Lecture 3 - Prenatal Development and Birth

Conception

______________ - the process of a sperm fertilizing an egg, which can lead to pregnancy

• Happens during the fertile window— ovulation matters

• Day 1 pregnancy = day 1 of last menstrual cycle

Fertile window

___________________ - five days before ovulation, day of ovulation, and day after ovulation

Ovulation

____________ - the window where pregnancy usually happens/when the sperm fertilizes the egg– where pregnancy starts

• Typically occurs 14 days before the start of menstrual cycle

Multiple births

________________ - 3% of pregnancies… are increasing because more women OVER 35 giving birth

• Fraternal twins

• Identical twins

Women over 35 are more likely to have multiple births– a guess is because they are more likely to go through ovulation stimulation surges

Fraternal twins

_______________ - typical siblings born at the same time

• No different than a younger and older sibling

• Twin studies are very useful for disentangling nature vs. nurture

Identical twins

_____________ - one zygote that splits → identical genes

• Twin studies are very useful for disentangling nature vs. nurture

Implantation

Pregnancy begins at ____________.

“Weeks into pregnancy” = weeks since ______________.

Last day of menstrual cycle

“Weeks pregnant” = _______________.

Pregnancy

___________ begins at implantation.

• 40 weeks is when birth happens

hCG

The Mother’s POV → Relevant hormones

Human chorionic gonadotropin (_____) - “The Pregnancy Hormone”

• What pregnancy tests pick up

• Means you’re pregnant (assuming it is not a tumour)

Progesterone

The Mother’s POV → Relevant hormones

_______________- Prepares endometrium each menstrual cycle for pregnancy. Standard hormone in menstrual cycle, but shifts in pregnancy.

• No conception → Drops = period

• Conception → Rise = pregnancy

Estrogen

The Mother’s POV → Relevant hormones

______________ - Thins cervical mucus to improve sperm access

• Drops → period

• Rise → pregnancy

Relaxin

The Mother’s POV → Relevant hormones

________________ - Prepares endometrium each menstrual cycle

• Drops → period

• Rise → pregnancy

1st trimester

________________ - Symptoms have a purpose in increasing the viability of the pregnancy, or a byproduct of adaptive purposes

• Morning sickness– a better term is “All-day sickness”

• Breast changes – areolas also get darker so the child can see better

2nd trimester

_____________- Recommend for mother to gain 1-2 pounds per week

3rd trimester

___________________ - *Urination from a diff. cause than the ____ trimester diff from hCG

Cephalocaudal pattern

Fetal development

___________ - Development proceeds from the head downward

Proximodistal pattern

Fetal development

_______________ - Development happens from the centre ofthe body outward

Germinal Stage

____________ - Conception → Implantation

1st stage

• Zygote – Single cell containing full set of chromosomes (egg + sperm)

• Blastocyte – Hollow, fluid-filled ball. Buries into uterinewall

  • Some cells combine with uterine lining and begin constructing the placenta

Embryonic stage

_______________ - Implantation → End of week 8.

2nd stage

• All organs begin to develop, including the neural tube

• Week 5: Embryo is 10,000x largerthan zygote

• Week 6-8:Heart starts beating • Week 7: Spontaneous movement

Fetal stage

______________ - Week 9 → Birth

3rd stage

• Change in size of 2g → 7lbs

• Refinement of organ systems, particularly the brain and lungs

• Viability increases from 38% to 45% from week 22 to week 23, and 58% to 87% by end of week 24

• Week 14: Risk of miscarriage drops significantly

• YT vid for this

Prenatal behaviour

____________ - Fetuses can recognize their parents’ voices, but prefer their mother’s

• Activity level is stable overtime – active fetuses tend to become active children

• Fetuses who are less active but more reactive to maternal stimulation tend to become more fearfuland shy children

Mozart Effect

___________ - Idea that listening to Mozart will increase baby’s IQ → maybe?????/??

• Study of college students reported as babies overtime

• Prenatal stimulation associated with better outcomes on neonatal behaviour tests

• Fetuses will respond with movement to music they recognize

Genetic disorders

______________ - Genes have two alleles that are either dominant or recessive

• Child will inherit one allele from each parent

There are dominant and recessive genes, parents pass them on. If they get even just one dominant gene, the will have it in their phenotype. But, they can still carry a gene if they are recessive

Autosomal disorders

________________ - Caused by genes located on non-sex chromosomes

• Dominant disorders and recessive disorders

Recessive disorders

Autosomal disorders

_______________ - Both parents must be a carrier— 25% chance of child developing

• Child can still be a carrier if not

  • Examples: Albinism, Cystic Fibrosis

Dominant disorders

Autosomal disorders

_______________ - Only one parent must be a carrier— 50% chance of child developing if one parent, 75% chance if both parents carry it

• Cannot be a carrier if not

  • Examples: Huntington’s disease, schizophrenia

Sex-linked recessive disorders

Autosomal disorders → recessive disorders

_______________ - Found on the X chromosome

• Females unlikely to develop; more likely to be a carrier

• Fathers cannot pass to their sons as fathers pass on the Y chromosome when child is male

• Examples: hemophilia,red-green colour blindness

If a male has asex-linkedd disorder, you know it comes from the mother’s side

Chromosomal errors

____________ - Too many chromosomes

• Trisonomy: Condition where child has three copies of a specific autosome

  • Can involve autosomes or sex chromosomes

Chromosomal anomaly

______________ - Too few chromosomes

• Examples: Turner Syndrome, Cridu-Chat Syndrome

Teratogens

________________ - Outside agents that cause damage to embryo or fetus

• Most vulnerable during first eight weeks of gestation

• Transmission can occur via the bloodstream, vaginal canal, or breastmilk depending on the teratogen

Drugs

Teratogens

__________ - including some prescription drugs, can be teratogenic

• Risk-benefits ratio → risks should not outweigh benefits

Tobacco

Teratogens

______________ - Lower birth weight, neurobehavioural disorders (autism and adhd), risk of miscarriage, stillbirth, and neonatal death AND neonatal nicotine withdrawal

Alcohol

Teratogens

___________ - Can adversely affect ovum prior to fertilization

• Fetal Alcohol Syndrome (FAS): group of conditions with Fetal Alcohol Spectrum Disorder (FASD) being the most severe

Parental influence

Teratogens

_____________ - On average,fathers pass on 55 genetic mutations vs. 14 passed on by mothers. Sperm conditions contribute to infertility, decreased fertility, and miscarriage

• Toxins in seminal fluids or through environmental transmission

• Sperm count

• Male teratogenic risk

• Preconceptual factors

Location + practitioner

Birth choices

____________ - Depend on tradition and resources

• Canada: 97.8% of births occur at hospitals

• Home birth okay for uncomplicated pregnancies

• Practitioners:

  • Family doctor

  • Obstetrician-gynecologist (OBGYN)

  • Midwife

Pain management

Birth choices

• Analgesics → medications that relieve pain

• Sedative C tranquillizers → reduce anxiety

• Anesthesia (general or local)

  • Epidural

• Natural childbirth

  • Lamaze method

Analgesics

Birth choices → pain management

__________ - meds that relieve pain

• Opioids

• Nitrous oxide

Epidural

Birth choices → pain management → anesthesia

________________ - blocks pain from the lower part of the body

• Cons: impedes power to push, can slow birthing process which can increase chance for some complications and delay mother- baby contact

• Pros: Allows for restc,relaxation, and alertness; supports a more positive birth experience; and may reduce the risk for postpartum depression (more pleasant birth experience)

Lamaze method

Birth choices → pain management → natural childbirth

_____________ - promotes relaxation; and aims to reduce pain, distract, and build confidence; involves support person

Stage 1 Labour

_________________ - Three phases

Latent phase:

• Longest

• 1cm – 3-4cm dilation

• Contractions are far apart and not too uncomfortable

Active phase:

• Second longest

• 3-4cm – 8cm dilated

• Contractions are closer together and more intense

Transition phase:

• 8cm – 10cm dilated

• Contractions are closely spaced and strong

• Most painful

• Shortest phase (thankfully!)

Stage 2 Labour

___________ - Actual delivery, begins when mother starts pushing

• Typically lasts less than an hour

Stage 3 Labour

_________________ - Referred to as “afterbirth”.

• Delivery of the placenta C other material from the uterus

Lithotomy position

______________ - The most popular position but there’s lots of issues with it as its not in the mother’s best interest or the baby’s interest

• Standard because gives doctor good access

• Cons

  • Increases maternal pain and prolongs labour

  • Narrows birth canal

  • Increases risk of perineal tearing and sphincter injury

  • Increases need for episiotomy, Caesarian section, and forceps

  • Increases risks to baby from prolonged labour and higher chances of respiratory and heartrate issues

C-sections

_______________ - Typically used when babies are in breech (bottom/feet first instead of head first)

• Significantly lower risk of infant mortality or complications when occurs before labour onset

• Other reasons: fetal distress, failure for labour to progress in reasonable time, fetus is too large, maternal health conditions that could be aggravated by vaginal delivery or that pose danger to the fetus (e.g., certain teratogens)

• Some women choose elective C-sections

• Medically unnecessary C-sections are controversial

  • Risks of complications (e.g., uterine scarring, blood loss, postpartum infections)

  • Healthcare costs

  • Structural sexism?