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!

Breastfeeding Part II: Facts and Myth-busting

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Today we (finally!) sit down with Part II of our breastfeeding special with Dr. Erin Cleary to cover myths, facts, and advantages of breastfeeding.

There are only three main contraindications to breastfeeding:
1. In infants with galactosemia.
2. In mothers who are HIV+ in high-resource settings.
3. In mothers with human T-cell lymphoma virus.

There are a number of relative contraindications to breastfeeding:

  • In a mother with Hepatitis A until she receives gamma globulin.

  • In a mother with Hepatitis B until the infant receives HBIG and HepB vaccine.

  • In a mother with Hepatitis C if coinfections present, such as HIV.

  • In a mother with Varicella zoster (Chicken pox) while mother is infectious.

  • In a mother with Active TB until mother has received 2+ weeks treatment

  • In a mother with influenza

    • if the mother has been afebrile without antipyretics for >24 hours, and the mother is able to control her cough and respiratory secretions.

    • Oseltamivir or Tamiflu is poorly excreted in breastmilk

  • In patients abusing IV drugs.

  • In patients using marijuana:

    • (THC), the main compound in marijuana, is present in human milk up to eight times that of maternal plasma levels, and metabolites are found in infant feces, indicating that THC is absorbed and metabolized by the infant

    • Several preclinical studies highlight how even low to moderate doses during particular periods of brain development can have profound consequences for brain maturation, potentially leading to long-lasting alterations in cognitive functions and emotional behaviors

    • Breastfeeding mothers should be counseled to reduce or eliminate their use of marijuana to avoid exposing their infants to this substance and advised of the possible long-term neurobehavioral effects from continued use

Common Breastfeeding Myths/Misconceptions:

Infectious:

  • You should breastfeed if you have mastitis, emptying the breast prevents stasis of milk

You can breastfeed in setting of acute respiratory, urinary, GU infections, continuation of BF acceptable

Imaging Sudies

  • You can breastfeed if… You need medical imaging.

    • XRays do not affect milk

    • Mammograms may be harder to interpret when a patient is lactating, but this should not be a reason to defer recommended diagnostic imaging

    • CT/MRI with or without contrast do not impact breastmilk

    • XRays with contrast dye or imaging with radioactive material are also OK

    • Exception: thyroid scan using I-131

      • I-131 concentrates in breastmilk and at high levels can suppress baby’s thyroid function (or even destroy the thyroid) and increase risk of thyroid cancer.

      • Therefore it is important that breastfeeding be discontinued until breastmilk levels are safe (this depends upon the dose and ranges from 8 days to 106+ days). The half-life for I-131 is 8.1 days.

      • Hale recommends that when I-131 is used, breastmilk samples should be tested with a gamma (radiation) counter before breastfeeding is resumed to ensure that radiation in the milk has returned to safe levels.

  • You can breastfeed if… You are pregnant!  

    • Increasing progesterone will decrease supply and cause breast/nipple sensitivity.  

    • Mature milk will be replaced by colostrum in the 2nd trimester.

    • Tandem feeding includes breastfeeding a newborn and toddler

  • You can breastfeed if… You’ve had general anesthesia.  As soon as you are awake enough to hold the baby, the medication has metabolized and breastfeeding is safe.

  • You can breastfeed if… You are on maintenance medications such as methadone and buprenorphine

    • There is a reduction in severity and duration of treatment of NAS when mothers on these medications breastfeed

  • You can breastfeed if… You have an occasional alcoholic beverage

    • Alcohol concentration in the blood is in steady state with the milk, so delaying nursing or pumping until more alcohol is metabolized can limit exposure

  • If direct breastfeeding is interrupted due to temporary separation of mother and child for any reason, the breastfeeding mother should be encouraged and supported to regularly express her milk.

    • Expression and storage of milk allows the infant to continue to receive milk if appropriate, and prevents stasis of milk and mastitis

In the setting of infection, prior to expressing breast milk, mothers should wash their hands well with soap and water and, if using a pump, follow recommendations for proper cleaning.

HIV in the Pregnant Patient

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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

Hypertension and Pregnancy Trio

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We’ve had an overwhelming response to our Espresso episode on acute treatment of severe hypertension in pregnancy, so today we have a special triple episode release on pregnancy and hypertension! We dive into ACOG PB 202 on Preeclampsia and Gestational Hypertension, and ACOG PB 203 on Chronic Hypertension in Pregnancy (membership required for both).

In our first episode, we dive into risk factors and definitions to set the stage. Recall several risk factors that may raise your suspicion for these disorders:
- Nulliparity
- Multiple gestation
- Chronic hypertension
- History of hypertensive disorder of pregnancy in previous pregnancy
- Pregestational or gestational diabetes mellitus
- Thrombophilia, Anti-phospholipid syndrome, or SLE
- Chronic kidney disease
- Advanced maternal age > 35 years
- Obesity (BMI > 30) or obstructive sleep apnea
- Conception via assisted reproductive technology

In episodes 2 and 3, we dive into the specific definitions and management for each hypertensive disorder. Here are our show notes in table format; we hope that this helps you with your own review!

And in closing, a few postpartum/future health pearls to consider:
- With a history of any of these hypertensive disorders, baby aspirin is indicated in future pregnancies beginning at 12 weeks gestation to reduce risk or delay onset of preeclampsia.
- Women with a history of preeclampsia have 3-4x higher lifetime risk of hypertension, and 2x lifetime risk of heart disease and stroke, thus its important to ask about these even with just the annual physical.
- Best available evidence suggest NSAIDs are OK to use postpartum for patients with hypertensive disorders of pregnancy.
- Best available evidence also supports use of parenteral magnesium for seizure prophylaxis in patients who develop any of these disorders during the postpartum period (generally onsets within first week, but has been reported up to 8 weeks after delivery!).

Further reading from the OBG Project:
And get updates on this and more content, as well as other awesome features for FREE if you’re a PGY-4 — sign up for OBG First!
Diagnosing Preeclampsia: Key Definitions and ACOG Guidelines
ACOG Preeclampsia Guidelines: Antenatal Management and Timing of Delivery
Aspirin Treatment for Women at Risk for Preeclampsia: ACOG and USPSTF Guidelines
Chronic Hypertension in Pregnancy: Diagnosis and BP Measurement
Chronic Hypertension in Pregnancy: Evaluation and Management
The 2017 AHA/ACC Blood Pressure Guidelines
#GrandRounds: Does Hypertension in Pregnancy Predict Hypertension in Later Life?