She understood antibodies would be passed on to the baby through the vaccine which would give the baby's immune system a head start against the virus.
Cavanagh already had her own confidence in vaccines, and her healthcare professionals advised her to get the Covid-19 vaccination.
Cavanagh also got vaccinated to protect her relative, who is unable to get the jab as he has just finished chemotherapy.
"It really hits home. You know there are people that can't be vaccinated ... but when it's somebody so personal to you, it really makes it a lot easier to make that decision.
"Being able to keep him safe and spend time with him and having a higher vaccinated population means that it's less likely he will contract something that he can't protect himself against."
Cavanagh said there was "a lot of the mahi" we can do for people who could not get vaccinated.
"That's really important. If you're on the fence there's a lot of people you're protecting beyond just yourself by choosing to get the vaccine.
"I want to have my family be able to come and meet my baby when they're little.
"I don't want it to be in lockdown. I don't want to miss out on sharing that really important part of my baby's life when they're so small with loved ones."
Tauranga Hospital antenatal clinical midwife co-ordinator Phoebe de Jong said the vaccine was "a real added bonus" for pregnant women and their babies.
"At the moment [we] aren't vaccinating our tamariki, so if we can provide the babies that little head start of some natural immunity to Covid-19, that's a real benefit for pregnant mums and their whānau."
De Jong said unvaccinated pregnant women who caught Covid could become "seriously unwell" and had an "increased risk" of hospitalisation, ventilation and requiring intensive care.
Another danger was an increased risk of giving birth prematurely.
"If they're having their babies early, then their babies will often need neo-natal intensive care unit support as well."
Concerns from expecting mothers were "often around the unknown".
"Now that Pfizer has been given around the world to hundreds of thousands of pregnant women, we know that it is really safe.
"Now that we have that information, we are encouraging all women to get vaccinated at any time - either considering pregnancy, in the first trimester, second trimester, any time in pregnancy."
This also included while breastfeeding.
De Jong said there had been no reports of long-term harm from having the vaccine, but there were "certainly" reports of long-term harm from getting Covid-19.
For women who were hesitant about the vaccine, it was important to reach out to a trusted healthcare professional, De Jong said.
"What's important is that women receive accurate up-to-date advice around the safety of the vaccine. But also have the time and the ability to discuss their fears or their barriers as to why they have not yet received a vaccination.
"Most of those barriers we can assist women in solving. If we can do that to improve the vaccination rate in our wāhine hapū then we would absolutely like to do that and work with women in that way."
New Zealand College of Midwives Bay of Plenty regional chair Kelly Pidgeon said "respectful and informative discussions" about the vaccine had led to women getting vaccinated.
"It is normal for pregnant women/parents to want to protect their babies and so of course women want to feel they are making the safest choices.
"Midwives have a professional role and responsibility to provide evidence-based information to pregnant women," she said.
"Excellent resources" from the Immunisation Advisory Centre and the Ministry of Health supported these discussions.
Whānau Āwhina Plunket chief nurse Dr Jane O'Malley said one of the best ways to protect young tamariki was to get them immunised against preventable diseases, including Covid-19.
O'Malley said Whānau Āwhina Plunket had received "a few queries" about getting the vaccine while pregnant or breastfeeding.
"The Ministry of Health advises if you're pregnant, you can get a Covid-19 vaccine at any stage of your pregnancy.
"If you're breastfeeding, there are no safety concerns about getting the Pfizer vaccine," she said.
"When you're vaccinated, this can also provide some protection against Covid-19 for your baby through your breastmilk."
Whānau Āwhina Plunket based their recommendations on advice from the Ministry of Health, which included that "all pregnant and breastfeeding women should have their Covid-19 vaccination".