Spontaneous abortion after vaccine

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Risk of spontaneous abortion after vaccination

Risk of Stillbirth Among Women With and Without COVID-19 at Delivery Hospitalization — United States, March 2020–September 2021


Sixth, it was not possible to assess vaccination status in this analysis.

However, because COVID-19 vaccines are highly effective, and COVID-19 vaccination coverage among pregnant women was approximately 30% as of July 2021,

most women with COVID-19 at delivery were likely unvaccinated.

Etiology of Spontaneous Abortion



cytomegalovirus, herpesvirus, parvovirus, and rubella virus

live vaccines, not in pregnancy

non-live vaccines have previously been shown to be safe in pregnancy (flu and whooping cough)


Genetic abnormalities

Immunologic abnormalities

Major trauma

Uterine abnormalities

Most often, the cause is unknown

Risk factors for spontaneous abortion include

Age more than 35

History of spontaneous abortion
Cigarette smoking

Use of certain drugs (eg, cocaine, alcohol, high doses of caffeine)

A poorly controlled chronic disorder (eg, diabetes, hypertension, overt thyroid disorders) in the mother

Spontaneous Abortion Following COVID-19 Vaccination During Pregnancy (8 September 2021)


Concerns regarding risks of spontaneous abortion may be a barrier to vaccination during pregnancy

We present findings from case-control surveillance of COVID-19 vaccination during pregnancy and spontaneous abortion.


Data from 8 health systems (Kaiser Permanente: Washington, Northwest, Northern California, Southern California, and Colorado; Denver Health; HealthPartners; and Marshfield Clinic, Wisconsin)

4-week surveillance periods from December 15, 2020, through June 28, 2021

Ongoing pregnancies between 6 and 19 weeks’ gestation


Of 105,446 pregnancies

13,160 spontaneous abortions

92,286 ongoing pregnancies were identified

Vaccine during pregnancy and before 20 weeks’ gestation

7.8% of women received 1 or more BNT162b2

6.0% received 1 or more mRNA-1273 (Moderna)

0.5% received an Ad26.COV.2.S (Janssen)

A COVID-19 vaccine was received within 28 days prior to an index date

8.0% of ongoing pregnancy periods

8.6% of spontaneous abortions

Spontaneous abortions did not have an increased odds of exposure to a COVID-19 vaccination in the prior 28 days compared with ongoing pregnancies

adjusted odds ratio, 1.02

Results were consistent for mRNA-1273 and BNT162b2 and by gestational age group


Despite limitations, these data can be used to inform vaccine recommendations and to counsel patients.

Receipt of mRNA Covid-19 Vaccines and Risk of Spontaneous Abortion

(14 October 2021)


Singleton pregnancy, n = 2,456

Centers for Disease Control and Prevention (CDC)


v-safe Covid-19 vaccine pregnancy registry

who had received at least one dose of an mRNA Covid-19 vaccine,

either before conception or before 20 weeks of gestation,

52.7% had received the BNT162b2 vaccine

The cumulative risk of spontaneous abortion from 6 to less than 20 weeks of gestation was 14.1%



The estimated risks (14.1% overall and 12.8% in age-standardized analyses) are consistent with the risks of spontaneous abortion reported in the general population


COVID-19 vaccines are recommended in pregnancy.

Vaccination is the best way to protect against the known risks of COVID-19 in pregnancy for both women and babies,

including admission of the woman to intensive care and premature birth of the baby

You should not stop breastfeeding in order to be vaccinated against COVID-19.

Women trying to become pregnant do not need to avoid pregnancy after vaccination,

there is no evidence to suggest that COVID-19 vaccines will affect fertility.

So far (11th October)

more than 82,000 pregnant women in England have received at least one dose of COVID-19 vaccination and

Public Health Scotland have reported that more than 19,000 pregnant women have received a vaccine,

with no serious adverse effects recorded.

Research from across six studies in four countries,

involving more than 40,000 pregnant women,

shows having the vaccine does not increase the risk of miscarriage, preterm birth, stillbirth, nor does it increase the risk of a small-for-gestational age baby,

or the risk of congenital abnormalities.