2006-12-10 00:06:29 · 8 answers · asked by zizou 2 in Pregnancy & Parenting ➔ Pregnancy
Identical twins come from one egg that divides. During the first trimester, fetuses develop at roughly the same pace which is why the first ultrasound to 'date' the pregnancy is considered fairly reliable.
I would say a marginal error in measuring the 'crown to rump' lengths of one of the twins would result in a slightly different gestational age during the first trimester.
After the first trimester, fetuses develop at their own individual pace which is why twins are rarely born at identical weights, sometimes differing by a whole pound or two.
2006-12-10 00:32:54 · answer #1 · answered by Anonymous · 1⤊ 0⤋
An egg could have dropped later and a second child implanted after the first did. That is how women can carry 2 different raced babies at the same time. If you are sure they are identical, one could be getting better circulation and nourishment. I know several sets of twins and even as adults they aren't the same height. In the womb, age is determined by measurement. If they measure small or differently, the dates could be off. I knew a woman that had twins but one died in utero. So they let her go 2 weeks longer than when the baby should have come out. They measured her as a single and not as a twin. The baby came out 10 pounds,with long fingernails and hair that touched her shoulders. Measurements aren't foolproof, its just what doctors use to guess with.
2006-12-10 00:14:17 · answer #2 · answered by Velken 7 · 0⤊ 0⤋
There is only ONE egg that splits with identical twins.
If gestational ages are showing different, I'd be wondering if it was twin to twin transfusion.
This is when one twin takes more nutrients from the other.
2006-12-10 00:37:34 · answer #3 · answered by amanacer99 2 · 0⤊ 0⤋
could it be that they aren't identical but fraternal twins? This would mean that they had different implantation times as opposed to relatively the sames ones, which would cause the difference in gestational time.
2006-12-10 00:15:26 · answer #4 · answered by Anonymous · 0⤊ 0⤋
Maybe one twin is taking the majority of the nutrients and the other is developing more slowly because of it.
2006-12-10 00:08:51 · answer #5 · answered by tabby90 5 · 0⤊ 0⤋
same twins can not have diverse gestational sessions(hince "same"). yet there have been situations the position some fraternal twins were believed to have probably been conceived at diverse dates.
2016-11-30 09:34:36 · answer #6 · answered by ? 4 · 0⤊ 0⤋
One is getting more nutrients than the other.
2006-12-10 00:37:00 · answer #7 · answered by Ashley P 6 · 0⤊ 0⤋
one egg was fertilized befor the other one
could of had the egg relased on normal day then few days later another egg released then fertilizd by sperm still swimming around
2006-12-10 00:10:38 · answer #8 · answered by jokerswild 4 · 0⤊ 2⤋