Can COVID-19 vaccination cause miscarriage in pregnant women?

Over the past two years, a massive vaccination campaign against severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) was initiated to contain the coronavirus disease 2019 (COVID-19) pandemic. However, the rapid development and Emergency Use Authorization (EUA) of the COVID-19 vaccine has raised concerns about its efficacy, safety, and long-term effects. In particular, pregnant women and women planning to become pregnant were reluctant to get vaccinated.

study: Risk of miscarriage after COVID-19 vaccination: a systematic review and meta-analysis.Image Credit: Blue Planet Studios/Shutterstock

Background

Initially, pregnant women were excluded from clinical studies designed to evaluate. efficacy of COVID-19 vaccine. As a result, limited evidence was available regarding the safety of vaccines during pregnancy. The majority of health authorities now report that COVID-19 vaccination is safe for pregnant women. This observation is based on the lower risk of poor pregnancy outcome in women who received the COVID-19 vaccine compared to unvaccinated pregnant women.

Several studies have shown a potential risk of cross-reactivity between SARS-CoV-2 spike (S) protein antibodies and human syncytin-1 protein in trophoblast tissue after mRNA vaccination. This can cause placental damage. Furthermore, autoreactive antibodies to syncytin-1 can lead to early abortion. Nonetheless, detailed characterization of the S protein structure and amino acid sequencing revealed a slight homology between the S protein antibody generated after vaccination and syncytin-1, suggesting the safety of the COVID-19 vaccine. gender was shown.

About research

Scientists recently examined existing literature to assess miscarriage and live birth rates in pregnant women who received the COVID-19 vaccine. This review is human reproduction journal.

For this study, we obtained all relevant data from MEDLINE, Cochrane CENTRAL, and EMBASE up to June 2022. The authors considered all studies related to miscarriage, birth and ongoing pregnancy in women who received the COVID-19 vaccine. Animal studies and studies reporting nonclinical results in human participants were excluded.

A total of 505 relevant citations were considered, including randomized controlled trials (RCTs) and observational studies. However, 21 studies meeting all criteria were selected.

Combining all studies, the pregnancy outcomes of 149,685 women were studied. Participants were six cytoplasmic cytoplasms manufactured by Pfizer-Biontech (BNT162b2 mRNA), Moderna (mRNA-1273), Janssen (Ad26.COV2.S), AstraZeneca (ChAdOx1 nCoV184 19), and SinoPharm (BBIBP-CorV). I received one of the COVID-19 vaccines. ), and Sinovac (CoronaVac). Overall, the studies considered in this review showed a low to moderate risk of bias.

Investigation result

The average miscarriage rate among pregnant women who received the COVID-19 vaccine was 9%. The risk of miscarriage in the COVID-19 vaccinated group compared to the unvaccinated group showed no significant difference in miscarriage rates between the two groups. Moreover, both groups showed similar rates of ongoing pregnancies or live births.

Limitations

Heterogeneity in study design and patient characteristics, along with risk of bias, limited the generalizability of current meta-analyses. It also highlights the need for more high-quality research in pregnant women in the future. Most studies performed suboptimal protocols, resulting in mixed findings. This limited our analysis of high-quality evidence. Low-quality data also reduced the certainty of pooled estimates, especially for pregnancy outcomes. Incidences of stillbirth and ectopic pregnancy were not reported in any of the studies considered.

Several factors may contribute to overall miscarriage rates during the pandemic, including mode of conception, ethnicity, and access to obstetric services during lockdown periods. The majority of studies have been related to short-term assessments of the safety of COVID-19 vaccines. These studies do not provide insight into long-term outcomes of pregnancy.

Conclusion and future prospects

No apparent increased risk of miscarriage was observed among pregnant women who received the COVID-19 vaccine. This rate was consistent with miscarriage rates in the general population prior to the COVID-19 pandemic. However, the certainty of this observation is low due to inconsistent data.

In the future, the short- and long-term safety and efficacy of all COVID-19 vaccines in pregnant women and their offspring should be evaluated. In addition, large, controlled, prospective cohort studies, along with epidemiological and translational studies, should be conducted to analyze the efficacy and safety of different COVID-19 vaccination programs.

The authors recommend that future studies follow a standardized reporting system for core outcomes: miscarriage, fertility, and pregnancy. This greatly reduces research waste.