Covid-19: vaccination does not increase risk of miscarriage, new study finds

A new study has found no evidence of an increased risk of early miscarriage after vaccination against Covid-19, regardless of the vaccine received. A conclusion that adds to those of other reports supporting vaccination against Covid-19 during pregnancy.

Should we do vaccinate against COVID-19 when you are expecting a child? According to discussions on forums and social networks, many expectant mothers are wondering about the possible repercussions on the course of their pregnancy and on the health of the child. New study published by University of Ottawa researchers in the New England Journal of Medicine examines this important question and confirms findings from previous work on vaccine safety during pregnancy. Note that there is no correlation between vaccination against COVID-19 and the risk of miscarriage in the first trimester.

The team of scientists analyzed several national medical registers in Norway to compare the proportion of women vaccinated having had a miscarriage in the first trimester and women who were still pregnant at the end of the first trimester. “We have not seen any increased risk of early miscarriage after vaccination against COVID-19, which is in line with other reports that have triggered the administration of such a vaccine. during pregnancy. ”, Write the authors of the study. “These results are reassuring for women vaccinated at the start of pregnancy and add to the numerous data that have declared the safety of vaccines against COVID-19 during pregnancy. »

Note that the researchers found no link between the type of vaccine received and miscarriages : Vaccines used in Norway include those from Pfizer-BioNTech, Moderna and AstraZeneca. “It is important that pregnant women are vaccinated, because they continue to be hospitalized and in pain. complications from COVID-19, not to mention that their baby is at risk of being born too early. In addition, the vaccination is likely to protect him against COVID-19 in the months after birth. », They conclude. In France, this observation is shared by Inserm, which indicated last June that infected pregnant women by Covid-19 are more likely to develop complications, and that these risks can have repercussions on the health of the child.

The organization also pointed out that according to preliminary data analyzed by the American Centers for Disease Control and Prevention (CDC) on pregnant women vaccinated with an mRNA vaccine between December 2020 and February 2021, the most common side effects after the injection (headaches, fatigue, muscle pain, etc.) are similar to those encountered by women who are not pregnant. To consolidate data on pregnant women, the ANSM * called on volunteers, pregnant and vaccinated to carry out a cohort study. All women of full age and pregnant at the time of vaccination, regardless of the stage of their pregnancy, can participate in the study.

Covid-19: Should pregnant women be vaccinated?

Should we recommend vaccination against Covid-19 to pregnant women? Are they all affected by the current vaccination campaign? Is pregnancy a risk factor? Is the vaccine safe for the fetus? In a press release, the National Academy of Medicine delivers its recommendations. We take stock.

Messenger RNA COVID 19 vaccines: they don’t get into breast milk

Is it possible that the messenger RNA technology present in the Pfizer and Moderna vaccines could be transmitted to the infant through breast milk? This situation is really not likely according to researchers, study in support.

Women who are breastfeeding and wondering if COVID-19 vaccination is safe for their babies can be reassured by the results of a new scientific study. Researchers at the University of California at San Francisco report that “vaccine-associated mRNA”, the active components of Moderna and Pfizer / BioNTech vaccines, “Was not detected in 13 milk samples taken 4 to 48 hours after vaccination from seven breastfeeding people”. Although a larger-scale trial is needed to fully confirm the results, they say their findings “provide important evidence to strengthen current recommendations that vaccine-bound mRNA is not transferred to the infant. »

These results suggest that pregnant women will therefore not have to choose between vaccination against COVID-19 and breastfeeding. They are all the more important because, as scientists remind us, they answer an important safety question knowing that breastfeeding women have not been included as a precautionary principle in clinical trials. COVID-19 vaccines. The study consisted of performing a detailed, high-tech analysis of the breast milk of seven breastfeeding mothers with an average age of around 38 years, each who received two doses of the Pfizer / BioNTech (Comirnaty) or Moderna (COVID-19 Vaccine) vaccine. Moderna). The samples breast milk were subsequently tested up to 48 hours after the initial collection.

The results showed that no trace of mRNA from the vaccines was not found in any sample. Even so, if minute amounts of mRNA, far too small to be detected by their tests, did manage to pass into breast milk, “this genetic material would be degraded by the infant’s gastrointestinal system anyway. “, Say the scientists. The latter also wish to recall that the World Health Organization and the Academy of Breastfeeding Medicine support the safety of maternal immunization. during breastfeeding, like the American College of Obstetrics and Gynecology and the American Academy of Pediatrics. In France, this is also the case with the Haute Autorité de Santé, in a note published in March 2021.

The organization made it known that “there is no study on the passage of these vaccines in milk or in lactating women. He also recalled that, on the basis of biological mechanisms (rapid degradation of mRNAs), there is no expected effect in children breastfed by a vaccinated woman: vaccination in breastfeeding women is therefore possible. “Many other vaccines have been administered to nursing mothers in the past, and there is no example where they have been shown to be harmful. », Concludes the scientific team, whose study was published in JAMA Pediatrics. More generally, the Academy of Medicine recommends preserving breastfeeding by vaccinated women during pregnancy, antibodies transmitted by milk having a protective effect on the newborn.

COVID-19: mRNA vaccination during pregnancy is safe, study finds

Researchers have studied the impact of mRNA vaccination (Pfizer / BioNTech and Moderna) in pregnant women. Such vaccination is authorized in the United States, which allowed scientists from an official health agency to publish a large study in this area. The first results are encouraging.

More than a year after the start of the Covid-19 pandemic, knowledge of this infection in pregnant women are still fragmentary. Except that studies have shown that the transmission of SARS-CoV-2 appears rare through the intrauterine route and via breast milk. In addition, after birth, mother-to-child transmission would remain unlikely, subject to proper application of barrier measures. But one question remains: can pregnant women get vaccinated with mRNA vaccines? In France, the Academy of Medicine voted for in March as well as the General Directorate of Health in a note of April 03 (from the second trimester, with or without comorbidity, then on July 20, from the first trimester) .

The United States has just published in the New England Journal of Medicine the largest scientific study ever conducted in this field, and its conclusions are intended to be reassuring. Conducted by researchers from the Centers for Disease Control and Prevention, it was based on data from more than 35 women who received the two injections of Moderna or Pfizer / BioNTech vaccines (Corminaty) during their pregnancy. Their work did not include the single-dose vaccine de Johnson & Johnson, made available only after the study, and what is more is uncertain as the US authorities investigate the occurrence of serious cases of blood clots in several people.

What is the benefit of getting vaccinated during pregnancy?

In the case of these two vaccines, it is a question of causing the fragments of infectious agents to be produced directly by the cells of the vaccinated individual. For this, it is not the virus in its attenuated form that is injected but DNA or RNA molecules encoding for proteins of the pathogen. The cells of the vaccinated person located at the injection site are then able to manufacture said proteins themselves, chosen upstream for their ability to trigger a significant immune response. This is the Spike protein present on the surface of SARS-CoV-2, the “key” to attaching itself to, entering and infecting cells.

The authors of the study specify that although pregnant women were excluded from the studies that led and allowed the emergency authorization of vaccines, the data did not show no harm in women who were pregnant without knowing it at the time of enrollment in clinical trials. The latter also recall that “pregnant women infected with the coronavirus are exposed to high risks of complications, in particular hospitalization in intensive care, premature births and death. The follow-up of these 35 patients spread from mid-December 000 to the end of February 2020, via a vaccine monitoring system based on the use of a smartphone.

No serious adverse event has been reported

The study also included reports of pregnancy complications from 827 women on a U.S. vaccine safety registry. Of the completed pregnancies, 86% of them resulted in births, mainly to women vaccinated in the third trimester. In addition, about 13% of pregnant women reported miscarriages, less than 1% stillbirths, 9% premature births and 2% birth defects. “These rates are all in the same range observed in the reports in pregnant women before the pandemic. », Specifies the scientific team in a press release.

Most of the women in the surveillance group reported pain at the injection site but more serious reactions (headache, fevers, muscle pain, chills) were less frequent. “They seemed more prone to injection site pain with both vaccines, but less likely to experience other reactions than non-pregnant women,” the researchers note. “The results did not show obvious safety signals in pregnant women. who received mRNA vaccines. However, monitoring of a large number of women vaccinated earlier in pregnancy is necessary in order to better understand the outcomes for pregnancy, mother and infant. », They conclude.

Anti-Covid vaccine in pregnant women: a study gives very encouraging results

A new study on the Covid-19 vaccine administered during pregnancy shows very encouraging results. Pregnant women who were vaccinated developed a robust immune response and their antibodies were passed on to the baby. We tell you everything.

In what they qualify as the largest study of its kind, American researchers report having observed very high efficacy of new mRNA vaccines against Sars-CoV-2 (anti-Covid Pfizer and Moderna vaccines) in pregnant women or breastfeeding.

The study, published on March 25, 2021 in L’ “American Journal of Obstetrics and Gynecology”, Focused on 131 women of childbearing age, broken down as follows: 84 pregnant women, 31 nursing mothers, and 16 women who are neither pregnant nor breastfeeding.

All received one of two new messenger RNA vaccines : either the one designed by the laboratories Pfizer / BioNTech, or that of biotech Modern.

Results: the participants had equivalent levels of antibodies following the injection of the vaccine, proof of its effectiveness whatever the biological state of the woman of childbearing age. Post-injection side effects were rare, and comparable among all study participants.

« This news of the vaccine’s excellent efficacy is very encouraging for pregnant and breastfeeding women, who were excluded from initial trials of the Covid-19 vaccine. Said Dr. Andrea Edlow, specialist in maternal and fetal medicine, and co-author of the study. “ Filling information gaps with real data is essential – especially for our pregnant patients, who are at higher risk for complications from Covid-19. This study also highlights how eager pregnant and breastfeeding women are to participate in research. ”, She underlined in a press release.

Due to the size of the uterus at the end of pregnancy, which reduces respiratory capacity, it is currently considered that pregnant women in the third trimester are at risk for severe form of Covid-19. And hospitalization for this reason can have repercussions on the outcome of pregnancy and childbirth (emergency cesarean section, prematurity, etc.).

Higher antibody levels than after natural infection

The research team reports higher levels of antibodies to the coronavirus during vaccination than if the pregnant participants had been infected with the virus. The antibodies produced as a result of the vaccine were also found in umbilical cord blood samples collected after pregnancy and in breast milk breastfeeding women. Vaccination against Covid-19 would therefore allow pregnant and breastfeeding women to protect yourself from a severe form, But also confer immunity to their fetus and then newborn.

« We now have clear evidence that Covid vaccines can induce immunity that will protect infants “, Assured Galit Alter, co-author of the study. ” We hope this study will enable vaccine developers to recognize the importance [of including] pregnant and lactating women in [clinical] trials. […] Vaccine developers must understand that pregnancy is a special immunological state, where two lives can be saved simultaneously with a powerful vaccine. », Added the researcher.

At the margin, the study also showed higher immune responses after the second injection of Moderna vaccine, compared to those obtained after the second injection of Pfizer’s vaccine.

Vaccination against Covid-19 in pregnant women: where are we?

Expecting a baby in the midst of a Covid-19 pandemic necessarily means asking questions about the risks associated with Covid-19 and transmission to the fetus. Since March 5, 2021, some future mothers, as well as their entourage, can be vaccinated. Is the vaccine safe for the unborn baby? Is pregnancy a risk factor likely to worsen the disease? In a press release dated March 2, 2021, the National Academy of Medicine Communiqué of the National Academy of Medicine, March 2, 2021 ″> delivered its recommendations.

In addition, on March 5, 2021, the government expanded the list of health professionals authorized to administer vaccination against Covid-19. Midwives are now allowed to vaccinate pregnant women.

For its part, the High Authority for Health specifies: “For pregnant women, the HAS recalls that the administration of vaccines against Covid-19 in pregnant women is not contraindicated ; it must be considered whether the potential benefits outweigh the risks to the mother and fetus. In particular, pregnant women over 35 or those with other comorbidities such as obesity, diabetes or cardiovascular diseases, or pregnant women likely to be in contact with infected people due to their professional activity may be offered vaccination. “(” Sars-Cov-2 vaccination strategy, update of risk factors for severe forms of Covid-19 and recommendations on the strategy for prioritizing populations to be vaccinated “)

Pregnant women and those around them authorized to be vaccinated

A decree published on March 5 in the Official Journal specifies that vaccination of pregnant women and those around them is now possible. Midwives are allowed to practice it.

The extension of vaccination to pregnant women or new mothers, as well as their entourage, is therefore recorded. The article published in Official Journal specifies the public concerned: “The midwife can prescribe and perform vaccinations for those around him, as soon as the mother is pregnant and for eight weeks after childbirth […] »

Le Official newspaper also specifies the definition adopted for “the entourage”: “The entourage includes people living in the same home as the child or regularly attending this home, or being responsible for his regular care in this place. »

Covid-19: Should pregnant women be vaccinated?

Press release from the National Academy of Medicine of March 2, 2021

In a press release published on March 2, 2021, the National Academy of Medicine delivers its recommendations for the vaccination of pregnant women.

“A year after the start of the Covid-19 pandemic, knowledge of this infection in pregnant women is still fragmentary. Transmission of SARS-CoV-2 appears rare and harmless intrauterine ; she didn’t not shown in breast milk [1]. After birth, mother-to-child transmission remains unlikely, subject to proper application of barrier measures (mask and hydroalcoholic gel).

Pregnancy: an increased risk of severe form

However, although pregnancy is not yet unanimously considered a factor of seriousness, several data suggest increased risk. A study of Centers for Disease Control and Prevention (CDC) on more than 450.000 women with symptomatic Covid-19 shows that the rate of intensive care unit admission, invasive ventilation, extracorporeal membrane oxygenation and death is higher in pregnant women than in non-pregnant women of childbearing age. In addition, Covid-19 multiplies by 3 the risk of premature childbirth [2]. In addition, factors classically associated with maternal morbidity, such as age over 35, overweight, obesity, hypertension and diabetes, expose women with Covid-19 to more severe forms [3].

No contraindication to vaccinating pregnant women against Covid-19

There is no contraindication to the administration of vaccines during pregnancy, with the exception of live vaccines such as BCG and attenuated viruses (measles, mumps, rubella, chickenpox, yellow fever). On the other hand, certain vaccinations are particularly recommended for pregnant women, especially against influenza and whooping cough [4]. The same arguments can be used for Covid-19: when infection, symptomatic or asymptomatic, occurs during pregnancy, maternal anti-SARS-CoV-2 IgG antibodies are transferred through the placenta; their concentration in cord blood correlates with the concentration of antibodies in the mother and the time between the onset of infection and childbirth. This transplacental passage of specific antibodies of maternal origin induces protection of the newborn against infection by SARS-CoV-2 [5].

The efficacy and safety data in pregnant women are still partial for the three currently authorized vaccines, whether they use messenger RNA (Comirnaty® by Pfizer / BioNTech and COVID-19 Vaccine Moderna®) or a non-viral vector. replicative (COVID-19 Vaccine AstraZeneca®). Although no serious adverse events have been reported so far, these data must be clarified by additional clinical trials. However, animal studies have not revealed harmful effects on pregnancy, fetal and postnatal development, or fertility. That is why WHO authorizes vaccination for pregnant women belonging to a group in which this vaccination is recommended.

Pregnancy and anti-Covid-19 vaccination: recommendations from the Academy of Medicine

In the current context of progressive supply of vaccine doses, aware of the current difficulties of prioritizing the subjects to be vaccinated, the National Academy of Medicine recommends:

to consider pregnancy as a severe risk factor in the event of infection with SARS-CoV-2, and to protect every pregnant woman from any potential source of contamination;
to vaccinate any pregnant woman professionally or family-exposed, or carrying a co-morbidity (age> 35, BMI> 25, hypertension, diabetes);
de do not delay or terminate a pregnancy due to vaccination;
de preserve breastfeeding by women who have been infected with SARS-CoV-2 or vaccinated during their pregnancy, the antibodies transmitted through breast milk having a protective effect on the newborn. “

Press release from the National Academy of Medicine, March 2, 2021

1. Press release from the National Academy of Medicine “Breastfeeding and Covid-19”, September 8, 2020. 2. Rasmussen SA, Jamieson DJ. Pregnancy, postpartum care, and Covid-19 vaccination in 2021. JAMA 2021 Feb 8. 3. Sentilhes L et al. Coronavirus disease 2019 in pregnancy was associated with maternal morbidity and preterm birth. Am J Obstet Gynecol 2020 ; 223 : 914. e1-15. 4. Report from the National Academy of Medicine “Pregnant women must be vaccinated against influenza and pertussis” March 2, 2021. 5. Flannery DD et al. Assessment of Maternal and Neonatal Cord Blood SARS-CoV-2 Antibodies and Placental Transfer Ratios. JAMA Pediatr 2021 : e210038.

Covid-19: vaccination does not increase risk of miscarriage, new study finds

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