Final answer:
The fetus depends on the mother for blood glucose control because insulin does not cross the placenta (option c) . In diabetic patients, the negative feedback loop regulating blood sugar is disrupted, requiring insulin injections to manage glucose levels.
Step-by-step explanation:
A major concern for the diabetic patient who is pregnant is the effect her blood glucose control has on the fetus. The fetus is totally dependent on the mother for this control because insulin does not cross the placenta. This is crucial to understand because the placenta supplies the fetus with necessary nutrients and oxygen from the mother's blood. However, the fetus has its own pancreas which produces the insulin it needs to regulate its blood sugar levels. If the mother's blood glucose levels are high, the fetus's pancreas has to work harder to produce more insulin, which can lead to fetal overgrowth, a condition known as macrosomia.
In people with diabetes, the negative feedback loop that normally regulates blood glucose levels is disrupted because they either do not produce enough functional insulin or their bodies do not use the insulin effectively. As a result, insulin cannot fulfill its role in lowering blood sugar after meals, which can be mitigated by insulin injections that allow transport and storage of glucose to decrease blood glucose levels.