As the Centers for Disease Control and Prevention (CDC) point out, vaccines against SARS-CoV-2 protect against severe illness and death.
Recently, scientists set out to compare post-vaccine experiences among pregnant and lactating people and people who are neither. The study draws data from a survey of over 17,000 individuals who received a COVID-19 vaccine.
The researchers have published their initial findings in a research letter in JAMA Network Open. They concluded that “COVID-19 vaccines were well-tolerated among individuals who were pregnant, lactating, or planning pregnancy.”
Lead researcher Dr. Alisa Kachikis, an obstetrician-gynecologist at UW Medicine, in Seattle, described the study, which began in January 2021, to Medical News Today.
“We started the University of Washington COVID-19 [Vaccine] in Pregnancy and Lactation Registry when the COVID-19 vaccines were initially rolled out without any data on the vaccine in the pregnant and lactating populations,” she said.
“Our prospective, survey-based study then started to capture information on the experience of pregnant and lactating individuals, as well as people who were neither pregnant nor lactating but planning pregnancy.”
The study collected data from 17,525 individuals in the United States. The participants were adults who were either pregnant, lactating, or planning pregnancy at the time of COVID-19 vaccination.
The researchers recruited and enrolled participants online through the university’s COVID-19 Vaccine in Pregnancy and Lactation Registry.
The researchers asked the participants to provide data about their demography, pregnancy status, and vaccination perception, as well as outcome data — including reports of vaccine reactions. The initial findings are based on an analysis of data collected from January through March 2021.
To analyze the effects of the COVID-19 vaccine, the team divided the participants into three groups: 7,809 participants were pregnant, 6,815 were lactating, and 2,901 were neither pregnant nor lactating but planning for pregnancy. These groups represented 44.6%, 38.7%, and 16.5% of the study population, respectively. The scientists assigned participants to one of the three groups at the time of their first vaccine dose.
The results showed that about 17,005 (97%) participants reported reactions after their first dose. The most common reactions were pain at the injection site and fatigue.
There were also reports of increased reactions to the second dose, compared with the first dose. But the reactions were similar across all groups.
When the researchers analyzed their data, 6,586 of the participants in the pregnancy group had received a second dose of the vaccine. Among these participants, 6,244 (94.8%) were still pregnant, 288 (4.3%) had given birth, and 49 (0.7%) reported pregnancy loss at the time of their second COVID-19 vaccine dose.
Meanwhile, 155 (2.3%) lactating participants reported interrupted breastfeeding after the first dose and 130 (2.2%) reported this after the second dose.
There were also reports of a noticeable decrease in milk supply for less than 24 hours following the vaccine administration. This was observed in 339 (5.0%) participants after the first dose and 434 (7.2%) after the second dose.
The researchers conclude that the benefits of the COVID-19 vaccine outweigh the risks for pregnant and lactating people.
This conclusion is shared by Olajumoke Adebayo, a maternal health expert and young midwife leader at the International Confederation of Midwives. Adebayo explained, “There was a lot of uncertainty about the effect of vaccines on pregnant and lactating women, so this [research] is a good starting point.”
Dr. Amy Roskin, the chief medical officer of the birth control delivery company The Pill Club, also affirmed the findings:
“I’m really glad that this study provides additional support to the recommendations from major medical organizations, like the American College of Obstetrics and Gynecology, that support vaccination for individuals who are planning pregnancy, pregnant, or lactating.”
However, this study is not without limitations. The researchers acknowledge that it may contain some bias. This is because participants were drawn from a convenient sample size, mostly self-reported their reactions, and largely consisted of healthcare workers — all due to vaccine eligibility when the study was being conducted.
The researchers told MNT that the investigation is ongoing and interested individuals are welcomed to participate.