Korean J Obstet Gynecol.  1999 Dec;42(12):2666-2668.

Diagnosis and position shift of the first and second fetus in twin pregnancy

• Cho JY
• Jun HS
• Lee SH

Abstract

Correct discrimination of the first and the second twin is important. Case: (1) The first fetus, whose amnionic cavity was closest to the cervix at 19 weeks, even though its body was higher than the second fetus, was found to be closer to the cervix by 23 gestational weeks than its twin. (2) The result of the chromosomal study of dichorionic twins at 17 gestational weeks was male with 9 inversion of the presumed first, and female with trisomy 21 of the presumed second. AT 19 gestational weeks, the sex and order of the two were found to be reversed at sonography for selective termination. In diamnionic twins, the fetus in the amnionic sac closest to the cervix is nominated as the first.

Keyword

Twin; Determination of the Position

MeSH Terms

Amnion
Cervix Uteri
Diagnosis*
Discrimination (Psychology)
Down Syndrome
Female
Fetus*
Humans
Male
Pregnancy, Twin*
Twins*