Lecture 9: prenatal Flashcards
what are the most common substances used by pregnant women?
alcohol and tobacco
what is the most common psychoactive substance taken by pregnant women?
cannabis
what are risk factors for substance use during pregnncy?
- History of drug or alcohol related problems
- Family history of substance use (genetic and
environmental factors) - Frequent encounters with law enforcement
- Having a partner who abuses substances
- History of sexual abuse
- Poverty and homelessness
- Psychiatric illness (up to 60%)– anxiety,
depression, PTSD
what is the possible drug effect on the fetus if the substance is taken within 20 days after fertilization, 3-8 weeks after fertilization, and in the2nd/3rd trimester?
- within 20 days: all or nothing (death or no effect)
- 3-8 weeks: maybe no effect, miscarriage, birth defect, increase risk of childhood cancer
- 2nd/3rd trimester: changes in growth and function of normally formed organs and tissue, no birth defect
what is the placenta?
a temporary organ that develops during pregnancy that attaches to the wall of the uterus, where the umbilical cord arises from
what is the function of the placenta?
- Provide oxygen and nutrients
- Remove harmful waste product
- Produce hormones
- Pass immunity
how is the drug transferred to the baby?
via the placenta through the same path for oxygen and other nutrients
the ability of a drug to cross the placenta depends on what drug properties?
- MW (<500-1000 Da)
- lipid solubility
- ionization/charge
- protein binding
what placental properties affect the ability of a drug to cross the placenta?
- surface area
- thickness
- pH of fetal and maternal blood
- metabolism
- uteroplacental blood flow
- presence of transporters
- concentration gradient across the placenta
what are the two main mechanism of fetal harm via drugs?
- direct: to the fetus itself (i.e. the drug binds to fetus)
- indirect: via the placenta, the mother’s physiological response to the drug, poor nutritional health (i.e. drug affect mother, which affects fetus)
what are the mechanisms of tobacco fetal harm?
- Nicotine and CO2 increases, causing vasoconstriction of blood vessels and reduces oxygen levels to fetus.
- Nicotine increases other chemicals that cause deregulation in normal fetal development (ex: catecholamines, cytotrophblast).
what are some obstetrical outcomes with tobacco use?
- Spontaneous abortion
- placenta abruption
- Placenta Previa
- Premature rupture of membranes
- Uterine infections
what are some neonatal outcomes of tobacco use?
- low birth weight
- Fetal growth restriction
- Increased risk of SIDS
- Cleft Lip/Palate
- Stillbirth
- Premature births
what are some childhood outcomes of prenatal tobacco use?
- SIDS
- risk of asthma
- congenital heart defects
- diabetes
- cognition
effect of tobacco on breast milk
- nicotine readily absorbed, and can decrease supply
- may cause: reduced appetite, diarrhea/vomiting, sleep issues, SIDS, increase HR/respiratory illness
mechanism of alcohol fetal harm
- Damages cells by production of reactive oxygen species and oxygen radicals, which interact with DNA, protein, and lipids.
- Ethanol and its metabolite, acetaldehyde are responsible for the biological effects.
- Alcohol is metabolized by the liver but often the liver is underdeveloped in a fetus and it is unable to eliminate the alcohol. It is sent back to the mother as a waste product and therefore, there is increased exposure time until the waste is eliminated.
- Prolonged exposure to fetus causes teratogenic effects, especially in 1st trimester.
neonatal outcomes of alcohol use
- FAS
- withdrawal symptoms at birth
- fetal death
- decreased birth weight
obstetrical complication of alcohol use
- Intrauterine growth
restriction - Increased risk of stillbirth
- Increased risk of miscarriage
what is fetal alcohol syndrome and its symptoms?
physical:
- inadequate growth
- birth defects of the face (thin upper lip, flat midface, underdeveloped jaw)
- microcephaly (small head)
cognitive:
- intellectual disability
- abnormal behavioural development
- increase risk of ADHD/ SUDs
effect of alcohol on breastmilk
- can cause decrease blood intake/sleep issues
- need to wait until all alcohol metabolized before breastfeeding (newborns metabolize it half of our rate)
what are the reported reasons for the increase use of cannabis in pregnant women?
anxiety, insomnia, morning sickness
mechanism of cannabis fetal harm
- Cannabinoids cross the placenta due to high lipophilicity and distribute into the fetal brain
- CB1 and CB2 receptors are found as early as 14 weeks gestation- deregulation in the development of this intricate system might be associated with adverse outcomes.
- long half-life so, low fetal clearance and measurable 15 mins after in fetal brain
neonatal outcomes of cannabis use
- Neonatal morbidity and death
- Premature birth
- Smaller head circumference
-Neurobehavioural
outcomes: ex: ASP - Congenital abnormalities; only correlations exist
obstetrical complications of cannabis use
- premature delivery
- risk of miscarriage
- IUGR
- reduced blood flow to placenta
