Viki Male
@vikilovesfacs.bsky.social
Immunology of the menstrual cycle and pregnancy.
Lovely to finally meet you IRL too!
January 29, 2026 at 9:07 PM
Lovely to finally meet you IRL too!
Thank you so much for inviting me! It was great to chat to so many inspiring scientists!
January 29, 2026 at 9:06 PM
Thank you so much for inviting me! It was great to chat to so many inspiring scientists!
So this reports on the combined effect on fertility and pregnancy - none. If we want to know those effects separately, we have to look elsewhere... 3/3
Explainer on COVID19 vaccine and fertility.docx
Explainer on COVID vaccination, fertility, pregnancy and breastfeeding Viki Male, Associate Professor in Reproductive Immunology at Imperial College London [email protected] @VikiLovesFACS Last ...
docs.google.com
January 23, 2026 at 3:22 PM
So this reports on the combined effect on fertility and pregnancy - none. If we want to know those effects separately, we have to look elsewhere... 3/3
But you have to hunt in the supplementary for it.
Important also to realise that this approach effectively looks at effects on pregnancy on the left side of the curve (where ppl vaccinated are already pregnant) and on fertility on the right (vaccination before pregnancy). 2/
Important also to realise that this approach effectively looks at effects on pregnancy on the left side of the curve (where ppl vaccinated are already pregnant) and on fertility on the right (vaccination before pregnancy). 2/
January 23, 2026 at 3:22 PM
But you have to hunt in the supplementary for it.
Important also to realise that this approach effectively looks at effects on pregnancy on the left side of the curve (where ppl vaccinated are already pregnant) and on fertility on the right (vaccination before pregnancy). 2/
Important also to realise that this approach effectively looks at effects on pregnancy on the left side of the curve (where ppl vaccinated are already pregnant) and on fertility on the right (vaccination before pregnancy). 2/
I actually reviewed this one! I was satisfied with the methods but I do felt it struggled for the extremely short format the journal required.
To my mind, the most important finding is the Cox proportional hazards model, showing no difference in time to childbirth by vaccination status... 1/
To my mind, the most important finding is the Cox proportional hazards model, showing no difference in time to childbirth by vaccination status... 1/
January 23, 2026 at 3:18 PM
I actually reviewed this one! I was satisfied with the methods but I do felt it struggled for the extremely short format the journal required.
To my mind, the most important finding is the Cox proportional hazards model, showing no difference in time to childbirth by vaccination status... 1/
To my mind, the most important finding is the Cox proportional hazards model, showing no difference in time to childbirth by vaccination status... 1/
Thanks! We hope people find it useful!
January 16, 2026 at 10:08 AM
Thanks! We hope people find it useful!
Thanks to the IMPRINT network for supporting this project, @ukri.org for funding and colleagues @drbethholder.bsky.social and Sara Barnett. You've all been great to work with!
January 16, 2026 at 10:02 AM
Thanks to the IMPRINT network for supporting this project, @ukri.org for funding and colleagues @drbethholder.bsky.social and Sara Barnett. You've all been great to work with!
We've also curated a collection of resources for midwives and other healthcare professionals, to help make conversations about this important topic easier and more impactful.
Please take a look and share with your patients and colleagues! 2/
Please take a look and share with your patients and colleagues! 2/
January 16, 2026 at 10:02 AM
We've also curated a collection of resources for midwives and other healthcare professionals, to help make conversations about this important topic easier and more impactful.
Please take a look and share with your patients and colleagues! 2/
Please take a look and share with your patients and colleagues! 2/
…it means we can’t tell what is due to infection and what is due to other factors relating to the pandemic. They had 65 pandemic-era but (apparently) uninfected pregnancies that I don’t see them reporting on. I would really have liked to know how these babies were! 2/2
January 7, 2026 at 7:33 AM
…it means we can’t tell what is due to infection and what is due to other factors relating to the pandemic. They had 65 pandemic-era but (apparently) uninfected pregnancies that I don’t see them reporting on. I would really have liked to know how these babies were! 2/2
I am thank you!
Just read this. One thing that annoys me is that they only compare babies born following infection to pre-pandemic babies. I see the logic in that (you can’t be sure that people who weren’t infected in the pandemic really weren’t infected!) but… 1/
Just read this. One thing that annoys me is that they only compare babies born following infection to pre-pandemic babies. I see the logic in that (you can’t be sure that people who weren’t infected in the pandemic really weren’t infected!) but… 1/
January 7, 2026 at 7:29 AM
I am thank you!
Just read this. One thing that annoys me is that they only compare babies born following infection to pre-pandemic babies. I see the logic in that (you can’t be sure that people who weren’t infected in the pandemic really weren’t infected!) but… 1/
Just read this. One thing that annoys me is that they only compare babies born following infection to pre-pandemic babies. I see the logic in that (you can’t be sure that people who weren’t infected in the pandemic really weren’t infected!) but… 1/
I tried but never really got into things here! I think I never got my notifications set up quite right, but got one for this. Certainly something that’s worth keeping an eye on. Thanks for sharing.
January 6, 2026 at 6:26 PM
I tried but never really got into things here! I think I never got my notifications set up quite right, but got one for this. Certainly something that’s worth keeping an eye on. Thanks for sharing.
Until very recently, the CDC was doing this, but specifically focused on the risk of COVID in babies, rather than obstetric outcomes. With their remit being curtailed, rather than extended, I don’t see us having answers to this anytime soon. 2/2
November 3, 2025 at 11:07 PM
Until very recently, the CDC was doing this, but specifically focused on the risk of COVID in babies, rather than obstetric outcomes. With their remit being curtailed, rather than extended, I don’t see us having answers to this anytime soon. 2/2
To my knowledge, no. One big challenge is that we no longer have the testing infrastructure to know who has or hasn’t had COVID and follow up outcomes. Another way to approach the question would be to look at outcomes in vaccinated vs unvaccinated pregnancies. 1/
November 3, 2025 at 11:04 PM
To my knowledge, no. One big challenge is that we no longer have the testing infrastructure to know who has or hasn’t had COVID and follow up outcomes. Another way to approach the question would be to look at outcomes in vaccinated vs unvaccinated pregnancies. 1/
But these stats on their own don’t convince me we’re seeing problems of repeat COVID infection in these services, and also don’t chime with what we’re seeing on the ground: business pretty much as usual, albeit that services are underfunded and understaffed (so… business as usual!) 12/12
October 19, 2025 at 1:47 PM
But these stats on their own don’t convince me we’re seeing problems of repeat COVID infection in these services, and also don’t chime with what we’re seeing on the ground: business pretty much as usual, albeit that services are underfunded and understaffed (so… business as usual!) 12/12
Formal analyses of HES can be done, and this is one of the ways we found that COVID vaccination was safe in pregnancy, and put a numerical value on the harm of infection at the height of the pandemic. As I’ve said, I’d like to see an updated analysis. 11/11
October 19, 2025 at 1:45 PM
Formal analyses of HES can be done, and this is one of the ways we found that COVID vaccination was safe in pregnancy, and put a numerical value on the harm of infection at the height of the pandemic. As I’ve said, I’d like to see an updated analysis. 11/11
So from all of this, I will say the same as I did when people were using HES to try and claim an increase in certain obs and gynae problems due to COVID vaccination.
So much goes into HES that you can’t use the raw figures to test these kinds of ideas. 10/
So much goes into HES that you can’t use the raw figures to test these kinds of ideas. 10/
October 19, 2025 at 1:42 PM
So from all of this, I will say the same as I did when people were using HES to try and claim an increase in certain obs and gynae problems due to COVID vaccination.
So much goes into HES that you can’t use the raw figures to test these kinds of ideas. 10/
So much goes into HES that you can’t use the raw figures to test these kinds of ideas. 10/
There’s also increased awareness about endometriosis, which is great! And longer waiting lists to see the gynae service - I am hearing years in some trusts - which is not. But both of these will cause an increase in HES. 9/
October 19, 2025 at 1:40 PM
There’s also increased awareness about endometriosis, which is great! And longer waiting lists to see the gynae service - I am hearing years in some trusts - which is not. But both of these will cause an increase in HES. 9/
So these would not show up in the gynae HES. And many of those gynae conditions are ones that you live with for years before getting to hospital. For endometriosis, it’s 8 on average. People being seen in hospital now, on average, first visited their GP about it before the pandemic. 8/
October 19, 2025 at 1:39 PM
So these would not show up in the gynae HES. And many of those gynae conditions are ones that you live with for years before getting to hospital. For endometriosis, it’s 8 on average. People being seen in hospital now, on average, first visited their GP about it before the pandemic. 8/
Acute COVID outside of pregnancy can cause temporary changes to menstrual cycles, but these rapidly resolve. 7/
pubmed.ncbi.nlm.nih.gov/37562052/
pubmed.ncbi.nlm.nih.gov/37562052/
Associations Among Menstrual Cycle Length, Coronavirus Disease 2019 (COVID-19), and Vaccination - PubMed
Experiencing COVID-19 is associated with a small change in cycle length similar to COVID-19 vaccination. These changes resolve quickly within the next cycle.
pubmed.ncbi.nlm.nih.gov
October 19, 2025 at 1:37 PM
Acute COVID outside of pregnancy can cause temporary changes to menstrual cycles, but these rapidly resolve. 7/
pubmed.ncbi.nlm.nih.gov/37562052/
pubmed.ncbi.nlm.nih.gov/37562052/
Similarly, there have been a string of dreadful outcomes in labour recently and a number of maternity services are currently under investigation. My colleagues say that are practicing much more defensively in this climate, and this may well be playing into HES numbers. 6/
www.gov.uk/government/n...
www.gov.uk/government/n...
14 NHS trusts the focus of national maternity investigation
Government announces 14 hospital trusts to be looked at in a national investigation.
www.gov.uk
October 19, 2025 at 1:35 PM
Similarly, there have been a string of dreadful outcomes in labour recently and a number of maternity services are currently under investigation. My colleagues say that are practicing much more defensively in this climate, and this may well be playing into HES numbers. 6/
www.gov.uk/government/n...
www.gov.uk/government/n...
The investigation into this came out in 2020. The guidance hadn’t yet been updated, but understandably people are being much more cautious about referring and admitting, which may well be causing that increase. 5/
www.hssib.org.uk/patient-safe...
www.hssib.org.uk/patient-safe...
The diagnosis of ectopic pregnancy
An estimated 12,000 women experience an ectopic pregnancy each year in the UK. Ectopic pregnancy occurs when the fertilised egg implants outside the uterus, usually in the Fallopian tube. If it’s left...
www.hssib.org.uk
October 19, 2025 at 1:30 PM
The investigation into this came out in 2020. The guidance hadn’t yet been updated, but understandably people are being much more cautious about referring and admitting, which may well be causing that increase. 5/
www.hssib.org.uk/patient-safe...
www.hssib.org.uk/patient-safe...