The Evidence-Based Cesarean Section

Today we go through the steps of cesarean delivery from an evidence basis. We hope this helps everyone from the new interns starting up in just a few weeks to senior residents thinking more about their technique and teaching. The essential article on this from AJOG in 2013 can be found here. However, there have been a number of other articles and talks since, including one regularly given at the ACOG Annual Meeting (check out the 2017 edition by Dr. Strand here), that you all may be aware of and that we encourage you to check out.

One of the more challenging things to relay in the podcast is incisional technique, particularly comparing the traditional Pfannenstiel technique to newer techniques such as Joel-Cohen or Misgav-Ladach. We summarize the differences in those techniques here:

(C) CREOGs Over Coffee (2019)

What’s the difference in these skin incisions?

  • Pfannenstiel: traditionally taught as a curved incision made two finger breadths above the symphysis pubis, with the mid portion of the incision generally within the superior-most aspect of the pubic hair.

  • Joel-Cohen: a straight incision made 3cm below the imaginary line that connects the ASIS on either side. Ultimately this is slightly higher than the Pfannenstiel.

  • Maylard: curved incision made 5-8 cm obove the pubic symphysis. The rectus fascia and muscle are cut transversely, and the inferior epigastric arteries must be ligated.

  • Cherney: using the same skin incision as a Pfannenstiel, but then blunt dissection is used to identify the rectus muscle tendons at their insertion to the public symphysis. They are cut 1-2 cm above their insertion point. On closure, the muscles should be reattached to the anterior rectus sheath, as reattaching to the pubic symphysis may serve as a nidus for osteomyelitis.

Vaccines II: MMR, Varicella, and HPV

Let’s tackle the second part of our vaccinations series with some of the more common live-virus vaccines: MMR, Varicella, and HPV. Check out the CDC vaccine guides linked here.

MMR

  • Measles, mumps, and rubella - all are live attenuated strains of the virus

  • Should NOT be given during pregnancy

  • Immunity is about 97% against measles and rubella after 2 doses, and 88% against mumps after 2 dose

  • Given ideally before pregnancy to protect against congenital rubella

    • Otherwise, after pregnancy and not during

    • This is because during pregnancy, the adaptive immune system is not as robust as when one is not pregnant and higher risk of the live attenuated virus actually causing disease.

      • If an adult is not immune to MMR (and we screen for rubella during pregnancy), at least one dose should be given postpartum.

  • Ingredients

    • Chicken embryo cell culture - medium

    • Human diploid lung fibroblasts - medium

    • Vitamins, amino acids, sucrose, glutamate, human albumin, sorbitol, gelatin, sodium phosphate, sodium chloride

    • Fetal bovine serum - medium

    • Neomycin - antibiotic

  • Side effects

    • Can get rash, temperature, loss of appetite 2-3 days

    • Can get a VERY mild form of measles or mumps

    • Extremely rare: severe allergic reaction

Varicella

  • Protects against chickenpox and shingles

    • 88-98% effective at preventing varicella after two doses, and 85% effective after 1 dose.

    • Ideally given before pregnancy to protect against chickenpox complications during pregnancy (ie. pneumonia) and congenital varicella syndrome or neonatal varicella.

    • Don’t give it during pregnancy.

  • Ingredients

    • Human diploid cells with DNA and protein

    • Sucrose, gelatin

    • Sodium chloride, monosodium-glutamate, sodium phosphate, potassium phosphate, potassium chloride, EDTA

    • Neoomycin

    • Fetal bovine serum

  • Side effects

    • Common: sore arm, fever, mild rash, temporary pain and stiffness

    • Severe: (very uncommon) - severe infection, pneumonia

HPV

  • Gardasil 9 protects against human papilloma virus 16, 18 (causes 80% of cervical cancer cases), 6, 11 (90% of genital wart cases), and another 5 types (31,33,45, 52, 58) that can lead to cervical cancer.

    • 3 separate shots for people aged 15-45 - high efficacy, with close to 100% prevention of HPV virus

    • If 9-14, 2 shots are sufficient

    • Not currently recommended during pregnancy

      • Good time to give it: immediately pp in hospital (dose 1), then 6 weeks pp  

  • Ingredients

    • Vitamins, amino acids, mineral salts, carbohydrates

    • Amorphous aluminum hydroxyphosphate sulfate

    • Sodium chloride

    • Polysorbate 20

    • Neomycin, yeast protein

  • Side effects

    • Common: pain, redness, swelling of arm where shot was given

    • Less likely: fever, headache, feeling tired, nausea, muscle or joint pain.

Vaccines I: Tdap and Influenza

Today we get a little political to arm you with the most up-to-date information on vaccines. We’ll start with the two vaccines recommended in pregnancy: Tdap and Flu. We summarize some of the salient details below:

(C) CREOGs Over Coffee


Now onto some of these controversial ingredients:

  • Formaldehyde - this is used to inactivate viruses and detoxify bacterial toxins

    • Why are people concerned? Because they hear that formaldehyde is used in glues and adhesives, used in preserving dead bodies,  used in insulation materials. In high levels and long-term exposure, formaldehyde IS linked to cancer development.

    • But it is safe! There is always a small amount  of formaldehyde in humans at all times as a normal part of our metabolism (it’s in the air and all around us). In a normal two-month old, there is around 1.1mg of formaldehyde circulating in the body, which is 50-70x more formaldehyde than is present in one dose of vaccine.

  • Octylphenol ethoxylate (Triton X-100) - basically a detergent. Present in trace amounts

  • Sodium phosphate-buffered isotonic sodium chloride solution - this is salt water, it’s used as a buffer

  • Thimerosol - mercury containing ingredient that acts as a preservative.

    • Why are people concerned? The word mercury. Large amounts can be harmful

    • In vaccines this is ethylmercury, which is different from methylmercury, which is the mercury compound that is harmful. Ethylmercury is much more quickly metabolized and removed from your body.

      1. It’s like being afraid of sodium.  Sodium on it’s own will explode if you put it on water. Sodium chloride is salt that you eat.

      2. Even now… only multi-dose flu vaccines have thimerosol, and thimerosal-free vaccines are widely available.

  • 1,2-phenoxyethanol - preservative; it is metabolized and excreted.

  • Aluminium phosphate - used as an adjuvant in vaccines. Makes it more effective by strengthening immune system response, so people need fewer doses of the vaccine to build immunity.

    • Why are people concerned? There has been concern that long-term exposure to high amounts of aluminum can contribute to brain and bone disease

    • Why are we not concerned? There are trace amounts of aluminum in water, food, breast milk

      • A breast-fed patient will ingest about 7 mg of aluminum in 6 months of life . The standard vaccine administered over the first six months of life averages to just 4.4 mg. The amount in a single vaccine is so small that there is no noticeable raise in the base amount found in the blood even immediately after injection.

HIV in the Pregnant Patient

Today we go into part 2 of our HIV series, this time focusing on pregnancy and HIV. Check out ACOG CO 752 (Prenatal and Perinatal HIV Screening) and CO 751 (Labor and Delivery Management of Women with HIV).

However, we have to give a major shout out to the OBG Project — their editors have put out an awesome summary of HIV in pregnancy and preventing vertical transmission: Check it out here.

(c) OBG Project

One of the important CREOG points on HIV in pregnancy includes drug interactions. Methergine is metabolized by CYP3A4 enzymes, which may be inhibited by certain antiretrovirals. Thus, methergine should be avoided if possible if encountering postpartum hemorrhage.

Lastly, we wanted to drive home the point again about patient autonomy, especially regarding risk of cesarean delivery. We put the ACOG CO text below for you to chew on!

ACOG CO 751