Once a common childhood illness, chicken pox is an infection caused by the varicella-zoster virus. At one time, approximately four million children in the U.S. contracted chickenpox each year and nearly 11,000 people were hospitalized. Because a vaccine now exists to prevent chicken pox, the number of cases and hospitalizations has declined.
When chicken pox does occur, it is a highly contagious illness and anyone who is not immune could catch the disease. Certain groups fall in high risk categories of developing complications from chickenpox including infants, teens, adults, pregnant women and anyone with a suppressed immune system.
If you have previously had chicken pox, the varicella-zoster virus can remain in your nerve cells and lie dormant for years. If the virus reactivates you can develop shingles, a painful band of blisters usually on your trunk. Estimates suggest that one in ten adults who have had chickenpox will have shingles at some point.
Pregnant women who develop chicken pox, especially in the first 20 weeks, can pass the illness on to the fetus, increasing the risks of complications and birth defects. When you contract chicken pox later in pregnancy or right before delivery, the newborn can face dangerous health complications. If you had chicken pox at any point prior to pregnancy, you are immune and will pass this immunity on to the baby through the placenta.