A mother has revealed how she got pregnant while she was already pregnant – conceiving her two daughters five days apart.

Odalis and Antonio Martinez, of San Pablo, California , were overjoyed when they found out they were expecting a baby in November 2020, after being left heartbroken by a miscarriage a few months previously.

But the best was yet to come when the 25-year-old discovered during her first scan that she was actually expecting two babies – conceived at different times during the same week.

The incredibly rare phenomenon is known as superfetation and is when a second, new pregnancy occurs during an initial pregnancy – and can occur days or weeks after the first one.

The full-time-mother said it felt like a ‘miracle’ to have daughters Lilo and Imelda Martinez-Atoyac arrive but admits that the pair look so similar that her and Antonio have mistaken them for one another.

In fact, the duo look so alike that Odalis says she tells people they are twins rather than having to explain the truth.

Odalis said: ‘I got pregnant while I was already pregnant.

‘I just say that they’re twins but after reading a lot of articles I know that they’re technically not twins but it’s just confusing for people so I just tell them like “Yeah, they’re twins.”

‘They’re technically not even identical but everyone thinks that they are. They definitely look a lot alike.

‘Sometimes me and my husband, well more my husband, will get them mixed up with each other.

‘Antonio will have a baby for an hour and be like “Oh Lilo” this and that and I’m like “You have Imelda” and he will be say “What?” and I’m just there laughing because he was like “Oh my God for a whole hour I thought I had Lilo”.

‘I usually don’t get them mixed up anymore, just because I’m with them 24/7 so I feel like I can tell them apart pretty easily, but a lot of people get them mixed up.’

Odalis and Antonio, who currently works as a counsellor, married in early 2020 and dreamed of starting their own family.

She fell pregnant but discovered she had miscarried during their 12 week check-up in July 2020.

A few months later the couple decided to try again, and she fell pregnant that same month.

Odalis said: ‘I was extremely happy that the pregnancy test was positive and we were on our pregnancy journey again.

‘I felt really lucky. I know a lot of people that have been trying to conceive and just haven’t been able to so that was also a fear of mine, but thankfully that wasn’t our case and I fell pregnant really quickly.

‘I felt really really happy and also scared because of the miscarriage. It was pretty terrifying throughout my whole pregnancy not knowing if that was going to be the outcome again.

‘Hoping for the best but knowing there’s always a possibility that things might not go as planned.

‘The month that we conceived – and before we even knew that I was pregnant with two babies – Antonio and I had gone to the park to work out.

‘He was shooting basketballs and said “OK, if I shoot this basket and I make it, you have twins. Just kidding”.

‘And he made it and I was like, “Haha, very funny”.’

Odalis went into her first ultrasound alone because 31-year-old Antonio had to wait outside due to Covid regulations.

Odalis said: ‘I was just so scared that they were going to tell me, “Oh, there’s no heartbeat”, so I was so anxious the whole time I was texting Antonio: “I’m so scared”.

‘The doctor comes in and I’m trying to mentally prepare myself for anything and when she found the first baby and the heartbeat I was crying with so much happiness.

‘And then she started going back and forth and I was wondering why – my mind just went to the worst-case scenario because of the traumatic experience that we had.

‘That’s when she told me that she had found another baby that also had a heartbeat.

‘I was just crying with happiness. I felt like the first baby that we had lost was in the room with me and saying it was going to be ok.

‘When you go to the first ultrasound they check everything and around the day that you actually conceived the baby, and that’s when she told me that they were conceived five days apart, which I didn’t even know could happen.’

An exact date of conception can be determined by looking at the size of the fetus and comparing it to the same pattern of growth in other pregnancies.

Fetus grow quickly, which is how ultrasound can determine how old they are, and how a specialist could have told Imelda and Lilo were not conceived at the same time.

The mother-of-two said her due date was set in the middle – two days after one baby would have been 40 weeks and two days before the other one would have been 40 weeks.

The babies arrived on August 10 2021 and Lilo, who was conceived first was also born first weighing 6lbs 12oz. Imelda then followed, weighing 7lbs 3oz.

Odalis said: ‘I feel like it’s some sort of miracle that I experienced this double pregnancy. Because of our first experience, it made everything during this pregnancy feel so much more special and magical.

‘Just how easy I was able to conceive, and knowing that I had two babies, I just felt like there was so much light after such a dark place. It was the best surprise ever.

‘It was a really beautiful moment to finally be able to hold them in my arms.

‘When I held them and knew that they were ok, I can’t even explain the feeling. I love my family and my husband, but I had just never experienced a love and happiness like that.’