30-year-old G3P2 patient visits an antenatal clinic at 20 weeks. She reveals during history that her first baby was 4.6 kg delivered by cesarean section, second baby was 4-8 kg delivered by c/section. Gynecologists suspect gestational diabetes and orders a GCT. The blood sugar levels after 50 gms of oral glucose are 206 mg/dl and the patient is thus confirmed as a case of gestational diabetes. All of the following are known complications of this condition except:

**Core Concept**
Gestational diabetes mellitus (GDM) is a condition characterized by high blood glucose levels first recognized during pregnancy. It is associated with various maternal and fetal complications due to insulin resistance and hyperglycemia.

**Why the Correct Answer is Right**
The primary pathophysiological mechanism underlying GDM is insulin resistance, which leads to hyperglycemia. This condition is exacerbated by the placental hormones, particularly human placental lactogen (HPL), which promotes insulin resistance. The resultant hyperglycemia can lead to various complications, including fetal macrosomia, preterm labor, and an increased risk of cesarean delivery.

**Why Each Wrong Option is Incorrect**
* **Option A:** Fetal macrosomia is a known complication of GDM, characterized by excessive fetal growth due to the transfer of glucose from the mother to the fetus.
* **Option B:** Preterm labor is a recognized complication of GDM, as the hyperglycemia and insulin resistance can lead to premature activation of the fetal hypothalamic-pituitary-adrenal axis.
* **Option D:** Preeclampsia is a known complication of GDM, as the placental hypoxia and endothelial dysfunction can lead to the development of preeclampsia.

**Clinical Pearl / High-Yield Fact**
It is essential to diagnose GDM promptly, as early intervention with lifestyle modifications or insulin therapy can significantly reduce the risk of complications.

**Correct Answer:** A.

✓ Correct Answer: C. Congenital malformations in fetus