Frequent MD visits. Keep all your obstetrical appointments as each visit could make the difference between life and death for a growth restricted fetus. Aspirin if taken before the second trimester can prevent recurrent fetal growth restriction. A balanced diet, prenatal vitamins and avoidance of any/all exercise can also help your fetus maintain at least minimal growth.
Intrauterine Growth. Retardation can be symmetric: length , weight & head circumference all < 10th %ile for gestational age or asymmetric: only 1 or 2 growth parameters < 10th %ile.If it's from an abnormality in fetal development, e.g., a genetic syndrome or placental insufficiency, you can't do much. You can change some maternal factors (smoking, drinking, or using drugs but not others ( viral infections/ illness).