Lately, I have been asked numerous times for my opinion on COVID-19 vaccines for pregnant women. While I try not to give my opinion, I base recommendations on currently available evidence. I recommend anyone pregnant or looking to become pregnant discuss the vaccine with their obstetrician. But it is essential to come to the discussion with some background knowledge. So, let’s talk about it…
The Centers for Disease Control and Prevention (CDC), the Society for Maternal-Fetal Medicine (SMFM), and the American College of Obstetricians and Gynecology (ACOG) all have published position statements recommending COVID-19 vaccinations for pregnant women. Unfortunately, despite these recommendations, less than 40% of pregnant women in the United States have been vaccinated against COVID-19, with only 19% of women getting vaccinated while pregnant (CDC, 2021).
So, what safety data do we have?
As of December 2021, over 177,000 vaccinated pregnant women have enrolled in the CDC’s V-safe post-vaccination health checker. V-safe is very different than the Vaccine Adverse Event Reporting System (VAERS). In VAERS, anybody can post what they think is an adverse event to a vaccine. In a previous post, we discussed why this data is notoriously inaccurate and should NOT be used as a sole indicator of vaccine adverse events due to many confounders.
V-safe is a smartphone-based tool that uses text messaging and web surveys to give personalized health check-ins after receiving a COVID-19 vaccine. Through v-safe, you can quickly tell CDC if you have any side effects after getting a COVID-19 vaccine. Suppose you enroll in V-safe and report that you were pregnant at the time of vaccination or after vaccination. In that case, the CDC COVID-19 pregnancy registry staff will contact you several times throughout your pregnancy for health check-ins.
No unexpected pregnancy or fetal problems have been identified from the over 177,000 vaccinated pregnant women registered with V-safe. Specifically, there have been no reports of any increased risk of pregnancy loss, growth problems, or congenital disabilities. Don’t take this as a statement that bad things can’t happen. They do, just not at a rate higher than expected compared to unvaccinated pregnant women. These findings align with what has been seen in several earlier studies on COVID-19 vaccine safety in pregnancy (Shimabukuro, 2021; Kharbanda, 2021).
The most recent study assessing the risks of the vaccine in pregnancy was just published by the CDC yesterday (Lipkind, 2022). They looked at over 46,000 pregnant women and included those who received the initial vaccine series and those who received boosters compared to those who did not receive the vaccine. Overall, 6.6 percent of babies were born prematurely, before 37 weeks of pregnancy, and 8.2 percent were born small for their gestational age, weighing less than 5 pounds and 8 ounces. These numbers were essentially the same compared to pregnant women who did not receive the vaccine.
What data is missing?
The first trimester is when fetal organ development occurs and is often the most at-risk time for the development of congenital disabilities. The most significant limitation in the Lipkind study is that only 1.7% of all vaccinations happened during the first trimester. So, this report really can’t conclude the risk to vaccinated women in the first trimester.
However, we have data suggesting this is unlikely to be an issue. When a new drug or vaccine is being developed, researchers must complete Developmental and Reproductive Toxicity studies (also known as DART studies). DART studies assess effects on male and female fertility, developmental toxicity, and pre/postnatal development.
DART studies have been done for both mRNA vaccines before they were approved. According to the report presented to the European Medicines Agency, animal studies using the Pfizer/BioNTech COVID-19 vaccine do not indicate direct or indirect harmful effects concerning pregnancy, embryo/fetal development, parturition, or postnatal development (EMA).
A DART study of Moderna’s vaccine was done in rats and was reviewed by the FDA. This study concluded that the Moderna vaccine given before mating and during gestation periods did not affect female reproduction, fetal/embryonal development, or postnatal developmental (FDA).
In a DART study of the J&J/Janssen COVID-19 vaccine, female rabbits were administered the vaccine seven days before mating and repeated early in gestation and again late in pregnancy. Furthermore, no vaccine-related adverse effects on female fertility, embryo-fetal, or postnatal development were observed up to postnatal day 28 (FDA 2021).
What is the risks versus the benefits?
It is essential to understand that the overall risk of poor outcomes from COVID-19 in women of childbearing age is still low, but pregnancy significantly increases this risk. As of January 2nd, 2022, there have been 155,587 cases of COVID-19 in pregnant women reported to the CDC (CDC, 2022). Of these cases, the overall risk of hospitalization for COVID-19 was 16.8%, with an overall risk of death at 0.16%. The highest risk was seen in the 25 to 29-year-old age group. When comparing this risk to non-pregnant women, the rate of hospitalization for COVID-19 is over 3 X more likely in pregnant women (Zerbo, 2021).
The risk of adverse effects is higher for every possible outcome from pregnant women who get COVID-19 than in pregnancies with no COVID-19. The July CDC report has a lovely table that breaks it down (see Table 2 in the report). They looked at about 500 thousand deliveries (6,650 of which had COVID-19). 97% of pregnant people hospitalized, either for illness or labor and delivery, with confirmed SARS-CoV-2 infection were unvaccinated. Further, this study shows that pregnant women with COVID-19 have a 2.7 X increased risk of clotting issues, a 35 X increased risk of acute respiratory distress syndrome, a 3.5 X increased risk of renal failure, a 2.2 X increased risk of adverse cardiac event, a 1.2 X increased risk of preterm labor, and a 1.2 X increased risk of stillbirth. In this study, 0.7% of pregnant women hospitalized with COVID-19 died. In contrast, none of the non-pregnant women hospitalized with COVID-19 died, suggesting a 17 X increased risk of death in COVID-19 if you are pregnant. (Ko, 2021).
In studies comparing the risk of hospitalized COVID-19 in women who are pregnant vs. not pregnant, women who are pregnant are 3 X more likely to need ICU care, 2-3 X more likely to require intubation (Panagiotakopoulos, 2020; Zambrano, 2020; Delahoy, 2020)
1.2 X increased risk of preterm labor and stillbirth
3 X increased risk of ICU admission
2-3 X increased risk of needing intubation
17 X increased risk of death
But what about blood clots?
With the Johnson & Johnson vaccine, the CDC reported cases of thrombosis with thrombocytopenia syndrome (TTS) at a rate of about seven cases per 1 million vaccinated women between 18 and 49 years old (0.0007% rate). Of note, the background rate of TTS before COVID-19 even existed was 2-5 cases per million (0.0005% rate). Again, TTS is much more likely to occur with COVID-19 infection at a rate of 39 cases per million (Furie, 2021). It is essential to understand that the excess rate of TTS has ONLY been observed in the Johnson & Johnson vaccine in the U.S. and not with either mRNA vaccine.
Venous thromboembolism (vein blood clots) occurs in women who have not received any COVID-19 vaccine at a rate of 5 cases per 10,000 women. This risk increases to 10 cases per 10,000 women who use estrogen-containing oral birth control. The risk further increases to 8-20 cases per 10,000 women who become pregnant. Again, this is nowhere near the chance of blood clots from COVID-19 infection at a rate of 30 cases per 10,000 pregnant women. Studies assessing the rate of developing any blood clots from either mRNA vaccine have not shown an increased rate of blood clots beyond the expected background rate for women of childbearing age (5 cases per 10,000).
A summary table of the chance of developing blood clots specific to women of childbearing age is outlined below.
Can't the vaccine make me infertile?
There has been a misguided rumor that the COVID-19 vaccine can lead to fertility issues. This misconception arose when a false report surfaced on social media saying that the spike protein on this coronavirus was the same as another spike protein called syncytin-1, which is involved in the growth and attachment of the placenta during pregnancy. The false report said that getting the COVID-19 vaccine would cause a woman’s body to fight this different spike protein and affect her fertility. The two spike proteins are entirely different, and getting the COVID-19 vaccine has not been shown to affect fertility. This was shown in the various DART studies we already discussed. Another study from September of 2021 showed no decrease in success of in vitro fertilization in women who had a COVID-19 vaccine or from SARS-CoV-2 infection (Morris, 2021). During the Pfizer vaccine tests, 23 women volunteers involved in the study became pregnant. Only one person in the trial suffered a pregnancy loss. This person received the placebo and not the actual vaccine.
Something else to consider...
While the purpose of this article is to focus on COVID-19 vaccination data in pregnancy, some generalizable data can help us. Many anecdotal reports of people claiming they see higher rates of strokes and heart disease from the COVID-19 vaccines. This just isn’t supported by the current data. An August 2021 study of 30 MILLION people in Europe showed a slight but statistically insignificant increase in thrombotic events, but nowhere near the rate seen to consider the vaccine a cause of these events and nowhere near the rates seen when someone gets hospitalized for COVID-19 (Hippisley-Cox, 2021). The infographic from this report summarizes the study data nicely.
But I can still get COVID-19 even if I had the vaccine. So what's the point?
It is important to consider the protection offered by the vaccine. An ongoing analysis of outcomes in patients with COVID-19 based on vaccination status is being conducted by the Kings County public health department. Over the last 30 days, their data shows that patients who are not fully vaccinated are 6 X more likely to develop a symptomatic infection, 33 X more likely to be hospitalized, and 45 X more likely to die of COVID-19 related illness.
In conclusion, the evidence regarding vaccine safety in pregnancy favors getting vaccinated to decrease the risk of adverse outcomes. While no intervention is without risk, the risk of not doing anything appears less favorable. People considering vaccination should always discuss this with their doctor as personal aspects of health may play a factor in a risk-benefit discussion.
- Monoclonal Antibodies for COVID-19 – An evidence based update - January 18, 2022
- COVID-19 Vaccines in Pregnancy - January 6, 2022
- COVID-19 Boosters….are they necessary? - October 8, 2021