Your baby has a lot more growing to do before birth, but he is getting bigger every day. He is now 5 to 5 and a half inches from crown to rump, and weighs about 5 ounces.
By week 18, your baby's bones are beginning to ossify, as cartilage hardens into bone. If you could see a picture of your baby now, he would look more like an infant -- and less like the alien of just a few weeks ago. By this point in pregnancy, your baby's face has grown chubbier and rounder, and his features are becoming increasingly refined and well proportioned. The eyes are now in the proper place, as are the ears. In every respect, your baby is becoming more and more himself: as of week 18, the pads on the ends of his fingers will begin to develop distinctive fingerprints.
Around this week, a baby's ears are sufficiently developed that he can hear for the first time. The womb is a protected environment, but it is not a particularly quiet one: babies can hear their mother's heartbeat, as well as the rush of blood through the umbilical cord. There is evidence that unborn babies come to recognize their mother's voice, and are disturbed by sudden, loud noises.
Don't hesitate to talk and sing to your baby, if you aren't doing so already. Most women find that, during the course of pregnancy, they develop a powerful intimacy with their unborn child. You are probably already speculating about what your child will look like, and what kind of personality he will have. Will he have your husband's nose, or your distinctive coloring? Will he inherit your Uncle Max's wicked sense of humor, or his grandmother Lila's artistic talent?
You've probably been considering various names, and jotting down some of your top choices. Try these out in your conversations with your baby, and see if any particular name seems to fit.
You may want to write down your observations and impressions of your unborn child. Many couples keep a pregnancy journal, in which they also record milestones, like the first time they heard the baby's heartbeat, or felt him move. You can tape your baby's ultrasound photos in the journal, and maintain a running list of baby's names.
If you attend a childbirth or parenting class, keep notes of key points in your journal. At your baby shower, ask friends and family members to write messages to you and your baby. Have your partner take periodic photos of your growing belly, and include these in your journal as well. Before you are in the early stages of labor, when you are waiting for the baby to make an appearance, you and your partner can jot down your feelings and observations, hopes and fears. Later, when you are up to it, your pregnancy journal is also a good place to write about your birth experience.
Between the 18th and 20th weeks, many doctors order an ultrasound to check on how the baby is doing. You can include the results of the ultrasound in your baby's scrapbook.
Pregnancy and childbirth are such intense experiences that it is probably inconceivable to you now that you will forget a minute of it. In fact, becoming a parent is even more intense and all-consuming, and it will be likely to drive many things out of your mind. Moreover, one day your child will be old enough to enjoy seeing the photos and hearing the memories, and you'll be very glad that you kept a record to share with him.
If you haven't done so already, you could start looking for a pediatrician or family doctor for your baby. Talk to friends, neighbors and colleagues, and collect as many referrals as you can. But don't go by word of mouth alone; this is an important decision -- and a highly individual one. Make appointments to meet with a few doctors, and bring along a list of questions.
You'll likely make your decision in part on how much you like a particular physician as an individual, but don't base your choice on charisma alone. Find out basic information about the practice. You'll want to know what insurance the office accepts, the availability of care on the weekends and at night, and the names of hospitals with which the practice is affiliated.
You should also ask each doctor about parenting issues that are important to you -- like breast feeding, immunizations, or nutrition -- and make sure that your views are compatible. During your visit, observe how the office operates, and be aware of the little details. Is the office staff pleasant and helpful, or brusque and stressed out? Is the atmosphere kid-friendly? Is it easy to get to and is there plenty of parking nearby? Can you get a same-day appointment for urgent care? Do they have weekend or evening hours?
This isn't a decision to be made lightly. Particularly in the first years of your child's life, your baby will see the doctor frequently -- not only for regularly check-ups, but for everything from ear infections to strep throat to stitches. And this could be a very long relationship: if all goes well, your child could be seeing the same physician for many years to come.
Campbell, Stuart MD. Watch Me Grow. St. Martin's Griffin.
Supple, William F., Jr, Ph.D, Becoming A Baby: How Your Baby Grows From Day-to-Day, Picket Fence Publishing.
Curtis, Glade MD and Judith Schuler. Your Pregnancy Week by Week. Da Capo Press.
Spencer, Paula, Parenting Guide to Pregnancy and Childbirth, Ballantine Books.
American Academy of Family Physicians, Pregnancy Calendar, Week 18. http://kidshealth.org/
Kidshealth.org. The Senses and Your Newborn. August 2008. http://kidshealth.org/parent/growth/senses/sensenewborn.html