You have now reached the 17th week of your pregnancy, and your little bundle of joy is growing steadily inside you. Have you felt your baby move yet? Do not worry much if you have not as the wait is almost over and you will be feeling those flutters any day now. Find out what changes are occurring in your baby as well as your body this week.
Baby development during pregnancy week 17
Fetal systems and organs
The placenta continues to grow, being almost as big as the fetus at this stage . It filters carbon dioxide and removes all wastes from your baby’s body while providing him oxygen and all the necessary vitamins, minerals, fats and proteins. The umbilical cord is also getting stronger and thicker .
The brain has started to regulate the fetal heartbeat while your baby continues to practice breathing movements by pushing amniotic fluid through his tiny lungs. The period between the 16th and 26th week are vital for the fetal lung development . Fats are forming just below the skin layer and will soon start accumulating in your baby’s body, constituting around two-thirds of his weight at birth .
Sensory organ development
The hearing is now developed enough for your baby to respond to sudden loud noises (e.g. doorbell or phone ringing) with a startle . In the meantime, the eyes continue to develop, although the eyelids remain fused shut.
With the head coming in proportion with the rest of the body, the legs are now the disproportionate part of the fetus. They seem longer and somewhat thinner than the arms, but will soon grow to suit the rest of the body . Your baby can even grip the umbilical cord with his little hands 
The ossification process continues from the last week as the spinal cord starts to grow a protective layer called myelin .
The deciduous or primary teeth have already formed in the gums and are set to grow out and play their part in the oral development .
External appearance and facial development
This is the week when those tiny eyes reach and settle in their final position in front of your baby’s head  while the ears are almost in place.
How big is the baby at 17th week of pregnancy?
Your baby is almost as big as an onion  this week, weighing around 5 ounces (140 gm) with a height of 5.1 inches (13 cm) .
Fetal movement at pregnancy week 17
At week 17, your baby can move his arms and legs while kicking and wriggling around. However, most first time mothers mistake these movements (quickening) for gas or stomach rumblings . You are more likely to recognize these early movements if it is your second or a subsequent pregnancy.
Your belly and body changes at pregnancy week 17
Your belly is growing gradually but steadily, finally giving you the baby bump you have been waiting for since the day you found out you were having a baby . The bump is likely to be more evident in case of a twin pregnancy. With the growth of the uterus, the other organs have to be pushed aside to make space. This allows you to feel the top of the uterus (which appears more round at week 17) easily while standing up .
You are probably gaining more weight at this stage (5-10 pounds being the average weight gain at this stage)  as the food aversions are easing a bit; so make sure to make healthy food choices to avoid unwanted weight gain .
Having shiny, lustrous hair is another positive body change during pregnancy. Your nails are also likely to grow much faster, but are likely to become brittle and flaky .
17 weeks pregnant ultrasound
An ultrasound scan can allow you to find out the gender of your baby, depending on how your baby is positioned within the womb . You can still see the developing blood vessels through his transparent skin as the fat layer is still too thin. A fetal Doppler can help you hear your baby’s heart beat, which is twice that of yours at 140-150 beats per minute .
Tests and exams in pregnancy week 17
No screening tests are performed at this stage unless it is a high risk pregnancy. Routine procedures include assessing the external appearance of the fetus with a regular or level one ultrasound to check for any congenital defects. However, it is not possible to detect all birth anomalies with this process. A level two ultrasound is performed in cases with abnormal level one report or negative screening results .
Amniocentesis , along with various blood and urine tests, are performed for screening neural tube defects and conditions like Down’s syndrome in high risk cases, such as the mother being over 35 years of age  or having a family history of the disorders.
Signs and symptoms of pregnancy week 17
The early pregnancy signs are probably gone by now, but they are replaced by a whole new set of uncomfortable symptoms:
- Acid reflux and heartburn 
- Gas and flatulence
- Increased sweating (due to the higher body temperature because of the raised blood volume) 
- Feeling hungry oftener than normal (some women may still experience loss of appetite)
- Increased vaginal discharge 
- Back pain
- Leg cramps
- Pain in the joints, ribs and hip
- Sciatic nerve pain 
- Feeling out of breath
- Round ligament pain 
- Getting affected by existing allergies (as pregnancy suppresses your immune system) 
- Itchiness, especially around the belly, breasts and back
- A dark line running down the middle of your abdomen (linea nigra) 
- Dark patches on the skin
- Visible veins, especially around the belly
- Dry skin and stretch marks
- Runny or stuffy nose along with other flu-like symptoms
- Headaches  and dizziness
- Emotional changes
- Swelling or edema mainly of the hands and feet
- Having weird, vivid dreams 
When to call the doctor?
- Any kind of vaginal bleeding or spotting with or without other symptoms like abdominal cramping, back pain or nausea 
- Clear or pale yellowish discharge (might indicate leaking amniotic fluid)
- Severe morning sickness (nausea and vomiting) and/or diarrhea that lasts for over a day (increases your risk of dehydration and weight loss while pregnant)
- Painful unilateral swelling or one leg more swollen than the other (might indicate a blood clotting disorder) 
- Severe itching without any rash or other apparent reason (might indicate a liver disorder like obstetric cholestasis) 
- Extreme back pain, leaking urine, pain during intercourse and symptoms of UTI (might indicate a tilted uterus) 
- Having symptoms like persistent headache, fainting, vomiting blood, period-like contractions and a racing heart or palpitations
- Considerable vision change or blurred vision (might indicate a complication like diabetes , hypertension or preeclampsia )
- Severe constipation along with considerable abdominal pain 
Tips for a healthy pregnancy and baby
- Drinking purified tap water as the fluoride in it is necessary for the teeth and enamel development of your baby 
- Following a diet containing fruits, vegetables and proteins rich in folic acid, vitamin C, omega-3 fatty acids and iodine (e.g. avocado, apples, leafy green vegetables, mushrooms soya beans and seafood) 
- Avoiding sudden movements like getting up too quickly from a sitting or lying position as such movements lead to a rapid drop in your blood pressure, increasing the risk of fainting. Moving slowly allows your body to adjust to the change in position .
- Avoiding wearing high heels as the growing uterus is changing the center of gravity of your body and low-heeled or flat shoes can provide better support .
- Nail paints do not cause any harm to you or your baby as long as you use it in a properly ventilated place, so you do not breathe in the fumes. It is a good option for managing the flaky, weak nails.
- Breaking up your daily meals into five or six small ones as having three large meals increases the chances of indigestion and heartburn .
- Consulting your doctor before using any over-the-counter medicines 
- Practicing proper sleeping positions (preferably on your right side)
- Joining a prenatal yoga class or doing some light workout such as pelvic floor exercises to avoid certain pains and stay in shape throughout your pregnancy 
- http://www.parenting.com/timeline/2nd-trimester-week-17 [/ref]