Final answer:
If the fundal height is at least 2 cm less than expected, the likely cause is Intrauterine growth restriction (IUGR), due to factors like placental insufficiency that impacts the adequate transfer of oxygen and nutrients to the fetus.
Step-by-step explanation:
If the fundal height is at least 2 cm less than expected, one possible cause is Intrauterine growth restriction (IUGR). IUGR refers to abnormally slow growth of a fetus, which might be attributable to maternal, fetal, or placental factors. Specifically, placental insufficiency is a leading cause of IUGR, which results in inadequate transfer of oxygen and nutrients to the fetus.
Other potential causes of reduced fundal height, such as fetal macrosomia and polyhydramnios, generally lead to an increased fundal height rather than a decrease. Normal variation in fetal growth could potentially be a benign reason for this measurement; however, a significant deviation usually warrants further investigation.
The normal growth of a fetus typically involves a linear increase in size during gestation until the last couple of weeks before birth. In cases of IUGR, this growth is compromised, leading to potential health issues like low birth weight and developmental delays, which can have long-lasting effects on the child's health.