17 Weeks Pregnant: Fetal Development & Body Changes

How Big Is My Baby at 17 Weeks Pregnant?

At 17 weeks pregnant, your baby measures approximately 15 centimeters (about 6 inches) from crown to rump and weighs around 135 grams (4.7 ounces). The baby is now about the size of a pomegranate or turnip. The body is growing rapidly to achieve better proportions, as the head was much larger relative to the body earlier in pregnancy.

Week 17 represents an exciting time in your baby's development. During the first trimester, the head was disproportionately large compared to the rest of the body, a normal feature of early fetal development. Now, the body is experiencing a growth spurt to catch up, and by the time your baby is born, the proportions will be much more balanced. This rapid body growth is supported by the placenta, which is now fully functioning and efficiently delivering nutrients and oxygen to your growing baby.

The skeletal system continues to develop, with the rubbery cartilage that makes up much of the skeleton gradually hardening into bone through a process called ossification. This process will continue throughout pregnancy and even into childhood. Your baby's ears have moved to their final position on the sides of the head, and the eyes, which were previously located on the sides of the head, have migrated to face forward. While the eyelids remain fused shut, the eyes can now sense light.

One of the most significant developments at 17 weeks is the formation of fingerprints. The unique patterns on your baby's fingertips are already forming, creating an identity that will remain unchanged throughout their entire life. These intricate patterns are influenced by genetic factors and the baby's position in the womb, making each set of fingerprints truly unique.

Brown Fat Development

A crucial development at week 17 is the accumulation of brown fat (also called brown adipose tissue) in your baby's body. Unlike the white fat that serves as energy storage, brown fat has a specialized function: generating heat. Brown fat gets its distinctive color from its high concentration of mitochondria and blood vessels.

After birth, newborns cannot shiver to generate warmth like adults can. Instead, they rely on brown fat to maintain their body temperature through a process called non-shivering thermogenesis. Brown fat is typically deposited around the neck, shoulders, and spine, where it can efficiently warm the blood flowing to vital organs. While some of this brown fat will gradually decrease as your baby grows and develops other methods of temperature regulation, it plays a vital role in those first crucial weeks of life outside the womb.

Protective Vernix and Lanugo

Around this time, your baby also begins developing a protective coating of vernix caseosa, a waxy, cheese-like substance that covers the skin. This coating serves multiple important functions: it protects the delicate skin from the amniotic fluid, provides insulation, and aids in the birth process by acting as a natural lubricant. The vernix is held in place by lanugo, a fine, downy hair that covers much of the baby's body.

What Symptoms Are Normal at 17 Weeks Pregnant?

Common symptoms at 17 weeks include increased sweating, swollen and bleeding gums, nasal congestion, nosebleeds, fatigue, breast tenderness, and constipation. These symptoms occur due to hormonal changes and increased blood volume. Most symptoms are normal and manageable with self-care measures.

During pregnancy, your body undergoes remarkable physiological changes to support the growing baby. These changes can manifest as various symptoms that, while sometimes uncomfortable, are generally normal parts of pregnancy. Understanding why these symptoms occur can help you manage them more effectively and know when to seek medical advice.

The second trimester is often considered the most comfortable period of pregnancy, as the intense fatigue and nausea of the first trimester typically subside. However, new symptoms may emerge as your body continues to adapt. The total blood volume in your body increases by approximately 45-50% during pregnancy to meet the demands of the growing fetus and placenta. This significant cardiovascular change is responsible for many of the symptoms you experience.

Increased Sweating

Many pregnant women notice they sweat more than usual during pregnancy, and week 17 is no exception. This increased perspiration is a direct result of the expanded blood vessels and significantly increased blood circulation throughout your body. Your metabolic rate has increased to support the growing baby, generating more body heat. The body responds by increasing sweat production to help regulate temperature.

To manage increased sweating, wear loose, breathable clothing made from natural fibers like cotton. Stay well-hydrated by drinking plenty of water, and avoid overheating by staying in cool environments when possible. Use a gentle, fragrance-free antiperspirant if needed, and shower as often as necessary to feel comfortable.

Swollen Mucous Membranes

Pregnancy hormones, particularly estrogen, cause the mucous membranes throughout your body to become more swollen and vascular. This affects several areas:

• Gums: Swollen gums (pregnancy gingivitis) may bleed more easily when you brush or floss. This affects approximately 50-70% of pregnant women. Maintain good oral hygiene and consider using a soft-bristled toothbrush.
• Nasal passages: Nasal congestion, often called "pregnancy rhinitis," can make breathing through your nose difficult. You may feel like you have a constant cold.
• Nosebleeds: The increased blood supply to the nasal membranes makes blood vessels more fragile and prone to bleeding. Nosebleeds are common and usually not cause for concern.

To manage nasal congestion, try using a saline nasal spray, using a humidifier in your bedroom, and elevating your head while sleeping. For nosebleeds, apply gentle pressure to your nostrils and tilt your head slightly forward. If nosebleeds are frequent or heavy, consult your healthcare provider.

Other Common Symptoms

Beyond the symptoms caused by increased blood flow and hormonal changes, you may also experience:

• Round ligament pain: Sharp or stabbing pains in the lower abdomen or groin area as the ligaments supporting the uterus stretch
• Breast changes: Continued tenderness, enlargement, and darkening of the areolas as your body prepares for breastfeeding
• Constipation: Hormonal changes slow down digestion, and the growing uterus can put pressure on the intestines
• Headaches: Hormonal fluctuations and increased blood volume can trigger headaches
• Dizziness: Changes in blood pressure and blood sugar levels can cause occasional lightheadedness

When Should I Have My Ultrasound Scan?

The detailed anatomy ultrasound (20-week scan) is typically performed between weeks 18-22 of pregnancy. By week 17, you should expect to receive your appointment invitation. This scan checks fetal development, confirms the due date, determines if there is more than one baby, and can detect certain structural abnormalities.

The second trimester ultrasound, often called the anatomy scan, anomaly scan, or 20-week scan, is one of the most comprehensive prenatal examinations. While it's commonly referred to as the 20-week scan, it's typically performed anytime between weeks 18 and 22, depending on your healthcare system and provider. By week 17, many women have already received their appointment invitation, and if you haven't, you should expect it soon.

This ultrasound examination is more detailed than earlier scans and serves several important purposes. The sonographer or physician performing the scan will systematically examine your baby from head to toe, checking multiple organ systems and physical structures. This comprehensive assessment typically takes 30-45 minutes, though it may take longer if the baby is in a position that makes visualization difficult.

What the Anatomy Scan Examines

During the detailed anatomy ultrasound, the healthcare provider will assess:

• Head and brain: The skull shape, brain structures, and spaces containing fluid around the brain
• Face: The profile, lips, and palate to check for cleft lip or palate
• Spine: Each vertebra is examined to check for spina bifida and proper spine development
• Heart: The four chambers, major blood vessels, and heart rhythm are carefully evaluated
• Abdominal organs: Stomach, kidneys, bladder, and abdominal wall
• Arms and legs: Bone length and number of fingers and toes
• Placenta: Position and health of the placenta
• Amniotic fluid: The amount of fluid surrounding the baby

The scan will also confirm your due date by measuring the baby and can determine if you are carrying more than one baby. Many parents also choose to learn the sex of their baby during this scan, as the external genitalia are usually visible by this point. However, you can choose not to find out if you prefer to wait until birth.

Understanding Prenatal Screening

Prenatal screening and diagnostic tests provide information about your baby's health and development. It's important to understand the difference between screening tests and diagnostic tests:

Screening tests estimate the probability of a condition but cannot provide a definitive diagnosis. They include blood tests, combined first-trimester screening, and detailed ultrasound examinations. A positive screening result indicates increased risk and may lead to offering diagnostic testing.

Diagnostic tests provide definitive answers about whether a specific condition is present. These include amniocentesis (testing the amniotic fluid) and chorionic villus sampling (CVS). These tests carry a small risk of complications and are typically offered when screening indicates elevated risk or for other medical reasons.

What Vaccinations Are Recommended During Pregnancy?

Several vaccinations are recommended during pregnancy to protect both mother and baby. COVID-19 and influenza vaccines are recommended after week 12 to reduce severe illness risk. The whooping cough (pertussis) vaccine is recommended from week 16 onwards to protect your newborn in their first weeks of life.

Vaccination during pregnancy is an important aspect of prenatal care that protects both you and your baby. Pregnant women are at increased risk of severe illness from certain infectious diseases, and some vaccines can provide protection to your newborn before they're old enough to be vaccinated themselves. At week 17, you're now in the recommended window for several important vaccinations.

When you receive a vaccine during pregnancy, your body produces antibodies that can cross the placenta and provide your baby with passive immunity. This protection is especially crucial during the first few months of life when your baby's immune system is still developing and they're too young to receive most vaccinations.

COVID-19 Vaccination

COVID-19 vaccination is strongly recommended for pregnant women, typically after week 12 of pregnancy. Research has shown that pregnant women who contract COVID-19 are at higher risk of severe illness, hospitalization, and complications such as preterm birth compared to non-pregnant women. The vaccines have been extensively studied and are considered safe during pregnancy.

Both mRNA vaccines (Pfizer-BioNTech and Moderna) are recommended options during pregnancy. The vaccination provides protection not only to you but also to your baby through the transfer of antibodies across the placenta. Studies have shown that babies born to vaccinated mothers have antibodies against COVID-19 present at birth.

Influenza Vaccination

If flu season is approaching or ongoing, the influenza vaccine is recommended for all pregnant women. Pregnancy increases the risk of serious flu complications, and getting vaccinated reduces this risk significantly. The flu vaccine is safe during any trimester of pregnancy and cannot give you the flu.

Beyond protecting yourself, getting the flu vaccine during pregnancy provides protection to your baby during the first months of life. Infants under 6 months cannot receive the flu vaccine, so maternal antibodies transferred during pregnancy and through breastfeeding are their primary source of protection.

Whooping Cough (Pertussis) Vaccination

The Tdap vaccine, which protects against tetanus, diphtheria, and pertussis (whooping cough), is recommended during each pregnancy, ideally between weeks 16 and 32. Whooping cough can be life-threatening for newborns and young infants who are too young to be fully vaccinated against it.

Whooping cough begins with cold-like symptoms but progresses to severe coughing fits that can last for weeks. In newborns, it can cause breathing difficulties, pneumonia, and in severe cases, death. By getting vaccinated during pregnancy, you produce antibodies that cross the placenta and provide your baby with protection during their most vulnerable first weeks of life.

What Body Changes Can I Expect at 17 Weeks?

At 17 weeks, your uterus has grown to about the size of a cantaloupe and is rising above your pelvis. You may notice a visible baby bump, weight gain of 2-5 kg so far, darker nipples, and a visible linea nigra (dark line on your abdomen). Your center of gravity is shifting, which may affect your balance.

By week 17, many of the internal changes of pregnancy are becoming externally visible. Your uterus, which started as approximately the size of a pear, has now grown to about the size of a cantaloupe melon. It's rising out of the pelvis and pushing your intestines aside, which is why your baby bump is becoming more noticeable. The fundus (top of the uterus) can now be felt about halfway between your pubic bone and navel.

The growing uterus and changing hormones affect nearly every system in your body. Understanding these changes can help you adapt and know what to expect in the coming weeks. While every pregnancy is unique, certain changes are common at this stage.

Your Growing Belly

If this is your first pregnancy, you may have just started showing or are about to. Second-time mothers often show earlier because their abdominal muscles have been stretched before and accommodate the growing uterus more readily. The shape and size of your bump depend on many factors, including your body type, muscle tone, the position of your uterus, and the baby's position.

Don't compare your bump size to other pregnant women, as there's significant variation in how and when women show. What matters is that your healthcare provider confirms your baby is growing appropriately through measurements and ultrasound examinations.

Skin Changes

Pregnancy hormones cause various changes to your skin. The linea nigra, a dark vertical line running from your navel to your pubic bone, may become visible. This line exists in everyone but becomes more prominent during pregnancy due to increased melanin production. It typically fades after delivery.

Your nipples and areolas have likely become darker, which is believed to help your newborn baby locate them for breastfeeding. Some women also develop chloasma or "mask of pregnancy," darker patches on the face, particularly on the cheeks, forehead, and upper lip. Sun exposure can worsen these patches, so wearing sunscreen is recommended.

Weight Gain

By week 17, you may have gained approximately 2-5 kilograms (4-11 pounds), though this varies considerably. Weight gain during pregnancy comes from the baby, placenta, amniotic fluid, increased blood volume, breast tissue, uterine growth, and some stored fat for breastfeeding.

Recommended weight gain during pregnancy depends on your pre-pregnancy body mass index (BMI). For women with a normal BMI, the recommended total weight gain is typically 11-16 kg (25-35 pounds). Your healthcare provider can give you personalized guidance based on your individual circumstances.

When Should I Contact My Healthcare Provider?

Contact your healthcare provider if you experience vaginal bleeding, severe abdominal pain, signs of infection (fever, burning urination), severe headaches with vision changes, or significant changes in fetal movement. For emergency symptoms like heavy bleeding or severe pain, seek immediate medical attention.

While most symptoms during pregnancy are normal and expected, some warrant prompt medical attention. Knowing when to seek care can help ensure the best outcomes for you and your baby. Don't hesitate to contact your healthcare provider if something doesn't feel right - your concerns are always valid, and it's better to check than to wait.

Regular prenatal appointments are important for monitoring your health and your baby's development. At these appointments, your healthcare provider will check your blood pressure, weight, urine, and measure your fundal height. They'll also listen to your baby's heartbeat and address any questions or concerns you have.

Warning Signs Requiring Immediate Attention

Seek immediate medical care if you experience any of the following:

• Vaginal bleeding: Any bleeding, especially if heavy or accompanied by pain
• Severe abdominal pain: Intense, persistent pain that doesn't improve with rest
• Fluid leaking from vagina: Could indicate ruptured membranes
• High fever: Temperature above 38 C (100.4 F) could indicate infection
• Severe headache: Especially with vision changes, swelling, or upper abdominal pain (could indicate preeclampsia)
• Signs of blood clot: Severe leg pain, swelling, warmth, or redness in one leg

Tips for Week 17 of Pregnancy

Focus on maintaining a healthy lifestyle with balanced nutrition, regular gentle exercise, and adequate rest. Stay hydrated, practice good dental hygiene to prevent pregnancy gingivitis, start thinking about childbirth classes, and begin planning for nursery or baby supplies. Connect with other expecting parents for support.

As you move through the second trimester, you're likely feeling more energetic than during the first trimester. This is an excellent time to establish healthy habits, prepare for your baby's arrival, and take care of your physical and emotional well-being. Here are some practical tips for week 17 and beyond.

Nutrition and Hydration

Continue eating a balanced diet rich in fruits, vegetables, whole grains, lean proteins, and healthy fats. Key nutrients during pregnancy include:

• Folate/Folic acid: Important for neural tube development (leafy greens, fortified cereals)
• Iron: Supports increased blood volume (lean red meat, beans, fortified cereals)
• Calcium: For baby's bone development (dairy, fortified plant milks)
• DHA: Supports brain development (fatty fish, supplements)
• Vitamin D: For bone health and immune function (sunlight, supplements)

Stay well-hydrated by drinking at least 8-10 glasses of water daily. Proper hydration helps maintain amniotic fluid levels, prevents constipation and urinary tract infections, and supports the increased blood volume of pregnancy.

Physical Activity

Regular, moderate exercise during pregnancy offers numerous benefits, including improved mood, better sleep, reduced back pain, and easier labor and recovery. Safe activities for most pregnant women include walking, swimming, prenatal yoga, and low-impact aerobics. Aim for 150 minutes of moderate activity per week, but always listen to your body and avoid overexertion.

Avoid activities with a high risk of falls or abdominal trauma, such as contact sports, skiing, or horseback riding. After the first trimester, avoid exercises that involve lying flat on your back for extended periods, as this can reduce blood flow to your uterus.

Planning Ahead

The second trimester is an ideal time to start planning for your baby's arrival:

• Research and register for childbirth education classes
• Begin thinking about nursery setup and baby supplies
• Review your health insurance coverage for pregnancy and newborn care
• Consider your parental leave options and start planning
• Connect with other expecting parents through classes or support groups
• Start creating a birth plan if you wish to have one