Impacted Fetal Head

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Reading: From SASCOG’s Pearls of Exxcellence - Cesarean Delivery with Deeply Impacted Fetal Head 

Imagine the scenario: 

You are called to do an urgent C-section as an intern for a patient with arrest of second stage of labor. Per sign out, the patient has been pushing for almost three hours and the fetal station has never made it below +1. There is significant caput. What are some of the things you should be thinking about to hopefully make this C-section easier? 

How do I identify an impacted fetal head? 

  • What it is: 

    • There have been various definitions proposed - basically, most of the definitions center on having a fetal head becoming deeply engaged within the maternal pelvis resulting in difficult extraction 

    • Complicates 1.5% of cesarean births and up to 25% of emergent cesarean births 

  • Risk factors 

    • Fetal malposition - ie. occiput posterior and occiput transverse positions

      • OP positioning leads to a larger occipitofrontal diameter (11.5cm) passing through the pelvic outlet compared to OA (9.5 cm) 

      • See more on this in our malposition and malpresentation episode!

    • Prolonged second stage 

    • Failed operative vaginal delivery 

    • Basically, anything that can wedge the head into the pelvis 

  • Identifying an impacted fetal head 

    • There is not a 100% way of identifying that a fetal head will be impacted before you actually do the C-section and you reach down into the pelvis 

    • However, you should suspect it if there are any of the above risk factors 

    • Regarding fetal position: 

      • Can be known by palpating the sutures

      • In babies that are OP, the posterior fontanelle will be felt

        • This feels triangular, as it is formed by the junction of the sagittal and lamboidal sutures 

      • This is in contrast to babies that are OA, where the anterior fontanelle can be felt (shaped like a diamond) 

      • Other methods = using transabdominal ultrasonography to figure out position, as rate of error for digital vaginal exam can range from 30-65% depending on the study 

    • An impacted fetal head is usually identified during the cesarean delivery: when you place a hand beneath the pubic bone to lift the fetal head, it is often difficult due to how low the head is.

      • Possibly cannot get hand around the fetal head to elevate 

      • Or it is difficult to elevate and flex the head due to position or how low the head is 

Why do we care about IFH? 

  • What are risks to mom? 

    • Other than it being really hard to elevate the head and delivering the baby, there are multiple risks to both mother and infant at this stage 

    • Increased risk of: 

      • Maternal hemorrhage 

      • Hysterotomy extensions 

      • Bladder injury 

  • What are risks to baby? 

    • Neonatal hypoxia 

    • Traumatic injuries 

  • Therefore, important to identify this and anticipate how to resolve IFH 

What should you do if there is a suspected impacted fetal head? 

  • Let others know what you are thinking 

    • Tell nursing staff, anesthesia, and neonatology 

      • This way, everyone is prepared 

    • Call for help if needed - if you need another team member to come in for assistance, it’s better to have them and not need them than if no one is there 

  • Position the patient accordingly 

    • We tend to favor positioning patient in a modified lithotomy position 

      • Can either frog-leg 

      • Or place in lithotomy, but bend legs down so that the hip joint is not flexed during the initial part of the case

        • Can use yellow fin stirrups 

        • Easy to then flex at the hip joint into dorsal lithotomy if needed  

  • Place your hysterotomy accordingly 

    • Especially if the patient has entered second stage, the lower uterine segment will be distended 

    • Hysterotomy should be placed relatively high to avoid inadvertent entry through the cervix or vagina 

  • Maneuvers to resolve IFH 

    • Now that you have encountered an impacted fetal head and done all the right things up until now. How do you get the baby out? 

    • Vaginal hand or “push” technique 

      • Someone wears sterile gloves and inserts hand into vagina to elevate the fetal head 

      • They do not remove the hand until the head has been disimpacted by the surgeon from above or if this method has failed 

    • Breech delivery or “pull” technique 

      • Another technique is to deliver breech

      • Surgeon will extract feet from hysterotomy and proceeds to deliver the rest of the fetus 

        • Studies in low-resource settings show that this technique resulted in decreased maternal hemorrhage, hysterotomy extensions, and infection when compared to the “push” technique  — comparison of different methods via systematic review and meta-analysis

    • Extending your hysterotomy

      • If extraction is still difficult, can proceed with extension of the hysterotomy either via a J or a T extension 

      • These are done usually with two fingers beneath the area that you wish to extend to protect the baby, then cut the uterus with bandage scissors 

      • Can lead to more bleeding and will result in longer repair, but may lead to increased 

    • Devices 

      • Fetal Disimpacting System or cephalic elevation device; Fetal Pillow

      • Basically an inflatable device that is placed into the vagina that elevates the fetal head!

  • One randomized controlled trial at BWH in Boston that showed that this device led to 23-second reduction from hysterotomy to delivery compared with other methods 

    • Patients all received the device in the vagina, but were randomized to whether or not the device was inflated or not.

  • Other techniques 

    • Other techniques have been described, but not as well studied as the push or pull technique 

    • One = shoulder-first method, where the shoulders are initially delivered through the hysterotomy, followed by traction placed on axilla to facilitate delivery of the body and subsequently the head (Patwardhan maneuver)

  • Last thoughts 

    • If an IFH occurs, and it is particularly difficult, especially if it leads to need for multiple maneuvers, remember to debrief! 

    • Both with the team - what happened, what went well, what could have been improved, and take home points 

    • Talk to the patient 

      • Often, this can be traumatic for both the provider and the patient 

      • The baby may need to go the NICU, there may need to be a hysterotomy extension 

      • Discuss what occurred with the patient and if maneuvers resulted in certain complications 

        • Discuss extensions, baby going to NICU

        • Discuss if need for future C-section if T incision has occurred 

Espresso: Zuranolone for Postpartum Depression

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We’re back! While we’ll operate for a bit on a reduced schedule (new episodes every-other-week), we are so excited to get back to podcasting and covering the need-to-know in OB/GYN. Thanks for all the love and support over the last few months! <3 Nick & Fei

Reading: Zuranolone for the Treatment of Postpartum Depression (ACOG Practice Advisory)

What is zuranolone and why is it important? 

    • We know that postpartum/perinatal mental health conditions and some of the leading causes of preventable maternal mortality 

      • PPD affects approximately 14% of women 

      • Understanding/discussing/recommending medication and treatment can potentially decrease maternal morbidity and mortality 

  • Medication type

    • Neuroactive steroid gamma-aminobutyric acid (GABA) A receptor positive modulator 

    • Oral medication  

    • Recent FDA approval for use in PPD 

Why is zuranolone recommended, and what else is out there? 

  • Why is it recommended? 

    • Two phase 3 randomized double-blind, placebo-controlled multicenter studies 

    • Primary endpoint in both: change in depressive symptoms in the Hamilton depression rating scale (HAMD-17) 

      • 17 point scale 

      • Assesses somatic (physical ie. loss of appetite), affective (mood ie. sadness), cognitive (thinking, ie. difficulty concentrating), and behavioral (ie. social withdrawal) symptoms of depression 

      • Reliable and valid method of assessing and measuring depression 

    • In both studies, those on Zuranolone showed significantly more improvement in their symptoms compared those in placebo 

      • Treatment effect maintained at day 42 (4 weeks after last dose of zuranolone) 

  • Why the HAMD-17? 

    • More used in research settings, but anticipated that other validated tools (like EPDS or PHQ9) will be used in clinical settings 

  • What else is out there? 

    • Brexanolone - first FDA approved medication specifically for postpartum depression

      • However, unlike zuranolone which is oral, brexanolone consists of a 60 hour in-hospital IV infusion, which may not be readily accessible 

        • May be difficult to arrange inpatient admission 

        • May also be difficult for patients to leave their newborns for 60 hours to get infusion 

    • SSRIs 

      • Not specific for postpartum/perinatal depression 

      • Can be effective, but also may be difficult to find the correct SSRI

      • Many SSRIs also require uptitration of dosage 

  • What to consider when prescribing zuranolone 

    • Consideration of zuranolone in the postpartum period (within 12 months postpartum) for depression that has onset in the third trimester or within 4 weeks postpartum

    • Benefits: 

      • Significantly improved and rapid resolution of symptoms 

    • Risks: 

      • Potential suicidal thoughts or behavior 

      • Sedation - can make it so you can’t drive 

      • Lack of efficacy data beyond 42 days 

  • How to prescribe and take zuranolone 

    • Daily recommended dose is 50 mg 

      • Take in evening with fatty meal (400-1000 calories, 25-50% fat) for 14 days 

      • Can reduce dose to 40 mg if CNS depression effects occur 

      • If hepatic or renal impairment, start dose at 30 mg 

    • Can be used alone or as an adjunct to other oral antidepressant therapy like SSRIs 

    • Recommendation is to have effective contraception during treatment and for 1 week after final dose. There is a registry if pregnancy occurs 

    • Warn patients about adverse reactions 

      • Impaired ability to drive 

      • CNS depressant effects 

      • Increased suicidal thoughts and behaviors 

    • Zuranolone does pass into breastmilk, but relative infant dose is smaller than that of SSRIs 

Physiologic Changes of Pregnancy: Part 2

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10/08/2023
As part of our brief break for parental leave, we’re revisiting some of our most popular episodes! Today we’re revisiting Physiologic Changes of Pregnancy, part II.

We’re continuing “Fei and Nick’s Fabulous Adventure Through Pregnancy” today!

Need a refresher on all those lung volumes? So did we. There are a number of resources online to review them, however a nice quick video review can be found here.

These two episodes have covered a lot of ground on a lot of systems. We tried to come up with a quick-view table encompassing all of these changes. Let us know what you think!

Physiologic Changes of Pregnancy: Part 1

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10/01/2023
As part of our brief break for parental leave, we’re revisiting some of our most popular episodes! Today we’re revisiting Physiologic Changes of Pregnancy - almost five years to the day since we released it! Check out our reprisal of part II next week with the all-encompassing table of changes.

As promised, our first episode on pregnancy! Join us on “Fei and Nick’s Fabulous Adventure Through Pregnancy!”

Today we tackled the changes of the immunologic and hematologic systems seen in pregnancy. There’s quite a bit of information there! If you feel like we’ve missed anything, feel free to reach out via email or social media.

Next week, we’ll release Part 2 and have some more resources ready for your studying!

Updates with Respiratory Syncytial Virus (RSV)

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Since the recording of this episode, the RSV vaccine has officially been approved by the CDC and should be available starting this month!

What is RSV? 

  • RSV = respiratory syncytial virus 

    • Negative sense, single-stranded RNA virus 

    • Name is derived from the large cells known as syncytia that form when infected cells fuse 

  • Why do we care? 

    • Usually causes mild, cold-like symptoms in healthy individuals, and most people will recover in 1-2 weeks 

    • Most of the time, symptoms are localized to upper respiratory tract, but can also cause lower respiratory tract infections 

    • However, infants and older adults are more likely to develop severe disease that require hospitalization 

    • Most children under the age of 2 will contract RSV due to contact with others 

      • Most common cause of bronchiolitis and pneumonia in children <1 year 

      • Leads to 2.1 million outpatient visits as well as 58,000 - 80,000 hospitalizations per year 

      • Also leads to 100-300 deaths among children <5 annually 

    • Those at risk for severe disease 

      • Premature infants and infants <6 months 

      • Individuals with chronic heart or lung disease 

      • Those with immunocompromise 

      • Older adults (65+) 

Why are we discussing RSV now? 

  • Because patients are going to start asking you about it due to two recent developments! 

  • RSV Vaccine 

    • Recently, FDA approved the Abrysvo vaccine for RSV use in infants up to 6 months of age and older adults (July 2023) 

    • Even more recently (8/21/2023), the FDA approved the RSV vaccine for pregnant individuals to prevent RSV in infants 

      • Approved for use between 32-36 weeks gestation 

      • Antibodies can cross the placenta and protect the infant for up to 6 months of age 

      • However, the CDC has not yet set recommendations about Abrysvo, and will not do so until October 2023 

    • This is a bivalent vaccine composed of two recombinant RSV fusion surface glycoproteins to protect against RSV A and B strains 

    • The Data - two randomized controlled trials  

      • Pregnant patients - 3682 patients weeks 24-36 weeks were given the vaccine and 3697 received placebo 

        • There were significantly fewer medically attended severe lower respiratory tract illnesses in infants within 90 days after birth in those that received the vaccine (efficacy 81.8%, 99.5% CI 40.6- 96.3) 

        • There were also fewer medically attended severe lower respiratory tract illnesses within 180 days after birth (efficacy 69.4%, 97.58% CI 44.3-84.1%) 

        • Similar adverse events in both groups 

          • However, in safety studies, low birth weight and jaundice in infants occurred in higher rate in the vaccine group 

          • There is also an imbalance of preterm births in abrysvo recipients (5.7%) vs. placebo (4.7%), but data is currently insufficient to establish a causal relationship with the vaccine 

          • This is why current recommendation is to give after 32 weeks of gestation 

      • Older adults - >18,000 adults 60 years or older were given vaccine, and another >18,000 similar cohort were given placebo 

        • Significantly fewer RSV-associated lower respiratory tract illnesses with two signs or symptoms in the vaccine group compared to placebo group (efficacy 66.7%, 96.7% CI 28-85.8)

        • Significantly fewer RSV-associated lower respiratory tract illness with 3 signs or symptoms in vaccine group (efficacy 85.7%, 96.7% CI 32-98.7) 

        • Higher rates of local reaction with vaccine (12% vs. 7%), and similar rates of adverse events through 1 month after injection 

      • Currently, FDA is requiring the company to conduct postmarketing studies to assess risk of preterm birth and pre-eclampsia 

  • RSV Monoclonal Antibody 

    • FDA has approved the use of nirsevimab (trade name Beyfortus, a long-acting monoclonal antibody) for use to prevent lower respiratory tract disease due to RSV in infants and young children on 7/17/2023 

    • Recommendation 

      • All neonates and infants born during or entering their first RSV season at <8 months of age may receive this antibody for prevention 

      • Also children up to 24 months of age who remain vulnerable to severe RSV disease through their second RSV season 

        • Includes children who are at immunocompromised 

    • Administered as single IM injection 

    • The Data - 3 clinical trials 

      • In one trial of preterm infants born at 29-35 weeks gestation, 969 received single dose of nirsevimab, and 484 received placebo 

        • Those who received nirsevimab, 2.6% experienced medically attended RSV LRTI, compared to 9.5% of infants who received placebo (reduces risk by 70%) 

      • Another trial of infants born at >35 weeks gestation, 994 received nirsevimab, and 496 received placebo 

        • Antibody group had 1.2% MA RSV LRTI compared to 5.0% of infants who received placebo (reduces risk by 75%) 

      • Final trial was a randomized, double-blind, active-controlled multicenter trial to prove safety 

        • Beyfortus vs. palivizumab (monoclonal antibody used previously to decrease severe disease caused by RSV; only used in those children at high risk for RSV, including premature infants <35 weeks gestation who are also <6 months of age, children <2 who require treatment for bronchopulmonary dysplasia, and children <2 who have hemodynamically significant congenital heart disease) 

        • 925 preterm infants and infants with chronic lung disease of prematurity or congenital heart disease → Beyfortus was non-inferior in terms of safety 


Some lingering questions 

  • When will the vaccine and monoclonal antibody be available? 

    • The monoclonal antibody should be available this fall, per FDA 

    • Vaccines should be available at doctor’s offices and at pharmacies if CDC approves in October 

    • Monoclonal antibody should be available at pediatrician’s offices and in hospitals after delivery 

  • What is the cost? 

    • Per the American Academy of Pediatrics, one dose of Beyfortus is $495 for both the 50 mg and 100 mg doses 

    • Per Pfizer, the RSV vaccine Abrysvo will cost somewhere between $180-$270 

    • For reference, the pediatric influenza vaccines cost somewhere between $14 - $30