At 14 weeks pregnant, your baby measures about 3.5 inches (87 millimeters) from the top of the head to the bottom of the tailbone and weighs roughly 1.5 ounces (45 grams). That’s about the size of a lemon. Week 14 also marks the very start of the second trimester, a period of rapid growth where your baby will go from that small citrus fruit to something much more recognizably human in a matter of weeks.
How Baby Size Is Measured at 14 Weeks
The measurement your doctor uses at this stage is called crown-rump length, which runs from the top of the skull to the base of the spine. Legs aren’t included because they’re still curled tightly against the body, making a head-to-toe measurement unreliable. Crown-rump length is the standard for dating pregnancies up through about 14 weeks, after which other measurements like head circumference, abdominal circumference, and thigh bone length become more useful for tracking growth.
If your ultrasound measurements come back slightly above or below 3.5 inches, that’s normal. A World Health Organization study tracking fetal growth across multiple countries found wide variation in healthy pregnancies. At 14 weeks, measurements between the 5th and 95th percentiles all fall within the expected range. Genetics, parental height, and even the exact day within the week can shift the numbers. A measurement that’s a few millimeters off the average rarely signals a problem on its own.
What 1.5 Ounces Looks Like
One and a half ounces is lighter than a standard AA battery. It’s roughly the weight of a handful of grapes. The lemon comparison works well for shape too: your baby’s head still makes up a large proportion of the body, giving it an oblong profile on ultrasound. Over the coming weeks, the body will lengthen and the proportions will even out, but right now the head accounts for about a third of the total length.
What’s Developing Inside
Size is only part of the story. At 14 weeks, your baby’s internal systems are hitting key milestones that set the stage for the rest of pregnancy.
The kidneys are forming their early structure. At this gestational age, the kidneys are still lobulated, meaning they have a bumpy, segmented surface rather than the smooth bean shape they’ll eventually take on. They’re beginning to produce small amounts of urine, which gets released into the amniotic fluid. This process is important because it contributes to maintaining the right volume of fluid surrounding the baby.
Facial muscles are well on their way. The nerves that control facial movement appear around weeks 10 and 11, and the muscles they connect to have been developing since week 8. By 16 weeks, all the muscles needed for facial expressions will be fully formed. At 14 weeks, your baby is somewhere in the middle of that process, with early movements like squinting and grimacing already possible, though they’re reflexive rather than intentional.
The body is also starting to develop a fine layer of soft hair called lanugo, which typically appears between weeks 16 and 20. At 14 weeks, the skin is still translucent and paper-thin, with blood vessels clearly visible underneath. Lanugo will eventually cover most of the body, helping to regulate temperature and hold a protective waxy coating against the skin.
How Growth Changes From Here
Week 14 is a turning point. During the first trimester, development focused on building organ systems from scratch. Now those systems are in place, and the second trimester is when your baby puts on serious size. Growth accelerates dramatically: by week 20, your baby will be roughly 6.5 inches long and 10 ounces, more than six times the current weight. By the end of the second trimester at week 27, expect measurements closer to 14 inches and over 2 pounds.
This is also when your body starts to show the changes more visibly. At 14 weeks, the uterus is rising out of the pelvic cavity, and many women notice their lower abdomen firming or a small bump becoming visible, particularly in a second or later pregnancy. The timing varies quite a bit from person to person, though, so not showing yet at 14 weeks is completely typical.
What You Might See on Ultrasound
If you have an ultrasound around 14 weeks, you’ll likely see a recognizable baby shape for the first time. Arms and legs are distinct, fingers and toes are separated, and you may catch your baby moving, stretching, or bringing a hand to the face. The movements can look surprisingly active, even though you probably can’t feel them yet. Most women don’t notice fetal movement until somewhere between 16 and 22 weeks.
Your provider may take several measurements during this scan: head circumference, the length of the thigh bone, and abdominal circumference. These numbers get plotted on a growth chart and compared to percentile curves. A single measurement that’s slightly off the average means very little. Doctors look at trends over multiple appointments to assess whether growth is tracking normally. If your baby measured a bit small or large at one visit, the follow-up scan weeks later is what gives the full picture.