Study Shows COVID-19 Vaccines are Safe for Pregnant and Lactating Women

A recent study from researchers at the University of Washington shows that COVID-19 vaccines are well-tolerated among individuals who are pregnant, lactating, or planning pregnancy.

“I think pregnant individuals are hardwired to try to protect their baby, and when there are vaccines and other substances we don’t know about, our reaction is to be wary of them and ask other questions about the vaccine. At this point, with the data we have, it looks like the vaccine is actually really safe,” said a researcher of the study Alisa Kachikis, assistant professor, Maternal-Fetal Medicine, University of Washington. 

In January 2021, Kachikis and a team of researchers began an ongoing survey of women, 44% of whom were pregnant, 38% lactating and 15% who were neither pregnant nor lactating,

The women who participated in the survey provided responses about symptoms experienced after receiving the first dose of a COVID-19 vaccine, in which half reported specifically receiving the Pfizer vaccine.

By March, 17,525 women had responded with 91% of women reporting pain at the injection site, 31% reporting fatigue, and a total mean temperature of 100 degrees Fahrenheit after receiving the shot. 

Only a small group of about 7% of the women reported a decrease in milk supply after receiving the vaccine. 

Kajsa Nelson, a 29-year-old elementary school teacher at Central Kitsap School District in Washington, enrolled in the study the day she received her first vaccine dose in early March, while she was 38 weeks pregnant with her son Otis. 

Nelson was eager to get the first vaccine dose while pregnant, and later get her second dose while nursing, as she had come across studies regarding how different antibodies can protect newborns.

“Otis received a different type of antibody in utero, and because he was receiving it through the placenta, it can protect against circulatory aspects of COVID-19, such as clotting. The second vaccine shot I received, he received antibodies through lactation that can protect against respiratory and lung aspects of COVID-19,” said Nelson. 

Research shows that pregnant or lactating women who receive the COVID-19 vaccine may be able to transfer antibodies to their baby through the placenta or breast milk to provide protection from the virus.

After receiving her first shot, Nelson reported experiencing symptoms of soreness in the arm, and a welt where she had received the shot, lasting a total of five days.

However, when she went for the second shot in early April only weeks after giving birth, she experienced more extreme symptoms.

“About nine hours after the vaccine, I felt horrible chills, indigestion, and intestinal cramps, but it could have been because I was postpartum for six-10 weeks and knew I had multiple layers going on with that second dose,” said Nelson.

Nelson said that within seven hours all symptoms went away, and she felt fine the next day. 

Two weeks later, she awoke to a 100.5-degree fever and a clogged milk duct, causing extreme pain, tenderness, pressure, firmness, and a bright red mark on the skin of her breast. 

“I was given antibiotics, and started working with an international certified breastfeeding consultant,” said Nelson.

Aside from the prescribed antibiotics, Nelson was instructed to try various techniques to heal the clogged duct, including frequently nursing, pumping, using hot water, and dangle nursing, which involves getting on all fours and dangling the breast down to unclog the duct.

Although Nelson said the fever, pain, and other symptoms of the clogged milk duct began to fade with the treatments prescribed within 36 hours of her initial symptoms, the condition continued to interfere with her ability to feed her newborn.

This is because the following month and half she found out that her body was overproducing milk at the site of the clogged milk duct, causing an imbalance of two types of breast milk: foremilk and hindmilk. 

“Foremilk is very sugary, and Otis wasn’t getting the hindmilk which is really fatty, and it affected his nutrition to the point that I had to change the way I was nursing him and go from nursing on both sides to nursing on the other side, a technique called block nursing,” said Nelson. 

Despite the symptoms that Nelson experienced through the second vaccine shot, she said, “It felt really good to know that because I was taking a risk and making a choice that was founded in science, but didn’t have the data yet, that I was a part of that solution, especially with the misinformation that has occurred around fertility and efficacy of the vaccine.”

Nelson has continued to provide survey responses for ongoing research by University of Washington researchers, who now have a total of over 20,000 women enrolled. 

“I think we spent over a year feeling like there is not much we can do with this pandemic, and I really feel like this is the way that pregnant and lactating individuals can help the public and do some good to contribute some data,” said Kachikis.

“We are at a historic time with this novel vaccine, and this could set the stage for vaccines to come in the future and how we roll them out with these specific populations of pregnant or lactating women,” said Kachikis.