Pregnancy

Question 1

what is Early development of the human embryo is vulnerable to

Answer 1

teratogens- factors that can affect the details of development.

Question 2

what complications can occur early

Answer 2

spina bifida and cleft palate occur in early stages of development.

Question 3

when is spontaneous loss of pregnancy most common

Answer 3

during the first trimester is very common and

around 1/3 of all conceptions do not complete the first trimester

Question 4

what is absolute limit of infant survival

Answer 4

the second trimester is the absolute limit of infant survival, without modern neonatal intensive care

22 weeks of pregnancy and 50% survival at about 25 weeks.

Question 5

how long is first trimester

Answer 5

0-13 weeks

Question 6

how long is second trimester

Answer 6

14-26

Question 7

what gestational age is limit of viability

Answer 7

23 weeks

Question 8

once limit of viability is passed what becomes a problem

Answer 8

early delivery (10%)

Question 9

what causes early delivery

Answer 9

labour starting before term

deteriorating maternal or fetal health- growth restricted infants

and pre-eclamptic pregnancies.

Question 10

define term time period

Answer 10

term covers 37-41 weeks of gestation

expected time of delivery is term (39-40 weeks)

Question 11

what infants are at most risk and why

Answer 11

Infants born before 32 weeks GA

due to incomplete development of their lungs, digestive system, brain and immune system.

Question 12

what are the main risks in the 3rd trimester

Answer 12

concerned with birth.

Risks associated with labour can be minimised by monitoring fetal health and

delivery by Caesarean section if that is indicated.

Question 13

what time period is the 3rd trimester

Answer 13

27-39 weeks

Question 14

what anatomical and physiological changes INCREASE in mother during pregnancy

Answer 14

weight
hormone levels
blood clotting tendency
basal body temp
breast size
nausea and vomiting
vaginal mucous production
ALL INCREASE

Question 15

WHAT decreases in mother

Answer 15

Decreased blood pressure

Question 16

what other functions and states off the body are altered in the mother

Answer 16

Altered brain function/ appetite/ fluid balance and

urinary frequency/ emotional state/ joints/ immune system

Question 17

what happens when the conceptus make contact with maternal tissue at week 4

Answer 17

As conceptus grows, it makes transient contact with maternal capillaries

rapidly proliferating cytotrophoblast cells form a shell around the conceptus

Question 18

what do cut-trophoblast cells do to the conceptus wk4

Answer 18

isolates conceptus from maternal blood

Question 19

what provides nutrients for the placenta and developing baby during first trimester

Answer 19

Decidual glands hypertrophy

Question 20

how long does the cytotrophoblast shell last

Answer 20

Cytotrophoblast shell remains in place till about 10 weeks gestation, blocking the spiral arteries.

Question 21

how do cytotrophoblast cells remodel the arteries

Answer 21

During weeks 10-12 gestation, the shell gradually breaks down

results in the spiral arteries providing maternal blood to the placenta

Question 22

what provides nutrients following breakdown of cytotrophoblast shell

Answer 22

spiral arteries are main supply of nutrients to the developing placenta and fetus

Question 23

give a specific cause of miscarriage in late first trimester

Answer 23

If the placenta is not fully anchored to the maternal decidua, the increase in pressure can detach the placenta leading to miscarriage

Question 24

Remodelling of spiral arteries by cytotrophoblast cells begin and end

Answer 24

begins: 1st trimester
ends: 16-18 weeks gestation

(nutrient provision throughout trimester 2/3 the. growth is high)

Question 25

why is spiral artery remodelling essential

Answer 25

it converts narrow arteries to wide-bore vessels that can transport large volumes of maternal blood- providing the quantities of nutrients needed

Question 26

name another distinguishing feature of the remodelled arteries

Answer 26

There is also a lack of smooth muscle

Question 27

list the main functions fo the placenta

Answer 27

Exchange of nutrients/waste between vascular systems Connection Seperation biosynthesis - syntheti. active Immunoregulation

Question 28

describe the immunoregulatory function of the placenta

Answer 28

Interactions between placenta and maternal tissue ensures there is no rejection of the conceptus during pregnancy

Question 29

how does the placenta connect and why is this vital

Answer 29

make strong connections with the underlying maternal decidua (uterine lining) to last for the 9 months of pregnancy. Anchorage is essential as the placenta is in contact with maternal arterial blood.

Question 30

describe how placenta develops during pregnancy

Answer 30

placenta develops from a simple layer of cells to a complex multifunctional tissue as pregnancy progresses.

Question 31

what is the primary subunit of the placenta

Answer 31

placental villus which provides a large surface area for exchange between the maternal and fetal vascular systems

Question 32

compare functions of the placenta and lungs

Answer 32

Placenta has a parallel function to the lungs for the fetus during pregnancy so the arterial system= de-oxygenated blood; venous system= oxygenated blood

Question 33

Maternal surface of placenta sub-divided into.....

Answer 33

cotyledons, each containing one or more villi.

Question 34

where does the placenta develop

Answer 34

in the underlying layer of the cytotrophoblast, adjacent to the embryo

Question 35

describe how the placenta develops

Answer 35

Cytotrophoblast proliferates into the syncytium following implantation; first the cytotrophoblast column is formed which then undergoes branching. This branching process continues throughout pregnancy.

Question 36

does the placental villus change throughout pregnancy

Answer 36

Overall structure of placental villus does not change throughout pregnancy but there are a few modifications

Question 37

give an example of one of these modifications

Answer 37

For example, at term, there are fewer cytotrophoblast present which maxims the efficacy of nutrient transfer into the fetal blood, enhancing fetal growth in later pregnancy. ( closer apposition between the syncytium and the placental capillaries)

Question 38

define still birth

Answer 38

Stillbirth= death of an infant within the uterus, so that it is delivered without any signs of life; delivery after viability limit (23 weeks); potentially viable infants

Question 39

what is still birth linked with

Answer 39

cases tend to be linked with labour, but some cases occur before delivery- complication of pregnancy

Question 40

when can still birth occur

Answer 40

It can occur at any gestational age, including term.

Question 41

define miscarriage

Answer 41

deliver before viability limit, non-viable infants

Question 42

how can infant be assessed with during development

Answer 42

Doppler ultrasound a decrease in, or lack of, foetal movement may indicate an increased risk of still birth