Pregnancy week 16

Your baby’s development

At 16 weeks your baby is about as big as an avocado. The headline this week is muscle and movement: your baby can now move the arms and legs in a more coordinated way, and the back muscles are getting stronger. The eyes drift closer together and slowly move beneath the closed lids. The ears settle into their final position and the inner ear structures are nearing the point where they can pick up sound. The head is still large compared with the body, but as the neck lengthens it can be held more upright. The nervous system is learning to steer the muscles more precisely, so movements become smoother. For some babies the sex can be seen on ultrasound around now, though this depends on image quality and the baby's position. Your baby also swallows amniotic fluid, which gets the digestive system working. Measurements are averages, and every baby progresses in its own way. Development moves at its own pace in every pregnancy; your doctor interprets ultrasound measurements, and small differences are usually ordinary.

Changes in the mother

In these weeks the uterus grows upwards and the shape of your belly becomes more obvious. If you have given birth before, you may already feel the first movements; in a first pregnancy this usually starts a little later, around weeks 18–22. At first it can feel like gas bubbles. As the ligaments that support the uterus stretch, you may notice brief pulling pains low in the belly or groin, especially when you move suddenly or sneeze. Getting up slowly and changing position gently helps most people. Your skin may look glowing, and sometimes darker in places. Night-time leg cramps can begin. If sleep is broken, try lying on your side with a pillow between your knees. If any pain or sensation worries you, speak to your doctor without waiting.

To do this week

• Review any screening test results together with your doctor.
• Try a support pillow for sleeping on your side.
• Do gentle stretches for back and groin discomfort.
• When you first feel movements, jot down the date and time.

Tip for the partner

Asking before touching the belly lets her know she is in control of her own body.

Nutrition tip

Pairing iron-rich foods with a source of vitamin C supports absorption.