2-Medical interventions, medicolegal stuff and yah Flashcards
from when is gestational age calculated?
the first day of your last period
by the due date, the majority of people has ___ given birth spontaneously
NOT!!!
multiparous
HAS birthed before
gives birth faster
nulliparous
has NEVER birthed before
gives birth slower
due date
280 days (40 weeks) from the first day of the last menstrual period
10 lunar months
term pregnancy
between 37-42 weeks (“window”)
pre-term
before full 37 weeks of pregnancy
post-term
after 42 weeks of pregnancy
when is membrane sweeping offered?
commencing at 38 to 41 weeks
medical guideline
when is induction offered and why?
41+0 to 42+0 weeks
medical guidelines
done because present evidence reveals a decrease in perinatal mortality with induction
in practice, when is formal induction performed?
41 weeks + 3 days of preganancy if labour hasn’t started yet on its own
membrane sweeping
AKA “membrane stripping”, “stretch and sweep”
- rationale: presumed to cause the release of ENDOGENOUS PROSTAGLANDINS from the adjacent membranes and cervix
- invasive procedure
- risk because touching the baby’s head
prostaglandins
hormone-like lipid compounds that are known to play a partial role in the initiation of labour
related to membrane sweeping
do we actually know what causes labour?
nope
pros of membrane sweeping
- may decrease the length of pregnancy (1-4 days on average)
- may reduce the rate of formal medical induction…. BUT to avoid one formal, sweeping of membranes must be performed in 8 women
cons of membrane sweeping
- can be very painful (7 on a scale of 1 to 10)
- can cause BLEEDING or IRREGULAR contractions
- in 1/10 women leads to rupture of the amniotic sac (“water breaking”) which then leads to formal induction within 24 hours according to current medical guidelines
- sometimes done WITHOUT CONSENT, during a vaginal/cervical exam at the end of pregnancy
effectivity of routine sweeping
routine sweeping from 38 weeks of pregnancy onwards does not seem to produce clinically important benefits
most common methods for induction of labour
- artificial oxytocin (Pitocin), IV drip
- prostaglandins (and vaginal misoprostol)
- mechanical methods (balloon catheters, amniotomy, etc.)
artificial oxytocin
- type of induction of labour
- Pitocin, IV drip
- currently recommended and most commonly used method
- involves continuous oxytocin administration throughout labour and after delivery
- but… doesn’t always work
- causes stronger contractions!!
prostaglandins (and vaginal misoprostol)
- type of induction of labour
- gel in vaginal opening and cervix
- more effective than oxytocin in bringing about vaginal delivery within 24 hours
- but… more likely than oxytocin to cause UTERINE HYPERSTIMULATION
uterine hyperstimulation and why it can be dangerous
- uterus contracting TOO STRONGLY
- is dangerous for previous C-sections since it can cause the scar to OPEN UP
- prostaglandins can cause this
mechanical methods of induction of labour
- balloons catheters, amniotomy, etc.
- reduced uterine hyper stimulation compared to prostaglandins
- increased maternal and neonatal infectious compared to prostaglandins and artificial oxytocin
- more rare compared to the others
what is the rationale for performing induction after 41 weeks?
increased risk of STILLBIRTH compared to 40 weeks
there’s an increase of 30%
but… remember the BACKGROUND RISK: the probability of stillbirth in general
(you just need to know the general idea of this)
base rate
the general, UNCONDITIONED probability of something (prior probability)
base rate neglect
when present with specific info (conditional probabilities, specific risks) we tend to ignore the relevant general information (unconditioned probabilities, background risks)
The representativeness heuristic
The heuristic is based on automatic attribute substitution: representativeness = likelihood of occurrence
(i.e., more representative = more likely to occur)
- It can result in neglect of relevant base rates
- a prototype or mental model is activated by the representative individual or event
- alternative mental models are not activated or are suppressed
Representative outcomes that serve as prototypes of events during childbirth:
lack of modern medical intervention leads to a dead baby/mother
- modern medical interventions lead to a healthy baby being born to a healthy mother
The representativeness heuristic leads us to:
- overestimate the risk of not intervening
- underestimate the risk of intervening
Precautionary
Assumed unsafe until proven otherwise
Anti-cautionary
Assumed safe until proven otherwise
Prevalence of anti-cautionary principle
Not unique to obstetrics
- often applies to new medical technologies and interventions in medicine as a whole
Not unique to medicine
- often applies to new technologies in society as a whole
Within medicine, it is linked to medical reversals
Some medical reversals from modern obstetrics
- routine X-rays for pregnant women (found to cause cancer)
- Thalidomide for pregnancy nausea (found to cause severe birth defects)
- routine pubic area shaving (found to cause infection rather than prevent it)
- routine episiotomy (found to cause tearing rather than prevent it)
Childbirth circa 1960
- Heavy sedation
- Routine enema & shave prep
- “Sterile” environment
- “Prophylactic” forceps
- Routine episiotomy
- Delivery in operating room
- Litothomy position (supine, legs in stirrups)
augmentation of labour meaning
when labour has happened SPONTANEOUSLY… but you’re not dilating fast enough
benefits of not clamping the umbilical cord immediately?
- baby stays connected to the placenta
- continues to receive blood and oxygen
- enables the gradual transition to breathing bc your lungs are squished when you’re first born
Representativeness
the degree to which:
- an individual matches the prototype of a category/group
- an event matches the prototype of the kind of events a process tends to generate
when does the biggest transformation in the umbilical cord happen?
in the first few minutes right after the birth
Wharton’s Jelly
a gelatinous substance within the umbilical cord (also present in vitreous humor of the eyeball)
umbilical cord
- protects and insulates umbilical blood vessels
- Changes its structure with cooler temperature (compared to body)
- Provides a physiological clamping action, slowing the flow of blood
- Contains stem cells and may have yet unknown benefits
how can stem cells in the umbilical cord be used
- create adult stem cells including neural cells in rats (Mitchell et al., 2003)
- treat brain damage in mice effectively (Cheng et al., 2015)
Delayed cord clamping (1-3 minutes) vs immediate (<60 sec):
- increase in blood volume of the newborn (20-30%)
- increase in red cell volume (50%)
- higher birth weight (mean increase 101 grams)
- fewer infants iron deficient (at 3-6 months, 50% decrease)
Placental transfusion
Not passive or influenced by gravity: even when baby is held above placenta, transfusion still occurs
historically, what would midwives do regarding the umbilical cord?
Historically, midwives would wait until the cord stops pulsating until they do anything to it
Aristotle and Hippocrates wrote approvingly of midwives’ practice of waiting until the cord stops pulsating
when do the first records for immediate cord clamping date back to?
late 1600s (probably don’t need to know the date tbh)
early explanations for the practice of cord clamping
- to avoid blood loss from the baby before physiological closure of the umbilical vessels
- to “spare the bed linen” from being soiled by placental blood leaking from the cut end of the cord
but… ’[the] common method of tying and cutting the navel string in the instant the child is born… has nothing to plead in its favour but custom”
Erasmus Darwin opinion about early cord clamping
1800s!
“a very injurious thing”
left babies “much weaker than [they] ought to be”
use of chloroform during childbirth
- early 20th century interventions in childgirth
- general anesthesia with chloroform during childbirth (Stage 2)
- chloroform passed through the umbilical cord to the baby, with the potential to cause profound respiratory depression
- cord immediately clamped and cut to prevent the baby from receiving any more of the chloroform
cord clamping
1960s: Became “the standard of care” in obstetrics
Promoted as a tool to prevent postpartum hemorrhage
The standard of care
- a person practicing obstetrics is charged with the responsibility of practicing within the standard of care
- failing to do so may establish the basis of litigation
- defined as those acts performed by a reasonably prudent practitioner
- influenced by the Clinical Practice Guidelines issued by each country’s professional society (e.g., The Society of Obstetricians and Gynecologists of Canada)
active management of the third stage of labour
- as opposed to watching and waiting to see what happens… you do this REGARDLESS
- is an interventionist package of care
- described it as the “cornerstone” of obstetric and midwifery practice
- goal is to LIMIT POSTPARTUM HEMORRHAGE
triad of interventions during active management of the third stage of labour
- administration of a PROPHYLACTIC UTEROTONIC DRUG (Pitocin)
- induce contractility of the uterus
- make the placenta separate from he uterine wall quicker - early cord clamping and cutting
- controlled traction of the umbilical cord
- pulling on the cord while applying counter pressure to help deliver the placenta
- helps it come out sooner!!
- can cause postpartum hemorrhage…
- capillaries are likely to be fractured
statistic evidence on the triad of interventions during active management of the third stage of labour
- immediate cord clamping DOES NOT decrease postpartum hemorrhage rates
- cord traction may not be important
- giving uterotonic might be the only intervention in the active management of stage 3 that is associated with reduced hemorrhage but:
- the quality of the evidence is generally low
- more data/research are needed
effects of early cord cutting on baby
- can lead to iron deficiency anemia in babies
- in premature infants, can lead to intraventricular hemorrhage… Bleeding in brain!!
WHO, UK, and Canadian guidelines for umbilical cord clamping
WHO Recommendation
- Delay of umbilical cord clamping for 1–3 minutes
UK Guidelines
- Delay clamping the umbilical cord earlier than necessary
- (unless exigent circumstances such as heavy maternal blood loss or the need for immediate neonatal resuscitation take priority)
Canadian Guidelines
- The risk of jaundice is weighed against the physiological benefits of delayed cord clamping.
Delayed cord clamping (1-3 minutes) vs immediate (<60 sec) on clinical jaundice
doesn’t increase the risk of clinical jaundice, but increases the percentage of infants who need phototherapy (simulating the sunlight) for it
(from 2.74% to 4.36%)
clinical jaundice
Infant jaundice is yellow discoloration of a newborn baby’s skin and eyes.
Biases in how medical practice (standards of care) change
- Easier to change in the direction of doing (makes reversals common)
- Harder to change in the direction of not doing
- Clinical articles are much more likely to examine new possible medical practices than an already existing standard of care
- The percentage of reversal among articles testing standard of care was 40%
Medical knowledge
- mostly procedural
- some semantic
- semantic knowledge serves the procedural knowledge
- explains why certain practices are adopted and others are not
scientific knowledge
- mostly semantic (our models of the world)
- some procedural
- procedural knowledge serves the semantic knowledge
- prescribes what we should do to update and improve the semantic knowledge
evidence-practice gap
It takes a long time for science to influence medical practice and it only does so partially
Archie Cochrane
- scottish doctor
- criticized the lack of reliable evidence behind many of the commonly accepted healthcare interventions
- advocated for the use of randomized control trials to make medicine more effective and efficient
- led to the development of the Cochrane Library database of systematic reviews
- helped lay the foundation for evidence-based medicine
conclusions from Cochrane Systematic Review about interventions
conclude that there is insufficient evidence to endorse the interventions they examine
Semantic (declarative) knowledge
- Forms and changes based on the ‘evidence’ we are exposed to (the evidence could be biased or faulty)
Procedural knowledge
Forms and changes based on
- what we frequently do (habits)
- the system of incentives and disincentives (rewards and punishments) that are part of our environment
Systems of incentives and disincentives
that influence the practice of obstetrics
- Personal
- Professional
- duty of care
- financial (procedure = $$$)
- medico-legal
duty of care
- an obligation to benefit one’s patients medically
- hippocratic oath!
medico-legal systems of incentives and disincentives
litigation pressures
- fears of getting sued
insurance policies
- dictates what gets done during childbirth
The odds of lawsuits and their outcomes
- Most lawsuits don’t go to trial. Only a fraction do. The rest are settled out of court or dismissed.
- Of those lawsuits that do go to trial, an overwhelming majority are resolved in the Ob/Gyn’s favour.
- Overall, the risk of ‘losing’ the lawsuit are very small for the physician
Negative impacts of lawsuits on Ob/Gyns
- More than half of Ob/Gyns say that their thinking and actions are continuously affected by the threat of lawsuits
- More than half describe being sued as an extremely negative experience
- More than a third agreed that “I no longer trust patients, I treat them different” and in some cases also lost trust in their colleagues and organizations
when do we do studies on practices?
- only after they have been widely adopted… this is a problem
- even when studies are conducted early one, what they actually measure can only be PART of the problem… surrogate outcomes, rather than end points because its simpler and faster
Why does the evidence for a certain medical practice change–and continue to change–over time?
○ Diseases can change over time
past medical education vs the focus that is needed?
past (and kinda present) is mostly just MEMORIZATION!!
- Teaching critical thinking has become central to the curriculum for doctors and other health professionals
- Much greater focus on the need for evidence-based practice
effect of C-section on the baby
In a C-section the baby has little warning that its peaceful world is going to change
Without the preparation of labour, birth is abrupt
when is it most difficult for the birthing person during a C-section?
- after the baby has been delivered
- no longer anticipation to see the baby born
