Perinatal HIV Transmission and Birth Options for HIV-Positive Mothers

HIV Treatment Series II: Part Two of Four

Many people are misinformed about the risks of perinatal HIV transmission, including many healthcare providers. Some people mistakenly believe that all babies born to HIV-positive women will be infected, or that HIV-positive women are too sick to have healthy pregnancies and give birth to healthy children. Many people also don't know that there are ways to greatly reduce the risk of mother-to-child HIV transmission. About 25% of children born to HIV-positive women who receive no treatment or interventions against perinatal HIV transmission become infected with HIV -- that means an average of 25 out of 100 babies, or 1 in 4, can pick up HIV from their mothers during pregnancy, birth, or afterward from breastfeeding. But perinatal HIV infection rates can drop to as low as 1% or 2% for babies whose mothers are able to use combination antiretroviral therapy during pregnancy, AZT or nevirapine prophylaxis during labor and after birth, and choose the birth option that's safest, according to maternal viral load levels, for both mother and baby.

You are a good place for your baby to grow, and you deserve respectful care. If your HIV care specialist or prenatal care provider tries to dissuade you from becoming pregnant or recommends you terminate a wanted pregnancy, get another provider! With good care and support, your risk of transmitting HIV to your fetus or baby is very low. Don't let that worry stop you if you want to be a mother.

How Perinatal HIV Transmission Happens

A fetus (your baby from 8 weeks gestation until birth) or newborn can become infected with HIV through contact with virus in their mother's blood, cervical and vaginal secretions, and breast milk. It's the mom's HIV status that matters, not the father's -- HIV transmission to babies is all about the virus in their mom's fluids, not in their father's semen. If the mom stays HIV negative throughout her pregnancy, there's no risk to the baby even if the father is HIV positive.

No one knows the exact mechanisms involved in perinatal transmission, but it's believed to occur three different ways:

Prenatally (in utero): Some babies acquire HIV because the virus crossed the placenta during pregnancy -- this doesn't happen very often, but it can. During pregnancy, the mother's blood supply is connected to the fetal blood supply via the umbilical cord and placenta. The mother and the baby do not share the same blood supply, but sometimes HIV in the mother's blood is able to cross the placenta and infect the baby. The following conditions can increase the risk of transmission during gestation:

  • Becoming infected with HIV during pregnancy. A person's viral load is very high right after they acquire the virus, and a high viral load increases the transmission risk to the fetus.

  • Infections of the chorion, amniotic membranes, or reproductive tract. Sexually-transmitted vaginal infections like chlamydia, gonorrhea, and trichomoniasis can cause a spike in the pregnant woman's viral load, which can in turn increase the risk of transmission to her fetus.

  • Placenta Previa. This is when the placenta grows over part or all of the cervix -- a condition that can lead to heavy bleeding before or during labor. Placenta previa often corrects itself as the uterus expands during pregnancy.

At birth: During labor and delivery, the baby comes into contact with her/his mother's blood and cervical/vaginal secretions while passing through the cervix and vagina. Research indicates that the majority of babies who pick up HIV infection from their mothers probably acquire the virus during the birth process.

During breastfeeding: There have been several documented cases in which HIV has been transmitted through breastfeeding. HIV has been isolated in breast milk, and the documented cases of transmission through breastfeeding indicate that the virus was passed through the milk rather than during gestation or the birth process. Blood from cracked nipples or breast infection (mastitis) may also be present during breastfeeding, and may contribute to the risk of infection.

The risk of perinatal transmission risk at any stage can be greatly reduced by:

  1. Taking combination therapy during pregnancy to reduce maternal viral load.

  2. Taking AZT during labor and birth to help protect the baby while it's exposed to HIV in blood and cervical secretions.

  3. Choosing the birth option that poses the least risk to both mother and baby -- a normal vaginal birth, or an elective cesarean section (surgical birth).

  4. Administering AZT to the newborn for up to six weeks after birth.

  5. Bottle-feeding formula or breast milk from a milk bank instead of breastfeeding or bottle-feeding your baby your own breast milk.

Prenatal Care

You'll receive the same prenatal care as an HIV-negative woman, except for a few instances. You'll be working either with a prenatal healthcare provider who is also an HIV specialist, or with an obstetrician in addition to your regular HIV specialist.

During prenatal care, your OB should avoid the following tests and procedures unless they are considered medically necessary, because they are invasive and may increase the risk of HIV transmission to your fetus during pregnancy:

Amniocentesis: a diagnostic test for chromosomal abnormalities like neural tube defects and Down's syndrome. It involves inserting a long, very thin needle through your abdomen and into your uterus to obtain a sample of amniotic fluid. Another screening method that checks for alfa fetal protein (AFP) levels in a blood sample can be done instead.

Chorionic villi sampling (CVS): taking a sample of the chorionic villi, tissue which will form the placenta. This is another way to check for chromosomal abnormalities, but because it disturbs the placental site and causes some bleeding, it's not as safe for your fetus as AFP testing.

Your provider may also want to perform more ultrasounds (visualizing the fetus in the uterus) than they would for a woman without HIV, especially if there is a question about your fetus's gestational age due to irregular menstration. If this bothers you, talk with your provider about how to keep ultrasound use at a minimum while still getting information that will help you both decide when an elective cesarean section can be done safely if you decide to give birth via C-section.

Use of Combination Therapy for Controlling Maternal HIV Infection

Combination antiretroviral therapy (also called Highly Active Antiretroviral Therapy, or HAART) is recommended for use during pregnancy regardless of a woman's CD4 count or viral load. Using combination therapy between 14 and 34 weeks in pregnancy can be helpful in reducing your viral load, which in turn helps reduce the risk of transmission to the fetus during gestation and also during labor and birth. You can work with your HIV specialist to choose a regimen from among the drugs recommended for non-pregnant adults. Your HIV specialist may suggest a regimen that includes AZT. If you are resistant to AZT or have experienced toxicity with past use, be sure to tell your provider.

Avoid Sustiva! It's not recommended for use at any time during pregnancy due to risk of birth defects. If you find out you're pregnant while using Sustiva, don't panic! Just consult your HIV specialist and change your regimen for the remainder of your pregnancy. If Sustiva is working well for you, you should be able to go back to it again after your baby is born.

For your own safety, you should also avoid using the following meds in combination with each other during pregnancy:

  • d4T (Zerit) + ddI (Videx)
    Can cause serious and potentially fatal lactic acidosis.

  • AZT (zidovudine) + d4T (Zerit)
    These don't react well together pharmacologically. If you're taking Zerit as part of your regular HAART regimen, talk with your provider about substituting it altogether for the duration of your pregnancy, or stopping it during labor and delivery so you can safely use AZT prophylaxis.

If you're already on combination therapy when you become pregnant, most healthcare providers will recommend that you stay on your regimen during the first trimester of pregnancy unless you're too nauseous to keep your meds down. Pregnancy-related nausea and vomiting ("morning sickness") tends to be worst during the first trimester for women who experience it -- puking up your pills isn't helpful, so for some women it's safer to stop meds until morning sickness subsides. If you decide to take a break from your meds, all drugs should be stopped at the same time and then re-started at the same time in order to reduce the risk of developing resistance (consult your physician).

If you've never used combination therapy before, many providers will recommend waiting until after 12-14 weeks of pregnancy, unless your viral load is very high or your health would benefit from starting combination therapy right away. There are two reasons for this recommendation: 1) to avoid potential side effects such as nausea/vomiting and diarrhea at the same time you may be struggling with morning sickness, and 2) because the risk of medication-related birth defects (for any medication, not just antiretrovirals) is considered highest in the first trimester, when the fetal organ and skeletal systems are forming. However, a woman cannot be denied therapy at any time during a pregnancy -- if you want it, you should be given it.

AZT for Fetal Protection and Infant Prophylaxis

Even if you don't use any combination therapy during pregnancy, taking AZT during the birth process and administering it to the baby after birth will help to greatly reduce the risk of transmission. Remember, the studies that showed AZT to be effective in reducing perinatal transmission focused on the use of drugs during labor and given to the baby after birth -- that's where they found the reduction from 25% to 8%. Use of AZT and other meds during pregnancy can help reduce the risk even more (down to as low as 1%), but it's almost never too late to do something until 24 to 48 hours after the baby is born.

AZT is currently the standard prophylactic treatment against perinatal transmission used in the United States. If you use AZT during labor and birth, it will be administered to you through an IV regardless of whether you give birth vaginally or by elective C-section. After birth, your baby will be given AZT syrup within 8 to 12 hours, and you'll be shown how to give the syrup yourself at home for the next six weeks.

HAART and Child Safety

It's totally understandable if you're worried about what effect these powerful antiretrovirals may have on your fetus or baby. Fortunately, studies conducted by research entities such as the Antiretroviral Pregnancy Registry are indicating that children born to mothers who have used antiretroviral medications during pregnancy do not appear to be statistically at higher risk for birth defects than babies born to mothers who didn't use HAART. The preliminary results for the study following the children who were born to women who participated in ACTG 076 (the study that demonstrated AZT's effectiveness in reducing perinatal transmission) show that, after 6 years, these children do not appear to be experiencing a greater degree of health problems than are noted in the general population of children. However, we can't yet know the long-term outcomes for children born to women who used combination therapy during pregnancy and/or AZT prophylaxis. Research is being conducted continuously, though, so we're getting more and more information as time goes on.

No one can force you to take meds while pregnant. If you don't want to or can't take meds during your pregnancy, you cannot legally be made to take any medication on behalf of yourself or your fetus. Right now, the use of AZT and other antiretroviral medications in pregnancy is recommended because the known risks of pediatric AIDS are thought to outweigh the unknown possible long-term risks of their use during pregnancy for both mother and child. If you have concerns about the effect AZT or other meds may have on your child, now or in the future, discuss them with your healthcare provider, HIV/OB specialist, or a local agency that advocates for HIV-positive people. The information in these links may also be useful to you:

Options for Birth

If your viral load is less than 1,000 copies/ml, there is currently no evidence showing that elective cesarean section will reduce the risk of perinatal HIV transmission. C-section is major abdominal surgery -- you want to avoid it unless it's considered beneficial to you or your baby, because of the increased risk of post-operative complications in mothers who give birth by C-section. Women with viral loads under 1,000 can consider a normal vaginal birth to be the safest option for both them and their baby, unless there are other factors (baby in difficult position for birth, obstetric emergency, etc.) that necessitate C-section.

To reduce tissue damage, extra bleeding, and infection risk during vaginal birth, your care provider will avoid the following invasive procedures and use of instruments unless medically indicated:

  • Artificial Rupture of Membranes (AROM -- "breaking your water" with a small instrument that looks like a crochet hook). When your bag is intact, your baby remains protected by the amniotic fluid and membranes that form a barrier between it and virus in your blood and cervical secretions. Maintaining that protection for as long as possible reduces the risk of HIV transmission to your baby.

  • Multiple vaginal exams after membranes have ruptured. Vaginal exams are generally done to check for progress in labor. Because there's an increased risk of bacterial infection each time an exam is done, these exams will be kept to a minimum after your water breaks.

  • Internal fetal monitors and fetal scalp tests. These cause small cuts in the baby's scalp, which would then be exposed to HIV in the mom's fluids.

  • Episiotomy (a surgical incision to enlarge the vaginal opening). Episiotomies always cause bleeding, increasing the amount of blood your baby is exposed to as it's being born.

  • Instruments like forceps or vacuum extractors that necessitate episiotomies and/or can cause vaginal tears and bleeding.

If your viral load is over 1,000 copies/ml, research shows that elective cesarean section done prior to rupture of membranes can reduce the risk of HIV transmission by preventing contact between the fetus and the blood and cervical secretions that are present during the birth process ("elective" means you choose to do it, rather than have it done for emergency reasons). C-section after the membranes have been ruptured for at least four hours has not shown to be statistically helpful in reducing HIV transmission, so elective C-sections done to reduce HIV transmission are usually performed at 38 weeks gestation (well before most women's water breaks on its own). Because of the increased risk of post-operative infections in women who give birth by C-section, your care provider may give you antibiotics to take after the surgery.

The choice of how to give birth is ultimately yours. Your healthcare provider should discuss your options with you and provide their professional opinion based on your lab tests and overall health of both you and your fetus, but you are still the person who makes the final decision.

What About Breastfeeding?

Because there are documented cases showing that HIV can be transmitted from mother to infant through breastfeeding, HIV-positive women are counseled to avoid breastfeeding if safe alternatives to breastfeeding exist. If you don't want to feed your baby formula, you can try to find a milk bank (an organization that collects donated breastmilk and ships it out) in your area and use that instead. For more information on this option, call Human Milk Banking Association of North America, Inc. at (919) 861-4530 or on the Internet at

HIV-positive women living in places where clean water and consistent supplies of safe formulas are not available need to weigh the risks and benefits of breastfeeding their babies. If their children are at high risk for starvation, dehydration, and diarrhea associated with unsafe formula-feeding, breastfeeding may be the safer alternative even though it increases the risk of HIV transmission to the baby. In the U.S. and Canada, HIV-positive women are largely able to safely formula-feed, and are therefore encouraged to do so. If you live in the United States and are considered "low income", please know that you should also qualify for Medicaid and WIC supplements that provide free infant formula (regardless of your immigration status, if that's a concern). In many places, services may be prioritized for HIV-positive mothers, so ask your healthcare provider or case manager for more information.


Preventing transmission of HIV to your baby is one very important aspect of your care, but it shouldn't be the only focus. Your physical and emotional health are important for your own sake, too -- and taking care of yourself is taking care of your baby! Aside from HIV infection, you're just like any other pregnant woman. Your provider should respect your decision to become pregnant and have a baby, and should assist you in having the healthiest and happiest pregnancy you can have. You and your baby deserve nothing less. Congrats, and good luck!

Note: This article was written with assistance from the Pediatric AIDS Chicago Prevention Initiative (PACPI). For more information on PACPI's Chicago-area services and classes for HIV-positive pregnant women, call (773) 327-0509. Clinicians and social service providers can call the 24-hour hotline at (312) 926-7380. Thanks to Anne and Brenda!


  1. Recommendations for Use of Antiretroviral Drugs in Pregnant HIV-1 Infected Women for Maternal Health and Interventions to Reduce Perinatal HIV-1 Transmission in the United States, 8/30/2002.

  2. American College of Obstetrics and Gynecology Committee Opinion Number 234, 5/00: Scheduled Cesarean Delivery and the Prevention of Vertical Transmission of HIV Infection.

  3. Anderson, Jean R., M.D. "Cesarean Section and Perinatal Transmission" -- The Johns Hopkins HIV Report 5/99.

  4. Elliott, Richard. Policy & Research of the Canadian HIV/AIDS Legal Network. Volume 5, Number 1, Fall/Winter 1999: HIV Testing & Treatment of Children -- Canadian HIV/AIDS Policy & Law Newsletter.

  5. Guidelines for the Use of Antiretroviral Agents in HIV-1-Infected Adults and Adolescents, 7/14/2003.

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