You are now in the seventh month of your pregnancy, so two-third of the waiting period to meet your baby is over. With the beginning of the third trimester, you are probably starting to experience a new set of symptoms along with the existing ones. Your baby is going through the final developmental phase, with preterm babies born in the 28th week having a 90% survival rate without any major neurological or physical defects .
Baby development in pregnancy week 28
Developing brain activity
The brain structure continues to get more complex with characteristic indentions and grooves developing along its surface . The increasing number of brain tissues in the 28th week contributes in higher brain activity levels. The fetal brain waves are also starting to show distinguishable sleep cycles when your baby is asleep. The rapid eye movement (REM) phase can be detected as well, indicating that your baby might have started dreaming by this week . The sleep cycles continue to get more distinct as the third trimester advances .
Your baby is still practicing breathing in and out while blood vessels are developing throughout both the lungs. The chemical agent surfactant is produced to prevent the air sacs from sticking with each other once the lungs begin to absorb oxygen after your baby’s birth. The maturing bronchial tubes also start dividing into smaller branches this week .
Sensory organ development
The eyes that opened last week are quite sensitive to bright light at this stage. Your baby can now blink or even turn his head in the womb if you shine a bright light on your belly from the outside . This is also the week when the irises are filling with pigment; however, the eye color is not permanent and can change until he is 1 year old .
Developing reflex actions
Your baby is now practicing various reflex actions including sucking harder than before, grasping anything that floats within range (usually the umbilical cord) and blinking his eyes . These will help him survive in the outside world once he comes out of the womb. Fetuses are often found sticking out their tongue after the 28th week. The exact reasons responsible for this action are still not known; but, it lets your baby taste the amniotic fluid as his taste buds are now matured enough .
The developing fat layers give the fetus an opaque and chubby appearance while fingernails begin to appear . Another noticeable change this week is the disappearance of the downy hair (lanugo) covering the fetus, as the job of regulating his body temperature is taken over by the fat underneath the skin layer .
Most babies move about 20 times within 30 minutes during their optimum activity period. Try to keep track of how much your baby is moving so you can detect any abnormality in his sleep and wake pattern as soon as possible. Consult your doctor to know the how much fetal movement is normal at this stage . In most cases, the babies settle into a head down position by this week, preparing for birth; but, they are likely to continue turning for a couple of more weeks .
Twin pregnancy week 28: fetal development
The 28th week is an important phase of twin fetal viability with preterm multiples born this week having equal chances of surviving as single babies (about 90%). However, they are still at considerable risk of long term complications like cerebral palsy, vision problems and chronic breathing difficulties .
How big is your baby?
Your baby is almost as big as a kabocha squash , being about 15 inches (38 cm) long from head to toe with his weight ranging around 2.25 pounds (almost a kilogram) .
28 weeks pregnant: weight gain, belly and body changes
The top of your uterus is about 3.5 inches (8.9 cm) above your bellybutton this week  while the fundal height (the distance from the top of the uterus to the top of your pubic bone), should be somewhere between 10 inches and 11.5 inches (26 cm and 29 cm). The relaxin hormone loosening your joints and the growing belly shifting your center of gravity are causing your to drop things, bump into your furniture and trip over more often. Wearing flat comfortable shoes and moving slowly are recommended to avoid falling and harming your baby .
You have probably gained between 17 and 25 pounds in the earlier two trimesters , with the ideal weight gain level for the third trimester being around 5 pounds . You might notice a thick yellowish fluid (colostrum) leaking from the nipples as your body is still preparing for breastfeeding .
28 weeks pregnant tests and ultrasound
A 2D ultrasound performed this week will show your baby to be quite active, moving his arms and legs a lot, grabbing he umbilical cord and sucking on his thumb. You can also opt for a 3D ultrasound at this stage to get the first picture for your baby album.
Your doctor might order a blood test this week for checking your hemoglobin levels to detect anemia , while your blood pressure levels will be measured during each prenatal visit. You may also have to take a glucose challenge test (if you have not already) to check for gestational diabetes.
Rh-negative women are given a Rhogam shot (an Rh immunoglobulin or RhIg injection) to prevent Rhesus factor sensitization in the mother in case the baby’s blood possesses the antigen .
Pregnancy week 28 signs and symptoms
- Round ligament pain
- Joint, hip and back pain
- Leg cramps
- Braxton Hicks contractions 
- Indigestion, bloating and heartburn
- Varicose veins and hemorrhoids 
- Frequent urination
- Shortness of breath and chest pain (due to the baby putting pressure on your lungs and ribs) 
- Swelling or edema of the arms and legs
- Stretch marks, especially on your belly, hips and thighs 
- Pelvic and tailbone pain
- Symphysis pubis dysfunction 
- Sharp pain down your sciatic nerve (sciatica) 
- Swollen or bleeding gums
- Itchy skin (around the growing belly, hips, and breasts)
- Sleep disturbance or insomnia 
- Restless leg syndrome (RLS) 
- Stuffy nose (due to the high pregnancy hormone levels increasing the blood flow to the nasal mucus membranes, causing them to swell) 
- Headache or migraine
- Fatigue and dizziness 
- Emotional changes and depression
When to call the doctor
- Frequent contractions getting closer together along with vaginal bleeding/spotting, losing the mucus plug or any change in the discharge, feeling pelvic pressure, lots of thin watery discharge and period-like cramping (might indicate premature labor) 
- Pain or burning during urination, lots of yellowish or green jelly-like or thick white discharge, lower back pain around one kidney, nausea and abnormally frequent urge to urinate (might indicate a urinary tract infection , kidney or yeast infection )
- Extreme fatigue and excessive thirst accompanied by increased urine output, severe nausea, dry mouth and sudden vision changes (might indicate gestational diabetes) 
- Severe diarrhea and/or vomiting persisting for over 24 hours
- Feeling less than 10 fetal movements in 2 hours during your baby’s active period (usually between 9pm and 1am) 
- Persistent headaches and lightheadedness with extreme fatigue, blurred vision, upper abdominal pain, rapid heartbeat and sudden swelling of the hands and face (might indicate high blood pressure or preeclampsia) 
- Unilateral swelling or one foot or ankle more swollen than the other (might indicate some serious underlying condition like a blood clotting disorder) 
Tips for a healthy pregnancy and baby
- Making sure to mention any concerns or queries you may have, regarding the growth of your baby or about labor and delivery, during your prenatal visits, which are likely to be more frequent now (twice a month)
- Including lots of iron rich foods, like spinach, tofu, beans, whole grain cereals, beef and chicken, in your daily diet as your baby needs even higher levels of iron in the last trimester ; your doctor might even recommend an iron supplement to prevent gestational anemia
- Stretching your legs for a few minutes or massaging them and cutting down on your caffeine intake can help to manage RLS 
- Now that your appetite has probably increased, following a diet containing plenty of fresh fruits and vegetables, whole grains, sugar free fruit juices and lean meat as these are rich sources of fiber, essential vitamins and minerals vital for proper fetal growth
- Going for your prenatal yoga classes and doing pelvic floor exercises to strengthen your pelvic muscles
- http://www.mayoclinic.org/healthy-living/pregnancy-week-by-week/expert-answers/swelling-during-pregnancy/faq-20058467 [/ref]