Physiology of Pregnancy

Question 1

What are 3 periods of development in pregnancy and what weeks of gestation do these correspond to?

Answer 1

Early pregnancy (weeks 1-2)
Embryonic period (weeks 3-8)
Fetal period (weeks 9-38)

Question 2

Is the dividing zygote (weeks 1-2 of pregnancy) susceptible to teratogens?

Answer 2

No

Question 3

In what period of development does most of organogenesis take place?

Answer 3

Embryonic (weeks 3-8)

Question 4

What is the duration of human pregnancy as measured from last menstrual period and as measured from fertilisation? If last menstrual period or date of ovulation is not known, how can the foetal age be estimated?

Answer 4

280 days (40 weeks) from last menstrual period
266 days (38 weeks) from fertilisation
Foetal age can be estimated by length and other ultrasound measurements of foetus

Question 5

List 6 early physical signs of pregnancy

Answer 5

Cessation of menstruation
Morning sickness
Increased frequency of urination (due to pressure on bladder or influence of progesterone)
Increased size of breasts
Fatigue (progresses with pregnancy)
Darkening of areolae

Question 6

What part of the dividing zygote forms the placenta?

Answer 6

The trophoblasts invade the maternal endometrium and form the placenta

Question 7

What is the composition and role of the amniotic fluid?

Answer 7

Mostly foetal urine

Acts as a buffer to support foetal movement and growth