Comparing an unborn baby to a fruit or vegetable may seem strange to those who haven’t been on the pregnancy journey – yet there’s something compelling about making fruity comparisons to the size of your unborn baby as they develop from an egg the size of a pencil dot into something that usually weighs in between three to four kilograms at a full term birth.

The fruit salad of changing shapes and sizes as an unborn baby grows inside a woman’s belly is one of those quirky things that seems to make pregnancy that little bit more interesting for dads and mums-to-be. Just as “you’re a peach” is a compliment, while “you’re bananas” is an insult, your developing baby’s size will run the full gamut of fruit salad.

“I’m not sure why pregnancy and food are so connected,” says dietitian and dad to baby Ruby, Joel Feren. “We referred to the baby as ‘peanut’ during the pregnancy. And when we were in the supermarket, my wife held up on orange to her stomach to show me how big the baby was that week.”

Perhaps because so much of what happens during pregnancy happens inside our bellies – where we can’t see what’s really going on – means everyday objects like fruit and vegetables become the best visual metaphor to explain what is essentially inexplicable.

The truth is, every embryo and fetus is as unique as its parents, and there is no ‘one-size-fits-all’ approach to the week-by-week growth of a baby in utero. And while it’s normal to think and feel the baby in your belly is huge and wearing a giant pair of Nikes to kick you from the inside, these fruit and vegetable size references bring us back to reality to understand how small developing babies really are.

fruits of your labourYour unborn baby grows from the size of a poppy seed to a watermelon, before it arrives in your arms as a baby after 40 or so weeks of pregnancy.

What happens in the first trimester: your baby week 1 to 12

From poppy seed to apricot

Your due date is actually calculated from the first day of your last period, which means your baby isn’t even conceived until around week two. When the egg is first fertilised, the ova and sperm create what’s known as a zygote – the ball of cells which is about the size of a poppy seed. This then grows into a proper embryo, developing a beating heart and even tiny limbs which is around the size of a pomegranate seed by week six.  Nine weeks after conception – or week 11 of the pregnancy – is when your embryo officially turns into a fetus and it might be the size of a raspberry or a cherry. By the end of your first trimester of pregnancy – week 12 – your unborn embryo could be around 5cm long – around the size of an apricot or plum.

What happens in the second trimester: your baby week 13 to 27

From lemon to eggplant

Things get interesting in the second trimester – hopefully you’ve had an ultrasound to get a glimpse at what’s really going on inside your belly as your baby grows. You may start regular midwife, obstetrician or GP visits now, and you’ll get to hear your unborn baby’s heartbeat – it usually beats a lot faster than yours. The baby’s fetal heart rate varies, just like yours does, and the heart rate changes as the baby grows inside you. By week 16, your fetus could be the size of an avocado and you might start feeling the baby flutter inside you, or maybe even hiccuping. The second trimester is a time of rapid growth and development of the unborn baby, with it growing to the size of a mango by week 20 and maybe even as long as a banana by week 22. By the end of your second trimester, the fetus will be rapidly putting on weight and could be as long as 30 to 37cm, which is longer than most corn cobs and around the size of a large eggplant.

What happens in the third trimester: your baby week 28 to 40

From cauliflower to watermelon

The last trimester is considered the home stretch – your unborn baby will be laying down more fat stores and growth will start to slow down compared to the second trimester as space becomes more limited. As you usher in your final trimester, the baby could be around the size of a cauliflower – it will also have eyelashes and is able to stick out its tongue and grasp at the umbilical cord. By week 32, your unborn baby maybe as long as a butternut pumpkin, and will likely be tumbling and turning inside your belly. By week 38, the baby could be the size of a large cabbage and the movements may start to slow down. While many babies are born in week 40, plenty of them stay comfortable and remain inside until week 41 or 42. By this stage, your baby is the size of a watermelon, or potentially a jackfruit.  Baby boys tend to weigh more than girls, and the size and length of a baby at birth can vary depending on factors like genetics and even the altitude at which a baby is born. The normal birth weight in Australia ranges between 2.5kg and 3.99kg – about the size of a weekly fruit and vegetable shopping basket. Make sure you eat enough daily serves of fruit and vegetables, and remember you can supplement with a daily glass of MamaCare to get 26 nutrients essential to nourish you and your developing baby.

SOURCES: Perinatology.com, Joel Feren dietitian, Embryology