Yes, you read that right. Twins (non-identical) can be born at completely different times, sometimes even years apart. Let me tell you more.
The older Penny is getting, the more comments on how alike she is to Brae, her big bro who was born in January 2019, a whole 27 months before her we are getting. That in itself is not unusual I guess as siblings often look alike and let's be honest, a lot of the time, all babies look the same anyway. But there's a more science-y reason why they look the same.
When we had IVF, they managed to extract a decent number of eggs - well in the 30's, which is great and with a condition like Polycystic Ovary Syndrome. The main issue with PCOS is that the woman has her eggs, her body just doesn't get the hang of releasing them when it 'should' so the good part is that on extraction day, they can take a lot of eggs, mix them with the sperm and watch closely to see how many form embryos. If (fingers crossed) embryos form, they're then closely monitored and graded to evaluate which looks the strongest and would have the best chance of developing into a foetus as would happen in any 'normal' pregnancy. This is what happened for our cycle of IVF and they managed to get 11 good embryos (which in IVF world is a LOT!) The embryo with the best grading (sounds so weird doesn't it?) was then chosen and voila, 40 ish weeks later Brae was here. What about the other 10 you say? Well, we chose to freeze them. We didn't think we'd have any other babies as it had been long road to get to this far and we genuinely felt really lucky that it had worked 1st time but there are other reasons for freezing them such as donating them to research or to others who need them so in the freezer they went.
A global pandemic later and many chats led to us giving IVF a go to see if we could give Brae a brother or sister. The whole process was much simpler as there was none of the injecting, blood tests and every other day hospital visits. It was a matter of some drugs a couple of weeks before that help prepare the womb for implantation then a quick appointment to put the embryo in and then wait until the much anticipated pregnancy test 11 days later.
Obviously for us it worked and Penny arrived in April 2021, 2 years and 3 months after Brae BUT technically they were 'made' at exactly the same time, she'd just been chilling the freezer whilst Brae was implanted straight away. This makes them Fraternal twins which explains why they are so alike. Identical twins occur when the egg splits into two but non-identical twins occur when there are two separate eggs hence a lot of IVF babies taken from the same harvest or cycle are twins but born years apart.
There you go, science lesson of the day over and a little bit more light shed on the amazing world of IVF. Any questions, ping them over. I'd be happy to answer and share any of our story, especially if it helps someone else.