Vanishing twin syndrome Is it associated with adverse perinatal outcome

Capsule:
Pregnancies with vanishing twin syndrome are associated with an adverse perinatal outcome, as compared with singletons and twins, even after controlling for confounders such as fertility treatment and maternal age.

Authors:
Evyatar Evron, B.Sc., Eyal Sheiner, M.D., Ph.D., Michael Friger, Ph.D., Ruslan Sergienko, B.Sc., Avi Harlev, M.D

Volume 103, Issue 5, Pages 1209-1214

Abstract:

Objective:
To evaluate whether vanishing twin syndrome (VTS) is associated with adverse perinatal outcome.

Design:
A retrospective cohort study investigating the impact of VTS on perinatal outcome was conducted. Parturients were classified into three groups: those pregnancies that started with double fetal sacs and spontaneously reduced into one (VTS), those with dichorionic twins, and those with singleton pregnancies. Statistical analysis included multiple logistic regression models to control for possible confounders.

Setting:
Tertiary university medical center.

Patient(s):
The study involved 252,994 singleton deliveries between the years 1988 and 2012.

Intervention(s):
None.

Main Outcome Measure(s):
The impact of VTS on perinatal outcome.

Result(s):
During the study period, 278 pregnancies with VTS were compared with 1,801 pregnancies of dichorionic twins and 252,994 pregnancies of singletons. A significant linear association was documented among the three groups and various adverse outcomes, including gestational diabetes mellitus (GDM), intrauterine growth restriction (IUGR), very low birth weight (VLBW), and perinatal mortality. The higher risk was noted in the VTS group, and the lowest in singletons. Using multivariable logistic regression models, while controlling for confounders such as fertility treatment and maternal age, VTS (as compared with singletons) was found to be an independent risk factor for several adverse perinatal outcomes including GDM, IUGR, VLBW, low Apgar scores, and perinatal mortality (adjusted odds ratios with their respective 95% confidence intervals, 1.4 [1.01–2.0], 2.7 [1.7–4.3], 6.9 [4.7–10.2], 1.9 [1.1–3.3], 2.4 [1.2–4.5]).

Conclusion(s):
Pregnancies with VTS are associated with an adverse perinatal outcome, even after controlling for confounders such as fertility treatment and maternal age.

  • Shvetha Zarek

    Thank you for an interesting study that highlights pathology related to VTS. This is of great interest to many investigators! This study provides ample data on the risks associated with VTS, and much of the results (Tables 1-3) are descriptive (with statistical testing employed). Have the authors considered evaluating specific neonatal and maternal outcomes in regression modeling with VTS as the exposure compared to singleton pregnancies and twin pregnancies as referents with adjustment for the other characteristics noted in Table 4 (and 1) as covariates? This may provide a clearer answer to the research question at hand. Any comments from the authors are welcome!

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