2 Sun 945 - Stone Timing of delivery · Increase in LP birth per state Almost all stated had an INCREASE in Late Preterm births Late preterm births by plurality: % of live births

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Timing of Delivery

Joanne Stone, MDProfessor, Obstetrics, Gynecology and Reproductive 

SciencesIcahn School of Medicine at Mount Sinai

Director, Maternal Fetal Medicine Health System

Objectives

• Illustrate the risks of delivery prior to 39 weeks

• Describe what is considered a non‐elective (medically indicated) vs. elective delivery prior to 39 weeks 

• Determine when delivery prior to 39 weeks is indicated

Disclosures

• I have no disclosures to submit

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Frequency of adverse neonatal outcomes 

• Term (traditionally): 37 – 42 weeks

• LOWEST RISK: 39 + 0 to 40 + 6 weeks gestation

• Large focus on decreasing non‐medically indicated deliveries < 39 weeks

Recommended Classification of Deliveries from 37 weeks of gestation

• Early term: 37 0/7 – 38 6/7 weeks

• Full term: 39 0/7 – 40 6/7 weeks

• Late term: 41 0/7 – 41 6/7 weeks

• Post‐term: 42 0/7 weeks and beyond

ACOG Committee Opinion No. 579 Nov 2013

Looking at Late Preterm Births:Changing Distribution of US Live Births:

1992, 1997, 2002

0%

5%

10%

15%

20%

25%

30%

28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44

Gestational Age (weeks)

Per

cen

t

1992 1997 2002

Peak Shifted: 40 to 39 weeks

Source: NCHS, final natality dataPrepared by March of Dimes Perinatal Data Center, April 2006.

Late preterm deliveries shifted:34 – 36 6/7 weeks

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Increase in LP birth per state

Almost all stated had an INCREASE in Late Preterm births

Late preterm births by plurality:% of live births

singletonsmultiples

0

10

20

30

40

1997 1998 1999 2000 2001 2002

singletons

multiples

34.6 38.1

7.2

8.0

Peristats, March of Dimes, 2007

Neonatal and Infant Mortality Rates (2001):Deaths per 1000 Births

Gestational age (weeks)

Neonatal Mortality Rate

RR (95% CI) Infant Mortality Rate

RR (95% CI)

34* 7.1 9.5 (8.4‐10.8) 11.8 5.4 (4.9‐5.9)

35* 4.8 6.4 (5.6‐7.2) 8.6 3.9 (3.6‐4.3)

36* 2.8 3.7 (3.3‐4.2) 5.7 2.6 (2.4‐2.8)

37* 1.7 2.3 (2.1‐2.6) 4.1 1.9 (1.8‐2.0)

38* 1.0 1.4 (1.3‐1.5) 2.7 1.2 (1.2‐1.3)

39 0.8 1.00 (reference)

2.2 1.00 (reference)

40 0.8 1.0 (0.9‐1.1) 2.1 0.9 (0.9‐1.0)

*p<0.001 Reddy UM, Ko C, Raju TNK, Willinger M. Pediatrics 2009;124:234‐240

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Not All Respiratory Distress in Late Preterm Infants is Benign

0

2000

4000

6000

8000

10000

12000

14000

23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40

Estimated Gestational Age (wks)

Nu

mb

er

of

Pa

tien

ts

CPAP Oxygen Nasal cannula HFV Ventilator

Clark R et.al, Pediatrx Database, 2005Slide courtesy of Dr. Gyamfi-Bannerman

First year costs by type of service among late‐preterm and term infants

McLaurin K et al Peds 2009

What About Long Term Outcomes?

• White and gray matter follow different rates of maturation with only 65% of term brain volume at 34 wks(Billiards SS et al Clin Perinatol 33:915, 2006)

• Late Preterm infants (33 -37 weeks) account for 74% of adult disability in Sweden at 23-29 yrs age (n=522,310)(Lindstrom K et al Pediatr 120:70,2007)

Slide courtesy of Gyamfi‐Bannerman

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What about early term births?

Reduce “early‐term” birthsDecrease number of non‐indicated deliveries < 39 weeks

Elective Cesarean Delivery at Term

• Secondary analysis of MFMU Cesarean Registry– Prospective observational study 1999-2002

• Elective singleton cesarean deliveries at term (≥37 wks) at 19 medical centers– Elective deliveries: absence of labor or medical/obstetric

indication• Primary outcome composite:

– neonatal death, RDS or TTN, hypoglycemia, newborn sepsis, NEC, HIE, need for CPR or ventilation within 24 hours, pH <7, 5 min Apgar <3, NICU admission, and prolonged hospitalization

Tita A, et al. N Engl J Med 2009;360:111‐20

Elective Cesarean Delivery: Results

• 13,258 elective singleton repeat cesarean deliveries

• Range of GA ≥37 wks to 42+ wks

• 35.8% of elective deliveries were <39 weeks– 6.3% at 37 wks

– 29.5% at 38 wks

Tita A, et al. N Engl J Med 2009;360:111‐20

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Timing of Repeat Cesarean and Primary Outcome

Tita A, et al. N Engl J Med 2009;360:111‐20

Adverse Neonatal Outcomes According To Completed Week of Gestation at Delivery

13,258 Elective RCS from 19 Hospitals

Tita A, et al. N Engl J Med 2009;360:111‐20

Spontaneous(PTL, PPROM)

Indicated(NRFHT, severe

preeclampsia/HELLP, abruption, previa,

Repeat C/S, IUGR w/ normal testing)

Elective

277/514 155/514 42/514

53.9% 37.9% 8.2%

Holland M et al, AJOG. 2009;201:404.e1-4

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Spontaneous(PTL, PPROM)

Indicated(NRFHT, severe

preeclampsia/HELLP, abruption, previa)

Elective (Repeat C/S,

IUGR w/ normal testing, oligo, multiples)

1821/2693 378/2693 494/2693

67.6% 14.0% 18.3%

Gyamfi-Bannerman et al, AJOG. 2011;205:456.e1-6

But is early birth really all bad?

Prevents fetal death Reduces exposure of fetus to potentially hostile

intrauterine environment

Balancing risks of continuing pregnancy vs risk of delivery before term

Spong et al Obstet Gynecol 2011

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Decrease in stillbirths in singleton PTBs

Ananth CV et al Obstet Gynecol 2005;105:1084-91

Stil

lbirt

hs (

/1,0

00 b

irths

)

1989 1991 1993 1995 1997 1999 2001

403632

28

24

20

12

16PPROM

SPTB

TotalMedicallyIndicated

So when is Late‐Preterm and Early Term Birth Indicated?

Obstet Gynecol 2011;118:323-333

Based on NICHD and SMFM workshop 2011Focused on 3 areas:‐placental/uterine‐fetal‐maternal conditions

Placental Previa and Placenta Accreta:

Risk of continued pregnancy: Obstetric hemorrhage/labor

Transfusion

Admission to ICU

Fetal/neonatal hypoxemia/acidemia from maternal hypovolemic shock

Maternal death

Placenta previa Placenta accreta

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Potential benefits of iatrogenic late PTB in women with placenta previa

• Decreased probability of c/s with an unstable patient– Avoid hemorrhage, anemia, sick

– Avoid fetal compromise

– Avoide c/s under emergent circumstances

• Optimize availability of hospital resources– OR resources (surgeons, anesthesia)

– Blood bank and blood products

– Consultants

Blackwell, SC Seminars in Perinatology 2011

Balancing risks of maternal and fetal/neonatal complications

4.7

15

29.9

58.6

87.2

42.4

22.1

11.8

7.2 6.14.5 31.1 0.5 0.30.4 0.3 0.2 0.1 0.1

‐2

8

18

28

38

48

58

68

78

88

35 weeks 36 weeks 37 weeks 38 weeks 39 weeks

mat'l  emerg bleed

NICU admission

neon mech vent

neonat mortaliity

Zlatnik et al J Mat Fet Neo Med 2007Zlatnik et al J ReprodMed 2010

Hibbard  et al JAMA 2010

When to deliver placenta previa?

ACOG and SMFM: deliver at 36 0/7 – 37 6/7** without documentation of fetal lung maturity*

*Uncomplicated, thus no FGR, superimposed PE, etc; in these situations earlier delivery may be indicated**GA in completed weeks, “36 weeks” includes 36 weeks and 0 days through 36 weeks and 6 days

Decision analysis (Zlatnik et al J Repro Med 2010): antenatal steroids 35+5 weeks and delivery at 36 weeks

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When to deliver placenta previa with suspected accreta, increta, percreta?

Deliver at 34 0/7 – 35 6/7

Consider earlier delivery (34 weeks) in setting ofrecurrent vaginal bleeding,PPROM or uterine contractions  Bowman et al AJOG 2014

Placenta accreta: 44% will require emergency surgery if delivery planned >36 wks

Prior classical CD, myomectomy

•Incidence uterine rupture: 0.3% of pregnancies with prior upper segment uterine incision

•Prior myomectomy: CD often recommended if muscular portion of myometrium involved

Risk of continued pregnancy:

Uterine rupture with hemorrhage, shock, transfusion, stillbirth,

fetal/neonatal hypoxia/acidosis

Audience response

• At what gestational age is cesarean delivery for women with a prior myomectomy (where CD is indicated)?– A. 34‐35 weeks– B. 35‐36 weeks– C. 36‐37 weeks– D. 37‐38 weeks– E. 38‐39 weeks

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Timing of delivery for prior classical CD and myomectomy

• Prior classical*

• Prior myomectomy where CD is recommended*

*Uncomplicated, thus no FGR, superimposed PE, etc; in these situations earlier delivery may be indicated**GA in completed weeks, “36 weeks” includes 36 weeks and 0 days through 36 weeks and 6 days

36-37 weeks

37-38 weeks

Correct answer is D!!

Fetal Growth Restriction

• GRIT (Growth Restriction Intervention Trial)

– Randomized patients 24‐36 weeks to immediate or delayed delivery if OB uncertain

– Early delivery to avoid stillbirth counterbalanced by neonatal/infant deaths – esp if < 31 weeks

DIGITAT (Disproportionate Intrauterine Growth Intervention Trial at Term)

Randomized pts > 36 weeks to IOL vs expectant mgmtSimilar composite adverse outcomes (6.1% vs. 5.3%)

Indicated Late Preterm and Early Term Births: Fetal Growth Restriction

0%

5%

10%

15%

20%

25%

34 35 36 37 38 39 40 41 42Gestational Age (weeks)

Per

cent

Expeditious delivery regardless of gestational age Persistent abnormal fetal surveillance 

suggesting imminent fetal jeopardy

Complicated34 0/7-37 6/7 weeks

Uncomplicated38 0/7-39 6/7

weeks

Courtesy of Dr. Gyamfi‐Bannerman

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Twins

• Risk of continued pregnancy

– Maternal (preeclampsia)

– Fetal (stillbirth, IUGR)

• Chorionicity and amnionicity play important role

Audience response

• When is it best to deliver uncomplicated monochorionic diamniotic twins?

– A. 32 weeks

– B. 32‐34 6/7 weeks

– C. 34 weeks

– D. 34 – 36 6/7 weeks

– E. 34 – 37 6/7 weeks

Timing of delivery for twins

Type twins Suggested timing of delivery

Uncomplicated dichorionic diamniotic 38 0/7 ‐ 38 6/7 weeks*

Uncomplicated monochorionic‐diamniotic 34 0/7 – 37 6/7 weeks* (most 36)

Di‐Di with isolated FGR 36 0/7 – 37 6/7 weeks*

Di‐Di with other condition (abn. Dopplers, maternal co‐morbidity)

32 0/7 – 34 6/7 weeks*

Mo‐Di with isolated FGR 32 0/7 – 34 6/7 weeks*

Mono‐mono 32 weeks?

Death of one co‐twin Case by case basis

*ACOG recommendations

Answer E

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Preeclampsia and Gestational Hypertension

• Risk of continued pregnancy:– Development of severe PE or

severe GHTN and its complications, fetal complications (FGR, asphyxia, abruption, stillbirth)

Hypertension & PreeclampsiaACOG/SMFM recommendations

• cHTN – no medications*

*Uncomplicated, thus no FGR, superimposed PE, etc; when earlier delivery may be indicated**GA in completed weeks, “36 weeks” includes 36 wks and 0 days through 36 wks 6 days

cHTN – controlled on meds*

cHTN – difficult to control (multiple adjustments)* 36-37 6/7 weeks

Gestational HTN*

Preeclampsia - mild* 37 weeks

At diagnosis (>34wks) Preeclampsia - severe*

38-39 0/7 weeks

37-39 6/7 weeks

37-38 6/7 weeks

Prior Stillbirth•Incidence:

– SB in 5-12/1000 live births

– Recurrence of SB: up to 8%

•Risk of continued pregnancy: – Recurrent stillbirth, FGR, preeclampsia, maternal

anxiety

*Uncomplicated, thus no FGR, superimposed PE, etc; when earlier delivery may be indicated

Timing of Delivery with current pregnancy uncomplicated*:

LPTB/ET not recommended

Consider amniocentesis if delivered at <37-38 wks

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Intrahepatic cholestasis of pregnancy

• Balance risk of fetal death and risk of prematurity• Deliver at 36 – 36/7 weeks w/o FLM amnio

– Retrospective cohort study to determine risk of PNM (stillbirth + infant death) with delivery vs. expectant mgmt stratified by week

– 36 weeks best• fetal, neonatal or infant mortality 4.7/10,000 vs mortality with expectant mgmt 19.2/10,000 

• Delivery prior to 36 weeks?• Unremitting pruritis• Jaundice• Prior fetal demise < 36‐37 weeks due to ICP with recurring ICP• ?total serum bile acid >/= 100 micromol/L

Pujic et al AJOG 2015:212(5)667.e1

Preterm premature rupture of the membranes (PPROM)

•Risk of continued pregnancy: – Stillbirth, chorioamnionitis

• PPROMEXIL trial and meta-analysis: IOL vsexp mgmt: IOL did not improve outcome 34-37 weeks

PPROM*

*Uncomplicated, thus no FGR, superimposed PE, etc; when earlier delivery may be indicated

Timing of Delivery

34 weeks

Spontaneous PTL* Deliver for progressive PTL

GDMA1?

• Paucity of literature:

– 4 cohort studies and 1 RCT (GDMA2 on insulin)

• RCT suggested better outcome with delivery at 38 weeks

• Cohort studies didn’t differentiate A2 or A1

– Decision analysis found best outcome with delivery at 38 weeks

• ACOG/SMFM do not recommend delivery < 39 weeks

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Advanced maternal age?

No studies on surveillance or optimal deliveryMost say NOT < 39 weeks

When to delivery early term?

Indicated early term

37-38 weeks

• Mild preeclampsia

• Poorly controlled diabetes

• IUGR

• Prior myomectomy

• Dichorionic, diamniotictwins

• Certain congenital anomalies

Non‐indicated early term

• Well controlled A1 or A2 gestational diabetes

• Well controlled pregestational diabetes

• Prior unexplained IUFD

Spong C et al, Obstet Gynecol. 2011;118:323-33

Late term/early term:when is the right time to

deliver?

• With the drive to reduce deliveries < 39 wks and public health awareness of PTB, it is important to realize some early deliveries benefit mother, baby or both

• Certain conditions optimally deliver in late preterm

• List not all inclusive (obesity,vasa previa) • Informed decision making, individualization

based on cormorbidities and counseling are critical

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Thank you!!