Updating to say that I did meet with my OB and she said nothing about the GD concern being because of the growth disparity. (The nurse or receptionist who called me with the info represented it incorrectly or had it mixed up, I think. "Everything looks great but there IS a difference in twin size, in that one twin is much bigger than the other, and the perinatologist wants you to be tested for gestational diabetes.") According to my OB, the issue was not the 25% difference. It is the fact that twin B has tracked consistently in the 97th percentile. She said big healthy twins are good, and that my babies show every sign of being healthy & happy (she had me in for a NST and took me off after ten minutes, I think, because their strip was "perfect") but that it IS unusual to see 97th percentile.
She also remarked that I'd passed the one hour test with no problems, but that it can be "false" for a twin pregnancy. She said if we ruled out GD as an issue, it might make invasive testing further down the road less likely to be recommended (i.e., amnio to test lung maturity at 37 weeks, since GD babies can have respiratory issues--but that all was predicated on the possibility of the recommendation to induce at 37 weeks, which I wouldn't be comfortable with, anyway....particularly because of the likelihood of respiratory distress!!! I think she thinks 37 week MZ twins withOUT GD are likely to have mature lungs because of the whole "twins are term earlier" rap.)
I neglected to ask her how the one-hour results would be false for a twin pregnancy....didn't ponder it until later. But, I already know that the 3-hour test is more accurate than the one-hour screen, and that the one-hour screen is supposedly just a simpler thing to rule out the majority of people who don't need further testing. Isn't the inaccuracy of the one-hour more in the realm of producing false positives? (i.e., people who fail it, but go on to pass the more accurate 3 hour test?) What is the likelihood that passing results would be FALSE for a twin pregnancy?
I should have asked.
Anyway, my whole approach in questioning her was sort of from the angle of "why suspect GD because one twin appeared to grow less?" And she put that one to rest right away.
The issue with the undiagnosed GD possibility was not the disparity, but the consistent size trend. (The fact remains that both twins have tracked above average, so we're supposedly dealing with two "big babies" even though one is consistently bigger than the other.)
I also started thinking what if the one-hour results were false and these babies ARE growing big because of GD, what would the impact be? (I do compare my "instinctive" diet with its natural aversions/tastes to the probable management diet for GDM, but I don't really know much specifically about that. And it's true that I eat a dish of ice cream with a banana almost every night before bed.... And in the last week before that ultrasound, I had eaten cookies in the middle of the day and a bunch of fruit leathers, when I was out and about and lunch plus an extra apple wasn't holding me.)
re: ice cream. It keeps me through the night and lets me get up feeling "normal" instead of shaky or nauseated, so I've stuck to the ice cream at night diet. I think it helped some with my weight gain (though it's only one dish a day, not like everything hinged on that
) since through the 2nd trimester I was eating mostly broccoli, bok choy, graprefruit, miso, brown rice, carrots/onions/peppers, eggs, apples, avocado and chicken. Closer to the 3rd trimester I added in pork. Not that all of those foods were "lean", but I'd say there weren't tons of calories in most of the things I was able to eat. So I think the ice cream helped.
Only once I was into the 3rd trimester could I seem to tolerate beef, and I started eating fish 2 or 3 times a week (haddock, cod, or salmon) then, too. That ice cream pretty much is the only time I have any dairy at this point, save a dollop of sour cream if I have a quesadilla (which also has cheese in it), or the very occasional grilled cheese (bread doesn't appeal to me very much.)
So, those have been my dietary instincts. No pancakes or French toast (wholegrain or not), I don't tolerate things like oatmeal or other cereal grains, bread, pasta (again, not even wholegrain), and I've been off milk/yogurt/most cheese since the 1st trimester. (For awhile, I ate lots of cheddar slices with apples, but now I just eat apples alone and cheese gives me an "off" feeling. No more nausea, just a bad aftertaste and an icky feeling overall.)
So the upshot is I consented to the three hour test. Which I took yesterday. And found out today that I passed.
I also had an NST, and twin A (the smaller one) wasn't as reactive on the strip as they'd like. Which nags at me a bit, but then, this was after the horrid GD test experience and I went to get some eggs when I finished (4+ hours after arriving at the lab) only to find out that they stopped serving breakfast at 10:15 and they only had things like bagels and breakfast pastries out. Ugh.
So instead of having my usual good protein meal and showing up for the NST, I was feeling icky from the test and from eating "off" for me. Hopefully that's all the NST results were about...
Well, another ramble.
Hopefully these test results put "Doctor Clouseau" and his comments to REST! Twins DO "grow big," and ultrasounds estimate size and can be wrong either way (my first child's late-term u/s measurements were off the other way, indicating a "nice small baby" even though my instincts told me she was 8 lbs + and I disbelieved the results but was relieved that they went "that way" because it was less likely I'd be pressured to induce, or pressured into a c-section for "failure to progress" even though my labor was long because of her positioning.... She was 8 lbs 12.5 oz when she was born, and I still remember my medwife's shock. She actually remarked quietly to the apprentice midwife, "Lucky I didn't know that baby was so big." Irked me so much, just the obvious implication.)