First-trimester embryo size discordance: a predictor of premature birth following multifetal pregnancy reduction.
OBJECTIVE
We have previously reported a correlation between the starting number of embryos for multifetal pregnancy reduction (MFPR) and discordance in size during the first trimester. Here we evaluated the correlation between the degree of discordance and length of gestation in the remaining fetuses.


METHODS
Observational clinical series.


METHODS
Academic medical center with a single physician who performs a large number of MFPRs.


METHODS
Analysis of 252 consecutive MFPRs from a 2.5-year period (1996-1998).


METHODS
MFPR for patients with multifetal pregnancies.


METHODS
We evaluated the correlation between the degree of discordance in embryo size, as measured by the greatest difference in crown-rump length (CRL) (delta max), and the length of gestation.


RESULTS
Embryo size discordance was related to length of gestation of the remaining fetuses after MFPR. Of 72 patients with a delta max >5 mm, the rate of severe premature birth (delivery at <28 weeks' gestation) was 9.7%, compared with 1.7% for patients with a delta max <5 mm (P<.01). Of patients with severe premature birth, 70% had delta max >5 mm, compared with less than 30% in patients who delivered after 28 weeks (P<.05).


CONCLUSIONS
Variations in embryo growth patterns in multifetal pregnancies may be observed even in the first trimester, which may be predictive of late pregnancy outcomes. With a delta max > or =5 mm, there is a significant increase in the risk of severe premature birth (delivery at <28 weeks).
Carreno
C A
CA
Department of Obstetrics and Gynecology, Center for Fetal Diagnosis and Therapy, Wayne State University, Detroit, Michigan, USA.
Yaron
Y
Y
Feldman
B
B
Treadwell
M
M
Ayoub
M A
MA
Evans
M I
MI
D018568:Crown-Rump Length; D004622:Embryo, Mammalian / Q000033:anatomy & histology*; D005260:Female; D005865:Gestational Age; D006801:Humans; D007752:Obstetric Labor, Premature / Q000175:diagnosis*; D011247:Pregnancy; D018607:Pregnancy Reduction, Multifetal; D011272:Pregnancy, Multiple