Covid-19 Vaccination right through Pregnancy and First-Trimester Miscarriage | NEJM
To the Editor:
Pregnant girls with coronavirus illness 2019 (Covid-19) are at higher possibility for opposed results, and Covid-19 vaccination is really helpful right through being pregnant.1,2 However, protection records on Covid-19 vaccination right through being pregnant stay restricted.3,4
We carried out a casecontrol learn about with records from Norwegian registries on first-trimester pregnancies, Covid-19 vaccination, background traits, and underlying well being stipulations (Supplementary Methods and Tables S1 thru S3 within the Supplementary Appendix, to be had with the whole textual content of this letter at NEJM.org). We known all girls who have been registered between February 15 and August 15, 2021, as having had a miscarriage prior to 14 weeks of gestation (case sufferers) and the ones with a number one carebased affirmation of ongoing being pregnant within the first trimester (controls). In Norway, even supposing vaccination right through the primary trimester isn’t really helpful excluding in girls with underlying possibility stipulations, girls now not but conscious that they have been pregnant might nonetheless be vaccinated within the first trimester. We estimated odds ratios with 95% self belief durations for Covid-19 vaccination inside of 5-week and 3-week home windows prior to a miscarriage or ongoing being pregnant, adjusting for womens age, nation of start, marital standing, instructional stage, family source of revenue, collection of kids, employment in a well being care career, underlying possibility stipulations for Covid-19, earlier check certain for critical acute breathing syndrome coronavirus 2, and calendar month.
Among 13,956 women with ongoing pregnancies (of whom 5.5% were vaccinated) and 4521 women with miscarriages (of whom 5.1% were vaccinated), the median number of days between vaccination and miscarriage or confirmation of ongoing pregnancy was 19 (Fig. S2). Among women with miscarriages, the adjusted odds ratios for Covid-19 vaccination were 0.91 (95% confidence interval [CI], 0.75 to 1.10) for vaccination in the previous 3 weeks and 0.81 (95% CI, 0.69 to 0.95) for vaccination in the previous 5 weeks (Table 1). The results were similar in an analysis that included all available vaccine types (Table S5), in an analysis stratified according to the number of doses received (one or two) (Table S6), and in sensitivity analyses limited to health care personnel (for whom vaccination was routinely recommended other than in the first trimester) or women with at least 8 weeks of follow-up after confirmed pregnancy (to exclude subsequent pregnancy loss) (Table S7).
A limitation of our report is that the registry lacks information on gestational age at the time of early pregnancy registration, and thus we could not match case patients and controls according to gestational age. However, most recognized miscarriages are known to occur between pregnancy weeks 6 and 10,5 a period that is similar to the gestational ages at which women in Norway consult a physician to confirm pregnancy (Fig. S1). Also, only approximately 40% of women in Norway have a primary care appointment to confirm pregnancy, but the characteristics of these women appear to be similar to those of women who do not have a registered pregnancy confirmation (Table S4). We cannot address associations between vaccination and miscarriages that were not clinically recognized. Although adjustment for potential confounders had minimal effect on our results, the registry does not include information on lifestyle and other factors that might confound our findings (see Supplementary Appendix).
Our study found no evidence of an increased risk for early pregnancy loss after Covid-19 vaccination and adds to the findings from other reports supporting Covid-19 vaccination during pregnancy.3,4
Maria C. Magnus, Ph.D.
Hkon K. Gjessing, Ph.D.
Helena N. Eide, M.D.
Norwegian Institute of Public Health, Oslo, Norway
Allen J. Wilcox, M.D., Ph.D.
National Institute of Environmental Health Sciences, Durham, NC
Deshayne B. Fell, Ph.D.
School of Epidemiology and Public Health, University of Ottawa, Ottawa, ON, Canada
Siri E. Hberg, M.D., Ph.D.
Norwegian Institute of Public Health, Oslo, Norway
Supported in part by the
Disclosure forms provided by the authors are available with the full text of this letter at NEJM.org.
This letter was published on October 20, 2021, at NEJM.org.
1. Centers for Disease Control and Prevention. COVID-19 vaccines while pregnant or breastfeeding. August 11, 2021 (https://www.cdc.gov/coronavirus/2019-ncov/vaccines/recommendations/pregnancy.html).
2. National Health Service. Pregnancy, breastfeeding, fertility and coronavirus (COVID-19) vaccination. September 2, 2021 (https://www.nhs.uk/conditions/coronavirus-covid-19/coronavirus-vaccination/pregnancy-breastfeeding-fertility-and-coronavirus-covid-19-vaccination/).
3. Zauche LH, Wallace B, Smoots AN, et al. Receipt of mRNA Covid-19 vaccines and risk of spontaneous abortion. N Engl J Med 2021;385:1533–1535.
4. Kharbanda EO, Haapala J, DeSilva M, et al. Spontaneous abortion following COVID-19 vaccination during pregnancy. JAMA 2021 September 8 (Epub forward of print).
5. Mukherjee S, Velez Edwards DR, Baird DD, Savitz DA, Hartmann KE. Risk of miscarriage among black women and white women in a U.S. prospective cohort study. Am J Epidemiol 2013;177:1271–1278.
|Vaccination Status||5-Week Exposure Window||3-Week Exposure Window|
|Ongoing Pregnancies||Miscarriages||Unadjusted Odds Ratio (95% CI)||Adjusted Odds Ratio (95% CI)*||Ongoing Pregnancies||Miscarriages||Unadjusted Odds Ratio (95% CI)||Adjusted Odds Ratio (95% CI)*|
|Among all girls|
|Vaccinated||772||231||0.92 (0.791.07)||0.81 (0.690.95)||449||146||1.00 (0.831.21)||0.91 (0.751.10)|
|Among well being care staff|
|Vaccinated||261||75||0.92 (0.701.20)||0.93 (0.701.22)||147||43||0.94 (0.661.33)||0.92 (0.641.32)|
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