Prenatal development and Birth Flashcards
what is the zygote/germinal stage?
Zygote or Germinal Stage (0-2 wks): Conception to implantation
What is the embryo stage?
Embryo (3-8 wks)
Structural Development
• Neural tube: Becomes brain & spinal cord
• Amniotic sac: Fluid-filled membrane protecting embryo
• Placenta: Disc-like structure connecting embryo to uterus
• Umbilical cord: Tube connecting embryo to placenta • Provides oxygen & nutrients • Removes carbon dioxide & waste
• Miscarriage risk highest
Can look around and feel- feet and mouths
What si the Foetus stage?
Foetus (9-38 weeks): functional development
Brain development and CNS development- connections strengthen- cerebral cortex develops a lot through this
Responds to stimulation
Wk 12: can tell sex
Reflexes develop
Wk 17-20 mother feeels movement
Wk 22-26: viability – if the baby was born prematurely it would probably be able to survive.
Last few weeks baby turns around so it’s born headfirst rather than feet first.
WHat is a teratogen?
Teratogen: An environmental agent that causes prenatal damage
9/10 births are normal
Effects during critical/sensitive periods
• Effects are specific
• Longer exposure is worse
• Some First 2 weeks- Zygote usually isn’t susceptible to teratogens as it’s not connected to mother yet.
EMbryonic stages 3-8: major structure abnormalities caused by teratogens
e.g. heart, eye, CNS, ears, genitals have no effect on mother
• Maternal/foetal genes may counteract effect
What is Thalomide?
Drug for morning sickness (1957-61)
• Caused structural abnormalities in limbs & face
Must have taken through week 4-5
Majority exposed didn’t get symptoms.
What is DES?
Hormone to prevent miscarriage (1947-64)
• Linked to reproductive problems & cancers in offspring
Give some legal teratogens?
Caffeine:
Miscarriage
Low birth weight e.g. 200mg
Tobacco Chemicals in smoke Miscarriage and prematurity Nicotine affects placenta --> poor nutrition --> low birth weight Role of oxygen ADHD Carbon monoxide- displaces Oxygen so foetus gets less oxygen Mother should give up a month before Passive smoking also effects it.
Alcohol:
Passes right through placenta into foetus
What can some teratogens lead to?
Foetal Alcohol Syndrome (FAS):
Stunted growth, physical defects, often mental retardation
Foetal Alcohol Spectrum Disorder (FASD)
• Role of oxygen
• Last trimester worst (unlike most teratrogens- affects brain development as this is period of time where it’s developing rather than structure)
• 1-5% affected in UK
give some environmental toxins
Radiation (atomic bomb, nuclear reactor meltodowns)
-Miscarriages, stunded growth, physical defects, cancer
Pollution (lead, murcurary e.g. in tuna, PCBS) - PRematurity, LBW or cognitive impairments.
Air pollution particles found in mothers placenta…
Outline how infectious diseases can be an example of a tetarogen
Infectious diseases
serious (TORCH) •
Toxoplasmosis: Parasitic infection in cats & raw meat
brain & eye damage
• Other viruses (e.g., HIV/ AIDS
Mortality, small head, physical & mental defects)
25% mother untreated
1% if mother is treated
• Rubella: Virus damages eyes, ears, heart; causes mental retardation
20,000 babies effected with heart issues
• CMV: Virus w/ mild (or no) flu-like symptoms- visual,hearing difficulties, mental retardation…
• Herpes: Sexually transmitted virus; damages eyes, brain, motor system
give some other diseases not included in TORCH that affects pre-natal development
Chlamydia- issues with fertility
Syphilis passed on
Zika Virus
• Mosquito-borne infection; Identified in Uganda (1947)
• 2016 epidemic: Asia, South America
• Can cause mild fever in mother
• Causal link to infant microcephaly (small brain) confirmed Sep 2016
• Infects foetal brain tissue
• No vaccine (yet)
• Lifelong sensory, motor & cognitive disability
Outline maternal risk factors that can affect development
Age
• Fertility problems increase w/ age
• Miscarriage & chromosomal damage risks increase w/ age
• Teen mums also at risk- less likely to have prenatal care…more detail needed
Old mums- who have had a child- lower risk of defects
Nutrition
• Weight gain
• Affected by ethnicity and SES
•(needed) Folic acid or: Neural tube defects
If neural tube doesn’t close at end so not enough pholic acid- Anencephaly
If the neural tube doesn’t close at the lower end the spinal cord sticks out- spina Bifida
Prenatal Care
• Health
• Toxaemia/Pre-eclampsia: Pregnancy-caused high blood pressure
Restricted growth, preterm birth, stillbirth
• (Gestational) Diabetes-
High birth weight, preterm birth, temporary breathing problems
Outline what is meant by the APGAR scoring system Outl
activity, Pulse, Grimace(reflex irritability) Appearance(skin colour) (reparations) 1minute after baby is born and then 5 minutes after baby is born
10 is baby Is perfect condition 1 is baby is in need of urgent care.`
Outline the risks with preterm babies
Preterm: < 36 wks • < 10% births (UK) • Avg weight 2.3 kg (5 lb) • Risk of cognitive delay • Appropriate weight for pregnancy length • Very preterm: < 32 wks
• Extremely preterm: < 26 wks
• Inadequate surfactant (liquid in lungs that sends O2 into blood)
• May cause respiratory distress syndrome
• Risk Factors – only evident in half of cases
Hard to predict what causes preterm births
Something like half of babies pre-term births for no apparent reason.
Outline the risks of small-for date- babies (LBW)
Full-term OR preterm
• BELOW expected weight for pregnancy length
• ‘Normal’ birth weight is approx. 3.5 kg (7.7 lb)
Low Birth Weight (LBW) < 2.5 kg (5.5 lb) Very Low Birth Weight (VLBW) < 1.5 kg (3.3 lb) Extremely Low Birth Weight (ELBW) < 1.0 kg (2.2 lb)
Issues with placenta- infections
Links with learning diificulites, mental difficulties, poor social skills, issues in school
