Topics in high risk ob advanced maternal age twins vbac preterm labor
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Topics in High Risk OB Advanced maternal age, Twins, VBAC, Preterm labor PowerPoint PPT Presentation

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Topics in High Risk OB Advanced maternal age, Twins, VBAC, Preterm labor. Susan Wing Lipinski, M.D. October 16, 2013. Learning Objectives. To become familiar with non-invasive options for prenatal testing and the appropriate indications for use

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Topics in High Risk OB Advanced maternal age, Twins, VBAC, Preterm labor

Susan Wing Lipinski, M.D.

October 16, 2013

Learning Objectives

  • To become familiar with non-invasive options for prenatal testing and the appropriate indications for use

  • To become familiar with different types of twin gestations and the unique risks associated with each

  • To understand the risk and benefits associated with a trial of labor after Cesarean section

  • To become familiar with preventative treatments for preterm labor

Advanced Maternal Age

  • Age 35 years or older at anticipated date of delivery

  • Increased risk of miscarriage

  • Increased risk of trisomies – 13, 18, 21 especially

  • Increased risk of gestational diabetesand preeclampsia

  • Increased risk of stillbirth

  • Number of women delaying childbirth is increasing

    • 1970 – 1 in 100 first pregnancies to mothers over age 35 yrs

    • 2006 – 1 in 12

Non-invasive prenatal testing

  • Quad screen

  • Integrated screen

  • Cell-free DNA testing

    Invasive Prenatal testing = Amniocentesis

Quad screen

  • Developed from AFP testing into triple marker screen and now quadruple marker screening

  • First option available to those under age 35 yrs – introduced in 1984

  • SCREENING test – not diagnostic

  • Estimates risk of trisomy 13, 18,21; abdominal wall defects; neural tube defects; indirect information about placenta and risk of preeclampsia.

  • Blood draw between 15-20 weeks

    • Alpha-fetoprotein

    • hCG

    • Estriol

    • Inhibin -A

Integrated screen

  • Takes the Quad screen (2nd trimester screening) and combines with first trimester US of nuchal thickness and first trimester biochemical markers

  • Done at 11-13 weeks

  • Detection rate for Down Syndrome 94-96%

  • Biochemical markers tested

    • Free B-hCG

    • PAPP-A (pregnancy associated plasma protein A)

Cell-free DNA testing

  • Newest option available

  • Only validated in high risk patient populations

  • Can be done as early as 10 weeks up until 32 weeks

  • Several tests available – Materniti21 most widely used in this area

  • Highly accurate at identifying the following:

    • Trisomy 13, 18, 21

    • Sex chromosome aneuploidies (XXY, X0, XYY, XXX)

    • Identifying gender – important for families with X-lined diseases

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Who gets Cell-free DNA test?

  • Age over 35 years

  • Personal or family history of chromosomal abnormalities

  • Fetal ultrasound suggestive of aneuploidy

  • Positive screening test

Prevention of stillbirth

  • Unclear etiology

  • Studies do not support placental insuffiency as cause

  • Studies do show benefits of NST testing

  • OR of stillbirth compared to age 25-29 yrs

    • 35-39 yrs OR is 1.8 – 2.2

    • 40+ yrs OR is 1.8-3.3

  • When to test?

    • Start 36-38 weeks then test weekly till delivery

    • Some benefit to twice weekly testing for those over age 40 yrs

    • Some benefit to delivery at 39 weeks in those over 40 yrs.


Monozygotic vs. Dizygotic

  • Dizygotic are always Dichorionic/Diamniotic

  • Monozygotic can be any type of chorionicity/amnionicity

  • Dichorionic/Diamniotic twins

    • 85% dizygotic

    • 15% monozygotic

Embryologic development monozygotic twins


Days 1-3



Days 4-8




Days 8-13




Embyonic disc

Days 13-15

Conjoined twins

US identification of twin chorionicity

  • Best determined in first trimester

  • Absolutely necessary to know in order to determine appropriate follow up!

  • Twin peak sign -

“Heaping up” of villi into intermembrane space

Risks associated with all twin gestations

  • Preterm labor

  • Small birth weight and IUGR

  • Gestational diabetes

  • Preeclampsia, Acute fatty liver of pregnancy

  • DVT/PE

  • Cerebral palsy – 4 times that of a singleton pregnancy!

  • Increased risk of admission to NICU

    Since 1980 there has been a 65% increase in twins and 500% increase in triplets and higher-order births!

Risks unique to Mono/Di Twins

  • Twin-to-Twin transfusion syndrome (TTTS) – 10-15% of Mono/di twins

  • Twin anemia-polycythemia sequence (TAPS) – variant of TTTS with normal amniotic fluid volumes

  • Twin reversed arterial perfusion sequence (TRAP) – acardiac twin uses co-twin for perfusion. 1% of mono/di

  • Selective intrauterine growth restriction

  • Early identification of all of these results in the best outcome – this is the area where intrauterine surgery is taking off!

Twin-to-Twin Transfusion

Risks Unique to Mono/Mono twins

  • 1 in 10,000 pregnancies

  • Twin-to-Twin transfusion is less common but possible

  • Cord entanglement

    • Begins in first trimester

    • Results in up to 23% mortality in utero

Monitoring of twin pregnancies

  • All twin gestations need growth US every 4 weeks through out pregnancy

  • Monochorionic should have q2 week US from 16-28 to screen for TTTS and its variants

  • NST screening should be done in 3rd trimester on all twins

  • Monochorionic/Monoamniotic twins should be referred to tertiary care center for hospitalized monitoring in 3rd trimester

Trial of Labor after Cesarean section – the VBAC controversy

Why all the fuss?

  • 30.8% of deliveries in Iowa were C/sections last year

  • <20% of women have a VBAC

  • Serious potential risks with BOTH Cesarean delivery and VBAC

  • ACOG practice bulletin in 2004 used the following wording “immediate availability of Cesarean section.”

    • This was interpreted to mean immediate surgical availability and therefore, in-house surgeon and anesthesia

    • As a result, many smaller hospitals discontinued VBAC’s and required RLTCS

    • Wording was revised in 2010 to try to promote more VBAC’s

What the evidence shows -

  • Most maternal morbidity during a trial of labor occurs when repeat LTCS becomes necessary

  • Overall risks for maternal complications in repeat LTCS or VBAC are very low

  • For those with successful VBAC there are significant health advantages

  • Minimal difference in neonatal morbidity between elective repeat LTCS and trial of labor

  • Probability of successful VBAC is 60-80%

  • Risks for VBAC after 2 Cesarean deliveries is only minimally increased

What do we do with this info?

  • Counsel patients about the true risks

    • There are VERY few absolute contraindications

    • Decisions should be on case-by-case basis

  • Start the conversations about VBAC/RLTCS early in pregnancy

  • Support a patient’s right to choose her delivery route

  • Respect for patient autonomy argues that even if a hospital does not “offer VBAC” you cannot force a woman to have a Cesarean delivery

Preterm labor

  • Delivery between 20 0/7 weeks to 36 6/7 weeks

  • In 2010 12% of infants were born before 37 completed weeks

  • Risks associated with preterm birth follow the child into early childhood

  • Greatest predictor is history of a prior preterm birth

Options for prevention

  • Progesterone supplementation from 16-36 weeks

    • Vaginal – Progesterone suppositories 100-200 mg nightly

    • IM injection – Makena and compounded 17 HP weekly

    • No proven benefit in twin gestation

    • Should be offered to EVERYONE with history of spontaneous preterm birth

  • Cerclage

    • Controversial

    • No proven benefit in twin gestation

Following up a history of Preterm labor

  • Start with counselling at first OB visit

  • Look for preventable causes such as STD’s, UTI’s, smoking, substance abuse, low body weight (BMI<19)

  • Offer Progesterone therapy

  • Ultrasound for cervical length q 2 weeks from 16-23 weeks

    • If cervical length 25-29 mm then move to weekly US

    • If cervical length <25 mm then refer for possible cerclage placement


  • ACOG Practice Bulletin #77 – Screening for Fetal Chromosomal Abnormalities

  • Reddy et. al. Maternal age and the risk of stillbirth throughout pregnancy in the United States. Am J Obstet Gyn. 195: 764-770. (2006)

  • Bahtiyar et. al. Stillbirth at term in women of advanced maternal age in the United States: when could the antenatal testing be initiated? Am J. Perinatology. 25(5): 301-304. (2008)

  • ACOG Practice Bulletin #56 – Multiple Gestation: Complicated twin, triplet, and high-order multifetal pregnancy

  • Uptodate – Monoamniotic twin pregnancy

  • Uptodate – Twin pregnancy: Prenatal issues

  • ACOG Practice Bulletin #115 – Vaginal birth after previous Cesarean Delivery

  • ACOG Practice Bulletin #130 – Prediction and Prevention of Preterm birth

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