Reaching week 16 of pregnancy means you are settling comfortably into your second trimester. For many parents this is a welcome stretch of the journey, as the queasiness and fatigue of the early weeks often begin to ease and a small, recognisable bump starts to appear. At 16 weeks pregnant, your baby is growing quickly and developing in ways that are both remarkable and reassuring.
This week sits in a relatively quiet period between the routine early scans and the mid-pregnancy anomaly scan, so it is a good moment to understand what is happening inside, what your body is telling you, and which appointments are on the horizon. If you have just arrived here from week 15, you will notice how much changes in just seven days.
Your baby at week 16
By 16 weeks, your baby measures roughly 11 to 12 centimetres from head to bottom and weighs approximately 100 grams, around the size of an avocado. These figures are general guides rather than exact measurements, and healthy babies vary in size at every stage.
Development this week is focused on refinement. Your baby's facial muscles are maturing, allowing tiny expressions such as squinting and frowning, though these are simply reflexes rather than emotions. The skeleton is gradually hardening from soft cartilage into bone, and the limbs are becoming better proportioned, with the legs now longer than the arms.
The nervous system continues to connect with the muscles, so your baby is moving more purposefully, stretching and flexing within the roomy space of the womb. The eyes and ears are moving closer to their final positions, and the delicate bones of the inner ear are forming, laying the groundwork for hearing in the weeks ahead. The skin remains thin and translucent, with a fine network of blood vessels visible beneath.
Your body at week 16
Many parents describe the second trimester as the most comfortable phase, and around 16 weeks pregnant you may notice your energy returning as early pregnancy symptoms settle. Every pregnancy is different, however, and it is completely normal to still experience some familiar sensations.
- A visible bump. As your uterus rises out of the pelvis, your lower abdomen may begin to round out, though the timing varies widely from person to person.
- Round ligament discomfort. Sharp or dull twinges along the sides of your bump are common as the ligaments supporting your growing uterus stretch.
- Increased appetite. With nausea often fading, many find their appetite returning, and gentle, balanced meals can help you feel your best.
- Nasal congestion and mild bleeding gums. Increased blood flow and hormonal changes can affect your nose and gums, which is typically nothing to worry about.
- Early flutters, for some. A few parents, particularly in a second or later pregnancy, begin to sense the first faint movements known as quickening, though most will not feel these until closer to 18 to 20 weeks.
These experiences are usually a normal part of pregnancy. If any symptom feels severe, sudden or worrying, it is always sensible to seek advice rather than wait.
What to keep in mind this week
Week 16 is a practical time to look after your wellbeing and plan gently ahead. Staying hydrated, moving regularly and prioritising rest all support you through the second trimester. According to NHS guidance, continuing your antenatal vitamins, including vitamin D, and eating a varied diet remain important throughout pregnancy.
This is also the window in which the whooping cough (pertussis) vaccine is offered on the NHS, typically from around 16 weeks up to 32 weeks, to help protect your baby in their first weeks of life. Your midwife or GP can talk you through the timing and answer any questions. It can be helpful to map out your coming appointments, and our pregnancy journey planner lets you see a personalised timeline of scans and milestones tailored to your dates.
Scans, tests and appointments
At 16 weeks pregnant, the next routine NHS milestone is the mid-pregnancy anomaly scan, usually carried out between 18 and 21 weeks, so there is no standard NHS scan scheduled for this exact week. Some parents, however, value additional reassurance during the gap between the dating scan and the anomaly scan.
An Early Fetal Scan at 16 weeks can provide a detailed look at your baby's growth and wellbeing during this interval, offering both clinical insight and peace of mind. Where there is a specific indication, such as a family history of congenital heart conditions or findings that warrant closer review, early fetal echocardiography allows specialist assessment of the developing heart earlier than a standard scan would typically permit.
Whether any of these are appropriate for you depends on your individual circumstances, and your midwife or a fetal medicine specialist can help you decide. Later in pregnancy you can expect further routine NHS checks, including screening for gestational diabetes with a glucose tolerance test where indicated, usually between 24 and 28 weeks.
Looking ahead to week 17
As you move towards week 17, your baby will keep growing steadily and your bump is likely to become a little more noticeable. Week 16 is a lovely moment to pause, enjoy the renewed energy the second trimester often brings, and feel confident about the milestones ahead. At London Pregnancy Clinic, our fetal medicine team is here to support you with expert scanning and reassurance whenever you need it.
This article is for general information only and is not a substitute for professional medical advice. Always speak to your midwife, GP or obstetrician about your own pregnancy.
If you have concerns about your pregnancy or baby's wellbeing, contact your midwife, GP, or maternity unit promptly.
