Normal Placenta and Umbilical cord

What is the appearance of the umbilical cord?

The umbilical arteries are longer than the vein and twisted around the vein, giving the cord a 'braided' appearance.

What is the primary function of the umbilical cord?

To transport blood between the fetus and the fetal portion of the placenta.

When does the umbilical cord form during gestation?

During the first 5 weeks of gestation.

What happens to the gut during embryonic development related to the umbilical cord?

Gut herniation occurs into the proximal cord between 7 and 10 weeks; it returns by 10-12 weeks.

What is the average length of the umbilical cord?

50-60 cm.

What is the average diameter of the umbilical cord?

3.8 cm.

What is the structure of the placenta?

A discoid organ weighing 480-600 gm at delivery, usually 2-4 cm in AP dimension.

What are the two surfaces of the placenta?

The maternal surface is irregular and divided into cotyledons, while the fetal surface is smooth and covered by chorionic and amniotic membranes.

What hormones does the placenta secrete?

Progesterone, human chorionic gonadotropin, and converts fetal steroids to estrogen.

What can reduce maternal placenta circulation?

Conditions that decrease uterine blood flow, such as hypotension, renal disease, or smoking.

What is placental grading?

A method to assess gestational age based on structural changes in the placenta as it ages.

What does a Grade 0 placenta indicate?

No calcifications and a smooth chorionic surface, typically up to 30 weeks.

What is the retroplacental complex (RPC)?

Composed of decidua basalis and portions of myometrium, including maternal veins draining the placenta.

What is the significance of identifying a Grade III placenta in early pregnancy?

It may indicate placental insufficiency, especially in the presence of maternal medical complications.

What percentage of term placentas are typically Grade III?

Only about 10%-15% of term placentas.

What is the average weight of the placenta at delivery?

480-600 grams.

What is the appearance of the umbilical cord in the first trimester?

Described as a 'stack of coins'.

What is the weight range of a normal placenta at delivery?

480-600 grams.

What is the typical dimension of the placenta in the anterior-posterior (AP) direction?

2-4 cm.

What is the maternal surface of the placenta like?

Irregular and divided into cotyledons by septae.

What is the fetal surface of the placenta covered by?

Chorionic and amniotic membranes.

What is the role of intervillous spaces in the placenta?

They serve as the site of exchange of oxygen, nutrients, and wastes between the fetus and mother.

What can reduce maternal placental circulation?

Conditions that decrease uterine blood flow, such as hypotension, renal disease, and smoking.

What does placental grading assess?

It assesses structural changes within the placenta as it ages and correlates with gestational age.

What indicates placental insufficiency in grading?

Identification of a Grade III placenta in the second or early third trimester.

What are the characteristics of a Grade 0 placenta?

No calcifications and a smooth chorionic surface, typically up to 30 weeks.

What defines a Grade 1 placenta?

Scattered calcifications and slight contouring of the chorionic surface, typically between 31-36 weeks.

What is a Grade 2 placenta characterized by?

Basal layer calcifications, typically between 36-38 weeks.

What features define a Grade 3 placenta?

Basal calcifications, interlobar septal calcifications, and infarcts, typically 38+ weeks.

What is the sonographic appearance of the retroplacental complex?

A hypoechoic area 1-2 cm deep to the placenta with possible venous channels.