COVID-19 mRNA Vaccine Pregnancy Watch of the Conservative Midwives Organization

About this data

The purpose of this report is to facilitate information to the public. To date, there is no sufficient evidence on whether or not mRNA vaccine technology is safe during pregnancy. Given this fact, the Conservative Midwives Organization has taken a role of vigilance and awareness regarding miscarriage after vaccination until conclusive safety data is made available. It is not our purpose to create distress, anger, or panic but rather to provide information that aids a bodily autonomy decision in women of reproductive age.

The information contained in the table below was obtained and curated from the Vaccine Adverse Event Reporting System (VAERS) of the United States Department of Health and Human Services (HHS). The table is a simplified version of relevant data from reports of pregnancy loss occurring after administering mRNA vaccine against COVID-19 manufactured by Moderna or Pfizer/BioNTech. The source datasets are publicly available.  

How to interpret this data

This information was collected from adverse event reports voluntarily provided by healthcare professionals and patients. The statements are based on clinical events, which are not sufficient to get to a clear conclusion. However, some circumstances, such as the time between the vaccine administration and miscarriage, can suggest a relationship between the two. That being said, many pregnancy losses are of unknown cause, and several factors can lead to miscarriage. An average of 9-20% of women between 20-35 years old will experience miscarriage under 13 weeks of pregnancy, and the risk increases with age (DynaMed, First Trimester Pregnancy Loss).  

A conclusive determination of the cause of miscarriage would require resources beyond clinical history, such as hormonal, anatomical, microscopical, and molecular studies, among other assessments. Our understanding is that the HHS is following up on some of the cases to obtain a more detailed scenario and get to a conclusion.


Conservative Midwives Organization Grade:

Our research team evaluated every report presented in this dataset and, based on clinical experience, knowledge, and available research, graded the cases in the following manner:

A= Miscarriage unlikely to be caused by the vaccine. Information provided suggests another cause.

B= Lack of sufficient information. Relationship of miscarriage with the vaccine cannot be determined but it cannot be excluded.

C = Lack of sufficient information, but information available raises suspicion of miscarriage related to the vaccine.

D= Highly suspicious. The timing of miscarriage as related to vaccine administration is suggestive of harm. More information is needed to confirm suspicions.

Entity’s conclusion: Response of the entity holding the reports (i.e., HHS VAERS). This is the part of their response that provides a conclusion; other comments might be omitted.

Estimated gestational age: Weeks of pregnancy at the time that the vaccine dose was administrated. In some reports, the number of weeks was given; in others, we calculated it with MedScape or MDCalc online pregnancy dates calculators using given information of last menstrual period or estimated due date.

Time between vaccine and onset of miscarriage: This is the time from when the vaccine was administered to the date when the patient or healthcare provider first reports miscarriage.


Our report is an ongoing project; we will be adding information from other databases as well as posting clinical details from the HHS VAERS. This table will be updated every two weeks.

For errata and broken links, please inform us through our website’s contact form.   

To report a case email us at

COVID-19 mRNA Vaccine Pregnancy Watch Dataset

Conservative Midwives Organization
Database EntityCase IDVaccineIndividual submitting the reportEstimated gestational ageTime between vaccine and onset of miscarriageEntity’s conclusionConservative Midwives Organization Grade
HHS VAERS925639PFIZER\BIONTECHHealth Professional3 weeks7 days“The information currently provided is too limited to make a meaningful medical assessment hence, the events are conservatively assessed as related to the suspect drug BNT162B2 until further information becomes available…”B
HHS VAERS928892PFIZER\BIONTECHPatient6 weeks19 daysN/AA
HHS VAERS932107PFIZER\BIONTECHUnknown6 weeks and 4 days2 daysN/A  D
HHS VAERS943837PFIZER\BIONTECHPatient6 weeks5 daysN/AB
HHS VAERS949729PFIZER\BIONTECHUnknown6 weeks11 daysN/AA
HHS VAERS950562PFIZER\BIONTECHPatient5 weeks9 daysN/AB
HHS VAERS 953086PFIZER\BIONTECHPhysician3 weeks14 days“The data on BNT162B2 administered to pregnant women is insufficient to make a meaningful medical assessment hence, the events are conservatively assessed as related to the suspect drug BNT162B2 until further information becomes available.”B
HHS VAERS955432PFIZER\BIONTECHPatient7 weeks and 4 days4 daysN/A.C
HHS VAERS962952MODERNAUnknownN/A1 dayN/A.D
 965558PFIZER\BIONTECHNurse4 weeks20 days“Based on the temporal relationship, the association between the event miscarriage with BNT162b2 can not be complete excluded.“B
HHS VAERS966887MODERNAPatientPregnancy diagnosis 5 days after first doseUnclear; estimated 5 weeksN/A.B
HHS VAERS 990450PFIZER\BIONTECHNurse3 weeks5 days“Based on the available information, a causal relationship between event  miscarriage after the second COVID-19 vaccination and BNT162B2 (PFIZER-BIONTECH COVID-19 VACCINE) cannot be completely excluded.”C
HHS VAERS1004202MODERNAHealth Professional4 weeks and 5 daysN/A“…there is not enough evidence to assess that that there was a miscarriage and is also unlikely to be associated with mRNA-1273 administration. The event of vaccine exposure during pregnancy is considered not applicable.”A
HHS VAERS1006011PFIZER\BIONTECHPatient9 weeks and 2 days5 daysN/AB
HHS VAERS1007832PFIZER\BIONTECHPatient8 weeks21 daysN/AC
HHS VAERS1010528PFIZER\BIONTECHPatient’s relative3 weeks5 days“Based on the temporal relationship, the association between the event miscarriage with BNT162b2 can not be completely excluded.”C
HHS VAERS1015666PFIZER\BIONTECHNurse6 weeks11 days“Based on temporal association, a possible contributory role of BNT162B2 cannot be completely excluded for reported miscarriage.”B
Conservative Midwives Organization Research Team

N/A = Not available or information not provided.

Data sources:


To report a case email us at

Last updated: 2/23/2021

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