Week 17
Your baby now measures about 11.6 cm (4.5 in) from crown to rump and weighs around 100 g (3.5 oz), roughly the size of a pear. Every baby grows at its own pace, so these are averages only. The first fat is being laid down under the skin, the umbilical cord is growing thicker and stronger, and tiny ridges on the fingertips are settling into fingerprints. The top of your uterus now sits about halfway between your pubic bone and your belly button, and your posture is starting to shift to balance it. This week looks at your back, your iron, your pelvic floor and, for some, the first flutters of movement.
Day 113 · 16 weeks 0 days
Your baby's fingerprints are now their own
The swirls and ridges on your baby's fingertips have been forming for weeks, and by now the pattern is set. It will stay the same for life. Even identical twins, who share the same genes, end up with different prints, because the ridges are shaped by tiny differences in position, pressure and blood flow in the womb.
Other quiet changes are under way. A thin layer of fat is starting to form under the skin. For now your baby looks lean and the skin is thin enough that blood vessels show through. Over the coming months, fat will fill out the body and help with keeping warm after birth.
The umbilical cord is getting thicker and stronger too. It carries oxygen and nutrients from the placenta to your baby and takes waste back the other way. A jelly-like coating inside the cord helps protect its blood vessels from kinks and pressure, even as your baby twists and turns. Sweat glands are forming as well, along with the beginnings of the tiny muscles that will one day give goosebumps.
Try this: Press your own fingertip into a little flour or ink and look at the pattern. Your baby has one just as unique, a fraction of the size.
Day 114 · 16 weeks 1 day
Look after your back as your shape changes
Back pain affects at least half of all pregnant people, and it often begins around now. Your growing bump pulls your centre of gravity forward, so you may start leaning back to balance, which strains your lower back. At the same time, the hormone relaxin loosens the ligaments around your pelvis and spine.
Good posture takes some of the load off. Stand tall, with your shoulders relaxed and your tailbone gently tucked under rather than sticking out. When you sit, choose a chair with back support, keep your feet flat, and tuck a small cushion behind your lower back.
When you pick something up, bend your knees and keep your back straight, holding the object close to your body. Avoid twisting while lifting, and ask for help with heavy loads. Flat or low-heeled shoes with good support make a real difference. Regular gentle activity, such as walking, swimming or prenatal yoga, keeps the muscles that support your back strong.
At night, a pillow between your knees can ease strain on your lower back and hips. A warm (not hot) bath or heat pack can also help.
Call your care provider if back pain is severe, comes in regular waves, or comes with fever, burning when you pee, bleeding, or numbness or weakness in your legs.
Try this: Stand sideways to a mirror, notice your posture, then gently tuck your tailbone and lift through the top of your head.
Day 115 · 16 weeks 2 days
The first flutters may come soon
One of the most memorable moments of pregnancy is feeling your baby move for the first time. This is called quickening. In a first pregnancy, most people notice it between about 18 and 22 weeks. If you have been pregnant before, you may recognize it earlier, sometimes from around 16 weeks.
Early movements are gentle and easy to miss. People describe them as fluttering, bubbles popping, a goldfish swimming, a light tap, or something like hunger rumbles. They are often clearest when you are still, such as lying down in the evening.
Several things affect when you feel them. If your placenta is attached to the front wall of your uterus, it can cushion the kicks so you notice them later. Body shape plays a part too. Your baby has been moving for weeks, so not feeling anything yet is normal at this point.
At first the movements will be occasional and irregular. You will not feel them every day, and that is expected for now. Later in pregnancy, you will learn about your baby's own pattern of movement and why it matters. If you reach about 22 or 24 weeks and still have not felt anything, mention it to your care provider so they can check.
Try this: Spend ten quiet minutes lying on your side this evening with your hand on your belly, and simply notice what you feel.
Day 116 · 16 weeks 3 days
Build your plate around iron
As you read in week 16, your iron needs are much higher now. Food is your first line of defence, and a few tweaks can make a real difference. Iron comes in two forms. Heme iron, found in red meat, poultry and fish, is absorbed easily. Non-heme iron, found in beans, lentils, chickpeas, tofu, fortified cereals, dark leafy greens, nuts, seeds and dried fruit, is absorbed less well. You can boost absorption by pairing plant sources with vitamin C: beans with peppers, cereal with an orange, lentils with tomato. Some things get in the way. Tea and coffee contain compounds that block iron absorption, so try to drink them between meals rather than with them. Calcium can interfere too, which is why many people take an iron supplement and a calcium-rich food at different times of day.
If you eat little or no meat, you can still get enough iron. It just takes more planning. Your care provider may keep a closer eye on your blood count, and a dietitian can help you build a plan.
A note on liver: it is rich in iron, but it is also very high in vitamin A, which can harm a developing baby in large amounts. Most guidance advises avoiding liver and liver products during pregnancy.
Try this: Choose one meal today and add an iron source plus something rich in vitamin C to it.
Day 117 · 16 weeks 4 days
Lying flat on your back may start to make you woozy
As your uterus grows heavier, lying flat on your back can bring on a particular kind of light-headedness. The uterus can press on the large vein that carries blood from your legs back to your heart. Less blood returns, so your blood pressure drops. You might feel dizzy, sick, sweaty or short of breath. It usually shows up from around the middle of pregnancy. The fix is simple: roll onto your side, and the feeling usually passes within a minute or two. On an exam table, at the dentist or during floor exercises, ask to be propped up or have a pillow tucked under one hip.
The dizziness you read about in week 10, when you stand up quickly or go too long without eating, can still happen too, and the same habits help. In week 27 you will read why going to sleep on your side matters in the third trimester. For now, waking up on your back is nothing to worry about. Just roll over.
Call your care provider if you actually faint, feel dizzy often, or notice a racing or irregular heartbeat. Get help right away if dizziness comes with chest pain, severe headache, trouble breathing, vaginal bleeding or severe belly pain.
Try this: Next time you lie down to rest, tuck a pillow under one side of your back and notice whether it feels better.
Day 118 · 16 weeks 5 days
A few minutes a day for your pelvic floor
Your pelvic floor is a hammock of muscles stretching from your pubic bone to your tailbone. It holds up your bladder, bowel and uterus, and helps control when you pee or pass gas. Pregnancy puts it under steady pressure, and birth stretches it further. Leaking a little urine when you cough, sneeze or laugh is very common.
Pelvic floor exercises, sometimes called Kegels, strengthen these muscles. Done regularly, they can reduce leaking during and after pregnancy and help recovery after birth.
Here is how. Sit, stand or lie comfortably. Squeeze and lift the muscles as if you were trying to stop yourself passing gas and stop the flow of urine at the same time. Keep breathing, and try not to squeeze your buttocks, thighs or tummy. Hold for a few seconds, then fully relax for the same length of time. Work up to holding for about 10 seconds, repeated 10 times. Then do 10 quick squeezes and releases. Aim for this about three times a day. Do not practise by stopping your pee mid-flow regularly, since that can upset normal bladder emptying. It can take a few months to notice a difference, so be patient.
If you find the exercises hard to feel, or leaking is bothering you, ask about a pelvic health physiotherapist.
Try this: Link your pelvic floor exercises to something you do three times a day, like brushing your teeth or waiting for the kettle.
Day 119 · 16 weeks 6 days
Vivid dreams are part of the ride
Many people notice their dreams change in pregnancy. They may be longer, stranger and much easier to remember. Some are lovely. Others are unsettling, with dreams of forgetting the baby somewhere, giving birth to an animal, or something going wrong.
There are a few likely reasons. Hormones affect sleep, and you probably wake more often, to pee or shift position, which means you are more likely to wake during a dream and remember it. Your mind is also processing a huge life change. Dreams often borrow from worries and hopes you are carrying during the day.
Disturbing dreams do not predict the future and do not mean anything is wrong with your baby. They are more like your brain rehearsing. Talking about them often takes away their power, and many people are relieved to hear how common they are.
If dreams or worries are keeping you from sleeping, or anxiety follows you through the day, tell your care provider. Anxiety in pregnancy is common, and it is treatable.
For your partner: Ask about dreams over breakfast with curiosity, not worry. Listening without trying to fix anything is often exactly what is needed.