Pregnancy › Week by Week › Week 16
At 16 weeks your baby is about the size of an avocado. This is the start of the window when the first fluttery movements, called quickening, can begin, especially if this is not your first pregnancy.
Size
An avocado
crown to rump
Length
4.6 in
about 11.6 cm
Weight
3.5 oz
about 100 g
Your baby at 16 weeks
The eyes and ears are settling into their final spots, the heart is working hard, and movements are getting stronger.
Your baby is growing quickly and looking more like a newborn each week, with the face and the circulatory system both making real progress.
Eyes and ears. The eyes have moved to the front of the face and the ears are close to their final position on the sides of the head. The eyes can make small side to side movements now, and your baby can perceive some light through the still closed lids.
Heart at work. The heart is pumping around 25 quarts of blood a day, a number that will climb as your baby grows. The circulatory system and the umbilical cord are working steadily to deliver everything your baby needs.
Movement. Muscles are getting stronger, and your baby makes sucking motions and moves the arms and legs with more force. Those stronger movements are exactly what leads to the first flutters you may feel over the coming weeks.
How big is your baby at 16 weeks?
About 4.6 inches (11.6 cm) crown to rump and around 3.5 ounces (100 g).
Measurements are still taken crown to rump, from the top of the head to the bottom, since the legs stay curled in. Your baby is putting on length and a little weight now, and the body is looking well proportioned.
Your body at 16 weeks
Some people feel the very first flutters this week, along with a clearer bump and maybe a bit of backache.
If you feel a faint bubbly, flickering sensation low in your belly, that could be quickening, the first movements you can actually feel. It is easy to mistake for gas at first, and if you have not felt anything yet, that is completely normal too, since most first time mothers do not notice it until closer to 18 to 22 weeks. Once you do start feeling regular movement, it becomes a gentle daily reassurance, and your provider will talk with you later in pregnancy about paying attention to your baby’s usual pattern.
Your growing uterus and the extra weight it carries can bring some backache and the occasional sharp pull of round ligament pain low on the sides, and your center of gravity is beginning to shift. Good posture, supportive shoes, and a pregnancy pillow for side sleeping all help. Your bump may be clearly showing now, which for many people is the moment maternity clothes go from optional to genuinely comfortable, so it is a good time to sort out a few maternity pieces you actually like. Skin can look glowing or turn a little oilier thanks to hormones and increased blood flow.
What is normal, and when to call your provider
Backache and the first faint flutters can be normal now, but call your doctor or midwife the same day if you have any of these:
- Heavy bleeding, especially soaking a pad, or passing clots
- Severe or persistent abdominal or pelvic pain, or strong one sided pain
- A fever over 100.4°F (38°C)
- Fluid leaking or a gush from the vagina
- Painful or burning urination, which can signal an infection worth treating
- Fainting, or dizziness that does not pass
Your week 16 checklist
- Notice and enjoy any first flutters, but do not worry if you feel nothing yet
- Keep taking your prenatal vitamin with folate every day
- Support your back with good posture and a pregnancy pillow for sleep
- Round out your maternity clothes now that your bump is showing
- Schedule your anatomy scan if it has not been booked, it usually falls at 18 to 20 weeks
Appointments and tests around 16 weeks
The second trimester blood screen is often done around now, and the anatomy scan gets scheduled.
If you are having the second trimester maternal blood screen (sometimes called the quad screen), it is commonly drawn between 15 and 20 weeks, so it may fall around this visit. It estimates the chance of certain chromosomal conditions and neural tube differences and is a screen rather than a diagnosis. This is also the week many providers schedule the anatomy ultrasound, the detailed scan usually done between 18 and 20 weeks that checks your baby’s growth and development, and where you can often learn the sex if you want to. At a routine visit your provider will check your weight and blood pressure and listen for the heartbeat. As always, screening is your choice to accept or decline.
A few things worth having on hand now
A note for your partner
The first flutters are usually a private, inside feeling for a while, too faint for a hand on the belly to pick up, so if your partner says they felt something, share in the excitement even though you cannot feel it yet. Your turn comes in a few weeks as the movements get stronger. In the meantime, offering to rub a sore back or handling the anatomy scan scheduling is a real help.
You are not alone this week
Waiting for those first movements can stir up a lot of feeling, hope, impatience, and the very normal worry of wondering whether what you felt was real. Whether you have felt a flutter or nothing at all yet, both are perfectly normal at 16 weeks, and steadier movement is on its way.
16 weeks pregnant, common questions
What do the first baby movements feel like?
Early movements, called quickening, often feel like faint bubbles, flutters, or a light popcorn popping sensation low in your belly. They are easy to mistake for gas at first. Over the coming weeks they grow into clear, unmistakable kicks.
Is it normal to not feel the baby move yet at 16 weeks?
Completely normal. Most first time mothers do not feel movement until 18 to 22 weeks, and the position of your placenta can muffle it further. If this is a second or later pregnancy, you may notice it a bit earlier.
When is the anatomy scan?
The detailed anatomy ultrasound is usually done between 18 and 20 weeks, so week 16 is a common time to have it scheduled. It is a longer scan that checks your baby’s growth and development, and you can often find out the sex if you would like to.
Why does my back ache already?
Your growing uterus, extra weight, and shifting center of gravity all put new demands on your back. Good posture, supportive shoes, gentle movement, and a pregnancy pillow for side sleeping can all ease it. Mention any severe or persistent pain to your provider.
Sources
- American College of Obstetricians and Gynecologists (ACOG), second trimester care and fetal movement guidance.
- Mayo Clinic, Fetal development: the 2nd trimester.
- MedlinePlus, National Library of Medicine (NIH), Fetal development and prenatal care.
Medical disclaimer: This page is for information and education only and is not a substitute for professional medical advice. Every pregnancy is different. Always follow the guidance of your doctor, midwife, or qualified provider, and contact them with any concerns.