For whatever reason, baby pregnancy trackers never seem to bother explaining how they come up with the objects used for comparisons. Babysizer feels that it's important that it be explained to you, in order for you to better visualize the size of your baby.
All comparisons on Babysizer are based on average fetal crown (top of the head) to rump (bottom of bum) length. Other pregnancy sites typically measure babies from crown to heel (head to toe) instead of crown to rump beginning in the 20th week of pregnancy. This makes things ultra confusing as one week you picture your cute little one all curled up in fetal position, but the next week you have to picture your baby standing up straight as a stick. That's a little awkward to imagine, isn't it? Not to mention if you just look at the measurements change from week 19 to 20, it's as if your baby had a ridiculous growth spurt. Babysizer specifically uses crown to rump as it better represents the size of your baby inside the womb for the entire pregnancy, making it much easier to visualize the size of your baby.
Objects were selected and assigned to a week using the longest side of the object. Short of every week being represented by a set of 38 Russian nesting doll, or babies in this case, there just aren't enough objects that are bigger in every dimension, week after week. As that's the case, you may find that one week an object is wider or flatter than the next. This is where you'll have to use a little imagination to fill in the gaps. Some minor liberties were taken in assigning objects to weeks to ensure that each week could be represented by a relatable object. Having said that, Babysizer has taken as much care as possible to select objects that are the same length as the average baby size each of the pregnancy week.
Every pregnancy is different and babies grow at different rates. While Babysizer strives to be as factually accurate as possible, Babysizer should be used for entertainment purposes only. None of the information here should be considered as medical advice. If you have any concerns about your pregnancy, you should contact a medical professional.