Week 3: Prenatal development

Prenatal development

__________- when a miscarriage happens, something went wrong in these periods

1. Period of the Zygote (0 to ~2wks): Travel time (1wk)- zygote needs to get to uterine wall to implant.

2. Period of the Embryo (~3 to 8wks): Busy time-- major internal and external structures are formed Period of extremely rapid change-- embryo is very large compared to the zygote.

3. Period of the fetus (~9 to ~38wks): a period of growth, but not as rapid, as growth slows down dramatically. Brain development happens a lot here.

1) Period of the Zygote (0 to ~2wks)

Prenatal development

__________ -  Travel time (1wk)- zygote needs to get to uterine wall to implant.

2) Period of the Embryo (~3wks-8wks)

Prenatal development

__________ - Busy time-- major internal and external structures are formed Period of extremely rapid change-- embryo is very large compared to the zygote.

3) Period of the Fetus (~9wks to ~38wks)

Prenatal development

__________ - a period of growth, but not as rapid, as growth slows down dramatically. Brain development happens a lot here.

Teratogen

_________ - Non-genetic agents (environment) that can cause malformations in the embryo and fetus

• General ones

• Specific ones

General teratogens

Teratogens

___________ - includes…

• Age

  • Down syndrome

  • Achondroplasia (dwarfism)

  • Premature/underweight babies

• Nutrition:

  • Malnutrition

  • Overweight/obese mothers

  • Overweight/obese fathers

  • Diet

• Stress:

Age

Teratogens (general)

_________ - includes…

1. Down syndrome- common in older parents (both parents)

2. Achondroplasia (dwarfism) - older fathers

3. Premature/underweight babies: young mothers don't have enough resources to pass onto their babies, as the young mothers aren't done developing themselves.

Nutrition

Teratogens (general)

_________ - includes…

1. Malnutrition: as a mother, less resources to give to child

2. Overweight/obese mothers: harder to conceive, babies are bigger, heart disease higher

3. Overweight/obese fathers: lower sperm counts/sperm spins in circles

4. Diet: what ur actually eating in pregnancy, higher fruit gives a higher advantage in the child's memory and learning capacity

Stress

Teratogens (general)

_________ - Intense, prolonged anxiety + Depression—decreases rate of growth of the fetus, associated w/ low birth weight, prematurity and miscarriage

• Epigenetic change: Yehuda et. Al (2014)-- -- Holocaust survivors have lower cortisol, which is used to help deal with trauma, and lower amounts mean more stress is harder to deal with. BUT the enzyme that breaks down cortisol is lower, so cortisol stay longer.

• Intense anxiety means you can get a overactive baby

• Depression: higher premature birth rates (+fathers)

Yehuda et Al (2014)

Teratogens (general) - stress

______ - Holocaust survivors have lower cortisol, which is used to help deal with trauma, and lower amounts mean more stress is harder to deal with. BUT the enzyme that breaks down cortisol is lower, so cortisol stay longer.

Specific teratogens

Teratogens

__________ - includes…

1. Disease

2. Drugs

3. Rh Incompatibility: Rh is on the blood type, being positive or negative. Most are positive—incompatible blood can cause the mother’s antibodies to attack the baby during the second birth. You need to take something to prevent the antibodies

4. Radiation: Ultrasounds—shown to cause teratogens in mice. Left-handedness is an indicator of mild brain dmg sometimes, if exposed to more ultrasounds, higher likelihood to be born left-handed.

5. IVF?: one-sperm one egg technique-- double the rate of birth defects like cleft palate, heart problems, etc. This technique is cheaper compared to the similar technique to real conception

Disease

Teratogens (specific)

__________ - includes…

1. Herpes type 2

2. AIDS/HIV

3. Diabetes

4. Zika virus: microcephaly, can be passed on even by a partner during sex

5. Flu: may play a causal role in the development of fetal brain abnormalities and lead to problems such as autism and schizophrenia

Drugs

Teratogens (specific)

__________ - includes…

• Aspirin: harmful in very high, frequent amounts/long durations

• Caffeine

• Cigarettes

• Vitamin A: High does of A and D have been associated with central nervous system damage.

• Heroin/crack/methadone

Rh incompatibility

Teratogens (specific)

__________ - Rh is on the blood type, being positive or negative. Most are positive—incompatible blood can cause the mother’s antibodies to attack the baby during the second birth. You need to take something to prevent the antibodies

Radiation

Teratogens (specific)

__________ - Ultrasounds—shown to cause teratogens in mice. Left-handedness is an indicator of mild brain dmg sometimes, if exposed to more ultrasounds, higher likelihood to be born left-handed.

IVF? (one-sperm one-egg)

Teratogens (specific)

__________ - one-sperm one egg technique-- double the rate of birth defects like cleft palate, heart problems, etc. This technique is cheaper compared to the similar technique to real conception

Teratology

Teratogens

__________ -

Period of the embryo (weeks 2-5)

Teratogens

__________ - which period is most consequential?

• During this window, organogenesis (the formation of major body systems and internal organs) takes place. Exposure to harmful agents during these weeks most commonly results in major structural birth defects

• After: still vulnerable. Critical periods depend on the body part

Critical periods

Teratogens

Psychoteratology

Teratogens

__________ - Discovery/study of behavioural effects of teratogens

• Behavioural measures:

  • Activity level

  • Sleep rhythms

  • Problem solving

  • Rate of behavioural development

  • Learning ability

  • City vs. rural: City babies IQ lower than rural—hypotheses related to air pollution

  • Stress: Aspirin and tyenol

  •   Nicotine

  • C-section: Adler & Wong-Kee-You (2015) York

History of teratogens

Teratogens

__________ -

1. General beliefs: Embryo/fetus live in a privileged area, cushion and safe. Temp doesn't change, fetus is protected-- idea that placenta and belly were protected

2. 1930s: X-rays started being used more-- women started to have miscarriages, microencephaly- common thread was women getting x-rays

3. 1940s: measles- if a pregnant woman has measles, babies would be born with malformations of eyes, ears, heart and brain. Which is now why we vaccinate

4. 1960s: real wake up call was thalidomide-- was used for many conditions, and started be used for morning sickness. It's a sedative, but issue is saying it was ok on rabbit fetuses, and got approved, but on humans doesn't work the same. Canada was the last country to pull if off the shelf, so there's lots of babies with these malformations. Limbs often deformed or missing, impacts on eyes. Chronic pain also Canadian doctor who worked in the FDA refused so it wasn't used in the U.S

   1. Treats insomnia but many babies were born with stunted limbs. The extremities undergo rapid development during the 2nd trimester of pregnancy.

General beliefs

History of teratogens

__________ - Embryo/fetus live in a privileged area, cushion and safe. Temp doesn't change, fetus is protected-- idea that placenta and belly were protected

1930s: X-rays

History of teratogens

_________ - started being used more-- women started to have miscarriages, microencephaly- common thread was women getting x-rays

1940s: Measles

History of teratogens

_________ - if a pregnant woman has measles, babies would be born with malformations of eyes, ears, heart and brain. Which is now why we vaccinate

1960s: Thalidomide

History of teratogens

_________ - real wake up call was thalidomide-- was used for many conditions, and started be used for morning sickness. It's a sedative, but issue is saying it was on rabbit fetuses, and got approved, but on humans doesn't work the same. Canada was the last country to pull if off the shelf, so there's lots of babies with these malformations. Limbs often deformed or missing, impacts on eyes. Chronic pain also Canadian doctor who worked in the FDA refused so it wasn't used in the U.S.

• Treats insomnia but many babies were born with stunted limbs. The extremities undergo rapid development during the 2nd trimester of pregnancy.

Fetal alcohol spectrum disorder (FASD)

_________ - how does alcohol get fetus

1. Placenta

2. Metabolization - women don’t do it as quickly

3. Elimination

4. Role of the mother

Effects — alcohol can cause (physical + behavioural)

Commonality

Physical effects

FASD (effects of alcohol on fetus)

____________ -

1. Miscarriages stillbirths

2. Prenatal/postnatal growth - babies born are smaller/underweight facial differences

3. Seizures/epilepsy

Behavioural effects

FASD (effects of alcohol on fetus)

__________ -

1. Most common causes of intellectual disability is 85% FASD kids, IQ > 70

2. Attention deficits - easily distracted

Commonality

FASD

__________ -

• 9/1000 FASD babies/year

• 4% of Canadians - high number

• Top developmental disability.

25; 78; 691

FASD

__________ - how much alcohol?

• Need an alcoholic mother ___/1000 full FASD

• ___/1000 to ____/1000 pFAS

• Alcoholic women can still have kids who show no signs of babies with FASD

• More alcohol = more information-processing, reasoning, executive functioning, lower IQ, poorer school marks, poorer fine and gross motor coordination

  • But 25% of Canadian women report drinking during pregnancy

3; 1-2; binge

FASD

__________ - How little alcohol?

• __oz alcohol per day = FASD

• ___oz per day = lower birth weight 4 drinks/week = learning deficits

• binge-drinking = can cause no effects to causing death

Confounding factors?

FASD

__________ - A child solely being affected by alcohol could be confounding, there could be interactions of diff. teratogens affecting the fetus

• maternal health factors

• obstetric factors

•  paternal factors

• postnatal factors

• diagnosis difficulties