Covid vaccines and fertility, pregnancy and breastfeeding

I’ve had a few enquiries about whether you can/should be vaccinated against Covid if you are planning to be pregnant/are pregnant/are breastfeeding, and also heard of some wrong information being bandied around, so here’s a short explainer of where things stand currently. References are hyperlinked if you would like more information on any of the topics.

Are pregnant and breastfeeding women excluded from vaccination?

There’s a lot of confusion around this, because initially, they were. This is because the Covid vaccines have not been tested in pregnant or breastfeeding women during the clinical trials. It’s standard practice to exclude pregnant and breastfeeding women from clinical trials — and as a result, there is no definitive evidence to show the vaccines are safe in these groups. However, neither is there any evidence to suggest they are unsafe — it just hasn’t been studied at all.

Upon further consideration, the decision to exclude pregnant and breastfeeding women from vaccination was changed at the end of last year. Breastfeeding women can now be vaccinated. Pregnant women can also be vaccinated if they are at high risk of exposure to Covid infection, or if they have underlying conditions that put them at very high risk of serious complications of COVID-19. Of course, most pregnant women who are currently eligible for vaccination do meet these criteria, simply by virtue of being a member of one of the priority groups for vaccination. Unfortunately, however, the change in guidance occurred on 30 December 2020, over the Christmas period and in amongst the furore about the new variant being discovered in the UK — so a lot of people, including healthcare professionals, missed it.

Can the Covid vaccines affect fertility?

There are rumours going round about this, but there is no evidence — either theoretical or real-world — to suggest that being vaccinated against Covid would negatively affect either male or female fertility (more details here and here). So if you’re planning to expand your family, go ahead and get vaccinated! And good luck with making that baby 😊

Should I get vaccinated if I’m pregnant?

Vaccination is always a personal decision, and any pregnant woman who is offered vaccination will have to weigh up the risks of being vaccinated with an untested vaccine versus the risks of contracting Covid during pregnancy, to them as an individual and to their baby. Every person’s circumstances is different, and every person’s perceptions of risks and benefits is different — so there isn’t a blanket answer to this question. If you’re pregnant and have been offered the vaccine, the best thing to do is to read up on the current available evidence, discuss with your healthcare team and family, and come to the decision that feels right for you.

It’s worth noting that vaccination in pregnancy isn’t inherently a risky thing to do — indeed, being vaccinated against flu and whooping cough is standard in pregnancy. There are some vaccines that cannot be given in pregnancy as they contain live replicating virus (MMR is an example), but the Covid vaccines don’t fall into this group: they neither contain live coronavirus nor any additional ingredients that are harmful to pregnant women or their babies. There is no known risk as to why Covid vaccines would be unsafe in pregnancy, and experimental studies looking at the effects of Covid vaccines on animals’ reproductive systems have not thrown up any concerns. Moreover, as more pregnant women across the world are vaccinated, reassuring evidence is accumulating that Covid vaccination of pregnant women does not result in increased risk of miscarriage or other complications.

Nonetheless, the vaccines haven’t been specifically tested in pregnant women, and they’ve only been being rolled out for a short time (certainly not the nine months it takes to produce a baby!) so you need to weigh up the unknown risks of vaccination versus the known risks of Covid infection in pregnancy, and make a decision that best suits your own circumstances and feelings. The Royal College of Obstetricians and Gynaecology (RCOG) have put together a great info leaflet to help guide your decision, and Dr Viki Male, an immunologist specializing in pregnancy at Imperial College, has written a fantastic explainer which she updates regularly with the latest evidence.

Note that if you do decide to get vaccinated while pregnant, some vaccinator training programmes have still not been updated to reflect the new guidance that pregnant women at high risk can be vaccinated — so you might be told you can’t make an appointment. This is incorrect — so you might want to make sure you have the latest RCOG guidance/Green Book references to hand when you make your booking so you can argue your case (tiresome but true).

Should I get vaccinated if I’m breastfeeding?

Again, the vaccines haven’t been specifically tested in breastfeeding women. However, there is no biological mechanism through which contents of the vaccine could get into breastmilk. Given the many health benefits of breastfeeding for both child and mother, and that there is no known risk associated with giving non-live vaccines whilst breastfeeding, UK guidance is that breastfeeding women can be offered Covid vaccines. The Breastfeeding Network has a good webpage that gets regularly updated with the emerging evidence around breastfeeding and Covid, including vaccines, which is a good port of call for more information.

In fact, it could be that getting vaccinated may confer immunity to your child through antibodies in the milk. The evidence around this is still being generated, but a study published this week described how six breastfeeding women who were vaccinated against Covid all ended up with anti-Covid antibodies in their breastmilk. That doesn’t yet prove that this will happen for all women, or that the amount of antibodies in the milk would be sufficient to protect a child from Covid infection, but it’s an encouraging sign. Research is ongoing into this so watch this space!

Ultimately, as with all things Covid, the evidence around this is accumulating, and guidance will likely change as we go along — not easy when you want hard and fast answers, but then I guess parenting is one of those areas where hard and fast answers are often elusive! I wish you well in making your choices.

I’m an infectious disease epidemiologist with special interest in zoonoses, new & emerging infectious, One Health, and interdisciplinary public health research