637 4060 ADDRESS: 60 Mount Street Lower, Grand Canal Dock, Dublin 2 info@merrionultrasound.ie

Pregnancy And Chickenpox – Learn About The Causes And Find Out What You Can Do

Chicken pox is not a common concern during pregnancy but did you know that having a chicken pox during this period can also cause harm to your baby? Chicken pox is said to be very rare during pregnancy. In the United Kingdom, research shows that it affects 3 in every 1000 pregnant women which is equivalent to 0.3% only. Furthermore, over 90% of pregnant women are immune to chicken pox since they had it during childhood.

Chicken Pox during Pregnancy

Chicken pox is a viral infection which is normally caused by a varicella virus. When infected during pregnancy, it can cause several complications both to the mother and the baby. The risks involved actually depend on the time of infection.

Pregnant women who have a history of chicken pox, or those who had taken a chicken pox immunization should be less worried. According to research, 80­90% of these women contain antibodies which make them immune against chicken pox. Exposure to people infected with chicken pox during pregnancy should not even cause you a worry.

Chicken Pox Immunization

Chicken pox vaccines are not given to pregnant women. This is why most doctors recommend taking chicken pox vaccine a month before conception. The administration of chicken pox vaccine is considered safe when breastfeeding.

A single dose of chicken pox vaccine is said to be effective in preventing 80­85% of all chicken pox severe cases. The Center of Disease Control (CDC) is now recommending two doses of chicken pox vaccine as they provide maximum benefits in protecting the body against the invasion of varicella virus and chicken pox infection.

Chickenpox pregnancy

Risks Associated with Chicken Pox during Pregnancy

Chicken pox is said to occur to 0.5­0.7% of pregnancies. While most pregnant women have immunity against varicella virus, the unfortunate ones who do not have antibodies are at a greater risk for varicella pneumonia. It is a condition of the lungs which is considered as life­threatening. Chicken pox also increases the mother’s risk for miscarriage and even foetal death.

On the other hand, chicken pox infection occurring during first trimester of pregnancy, especially from the 8th­12th week, puts the baby at a greater risk for congenital varicella syndrome. It is a syndrome of birth defects that occur in infants.

A baby with congenital varicella syndrome may grow poorly in the uterus. Later on, the baby may suffer from mental and physical developmental disabilities. This disease is commonly represented by skin scarring. Other manifestations include small limbs, low birth weight, small head, eye problems and mental retardation.

Furthermore, research shows that chicken pox may cause foetal varicella syndrome (FVS) in 1­2% of the babies born. FVS can actually cause significant damage on the baby’s arms, legs, eyes, bowel, bladder and brain.

Chicken Pox on the Third Trimester of Pregnancy

Having a chicken pox on the third trimester of your pregnancy is not at all dangerous to your baby. If chicken pox comes 5­21 days before your delivery, it can be beneficial to your baby. Five days after you first had your chicken pox, your body produces antibodies which are passed to your baby through the placenta.

However, if chicken pox strikes about 5 days before and 2 days after the delivery, it can be dangerous to your baby. Your body may be able to produce antibodies against the virus however, your baby doesn’t have enough time to absorb these antibodies.

While most pregnant women are not highly susceptible to chicken pox due to vaccine which gives them immunity, research shows that getting a chicken pox 2 days after and 5 days before the delivery date exposes the baby to a greater risk for a disseminated varicella infection.

There is a 17­30% probability that the baby would develop a condition known as neonatal varicella which can really be life­threatening and serious when left untreated. To prevent severe cases of this condition, infants are normally given with a shot of varicella zoster immune globulin, a blood product containing chicken pox antibodies.

Women who had chicken pox on or after the 36th week of pregnancy are most likely to give birth to babies with chicken pox.

Complications of Chicken Pox during Pregnancy

The complications of chicken pox in pregnant women are at the highest if these women are smoking and are over 20 weeks pregnant. Women who have taken steroids for the past three months as well as those who have been diagnosed with lung conditions such as emphysema and bronchitis are at the greatest risks.

Getting a chicken pox on the third trimester of your pregnancy can be life threatening to pregnant women. It increases women’s risk for chicken pox pneumonia which is a major risk factor for preterm delivery. Cigarette smoking during this period also increases one’s risk for preterm delivery.

Aside from pneumonia, chicken pox also increases the pregnant women’s risk for the inflammation of the brain (encephalitis), heart muscles (myocarditis), appendix (appendicitis), pancreas (pancreatitis), liver (hepatitis) and kidneys (glomerulonephritis).

What Should You Do When Symptoms of Chicken Pox Occurs

Whenever you notice the existence of chicken pox symptoms, you should call a doctor immediately. Pregnant women are strongly recommended to get appointments instead of showing up to the doctor’s clinic immediately as they can infect other pregnant women also.

When diagnosed with chicken pox, pregnant women are normally prescribed with acyclovir, which is an antiviral drug. When symptoms of pneumonia begin to occur, call your doctor’s attention immediately as it can worsen your condition very rapidly. These symptoms of pneumonia include coughing, discomfort when breathing and rapid breathing.

How to Reduce Your Risk for Chicken Pox during Pregnancy

If you are not sure about your immunity to varicella virus, it will always be best to avoid people who have been recently infected by chicken pox. As much as possible, try not to get in touch with people who were not yet immune but have come in contact with infected people for the past three weeks. Avoid anyone who has shingles or those who have experienced some flu­like symptoms recently.


Nuchal Translucency

12-14 weeks


Anatomy Survey

21-22 weeks


Later Dating

10-17 weeks


Gender Scan

19 weeks onwards


Growth & Well Being

22 weeks onwards


Post Dates & Liquor

40 weeks onwards


About The Clinic

Merrion Fetal Health Pregnancy Scans Dublin 2

About The Consultants

Dr. Rhona Mahony

About The Team

Pregnancy scans lead sonographer at Merrion Fetal Health

Book Your Scan

Screen of Pregnancy Scan

Common Concerns

FAQs - Your Questions


GP Referral Scheme


Health Conditions


Healthy Pregnancy


Medical Studies


Patients' Information


Pregnancy Diary


Pregnancy Magazines

pregnancy health magazines

Scans & Services

18 weeks pregnancy scan facial profile Merrion Fetal Health

Susan's Trimesters

pregnancy trimesters

Videos By Consultants


Midwife sonographer facilitated

Consultant Led, Centre of Medical Excellence 


All articles on the blog and website are intended as information only. Please do not consider any of the information provided here as a substitute for medical advice. At all times seek medical advice directly with your own doctor and medical team.


This website was formerly Merrion Fetal Health. The clinic has undergone a rebrand and is now known as Merrion Ultrasound.