Finally, the wait was over
On April 26, 2017, my husband Brian and I walked into my OBGYN office for the first ultrasound of our second pregnancy. To say that we were nervous is an understatement since our first pregnancy ended in a miscarriage in 2014. The first nine weeks of this second pregnancy seemed to last forever as we anxiously awaited the first ultrasound. We sat in the waiting room apprehensively wondering what the ultrasound screen would show and praying for the best.
“Well guys, it looks like you’re having twins!”
At last, it was our turn. We were escorted into the ultrasound room and I laid back on the chair with Brian sitting on my left. The ultrasound technician asked me how far along I was and said she would attempt to do an over-the-belly ultrasound first. “Let’s see what we can see,” she said.
She put the jelly on my belly and within seconds the ultrasound screen came to life. Before I could make any sense of what I was seeing on the screen she said, “Well guys, it looks like you’re having twins!” and quickly pointed to the two little babies on the screen.
Brian and I were completely shocked! Before we had a chance to process this unexpected turn of events, the technician explained that she would need to finish the ultrasound vaginally to get a better view and asked me to go give a urine sample while she adjusted her equipment.
So, within seconds of hearing the earth shattering news that we’re expecting twins we were separated. My mind was reeling with feelings of disbelief and excitement and Brian, who was left waiting back in the ultrasound room, was feeling the same way and later told me that he nearly passed out when the technician said that we’re having twins.
When I returned from the restroom, we continued the ultrasound. Much to our relief, the size and heart rates of our tiny babies were within a healthy range.
After the checking the size and heart rates of the babies, the technician started trying to determine what type of twins we’re having.
Until this pregnancy, I thought there were only two ways to categorize twins, identical and fraternal. But the technician explained that she needed to determine if our twins are mono/mono, mono/di, or di/di twins. Here’s a breakdown of what those three types mean:
Monoamniotic, monochorionic (mono/mono): These twins share the same placenta and the same amniotic sac.
- Mono/mono twins pose the highest risk because not only are they sharing nutrients by having the same placenta, but they could also become tangled up since nothing separates them from each other in their shared amniotic sac.
Monochorionic, diamniotic (mono/di): These twins share the same placenta but have their own amniotic sac.
- The main risk with mono/di twins is one baby hogging all of the nutrients since they share one placenta. However, on the positive side, they are separated by a membrane since they have their own amniotic sacs which prevents them from becoming entangled.
Diamniotic, dichorionic (di/di): These twins have their own placenta and their own amniotic sac.
- Di/di twins pose the lowest risk since they have their own placenta (source of nutrition) and their own amniotic sacs keeping them separated and tangle-free.
The technician was able to verify that our twins are mono/di twins — they’re sharing a placenta but she was able to detect a membrane separating them into two amniotic sacs.
So, what does it mean for us that we’re having mono/di twins? We have to monitor the babies closely to make sure that they’re growing at a healthy and equal rate. Hence, why I’m currently having an ultrasound every two weeks. So far, so good! They’re both doing great!
So, what’s the difference between identical and fraternal twins?
Identical twins start off the same way as a singleton baby, with one egg and one sperm. But then the zygote (fertilized egg) divides creating two separate and identical zygotes. The timing of this zygote division determines if the twins are mono/mono (division happens 8+ days after conception), mono/di (division happens 4-7 days after conception), or di/di (division happens within 3 days of conception).
Did you know that 1/3 of all twin pairs are identical?
Since identical twins share 100% of their genes, they are always the same gender and share the same basic features like hair color and eye color.
Fraternal twins are the result of the mother producing two eggs instead of one in her cycle, with each egg being fertilized by a separate sperm. These two little eggs travel their own journeys through the fallopian tubes and embed into the lining of the uterus separately. Fraternal twins always have separate placentas and amniotic sacs, but if they embed close to each other their placentas can fuse together.
Did you know that 2/3 of all twin pairs are fraternal? Half of these are boy/girl pairs, 1/4 are girl/girl, and 1/4 are boy/boy.
At my 19-week ultrasound, we discovered that our twins are identical which was an exciting surprise! More on that later when I make a post about our gender reveal.
I’d love to hear your ultrasound stories! Share them in the comments below!