Human embryo at 4 weeks. At this stage the embryo measures about 5 millimetres. The eyes and ears are beginning to develop.

Week 4

Mum

You’ve already noticed the changes. Your breasts seem fuller. Your skirt feels tighter, even though the baby is so tiny you can barely see the bunch of cells with your naked eye. You find yourself cleaning the top bookshelf – the one you’ve been meaning to dust since the Christmas before last. Towards the end of week four, you do yet another pregnancy test and … YES!!! Medical science has finally confirmed what you’ve known for a while – you’re growing a baby inside you.

Dad

Congratulations, you’re going to be a dad! It’s all right to freak out a bit at this point, or to start making a bucket list of all the things you’d like to do before your life becomes a stream of nappies. That’s perfectly normal. Many parents fear that the baby’s arrival will put their projects and ambitions on hold. They’re not entirely wrong, but don’t worry – the baby itself will become the biggest project you’ve ever undertaken, and it will satisfy your wildest ambitions.

Your partner is not the only one who’s expecting – you’re in it together. Although you may not know what to do, chances are, neither does she. Just be there for her, and read up on what you can expect your role to look like when the baby is being born, and beyond

She’ll be advised to play it safe when it comes to alcohol. Because nobody knows what the safe limit is – the official line is no alcohol during pregnancy. You might like to support her by not drinking for the next nine months, too.

Baby

Hey, baby, you are now officially an embryo with two layers of cells – the epiblast and the hypoblast! Your heart, digestive system, backbone and spinal cord are already beginning to form. In the next six weeks, more organs will begin to develop, and some will even start to work. Meanwhile, you are about the size of a poppy seed measuring at approximately 0.2mm

Things to keep in mind 

  • While you’re unlikely to have an ultrasound just yet, the gestational sac would already be visible at this stage.
  • You may experience some implantation bleeding at this stage as the bundle of cells that are your baby burrows its way further into your uterine wall.
  • Eating well, getting in a little physical exercise, and taking some extra time to rest can go a long way to help you combat symptoms such as fatigue and mood changes.
  • If you haven’t already, begin to take prenatal vitamins and folic acid, but also ensure you are getting in your vitamin D and some healthy fats like omega-3 fatty acids.

Photos in the bumpandbaby.co.nz/week-by-week/ are by Lenart Nilsson. Lenart's series was bought to fame when his photo, considered the greatest photo of the 20th century, appeared on the cover of Life magazine in 1965. “Everyone interprets images differently, depending on their social, cultural and religious background. In the digital era, I believe it is more important than ever to go back and take a look inside ourselves. What better way of doing that than with these photos?” ~ Jane Stene, art gallery director and curator of Lenart's definitive black and white series, told the The Guardian in 2019. It is Lenart Nilsson's wish that his images are never used for political debate about pro-life.

WELCOME

Lernart Nilsson's foetus series featured in our week by week, is considered the greatest photography of the 20th Century. You may be surprised at the incredible detail seen in his photos.

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