PB#107: Induction of Labor Flashcards

1
Q

Physiologic goal of cervical ripening

A

Facilitate process of cervical softening/thinning/dilating

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2
Q

Clinical goals of cervical ripening (2)

A

Reduction in rate of failed IOL, reduction in IOL-to-delivery time

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3
Q

Observed histologic changes during cervical ripening (4)

A

Collagen breakdown/rearrangement, changes in glycosaminoglycans, increased cytokine production, WBC infiltration

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4
Q

Bishop score signifying unfavorable cervix

A

6 or less

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5
Q

Bishop score signifying favorable cervix

A

8 or more

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6
Q

What a “favorable” cervix indicates

A

Probability of vaginal delivery after IOL is similar to spontaneous labor

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7
Q

Bishop score points for dilation

A

Closed = 0; 1-cm = 1; 3-4cm = 2, 5-6cm = 3

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8
Q

Bishop score points for position

A

Post = 0; mid = 1; ant = 2

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9
Q

Bishop score points for effacement

A

0-30% = 0; 40-50% = 1; 60-70% = 2; 80+% = 3

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10
Q

Bishop score points for station

A

-3 = 0; -2 = 1; -1–0 = 2; +1 or more = 3

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11
Q

Bishop score points for consistency

A

Firm = 0; med = 1; soft = 2

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12
Q

General categories for cervical ripening methods (3)

A

Mechanical dilators, synthetic PGE1, synthetic PGE2

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13
Q

Mechanical cervical ripening options (5)

A

Hygroscopic dilators, osmotic dilators (Laminaria japonicum), Foley catheters, double balloon devices, EASI balloon

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14
Q

Typical size and inflation volume of cervical Foley balloon

A

14-26F, 30-80mL

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15
Q

Routes of administration of miso (3); incremental dosages of miso

A

Vaginal, PO, sublingual; 25mcg increments

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16
Q

Is intrapartum miso exposure associated w/ long-term adverse fetal consequences?

A

No (in absence of fetal distress)

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17
Q

Available formulations and dosages of PGE2 (2)

A

2.5mL syringe containing 0.5mg dinoprostone gel, 10mg dinoprostone vaginal insert

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18
Q

Which formulation of PGE2 releases prostaglandins at a slower rate?

A

Insert (0.3mg/h) over gel

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19
Q

Effect of vaginal prostaglandins for cervical ripening compared to placebo or pit alone on time to delivery; effect on C/S rate; effect on tachysystole

A

Increase likelihood of delivery within 24h; do not reduce C/S rate; increase risk of tachysystole w/ associated FHR changes

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20
Q

Time from pit onset to uterine response; time of pit onset to steady level in plasma

A

3-5 mins; 40 mins

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21
Q

Changes in response to pit by gestational age

A

Gradual increase from 20-30wga, followed by plateau from 34wga until term, then further increase in sensitivity

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22
Q

Predictors for successful response to pit IOL (4)

A

Lower BMI, greater cervical dilation, higher parity, greater EGA

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23
Q

Cytokines increases associated w/ membrane stripping (2)

A

Increase in phospholipase A2 activity, increase in PGF2alpha levels

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24
Q

Clinical benefits of membrane stripping (2)

A

Increases likelihood of spontaneous labor within 48h, reduces incidence of IOL w/ other methods

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25
Q

Risk associated w/ membrane stripping

A

Increased risk of PROM

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26
Q

Disadvantage of AROM when used alone for IOL

A

Can be associated w/ unpredictable and sometimes long intervals before onset of ctxs

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27
Q

Only “natural” method for IOL

A

Nipple/Unilateral breast stim

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28
Q

Clinical advantage of nipple stim; caveat

A

Associated w/ significant decrease in pts not in labor at 72h; only in pts w/ favorable cervices

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29
Q

Percentage of pts doing nipple stim who experienced tachysystole w/ or w/o FHR changes

A

0%

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30
Q

Does nipple stim increase or decrease mec-stained fluid; C/S rates?

A

No change; no change

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31
Q

PP benefit of breast stim for IOL

A

Decrease in PPH rates

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32
Q

How to quantify ctxs

A

Number present in 10-min window, averaged over 30-min period

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33
Q

Normal ctx rate

A

5 or fewer ctxs in 10 mins, averaged over 30-min period

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34
Q

Tachysystole

A

> 5 ctxs in 10 mins, averaged over 30-min period

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35
Q

How to qualify tachysystole

A

Presence or absence of decels

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36
Q

Does tachysystole apply to spontaneous or stimulated labor, or both?

A

Both

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37
Q

Logistical reasons for IOL (3)

A

Risk of rapid labor, distance from hospital, psychosocial indications

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38
Q

Methods to confirm gestational age for logistical IOL (3)

A

US measurement at <20wga supports age of 39+wga, FHT documented as present for 30+ weeks, positive serum/urine hCG pregnancy test 36+ weeks ago

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39
Q

General contraindications to IOL

A

The same as for spontaneous labor

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40
Q

Examples of contraindications to IOL (7)

A

Vasa previa, complete placenta previa, transverse lie, cord prolapse, hx classical C/S, active genital HSV, hx myo entering endometrial cavity

41
Q

Risk of C/S for nulliparous pts undergoing IOL w/ unfavorable cervices

A

Twofold increased risk

42
Q

Criteria prior to diagnosing failed IOL in order to reduce risk of C/S

A

At least 12-18h latent labor

43
Q

Requirements prior to cervical ripening and IOL (4)

A

Assessment of cervix, maternal pelvis, EFW, fetal presentation

44
Q

Clinical benefits of cervical balloon prior to pit (2)

A

Significantly reduced duration of labor, reduced risk of C/S

45
Q

Does addition of pit along w/ cervical balloon shorten time to delivery?

A

No

46
Q

Disadvantage of prostaglandin ripening agents compared to cervical balloon

A

Increased risk of tachysystole w/ or w/o FHT changes

47
Q

Effectiveness of vaginal miso compared to dinoprostone gel

A

Superior to or as effective as

48
Q

Clinical benefits of vaginal miso compared to dinoprostone and pit (2)

A

Less epidural use, more vaginal deliveries within 24h

49
Q

Clinical disadvantage of vaginal miso compared to dinoprostone and pit

A

More tachysystole w/ or w/o FHT changes

50
Q

Do pharmacologic methods for cervical ripening decrease likelihood of C/S?

A

No

51
Q

Typical initial cervical ripening miso dose/frequency

A

25mcg q3-6h

52
Q

Soonest pit can be administered after last miso dose

A

4h

53
Q

When can second dose of intracervical dinoprostone be given if inadequate cervical change and minimal uterine activity?

A

6-12h after first dose

54
Q

Soonest pit can be given after cervical (1.5mg) dinoprostone or vaginal (2.5mg) dinoprostone, and why?

A

6-12h, because effect of prostaglandins may be higher w/ pit

55
Q

Soonest pit can be given after sustained-release dinoprostone is removed

A

30-60 mins

56
Q

When should C/S be considered w/ miso use?

A

If tachysystole + Cat 3 FHT and no response to routine corrective measures

57
Q

Med that can be used to correct Cat 3 FHT and/or tachysystole

A

SubQ terb

58
Q

Pts for whom miso should be avoided in 3rd tri, and why

A

Pts w/ prior C/S or major uterine surgery, because of increased risk of uterine rupture

59
Q

Fetal outcome associated w/ miso use

A

Increase in mec-stained amniotic fluid

60
Q

Rate of tachysystole w/ associated FHT changes seen in intracervical dinoprostone 0.5mg gel

A

1%

61
Q

Rate of tachysystole w/ associated FHT changes seen in intravaginal dinsoprostone 2-5mg gel or vaginal insert

A

5%

62
Q

Typical timing of onset of tachysystole s/p dinoprostone gel/insert placement

A

1h (but may occur up to 9.5h after)

63
Q

Method to help reverse effects of tachysystole associated w/ dinoprostone vaginal insert

A

Removal of insert (irrigation of cervix/vagina is not beneficial)

64
Q

Common maternal side effects assocaited w/ low-dose dinoprostone (3)

A

Fever, vomiting, diarrhea

65
Q

Pts in whom caution should be exercised w/ dinoprostone use (3)

A

Glaucoma, severe hepatic/renal dysfunction, asthma

66
Q

Clinical disadvantage of Laminaria japonicum/hygroscopic dilators over dinoprostone analogs

A

Increased maternal/neonatal infections

67
Q

Clinical risks associated w/ cervical balloon (4)

A

Significant VB in pts w/ low-lying placenta, ROM, febrile morbidity, displacement of presenting part

68
Q

Positioning rec after prostaglandin placement

A

Pt should remain recumbent x30 mins

69
Q

Fetal surveillance s/p dinoprostone gel placement

A

FHT/TOCO monitoring continuously x30 mins-2h

70
Q

When are ctxs usually first seen, and when do they exhibit peak activity, following prostaglandin placement?

A

Within first hour, in first 4 hours

71
Q

Pts for whom outpatient dinoprostone gel is safe and effective for IOL

A

Term pts w/ Bishop score 6 or less

72
Q

By how much time does outpatient cervical balloon reduce hospital stay?

A

9.6h

73
Q

Most common adverse effects of pit (2)

A

Tachysystole, Cat 2-3 FHT (typically dose-dependent)

74
Q

Potential catastrophic effects of tachysystole (2)

A

Abruption, uterine rupture (rare, even in parous pts)

75
Q

Rare risk that occur w/ high concentrations of pit infused w/ large quantities of hypotonic solutions

A

Water intoxication

76
Q

Which route of miso produces greater clinical efficacy at equivalent dosage?

A

Vaginal (over PO)

77
Q

Benefits of PO miso administration over vaginal (2)

A

Fewer abnormal FHT patterns, fewer episodes of tachysystole w/ associated FHT changes

78
Q

Does tachysystole w/o decels portend any significant increase in adverse fetal outcomes?

A

No

79
Q

Potential risks associated w/ AROM (4)

A

Cord prolapse, chorio, significant cord compression, rupture of vasa previa

80
Q

Precautionary measures to take at time of AROM (3)

A

Palpate for cord, avoid dislodging fetal head, FHT assessed before and immediately after AROM

81
Q

Pts in whom AROM is contraindicated, and why

A

HIV+ pts, since duration of ROM has been identified as independent risk factor for vertical HIV transmission

82
Q

Risks associated w/ membrane stripping (2)

A

Bleeding (if undiagnosed placenta previa/low-lying placenta), accidental AROM

83
Q

Risk associated w/ bilateral nipple stim

A

Tachysystole w/ associated decels

84
Q

Pit regimens/management strategies that are associated w/ decreased tachysystole w/ associated FHT changes

A

Low-dose regimens/less frequent increases in dose

85
Q

Clinical benefits of high-dose pit regimens/more frequent dose increases (3)

A

Shorter labor, less frequent cases of chorio, less frequent cases of C/S for labor dystocia

86
Q

What is max dose of recommended pit?

A

Not established

87
Q

Example of low-dose pit regimen

A

0.5-2mU/min starting dose > increase 1-2mU/min q15-40 mins

88
Q

Example of high-dose pit regimen

A

6mU/min starting dose > increase 3-6mU/min q15-40 mins

89
Q

Initial management strategies for tachysystole w/ Cat III FHT (3)

A

Decrease/discontinue pit, turn pt on side, IVF resuscitation if hypotensive, supplemental O2 if hypoxic

90
Q

Management strategy for persistent tachysystole despite initial measures

A

Terb

91
Q

Clinical benefits to pit IOL for PROM pts (4), w/o increasing rate of C/S or neonatal infections

A

Reduce time interval between PROM and delivery, decrease frequency of IAI, decrease frequency of PP febrile morbidity, decrease frequency of neonatal abx txs

92
Q

When should pts w/ term PROM be induced w/ pit, and why?

A

At time of presentation, in order to reduce risk of IAI and NICU admissions

93
Q

Does use of miso/dinoprostone increase risk of infection in pts w/ PROM?

A

No

94
Q

When can D&E be offered to pts w/ IUFD?

A

In 2nd tri if experienced provider is available (though D&E may limit efficacy of autopsy)

95
Q

When is IOL appropriate for pts w/ IUFD (3)?

A

At later gestational ages, if 2nd tri D&E unavailable, per pt preference

96
Q

When should vaginal miso be recommended for IOL in pts w/ IUFD?

A

Use in nonviable pregnancies at <24wga, recommend for IUFD pregnancies at <28wga (regardless of Bishop score) though high-dose pit is an acceptable alternative

97
Q

Typical dosing protocol for vaginal miso in pts w/ IUFD

A

200-400mcg q4-12h

98
Q

Preferred option for pts w/ IUFD w/ prior LTCS and <28wga

A

VTOL w/ miso at 400mcg q6h (because no increased risk of uterine rupture/complication)

99
Q

Additional ripening option for pts >28wga w/ IUFD and unfavorable cervices

A

Cervical balloon