Vaccinating pregnant women: there is "robust" evidence that it is safe and avoids serious complications if the pregnant woman contracts covid

The available scientific evidence increasingly supports the vaccination of pregnant women against covid. When Spain began to recommend the injection against the virus to pregnant women, last May, the available information was more limited, although favorable to the injection from the first moment. But time and experience have rowed in favor of the scientific community: there is "robust" evidence of the safety of vaccines in this population group, all the voices consulted insist. In fact, after reviewing several studies that included some 65,000 pregnancies at different stages, the European Medicines Agency (EMA) has concluded that there is "growing evidence" that messenger RNA vaccines (Pfizer's and Moderna) do not cause complications in pregnancy, neither for pregnant women nor for their babies.Experts invite pregnant women to be vaccinated with the full schedule and also receive the third dose, and remember that the risk of hospitalization and death if they contract covid is much higher.

Nuria Ramírez, 40, was vaccinated with the first dose of the Pfizer vaccine in September, when she was 14 weeks pregnant.

"I didn't get vaccinated before, when it was due to my age group, because it coincided with a fertility treatment and they told me to wait until it was over," she explains.

At first, they recommended that she be vaccinated in the 20th week of pregnancy, but, after completing the first trimester, they already called her to make an appointment: “I had no doubts.

All my gynecologists recommended that I get vaccinated.”

And he celebrates it: the covid passed in December, but in a mild way, "with some snot, cough" and a low-grade fever.

Nothing more.

She, who has a high-risk pregnancy, with preeclampsia (high blood pressure) and gestational diabetes, overcame the infectious disease without further shock.

More information

Covid increases the risk of pregnancy complications by 50%, according to a study

What gynecologists had no doubt for a long time is that pregnant women are at greater risk of complications if they become infected. The probability that they will be infected is the same as that of the general population, but if they get sick with covid, the scenario looks uglier than for a person who is not pregnant. The international Intercovid study revealed that the coronavirus increases the risk of complications during pregnancy for mothers and babies by 50%. The research, published in the journal Jama, concluded that pregnant women diagnosed with covid had a higher risk of maternal and neonatal morbidity and mortality, points out Anna Suy, head of the Obstetrics section of Vall d'Hebron: "If they have covid, it is more frequent that they end up hospitalized, that they enter intensive care (ICU),who have a premature birth due to medical indication [to improve the health status of the mother] or who suffer from high blood pressure during pregnancy”, he lists.

José Villar, professor of Perinatal Medicine at the University of Oxford and one of the authors of the Intercovid points out that, currently, “there is no doubt that in pregnant women not vaccinated with covid the risk to the mother and the fetus increases considerably compared to rest of the pregnant women. And this is explained by several reasons. Starting because "there is a mechanical component, since at the end of pregnancy, with the increase in the size of the uterus, there is an effect on the lung and a respiratory alteration," says Villar. Óscar Martínez, gynecologist at the Puerta del Hierro Hospital in Madrid and principal investigator of the Obscovid registry, which analyzes the impact of the virus on pregnant women,He also adds that "the virus really likes the endothelium [the cells that cover the inner face of the blood vessels] and produces many vascular alterations and the placenta is tremendously vascularized, so there are more serious pre-eclampsia."

Last summer, the fifth wave crystallized the risks outlined by scientific studies. It was “the wave of pregnant women”, as they called it in some hospitals, due to the number of pregnant women in the ICU that they had to attend to. “It was terrifying. 50% of those who were admitted due to covid ended up in the ICU”, recalls Suy. In his hospital, a reference to care for pregnant women with covid, 74 women were admitted to intensive care. At that time, vaccination was still beginning to reach women of childbearing age and there was a strong controversy among professionals, who even issued contradictory recommendations. For example, although the Ministry of Health recommended vaccination for all pregnant women, the World Health Organization (WHO),qualified the recommendation to “when the benefits of vaccination for pregnant women outweigh the potential risks”. Guillermo Antiñolo, head of the Obstetrics and Gynecology service at the Virgen del Rocío Hospital in Seville, remembers those days as "a perfect storm": "The delta was more contagious, the vaccination rate was still low and many pregnant women were not vaccinated, there were an unsubstantiated backlash from some professionals and a coherent response was lacking.”there was an unsubstantiated backlash from some professionals and a coherent response was lacking.”there was an unsubstantiated backlash from some professionals and a coherent response was lacking.”

Now there are fewer discrepancies, points out Toni Payà, head of the Hospital del Mar Obstetrics and Gynecology Service: “There is no longer so much resistance, neither from professionals nor from patients.

There are very few unvaccinated pregnant women, it is almost anecdotal”, resolves the specialist.

Martínez agrees: “The lack of information has been reduced and there is more unanimity on the part of the authorities.

The information is homogeneous and, although there are niches that are less permeable to changes, most of them are aware”.

Although the data of a randomized study with the Pfizer vaccine in pregnant women have not yet been published, prospective and observational studies support the benefits of the vaccine.

For example, research published in the journal Nature confirmed, after comparing more than 10,800 vaccinated pregnant women with as many others with the same unvaccinated socio-demographic characteristics, that the Pfizer vaccine has a high vaccine effectiveness —above 90%— in pregnant women , similar to that expected in the general population.

Another study in Israel, published in the journal

, found that vaccination during pregnancy "has no adverse effects on the course and outcomes of pregnancy."

And along these lines, another American analysis reported that the risk of spontaneous abortion is not greater after vaccination.

The EMA also includes in its analysis of the published scientific literature that "no sign of an increased risk of pregnancy complications, spontaneous abortions, premature births or adverse effects on fetuses after vaccination" has been found with messenger RNA drugs .

And the side effects are similar to those in the general population, he adds: tiredness, headaches, pain, redness or swelling at the injection site, muscle pain and chills.

Third doses

Now, the misgivings and “the recurring questions of pregnant women in the consultation”, explains Martínez, focus on the third dose. The Ministry of Health recommends it, although in the Vaccination Strategy it admits that the information on booster doses in pregnant women is “very limited”. The experts consulted clarify, however, that there is nothing to worry about. “What is safe for the second dose is safe for the third. There is no objective argument that calls into question the safety of the third dose because it is a drug that women have already faced”, settles the gynecologist at Puerta del Hierro.

The Federation of Scientific and Medical Associations of Spain (Facme), which advises the Government on the vaccination campaign, endorses vaccination in pregnant women and also the third doses: preferably, punctures with messenger RNA vaccines and the booster dose, at six months of the second. Cristina Avendaño, a member of Facme, recalls that the vaccine protects against serious infection and in the midst of the sixth wave, the greater protection, the better: “We must remember, at this time of unleashed infection, that the third dose improves protection against omicron ”. The expert calls for calm with suspicions regarding the booster dose: “Nothing indicates that the third dose has more risk than the second. It is a dose that is administered during pregnancy and we benefit from the experience that the injection of the first and second doses has given.No specific safety data from the third dose is needed."

The only suggestion that Facme makes is that, although there is no contraindication to injecting the third dose in any trimester of pregnancy, it is "preferred" to administer it after week 14 of gestation. Due to “a principle of prudence”, the experts consulted point out, rather than because some damage was detected or suspected due to the puncture in the first trimester. Avendaño points out that the first three months of pregnancy are "the moment of greatest vulnerability in the development of the fetus" and attempts are made to avoid "any fever or stress factor" that affects that moment. Payà agrees: "What interests us is that she arrives vaccinated in the third trimester, which is where the most problems have occurred if she becomes infected."

But the third dose raises doubts, even among pregnant women convinced of vaccination. Especially if they have recently passed the covid. According to Health, in these cases, the booster dose will be administered “at least four weeks after the infection”, but some experts consider it too soon. Nuria Ramírez, for example, has just turned a month after being infected with covid, but since she is in the 34th week of pregnancy and, predictably, they will cause her labor in the 38th, she prefers to wait to give birth: “I want everything to go well in the part and I don't want one more puncture before. I'll wait a bit." And Olivia (not her real name), 39, thinks the same: she was infected at Christmas and they have already sent her the notice to make an appointment for the booster dose: “I am pro-vaccine, but I am not convinced about the third dose so Following.I'm going to wait a little longer," he says. Regarding these cases, Martínez defends following the vaccination strategy. To avoid risks: "Reinfection was rare after covid until the omicron appeared," he warns.

Regarding the third doses in general, the experts consulted are blunt. Vaccines are “extremely effective”, insists Villar: “The evidence is clear. These vaccines have been studied in more than 250,000 women and no altered effect has been found. Also, these vaccines do not have any viral agents that can cause anything. The logical evidence indicates that there is no element of risk, even with the third dose.” The British Government has launched a campaign to encourage punctures among pregnant women and has warned that data from the United Kingdom Obstetric Surveillance System show that 96.3% of pregnant women admitted to hospital with covid symptoms between May and October 2021 were unvaccinated, a third of whom required respiratory support.

On a small scale, Suy also points out that patients who are now admitted in serious condition are not vaccinated.

Antiñolo adds that now "there are many infections but not serious illness and many admissions with covid, but not covid."

Without vaccines, experts agree, the scenario would have been very different.

And much worse.