At 18 weeks pregnant, your baby is now 5.6 inches long from crown to rump. This is comparable to the length of a medium-sized banana pepper. Your little bundle of joy now weighs almost 7 ounces. Can you believe how big your baby is getting? Until this point in your pregnancy, the placenta was larger than your baby's body. This is no longer the case. Your baby has outgrown the placenta, and he or she will continue to get larger. The placenta still grows, but not as rapidly as it did earlier in your pregnancy.  Your baby's heart has developed enough to show signs of defects. Ultrasound can be used to help detect any structural abnormalities that might exist in the heart. Fortunately, most babies will be born without any congenital abnormalities (birth defects). If an early ultrasound does detect something abnormal, you can plan ahead for any interventions or surgeries that may be necessary to support your newborn baby after birth.  Your little one is starting to produce a protective covering along the nerves, called myelin. This substance will be continuously produced through the ninth month. Your baby's genitals should be distinguishable. You should be able to find out if it's a boy or a girl now.  Your baby's skin is still soft and smooth at this point. But in the next few weeks, your little one will develop his or her first fingerprint and toe print patterns! This is quite an exciting development, because no two individuals (not even identical twins) have fingerprints that are exactly the same. Your baby's lungs continue to develop. Although the lungs remain immature and won't be fully developed until your baby is full-term, the trachea (or windpipe) has branched into two main bronchi (airways). From this week until 28 weeks pregnant, each of the two bronchi will branch even further into smaller bronchioles.  The outer ear is well developed and your baby can already pick up sounds from outside the womb. For this reason, don't be shocked if your baby suddenly kicks you at the sound of a loud car horn or vacuum cleaner. Your baby's inner ears continue to develop, but they won't be completely mature until the end of your second trimester.  Ossification, or the hardening of your baby's bones, continues this week. Throughout your baby's body, calcium continues to strengthen the bones. Your little one's tooth buds continue to harden, and the jaw is continuing to grow.  With each week that passes, the umbilical cord is getting stronger and thicker than ever. It continues to grow to transport the blood and nutrients that your growing baby needs.