IVF雙胞胎若其中一胎死腹中，存活胎兒較易早產及體重較輕

Hum Reprod. 2017 Nov 1;32(11):2298-2304. doi: 10.1093/humrep/dex277.

Vanishing twin syndrome among ART singletons and pregnancy outcomes.

Magnus MC1,2,3, Ghaderi S1, Morken NH4,5, Magnus P6,7, Bente Romundstad L8,9, Skjærven R4,10, Wilcox AJ11, Eldevik Håberg S6.

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Abstract

STUDY QUESTION:

Among babies born by ART, do singleton survivors of a vanishing twin have lower birth weight than other singletons?

SUMMARY ANSWER:

Vanishing twin syndrome (VTS) was associated with lower birth weight among ART singletons; a sibship analysis indicated that the association was not confounded by maternal characteristics that remain stable between deliveries.

WHAT IS KNOWN ALREADY:

Previous studies indicate that ART singletons with VTS have increased risk of adverse pregnancy outcomes, compared with other ART singletons. The potential contribution of unmeasured maternal background characteristics has been unclear.

STUDY DESIGN, SIZE AND DURATION:

This was a Norwegian population-based registry study, including 17 368 mothers with 20 410 ART singleton deliveries between January 1984 and December 2013.

PARTICIPANTS/MATERIALS, SETTING, METHODS:

The study population included 17 291 ART singletons without VTS, 638 ART singletons with VTS and 2418 ART singletons with uncertain vanishing twin status. We estimated differences in birth weight and gestational age comparing ART singletons with VTS first to all ART singletons without VTS, and subsequently to their ART siblings without VTS, using random- and fixed-effects linear regression, respectively. The corresponding comparisons for the associations with preterm birth and small for gestational age (SGA) were conducted using random-and fixed-effects logistic regression. The sibling analysis of preterm birth included 587 discordant siblings, while the sibling analysis of SGA included 674 discordant siblings.

MAIN RESULTS AND THE ROLE OF CHANCE:

ART singletons with VTS had lower birth weight when compared to all ART singletons without VTS, with an adjusted mean difference (95% CI) of -116 g (-165, -67). When we compared ART singletons with VTS to their ART singletons sibling without VTS, the adjusted mean difference was -112 g (-209, -15). ART singletons with VTS also had increased risk of being born SGA, with an adjusted odds ratio (OR) (95% CI) of 1.48 (1.07, 2.03) compared to all ART singletons without VTS, and 2.79 (1.12, 6.91) in the sibship analyses. ART singletons with VTS were also more likely to be born preterm, although this difference did not reach statistical significance.