Fetal Therapy Flashcards
- Improvements in all the following have been shown after in utero myelomeningocele repair EXCEPT:
A. Need for cerebrospinal fluid shunt
B. Hindbrain herniation at age 12 months
C. Ability to walk without orthotics
D. Rates of death
D. Based on the management of myelomeningocele study (MOMS) trial, there were significantly decreased rates of ventriculoperitoneal shunt at age 12 months, decreased rates of hindbrain herniation at age 12 months, and increased rates of walking independently at age 30 months. There was no significant difference in mortality between the pre- and postnatal surgery groups. These results should not be extended to all infants receiving in utero repair of myelomeningocele. The trial took place with experienced surgeons, multidisciplinary teams, and stringent follow-up. Women who were included also had to meet strict criteria, including myelomeningocele between T1 – S1, hindbrain herniation, gestational age between 19-26 weeks, no evidence of kyphosis, and maternal BMI less than 35. Ideally, women who undergo in utero repair should meet these criteria and undergo surgery at facilities with expertise and multidisciplinary teams. Risks associated with in utero repair, such as high rates of preterm birth, oligohydramnios, placental abruption, and uterine dehiscence, should not be ignored. These risks have serious implications for the current as well as future pregnancies. Patients should be counseled about both the risks and benefits of in utero repair.
- A 37 year old G2P1001 at 22 weeks and 4 days gestation by IVF dating presents for biweekly ultrasound surveillance of her known monochorionic diamniotic twin gestation. On today’s ultrasound, Twin A is noted to have a maximal vertical pocket (MVP) of 9.2 cm and twin B has an MVP of 0.8 cm. Normal fetal bladders are visible for both twins. Doppler studies are normal. There is no evidence of hydrops. YOu diagnose this pregnancy with stage I twin-twin transfusion syndrome (TTTS). What is the approximate overall perinatal survival rate for stage I TTTS without treatment?
A. 20%
B. 40%
C. 60%
D. 80%
E. 100%
D. Twin-twin transfusion syndrome complicates 8% to 10% of monochorionic diamniotic twin pregnancies. The diagnosis of TTTS is made using an ultrasound-based staging system established by Quintero et al. In this case, since the only sonographic abnormality is polyhydramnios/oligohydramnios, the diagnosis is stage 1 TTTS. Perinatal loss in cases of TTTS stage 3 and higher is between 70% to 100%. While the prognosis for advanced-stage TTTS is poor, stage 1 TTTS has a relatively good prognosis. Only 15% to 27% of cases progress to a higher stage, and the overall survival rate (a pooled rate that includes both single and double survival) is 79% to 86%. Most experts agree that expectant management with weekly ultrasound surveillance is the appropriate choice to manage twins with stage 1 TTTS. The overall survival rate for stage 1 TTTS with expectant management is 86%, reported survival after amnioreduction is 77%, and after laser photocoagulation is 86%. Therefore, most centers recommend expectant management for stage 1 TTTS. 1. Simpson LL. Twin-twin transfusion syndrome. American journal of obstetrics and gynecology 2013;208:3-18. 2.Khalil A, Cooper E, Townsend R, Thilaganathan B. Evolution of Stage 1 Twin-to-Twin Transfusion Syndrome (TTTS): Systematic Review and Meta-Analysis. Twin Res Hum Genet. 2016 Jun;19(3):207-16.
What are the Quintero stages
C.
Sonographically twin-twin transfusion syndrome (TTTS) is diagnosed when the following criteria are met: (1) the presence of a monochorionic diamniotic (MCDA) pregnancy; and (2) the presence of oligohydramnios (defined as a maximal vertical pocket [MVP] of less than 2 cm) in 1 sac, and of polyhydramnios (a MVP greater than 8 cm) in the other sac. TTTS complicates about 8–10% of MCDA pregnancies and it can occur in an MCDA twin pair with triplet or higher-order pregnancies. In part because TTTS does not progress in a predictable manner, serial sonographic evaluations approximately every 2 weeks, beginning usually around 16 weeks of gestation through delivery, should be considered for all twins with MCDA placentation. In 1999, Quintero et al. described the most commonly used TTTS staging system and it is based on sonographic findings. The system includes 5 stages:
Stage 1 – Polyhydramnios (maximal vertical fluid pocket >8 cm) in the recipient and oligohydramnios (maximal vertical fluid pocket <2 cm) in the donor.
Stage 2 – Bladder not visualized in the donor twin.
Stage 3 – Umbilical artery, middle cerebral artery, ductus venosus, or umbilical vein abnormalities in either twin.
Stage 4 – Presence of hydrops in either twin.
Stage 5 – Fetal demise of 1 or both twins.
This system has some prognostic significance and provides a method to compare outcome data using different therapeutic interventions. Although the stages do not correlate perfectly with perinatal survival, it is relatively straightforward to apply, may improve communication between patients and providers, and identifies the subset of cases most likely to benefit from treatment.
Society for Maternal-Fetal Medicine, Simpson LL. Twin-twin transfusion syndrome. Am J Obstet Gynecol. 2013;208:3-18.
Quintero RA, Morales WJ, Allen MH, et al. Staging of twin-twin transfusion syndrome. J Perinatol. 1999;19:550-555.
- A 24 year old G1P0 with monochorionic diamniotic twin gestation presents for an ultrasound assessment at 20 weeks gestation. One of the twins has a MVP 1.5 cm and the bladder is not visualized. The co-twin has an MVP 13 cm with an enlarged bladder. Umbilical artery doppler assessments are found to be within normal limits for both twins and there is no evidence of hydrops. The middle cerebral doppler peak systolic velocity is 1.1 MoM and 0.9 Mom respectively. The best next step in management is:
A. Expectant management
B. Septostomy
C. Amnioreduction
D. Laser photocoagulation
D.
Twin-Twin Transfusion Syndrome (TTTS) complicates approximately 10–15% of all monochorionic twin gestations. Left untreated, TTTS before 26 weeks gestation is associated with a high rate of fetal loss, perinatal death, and handicap in survivors. Staging for TTTS has been devised by Quintero and colleagues and includes: Stage 1 – Polyhydramnios (Maximal vertical fluid pocket >8 cm) in the recipient and oligohydramnios (maximal vertical fluid pocket <2 cm) in the donor. Stage 2 – Bladder not visualized in the donor twin. Stage 3 – Umbilical artery, middle cerebral artery, ductus venosus, or umbilical vein abnormalities in either twin. Stage 4 – Presence of hydrops in either twin. Stage 5 – Fetal demise of 1 or both twins. Recently, substaging based on fetal cardiac function has been described by Rychik and colleagues, and therefore a fetal echocardiogram is an important part of the evaluation of suspected TTTS. Given the high degree of fetal loss with expectant management of severe early onset TTTS, management options include septostomy, selective fetal reduction by cord occlusion, amnioreduction, and laser photocoagulation. For women desiring a chance of survival for both twins, the major options include amnioreduction or laser photocoagulation of the placental vessels. In the largest randomized study by Senat and colleagues, laser photocoagulation of the placental vascular connections was associated with prolonged gestational age at delivery (33 weeks vs 29 weeks) and a greater chance of survival of at least 1 twin at 28 days of life (76% vs 56%) when compared with serial amnioreductions.
Senat MV, et al. Endoscopic laser surgery versus serial amnioreduction for severe twin-to-twin transfusion syndrome. N Engl J Med. 2004;351:136-144.
Quintero RA, et al. Staging of twin-twin transfusion syndrome. J Perinatol. 1999 Dec;19(8):550-555.
Rychik J, et al. The twin-twin transfusion syndrome: spectrum of cardiovascular abnormality and development of a cardiovascular score to assess severity of disease. Am J Obstet Gynecol. 2007;197(4):392.e1-8.
A G1P0 is admitted for preterm labor at 26 weeks gestation. Which of the following is the MOST appropriate reason to administer intravenous magnesium sulfate?
A. Is is an effective tocolytic
B. It reduces the risk of cerebral palsy or death
C. It decreased cerebral palsy in survivors
D. It lowers the chance of composite neonatal and childhood morbidity (IVH, PVL, CP, and death)
B.
A link between antenatal exposure to magnesium sulfate and a reduction in cerebral palsy was first suggested in case-control studies of extremely preterm infants. Since then, 5 randomized controlled trials (n=5235) have evaluated the neuroprotective effects of antenatal exposure to magnesium sulfate. These trials compared magnesium sulfate with placebo in women at risk for early preterm delivery. In the randomized trial conducted in the US by Rouse et al., there was no difference in the primary composite outcome of stillbirth or infant death by 1 year or moderate or severe cerebral palsy at or beyond 2 years of age. However, in a prespecified secondary analysis, moderate or severe cerebral palsy occurred significantly less frequently in the magnesium sulfate group (relative risk [RR] 0.55; 95% confidence interval [CI], 0.32–0.95). In a meta-analysis of all 5 magnesium trials (n=5235), in-utero exposure to magnesium sulfate was shown to reduce the risk of cerebral palsy (RR 0.70; 95%CI 0.55–0.89), moderate-severe cerebral palsy (RR 0.60; 95%CI 0.43–0.84), and death or moderate-severe cerebral palsy (RR 0.85; 95%CI 0.73–0.99). Results were similar for analyses of births before 32–34 weeks and before 30 weeks. When the analysis was limited to the 4 neuroprotection trials (n=4324), magnesium sulfate was associated with a reduction in the combined outcome of cerebral palsy (any severity) and death (RR 0.86; 95%CI 0.75–0.99). Antenatal exposure to magnesium sulfate has not been shown to reduce the risk of composite neonatal and childhood morbidity. It has not been associated with reductions in intraventricular hemorrhage (IVH) or periventricular leukomalacia (PVL). There is no known association between antenatal magnesium sulfate and risk of neonatal encephalopathy. Magnesium sulfate has not been demonstrated to be an effective tocolytic. The most correct answer is therefore a reduction in cerebral palsy or death, which was the primary outcome in the meta-analysis of neuroprotection trials. These 2 outcomes were combined for the primary outcome because death and cerebral palsy are competing outcomes (a baby cannot go on to have cerebral palsy if it dies). The number needed to treat to prevent 1 case of cerebral palsy among survivors is 46 for those exposed before 30 weeks gestation, and 56 for those exposed before 32–34 weeks. Although the neuroprotective role of magnesium sulfate is now well established, the mechanism of fetal neuroprotection remains uncertain. It is hypothesized that it may work via (1) promotion of vascular stability, (2) prevention of hypoxic-ischemic reperfusion injury, (3) reduction in excitatory amino acid damage by acting as a noncompetitive N-methyl-D-aspartic acid (NMDA) receptor antagonist, and/or (4) mitigation of cytokine-mediated inflammatory injury.
Costantine MM, Weiner SJ. Effects of antenatal exposure to magnesium sulfate on neuroprotection and mortality in preterm infants: a meta-analysis. Obstet Gynecol. 2009;114(2 Pt 1):354-364.
Rouse DJ, et al. A randomized, controlled trial of magnesium sulfate for the prevention of cerebral palsy. N Engl J Med. 2008;359(9): 895-905.
American Congress of Obstetricians and Gynecologists, Committee Opinion #455, March 2010, “Magnesium Sulfate Before Anticipated Preterm Birth for Neuroprotection.”
Which of the following fetal diagnosis merits preparation for an ex utero intrapartum treatment procedure (EXIT) at delivery?
A. Beckwith-widemann syndrome
B. Anterior encephalocele
C. Pentalogy of cantrell
D. Sacrococcygeal teratoma
E. Tracheal atresia
E.
The ex utero intrapartum treatment (EXIT) procedure is used for selected fetal conditions that severely compromise the fetal airway and therefore the ability of the fetus to transition to neonatal life. The EXIT procedure is an example of open fetal surgery that seeks to establish functional and reliable control of the fetal airway before ligating the umbilical cord. The fetus is delivered partially from a cephalic presentation through the hysterotomy incision, allowing access to the fetal airway while keeping the fetus attached to the uteroplacental circulation, allowing uninterrupted fetal oxygenation and gas exchange. This provides time for laryngoscopy, bronchoscopy, tracheostomy, vascular access, surgical resection, and/or cannulation of extracorporeal membrane circulation (ECMO). The primary indications for EXIT include congenital airway obstruction (eg, laryngeal atresia, tracheal atresia), large head and neck tumors, malformations of the face and jaw, and cases of congenital diaphragmatic hernia after tracheal plugging. Other indications include cases in which neonatal resuscitation may be compromised, such as large congenital cystic adenomatoid malformations (CCAMs) or other thoracic masses, including congenital diaphragmatic hernia (CDH). Due to the complexity of these cases and the need for multidisciplinary expertise, meticulous preparation is necessary with a highly skilled and experienced team of anesthesia, obstetric, and pediatric specialists. Clear assignment of roles and detailed preparation is necessary to ensure optimal communication between the multidisciplinary team as well as with nursing and ancillary staff. The patient is usually placed in Allen stirrups to allow the fetal surgeon to access the surgical field. The EXIT procedure is facilitated by maximum uterine relaxation and maintenance of uterine volume. General anesthesia or combined spinal epidural with uterine relaxants are usually used. The use of uterine muscle relaxants or volatile anesthetics may be associated with maternal hypotension, which can be treated with intravenous fluids and vasopressors (phenylephrine). In all cases, patients are to be placed in a left lateral tilt position to minimize aortocaval compression and maximize uteroplacental blood flow. The primary maternal risk of the procedure is uterine hemorrhage, which should be anticipated and patients are treated with uterotonics immediately after delivery of the fetus. Of the conditions listed, only tracheal atresia is an indication for the EXIT procedure. The other conditions do not result in significant airway compromise. Although Beckwith-Wiedemann syndrome is characterized by overgrowth and macroglossia is a common characteristic, this is generally not severe enough to significantly compromise resuscitation at birth.
Deprest J, et al. (2009). Invasive Fetal Therapy. In Creasy R, Resnik R, Iams J (eds), Creasy and Resnik’s Maternal-Fetal Medicine: Principles and Practice, 6th ed. Philadelphia: Saunders Elsevier. pp 433-451.
Liechty KW. Ex-utero intrapartum therapy.” Semin Fetal Neonatal Med. 2010;15(1): 34-39.
The MOST common site for fetal blood sample is the ______?
A. Fetal heart
B. Fetal intrahepatic vein
C. Umbilical vein close to the abdominal cord insertion
D. Umbilical vein close to the placental insertion
E. Free loop of the umbilical cord
D.
There are several ways to accomplish ultrasound-guided placement of a needle into the fetal circulation: directly into the umbilical cord (either at the placental cord insertion [PCI] or abdominal cord insertion [ACI] or into a free loop); into the intrahepatic portion of the umbilical vein (also called the intrahepatic vein [IHV]); or into the fetal heart (cardiocentesis). Fetal blood sampling (FBS) is most commonly performed via the umbilical vein close to the PCI. It is less commonly performed at the fetal ACI, through penetration of a free loop of cord, or via cannulation of the IHV. Rarely is FBS performed by fetal cardiocentesis (1). The advantages of sampling at the PCI are the relative stability of the cord for easier insertion and shorter procedure time (2). The disadvantage is the possibility contamination by maternal blood, and need to confirm that the sample obtained is indeed of fetal origin. FBS performed from a free loop of cord may result in more bleeding and longer bleeding time due to piercing of the wall of the vessel, although it has the advantage of avoiding placental penetration, and avoiding the need for confirmation of fetal origin. There are currently no published randomized control trials comparing the efficacy and safety of these techniques.
- Society for Maternal-Fetal Medicine (SMFM), Berry SM, Stone J, Norton ME, Johnson D, Berghella V. Fetal blood sampling. Am J Obstet Gynecol. 2013;209:170-180.
- Tangshewinsirikul C, Wanapirak C, Piyamongkol W, Sirichotiyakul S, Tongsong T. Effect of cord puncture site in cordocentesis at mid-pregnancy on pregnancy outcomes. Prenat Diagn. 2011;31:861-864.
- Which of the following is LEAST likely with amniocentesis attempted earlier than 15 weeks
A. Tenting of membranes
B. Limb reduction defects
C. Amniocyte culture failure
D. Rupture of membranes
E. Club foot
B.
In the hands of an experienced provider under continuous ultrasound guidance, the expected rate of pregnancy loss after 2nd trimester amniocentesis is approximately 0.33%. When performed at too early a gestational age, however, additional complications have been reported. The optimal timing for 2nd trimester amniocentesis is at or beyond 15 weeks gestation. Before this, complications that may occur include tenting of the membranes due to incomplete fusion of the chorion and amnion (visible on ultrasound), which occurs in 2–3%. This leads to a failed procedure due to inability to access the amniotic fluid. Fetal talipes equinovarus (club foot), which occurs in 1–2%. This represents a 10-fold increase over the general population. It is hypothesized that the increase in club foot with early amniocentesis is caused by increased leakage of fluid. Fetal loss, which is 1.7% higher than with amniocentesis performed at >15 weeks. Amniocyte culture failure has been reported with early amniocentesis due to a higher ratio of nonviable:viable amniocytes in the fluid. Rupture of membranes occurs more frequently in early amniocentesis. It should be noted that 2–3% of patients experience leakage of fluid after amniocentesis at any gestational age, and unlike previable rupture of membranes these cases often resolve spontaneously after several days. Limb reduction defects are a rare complication of chorionic villus sampling, and have not been reported with amniocentesis at any gestational age.
Creasy & Resnick, 7th edition, Ch 30, pp 450-452.
If fetal endoscopic tracehal occlusion (FETO) for congenital diaphragmatic hernia is considered, which of the following is one possible indication?
A. Liver herniation 10%
B. Lung head ratio (LRH) 0.7
C. Mediastinal shift
D. Observed to expected fetal lung volume 60%
E. Right sided hernia
B.
Congenital diaphragmatic hernia (CDH) occurs in approximately 1 in 3000 to 4000 births with an overall mortality of 50–60%. Associated anomalies occur in 40% of cases and confer a considerably lower survival rate. With isolated CDH, the major cause of mortality is pulmonary hypoplasia and pulmonary hypertension. Given the overall poor prognosis, several prenatal parameters have been studied to assess prediction in cases of CDH. The sonographic lung to head ratio (LHR) calculated as the lung area at the level of the 4 chamber view divided by the head circumference has been studied extensively, with LHR <1.0 associated with poor survival and values <0.8 associated with almost 100% lethality. More recently, magnetic resonance imaging has been used to calculate the observed to expected total fetal lung volume (O/E TFLV). A study of 172 CDH cases by Zamora et al. associated an O/E TFLV <35% with development of chronic lung disease. The same study also associated 20% liver herniation with poor pulmonary outcomes. In general, the side of the lesion is not associated with survival. It is important to note that fetoscopic tracheal occlusion (FETO) is still considered an investigational therapy and has not been established as the standard of care in most parts of the United States. Recently, FETO has been studied for severe cases of CDH. A detachable silicone balloon is placed within the trachea endoscopically using a fetoscope. In a randomized study by Ruano et al. assessing FETO at 22–24 weeks for severe isolated CDH (defined as LHR <1.0, 1/3 liver herniation) survival was seen in 50% (10/20 cases) compared with 4.8% (1/21) controls. A study by the FETO Consortium reported the outcomes of 210 consecutive procedures and found that FETO resulted in a substantial improvement in survival but was associated with high rates of preterm premature rupture of membranes and preterm delivery. Neonatal death has also been reported after difficult balloon removal at time of emergent delivery. A large European study [Tracheal Occlusion to Accelerate Lung Growth (TOTAL) for Severe Pulmonary Hypoplasia] is currently recruiting patients.
Williams Obstetrics 24th edition, Chapter 16, pp 328-329.
Zamora IJ, Olutoye OO, Cass DL, et al. Prenatal MRI fetal lung volumes and percent liver herniation predict pulmonary morbidity in congenital diaphragmatic hernia (CDH). J Pediatr Surg. 2014;49:688-693.
Ruano R, Yoshisaki CT, Da Silva MM, et al. A randomized controlled trial of fetal endoscopic tracheal occlusion versus postnatal management of severe isolated congenital diaphragmatic hernia. Ultrasound Obstet Gynecol. 2012;39:20-27.
Jani JC, Nicolaides KH, Gratacos E, et al. Severe diaphragmatic hernia treated by fetal endoscopic trachael occlusion. Ultrasound Obstet Gynceol 2009;34:304-310.
DePrest J, De Coppi P. Antenatal management of isolated congenital diaphragmatic hernia today and tomorrow: ongoing collaborative research and development. J Pediatr Surg. 2012:47:282.
https://clinicaltrials.gov/ct2… Trachael Occlusion to Accelerate Lung Growth (TOTAL) Trial for Severe Pulmonary Hypoplasia.
Which of the following is the most common indication for fetal intracardiac intervention?
A. Aortic stenosis
B. Hypoplastic left heart with intact septum
C. Pulmonary atresia with evolving hypoplastic right heart
D. Supraventricular tachycardia
E. Ventricular septal defect (VSD)
A.
Severe narrowing of a cardiac outflow tract may result in progressive myocardial damage in utero, but intervention may permit muscle growth and preserve ventricular function. Possible fetal procedures include aortic valvuloplasty for critical aortic stenosis, atrial septostomy for hypoplastic left heart syndrome with intact interatrial septum, and pulmonary valvuloplasty for pulmonary atresia with intact interventricular septum. Of these, fetal aortic valvuloplasty is the most commonly performed. It is offered for selected cases of critical aortic stenosis in which the left ventricle is either normal sized or dilated. The goal is to prevent development of hypoplastic left heart and permit postnatal biventricular repair. It should be noted that evidence for these procedures comes mainly from single institution series. Although these studies have reported favorable outcomes, large prospective studies are lacking and these procedures are still considered investigational. Fetal supraventricular tachycardia, most often atrioventricular reentry or atrial flutter, remains the most common indication for pharmacological fetal intervention but not direct intracardiac intervention.
Williams Obstetrics 24th ed, Chapter 16, p 331.
McElhinney DB, Tworetzky W, Lock JE. Current status of fetal cardiac intervention. Circulation. 2010;121:12256-1263.
Moon-Grady AJ, Morris SA, Belfort M, et al. International Fetal Cardiac Intervention Registry: A worldwide collaborative description and preliminary outcomes. J Am Coll Cardiol. 2015 Jul 28;66(4):388-99.
A primigravida is carrying a fetus with a large congenital pulmonary airway malformation (CPAM). At a 38 week ultrasound there are findings of CVR (CPAM volume ratio) of 1.7, and a mediastinal shift. The best delivery plan is:
A. Ex utero intrapartum treatment (EXIT) procedure to surgical resection
B. Scheduled labor induction and immediate transfer for surgical resection postpartum
C. Scheduled cesarean delivery and immediate transfer for surgical reaction postpartum
D. Spontaneous labor and immediate transfer for surgical resection postpartum
A.
An ex utero intrapartum treatment (EXIT) procedure is designed to allow the fetus to remain perfused by the placental circulation after being partially delivered, so that life-saving treatment can be performed before completing the delivery. Indications for EXIT include tumors involving the neck or airway, EXIT to extracorporeal membrane oxygenation (ECMO) for congenital diaphragmatic hernia, congenital diaphragmatic hernia after fetal tracheal occlusion (FETO), and severe micrognathia. The CPAM volume ratio (CVR) is a calculation performed by taking the length x width x height of the CPAM, multiply that by 0.52, then divide that quantity by the head circumference. A CVR of >1.6 indicates an increased risk of fetal hydrops developing, and merits more intensive monitoring. In a study by Cass et al. assessing the benefit of EXIT to resection for large lung masses (CVR >1.6 and mediastinal shift), 9 babies treated with EXIT-to-resection did well with discharge at a median of 10 days postoperatively. All 7 fetuses treated without an EXIT developed respiratory distress after birth requiring an urgent surgery; 2 died.
Williams Obstetrics 24th ed, Chapter 16, p 331.
Cass DL, Olutoye OO, Cassady I, et al. EXIT-to-resection for fetuses with large lung masses and persistent mediastinal compression near birth. J Pediatr Surg. 2013;48,138-144.
- Which of the following outcomes was shown in randomized controlled trial to be more common after an antepartum open fetal myelomeningocele repair when compared with expectant management and postnatal repair?
A. Increased birth weight
B. Decreased rates of postnatal motor and neurological deficits
C. Increased chorioamnionitis
D. Increased dehiscence at the spina bifida repair site
E. Increased perinatal death
B.
Despite folic acid fortification, the incidence of myelomeningocele is 3.4 per 10,000 live births in the United States. A recent prospective randomized study assigned women to undergo either prenatal surgery before 26 weeks of gestation or standard postnatal repair. One primary outcome was a composite of fetal or neonatal death or the need for placement of a cerebrospinal fluid shunt by the age of 12 months. Another primary outcome at 30 months was a composite of mental development and motor function. The trial was stopped early for efficacy of prenatal surgery after the recruitment of 183 of a planned 200 patients. The first primary outcome occurred in 68% of the infants in the prenatal surgery group and in 98% of those in the postnatal surgery group (relative risk [RR] 0.70; 97.7% confidence interval [CI] 0.58 to 0.84). Actual rates of shunt placement were 40% in the prenatal surgery group and 82% in the postnatal surgery group (RR 0.48; 97.7% CI 0.36 to 0.64). Prenatal surgery also resulted in improvement in the composite score for mental development and motor function at 30 months (P=0.007) and in improvement in several secondary outcomes, including hindbrain herniation by 12 months and ambulation by 30 months. However, prenatal surgery was associated with an increased risk of preterm delivery, decreased birth weight, and uterine dehiscence at delivery. There were no differences in chorioamnionitis rates, dehiscence at the primary repair site, or perinatal death. Extensive patient counseling about the pros and cons of in-utero surgery is appropriate for each case.
Adzick NS, et al. A randomized trial of prenatal versus postnatal repair of myelomeningocele. N Engl J Med. 2011;17;364(11):993-1004.
A 24 year old G2P1 is receiving intravenous immunoglobulin (IVIG) and prednisone therapy because her prior child was diagnosed with intracranial hemorrhage at birth. Subsequent neonatal evaluation revealed severe thrombocytopenia and partner testing revealed homozygous human platelet antigen (HPA) status. The benefit of percutaneous umbilical blood sampling (PUBS) at 32 weeks in the current pregnancy would be:
A. Increased IVIG dose if the platelets are low
B. Increased prednisone dose if the platelets are low
C. Delivery mode planning
D. There is no benefit to PUBS in this case
C.
Fetal and neonatal alloimmune thrombocytopenia (NAIT) is the most common etiology of severe thrombocytopenia in fetuses and neonates, and of intracranial hemorrhage in term newborns. Unlike Rh isoimmunization, which increases in severity in subsequent pregnancies, NAIT can result in a severe neonatal outcome even in the first pregnancy. Management in subsequent pregnancies depends on paternal HPA antigen testing, the presence or absence of intracranial hemorrhage in the prior pregnancy, and the timing of the diagnosis of hemorrhage. In women with a hemorrhage diagnosed after 28 weeks gestation (including after delivery), the typical therapy in a subsequent pregnancy includes IVIG therapy starting at 12 weeks gestation, with either an increase in IVIG dose or additional prednisone from 20–28 weeks gestation, and finally high dose IVIG (2 g/kg/week) and prednisone (0.5 mg/kg/day) after 28 weeks.The benefit of PUBS at 32 weeks gestation is the opportunity for a vaginal trial of labor if the platelets are greater than 100,000 mm3. It is also appropriate to plan for cesarean delivery without cordocentesis.
Pacheco LD, et al. Fetal and neonatal alloimmune thrombocytopenia – A management algorithm based on risk stratification. Obstet Gynecol. 2011;118(5):1157-1163
- For which of these patients is the evidence supporting cerclage placement the strongest?
A. Singleton gestation, no history of preterm birth, cervical length 25 mm
B. Singleton gestation, no history of preterm birth, IVF pregnancy, nervous about an early delivery
C. Twin pregnancy, history of preterm birth, cervical length 24 mm
D. Singleton gestation, history of preterm birth, cervical length 30 mm
E. Singleton gestation, history of preterm birth, cervical length 20 mm
E.
A multicenter, randomized controlled trial examined the role of serial transvaginal cervical length screening, with cerclage placement for cervical length <25 mm, among women with singleton gestations and prior spontaneous preterm births at less than 34 weeks of gestation, including some women who received 17a-hydroxyprogesterone caproate. This study showed a decrease in preterm birth <24 weeks and 37 weeks with cerclage placement for those with cervical length <25 mm. Those without a history of preterm birth should be offered vaginal progesterone, which has been noted to decrease the risk of preterm birth, and not cerclage placement. Berghella et al. performed a meta-analysis of ultrasound-indicated cerclage and reported that when cervical length was less than 2.5 cm between 14–23 6/7 weeks gestational age, a 40% reduction in preterm birth was observed in singletons receiving a cerclage. They found an increase in preterm birth when the indication for cerclage placement was multiple gestations.
Prediction and prevention of preterm birth. Practice Bulletin No. 130. American College of Obstetricians and Gynecologists. Obstet Gynecol. 2012;120:964–73.
Iams JD, Romero R, Creasy RK. Preterm labor and birth. In: Creasy RK, Resnik R, Iams JD, eds. Creasy and Resnik’s Maternal-Fetal Medicine: Principles and Practice. 6th ed. Philadelphia, PA: Saunders/Elsevier; 2009, pp 550-560.
Owen J, Hankins G, Iams JD, et al. Multicenter randomized trial of cerclage for preterm birth prevention in high-risk women with shortened midtrimester cervical length. Am J Obstet Gynecol. 2009;201:375.e1-8.
Berghella V, Odibo AO, To MS, et al. Cerclage for short cervix on ultrasonography: meta-analysis of trials using individual patient-level data. Obstet Gynecol. 2005;106:181-189. Berghella V, Rafael TJ, Szychowski JM, et al. Cerclage for short cervix on ultrasonography in women with singleton gestations and previous preterm birth: a meta-analysis. Obstet Gynecol. 2011;117:663 –671.
