The correlation between follicular measurements, oocyte morphology, and fertilization rates in an in vitro fertilization program.
OBJECTIVE
To explore the relationship between follicle size and the morphology of the oocyte-cumulus-corona complex with fertilization rates in stimulated cycles of IVF.


METHODS
Retrospective comparison of measurements and observations of 2,429 oocytes from 215 patients undergoing 324 stimulated IVF cycles.


METHODS
A large hospital-based IVF program.


METHODS
Individual follicles were measured by ultrasound before transvaginal aspiration and the size was recorded. The oocyte-cumulus-corona complex from each follicle was examined and classified. The oocytes were checked for evidence of fertilization 17 to 22 hours after insemination.


RESULTS
The fertilization rate of all oocytes regardless of morphological type revealed a positive linear correlation with increasing follicle diameter. The fertilization rates of type I oocytes was marginally higher than type II oocytes, controlling for follicle diameter; however, this difference did not achieve statistical significance. Oocytes from follicles with a mean diameter > or = 16 mm had significantly higher fertilization rates than did oocytes from follicles with a mean diameter < or = 14 mm.


CONCLUSIONS
Follicle size is a better predictor of fertilization than is morphological characterization of the oocyte-cumulus-corona complex in IVF.
Dubey
A K
AK
New England Memorial Fertility Center, Stoneham, Massachusetts, USA.
Wang
H A
HA
Duffy
P
P
Penzias
A S
AS
D005260:Female; D005306:Fertilization; D005307:Fertilization in Vitro; D006801:Humans; D009865:Oocytes / Q000145:classification / Q000473:pathology* / Q000502:physiology; D006080:Ovarian Follicle / Q000000981:diagnostic imaging* / Q000473:pathology; D011247:Pregnancy; D012189:Retrospective Studies; D014463:Ultrasonography