Overdue and out of juice: post dates monitoring and

oligohydramniosGerry Marquette

Maternal Fetal MedicineBC Women’s Hospital

23rd Obstetrics Update for FPVancouver, October 2011

Objectives

• How we define overdue• When to start monitoring• How amniotic volumes are

measured and interpreted

Always use the proper name for things. Fear of a name increases fear of the thing itself.

Professor Albus Dumbledore,

to Harry Potter

Overdue

• Postterm: beyond 41 6/7 weeks or 293 days from LMP

• Postmaturity: dysmaturity (=IUGR in the term fetus)

• Post term= Prolonged pregnancy= post dates

Stillbirth rate in BC 2000-2009

0.0

1.0

2.0

3.0

4.0

5.0

6.0

2000 2001 2002 2003 2004 2005 2006 2007 2008 2009

Gestational age (weeks)

Stillbirths per 1,000

 total births

Risk of stillbirth in BC

0.00.20.40.60.81.01.21.41.61.82.0

28 29 30 31 32 33 34 35 36 37 38 39 40 41 >=42

Gestational age (weeks)

Stillbirths per 1,000

 fetuses a

t risk

Postterm morbidity

• Macrosomia/birth trauma• Meconium aspiration/NICU admission• Low Apgar/pH

Fetal/Neonatal

Maternal

C/S or assisted delivery

Increase in births at 41 weeks

• Decrease in births at 42 weeks• Increase in births at 41 weeks

When to start monitoring20 studies

Induction vs monitoring

• 41, 41 2/7,41 3/7, 42 weeks• Different methods of estimating gestational

age• Outcomes: perinatal mortality, morbidity

Canadian multi centre trialN=3407

Induction Monitor p OR

FetalDistress

10.3 % 12.8 % 0.017

Meconium 25 % 28.7 % 0.009

C/S 21.2 % 24.5 % 0.03 1.22 with CI=1.02-1.45

No diff in PNM and NN morbidityHannah M, N Engl J Med 1992;326:1587–92

Metaanalysis of prospective studies n=6588

Induce Monitor OR/CIC/S 20.1% 22% 0.88

0.78-0.99C/SAbn FHR

6.2% 8.0% 0.770.61-0.96

MeconiumStaining

22.4% 27.7% 0.750.66-0.84

Sanchez-Ramos Obstet Gynecol 2003;101:1312–8.

No diff in PNM and NN morbidity

Cochrane Metaanalysis of prospective studies n=5939

Induce Monitor RR/CIPNM 1/2986 9/2953 0.3

0.09-0.99C/S 23% 24.8% 0.92

0.76-1.12Meconiumaspiration

0.290.12-0.68

Cochrane Database Syst Rev 2006 Oct 18;(4):CD004945.

No diff in NN morbidity

Type and frequency of testing

• NST, BPP, CST, Doppler, AFV• Only one RCT on type • RCT’s on induction vs monitoring:

start during week 41more than once a weekNST and AFI

RCT: method of fetal surveillance145 uncomplicated pts at 42 weeks• 1.Modified BPP: computerised CTG, AFI,

breathing, gross and fine mvts vs 2.NST/DVP

• Abn results 1= 45%• Abn results 2= 20%

OR 3.5; 99% CI 1.3–9.1 no diff in outcomes

• Abn AFV 1 vs 2: 44.4% vs. 15.1%: OR 4.5; 99% CI 1.6–12.8Alfirevic et al. Br J Obstet Gynaecol 1995;102:638–43.

Amniotic fluid assessmentPostterm BCWH

• Normal: 5-95 percentile• Moderate oligohydramnios: 2.5-5 perc• Severe oligohydramnios: <2.5 perc

Amniotic fluid assessmentPostterm BCWH

AFI and DVP

• Normal: AFI≥50 and DVP≥20• Moderate oligo: AFI<50 and DVP≥20• Severe oligo: DVP<20

Reducing pregnancies reaching 41 weeks

• Early scan• Membrane sweeping

RCT first vs second trimester u/s dating

First trimester U/SN=104

Second trimester U/SN=92

p RRCI

Redated41.3% 10.9% <0.001

0.260.15-0.46

Induction for postterm

5/104 12/92 0.01 0.370.14-0.96

Bennett at al AJOG 2004;190;1077

Postterm protocolBCWH

• Induction offered as of 41 3/7 weeks but no later than 42 weeks

• Fetal surveillance as of 41 weeksevery 3 days

• NST and AFI/DVP

Postterm protocolBCWH

• If NST and AFV are normal: repeat testing within 3 days

• If NST is atypical or abnormal, furthur monitoring done immediately following U/S (Doppler of UA added)

• If moderate oligo: offer induction or repeat testing within 2 days (Doppler added)

• If severe oligo present: delivery is highly suggested

Conclusion

• How we define overdue• When to start monitoring• How amniotic volumes are

measured and interpreted

Postterm protocolBCWH

NST/AFV normal:Repeat testing within 3 days

If NST Is atypical/abnormal:

Doppler addedImmediate furthur

monitoring

If moderate oligo:Doppler added

Suggest induction/delivery

Or retest within2 days

If severe oligo:Doppler added

Consider immedateInduction/delivery