For more information: www.cdc.gov/COVID19

COVID-19 vaccine safety in pregnancy:

Updates from the v-safe COVID-19 vaccine 

pregnancy registry 

Sep 22, 2021

Christine Olson MD, MPH

v-safe COVID-19 vaccine pregnancy registry

CDC COVID-19 Vaccine Task Force
Disclaimer

 The findings and conclusions in this report are those of the authors and do 

not necessarily represent the official position of the Centers for Disease 

Control and Prevention (CDC)

 Mention of a product or company name is for identification purposes only 

and does not constitute endorsement by CDC

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V-safe pregnancy registry enrollment

Pregnant at Time 

of Vaccination

Vaccinated during 

Periconceptional 

Period

*Pregnancy questions in v-safe assessments on first survey after each dose and on post-vaccination days 21 and 42 and months 3, 6, and 12

ŦEligibility determined from verbal interviews and responses to 3-question web-based v-safe follow-up survey received prior to May 31, 2021. Eligible individuals 

received COVID-19 vaccination during pregnancy or periconceptional period (≤ 30 days before the first day of the last menstrual period before pregnancy) 

Pregnancies

reported to v-safe*

Consent for 

registry enrollment 

and follow-up

Eligibility screeningŦ

Individuals 

Reporting 

Pregnancy

Eligible 

Individuals
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V-safe pregnancy registry active follow-up

 Participants interviewed during each trimester, postpartum, and during early infancy
V-safe pregnancy registry participants, by vaccine 

manufacturer as of September 13, 2021, N=5096

43.9% 50.7%

5.4%

PfizerBioNTech

N=2584

Moderna

N=2236

Janssen/J&J

N=276

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Timing of first COVID-19 vaccination during periconception or 

pregnancy among v-safe pregnancy registry participants

Periconceptional

N=277 

(5.4%)

Data as of September 13, 2021

*Eligibility dates missing for 3 participants

Definitions: Periconceptional: ≤30 days before the first day of the last menstrual period before pregnancy; 

First trimester: 1st day of LMP to <14 weeks gestational age; Second trimester: 14-28 weeks; Third trimester: ≥28 weeks

Third 

Trimester

N=1428

(28.0%)

N=2119

(41.6%)

N=1269

(24.9%)

Second 

Trimester

First 

Trimester

Among 5093 participants*

6
0

100

200

300

400

500

600

700

Number of Participants

Expected Delivery Month

Periconception

1st Trimester

2nd Trimester

3rd Trimester

Estimated month of delivery among enrolled participants, by timing of 

1st COVID-19 vaccination received during periconception or pregnancy

Timing of 1st

COVID-19 

vaccination

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Postpartum and Infant 

follow-up window^

Estimated date of delivery 

not yet reached

0

100

200

300

400

500

600

700

Number of Participants

Expected Delivery Month

Periconception

1st Trimester

2nd Trimester

3rd Trimester

Estimated month of delivery among enrolled participants, by timing of 

1st COVID-19 vaccination during periconception or pregnancy

Timing of 1st

COVID-19 

vaccination

^Postpartum and infant follow-up interviews lag expected date of delivery by approximately 19 weeks 8
V-safe pregnancy registry participant characteristics

(N=5096 enrolled)

Age Enrolled %

<20 0

20-24 1.1

25-34 65.3

35-44 33.3

>45 0.3

Race/Ethnicity* Enrolled %

Non-Hispanic Black 1.4

Non-Hispanic White 79.4

Non-Hispanic Asian 8.4

Non-Hispanic Other 2.3

Hispanic 8.1

Data as of September 13, 2021 *Race/Ethnicity, Missing/Declined N=20 (of the 5096) 9
V-safe pregnancy registry participant occupation, as 

derived from vaccine priority group question

83.6 87.7 87.0

18.1

5.8 4.1 5.7

22.4

10.1 7.9 7.9

56.0

0.5 0.3 0.3 3.6

0

10

20

30

40

50

60

70

80

90

100

All (N=5096) Pfizer-BioNTech

(N=2584)

Moderna (N=2235) Janssen/J&J (N=277)

Percentage

Healthcare personnel Non-healthcare essential worker Other Missing

Data as of September 13, 2021 10
V-safe pregnancy registry analysis of 

early pregnancy loss
Receipt of mRNA COVID-19 vaccines and risk of 

spontaneous abortion (SAB)*

 Objective: Assess the cumulative risk of SAB after mRNA COVID-19 

vaccination

 Data source: CDC’s v-safe pregnancy registry, COVID-19 vaccination data 

2020–21

 Methods:

• Included 2456 pregnant people enrolled in v-safe pregnancy registry 

‒ Received at least one dose of an mRNA COVID-19 vaccine before 

pregnancy or prior to 20 weeks of pregnancy

‒ Did not have a pregnancy loss before 6 weeks of gestation

• Lifetable methods to examine cumulative risk

*Zauche et al. Receipt of mRNA Covid-19 Vaccines and Risk of Spontaneous Abortion. N Engl J Med. 2021 Sep 8. doi: 10.1056/NEJMc2113891.

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No increased risk of spontaneous abortion (SAB) after COVID-19 

vaccination during pregnancy

 Unadjusted cumulative risk of SAB 

after mRNA COVID-19 vaccination 

14.1%

 Age-standardized cumulative risk 

of SAB:

12.8% (95% CI: 10.8%–14.8%)

– Similar to previously published 

baseline estimates of SAB 

(11%–22%)

 More evidence that mRNA 

COVID-19 vaccination during 

pregnancy is not associated with 

SAB

Zauche et al. Receipt of mRNA Covid-19 Vaccines and Risk of Spontaneous Abortion. N Engl J Med. 2021 Sep 8. doi: 10.1056/NEJMc2113891.

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Cumulative risk of spontaneous abortion in the v-safe pregnancy registry 

and in two historical cohorts

Zauche et al. Receipt of mRNA Covid-19 Vaccines and Risk of Spontaneous Abortion. N Engl J Med. 2021 Sep 8. doi: 10.1056/NEJMc2113891.

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V-safe pregnancy registry infant outcomes 

at birth
0

100

200

300

400

500

600

700

Number of Participants

Expected Delivery Month

Periconception

1st Trimester

2nd Trimester

3rd Trimester

Estimated month of delivery, among enrolled participants, by timing of 

1st COVID-19 vaccination during periconception or pregnancy

Timing of 1st

COVID-19 

vaccination

Note: postpartum and infant follow-up interviews lag expected delivery date by approximately 19 weeks 16
V-safe pregnancy registry enrolled pregnancies included in 

maternal and infant outcomes cohort

Data as of September 13, 2021

5096 enrolled participants

2177 estimated date of delivery 

(EDD) before May 15, 2021

1613 pregnancies

• 501 pending follow-up

• 63 lost to follow-up

• 2912 with EDD after May 15, 2021

• 7 withdrew

1634* Live born infants 30 % 2nd trimester vaccination

70 % 3rd trimester vaccination

* Includes 42 infants from twin gestations

• Participants enrolled in first 

trimester: 1427

• Pregnancies and follow-up 

ongoing; therefore, data are 

incomplete

• Will be included in future 

reports 17
Infant outcomes among v-safe pregnancy registry enrolled 

participants* with pregnancies ending in live birth (N=1634 infants)

Live born infants

All infants

N=1634 (%)

Background rate

%†

Preterm a 99 (6.5) 8-15

Small for gestational age b 45 (2.8) 3.5

Admitted to NICU c 158 (9.7) 9.3

Neonatal or infant death d 0 (0) <1

* Maternal and infant outcomes cohort defined as participants with completed follow-up and expected delivery dates prior to May 15, 2021, to account 

for the lag in ascertaining outcomes at infant 3-month follow-up.

† Preliminary Findings of mRNA Covid-19 Vaccine Safety in Pregnant Persons in NEJM https://www.nejm.org/doi/full/10.1056/nejmoa2104983

a Preterm birth denominator is live births among mothers vaccinated before 37 weeks' gestation (n=1,514 infants)

b Birthweight below the 10th percentile for gestational age and sex using INTERGROWTH-21st Century growth standards

c Among 2019 live births, National Vital Statistics Registry: https://www.cdc.gov/nchs/data/nvsr/nvsr70/nvsr70-02-tables-508.pdf

d Among 2018 live births, National Vital Statistics Registry: https://www.cdc.gov/nchs/data/nvsr/nvsr69/NVSR-69-7-508.pdf 18
Preliminary birth defects data among live born infants 

of participants vaccinated in the 2nd or 3rd trimester

 Most birth defects arise in the first trimester; most pregnancies in the 

registry that were vaccinated in the first trimester are ongoing

 V-safe pregnancy registry participants report birth defects during the 

postpartum interview

– Response to question “Was your baby diagnosed with a birth defect?”

 Reported birth defects were reviewed for inclusion and categorized by birth 

defect experts

 Birth defects were defined as a structural abnormality, chromosome 

anomaly, or genetic syndrome

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Among the 45 infants with birth 

defects:

 Types of reported birth defects 

are consistent with data from 

birth defects surveillance in the 

United States

 No unusual types or clusters of 

birth defects noted

 The v-safe pregnancy registry has 

demonstrated its capability in 

identifying birth defect outcomes 

and their distinct types

Participant reports of birth defects among live born infants of 

participants vaccinated in the 2nd or 3rd trimester (N=1574)

Birth Defect Categories

Specific defects

N=52*

Heart and circulatory system 16

Septal defects 11

Musculoskeletal system 8

Polydactyly and syndactyly 4

Genitalia 7

Hypospadias 5

Kidney and urinary system 5

Cleft lip +/- cleft palate 4

Chromosomal anomalies 4

Trisomy 21 3

Nervous system 3

Respiratory system 2

Other 3

Data as of September 6, 2021

*Among 45 infants who had one or more major birth defect; 6 infants had >1 birth defect; 1 infant was from a twin gestation

v-safe pregnancy registry 20
Closing thoughts on COVID-19 vaccination 

and pregnancy
Closing thoughts

 Accumulating data on the safety of COVID-19 vaccination during 

pregnancy from the v-safe pregnancy registry adds to the growing 

body of evidence of the safety of COVID-19 vaccination during 

pregnancy 

– No evidence of any increase in spontaneous abortion rates

– No evidence of any disproportionate infant outcomes

 CDC will continue to monitor the safety of COVID-19 vaccination 

during pregnancy

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Acknowledgments

 V-safe After Vaccination Health Checker Team

 V-safe COVID-19 Pregnancy Registry Team

 Vaccine Safety Datalink Team

 VAERS Team

 Participants in all of the above vaccine safety monitoring systems

 CDC COVID-19 Vaccine Task Force

Thank you to the many people who continue to contribute to the vaccine 

safety monitoring work

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1-800-CDC-INFO (232-4636)

TTY: 1-888-232-6348 www.cdc.gov

The findings and conclusions in this report are those of the authors and do not necessarily represent the 

official position of the Centers for Disease Control and Prevention.

Thank you!