bleeding, severe or one-sided tummy pain, a severe headache with vision changes, sudden swelling of the face or hands, a fever, fluid leaking from the vagina, chest pain, trouble breathing, fainting, or a seizure. Femio cannot assess a pregnancy.
Frequently asked questions
Why do they test my urine every time?
Mainly for protein, which alongside blood pressure is one of the things clinicians watch for through the second half of pregnancy. It takes a minute and it is one of the most useful minutes of the appointment.
I have not felt anything move yet. Is that late?
No. Most women notice movements between 18 and 24 weeks, later in a first pregnancy. Week 17 covers what early movements feel like, and week 15 covers the week before.