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3rd trimester

11 weeks pregnant

Your baby at 11 weeks

Foetus at 11 weeks pregnant

Your baby's vital organs are all in place, so she's busy growing. She'll double her weight this week from 7g to 14g, but spectacularly by week 20 she will weigh 300g. This is more than a 30-fold rise in weight.

She will also be four times as long, measuring around 4.1cm now and 16.4cm by week 20.

  • She is developing her lungs, which are slow and intricate to make.
  • There may soon be a tiny bud that depending on the sex will become the penis or the clitoris. If your baby is a boy, his testes will have started to produce testosterone.  
  • The four chambers of her heart are developing and so are the valves that control the flow of blood through the heart. Her heart will beat at between 150 to 180 beats a minute, which is twice as fast as your heart.
  • Her face is coming along nicely. Her ears are moving up the side of her head to close to where they should be.
  • She is lying in the foetal position with her chin on her chest (because her head is still so big and heavy and she hasn't quite got neck muscles) and knees curled up.
  • Her skin is still thin, so thin you can see blood vessels through it.

Your body at 11 weeks pregnant

  • Putting on weight You know it has to happen and sooner or later you will feel your clothes pinching around the waist (or the chest). The average woman will gain about 10-15 kg or between 1.5 and 2.5 stone. Weight gain in pregnancy is of the plan to lay down fat stores especially for breastfeeding and, unfortunately, those fat stores seem to be on the bottom and tops of thighs. You may not put on weight in this first trimester if you have been sick.
  • Nosebleeds The increase in blood flow is to almost everything and in the delicate mucous membranes of your nose it can mean one sneeze too far can cause a nose bleed. This is also why your gums bleed when you look at them.
  • Your bra size It may increase by a dramatic three cup sizes in the first 12 weeks but it does then slow down.
  • Feeling breathless You may start to feel short of breath because your body needs more oxygen to supply your baby and growing womb. To do this your lungs increase their tidal volume by 40% - this is the amount of air they breathe in and out in each breath. So you get more oxygen and get rid of more carbon dioxide. Progesterone is also thought to have a direct effect on the brain, which makes you breathless.
  • Feeling maternal Some women start talking to their foetuses early. Others can't believe there's anyone in their womb before it pops out. There is no link between which one of these you are and how good a mum you'll be. Promise.
Exercise during pregnancy tips
• It is fine to get slightly out of breath but don't be so out of breath you're gasping
• Wear a good bra
• Drink enough fluid
• Stop if you have contractions, vaginal bleeding, dizziness or a headache
  • Exercise during pregnancy If you thought you'd be able to put your feet up and watch TV - forget it. NICE says there is no evidence that beginning or continuing moderate exercise is harmful to your baby. The American College of Obstetricians and Gynaecologists says that exercise in pregnancy increases your energy, mood and posture, helps you sleep better and may reduce backache, constipation and swelling as well as prevent diabetes of pregnancy. You have to be careful because your pregnancy hormones make your joints more relaxed and mobile so there's more risk of injury. This and the growing baby in front of you can make you unstable.

Safe sports during pregnancy

  • Swim, cycle, walk – 30 minutes, three times a week
  • If you were a runner before pregnancy you can keep running, but if you run on grass don't turn your ankle (the ligaments may be looser)
  • Avoid downhill snow skiing (hard to balance with a baby on board)
  • Avoid all contact sports, including racket sports, where you may not mean to have contact but you can be hit by a ball
  • Do not scuba dive - it can put your baby at risk of decompression sickness, which is deeply unfair and dangerous



Pregnancy Encyclopedia book coverIllustrations taken from The Pregnancy Encyclopedia, £25, published by DK.

Disclaimer: The information in the pregnancy calendar is for general information and is not intended as a substitute for the medical advice of your own doctor or antenatal team. Not all babies develop at the same time and in the same way, so this week-by-week guide may not always match your own experience. If you have any worries, consult your antenatal team or GP.

Last updated: 4 months ago