Risk of Deformities Very Low in Infants Exposed to HAART

Like their counterparts in France, researchers in the United Kingdom have been monitoring the health of children born to HIV positive women. In particular, they have focused their analysis on birth defects. Their results suggest that birth defects are not increased because of exposure to HAART.

Study Details

The study team reviewed data on 8, 242 infants, 232 of whom had at least one birth defect.

Results -- Timing

In the first three months after conception, moving from fertilized egg to fetus, development and growth is extremely rapid. During this time, because of such rapid growth the fetus is exquisitely sensitive to the effects of drugs. So British researchers focused on whether initiating HAART during the first trimester was associated with an increased risk of birth defects compared to other trimesters.

When they took into account maternal factors such as substance use, ethnicity, age and health, there was no significant difference in the risk of birth defects among women initiating HAART in different trimesters.

Different Drug Classes

No particular family or class of anti-HIV drugs was associated with an increased risk of birth defects.

Individual Drugs

Based on studies in monkeys, efavirenz (Sustiva, and in Atripla) can cause severe birth defects. In the UK study, a total of 220 infants were exposed to efavirenz in the womb. Slightly more than 2% (five infants) developed birth defects, including the following:

  • undescended testicles
  • dislocated hips
  • deformed intestines

But the rate of these birth defects was similar to that seen in children born to HIV negative women who did not take efavirenz.

A similar trend was seen with ddI in that whatever defects occurred were seen at the same rate in children born to HIV negative women.

In General

The most commonly reported birth defects affected the following body parts:

  • muscle and skeleton
  • limb
  • heart and circulatory system
  • genitals


In boys born to HIV negative mothers, a relatively common birth defect, occurring in 1 in 150 or 1 in 300 boys depending on where the study was done, is hypospadias. In this condition, the penis looks abnormal and the opening that is normally at the tip is located somewhere else, usually near the head of the penis. But in a small proportion of cases, this opening can occur on the underside of the penile shaft or even near the scrotum. Hypospadias can be corrected with surgery. There were 12 cases of hypospadias in the British study, all occurring in children exposed to AZT in the womb. However, this finding does not prove that AZT causes hypospadias. A formal clinical trial would be needed to resolve that issue.


The rate of birth defects was nearly 3% in the UK study. In children born to HIV negative women in the UK, the rate is between 2% and 3%. On the European continent, the rate is 2.2%. The results of the British study should reassure HIV positive women who are thinking of having a baby that the use of HAART does not pose a major risk for birth defects.


  1. Anderson BL, Cu-Uvin S. Pregnancy and optimal care of HIV-infected patients. Clinical Infectious Diseases. 2009; in press.
  2. Townsend CL, Willey BA, Cortina-Borja M, et al. Antiretroviral therapy and congenital abnormalities in infants born to HIV-infected women in the UK and Ireland, 1990?2007. AIDS. 2009; in press.

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