18th Week Growth...

How your baby's growing:
Head to bottom, your baby is approximately 5 1/2 inches long (about the length of a large sweet potato) and she weighs almost 7 ounces. She's busy flexing her arms and legs — movements that you'll likely start noticing more and more. Her blood vessels are visible through her thin skin and her ears are now in position and stand out from her head. Myelin (a protective covering) is beginning to form around her nerves, a process that will continue for a year after she's born. If you're having a girl, her uterus and Fallopian tubes are formed and in place. If your baby is a boy, his genitals are noticeable, though he may hide them from you during an ultrasound.
Your baby's brain is growing rapidly. By this stage, all of the major areas have been differentiated. The cortical layers, which govern specific brain functions, are beginning to form. The fetus may exhibit signs of a primitive body language in utero, such as recoiling when the needle for the amniocentesis comes too close for comfort. Within the next few weeks, she'll be able to hear voices outside the womb and respond positively to music or loving words. It's time to fine-tune your singing and storytelling skills!
By now, the bones of Baby's inner ear and the nerve endings from the brain have developed enough so that your baby can probably detect sounds clearly. Experts believe that one of the most comforting sounds she hears is Mom’s heartbeat. She may also hear your voice, your stomach rumbling, and the sound of blood moving through the umbilical cord to and from the placenta, which is now almost as big as she is. And that's not all! Here's what else is happening to baby this week:
*She will begin to swallow, and may even feel thirsty sometimes. Some experts think thirst may trigger your baby to swallow. Since amniotic fluid is constantly being produced, Baby’s swallowing of excess fluid helps keeps it at a constant level.
*Baby's chest will continue to move up and down to mimic breathing, but she's not breathing air — just swallowing and inhaling amniotic fluid. This is a normal part of your baby’s development—this intake of amniotic fluid will not harm her.
*If baby is a girl, the vagina, uterus, and Fallopian tubes will be in place by the end of the week.

How your life's changing:
Bigger, more comfortable clothes are a must now as your appetite and waistline increase. Look for specially designed maternity clothes that can accommodate your expanding belly.You may have heard that it's best to lie on your left side during your last two trimesters. Here's why: When you lie on your back, your uterus can compress your pelvic veins — in particular, the inferior vena cava, the vein that returns blood from the lower half of your body back to your heart. Lying on your left side helps remove this pressure. Try placing a pillow behind you, or under your hip or leg for comfort.Your cardiovascular system is undergoing dramatic changes, and during your second trimester your blood pressure is probably lower than usual. Don't spring up too fast from a lying or sitting position or you might feel a little dizzy. If you haven't already, you'll probably have an ultrasound done sometime this trimester (usually between 16 and 20 weeks). This painless procedure helps your practitioner check how your baby's growing, screen for certain birth defects, check the placenta and umbilical cord, determine whether the due date you're working with is accurate, and see how many babies you're carrying. During the exam, you might see your baby moving around or sucking her thumb. Bring your partner along, and be sure to ask for a printout for your baby's first photo album!
On average, pregnant moms have gained about 10 or 11 pounds by now. It's a good idea to gain weight gradually; by not putting on a lot of weight all at once, your body won't be as stressed and you may have an easier time delivering the baby. (Plus you'll have fewer extra pounds to lose afterwards!) If you're having difficulty getting a good night's sleep because of this added weight and the resulting discomfort, try urinating before going to bed, propping yourself up with pillows in bed, and resting on your left side.
This week you may also want to prepare yourself for a mid-pregnancy ultrasound, which is often recommended sometime during the second trimester, usually between 18 and 22 weeks. This test can help your doctor assess fetal growth and development, screen for certain birth defects, check the placenta and umbilical cord, and determine whether the projected due date is accurate. At this early date, the test may also be able to detect gender, but only if the baby is in a position where genitals are visible.