Updated: May 27, 2021
After the shock and excitement of finding out we were expecting twins had settled, I decided to start doing some research on the types of twins we were carrying. The sonographer told me that they were sharing the same sac and placenta, which I had only known meant that they were genetically identical. I turned to Dr. Google and typed in "twins one sac one placenta" and down the rabbit hole I went...
These kinds of twins, also know as mono/mono or "momo" twins, occur when a fertilized egg splits very late, typically between 8-13 days after conception. This situation occurs in only 1% of all twin pregnancies. They are the second rarest twin type, the rarest being conjoined twins.
As I read on, I learned that identical (monochorionic) twin pregnancies have many serious risks associated with them, including Twin-to-Twin Transfusion Syndrome (TTTS), Twin Anemia Polycythemia Sequence (TAPS), Intrauterine Growth Restriction (IUGR), and in some rare cases, Vanishing Twin Syndrome. There was also a higher risk for chromosomal abnormalities, congenital defects, and cognitive issues. These risks apply to all identical twin types - both mono/mono and mono/di (monochorionic/diamniotic - meaning they share a placenta but have a separating membrane). In addition to these risks, however, mono/mono twins also have a high risk of fetal demise due to cord entanglement/compression from sharing the same space. As these babies move around, their cords can wrap, twist, and knot, cutting off their vital lifelines. Up until viability (24 weeks gestation), the chance of the pregnancy surviving is 50 percent. If this pregnancy makes it to viability, it is recommended that the mother be admitted to the hospital for frequent monitoring until the babies are delivered. The optimal time for mono/mono twins to be delivered is between 32-34 weeks, as the risks of being in the womb are larger than being out.
My heart dropped into the pit of my stomach. Tears welled up in my eyes. I could feel my chest tightening and a deep burning in my throat. I shut my laptop and flew into the living room where Brian was sitting on the floor playing with Silas. "What's wrong?" he asked. I burst into tears. I could barely breathe, let alone speak. When I finally (somewhat) collected myself, I explained to him everything that I had read.
I was scared. I was devastated. "Best case scenario, I have to leave Silas for potentially 10 weeks and then the twins will have to be in NICU?!" I sobbed. It just didn't seem fair. Brian being a patient, calm, and level-headed guy (that I am lucky enough to have married) reminded me that we hadn't even had our consult with the Maternal Fetal Medicine (MFM) doctor yet, and that I shouldn't worry until I had my more detailed scan. He pulled me into his warm embrace and told me that everything was going to be okay.
I did feel a little better after talking to him, but I wasn't ready to be done crying - so I called my mom. She was working, but picked up the phone because it's unusual for me to call, especially during the day. I cried at her and told her everything I had just told Brian. She let me get everything off my chest and sat quietly on the phone until I was done. "So, these are things that can happen, not things that are happening, correct?" she asked. I paused and took a breath. I knew what she was saying. She was reminding me that worry is wasteful. That there is no sense in getting worked up about something that hasn't even happened yet. "Please stop Googling and wait to talk to the specialist," she said sternly. She has never been a big fan of my need to know everything. Due to having a background in science and math, I have a passion for research. Once I get interested in a topic I try to absorb as much information as I can.
Because I didn't want to share the "doom and gloom" of this pregnancy with a lot of people, I was feeling very isolated after reading all these harsh statistics. I decided for my own sanity that I would stop doing research with Dr. Google and instead look for support groups online. I found one on Facebook, called MoMo Twins Support and there were so many wonderful stories with plenty of positive outcomes. There were also a lot of heartbreaking posts, but I knew that I was in the right place, no matter what my outcome would end up being. This group of mamas (and some dads too!) had either already been down my path of the unknown or were just beginning it like me. They understood how scary and isolating this pregnancy can feel. They were so knowledgeable on the subject of momos and SO incredibly supportive. I initially posted on the page to introduce myself around 10 weeks. I explained to the group that I was told by my OB practice that the babies were sharing the same sac/placenta. A lot of women commented that I shouldn't be discourage until I meet with MFM, and that because only 1% of twin pregnancies are mono/mono, there was a really good chance that they'd find a membrane. If a membrane was found, I would be carrying mono/di twins.
I felt at home right away and have continued to use the page as a resource through my entire pregnancy. Whether I've wanted to explain how scared I was feeling, had questions, or wanted to share a pregnancy milestone, the mamas in this group were always there to cheer me on or offer support! If you're an expecting momo mama, I HIGHLY recommend you join this group.
The Maternal Fetal Medicine Consult
Two weeks later when I was 12 weeks + 2 days along, we had our first consult with MFM. I was so nervous I was visibly shaking. My always-perfect blood pressure reading was exceptionally high. My heart felt like it was beating out of my chest. I just wanted to hear 2 little heartbeats The rest of the news I could handle, no matter what it may be. I laid down on the bed and Brian grabbed my hand (thankfully, you could have a support person with you at MFM appointments). The mask I was wearing felt like it was suffocating me.
"Here's Baby A's heartbeat.... and here's Baby B's," the sonographer said, sounding a little relieved herself. I let out a long sigh. The ultrasound was pretty standard. They did a growth scan as well as a Nuchal Translucency, or NT scan, which means they measure the pocket of fluid behind the fetus' neck as an initial marker for chromosomal abnormalities. The sonographer finished up and directed us to another room to talk to the doctor. We sat there for a few minutes, and I could feel that familiar anxiety creeping back up on me as we waited for her to come in.
The doctor came in and sat down. She introduced herself and gave a little background about her experience as an MFM doctor. Her demeanor was calm, and she was very charismatic. I think she could see the apprehension on my face. She cut the small talk and turned the conversation towards the pregnancy.
"Cassidy, you are carrying a very rare set of twins."