Correlation Between Prenatal and Neonatal Birth Order in Twin Pregnancy

ABSTRACT

Little data is available correlating the in utero order of presentation and the birth order of twins. Our objective was to determine whether birth order in twin pregnancies corresponds to the order of presentation early in pregnancy. All twin pregnancies in which amniocentesis was performed from 1996 to 1998 were identified. Those with discordant genders that delivered at our hospital were included. Order of presentation was documented by ultrasound at the time of amniocentesis. Delivery data were obtained from review of medical records. Statistical comparison was done using two-tailed Fisher's exact test, Student's t-test, and Mann-Whitney U test. Sixty patients met inclusion criteria. Birth order corresponded to the order at the time of amniocentesis in 55 of 60 cases (91.7%). There was no difference in the rate of concordance of prenatal and neonatal birth order in twins delivered vaginally compared with those delivered abdominally (90.9 vs. 91.8%, p = 1.0). Cases with discordant prenatal and neonatal birth order had similar maternal ages, gestational ages at amniocentesis and delivery, and fetal presentation at delivery as cases with concordant birth orders. In dichorionic twin pregnancies, birth order is established early in gestation in >90% of cases regardless of route of delivery.

KEYWORD

Multiple gestation - ultrasound - birth order

REFERENCES

• 1 Finberg H J. Ultrasound evaluation in multiple gestation. In: Callen PW, ed. Ultrasonography in Obstetrics and Gynecology 3rd ed Philadelphia: WB Saunders 1994: 102-128
• 2 Bronshtein M, Bar-Hava I, Rafael Z B, Orvieto R, Ofir H, Istkovitz J. Twin gestation: is there a correlation between the location of the gestational sacs at the beginning of pregnancy, and the order of delivery?.  Eur J Obstet Gynecol Reprod Biol . 1998;  77 189-191
• 3 Evans M I, Goldberg J D, Horenstein J, Wapner R J, Ayoub M A, Stone J, Lipitz S, Achiron R, Holzgreve W, Brambati B, Johnson A, Johnson M P, Shalhoub A. Selective termination for structural, chromosomal, and mendelian anomalies: international experience.  Am J Obstet Gynecol . 1999;  181 893-897
• 4 Goedert J J, Duliege A M, Amos C I, Felton S, Biggar R J. High risk of HIV-1 infection for first-born twins: the international registry of HIV-exposed twins.  Lancet . 1991;  338 1471-1475
• 5 Grobman W A, Parilla B V. Positive predictive value of suspected growth aberration in twin gestations.  Am J Obstet Gynecol . 1999;  181 1139-1141
• 6 Cho J Y. Diagnosis and position shift between the first and second fetus in a diamniotic twin pregnancy.  Int J Gynecol Obstet . 1999;  66 41-42
• 7 Meagher S, Davison G. Early second-trimester determination of fetal gender by ultrasound.  Ultrasound Obstet Gynecol . 1996;  8 322-324