Abstract
Purpose: To identify a subgroup of twin-prone women undergoing in vitro fertilization (IVF)
with blastocyst transfer. Materials and methods of investigation: In a retrospective cohort study, 2539 IVF cycles (1334 classical IVF and 1205 intracytoplasmic
sperm injection [ICSI] cycles) in 1641 couples in the 3-year period were included.
The cycles resulting in blastocysts were analysed in terms of female age, number of
IVF attempts, infertility indication, number of developed blastocysts, and pregnancy,
twin pregnancy and abortion rates. Results: Blastocysts developed in 52 % of cycles. The pregnancy rate per blastocyst transfer
was 43 % and the twin rate per pregnancy 20 %. We found a negative correlation between
twin pregnancy rates, female age and number of IVF attempts, and a positive correlation
between twin pregnancy rates and number of developed blastocysts. ICSI compromised
blastocyst development without directly affecting pregnancy and twin pregnancy rates.
Significantly higher twin pregnancy rates (39 % per pregnancy) were observed in women
younger than 34 years who had 3 or more developed blastocysts. Discussion, conclusions: The subgroup of twin-prone women undergoing blastocyst transfer is characterized
by age < 34 years, and number of developed blastocysts ≥ 3. Elective single blastocyst
transfer in these selected women would hypothetically reduce twin pregnancy rates
from 20 to 8 % per pregnancy.
Zusammenfassung
Fragestellung: Ziel war es, jene Untergruppe von Frauen auszumachen, die nach In-vitro-Fertilisation
(IVF) mit Blastozysten-Transfer zu Zwillingsschwangerschaften neigt. Material/Methoden: In einer retrospektiven Kohortenstudie wurden 2539 IVF-Zyklen (1334 klassische IVF-Verfahren
und 1205 Zyklen nach intrazytoplasmatischer Spermien-Injektion [ICSI]) in 1641 Paaren
über einen Zeitraum von 3 Jahren analysiert. Die Zyklen, die zur Entstehung einer
Blastozyste führten, wurden untersucht im Hinblick auf das Alter der Frau, die Anzahl
der IVF-Versuche, die Unfruchtbarkeitsindikation, die Anzahl der sich entwickelnden
Blastozysten sowie die Schwangerschafts-, Zwillingsschwangerschafts- und Fehlgeburtsraten.
Ergebnisse: In 52 % aller Zyklen entwickelten sich Blastozysten. Die Schwangerschaftsrate pro
Blastozysten-Transfer war 43 % und die Zwillingsschwangerschaftsrate pro Schwangerschaft
betrug 20 %. Zwillingsschwangerschaftsrate, Alter der Frau und Anzahl der IVF-Versuche
waren negativ korreliert, während es eine positive Korrelation zwischen Zwillingsschwangerschaftsrate
und die Anzahl der entwickelten Blastozysten gab. ICSI beeinträchtigte die Entwicklung
von Blastozysten, ohne dass sich dies direkt auf die Schwangerschafts- und Zwillingsschwangerschaftsraten
auswirkte. Wir fanden signifikant höhere Zwillingsschwangerschaftsraten (39 % pro
Schwangerschaft) bei denjenigen Frauen, die jünger als 34 Jahre waren und 3 oder mehr
entwickelte Blastozysten hatten. Schlussfolgerung: Die Untergruppe von Frauen, die nach Blastozysten-Transfer zu Zwillingsschwangerschaften
neigt, zeichnet sich durch ein jüngeres Alter < 34 Jahren und die Anzahl von ≥ 3 entwickelten
Blastozysten aus. Der Transfer einer einzigen Blastozyste in dieser ausgewählten Gruppe
von Frauen könnte theoretisch die Zwillingsschwangerschaftsrate von 20 auf 8 % pro
Schwangerschaft senken.
Key words
blastocyst - blastocyst transfer - in vitro fertilization - twin pregnancy
Schlüsselwörter
Blastozyst - Blastozysten‐Transfer - Zwillingsschwangerschaft - In‐vitro‐Fertilisation
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MD, MSc Sara Korošec
Department of Obstetrics and Gynecology University Medical Centre Ljubljana
Šlajmerjeva 3
SI-1000 Ljubljana
Slovenia
Email: sara_korosec@hotmail.com