At 17 weeks, a fetus measures about 12 cm (4.7 inches) from crown to rump and weighs roughly 100–150 grams, similar in size to a pomegranate.
You’re 17 weeks along, and the baby’s growth is taking off. Fruit comparisons keep showing up in your pregnancy app—pomegranate, onion, papaya, turnip, pear. Each source uses a different one, which can make you wonder which size is right.
The answer is that all these comparisons are rough approximations, not exact measurements. Your baby is about 12 cm from head to bottom, and the actual size depends on the fetus’s position and individual variation. This article walks through the key numbers, development milestones, and what to expect this week.
Size and Weight: The Numbers Behind the Fruit Comparisons
The most authoritative measurement comes from the NHS: from crown to rump, the baby is around 12 cm long. That’s about 4.7 inches—a length that can be pictured as roughly the height of a standard drinking glass.
Weight at this stage is approximately 100 to 150 grams, or 3.5 to 5.3 ounces. That’s less than a stick of butter. The head diameter is about 4 cm, and the feet are only 2 cm long—tiny enough to fit on your fingertip.
Why So Many Different Comparisons?
Different sources pick familiar objects to help expectant parents visualize growth. The NHS uses a pomegranate, What to Expect compares it to a large onion, and WebMD likens the full body length (head to heel) to a papaya. Because these objects vary in shape and size, the fruit comparison game isn’t exact—but they all point to a fetus that’s now big enough to be consistently felt if you start paying attention.
Why the Fruit Confusion Matters for Your Mental Picture
When you hear “size of a pomegranate” from one source and “size of a papaya” from another, it’s natural to worry something is wrong. The difference comes from whether they measure crown-rump or head-to-heel. Crown-rump (12 cm) is the most common clinical measurement; head-to-heel (about 25 cm or 10 inches) includes the legs. Both are normal.
- NHS (pomegranate): Uses crown-rump length (12 cm) for the primary size reference.
- What to Expect (large onion): Also uses crown-rump, similar to the NHS but with a different object.
- WebMD (papaya): Measures head to heel (10 inches), explaining the longer comparison.
- BabyCenter (turnip): A smaller root vegetable, comparable to the 12 cm crown-rump length.
- Kaiser Permanente (pear): Another common fruit, emphasizing the baby’s overall pear-like shape at this stage.
The takeaway: your baby is growing at a normal pace regardless of which fruit your app uses. Your doctor tracks growth via ultrasound measurements, not by produce aisle logic.
Development Milestones at 17 Weeks
Beyond size, week 17 is a busy time for development. The fetus can move its eyes side to side, though the eyelids remain closed. Toenails are starting to grow, and fingerprints are forming on the fingers and toes—unique patterns that will stay with your baby for life.
Body fat is beginning to accumulate, and the bones and muscles are strengthening. This muscle development makes movements more coordinated. The baby may hiccup, causing small jerking motions that you might feel as flutters. WebMD notes that from head to heel, a 17-week fetus is about the length of a papaya, which includes the legs stretched out.
At this stage, the reproductive organs are developed enough to be visible on an ultrasound. However, whether you can learn the sex depends on the baby’s position and your provider’s policy.
| Development Area | Key Fact | Source |
|---|---|---|
| Crown-rump length | About 12 cm | NHS |
| Weight | 100–150 grams | MAM Baby |
| Head diameter | Approximately 4 cm | MAM Baby |
| Foot length | About 2 cm | MAM Baby |
| Eye movement | Eyes can move side to side | NHS |
| Toenails | Starting to develop | Mayo Clinic |
| Fingerprints | Forming on fingers and toes | What to Expect |
| Body fat | Beginning to develop | Kaiser Permanente |
These milestones are typical for 17 weeks, but individual variation is normal. Your ultrasound technician can give you the exact numbers for your baby’s growth.
Fetal Movement: What You Might Feel and When to Worry
Many people start feeling “quickening”—the first fluttery fetal movements—between 16 and 24 weeks. At 17 weeks, movements are becoming stronger as muscles and bones strengthen, but the baby is still small enough that early kicks may feel like gas or light tapping.
- Timing of first movement: Most people feel something between 16 and 24 weeks. For first pregnancies, it may be closer to 20 weeks or later.
- Type of movement: Rolling, flipping, and even hiccups (small jerks) are common at this stage. The baby is active even if you can’t feel every move.
- Visibility on ultrasound: Stronger muscles mean more purposeful movement. You may see the baby stretch, yawn, or suck a thumb during an ultrasound exam.
- When to call your midwife: If you haven’t felt any movement by 24 weeks, contact your midwife for a check of the baby’s heartbeat and movements.
Trust your instincts. If you notice a significant change in movement patterns—especially later in pregnancy—your provider wants to hear about it.
Your Body at 17 Weeks and What Helps
As the uterus continues to expand, you may notice your belly becoming more prominent. Meanwhile, hormones are preparing the breasts for milk production, which can increase blood flow and make veins more visible. Breast size can increase by 1–2 cup sizes, and some women feel a tingling or heaviness.
To manage these changes comfortably, consider a supportive bra and staying hydrated. The NHS notes that at 17 weeks, your baby’s measurement from crown to rump is about 12 cm crown to rump, a size that may start making your waistline feel noticeably different. Some women also experience round ligament pain as the uterus stretches—sharp twinges on one side of the belly that usually pass quickly.
If you haven’t had the anatomy scan (typically scheduled between 18 and 22 weeks), it’s coming up. This detailed ultrasound checks every major organ and confirms the size and position of the baby.
| Symptom or Change | What’s Happening |
|---|---|
| Larger belly | Uterus expands to accommodate a 12 cm baby |
| Breast growth (1–2 cup sizes) | Hormones prepare for milk production |
| Round ligament pain | Ligaments stretch as uterus grows |
| Veins more visible on chest/breasts | Increased blood flow |
The Bottom Line
At 17 weeks, your baby is roughly the size of a pomegranate—about 12 cm long and weighing 100–150 grams. Development is moving fast: eyes move, toenails form, fingerprints appear, and muscles grow stronger. Fruit comparisons vary because sources measure differently (crown-rump versus head-to-heel), but either way your baby is growing on track.
For personalized growth tracking and any concerns about movement before 24 weeks, your obstetrician or midwife can review your specific ultrasound measurements and discuss what’s normal for your pregnancy.
References & Sources
- WebMD. “Your Pregnancy Week by Week Weeks 17 20” WebMD notes that from head to heel, a 17-week fetus is the length of a papaya — about 10 inches (25.4 cm).
- NHS. “Week 17” At 17 weeks, the fetus is approximately 12 cm (4.7 inches) long from crown to rump.