Keeping informed with fetal ultrasound

USA Today (Society for the Advancement of Education), Feb, 1996

Sophisticated fetal ultrasound imaging plays a significant role in monitoring whether a baby is reaching critical growth and developmental milestones before birth. "It's the best physical you'll ever have, because the quantity and quality of information ultrasound reveals is astonishing," maintains George Leopold, chairman, Department of Radiology, University of California San Diego Medical Center.

Parents used to wonder if their baby had the right number of fingers and toes. "Today, modern ultrasound puts us light years beyond that. We can measure the fetus' size and estimate age extremely accurately just four to six weeks after conception. We can monitor fetal movements to see if the central nervous system is developing normally. We can see if the heart has four chambers and if the spinal cord is closed."

Some of what ultrasound has helped obstetricians understand about normal fetal development includes: * A fetus' patterns of movement change steadily and predictably. "At seven to eight weeks, the embryo's entire body jerks and twitches. At 13 to 14 weeks, we see movements in the limbs, not the entire body. By 20 weeks, we should see purposeful movements, like a hand opening and closing or sucking a thumb. If these movements aren't happening according to this schedule, we look for a problem in the central nervous system or metabolism," Leopold explains. * Although babies are born in all sizes and shapes, embryos are all the same size in the first few weeks after conception. So ultrasound often is used to resolve questions of size and date say, if a pregnant woman's size - too big or too small - doesn't jibe with her due date. "We can measure the head diameter and circumference and the length of the femur, the large bone in the leg, and very accurately determine the age. * With the common use of contraception and fertility drugs today, many women are unsure about menstrual cycle dates. "It's critical to know the appropriate delivery date," and not just for the doctor's convenience. "Before ultrasound helped us estimate age, women could be induced into labor too soon, before the baby was ready to be born, or allowed to carry a child past the time when the uterus could nourish it," Leopold points out, noting these situations have potentially heartbreaking results. * Growth disorders occur fairly often, with developmental retardation as common as one in 10 fetuses. Disorders usually develop in the third trimester, when the baby puts on two-thirds of his or her birth weight. Ultrasound is used to determine if there is a growth problem, and through research it is helping to find out why that occurs. The placenta is thought to be the culprit, for some reason not providing adequate nourishment. * Ultrasound can help determine if a mother seems "too big" because she is carrying an overly large fetus (she may have developed diabetes during pregnancy), or if there is simply an excess of amniotic fluid and the baby is really the right size. Depending on the answer, the obstetrician can make a better decision whether to intervene. * Growth disturbances are not uncommon in multiple births. For instance, in twins, one may be very large and one very small. Ultrasound, which can see blood flow in the vessels, can show whether the smaller twin is transfusing part of his or her blood supply from the larger twin. This can be treated by removing some amniotic fluid around the recipient twin, improving chances of survival. * On a psychological note, ultrasound actually jumpstarts maternal-fetal bonding, a phenomenon observed by Leopold and documented in psychiatric studies. "Ultrasound pictures are so good that even the patient can identify the baby's profile, arms, legs, and so on. At that point, the pregnancy becomes `real' for most mothers. The result is that they take better care of themselves - and their babies.