Physiology of Pregnancy

Question 1

What is the pattern of contractions of the uterus during birth?

Answer 1

Rhythmic uterine contractions

Question 2

What are some physical signs of pregnancy?

Answer 2

Cessation of menstruation

Morning sickness

Increased frequency of urination

Increased size of breasts

Fatigue

Darkening of areolae

Question 2

What produces the amniotic fluid?

Answer 2

Foetal kidneys

Question 4

How many weeks duration is a normal pregnancy, from the last menstrual period?

Answer 4

40

Question 4

Explain the initiation of parturition?

Answer 4

CRH, the fetus and placenta contribute to the trigger

The cervix is stretched

Oxytocin is release from post pituitary, which trigger prostaglandin release > Uterine constractions begin

Positive feedback occurs

Question 4

Apart from milk ejection, what else does suckling stimulate?

Answer 4

The production of more milk for the next feed

Question 6

What hormone is used for the identification of pregnancy? In what samples can it be detected?

Answer 6

Human chorionic gonadotropin (hCG)

Blood and urine

Question 7

Why does suckling inhibit GnRH and the ovarian cycle?

Answer 7

You need to devote all the mother’s energy to the current child > once the baby sleeps through the night GnRH can return

Question 8

Why do maternal blood vessels get destroyed and blood drain into blood lakes in the placenta?

Answer 8

To prevent vasoconstrictors restricting blood flow

Question 9

In which period of pregnancy is morning sickness most common?

Answer 9

The first trimester

Question 10

Which hormone control mammary gland development during pregnancy?

Answer 10

Estrogen, growth hormone and cortisol stimulate gland development

Progesterone stimuates conversion of ducts to secretory epithelium in late pregnancy

Question 11

High sex steroid levels do what to milk production?

Answer 11

Suppress milk production

Question 13

Describe the interface between maternal and foetal blood

Answer 13

Maternal blood bathes embryonic blood vessels contained within chorionic villi

O2 crosses the chorionic membrane into embryonic vessels

Question 14

By how much does the cervix dilate during birth?

Answer 14

10cm

Question 15

When can you tell if twins will be monozygotic or dizygotic by ultrasound?

Answer 15

When monozygotic twins implant at the same place and share embryonic sacs

(Dizygotic twins don’t do this)

Question 16

At the end of which week will a pregnant mother miss her second period?

Answer 16

The 6th

Question 17

When do you get dizygotic twins?

Answer 17

When 2 oocytes are ovulated and fertilised by 2 separate sperm

Question 18

Which vessels returns embryonic blood to the placenta?

Answer 18

The umbilical artery

Question 19

Why does a baby coming out feet first sometimes require a cesarian?

Answer 19

Because there is less pressure on the cervix compared to when the head is coming first

Question 20

What are the names of the fetal membranes?

Answer 20

The inner amnion

The outer chorion