Resistance

Should I have a resistance test?
Will I need extra tests and monitoring?
Are there any tests that I should not have?
OI prevention and treatment during pregnancy
Vaccine use while pregnant
Treating recurrent genital herpes during pregnancy
HIV and hepatitis coinfection
HIV and TB co-infection

Mum and doctor Drug resistance is an important issue during pregnancy. Some strategies to reduce mother-to-child transmission can also easily lead to resistance.

Using only one drug (monotherapy) or two drugs (dual therapy) are not good options as the minimum treatment for an HIV-positive person. Therefore, neither of these should be used for HIV-positive women who are pregnant and require treatment for their own HIV. Of strategies for pregnant women who do not require treatment, AZT used alone is less likely to induce resistance than AZT plus 3TC or nevirapine alone.

What is drug resistance and how to avoid it

Mono and dual therapy

Monotherapy is using only one HIV drug and dual therapy uses two drugs. Neither strategy has been as effective as using 3 drugs for treating HIV. In some circumstances though, these strategies are still recommended for reducing mother-to-baby transmission.

If you are already using combination therapy and your viral load is not undetectable, it is important that you look at why this is occurring with an expert. This is very important for your own and your baby’s health.

Resistance can develop when your viral load is detectable. This will affect your long-term health. Viral load at time of delivery is also strongly linked with risk of transmission to your baby.

Taking a treatment break, if not managed properly, can lead to resistance. Not taking all your pills at the right time can also lead to resistance.

It is also possible to transmit resistant virus. A baby born with drug-resistant HIV virus is much harder to treat.

We explain drug resistance and how to avoid it, and include advice on adherence, in the i-Base booklet Introduction to Combination Therapy.

Should I have a resistance test?

Current British pregnancy guidelines recommend a resistance test if you are changing therapy. These guidelines are the same as for a “non-pregnant adult”. They also recommend a resistance test if you have just been diagnosed and if you are just starting therapy for the first time.

Women stopping HAART should have a resistance test on their first viral load after they stop treatment, ideally within 6 weeks. Women taking AZT monotherapy should have a resistance test on the viral load sample taken at delivery.

A resistance test is important to determine whether all the drugs in your combination will be active and working (both during pregnancy and in the future). It should be able to tell whether you were infected with resistant virus.

You should check that your doctor has included this test.