Obstetrics Flashcards
what is classed as premature labour?
when pregnancy occurs between 24 and 37 weeks gestation.
what are the risk factors for preterm birth?
previous premature labour previous cervical trauma previous induced abortion maternal infection multifetal pregnancies short cervical length positive fetal fibronectin test preterm premature rupture of membranes short interpregnancy interval extremes of maternal age maternal medical disease (renal failure, DM, thyroid disease) pregnancy complications - preeclampsia or IUGR
what is normal labour?
Spontaneous in onset, low-risk at the start of labour and remaining so throughout labour and delivery. The infant is born spontaneously in the vertex position between 37 and 42 completed weeks of pregnancy. After birth, mother and infant are in good condition’
what is a normal birth ?
Birth without induction of labour, spinal or epidural analgesia, general anaesthesia, forceps or ventouse delivery, caesarean section or episiotomy
what is the latent phase of labour?
when there is irregular contractions, the show a mucoid plug
- can last from 6 hours to 2-3 days
cervix is effacing and thinning
encouraged to stay at home
what are the three stages of labour?
the first stage - commences with the onset of labour and terminates when the cervix has reached full dilatation and is no longer palpable
second stage - the stage of expulsion begins with full dilatation of the cervix and ends with expulsion of the fetus
third stage or the placental stage - expulsion of the placenta
what is labour defined as?
Labour may be defined as the onset of regular and painful contractions associated with cervical dilation and descent of the presenting part
what are the signs of labour?
- regular and painful uterine contractions
- a show (shedding of mucous plug)
- rupture of the membranes (not always)
- shortening and dilation of the cervix
what monitoring would you perform during labour?
- FHR monitored every 15min (or continuously via CTG)
- Contractions assessed every 30min
- Maternal pulse rate assessed every 60min
- Maternal BP and temp should be checked every 4 hours
- VE should be offered every 4 hours to check progression of labour
- Maternal urine should be checked for ketones and protein every 4 hours
what is latent and active labour?
latent phase = 0-3 cm dilation, normally takes 6 hours
active phase = 3-10 cm dilation, normally 1cm/hr
what mechanical factors determine the progress of labour?
the degree of of force expelling the foetus
the dimensions of the pelvis and resistence of soft tissue
the diameter of the fetal head
once labour is established how often do contractions occur and what happens during a contraction?
the uterus contacts for 45-60 seconds about every 2-4 minutes
during the contraction the cervix is pulled up (effacement) and caused dilatation, aided by the pressure of the head as the uterus pushes the head down into the pelvis
what are the movements of the head in labour?
every darn fool in egypt eats raw egss
engagement descent flexion internal rotation extension external rotation expulsion
what is a braxton hicks contraction?
involuntary contractions of uterine smooth muscle that occur through the third trimester
what is effacement of the cervix?
when the normally tubular cervix is drawn up into the lower segment until it is flat
what observations should be performed during labour?
FHR monitored every 15min (or continuously via CTG)
Contractions assessed every 30min
Maternal pulse rate assessed every 60min
Maternal BP and temp should be checked every 4 hours
VE should be offered every 4 hours to check progression of labour
Maternal urine should be checked for ketones and protein every 4 hours
what can be done to help quicken
labour progress?
amniotomy and then artificial oxytocin
*if full dilatation is not not imminent within 12-16 hours, usually a c-section is performed
what factors determine how easily the head fits through the pelvis?
attitude: extension/flexion - vertex presentation (well flexed is ideal) the less flexed and more extended makes it harder for head to pass
position - rotation - usually delivered with occiput anterior (other rotations included occipito posterior, occipito-transverse, brow presentation or face presentation)
size of the head
what can cause damage to the fetus during labour?
fetal hypoxia - commonly describes as distress
infection/inflammation in labour - e.g. group b streptococcus
meconium aspiration leading to chemical pneumonitis
trauma is rarely spontaneous and is more commonly due to obstetric interventions e.g. forceps
fetal blood loss
how is hypoxia diagnosed in the fetus during labour?
pH of <7.2 in the fetal scalp blood indicates significant hypoxia
it is actually only when the pH is below 7 that neurological damage is considerably more common
colour of the liquor - if it is meconium stained - more risk of fetal distress as it could aspirate the meconium - closer monitoring with CTG is needed
fetal HR auscultation - the distressed fetus will show abnormal heart rate patterns
CTG
fetal ECG monitoring
what can cause acute hypoxia of the fetus during labour?
placental abruption
hypertonic uterine states and the use of oxytocin
prolapse of the umbilical cord
maternal hypotension
what can be done to help the mother during labour?
entonox - equal mix of NO and O2
systemic opiates - pethidine and Meptid are widely used as IM injections
epidural - administered between L3-4 or L4-5. (can make labour pain free)
how often is the fetal heart rate listened to and whe is a CTG required?
every 15 minutes for 1 minute following a contraction
if the pregnancy is high risk or meconium is seen or if there is a maternal fever then a CTG should be started
in the second stage of labour - FHR should be measure every contraction
what are the observations of the mother in the first and second stage of labour?
fist stage - every 30 minutes measure contraction frequency, every hour - pulse, every four hours - BP, temp, vaginal exam
Second stage - every 15 mins - pulse
what is administered in the third stage of labour?
active management of the third stage
ergometrine and oxytocin
this will reduce risk of postpartum haemorrhage
what are the classifications of perineal trauma from delivery?
first degree - injury to skin only
second degree - involves perineal muscles but not anal sphincter
third degree - involves anal sphincter complex
fourth degree - involves anal sphincter and anal epithelium
what are the disadvantages, complications and contraindications of an epidural?
disadvantages: increased supervision, maternal fever, reduced mobility, increased instrumental delivery rate, hypotension, urinary retention
complications: spinal tap, total spinal analgesia, local anaesthetic toxicity
Contraindications: severe sepsis, coagulopathy, active neuronal disease, hypovolaemia, severe spinal abnormalities, severe cardiac outflow obstruction
what are the complications of premature birth?
ICU needed perinatal mortality cerebral palsy chronic lung disease blindness
what is periventricular leukomalacia?
Periventricular leukomalacia (PVL) is a type of brain injury that is most common in babies born too soon (premature) or at low birthweight. The white matter (leuko) surrounding the ventricles of the brain (periventricular) is deprived of blood and oxygen leading to softening (malacia). The white matter is responsible for transmitting messages from nerve cells in the brain so damage to the white matter can cause problems with movement and other body functions.
what are some of the mechanisms for preterm labour?
the castle model
- ‘too many defenders’ - multiple pregnancy (excess liquor, polyhydramnios has the same effect)
- ’ the defenders give up’ - spontaneous preterm labour is more common where the fetus is at risk e.g. preeclampsia and IUGR or if there is an infection
- ‘the castle design is poor’ - uterine abnormalities
- ’ the castle wall is weak’ - cervical invcompetence
- ‘the enemy knock down the wall’ infection
how is preterm labour prevented?
preterm labour prevention is really only aimed at those who are high risk - the strategies should begin by 12 weeks
- cervical cerclage - insertion of sutures into the cervix to strengthen and keep it closed
- progesterone supplememntation
- screen and treat STI’s, UTIs, BV
- treat polyhydramnios - by needle aspiration
when can cervical cerclage be used?
it can be done elective at 12-14 weeks
or the cervix can be scanned regularly and when there is significant shortening it can be sutured
finally it can be used as a rescue suture - can prevent delivery when the cervix is widely dilated
what test can be used to assess whether birth in the next week is likely?
fetal fibronectin assay (present in cervical secretions )
positive = birth likely in the next 7 days
in which women is steroids prescribed to ?
given to women between 23 and 34 weeks
*in woman presenting with only contractions, they can be restricted to those who are fibronectin positive or have a short cervix
why are steroid prescribed?
they reduce perinatal morbidity and mortality by promoting pulmonary maturity
what is tocolysis?
nifedipine or oxytocin receptor antagonists (e.g. atosiban)
tocolytics are given to suppress premature labour by suppressing uterine contraction
why are tocolytics given?
they are given to allow steroids time to act, or to allow time for transfer to a unit with neonatal intensive care facilities
* should only be given for a max of 24 hours
what can be given as a neuroprotective for the neonate?
magnesium sulphate
given <12 hours prior to anticipated or planned preterm delivery
a single dose of 4g by slow IV injection is used prior to delivery between 23 and 34 weeks
what are the two classifications of premature rupture of membranes?
premature rupture of membranes (PROM) - the rupture of fetal membranes at least 1 hour prior to onset of labour >/ 37 weeks’ gestation. It occurs in 10-15% of term pregnancies and is associated with minimal risk
Preterm premature rupture of membranes (P-PROM) - the rupture of fetal membranes occurring less than 37 weeks gestation.
what can lead to PROM and P-PROM?
early activation of the normal physiological process - higher than normal level of apoptotic markers and MMPs in the amniotic fluid
Infection - inflammatory markers contribute to the weakening of the fetal membranes
genetic predisposition
what are the risk factors for PROM/P-PROM?
often none identifiable smoking (especially <28 weeks gestation) previous PROM/preterm delivery vagiunal bleeding during pregnancy lower genital tract infection invasive procedure - amniocentesis polyhydramnios multiple pregnancy cervical insufficiency
what are the clinical features of PROM?
- women experiences a painless popping sensation - followed by a gush of watery fluid leaking from the vagina
- symptoms can be more non-specific, such as gradual leakage of watery fluid from the vagina and damp underwear, or a change in colour or consistency of vaginal discharge
what are the complications of P-PROM?
preterm delivery is the main complication - follows within 48 hours in 50% of cases
infection of the fetus or placenta (chorioamnionitis) or cord (funisitis)
rarely there may be prolapse of the umbilical cord
how would you diagnose PROM?
usually from maternal hisory and positive exam findings
digital exam should be avoided
take high vaginal swab to check for infection
point of care tests - actim-PROM
what antibiotic is contraindicated in prevention infection in PROM?
amoxicillin/Co-amoxiclav is contraindicated, as the neonate is more prone to necrotising enterocolitis (NEC)
how do you manage P-PROM?
the woman should be admitted for 48 hours and be given steroids
> 36 weeks - monitor signs of clinical chorioamnionitis. If there is evidence of group B streptococcus - give clindamycin/penicillin. induction of labour is recommended if greater than 24 hours.
34-36 weeks - monitor for signs of clinical chorioamnionitis, and advise to avoid sexual intercourse. Prophylactic erythromycin should be given, corticosteroids should be given.
IOL and delivery often recommended
24-33 weeks - monitor for signs of clinical chorioamnionitis and advise patients to avoid sexual intercourse
Prophylactic erythromycin
what are the indications for induction of labour?
- prolonged pregnancy, e.g. > 12 days after estimated date of delivery
- prelabour premature rupture of the membranes, where labour does not start
- diabetic mother > 38 weeks
- rhesus incompatibility
- pre-eclampsia
- suspected growth restrictions
how can labour be induced?
- intravaginal prostaglandins
- cervical sweep
- breaking of water amd oxytocin
what are the contraindications for induction of labour?
acute fetal compromise
abnormal lie
placenta praevia
pelvic obstruction
what score can be used to predict if induction of labour will be required?
BISHOP score
cervical position (0=posterior, 1=intermediate, 2=anterior) cervical consistency (0=firm, 1=intermediate, 2= soft)
Cervical effacement (0-30%=0, 40-50%=1, 60-70%=2, 80%=3)
cervical dilation (<1cm=0, 1-2cm=1, 3-4cm=2, >5cm=3)
fetal station (-3=0, -2=1, -1/0=2, +1+2=3)
score <5 indicates that labour is unlikely to start without induction
a score >9 indicated that labour will most likely commonce spontaneously
what is the definition of a spontaneous miscarriage?
when the fetus dies or delivers dead before 24 completed weeks of pregnancy
when do the majority of miscarriages occur by?
the majority occur before 12 weeks
what percentage of pregnancies miscarry?
15%
what are the different types of miscarriage?
threatened miscarriage: there is bleeding but the fetus is still alive, the uterus is the size from the dates and the cervical os is closed. Only 25% will go on to miscarry
inevitable miscarriage: bleeding is usually heavier. although the fetus may still be alive the cervical os is open and miscarriage is about to occur
incomplete miscarriage: not all products of conception have been expelled, pain and vaginal bleeding,
cervical os is open
complete miscarriage - all fetal tissue has been passed. Bleeding has diminished, the uterus is not longer enlarged and the cervical os is closed
septic miscarriage - the contents of the the uterus are infected, causing endometriosis. Vaginal loss is usually offensive, the uterus is tender, but a fever can be absent .
Missed miscarriage - a gestational sac which contains a dead fetus before 20 weeks without the symptoms of expulsion
mother may have light vaginal bleeding / discharge and the symptoms of pregnancy which disappear. Pain is not usually a feature
cervical os is closed
when the gestational sac is > 25 mm and no embryonic/fetal part can be seen it is sometimes described as a ‘blighted ovum’ or ‘anembryonic pregnancy’
what symptoms would make you want to exclude and ectopic pregnancy?
pain
hypotension
tachycardia
anaemia
what are some causes of miscarriage?
embryonic factors - (embryonic disease, disorder or damage, chromosomal abnormalities, embryonic malformations)
maternal factors (maternal genital tract dysfunction or systemic illness, exposure to high doses of toxic agents)
what is the definition of recurrent miscarriage?
The spontaneous loss of ≥3 consecutive pregnancies before 20-24 completed weeks (gestation depends on country) is regarded as recurrent miscarriage.
what are some risk factors for miscarriage?
older age uterine malformation bacterial vaginosis thrombophilia chromosomal abnormality previous miscarriage infertility/assisted conception NSAIDs caffeine alcohol DM
what investigations would you perform for suspected miscarriage?
pregnancy test
FB
serum beta hCG titres
transvaginal USS
what are the classifications of miscarriage in terms of time?
Biochemical pregnancy loss: Typical gestation <6 weeks No fetal activity ever detected Pregnancy not located on ultrasound Beta hCG levels are high and then fall.
Early pregnancy loss:
Gestation typically 6 to 8 weeks
No fetal activity ever detected
Empty sac or large sac with minimal structures without fetal heart activity
Beta hCG levels show an initial rise and then fall.
Late pregnancy loss:
Typical gestation >12 weeks
Loss of fetal heart activity
Crown to rump length and fetal heart activity previously identified.
how do you manage a miscarriage?
*antiD is given to all woman who are rhesus negative if the miscarriage is treated surgically or medically or if there is bleeding after 12 weeks
Expectant management:
First line and involves waiting for 7-14 days for the miscarriage to complete spontaneously
Medical management:
Give the patient vaginal misoprostol. Advise them to contact the doctor if the bleeding hasn’t started in 24 hours. Should be given with antiemetics and pain relief. Often preferred if there is a higher risk of haemorrhage (late first trimester or coagulopathies), evidence of infection or previous adverse experiences.
Surgical management:
May involve manual vacuum aspiration under local anaesthetic as an outpatient or surgical management in theatre under general anaesthetic (previously referred to as ERPC).
what are some causes of recurrent miscarriage?
antiphospholipid syndrome
endocrine disorders - poorly controlled DM, thread disease or PCOS
uterine abnormalities e.g. uterine septum
parental chromosomal abnormalities
smoking
how can you manage antiphospholipid syndrome to prevent recurrent miscarriage?
aspirin and low dose molecular weight heparin
why does glucose tolerance decrease during pregnancy?
during pregnancy resistance to insulin action increases
** in most pregnancies, pancreatic beta cells are able to compensate for increased insulin demands
what is gestational diabetes?
traditionally it has been defined as any degree of glucose intolerance with onset or first recognition during pregnancy
what factors can increase the risk of gestational diabetes?
age - due to age-related decreased pancreatic beta-cell reserve
obesity - leads to increased insulin resistance
smoking
PCOS - associated with insulin resistance and obesity
fam history of T2DM
previous GDM
what are the clinical features of gestational diabetes?
Most woman with borderline pancreatic reserve will be asymptomatic and will show no signs of Gestational diabetes.
If present, the clinical features tend to be the same as other forms of diabetes. – polyuria, polydipsia and fatigue.
what are the fetal complications of gestational diabetes?
glucose crosses placenta but insulin does not -fetus will therefore increase its own insulin levels to compensate - excess insulin can cause
- macrosomia
- organomnegaly
- eryhtropoiesis (results in polycythaemia)
- polyhydramnios
- increases rate of preterm delivery
- risk of hypoglycaemia at birth
- decreased surfactant production - risk of tachypnoea
who is screened for gestational diabetes?
those who have previously had gestational diabetes and those who have any of the other risk factors should be screened at 24-28 weeks with an oral glucose tolerance test
what are the fasting a 2 hour glucose levels for GDM to be diagnosed?
fasting - glucose level of >5.6mmol/L
a 2 hour plasma glucose level >7.8mmol/L
how is gestational diabetes managed?
1st line - lifestyle (diet and exercise and glucose monitoring)
2nd line - insulin therapy - for those with uncontrolled dietary therapy or marked initial hyperglycaemia
additional growth scans at 28,32 and 36 weeks
aim to deliver at 37 to 38 weeks
what is the post natal care for gestation diabetes?
- All anti-diabetic medication should be sopped immediately after delivery
- The blood glucose levels should be measured before discharge to check it has returned to normal
- Around 6-13 weeks post-partum, a fasting glucose test is recommended.
- Yearly tests should be offered due to increased risk of developing diabetes in the future.
