pharmasites logo
We use cookies to enhance your browsing experience. By clicking 'I Understand and Accept', you consent to our use of cookies.
I understand and accept
No, I don't want to use cookies
My Account
Control Panel
An example toast message
Do Something
Login
en
en
Pharmasites logo.
Menu
en
en
Change Language
Login
My Account
Control Panel
Free Upgrade
What You Get
Pricing
About Us
Contact Us
Book a Chat
Log Out
Login
Login
en
en
Do Something
Login
en
en
Pharmasites logo.
Menu
en
en
Change Language
Login
My Account
Control Panel
Free Upgrade
What You Get
Pricing
About Us
Contact Us
Book a Chat
Log Out
Login
Login
en
en
Causes

Rhesus disease is caused by a specific mix of blood types between a pregnant mother and her unborn baby.

It can only occur where all of the following happen, where the:

  • mother has a rhesus negative (RhD negative) blood type
  • baby has a rhesus positive (RhD positive) blood type
  • mother has previously been exposed to RhD positive blood and has developed an immune response to it (known as sensitisation)
Blood types

There are several different types of human blood, known as blood groups, with the 4 main ones being A, B, AB and O. Each of these blood groups can either be RhD positive or negative.

Whether someone is RhD positive or RhD negative is determined by the presence of the rhesus D (RhD) antigen. This is a molecule found on the surface of red blood cells.

People who have the RhD antigen are RhD positive, and those without it are RhD negative. In the UK, around 85% of the population are RhD positive.

How blood types are inherited

Your blood type depends on the genes you inherit from your parents. Whether you're RhD positive or negative depends on how many copies of the RhD antigen you've inherited. You can inherit one copy of the RhD antigen from your mother or father, a copy from both of them, or none at all.

You'll only have RhD negative blood if you don't inherit any copies of the RhD antigen from your parents.

A woman with RhD negative blood can have an RhD positive baby if her partner's blood type is RhD positive. If the father has two copies of the RhD antigen, every baby will have RhD positive blood. If the father only has one copy of the RhD antigen, there's a 50% chance of the baby being RhD positive.

Sensitisation

An RhD positive baby will only have rhesus disease if their RhD negative mother has been sensitised to RhD positive blood. Sensitisation occurs when the mother is exposed to RhD positive blood for the first time and develops an immune response to it.

During the immune response, the woman's body recognises that the RhD positive blood cells are foreign and creates antibodies to destroy them.

In most cases, these antibodies aren't produced quickly enough to harm a baby during the mother's first pregnancy. Instead, any RhD positive babies the mother has in the future are most at risk.

How does sensitisation occur?

During pregnancy, sensitisation can happen if:

  • small numbers of foetal blood cells cross into the mother's blood
  • the mother is exposed to her baby's blood during delivery
  • there's been bleeding during the pregnancy
  • an invasive procedure has been necessary during pregnancy – such as amniocentesis, or chorionic villus sampling (CVS)
  • the mother injures her abdomen (tummy)

Sensitisation can also occur after a previous miscarriage or ectopic pregnancy, or if a RhD negative woman has received a transfusion of RhD positive blood by mistake (although this is extremely rare).

How sensitisation leads to rhesus disease

If sensitisation occurs, the next time the woman is exposed to RhD positive blood her body will produce antibodies immediately.

If she's pregnant with an RhD positive baby, the antibodies can lead to rhesus disease when they cross the placenta and start attacking the baby's red blood cells.

Last Reviewed
03 December 2021
NHS websiteNHS website
Pharmasites footer logo.
Store Hours Unavailable
No store selected for opening hours
Loading Open Hours...
With over a decade's experience working with UK pharmacies and supplying software that manages over 1,500 UK pharmacy websites, you're in safe hands with Pharmasites. Get in touch today!
Menu
Home
Free Upgrade
Pricing
Referrer Rewards
About Us
Contact Us
Book a Chat
Features
Easy Website Updates
Interactive Maps
Book NHS & Private Services
Pharmacy First
eCommerce
Built-in NHS A-Z
NHS App Integration
See more features
Pharmasites
11 Anderson Way, Lea, Gainsborough, Lincolnshire, DN21 5EF
matt@pharmasites.co.uk
01904 349 316
No store selected for contacts
No contacts at this store
Pharmasites © 2024
Cookies Policy
Privacy Policy
Terms and Conditions