Pregnancy

Question 1

What stage in the pregnancy is the organogenesis stage (in days)?

Answer 1

17-60 days

Question 2

The transfer of drugs from the mother doesn’t really occur until what stage of the pregnancy?

Answer 2

The organogenesis stage, which is when the placenta is formed. The placenta is the main way drugs are transferred between mother and fetus.

Question 3

What size drugs (in daltons) diffuse quickly into the placenta?

Answer 3

< 500 daltons

Question 4

Drugs can have a prolonged exposure to fetuses due to what two reasons?

Answer 4

• drugs are weak bases (ionised)

drugs attach to embryonic proteins

Question 5

What size drugs (in daltons) diffuse slowly?

Answer 5

500-1000 daltons

Question 6

What are the only two things that can cause teratogenicity in the blastocyst stage of pregnancy?

Answer 6

Cytotoxic drugs and ethanol.

Question 7

Category B is considered to be more safe than category C, true or false?

Answer 7

False.

C indicates a drug that is yet to be fully researched in humans. B indicates a drug taken by a small number of women in a study, with varying subcategories (B1, B2, B3). But because category B is about small studies, it does not hold much evidential weight. Because of this, it is more accurate to assume the B and C are inconclusively better than one another.

Question 8

What size drugs (in daltons) don’t diffuse into the placenta?

Answer 8

> 1000 daltons

Question 9

True or false, category A pregnancy scheduling is better than category C.

Answer 9

True.

Category A indicates a drug tested in a large number of women with no effects found on the fetus.

Question 10

An altered gastric pH for pregnant women means what for drug administration?

Answer 10

It may alter the oral bioavailability of drugs.

Question 11

Distinguish between the pregnancy subcategories B1 and B3.

Answer 11

B1: Study on small amount of women, no effect on fetus + no effect on pregnant animals.

B3: Study on small amount of women, no effect on fetus + some results of teratogenicity in animals.

Question 12

What time frame in the pregnancy is the blastocyst stage?

Answer 12

0 to 16 days

Question 13

Distinguish between category D and category X pregnancy scheduling.

Answer 13

D: The drug causes or is suspected to cause increased malformations in fetus, but may be acceptable to use despite the risk (i.e. to Rx chronic diseases in the mother).

X: Contrainidicated in those who are pregnant and those who intend to become pregnant.

Question 14

The most potent teratogens are the ones that do or do not cause symptoms in the mother?

Answer 14

The teratogens that do not cause symptoms are the worst, because its effects will then go undetected until it has caused a significant amount of harm to the fetus.

Question 15

66% of drugs are found in which pregnancy category?

<1% of drugs are found in which pregnancy category?

Answer 15

66% = C: Unresearched in humans.
<1% = A: Researched on large cohort of pregnant women and found to be safe.

Question 16

Pregnant women experience an increase or decrease in albumin concentration during pregnancy?

Answer 16

Decrease.

It tends to go down to about 70-80%

Question 17

1. Thalidomide was considered safe originally because __________
2. Thalidomide has negative effects on which stage of pregnancy?
3. Thalidomide has a major effect on which developmental process?

Answer 17

1. It was tested on animals with no harmful results shown. After this, however, it became necessary to test on pregnant animals.
2. Organogenesis, particularly the neural tube development.
3. Angiogenesis, the formation of new blood vessels. This leads to the shortening or absence of limbs (phecomelia and amelia, respectively).

Question 18

Teratogens occurring during the 17-60 day window will affect what period of the pregnancy and will produce what types of abnormalities?

Answer 18

Gross malformations,
Organ effects, and
Structural effects.

Question 19

Smoking is considered a major teratogen, true or false?

Answer 19

False. Though there is uncertainty about this.

Question 20

A decrease in the fetal environment pH means that what type of drugs are going to accumulate?

Answer 20

Weak bases.

The acidic environment will donate protons to the weak bases, making the more ionised, meaning that they then cannot easily diffuse through lipid membranes – i.e. they become trapped.

Question 21

Smoking during pregnancy has three major effects, name them.

Answer 21

1. Decreased birth weight.
2. Increased chance of SIDS (x3)
3. Increased chance of obstetric and perinatal complications.

Question 22

True or false, the same teratogen always causes the same malformations on a fetus.

Answer 22

False. The same teratogen can cause different malformations if adminsitered at different times in the pregnancy.

Question 23

In Australia, is drinking during pregnancy common?

Answer 23

Yes, 80% of mothers drink alcohol during their pregnancy.

Question 24

Majority of birth defects do or do not have a causative, identifiable factor?

Answer 24

Majority of birth defect do not have an identifiable causative factor, approximately 70%

Question 25

Foetal alcohol syndrome occurs with what percentage of alcoholic mothers?

Answer 25

30%

Question 26

Describe the three categories of drugs mainly used by pregnant women.

Answer 26

1. Drugs used to relieve the symptoms of pregnancy – nausea, vomitting, pre-eclampsia.
2. Drugs used to treat chronic conditions – antiepileptics and diabetes medications.
3. Drugs used of abuse – alcohol and heroin.

Question 27

Name the four major characteristics of Foetal Alcohol Syndrome.

Answer 27

1. Elongated philtrum (part between the nose and mouth).
2. Widened space between eyes.
3. Thin upper-lip.
4. Behavioural abnormalities – poor social integration, hyperactivity.

Question 28

Pregnant women have an increased cardiac output. This leads to increased CL of drug. What are the two reasons for that?

Answer 28

Increased GFR and increased liver perfusion.

Question 29

Foetal alcohol syndrome is more important in:

(a) Sustained moderate blood alcohol content
(b) Higher peak ethanol concentration in histogenesis stage of pregnancy
(c) Higher peak concentration early in pregnancy
(d) It is undetermined and correlated with any alcohol consumption during pregnancy

Answer 29

(c) Higher peak concentration early in pregnancy

Question 30

Exposure of a drug is important for teratogenicity. But exposure has multiple elements. What are they?

Answer 30

Amount (mg)?
When in the pregnancy?
For how long was the fetus exposed?

Question 31

There is evidence that even 2 units per day of alcohol is harmful to pregnant mothers, true or false?

Answer 31

False.

There is no evidence that this has any effect. However, there is also no safe threshold.

Question 32

An increase in body fat in pregnant women means what for Vd?

Answer 32

In lipid soluble drugs the Vd will increase.

Question 33

Foetal Alcohol Syndrome is common in those who drink < 5 units per day, true or false?

Answer 33

False.

Question 34

What stage is the histogenesis stage of the pregnancy (in days)?

Answer 34

> 60 days

Question 35

What are the three stages of pregnancy (in chronological order)?

Answer 35

1. Blastocyst
2. Organogenesis
3. Histogenesis

Question 36

Teratogens occurring in the >60 day period of pregnancy will cause what types of malformations?

Answer 36

Functional maturation of the fetus – meaning the functionality of the organs themself.

Question 37

Drugs can have a prolonged exposure to fetuses due to what two reasons?

Answer 37

1. The drug is a weak base (or generally just ionised).

2. The drug binds to embryonic proteins.