Pregnancy week 16
At week 16 of pregnancy, the fetus is around 4 1/2 inches and at about 3 ounces. If the state of pregnancy hasn’t been apparent before, it will become apparent at this point. Although not nearly as round at week 16 as a pregnant woman will be in the further weeks, maternity clothes are more of a consideration than ever before. Small movements made by the baby are reverberated through the stomach and can be felt at week 16. These movements are referred to as “quickening” and are often noticed earlier by mothers who have given birth before.
At this point the baby is continuing to develop at a swift and steady speed. The neck becomes able to support the head at a straighter angle than before, the eyes are ears are finalizing their migration to their appropriate areas, the heart is driving 25 quarts of blood through the baby’s body every day, and hair is beginning to grow on the baby’s head. Eyebrows and eyelashes are also growing along with toenails. Also at this point, the legs become longer than the baby’s arms while the newly secured umbilical cord provides necessary nutrients. The bladder is urinating once around every 45 minutes.
The skin is translucent and the baby looks abnormally bony because it has not yet developed a layer of fat. The ianguo keeps the body temperature of the baby constant until the layer of fat is developed. This is also when the baby can hear sounds for the first time.
Also at week 16, numerous tests are conducted. An alpha-fetoprotein test is conducted between pregnancy weeks 16 to 18 in order to determine high levels of AFP in the blood. If high levels are detected, an amniocentesis or ultrasound will probably be ordered by the physician in order to corroborate the results. Amniocentesis is used to reveal genetic birth defects. Since the procedure carries the potential for miscarriage, it is often a last resort. The pregnant woman’s skin is taunt and retaining fluid during this stage in the pregnancy. The increased blood flow can give the appearance of a certain “glow.”
Current guidance (today's medical sources): Around week sixteen many people begin to feel the first faint flutters of movement, known as quickening, though this varies and often comes later in a first pregnancy. The baby's eyes can move and it may make sucking motions. The maternal blood volume continues to rise to support the growing baby.
Contact your healthcare provider promptly about heavy vaginal bleeding, severe or persistent abdominal pain, a high fever, severe or sudden headache, vision changes, or fainting. Seek urgent care if you are worried — these can be signs that need medical attention.
Sources: NHS — 16 weeks pregnant; Mayo Clinic — Fetal development: The 2nd trimester; ACOG — Special Tests for Monitoring Fetal Health. Informational only. See our sources & medical-review policy.
Frequently asked questions
How many months is 16 weeks pregnant?
Week 16 falls in the second trimester. Pregnancy is usually counted in weeks (about 40 in total) rather than months, because weeks are more precise.
What is happening to the baby at 16 weeks?
The baby's eyes can move and it may make sucking motions; the heart pumps a substantial amount of blood daily.
What symptoms are common at week 16?
Some people begin to feel first flutters of movement (quickening). Symptoms vary a lot from person to person; discuss anything that worries you with your healthcare provider.
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See the week-by-week guide →Informational only — not medical advice. Pregnancy Week to Week is a general educational reference. It is not a substitute for professional medical care, diagnosis, or treatment. Every pregnancy is different: always consult your doctor, midwife, or other qualified healthcare provider about your own pregnancy, and never disregard or delay professional advice because of something you read here. In an emergency, contact your maternity unit or local emergency number immediately.