Pregnancy and Labour Flashcards
how many stages are there in labour?
three
which two hormones are responsible for the initiation of labour?
oxytocin
prostaglandins
what is the average diameter of the cervix when fully dilated?
10cm
what is the physiological and active management of the third stage of labour?
physiological: maternal effort only
active: uterotonic drugs, cord clamping, cord traction
what are the physiological changes in the uterus that allow labour to start?
- cervix thins and softens
- myometrial tone changes to allow contractions
- progesterone decreases and prostaglandins/oxytocin initiate contractions
what is the latent first stage of labour?
it is the period from the beginning of contractions until the cervix is dilated to 5cm
what is the established first stage of labour?
it is the period during which cervix is dilated from 5cm to full dilation of 10cm
when is the first stage of labour complete?
the cervix is fully dilated
what is the passive second stage of labour?
it is the period during which cervix is fully dilated before the start of expulsile contractions
what is the active second stage of labour?
it is the period during which expulsile contractions occur and maternal effort is used
when is the second stage of labour complete?
when the baby is delivered
what is the third stage of labour?
it is the period from the birth of the baby until placenta and membranes are expelled
during which stage of labour does the cervix start to soften and become thinner?
during the latent first stage of labour
when is a diagnosis of prolonged third stage of labour made?
if membranes haven’t been expelled:
- within 30 mins with use of active management
- within 60 mins with use of physiological management
name a few ways the progress of labour is monitored
- maternal observation
- abdominal examination
- vaginal examination
- liquor monitoring
- auscultation of fetal heart
- CTG
- use of partogram
what is crowning?
it’s the point during delivery when the widest point of the baby’s vertex comes through the narrowest part of the pelvic inlet
what anatomical feature of baby is used to determine its position during delivery?
posterior fontanelle
name a few non-pharmaceutical ways to manage analgesia during labour
- breathing exercises
- aromatherapy
- massages
- water birth
- TENS
name a few pharmacological ways to manage analgesia during labour
- paracetamol
- dihydrocodeine
- entonox (nitrous oxide)
- remifentanil
- opioids
what are the 7 movements that make up the mechanism of labour?
- engagement
- descent
- flexion
- internal rotation
- extension
- external rotation
- expulsion
which 9 diseases are currently screened for with a blood spot in newborns?
- phenylketonuria (PKU)
- sickle cell disorders
- medium chain Acetyl-CoA Dehydrogenase deficiency (MCADD)
- congenital hypothyroidism
- cystic fibrosis
- maple syrup urine disease
- homocysteinuria
- isovaleric acidaemia
- gluratic aciduria type 1
what is a common condition in mum that might require induction of labour?
diabetes
what is the score used to assess how ripe a cervix is during labour?
Bishop’s score
what is the role of prostaglandins during labour?
they help the cervix to ripen
what is the role of oxytocin during labour?
it helps develop contractions
what is an amniotomy?
artificial breaking of the fetal membranes during labour
what is the ideal position for the baby’s head when it descends?
occipito-anterior
why might labour be abnormal because of problems with power?
- underactive uterus
why might labour be abnormal because of problems with passage or passenger?
- malpresentation
- malposition
- cephalopelvic disproportion
what does malpresentation mean in terms of abnormal labour?
baby is not presenting with vertex lie (ie transverse or breech)
what does malposition mean in terms of abnormal labour?
baby’s head is in incorrect position for labout (ie not occipito-anterior)
in terms of causes for abnormal labour, is malpresentation or malposition more common?
malposition is more common
name a few ways fetal well-being can be monitored during induced labour
- auscultation
- cardiotocography (CTG)
- fetal blood sampling
- fetal ECG
when is a fetal blood sample taken during labour?
it’s done when CTG is abnormal
what are some of the main indications not to undergo labour?
- placenta praevia
- masses or other obstruction
- malpresentation
- previous labour complications
when are ventouse or forceps deliveries of babies carried out?
when the baby’s head is in malposition
what is the management of a retained placenta?
oxytocin to induce contractions or manual removal of placenta
what are the main complications in the third stage of labour?
- retained placenta
- tears
- post partum haemorrhage
what are the four major causes of primary post partum haemorrhage?
Trauma
Tissue
Tone
Thrombin
what is the definition of primary post partum haemorrhage?
loss of >500ml blood within first 24 hours of delivery
what is the definition of secondary post partum haemorrhage?
loss of >500ml blood between 24 hours and 6 weeks after delivery
why are swollen legs or SoB in pregnancy or postpartum worrying?
because they might indicate a VTE (DVT or PE)
name a few serious conditions to be aware of in postpartum women
- post partum haemorrhage
- venous thromboembolism
- sepsis
- puerperal depression/psychosis
- pre-eclampsia/eclampsia
how does pregnancy affect the cardiovascular system?
- increased blood volume/flow
- increased cardiac output
- increased stroke volume
- increased heart rate
- decreased total peripheral resistance
- blood pressure drop
- lung/peripheral oedema
why is there a decrease in total peripheral vascular resistance in pregnancy?
because progesterone causes vasodilation
apart from mechanical strain from the fetus weight and resulting posture, what is another reason for joint and back pain in pregnancy?
progesterone loosens ligaments which can result in pain
how does pregnancy affect the blood components?
- increase of red cell count by half
- increased requirement of folate and iron
- increased plasma volume
- decreased haematocrit, haemoglobin
- decreased platelets
- increased WBC
- increased coagulation factors 8, 9 and 10
- protein loss
what causes pregnancy to be a hypercoagulable state and why is that beneficial?
because there is an increase in coagulation factors 8, 9 and 10
it minimises the risk of bleeding during delivery
how does pregnancy affect the renal system?
- massive increase in size of collecting system
- increase in kidney size (hydronephrosis)
- increase in ureter diameter (hydroureter)
- increase in GFR and creatinine clearance
- reduced urea and creatinine
- increased urate
- proteinuria/microscopic haematuria
- increased renal plasma flow -> urinary frequency
- urinary stasis –> increased risk of infections
what causes urinary frequency in pregnancy?
- massive increase in renal plasma flow
- decrease in bladder volume due to compression by uterus
why is there a higher risk of UTIs in pregnant women?
because there is urinary stasis as a result of the increase in plasma volume and enlarged kidneys/ureter
what characterises shortness of breath in pregnancy?
it occurs at rest and gets better on movement
why does blood volume almost double during labour and delivery?
because each contraction results in more blood being squeezed into the circulation (up to 500ml per contraction)
how should a pregnant woman NOT be examined and why?
NEVER examine a pregnant women flat on her back, because the weight of the baby will compress her IVC
what is colostrum and what does it contain?
it’s the first milk secreted from the mum’s breast during pregnancy
it contains a high number of calories and IgA to be passed onto the baby
what causes the linea nigra to appear and the nipples to become darker in colour?
increased melanocyte production by anterior pituitary
what promotes colostrum production?
prolactin release from anterior pituitary
where is oxytocin produced?
posterior pituitary
which liver enzyme is massively increased during pregnancy and why?
Alkaline phosphatase (ALP) - secreted by placenta
what is a common finding on a urine dipstick in pregnancy?
glycosuria
how is the thyroid affected during pregnancy?
can become hypoactive
name a few common GI changes during pregnancy?
cardiac sphincter relaxes
gastric emptying slows down
GI motility reduced –> heartburn/reflux
where do ectopic pregnancies most commonly occur?
in fallopian tube
what is a molar pregnancy?
it’s the fertilisation of an empty ovum by a sperm, causing the implantation of a non-viable egg
what is the pathophysiology of a molar pregnancy?
methylated genes from the dad are not balanced with the methylated genes from the mum as the ovum is empty.
this causes abnormal proliferation of trophoblast cells and placenta
what is the role of trophoblast cells and decidual cells during egg implantation in the uterus?
- trophoblast cells invade the decidua and guide chorionic villi into the tissue
- decidual cells act as pro-coagulants to stop bleeding caused by trophoblast cells invading the tissue
what medical treatment can be given for an ectopic pregnancy?
methotrexate
what do trophoblast cells secrete?
beta HCG
which test can be carried out in utero to diagnose Trisomy 21?
amniocentesis
feature of babies born from mums with poorly controlled diabetes?
very large babies, broad shoulders
“diabetic cherub”
what is a common cause of cerebral palsy in newborns?
infection during labour
what is the main concern for fetus in placental abruption?
hypoxia
name a few causes of placental abruption
smoking old maternal age hypertension cocaine use trauma
what is the pathophysiology of hypertension due to pregnancy?
- trophoblast cells damage blood vessels in placenta, causing vaconstriction
- vasoconstriction causes a drop in oxygen supply to placenta,
- placental hypoxia triggers an increase in blood pressure to overcome the vasoconstriction and deliver oxygen to placenta
what is the definition of a miscarriage?
intrauterine death of fetus before 24 weeks of gestation
what are the six types of sponatenous miscarriage?
- threatened
- inevitable
- incomplete
- complete
- septic
- missed
define a threatened miscarriage
bleeding from uterus before 24 weeks, with cervix closed
define an inevitable miscarriage
loss of fetus due to dilated cervix before 24 weeks
define an incomplete miscarriage
loss of fetus but placenta and membranes have not been expelled
define a complete miscarriage
all products of conception are expelled and cervix closed again
define a septic miscarriage
infection in uterus/pelvis following an incomplete miscarriage
define a missed miscarriage
death of fetus but no expulsion
name a few possible causes of spontaneous miscarriage
- fetal abnormalities
- uterine abnormalities
- maternal disease/hormonal imbalance
- cervical incompetence
- idiopathic
management of miscarriage?
removal of leftover conceptus in uterus (either medically or surgically)
define an ectopic pregnancy
implantation of embryo outside of uterus
name a few risk factors for ectopic pregnancies
- previous infections
- previous pelvic surgery
- previous ectopic
why are infections and previous fallopian tube surgery a risk factor for ectopic pregnancy?
because scarring can cause narrowing of the fallopian tube and obstruct passage of embryo
how is an ectopic pregnancy identified?
- USS scan
- beta HCG levels
- progesterone levels
in an ectopic pregnancy, how do beta HCG and progesterone levels compare to normal pregnancy levels?
- beta HCG increases rapidly in pregnancy. in ectopics it doesn’t
- progesterone is lower in ectopic pregnancy than in normal pregnancy
how are ectopic pregnancies managed?
- conservatively (on mum’s request)
- methotrexate
- salpingotomy/salpingectomy
what is the difference in medical treatment between ectopic pregnancies and miscarriages?
ectopic pregnancy - methotrexate to shrink conceptus
miscarriage - misoprostol (prostaglandins) to induce expulsion of conceptus
what is misoprostol?
a synthetic prostaglandin used to induce labour/uterine contractions
define antepartum haemorrhage
bleeding from uterus after 24 weeks of gestation but before delivery
name a few causes of antepartum haemorrhage
- placenta praevia
- placental abruption
- idiopathic
- localised trauma
how many grades of placenta praevia are there? give a brief description of each
1 - placenta near os
2 - placenta on edge of os
3 - placenta covers os
4 - placenta central over os
what are the three ways placental abruption can present?
concealed - haematoma behind placenta
revealed - placenta comes away from the edge
mixed - concealed and revealed
how does a placenta praevia present?
- can be found incidentally
- PAINLESS bleeding
- malpresentation of baby
how is placenta praevia identified?
by ultrasound scan
what examination should not be done in mums with placenta praevia, and why?
vaginal examination - because it may result in more bleeding
what are the two main clinical differences between placenta praevia and placental abruption?
- placenta praevia is PAINLESS, abruption is painful
- clinical presentation much more severe in placental abruption, whereas in placenta praevia mum is well unless there is severe bleeding
what complication can occur in placenta praevia and why?
post partum haemorrhage, because lower part of uterus doesn’t contract as well as upper part, preventing vasosonctriction of placental blood vessels
how is post partum haemorrhage treated?
- with uterotonics (oxytocin, ergometrine)
- with a balloon tamponade
- with surgery
name a few risk factors for placental abruption
- previous abruption
- pre-eclampsia/hypertension
- polyhydramnios
- smoking
- increasing age
- multiparity
- cocaine use
which type of placental abruption is most common?
mixed concealed and revealed
how does placental abruption present?
PAINFUL bleeding
in which type of placental abruption is there normally no PV bleeding?
in concealed placental abruption
how is placental abruption managed?
managed depending on gestation, maternal/fetal wellbeing and amount of bleeding
options include waiting, induction of labour, cesarean
name a few complications of placental abruption
- postpartum haemorrhage
- circulatory shock
- fetal death
- DIC
when is labour classed as preterm?
when it occurs before 37 completed weeks of gestation
how is pre-term labour managed?
- tocolysis to slow down labour
- steroids to help preterm baby to develop quicker
- prepare for vaginal delivery
what are the main signs of pre-eclampsia?
- onset of hypertension after 20 weeks of gestation up to 6 weeks post delivery
- proteinuria
name a few symptoms associated with pre-eclampsia
- headaches
- blurred vision
- RUQ pain
- oedema
- vomiting
- clonus
- hyperreflexia
what are the HELLP signs in severe pre-eclampsia?
haemolysis
elevated liver enzymes
low platelets
what investigation are done to diagnose pre-eclampsia?
- blood pressure readings
- urine dipstick
- FBC (RBC, platelets)
- liver function tests
- kidney function tests
- neuro exam for clonus and hyperreflexia
why is it important to monitor women post-pregnancy for pre-eclampsia?
because over 40% of eclamptic seizures occur during the 6 weeks post-partum
what is the medical treatment for women having an eclamptic fit?
magnesium sulphate
what is the management of pre-eclampsia?
delivery of baby
name a few potential complications of pre-eclampsia
stroke renal failure liver failure seizures pulmonary oedema DIC heart failure
what is gestational hypertension?
hypertension that starts after 20 weeks of pregnancy but stops after delivery
what is the difference between gestational hypertension and pre-eclampsia?
presence of proteinuria in pre-eclampsia, not present in gestational hypertension
name a few risk factors for developing pre-eclampsia
- first pregnancy or long interval since last pregnancy
- obesity
- hypertension
- renal failure
- diabetes
- previous pre-eclampsia
- family history of pre-eclampsia
why can women with pre-eclampsia present with hyperreflexia and clonus?
because vasoconstriction and oedema can cause increased intracranial pressure and cerebral irritation
how can you screen for gestational diabetes?
monitor HbA1C
oral glucose tolerance test
what is the prophylactic VTE management in pregnant women?
compression stockings
advice on mobility and hydration
at which stage of gestation is a heart beat present?
6 weeks
when is the dating scan carried out?
between weeks 11 and 14
what information can be obtained from the dating scan?
- due date
- multiple pregnancies
- molar/ectopic pregnancy
- miscarriage
- anencephaly
- chromosomal abnormalities
- neural tube defects
when can the fetus be tested for Down’s Syndrome?
between weeks 11-14
what are the tests done to identify the fetus’ risk of having Down’s Syndrome?
Combined Ultrasound and Biochemical screen (CUBS):
- Ultrasound: Nuchal Translucency test
- Biochemical test: hCG, PAPP-A
when is the anomaly scan carried out in pregnancy?
week 20
what can the anomaly scan identify?
structural abnormalities
name a few abnormalities the anomaly scan can identify during pregnancy
duodenal atresia cleft lip spina bifida renal agenesis diaphragmatic hernia exomphalos gastroschisis
what is the first sign of pregnancy visible on ultrasound?
thickening of endometrium
how is the gestation of a fetus measured during the first trimester scan?
crown-rump length of fetus is measured, which roughly coincides with gestation length
if mum comes for a pregnancy scan between weeks 15 and 20, what can she be offered to identify risk of neural tube defects and Down’s syndrome?
blood test for alpha-fetoprotein, hCG, inhibin and unconjugated oestriol
what should the crown rump length of baby be for a nuchal translucency test?
45-84mm
is there a routine ultrasound scan done during the third trimester?
no
what is the purpose of an ultrasound scan during the third trimester?
monitoring babies who are too small or too large for their gestation time, or for other potential problems
how can fetal growth be measured during a third trimester scan?
head circumference
femur length
abdominal length
what does the baby’s head look like if there is a neural tube defect?
- frontal bossing
- lemon shaped head
which neural tube defect can be detected during the first trimester?
anencephaly
what is the first trimester ultrasound scan called?
dating scan
what is the second trimester ultrasound scan called?
detailed anomaly scan
what is the rate of detection of fetuses with Down’s syndrome using the CUBS tests?
85%
what is the rate of neural tube defect detection during the second trimester scan?
90%
which protein is raised in mum’s blood if the fetus has a neural tube defect?
alpha fetoprotein
if a CUBS test shows a fetus is at high risk of having Down’s syndrome, what other more invasive tests can be carried out and when?
chorionic villus sampling - week 10-14
amniocentesis - after week 15
name a few aims of pre-pregnancy counselling
- optimise physical/psychiatric health
- optimise BMI/diet
- reduce alcohol consuption
- smoking cessation
- review medications
- address pre-existing conditions
if mum had a DVT during previous pregnancy, what action is taken to prevent risk in new pregnancy?
thromboprophylaxis - LMWH
if mum had pre-eclampsia during previous pregnancy, what action is taken to prevent risk in new pregnancy?
blood pressure monitoring
low dose aspirin
what pregnancy complication can be identified from a MSSU?
- bacteriuria (UTI)
- proteinuria (pre-eclampsia)
- glycosuria (diabetes)
- alpha feto protein (neural tube defect)
after which week of pregnancy is it sometimes necessary to discuss termination of pregnancy due to severe fetal abnormalities?
after week 20 (anomaly scan)
which infections are screened for as part of the antenatal examination?
- rubella
- HIV
- syphilis
- hepatitis B
- UTI
what is the main contributing risk factor that to the chance of fetus having Trisomy 21?
maternal older age
what type of maternal death is most common in the UK?
indirect death - caused by comorbidities exacerbated by pregnancy
what type of maternal death is the most common worldwide?
direct death - caused by complications of pregnancy/labour
