She’s about the size of a corn kernel now. Her heart’s begun to beat and can be picked up during an ultrasound scan. Her neural tube will begin to close – one end will become her brain, while the other will form her spinal cord. Dark spots will appear where your little one’s nostrils and eyes will develop, and the lens, cornea and retina begin to form. About a week later, skin begins to fold over her eyes, creating eyelids. These will be fused shut while her peepers continue to develop throughout the coming months.
It’s not unusual to feel puffy and bloated during the first few weeks of pregnancy and well before you begin to show. This is because the hormone progesterone can cause excessive wind during the first trimester, as it works to relax the muscles in your tummy to allow room for your baby to grow. Pregnancy symptoms, such as nausea, vomiting, mood swings and fatigue, may be much more noticeable now too, thanks to your increasing hormone levels.
It’s first scan time! Your dating scan confirms your baby’s expected delivery date, which will be based on measurements taken by a sonographer. While the initial glimpse of your baby will look like a blurry black and white mass, you should be able to see her heartbeat, her head, limbs, hands, feet and some organs. Your baby’s head will seem huge and, in fact, measures half the size of her body. Her reflexes are developing, and she will now weigh around 14g – that’s more than half an ounce.
The risk of miscarriage reduces dramatically this week, so now’s a good time to share your exciting news if you haven’t done so already. For most mums-to-be, nausea and fatigue will begin to wane at last, too. At the time of conception, your uterus was the size of a plum, but by this week, it’ll expand above your pubic bone where you may be able to feel it. At full term, your uterus will have expanded to 1,000 times its initial capacity, and 20 times its original weight.
She’s now the size of a carrot and a little larger than the placenta. Although you’re already nearly halfway through your pregnancy, your baby’s still only a fraction of her birth weight and will look very thin if you see her on a scan. This is all about to change, though. From now on, she’ll begin to gain about 50-60g (about 2oz) per week, as she lays down muscle, ligament and fat in preparation for life in the outside world. And the sex of your baby should now be visible on an ultrasound scan, although you won’t have your next scan for another couple of weeks.
Your bump’s probably sticking out noticeably by now. Your uterus is about the size of a large cantaloupe melon, and has expanded to sit just below your belly button. In the coming weeks, your belly button is likely to pop out a bit, but it’ll return to its usual shape within a few weeks of your baby’s birth. You’ve probably gained about 4kg (8.8lbs), or even a little more, which is considered healthy to sustain your little one’s growth.
She’s now around 28cm (11in). Her face is almost complete but her eyes are still close together at the front of her head. Her ears are in their final position. Her hair’s growing, too, but will appear white until pigment develops. Your baby’s brain waves can be detected and she can respond to your physical movements and loud noises. Her brain’s mature at 22 to 24 weeks, but the rest of her central nervous system won’t reach maturity until 36 weeks.
You may have felt the first fluttering of your baby’s movements at around 16 weeks, and now you’ll feel harder kicks and even rolls and twists. Your partner should be able to feel your little one’s acrobatics, too, and you may see your tummy move as she wiggles about. Your hair may be thicker and healthier-looking, and that isn’t limited to your head. It can sprout in unusual places, including your face, back and even your neck.
Although your baby won’t take her first breath until she’s born and the cord’s cut, she’ll practise using her lungs by breathing amniotic fluid (you may notice she gets hiccups as she does this). She’s building up a layer of white fat under her skin and looks pinker. Her ears are almost fully developed – inside and out – and she’ll respond to familiar sounds, like your voice. She now weighs an average of 1.15kg (2.5lbs), and measures about 39cm (15.5in).
You’ll be gaining about 500g (1lb) a week as your baby grows. Throughout your pregnancy, your blood volume increases by 40 to 50 per cent, to accommodate both your needs. This may make you feel rather warm and sometimes a little faint, as your blood pressure and/or blood sugar drops. Your heartbeat will increase by about 10 to 15 beats per minute to keep your blood pumping, and your heart will have to work between 30 and 50 per cent harder.
She’ll be about 51cm (20in) and 3.4kg (7.5lbs). She’s got eyelashes, eyebrows, fingernails and maybe some hair. Although her sight will develop further after birth, she’ll be able to see you when she’s born. Being squeezed down the birth canal will empty her lungs of fluid so she can begin breathing oxygen.
As your labour approaches, you may have mixed feelings. Try not to worry – your baby will come when she’s ready and you’ll adapt to motherhood just like you have every other challenge. Relaxation and positive thinking can encourage a positive labour, so give yourself a pep talk – you made this baby, so you’re certainly capable of delivering and caring for her.
- Until eight weeks, your baby will have a tail. This recedes and forms what’s commonly known as the tailbone.
- The umbilical cord, which transfers oxygen and food to your baby via the placenta, is about 50cm (20 in) long.
- Around 21 weeks, your baby will grow a layer of downy hair called lanugo (Latin for wool) to help regulate her temperature.
- All babies have blue eyes in the womb and they won’t achieve their final colour until a few months after birth.
- At 32 weeks, your baby can suck, so if she was born now, she might be able to breastfeed or drink from a bottle.