Your Baby Bump: What Your Growing Belly Reveals About Baby

Katie Cowan knows all about having an LFD baby. Her first child weighed more than 10 pounds at birth, and her second baby is measuring large also. "I didn't really realize that I was so huge during my first pregnancy until the end. When the week of my due date arrived and a woman in the supermarket asked me if I was having twins, I knew that I was abnormally large. I am now expecting my second baby and I am 26 weeks along. Just last week a man stopped me in the street and said, 'Due any day, aren't you?' I am getting used to the comments and the size of my belly now." Cowan adds that she also blames the large babies on her husband's genetics, since his mother had gigantic babies, the smallest of which was 9 pounds, 10 ounces.

Incidentally, Cowan's doctor isn't concerned about the size of her baby either, yet her doctor doesn't want Cowan to have a 10-pound baby as she did last time. So, Cowan will be induced at least a week early in this pregnancy.

Large babies seem to run in the family for Katie Cowan, but for most LFD babies this isn't the norm. "One of the most common incidences of large-for-dates babies is in mothers who have gestational diabetes: the excess of blood sugar passing through the placenta are turned into fat stores under the baby's skin," says Hunter. "Women who are themselves overweight are also more likely to have large-for-dates babies."

The most important implication with a LFD baby is that the mother will be unlikely to have the baby vaginally because of the disproportion between the size of the baby's head and the mother's pelvis. In these cases, the mother may be induced or given a preterm Cesarean section to avoid further complications. In such cases, the baby might require special care due to its premature birth—despite its large size.

On the other extreme are SFD babies. Hunter says that a baby may grow more slowly than expected for a number of reasons. These may be connected with the mother's lifestyle or general state of health. For example, if the mom-to-be is underweight and fails to gain weight during pregnancy, exercises excessively, or if she has an ongoing illness (or becomes ill during pregnancy), she may have a small-for-date baby. Complications of pregnancy, such as repeated vaginal bleeding or placenta previa, also increase the likelihood of having an SFD baby.

Hunter adds that if the mother's lifestyle is implicated, it is possible to improve the fetus' growth rate if the mother has the willpower to make the changes. If the mother engages in a healthy lifestyle, the fetus can potentially catch up completely with its expected weight. And if the problem is related to illness or a complication, good nutrition and as much rest as possible—coupled with safe treatment for specific conditions or complications—are the best ways of improving fetal growth.