Prenatal Development and The Newborn

Chapter 3

Prenatal Development - Timeline

• average of 38 weeks (9.5 months) for fertilized egg to turn into a newborn human

• 22-28 weeks (5.5-7 months) — age of viability

  • fetus has working senses and will survive if born now

How can we test fetal hearing?

• monitor fetal heart rate

Kisilevsky et al. (2003): Fetal Hearing Study

• can fetuses remember and recognize their mother’s voice and differentiate between familiar and unfamiliar voices?

  • tested 60 fetuses (and their mothers) for 6-minute testing sessions

  • women came in to read poems

  • recordings were played for fetuses

• 2 groups

  • mother’s voice condition

  • stranger’s voice condition

• Measured heart rate before, during, and after voice recording

Fetal Hearing Study — Results

• mother’s voice group

  • heart rate increased more during recording compared to baseline

• stranger’s voice group

  • heart rate stayed pretty consistent, maybe even small decrease, during recording compared to baseline

• conclusion: fetus can differentiate mother voice and stranger voice

Fetal Taste

• food that the mother eats is transmitted to amniotic fluid which the fetus swallows

• suggestion that a baby prefers foods that they tasted in the womb or when being breastfed

Mennella et al. (2001): Fetal Taste Study

• do infants prefer food that their mother ate during pregnancy or breastfeeding?

  • tested 46 pregnant mothers (last trimester) who delivered healthy babies and breastfed them

• 3 groups

  • group CW

  • group WC

  • group WW

• Tested infants in all 3 groups for preference between carrot-flavored vs plain cereal

Fetal Taste Study — group CW

• mothers drank only carrot juice in the last trimester of pregnancy

• mothers drank only water in the first months of lactation

Fetal Taste Study - group WC

• mothers drank only water in the last trimester of pregnancy

• mothers drank only carrot juice n the first months of lactation

Fetal Taste Study - group WW

• mothers drank only water in the last trimester of pregnancy

• mothers drank only water in the first months of lactation

Fetal Taste Study - Results

• Based on 3 measures

  • negative faces - how many times infants made a negative facial expression while eating

  • mother’s perception - mother watched video and got them to say what they thought their child thought of the cereal

  • intake - how much did they consume

• calculated differences between reactions to both cereals

• all measures indicate that exposure to tastes during pregnancy or breastfeeding effects the child’s food presence

Influences on Prenatal Development

• Nutrition

• Stress

• Parental Age

• Teratogens

Nutrition

• the fetus relies on nutrients from the mother

• mothers often need to increase calories by 10-20% to support themselves and the growing baby

• need to eat enough food and good quality food

  • malnutrition during pregnancy may result in long-term developmental challenges

• recommend supplements (prenatal vitamins) for extra proteins, vitamins, minerals

  • e.g., folic acid (folate) important for development of nervous system, spinal cord, spine

Stress

• high levels of chronic stress is associated with poorer outcomes for your baby (stress here and there is ok)

• higher maternal stress during pregnancy → once baby is born they are harder to soothe, lower attention, problem behaviour

  • women stressed about their pregnancy tend to have underweight babies

• Why does this happen

  • genetics

  • environment (babies learn from their environment to be stressed)

  • stress can secrete hormones that effect oxygen reaching the fetus

• people who were pregnant and had connections to 9-11 had higher levels of cortisol and so did the babies

  • evidence of generational effects of trauma

Transgenerational Trauma - Epigenetics

• epigenetics

  • the continuous interplay between genes and our environment

• genes are modified and either turned on or turned off

• changes in gene expression found in trauma survivors

  • and their children who were not exposed to the trauma

    • e.g., 9-11 survivors, holocaust survivors, residential school survivors

Parental Age

• age of birth of first child has been increasing (average age in Canada is 29)

• as of 2012: women giving birth in their 30s has doubled from 1980

• age range of 20-30 is the best time for fertility and personal lives

  • highest fertility in 20s

  • more pregnancy complications after 35 years of age (decrease in fertility, increase in complications)

    • not a hard deadline, just harder after this age

Why are women having kids later?

• advancing reproductive technologies

  • NB: infertility treatment fund gives up to $5000 for NB residents with diagnosis of fertility problems

  • freezing eggs: you can have kids later with younger, healthier eggs (super expensive!!)

Teratogens

• an agent that causes abnormal prenatal development

  • diseases (e.g., HIV, AIDS, genital herpes, syphallis)

    • can directly attack baby through placenta or can be effected if they line the birth canal

  • certain drugs (e.g., aspirin, caffeine, alcohol, nicotine)

    • can reduce oxygen and nutrients to baby

    • fetal alcohol syndrome

  • second hand smoke

  • marijuana use can have effects similar to nicotine (less researched)

  • environmental hazards (e.g., contaminated water, lead, x-rays)

APGAR Score

• 5 vital signs of life - scored on a scale from 0-2

  • A-Activity: moves limbs actively

  • P-Pulse: at least 100 beats per minute

  • G-Grimace: reflex by crying from irritating stimulus (pinch baby)

  • A-Appearance: lack of blue-grey skin colour

  • R-Respiration: strong breathing and crying

• highest score is perfect 10

  • score of 7 or more = no worries

  • score between 4-6 = might be something wrong

  • score between 1-3 = serious, life threatening issue

Newborn Reflexes

• unlearned responses that are triggered by a specific stimulation

• indication of if the nervous system is working properly

• thought to help infants survive (evolutionary reason)

• 5 examples

  • palmar reflex

  • moro reflex

  • rooting reflex

  • sucking reflex

  • stepping reflex

• at some point in development we lose these reflexes and start to do these things voluntarily

Palmar Reflex

• if you place something in the palm of a baby’s hand they will automatically wrap their fingers around and hold on

Moro Reflex

• when you put a baby down and their head falls back or they feel like they’re falling they will reach their arms out to grab onto something

Rooting Reflex

• when you stroke a baby’s cheek they will turn to face stimulus and open mouth to feed

Sucking Reflex

• put something in their mouth and they will automatically start sucking

Stepping Reflex

if you lift a baby up and put their feet on the ground they will move their legs around like they’re walking

Sudden Unexpected Infant Death

• could be due to these reflexes starting to fade away too early before they have enough voluntary control to complete these actions

Newborn Sleep

• sleep 16-18 hours daily

• sleep in “nap cycles”

  • cycle between awake/asleep every 4ish hours

• gradual shift to more “night sleep”

Baby Blues

irritation, resentment (towards baby and maybe partner), and crying after having a baby

• stress of the new baby and bodily changes/recovery after childbirth

  • hormonal changes

• experienced for about 1-2 weeks

• some evidence that fathers can also experience this

Postpartum Depression

feelings of irritability, low self-worth, disturbed sleep, poor appetite, lack of interest

• more serious and lasts longer than baby blues

• lasts for months after giving birth

• less common but still about 10-15% of women report experiencing this

• may not reciprocate/provide emotional range desired by infant

Still Face Paradigm

• react normally with infant, using facial expressions and then stop showing any emotion and see how baby reacts (baby gets very stressed when mom stops interacting but returns to normal when mom responds again)

  • same effects in fathers

Greater Risk of Postpartum Depression if…

• you experienced depression before pregnancy

• coping with other life changes during pregnancy or early in newborn stage

  • e.g., recent death in the family, made a big move (new house)

• unplanned pregnancy (particularly an unwanted pregnancy

• lack of support from others during pregnancy and in early newborn stage

  *mothers should seek help and be taken seriously