**Question:** Reabsorption of uterine septum in a fetus occurs by how many weeks of gestation normally?

**Core Concept:** Uterine septum is a congenital anomaly where the uterus has a partition between the two uterine cavities. Reabsorption is the process by which this partition is eliminated during fetal development.

**Why the Correct Answer is Right:** In normal fetal development, the uterine septum typically resolves and disappears by the 24th week of gestation. This process is driven by the action of enzymes like collagenase, which degrade the extracellular matrix of the septum, allowing the septum to be resorbed by macrophages and other immune cells.

**Why Each Wrong Option is Incorrect:**

A. **Option A (20 weeks):** This answer is incorrect because, while the uterine septum may be partially absorbed by 20 weeks, complete resolution is not achieved until later in gestation.

B. **Option B (24 weeks):** Although the uterine septum undergoes resorption during the 24th week, this answer is not entirely accurate because the process continues after this week, ensuring complete resolution.

C. **Option C (28 weeks):** This answer is not correct because the uterine septum is typically reabsorbed by the 24th week, not the 28th week.

D. **Option D (32 weeks):** While the uterine septum may be partially absorbed by 32 weeks, the process is not complete until later in gestation, making this answer inaccurate.

**Clinical Pearl:** The reabsorption of the uterine septum is a crucial process for fetal wellbeing. A retained uterine septum can lead to complications like genitourinary malformations, such as renal agenesis, hydronephrosis, and oligohydramnios.

**Correct Answer:** Option D (32 weeks) is the correct answer because, although the uterine septum is typically reabsorbed by the 24th to 28th week of gestation, the process is not complete until around 32 weeks. This ensures that the fetus has adequate time for the uterine septum to be reabsorbed, leading to a healthy development of the urinary system and overall fetal wellbeing.