At 14 weeks, a fetus measures roughly 3.5 inches (about 9 centimeters) from the top of the head to the bottom of the buttocks and weighs just over an ounce. From head to heel, the measurement stretches to almost 6 inches, though the crown-to-rump number is the standard one used in ultrasound because the legs are often curled up. The most common comparison: a 14-week fetus is about the size of a lemon.
How Size Is Measured at This Stage
Doctors use crown-rump length (CRL) during the first trimester and into the early second trimester because it’s the most reliable way to gauge growth on ultrasound. The fetus is curled in a C-shape, so measuring from head to heel isn’t practical until later in pregnancy. By 14 weeks, CRL typically falls around 8 to 9 centimeters, though individual variation of a few millimeters in either direction is normal.
Weight is harder to pin down at this stage because the fetus is still very small and mostly fluid. Estimates put it between 1 and 1.5 ounces (roughly 30 to 45 grams). That’s light enough to rest on two fingers, yet it represents a dramatic jump from just a few weeks earlier. Between weeks 12 and 14, both length and weight increase rapidly as the fetus transitions from the embryonic growth pattern into a phase of steady size gains.
What the Fetus Looks Like at 14 Weeks
By now the face has taken on a distinctly human profile. The eyes, which formed on the sides of the head, have migrated closer together and can move slowly. The ears are nearly in their final position on either side of the head. Facial muscles are developed enough that the fetus can squint, frown, and grimace, though these movements are reflexive rather than intentional.
The body is starting to look more proportional. Earlier in development, the head made up nearly half of the total length. At 14 weeks, the body is catching up, and the limbs have lengthened noticeably. Fingers and toes are fully separated, and fingerprints are already beginning to form (they’ll be permanently set before 20 weeks). Fine, downy hair called lanugo is starting to appear across the skin, helping regulate temperature.
What’s Happening Inside the Body
Fourteen weeks marks a turning point for organ function. The kidneys began producing urine around week 13, as new filtering units multiplied rapidly, and by 14 weeks they are actively processing amniotic fluid. The fetus swallows small amounts of this fluid, a process documented as early as 12 to 14 weeks of gestation, then passes it through the developing digestive and urinary systems. This cycle of swallowing and urinating plays an important role in maintaining the right volume of amniotic fluid surrounding the baby.
The liver is beginning to produce bile, and the spleen is starting to contribute to red blood cell production. The thyroid gland is functional and producing hormones. None of these organs are fully mature, but they are actively practicing the tasks they’ll need to perform at birth.
Movement at 14 Weeks
The fetus is moving constantly by this point, stretching, kicking, and flexing its arms and legs. It can bring its hands to its face and may even start sucking motions (true sucking reflexes are typically observed around 15 weeks). These movements are driven by a rapidly developing nervous system, but they’re still too small for most pregnant people to feel. First-time parents usually don’t notice fetal movement until 18 to 22 weeks, though those who have been pregnant before sometimes pick it up a few weeks earlier.
The Start of the Second Trimester
Week 14 is officially part of the second trimester. For many people, this transition brings welcome relief from the nausea, fatigue, and food aversions of the first trimester. Energy levels often pick up noticeably over the next few weeks.
Physically, the uterus is growing out of the pelvis. At about 13 to 14 weeks, the top of the uterus typically sits just above the pubic bone, which means a small, firm bump may be visible or palpable for the first time. This is the stage where pregnancy starts to “show” for many people, though body type, muscle tone, and whether it’s a first pregnancy all influence when that happens.
Can You Tell the Sex at 14 Weeks?
External genitalia are forming by 14 weeks, and in some cases an experienced sonographer can identify the sex on ultrasound. A study published in the Australasian Journal of Ultrasound in Medicine found 100% accuracy for sex predictions made after 14 weeks, though the sample size at exactly 14 weeks was small. In practice, many clinicians prefer to wait until the anatomy scan around 18 to 20 weeks for a confident call because fetal position and image quality can make earlier predictions tricky. If you had noninvasive prenatal testing (NIPT) through a blood draw around weeks 10 to 12, those results can reveal chromosomal sex with high accuracy well before any ultrasound.
How Growth Compares Week to Week
To put 14 weeks in context, here’s how fetal size changes during this stretch of pregnancy:
- Week 12: About 2.5 inches CRL, roughly the size of a lime
- Week 14: About 3.5 inches CRL, the size of a lemon
- Week 16: About 4.5 inches CRL, closer to an avocado
Growth accelerates through the second trimester. Over the next six weeks, the fetus will more than double its current weight and add several inches. By 20 weeks, it will be roughly 10 inches from head to heel and weigh around 10 ounces.