Different weights at 26 weeks

My mono-di boys started out being the exact same weight for quite a while, measuring right to the exact day of LMP. Then about a month ago, they were about an ounce different, about 12% apart. 2 weeks ago they were 3 oz apart, still about 12%. Today they measured 2.15 lbs and 1.75 lbs.. which is about an 18% difference. Their fluid is looking good and all their organs are the right size, and hearts and movements are good so the doctor is not concerned at all about TTTS. They are at about the 50th and 30th percentile for weight for gestational age for a single pregnancy.. so one is definitely a little smaller than I would like!

I am just curious.. how far apart were your mono-di twins in weight? Is it normal to have one that is so much smaller than the other? How common is measurement error?

 

I am not sure how common measurment error is, but I am *guessing* that the measurments can easily be misjudged?
My girls had a noticable difference as well and were delivered at 6lbs & 4lbs 10oz

 

My mono-di girls are about 30% apart or so. The little one has IUGR so we're monitoring it closely. We have no signs of TTTS here either! At our last growth scan they weighed 1 lb, 11 oz and 2 lbs 6 oz (at 27w5d).

 

My mono-di girls were the same weight initially but since about 24 weeks have been anywhere from 14-19.5% different. Their last scan they were 16%.

When we had the appt where they were 19.5% (really 20 but they didn't want to worry us too much), the MFM specialist wasn't too concerned because Baby A was big and Baby B was normal so they felt A was skewing the results. Because fluid, organs and HR's looked good, they felt perhaps their growth spurts were off a bit. The doctor also told us that there is a margin of error on the u/s's and at that time it was +/- 4 oz.

They brought us back 2 weeks later to double check and at that point B did catch up to A a bit and were 14% different. If they had continued to have higher discordance, they were going to start more frequent u/s's and biophysical profiles to monitor their health and signs of distress. Luckily that didn't happen so we went back to normal schedule.

Last week at my growth scan, they were 3lb 13 oz and 4 lb 9 oz so there is a difference but nothing that they are concerned about. My practice does not increase monitoring until they get to be 20% or greater difference.

 

My mono-di girls were born with a 24% size difference. I didn't have an ultrasound until 20 weeks. At that time they were measuring the same, then began to diverge. My bigger girl grew at a typical rate but my smaller one grew more slowly. When they reached 20% size difference the peri recommended increased monitoring. By 36 weeks they recommended that I deliver because my little one hadn't grown much in the last two weeks. After their birth we found out that my little one's cord had implated near the edge of the placenta and she wasn't getting as many nutrients as her sister.

All that said, they're both perfectly healthy 22 month olds now, with no signs that one was smaller than the other at birth.

 

Interesting to know they can be so different and still turn out healthy! My doctor said that he often sees twins diverge in growth, but they can never really explain why sometimes, so I was just curious how often it happens. I guess they're resilient little things! Make up for lost time when they get out

 

Could be a wrong measurement as well (don't know anything about the mono-di). Mine both measured 2lbs11oz at 26 weeks, which is above average, so your 2lbs15oz is way above average, which of course is possible but my experience is that a lot of twins are estimated larger than they are (at least more than the other way around). Mine measured 4lbs5oz and 4lbs6oz and lower 6lbs range at 30 and 34 weeks resp. They were born close to 8lbs so pretty accurate all along!