Embryological Origin of the Uterus
The uterus develops from the fusion of the paired Müllerian (paramesonephric) ducts, making option B (Müllerian ducts fusion) the correct answer. 1, 2
Embryological Development
The Müllerian ducts form around the 10th week of fetal life and fuse in the midline to create the uterus, upper vagina, and fallopian tubes. 1
The fusion process begins caudally and progresses cranially, with the two paramesonephric ducts merging to form a single uterovaginal canal. 2
The Wolffian (mesonephric) ducts regress in female embryos under the influence of the absence of testosterone and anti-Müllerian hormone, so options involving Wolffian ducts (C, D, E) are incorrect. 2
Option A is incorrect because the Müllerian ducts do not degenerate in females—they actively fuse and differentiate to form the reproductive tract structures. 1, 2
Clinical Relevance to Müllerian Anomalies
When Müllerian duct fusion fails to occur properly, various uterine anomalies result, including unicornuate uterus (failure of one duct to develop), bicornuate uterus (incomplete fusion), and uterus didelphys (complete failure of fusion with two separate uteri and cervices). 3, 4
These anomalies account for 2.4% to 13% of all congenital reproductive tract abnormalities and can impact fertility and pregnancy outcomes. 4, 5
MRI is the gold standard for diagnosing Müllerian duct anomalies with 100% accuracy, while 3D transvaginal ultrasound provides 92% accuracy. 3
Fetal Development at 32 Weeks
At 32 weeks gestation, the fetus is in the third trimester with well-developed organ systems and is approaching viability for extrauterine survival. 6
Serial ultrasound evaluation at this gestational age focuses on fetal growth parameters, amniotic fluid volume, and placental function. 6
Doppler velocimetry of the umbilical artery and middle cerebral artery may be performed if fetal growth restriction is suspected, as management incorporating umbilical artery Doppler is associated with improved perinatal outcomes and reduced odds of perinatal death by 38%. 6
The maternal uterus undergoes significant physiological changes by 32 weeks, with cardiac output increased by 30-50% and uteroplacental blood flow reaching up to 1000 mL/min (20% of maternal cardiac output). 6