Chapter 10 ties together several earlier chapters. It explains how the mother’s immune system tolerates the fetus, how the placenta participates in immune protection, why Rh disease occurs, how newborns receive passive immunity, and why infection prevention is so important during pregnancy. For a midwife, this chapter is highly practical because it affects prenatal care, newborn care, breastfeeding, and infectious disease counseling.

Chapter 10 – Overview of Immunology

1. Read Coad, Anatomy & Physiology for Midwives, 4th edition, chapter 10.
2. Write out your answers to Coad, Chapter Case Study, page 265.
3. Create a Coad “Chapter 10 Study Sheet.” Include the following:

Learning Goals

□ Describe the innate and adaptive immune systems.

□ Explain how pregnancy alters maternal immunity.

□ Explain why the maternal immune system normally does not reject the fetus.

□ Describe passive immunity transferred through the placenta and breast milk.

□ Explain Rh incompatibility and its prevention.

□ Describe the newborn’s immature immune system.

□ Explain basic principles of immunization during pregnancy and infancy.

□ Describe the effects of HIV and other significant infections on pregnancy.

Essential Vocabulary

General Immunology

• Immune system
• Innate immunity
• Adaptive (acquired) immunity
• Antigen
• Antibody
• Immunoglobulin
• Cytokine
• Inflammation
• Immune tolerance

Cells

• B lymphocyte
• T lymphocyte
• Helper T cell
• Cytotoxic T cell
• Natural killer (NK) cell
• Macrophage
• Neutrophil

Antibodies

• IgG
• IgA
• IgM
• IgE
• IgD

Pregnancy

• Passive immunity
• Maternal-fetal tolerance
• Rh factor
• Rh sensitization
• Hemolytic disease of the fetus and newborn (HDFN)
• Rho(D) immune globulin (Rhogam)

Newborn

• Colostrum
• Breast milk antibodies
• Neonatal immunity

Draw

1. Immune System Overview

Immune System

↓

Innate
• Immediate
• Nonspecific

↓

Adaptive
• Specific
• Memory

2. Passive Immunity

Mother

↓

Placenta

↓

IgG

↓

Baby

Then add:

Mother

↓

Colostrum

↓

IgA

↓

Baby

This is probably the most useful diagram in the chapter.

3. Rh Sensitization

Draw:

Rh-negative mother

↓

Rh-positive baby

↓

Fetal blood enters maternal circulation

↓

Mother develops antibodies

↓

Future Rh-positive pregnancy at risk

Concepts I Must Know

Processes I Must Understand

• Immune response
• Antibody production
• Placental transfer of IgG
• Breast milk transfer of IgA
• Maternal immune adaptation
• Rh sensitization
• Prevention of Rh disease
• Neonatal immune development

Midwifery Connections

Clinical Connections

Be able to explain:

• Why pregnancy does not suppress the immune system completely but rather alters immune function.
• Why colostrum is often called the baby’s “first immunization.”
• Why IgG crosses the placenta but IgM generally does not.
• Why Rh-negative mothers receive Rho(D) immune globulin when indicated.
• Why breastfeeding helps protect infants from gastrointestinal and respiratory infections.
• Why newborns are especially susceptible to infection during the first months of life.

Things Worth Memorizing

• Difference between innate and adaptive immunity.
• IgG crosses the placenta.
• IgA is abundant in breast milk.
• Rh-negative mothers can become sensitized to Rh-positive fetal blood.
• Rh immune globulin prevents sensitization but does not treat established sensitization.
• The fetus is genetically distinct from the mother but is normally tolerated because of specialized immune adaptations at the maternal-fetal interface.

Questions I Should Answer Without Looking

1. What is the difference between innate and adaptive immunity?
2. Which antibody crosses the placenta?
3. Which antibody is most important in breast milk?
4. Why isn’t the fetus rejected by the maternal immune system?
5. What is Rh sensitization?
6. When is Rho(D) immune globulin given?
7. Why are newborns more susceptible to infection?
8. How does breastfeeding support the infant’s immune system?
9. What is passive immunity?
10. Why is maternal vaccination sometimes recommended during pregnancy?

Compendium Entry

This chapter would become four pages in your Midwifery Compendium.

Page 1 – Immune System Overview

• Innate vs. adaptive immunity
• Major immune cells
• Antibody overview

Page 2 – Pregnancy & Immunity

• Maternal immune adaptations
• Maternal-fetal tolerance
• Placental immune function
• Passive immunity

Page 3 – Rh Disease

Include:

• Rh factor
• Sensitization process
• Hemolytic disease of the fetus/newborn
• Prevention with Rho(D) immune globulin

Page 4 – Newborn Immunity

• IgG transfer during pregnancy
• Colostrum and IgA
• Immune immaturity
• Breastfeeding and infection protection

Quick Reference Cards

This chapter naturally lends itself to several cards:

• Innate vs. Adaptive Immunity
• Immunoglobulins (IgG, IgA, IgM, IgE, IgD)
• Maternal-Fetal Immune Tolerance
• Rh Sensitization
• Rho(D) Immune Globulin
• Hemolytic Disease of the Fetus and Newborn
• Passive Immunity
• Colostrum
• Breast Milk Immunology
• Neonatal Immune Development

One study technique I’d recommend

Think of this chapter as answering four key questions that you’ll encounter repeatedly in practice:

A practical pearl

As you build your compendium, consider linking this chapter to earlier ones:

• Chapter 8 (Placenta): Add a note that one of the placenta’s key functions is immune regulation and IgG transfer.
• Chapter 6 (Fertilization): Note that the embryo implants without being rejected by the maternal immune system.
• Newborn Care: Reference this chapter whenever discussing breastfeeding, neonatal infections, or vaccination.

These cross-references will help you see immunology not as an isolated subject but as a theme that runs throughout pregnancy, birth, and the postpartum period.