Pregnancy Increases Risk for Tuberculosis

TB rates higher for pregnant and postpartum women

/ Author:  / Reviewed by: Joseph V. Madia, MD

(RxWiki News) Tuberculosis (TB) is a contagious bacterial infection that affects your lungs. It’s not very common in the U.S., only affecting about 11,000 Americans yearly. But there’s one group that may be more susceptible to TB: pregnant women.

A British study reports that women are more likely to be diagnosed with TB in the six months after pregnancy, compared to women who haven’t been pregnant. But the study cautions that there’s a good chance the condition developed during pregnancy, making pregnant women at increased risk as well.

"High-risk pregnant women should be screened for TB."

Researchers from the UK’s Health Protection Agency and the University of East Anglia tracked 264,136 pregnancies between 1996 and 2008. The aim of the study was to see if there was a greater risk for TB during pregnancy and immediately after (postpartum). They compared the rate of TB in pregnant women against the rate of TB in women who had given birth within six months. The team also looked at the rate of TB in women who hadn’t been pregnant.

There were 177 cases of TB among the women; 22 of these women were pregnant and 22 were postpartum. According to the researchers, the rate for developing TB in the combined group of pregnant and postpartum women was 15.4 per 100,000 person years. For women who weren’t pregnant, the rate is lower at just 9.1 per 100,000 person years. The researchers adjusted the rates by taking into account each woman’s age, geographic region and socioeconomic status and found that women who were in the six-month period following pregnancy were more likely to have TB.

Still, it seems likely that the risk during pregnancy must be increased too, said Dr. Dominik Zenner, consultant in public health at the Respiratory Diseases Department at the Health Protection Agency in a press release.

The team said that a woman may gradually become more susceptible to TB during pregnancy (because of her weakened immune system), and that a diagnosis could be given much later, when she is postpartum, after the condition developed during pregnancy. This explains why diagnoses of TB were lower during pregnancy compared to the six months after delivery.

Dr. Zenner recommends that pregnant and postpartum women in high-risk groups should be screened for TB.

According to the Centers for Disease Control and Prevention, high-risk groups include women with weakened immune systems – for example, due to AIDS, chemotherapy, diabetes or certain medications – and women who have poor nutrition or live in crowded or unsanitary living conditions. Women who travel to countries that have high rates of TB, or who are otherwise in contact with TB-infected people, are also at risk.

Most people’s bodies are able to fight off TB bacteria if infection occurs. If a person has latent TB infection, he or she will not have any symptoms and cannot spread the bacteria to others. However, if the TB bacteria becomes “active” and multiplies, he or she will develop TB disease, sometimes years later.

The disease can be fatal if it’s not treated properly with several drugs over a six to twelve month period.

This observational study was published in the American Thoracic Society’s American Journal of Respiratory and Critical Care Medicine.

Reviewed by: 
Review Date: 
December 12, 2011
Last Updated:
December 14, 2011