Tuesday, May 21, 2013

Herpes Simplex - Risk Factors

Complications


The severity of symptoms depends on where and how the virus enters the body. Except in very rare instances and in special circumstances, the disease is not life threatening, although it can be very debilitating and cause emotional distress.

Herpes and Pregnancy

Pregnant women who have genital herpes due to either herpes simplex virus 2 (HSV-2) or herpes simplex virus 1 (HSV-1) have an increased risk for miscarriage, premature labor, retarded fetal growth, or transmission of the herpes infection to the infant either in the uterus or at the time of delivery. Herpes in newborn babies (neonatals) can be a very serious condition.

Fortunately, neonatal herpes is rare. Although about 25 - 30% of pregnant women have genital herpes, less than 0.1% of babies are born with neonatal herpes. The baby is at greatest risk during a vaginal delivery, especially if the mother has an asymptomatic infection that was first introduced late in the pregnancy. In such cases, 30 - 50% of newborns become infected. Recurring herpes or a first infection that is acquired early in the pregnancy pose a much lower risk to the infant.

The reasons for the higher risk with a late primary infection are:

  • During a first infection, the virus is shed for longer periods, and more viral particles are excreted.
  • An infection that first occurs in the late term does not allow the mother time to develop antibodies that would help her baby fight off the infection at the time of delivery.

The risk for transmission also increases if infants with infected mothers are born prematurely, if there is invasive monitoring, or if instruments are used during vaginal delivery. Transmission can occur if the amniotic membrane of an infected woman ruptures prematurely, or as the infant passes through an infected birth canal. This increased risk is present if the woman is having or has recently had an active herpes outbreak in the genital area.

Very rarely, the virus is transmitted across the placenta, a form of the infection known as congenital herpes. Also rarely, newborns may contract herpes during the first weeks of life from being kissed by someone with a herpes cold sore.

Congenital herpes

Review Date: 11/05/2010
Reviewed By: Harvey Simon, MD, Editor-in-Chief, Associate Professor of Medicine, Harvard Medical School; Physician, Massachusetts General Hospital. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc.

A.D.A.M., Inc. is accredited by URAC, also known as the American Accreditation HealthCare Commission (www.urac.org)