Having worked as a Teratogen Information Specialist at MotherToBaby for close to 10 years, I have become well versed in the different exposures people commonly ask about. Allergy medications in the spring, sunscreen and bug spray in the summer, and cough and cold medications all winter long. So, when I logged onto our live chat service at mothertobaby.org on a Tuesday morning, I was surprised to see a question that doesn’t come up very often. Natalie, pregnant with her first child, asked: “I’m 24 weeks pregnant and my midwife says I need a RhoGAM shot at my next appointment. What could happen to the baby if I do not get this shot?”

Blood Type Basics

Blood type is hereditary, which means it is passed down from your parents. There are 8 common blood types: A+, A-, B+, B-, O+, O-, AB+, and AB-. If your blood type ends in a minus sign (like A- or O-), you are Rh negative. If it ends in a plus sign (like A+ or B+), you are Rh positive. Most people in the United States are Rh positive, but about 15 out of every 100 people (15%) are Rh negative. A blood test early in pregnancy will tell you your blood type.

What is Rh Incompatibility?

During pregnancy, if a woman who is Rh negative is pregnant with a fetus that is Rh positive, a condition called Rh incompatibility can happen. Rh incompatibility becomes an issue if any of the Rh positive red blood cells from the fetus get into the mom’s Rh negative bloodstream. This is most likely to occur during a miscarriage, certain prenatal tests (like amniocentesis or CVS), a fall, labor and delivery, or if the placenta separates from the wall of the uterus. When this happens, the mom’s immune system might treat the fetus’ red blood cells as something that shouldn’t be in the body (like an infection) and start making antibodies against them. In most cases, these antibodies will not negatively affect the current pregnancy, but they might affect future pregnancies.

When Antibodies Attack

Once the mom’s body makes anti-Rh antibodies, they stay in her system for life. If she becomes pregnant again with another Rh positive fetus, the antibodies can cross the placenta and attack the fetus’ red blood cells. This can lead to a condition called hemolytic disease of the fetus and newborn (HDFN). Without enough red blood cells, the fetus cannot carry enough oxygen during development and complications such as jaundice (yellowing of skin and eyes), hemolytic anemic (low red blood cell count), hydrops fetalis (fluid buildup in the baby), high bilirubin levels, kernicterus (brain damage from the bilirubin), and even death can occur.

RhoGAM to the Rescue

Fortunately, there is a way to lower the chance of HDFN: The RhoGAM shot. Typically given around 28 weeks of pregnancy (and again within 72 hours of birth if the baby is confirmed to be Rh positive), RhoGAM is an antibody that helps stop the Rh negative mom from making antibodies that could attack a future fetus’ red blood cells and cause HDFN. Before RhoGAM was available, thousands of babies died from the condition every year. Nowadays, the chance of HDFN is less than 0.1% when the shot is given, making RhoGAM a remarkable intervention.

Protecting Your Future Babies

After sharing this information with Natalie, I summarized our conversation with a quick recap. Since she is Rh negative, her midwife was recommending a RhoGAM shot at 28 weeks to prevent the development of antibodies that could negatively affect a future pregnancy. An increased risk for miscarriage or birth defects is not expected since the shot is given later in pregnancy and Natalie is past the “critical period” for those outcomes to occur. Pregnancy complications, like preterm delivery and low birth weight, have not been reported in the available studies examining the use of RhoGAM in pregnancy. Natalie felt reassured after receiving this information and decided to proceed with the RhoGAM shot at her next midwife appointment.

If you have questions about the RhoGAM shot or any other exposures in pregnancy, please feel free to reach out to MotherToBaby by phone, chat, text, or email to receive evidence-based information that can help you make an informed decision.

References:

• American Red Cross. Facts About Blood and Blood Types. American Red Cross. https://www.redcrossblood.org/donate-blood/blood-types.html. Published 2025. Accessed April 29, 2025.

• Bowman J. Thirty-five years of Rh prophylaxis. Transfusion. 2003;43(12):1661-1666. doi:10.1111/j.0041-1132.2003.00632.x

• Hematology: Vaccinating the Rh-Negative. Time Magazine. June 21, 1968. https://time.com/archive/6636313/hematology-vaccinating-the-rh-negative/. Accessed April 30, 2025.

• The American College of Obstetricians and Gynecologists. The Rh Factor: How It Can Affect Your Pregnancy. https://www.acog.org/womens-health/faqs/the-rh-factor-how-it-can-affect-your-pregnancy. Published 2024. Accessed April 29, 2025.

• Yoham AL, Casadesus D. Rho(D) Immune Globulin. In: StatPearls [Internet]. Treasure Island, FL: StatPearls Publishing; 2025 Jan. Updated May 22, 2023. https://www.ncbi.nlm.nih.gov/books/NBK557884/. Accessed April 28, 2025.

It was late on a Tuesday when a chat came in from Dr. Rodriguez. “My patient is taking a medication for epilepsy. She is planning a pregnancy and I’ve seen from some sources she may need to take more folic acid to help prevent birth defects. Does she need to be on a higher dose?” As teratogen information specialists, we receive many inquiries regarding folic acid; and it was understandable why this healthcare provider was confused as the guidance isn’t exactly straightforward.

What is folic acid?

Folic acid is the lab made form of folate. Folate is a B9 vitamin. Folate and folic acid help the body create new cells and can lower the chance of having a child with a class of birth defects called neural tube defects, which are problems with the brain and spinal cord. The neural tube forms very early in pregnancy (around 4 to 6 weeks after the first day of the last menstrual period), so it’s important that any woman who could become pregnant get enough folic acid at least one month BEFORE she gets pregnant. In the United States many of our foods, such as breakfast cereal, bread, pasta, and rice are fortified with folic acid, which meant the vitamin has been added to the food. According to the Centers for Disease Control and Prevention (CDC), folic acid fortification programs have led to a 35% decrease in the rate of neural tube defects! We also get folate, which is the naturally occurring form of Vitamin B9, from foods like dark leafy greens, beans, citrus fruits, and nuts. However, only about 50% of this form is bioavailable (able to be absorbed and used by the body) so additional intake, in the form of a supplement, is recommended by organizations like the CDC and National Institutes of Health (NIH).

How much is needed?

The CDC recommends that all women of reproductive age get at least 400 mcg (0.4 mg) of folic acid each day. Once pregnant, organizations like The NIH and the United States Preventative Services Task Force (USPSTF) recommend that women who are pregnant get 600 to 800 mcg (0.6 to 0.8 mg) of folic acid per day. This amount can usually be met by taking an over-the-counter prenatal vitamin; a higher amount is not recommended for most pregnant women.

Women who have previously had a pregnancy affected by a neural tube defect (NTD) should take a higher dose of folic acid if they are planning to become pregnant again. The CDC and the American College of Obstetricians and Gynecologists (ACOG) recommends 4,000 mcg (4 mg) per day for these individuals. This higher dose should be started at least one month before becoming pregnant and should be continued through the first three months of pregnancy.

So what about Dr. Rodriguez’s patient who was on an anti-epileptic drug (AED) for her seizure disorder? Many, but not all, medications in the AED class are known as “folic acid antagonists.” This means that they can interfere with how the body absorbs and uses this important vitamin. If someone becomes pregnant while taking a folic acid antagonist, they may have lower levels of folic acid in their body and their pregnancy could be at higher risk of neural tube defects. That said, there is no great research that shows that taking extra folic acid would lower the risk of NTDs for women taking folic acid antagonists. So, should a woman taking an AED stick with the 400 mcg per day that is already recommended for everyone, or take more just in case it could be helpful?

Let’s look at the current professional recommendations:

• The American Academy of Neurology and the American Epilepsy Society guidelines state that all women of childbearing age, with or without epilepsy, should be supplemented with at least 400 mcg (0.4 mg) of folic acid per day prior to conception and during pregnancy. They go on to say there is not enough data to know if taking folic acid at doses higher than 400 mcg offer greater protective benefits for women on AEDs.

• The American College of Obstetricians and Gynecologists (ACOG) recommends 4000 mcg (4 mg) of folic acid per day for individuals at increased risk of having a baby with a NTD, which includes women with seizure disorders.

• The Centers for Disease Control and Prevention (CDC) only recommends a higher dose of folic acid for those with a history of a pregnancy affected by a NTD.

• The U.S. Department of Health and Human Services (Office of Women’s Health) recommends talking to your doctor to determine the right dose of folic acid if you are taking a medication for epilepsy.

Clear as mud, right? The current consensus seems to be that there is no consensus. Some groups recommend a higher dose while others do not. In situations like this where there is no clear consensus from the professional groups, it comes down to weighing the risks vs. benefits. The risks include the fact that higher doses of folic acid are not well studied in pregnancy, could mask a B-12 deficiency, and may actually make some medications less effective. The benefits of taking more are theoretical (not proven). A higher dose of folic acid might be protective in preventing birth defects while on a folic acid antagonist, but there is not enough research to know if this is true. Ultimately, much more data will be needed to come up with clear guidelines for women with epilepsy.

Because Dr. Rodriguez’s patient was on carbamazepine, a folic acid antagonist that is associated with a higher chance for neural tube defects, she decided that she would have a thorough discussion of the risk vs. benefits of taking a higher dose of folic acid with her patient before she became pregnant. Dr. Rodriguez was glad she hadn’t missed any overarching recommendations for women who need to take medication to control their seizure disorders during pregnancy. She ended her chat by saying: “It can be a challenge to keep up to date with all the recommendations. I’m so glad to have access to MotherToBaby to be able to ask questions like this.”

MotherToBaby specialists are always happy to review the latest data and professional recommendations with healthcare providers and patients alike. If you have questions about folic acid, epilepsy medication, or any other exposures in pregnancy or lactation, please feel free to get in touch.

‘Best for You. Best for Baby.’ Focus of National Birth Defects Prevention Month 2019

FOR IMMEDIATE RELEASE
January 8, 2019

BRENTWOOD, TN – “A baby is born with a birth defect in the United States every 4 ½ minutes. We can change that alarming statistic,” said Christina Chambers, PhD, MPH, President of MotherToBaby, a free service of the non-profit Organization of Teratology Information Specialists (OTIS). MotherToBaby is joining with leading prenatal health experts from the National Birth Defects Prevention Network (NBDPN), Centers for Disease Control and Prevention (CDC), American Academy of Pediatrics, the March of Dimes, and the Teratology Society this month to increase awareness of 5 critical tips to reduce the chances of having a baby with a birth defect.

The National Birth Defects Prevention Month campaign theme, “Best for You. Best for Baby.” aims to raise awareness of preventable birth defects. “Furthermore, we want to emphasize the importance of pregnancy registries, which often lead to the discovery of even more ways to prevent birth defects,” explained Dr. Chambers, who also serves as professor of pediatrics at UC San Diego. MotherToBaby will join the Teratology Society and the Society for Maternal-Fetal Medicine in co-hosting a free two-part webinar series for healthcare providers on the importance of pregnancy exposure research, its challenges and the new Task Force on Research Specific to Pregnant and Lactating Women (PRGLAC) report. The webinar series will take place Thursday January 17th at 1pm-1:30 ET and Tuesday January 29th at 12pm-12:30p ET and will be free to join, but advanced registration is required at the following links:

• Current and Future Trends in Research with Pregnant and Lactating Women (Part 1): http://bit.ly/PregResearch1
• Using Registries and Crowdsourcing to Conduct Research with Pregnant and Lactating Women (Part 2):
  http://bit.ly/PregResearch2

MotherToBaby provides free evidence-based information to mothers, health care professionals, and the general public about medications and other exposures during pregnancy and while breastfeeding through its helpline (866) 626-6847, texting service (855) 999-3525, or via live chat and email on www.MotherToBaby.org. MotherToBaby also has a free app available for iOS and Android devices. MotherToBaby is recommended by many agencies, including the CDC.

MotherToBaby encourages the public to follow these steps to increase chances of a having a healthy baby:

1. Be sure to take 400 micrograms (mcg) of folic acid every day.
   • Folic acid is very important because it can help prevent some major birth defects of the baby’s brain and spine.
2. Book a visit with your healthcare provider before stopping or starting any medicine.
   • There are often benefits to continuing treatment throughout pregnancy. Discussing a treatment plan before a pregnancy allows a woman and her health care provider to weigh the pros and cons of all options to keep mom and baby as healthy as possible.
3. Become up-to-date with all vaccines, including the flu shot.
   • Having the right vaccinations, like the flu and Tdap vaccines, at the right time during pregnancy can help keep a woman and her baby healthy.
4. Before you get pregnant, try to reach a healthy weight.
   • Obesity increases the risk for several serious birth defects and other pregnancy complications.
5. Boost your health by avoiding harmful substances during pregnancy, such as alcohol, tobacco, and other drugs.
   • There is no known safe amount of alcohol during pregnancy and its exposure can cause major birth defects.
   • Smoking during pregnancy can cause dangerous chemicals to damage the placenta and/or reach baby’s bloodstream.
   • The opioid addiction epidemic has led to a sharp increase in Neonatal Abstinence Syndrome (NAS), premature birth and drug withdrawal in developing babies.

“Birth defects are a common cause of death in the first year of a baby’s life, but change happens through awareness,” added Jason L. Salemi, PhD, MPH, NBDPN President. “We’re thrilled MotherToBaby is doing its part to positively change the outcome for babies across North America.”

How You Can Help

MotherToBaby encourages health advocates as well as the general public to be active participants in National Birth Defects Prevention Month. Follow and share #Best4YouBest4Baby messages on social media platforms, such as Facebook, Twitter, Instagram and LinkedIn. In addition, the complete 2019 NBDPN Birth Defects Prevention Month information packet, including this year’s primary tips for birth defects prevention, “Best for You. Best for Baby. 5 Tips for Preventing Birth Defects,” is available online at: https://www.nbdpn.org/bdpm.php. All materials can be printed, electronically conveyed, or added to websites for distribution as needed.

Additional Resources to Support Healthy Pregnancies

Centers for Disease Control and Prevention
The CDC’s National Center on Birth Defects and Developmental Disabilities (NCBDDD) strives to advance the health and well-being of our nation’s most vulnerable populations.
www.CDC.gov/ncbddd

American Academy of Pediatrics
Dedicated to the health of all children, providing age-specific health information.
www.healthychildren.org

The Teratology Society
An international and multidisciplinary group of scientists including researchers, clinicians, epidemiologists, and public health professionals from academia, government and industry who study birth defects, reproduction, and disorders of developmental origin.
www.Teratology.org

March of Dimes
An organization aiming to make sure babies get the strongest start possible as well as reducing the rate of prematurity.
www.marchofdimes.org

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Media Contact: Nicole Chavez, 619-368-3259, nchavez@MotherToBaby.org. Interviews in Spanish are also available.

ATLANTA, GA– A new free service, providing expert answers about medications and other exposures during pregnancy and breastfeeding, is giving expectant moms in Georgia another reason to be thankful this Thanksgiving.

Emory University School of Medicine announces MotherToBaby Georgia, a free statewide counseling service that connects experts in the field of birth defects research with expectant moms, health care providers, and the general public. All it takes is a simple phone call to a toll-free number, 866-626-6847. MotherToBaby GA is funded by the Georgia Department of Behavioral Health and Developmental Disabilities.

MotherToBaby GA is an affiliate of the international non-profit Organization of Teratology Information Specialists (OTIS), a prestigious professional society that supports and contributes to worldwide initiatives for education and birth defects research. MotherToBaby affiliates and OTIS are suggested resources by many agencies, including the Centers for Disease Control and Prevention (CDC), dedicated to providing evidence-based information.

“Reliable information about the risks of medications, vaccines, alcohol, drugs of abuse, chemicals, and other exposures during pregnancy or while breastfeeding, is often difficult to find, especially online. We wanted to be sure that pregnant women and health care providers knew that experts on the most cutting edge research were readily available to them,” explained Claire Coles, PhD, director of MotherToBaby GA, which is housed at the Center forMaternal Substance Abuse and Child Development Center in the Department of Psychiatry and Behavioral Sciences at the Emory School of Medicine.

Dr. Coles further explains the need for this sort of counseling since approximately 50% of women report taking at least one medication during pregnancy.  “The average woman doesn’t find out she’s pregnant until she’s five or six weeks along.  That means a woman could have been consuming alcohol or taking medications during that time without knowing she’s pregnant. She then finds herself deeply concerned about what it might mean for her developing baby.”

Surveys indicate that while the majority of callers are pregnant women, most have been referred by physicians, nurses, midwives and pharmacists.

“What is passed from mother to baby is exactly what we educate the public about, which is why we strongly believe MotherToBaby GA will provide a beneficial service in our state,” said Patricia Olney, MS, board certified genetic counselor and pregnancy risk information specialist. Olney answers calls from around the state and provides counseling over the phone. “We offer an added layer of support by providing her with an individualized risk assessment so she may make informed health decisions along with her primary health care provider,” she added.

For more information about MotherToBaby GA please visit: www.MotherToBaby.org or www.emory.edu/msacd.

For counseling, call toll-FREE 866-626-6847 from throughout North America. In Georgia, you can also call  855-789-6222, or email: mothertobaby@emory.edu.

Media Contact: Patricia Olney, MS, CGC at 855-789-6222 or mothertobaby@emory.edu.

Researchers from the UC San Diego School of Medicine and Boston University, in collaboration with the American Academy of Allergy Asthma and Immunology (AAAAI), have found evidence of the H1N1 influenza vaccine’s safety during pregnancy. The national study, which was launched shortly after the H1N1 influenza outbreak of 2009, is summarized in two companion papers published online on September 19 in the journal, Vaccine.

“The overall results of the study were quite reassuring about the safety of the flu vaccine formulations that contained the pandemic H1N1 strain,” said Christina Chambers, PhD, MPH, Director of the non-profit Organization of Teratology Information Specialists (OTIS) Research Center and lead investigator of UC San Diego’s team. “We believe our study’s results can help women and their doctors become better informed about the benefits and risks of flu vaccination during pregnancy.”

Despite federal health authorities’ recommendations that all pregnant women be vaccinated for influenza, it is estimated that less than 50 percent of women follow this advice, largely because they are concerned about the effects flu vaccines might have on the developing baby.

Since it was anticipated that the 2009 H1N1 influenza season would be severe, a national study was launched by the Vaccines and Medications in Pregnancy Surveillance System (VAMPSS), a collaboration between UC San Diego School of Medicine and Boston University and coordinated by AAAAI to gather data on the safety of this vaccine during pregnancy.

The team from UC San Diego followed 1,032 pregnant women across the United States and Canada who either chose to receive an influenza vaccine or were not vaccinated during one of the three seasons from 2009-2012. Women were recruited through MotherToBaby, a service of OTIS.

Chamber’s team found that women vaccinated during pregnancy were no more likely to experience miscarriage, have a baby born with a birth defect or have a baby born smaller than normal compared with those who did not receive a vaccination. Although vaccinated women were more likely to have their babies before term, on average these infants were delivered three days earlier than those born to unvaccinated women.

“We found no meaningful evidence of an increase in risk for many specific major birth defects if a woman received the flu shot early in pregnancy,” said Carol Louik, ScD, lead investigator of the Boston University team. “A concern about the risk of specific birth defects was a critical question that has not been considered very much until now, and our data are reassuring.”

The studies were funded by the U.S. Department of Health and Human Services Biomedical Advanced Research and Development Authority.

Additional contributors to the paper authored by UC San Diego included Diana Johnson, Ronghui Xu, Yunjun Luo, Allen A. Mitchell, Michael Schatz, Kenneth L. Jones and the OTIS Collaborative Research Group.

The VAMPSS system was established in 2010 under the umbrella of AAAAI, a professional practice group with a strong interest in prenatal exposures that might affect their asthma, allergy and immunology patients. VAMPSS fills a critical gap in evaluating the safety of vaccines and medications in pregnancy since most cannot be tested in pregnant women using clinical trials. To learn more about VAMPSS, please visit PregnancyStudies.org.

“Risks and Safety of Pandemic H1N1 Influenza Vaccine in Pregnancy: Birth Defects, Spontaneous Abortion, Preterm Delivery, and Small for Gestational Age Infants”.
Doi: 10.1016/j.vaccine.2013.08.097 (pp. 5058-5064).

“Risks and Safety of Pandemic H1N1 Influenza Vaccine in Pregnancy: Exposure Prevalence, Preterm Delivery, and Specific Birth Defects”.
Doi: 10.1016/j.vaccine.2013.08.096 (pp. 5065-5072).