Normal Labour and Delivery Flashcards

1
Q

what should you ask a woman when she presents to L&D

A

contractions
vaginal bleeding
leakage of fluid
fetal movement

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2
Q

what physical exam should you do on L&D

A

determine fetal lie (longitudinal, transverse)

determine fetal presentation (breech or cephalic)

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3
Q

in what % of pregnancies to membranes rupture before onset of labour

A

10%–> “premature rupture of membranes” (PROM)

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4
Q

define prolonged PROM…why do we care?

A

prolonged PROM is rupture 18 hours before onset of labour

greater risk of infection to both mother and fetus

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5
Q

what aspects of history suggest rupture of membranes

A

gush of, or leaking of, fluid from the vagina

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6
Q

how do you confirm ROM

A

pool, nitrazine or fern tests

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7
Q

what is the pool test

A

for ROM

collection of fluid found in the vagina on examination of the vaginal vault on sterile speculum exam

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8
Q

what is the nitrazine test

A

for ROM

vagina is normally acidic–> amniotic fluid is alkaline

when amniotic fluid comes in contact with nitrazine paper, paper turns blue

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9
Q

what is the fern test

A

for ROM

the estrogens in the amniotic fluid cause crystallization of the salts in the amniotic fluid when it dries

under low microscopic power, crystals resemble blades of a fern

DO NOT sample directly from cervix (cervical fluids also fern)

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10
Q

how do you confirm for sure if there was ROM if the other tests are equivocal

A

inject dilute indigo carmine dye into the amniotic sac to look for leakage of fluid from the cervix onto a tampon

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11
Q

list the 5 components of the cervical exam

A
dilation 
effacement
fetal station
cervical position
consistency of the cervix
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12
Q

what is the Bishop score

A

determined by the 5 aspects of the cervical exam

Bishop score above 8 is consistent with a cervix favorable for both spontaneous labour and induced labour

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13
Q

what part of the cervix is assessed for dilation

A

internal os

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14
Q

define effacement of the cervix

A

subjective

how much length is left of the cervix and how thinned out it is

commonly reported by percent or by cervical length

typical cervix is 3-5 cm in length –> if cervix feels about 2 cm, then it is about 50% effaced

100% effacement occurs when cervix is as thin as the adjoining lower uterine segment

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15
Q

define fetal station

A

relation of the fetal head to the ischial spines

zero station is at the spines

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16
Q

define Bishop score 0 with respect to:

  1. cervix dilation
  2. cervical effacement
  3. station
  4. cervical consistency
  5. cervical position
A
  1. closed
  2. 0-30%
  3. -3
  4. firm
  5. posterior
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17
Q

define Bishop score 1 with respect to:

  1. cervix length
  2. cervical effacement
  3. station
  4. cervical consistency
  5. cervical position
A
  1. 1-2 cm dilated
  2. 40-50% effaced
  3. -2
  4. medium
  5. mid
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18
Q

define Bishop score 2 with respect to:

  1. cervix length
  2. cervical effacement
  3. station
  4. cervical consistency
  5. cervical position
A
  1. 3-4 cm dilated
  2. 60-70% effaced
  3. -1, 0 station
  4. soft
  5. anterior
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19
Q

define Bishop score 3 with respect to:

  1. cervix length
  2. cervical effacement
  3. station
  4. cervical consistency
  5. cervical position
A
  1. more than 5 cm dilated
  2. more than 80% effaced
  3. +1 station or more
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20
Q

reference point for fetal face presentations

A

chin

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21
Q

reference point for fetal breech presentations

A

fetal sacrum

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22
Q

shape of anterior fontanelle

A

diamond

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23
Q

shape of posterior fontanelle

A

triangle

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24
Q

define labour

A

regular contractions that cause cervical change in either effacement or dilation

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25
Q

define prodromal labour

A

“false labour”

irregular contractions that vary in duration, intensity and intervals and yield little to no cervical change

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26
Q

define induction of labour

A

attempt to begin labour in non labouring patient

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27
Q

define augmentation of labour

A

intervening to increase the already present contractions

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28
Q

what agents do you use to induce labour

A

prostaglandins
oxytocin
mechanical dilation of the cervix
and/or artificial ROM

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29
Q

what are the indications for induction of labour

A
post dates
preeclampsia
diabetes mellitus
non reassuring fetal testing
IUGR
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30
Q

what should you do to help prepare the cervix for induction

A

prostaglandins–> i.e PGE2 pessary (Cervidil) or PGE1 (misoprostol)

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31
Q

contraindications for the use of prostaglandins to ripen the cervix in induction

A

asthma or glaucoma in mom

prior cesarean delivery

non reassuring NST

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32
Q

what do you have to watch for when rupturing membranes with the amniotic hook

A

prolapse of the umbilical cord

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33
Q

how do you augment labour

A

with rupture of membranes or with oxytocin

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34
Q

how could you measure strength of contractions

A

with intrauterine pressure catheter (IUPC)

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35
Q

normal range for fetal HR

A

110-160

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36
Q

what does fetal tachy suggest

A

infection
hypoxia
anemia

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37
Q

what low fetal heart rate might we be worried about

A

decel longer than 2 min with rate below 90

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38
Q

describe an approach to NSTs

A
  1. baseline
  2. variations from baseline (variability) –> absent (less than 3 bpm), minimal (3-5), moderate (above 6) or marked (above 25)
  3. accelerations of at least 15 beats per min over baseline that last at least 15 seconds (2 in 20 min)
  4. decelerations
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39
Q

list the 3 types of decelerations

A

early
late
variable

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40
Q

define early deceleration and what causes it

A

begin and end approx same time as contractions

due to increased vagal tone secondary to head compression during contraction

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41
Q

define variable deceleration and what causes it

A

can occur at any time

tend to drop more quickly (be sharper) than early or late decels

due to umbilical cord compression

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42
Q

define late decelerations and what causes them

A

begin at the peak of a contraction and slowly return to baseline after contraction finished

due to uteroplacental insufficiency and are most worrisome

may degrade into bradys as labour progresses, especially with stronger contractions

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43
Q

when might you use a fetal scalp electrode

A

if having repeat decels or if difficult to get reading with doppler

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44
Q

what is the baseline intrauterine pressure

A

10-15 mmHg

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45
Q

how much does intrauterine pressure change during contractions

A

increase 20-30 mmHg in early labour and 40-60 mmHg in later labour

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46
Q

what values are reassuring and non reassuring for a fetal scalp pH

A

reassuring above 7.25

indeterminate 7.2-7.25

nonreassuring below 7.2

can be indicative of hypoxia and acidemia

47
Q

name the cardinal movements of labour

A

engagement

descent

flexion

internal rotation

extension

external rotation (restitution/resolution)

48
Q

cardinal movements of labour definition:

engagement

A

fetal presenting part enters pelvis

49
Q

cardinal movements of labour definition:

descent

A

presenting part into pelvis

50
Q

cardinal movements of labour definition:

flexion

A

allows the smallest diameter to present to the pelvis… ideally chin to chest movement

51
Q

cardinal movements of labour definition:

internal rotation

A

with descent into pelvis, fetal head goes from OT position to OA (ideally) via internal rotation

disruption or absence of this movement can lead to a feturs maintained in OT or malrotation to OP

52
Q

cardinal movements of labour definition:

extension

A

as vertex passes beneath and beyond the pubic symphysis, it will extend to deliver

53
Q

cardinal movements of labour definition:

restitution/resolution

A

once the head delivers, will undergo external rotation and shoulders may be delivered

54
Q

how many stages are there in labour and delivery

A

3 stages

55
Q

when does stage 1 of labour begin

A

with onset of labour and lasts until dilation and effacement complete

56
Q

when does stage 2 of labour begin and end

A

full dilation to delivery of infant

57
Q

stage 3 of labour

A

delivery of infant to delivery of placenta

58
Q

length of average first stage of labour

A

10-12 hours–nulliparous

6-8 hours–multiparous

59
Q

define latent phase of stage 1 labour

A

onset of labour until 3-4 cm dilated

slow cervical change

60
Q

define active phase of stage 1 labour

A

from 3-4 cm dilated until 9 cm dilation

faster cervical change –at least 1 cm /hour of dilation in nulliparous and 1.2 cm/hour in multiparous

61
Q

what are the 3 Ps that determine the transit time during active labour

A

powers–> strength and frequency of uterine contractions

passenger–> fetus size and position

pelvis–> pelvic size and position

62
Q

define cephalopelvic disproportion

A

CPD

if infant too large for pelvis

if rate of cervical change is less than 1 cm/hour, should assess 3 Ps to determine if vaginal delivery is viable

63
Q

what is an adequate strength of uterine contraction

A

200 montevideo units

64
Q

define active phase arrest

A

no change in either cervical dilation or station for 2 hours in setting of adequate montevideo units during active phase of labour–> common indication for section

some women, if you give them up to 4 more hours, will go on to deliver vaginally however

65
Q

define prolonged second stage of labour

A

longer than 2hours in nulliparous woman (3 hours if have epidural) and longer than 1 hour in multiparous woman (2 hours if epidural)

66
Q

why does epidural make second stage last longer

A

can cause reduced urge to push, sensation and strong motor block (less ability to push)

can allow for passive descent in this case

67
Q

signs of non reassuring fetal status in second stage?

A

late decels

bradys

loss of variability

68
Q

what do you do with nonreassuring fetal status in second stage?

A

place mom on face mask O2

turn mom onto left to decrease IVC compression and increase uterine perfusion

discontinue oxytocin until tracing normal again

69
Q

what do you do in the setting of hypertonus (single contraction longer than 2 min) or tachysystole (more than 5 contractions in 10 min)?

A

diagnose by palpation or exam with tocometer

can give dose of terbutaline to help relax uterus

70
Q

what do you do with your hands during delivery of the head

A

one hand supports perineum and one keeps the head in flexion

71
Q

what is the first thing you do once the head is delivered

A

check for nuchal cord –> if present, reduce over the head

72
Q

what do you do once the head is delivery and nuchal cord checked?

A

direct downward pressure to allow delivery of anterior shoulder then direct upward pressure to allow delivery of the posterior shoulder

73
Q

define episiotomy

A

incision made in the perineum to facilitate delivery

74
Q

indications for episiotomy

A

need to hasten delivery

impending on ongoing shoulder dystocia

75
Q

relative contraindication for episiotomy

A

assessment than there will be large perineal laceration

76
Q

what are the two types of operative vaginal delivery

A

forceps

vaccuum

77
Q

conditions necessary for safe use of forceps (same as for vacuum)

A

full cervical dilation

ruptured membranes

engaged head at at least +2 station

absolute knowledge of fetal position

no evidence of CPD

adequate anesthesia

empty bladder

EXPERIENCED OPERATOR

78
Q

possible complications from forceps

A

bruising on face and head

lacerations to fetal head, cervix or vagina and perineum

facial nerve palsy

rarely–skull fracture and/or intracranial damage

79
Q

complications from vacuum delivery

A

scalp laceration

cephalohematoma

rare–subgleal hemorrhage (neonatal emergency)

80
Q

when does placental separation occur

A

within 5-10 min of delivery of infant but up to 30 min is usually within normal limits

81
Q

why is oxytocin indicated during stage 3

A

strengthens uterine contractions and thus decreases placental delivery time and blood loss

82
Q

3 signs of placental separation

A

cord lengthening

gush of blood

uterine fundal rebound as placenta detaches

83
Q

why do we apply suprapubic pressure during stage 3

A

to prevent uterine involution or prolapse

84
Q

when do you make the diagnosis of retained placenta

A

if not delivered after 30 min

common in preterm deliveries but can also be sign of placenta accreta

85
Q

define placenta accreta

A

invaded into or beyond the endometrial stroma

86
Q

how do you manage retained placenta

A

manual extraction where hand is placed in intrauterine cavity and fingers used to shear the placenta from the surface of the uterus

if not able to completely extract manually, curretage is performed to ensure no products are retained

87
Q

define first degree laceration

A

mucosa or skin is involved

88
Q

define second degree laceration

A

extends into perineal body but not involving anal sphincter

89
Q

define third degree tear

A

extend into or completely through the anal sphincter

90
Q

define fourth degree tear

A

occurs if anal mucosa itself is entered

watch out for “buttonhole” fourth degree lacs (sphincter still intact)

91
Q

what is the most common indication for primary cesarean delivery

A

failure to progress in labour

can be caused from any of the three Ps

92
Q

other than failure to progress, what are other indications for primary cesarean delivery

A

breech presentation

transverse lie

shoulder presentation

placenta previa

placental abruption

fetal intolerance of labour

non reassuring fetal status

cord prolapse

prolonged second stage

failed operative vaginal delivery

active herpes lesions

most common overall–previous cesarean delivery

93
Q

what is required to attempt a VBAC?

A

in house OB

anesthesiologist

surgical team

informed patient consent

Keer (low transverse) or Kronig (low vertical) incision without any extensions into the cervix or upper uterine segment

94
Q

what is the greatest risk during a trial of labour after cesarean (TOLAC)

A

rupture of prior uterine scar (0.5-1% risk)

induction of labour has a higher risk for uterine rupture

95
Q

list factors that increase the chance of success of TOLAC

A

prior vaginal birth

prior VBAC

non recurring indication for prior C/S (i.e herpes, previa, breech)

presents in labour at more than 3cm dilated and more than 75% effaced

96
Q

what are factors that decrease success of TOLAC

A

prior C/S for CPD

induction of labour

97
Q

what are factors that increase the risk of uterine rupture

A

more than one prior C/S

prior classical C/S

induction of labour

  • -use of prostaglandins
  • -use of high amounts of oxytocin

time from last cesarean less than 18 mo

uterine infection at time of last C/S

98
Q

what factors decrease the risk of uterine rupture with TOLAC

A

prior vaginal birth

99
Q

list common signs of uterine rupture in the setting of TOLAC

A

abdo pain

FHR decels or brady

sudden decrease of pressure in IUPC

maternal sensation of “pop”

100
Q

what types of agents can be used in the first stage of labour to manage pain

A

narcotics or sedatives

i.e fentanyl, Nubain, Stadol

early in labour, IM morphone sulfate is commonly used to achieve patient pain relief and rest

101
Q

why should sedating meds not be used close to the time of expected delivery

A

cross the placenta and may result in a depressed infant

can also cause maternal resp depression and increased risk of aspiration

102
Q

describe the route of the pudendal nerve

A

travels just posterior to the ischial spine at its juncture with the sacrospinous ligament

103
Q

when is a pudendal block often done

A

in case of operative vaginal delivery with either forceps or vaccuum

may be combined with local infiltration of the perineum to ensure adequate analgesia

104
Q

when is local anesthetic used

A

for an episiotomy is they do not otherwise have anesthetic or for repairs of tears

105
Q

maternal/fetal indications for cesarean

A

CPD

failed induction

106
Q

maternal indications for cesarean section

A

maternal diseases–> active genital herpes, untreated HIV, cervical cancer

prior uterine surgery–> classical cesarean or full thickness myomectomy

prior uterine rupture

obstruction to birth canal–> fibroids, ovarian tumours

107
Q

fetal indications for cesarean section

A

non reassuring fetal testing–> brady, absence of variability, scalp pH of less than 7.2

cord prolapse

fetal malpresentation–> breech, transverse lie, brow

multiple gestation–> non vertex first twin, higher order multiples

fetal anomalies–> hydrocephalus, osteogenesis imperfecta

108
Q

placental indications for cesarean section

A

placenta previa

vasa previa

abruptio placentae

109
Q

how is an epidural performed

A

epidural catheter is placed in the L3-L4 interspace when the patient requires analgesia –> usually not done until labour is in active phase

once catheter placed, initial bolus of anesthetic is given and then a continuous infusion is started

epidural does not commonly remove all sensation and can actually be detrimental to the ability to push in the second stage –> however, if need C/S, can usually just bolus the epidural and this is usually enough

110
Q

how does a spinal differ from an epidural

A

similar regions anesthetized but spinal is given in a one time dose directly into the spinal canal leading to more rapid onset of anesthesia

used more commonly for C/S than vaginal

111
Q

what is a common complication of epidurals and spinals

A

maternal hypotension secondary to decreased SVR, which can lead to decreased placental perfusion and fetal brady

more serious can be maternal resp depression if anesthetic reaches high enough level to affect the diaphragmatic innervation

spinal headache due to loss of CSF is post partum complication seen in less than 1% of people

112
Q

what are the two major concerns about general anesthesia for C/S

A

risk of maternal aspiration

risk of hypoxia to mother and fetus during induction

113
Q

list common reasons for a C/S that may require general anesthesia

A

abruption

fetal brady

umbilical cord prolapse

uterine rupture

hemorrhage from placenta previa