Hum. Reprod. Advance Access originally published online on April 13, 2006
Human Reproduction 2006 21(7):1912-1917; doi:10.1093/humrep/del048
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Risks of miscarriage and early preterm birth in trichorionic triplet pregnancies with embryo reduction versus expectant management: new data and systematic review
Harris Birthright Research Centre for Fetal Medicine, Kings College Hospital Medical School, London, UK
1 To whom correspondence should be addressed at: Harris Birthright Research Centre for Fetal Medicine, Kings College Hospital Medical School, Denmark Hill, London SE5 8RX, UK. E-mail: kypros{at}technocom.com
BACKGROUND: Triplet pregnancies are associated with a high risk of miscarriage and early preterm birth. It is uncertain if the outcome is improved by embryo reduction (ER). METHODS: We examined trichorionic triplet pregnancies with three live fetuses at 1014 weeks of gestation that were managed expectantly or by ER. The two groups were compared for the rates of miscarriage, defined as pregnancy loss before 24 weeks, and preterm delivery prior to 32 weeks. In addition, systematic searches were performed to identify studies comparing outcomes in expectant management versus ER in triplet pregnancies. RESULTS: We combined data from 365 pregnancies managed in our centre with those of five previous studies. In total there were 893 pregnancies. In the ER group (n = 482) compared to the expectantly managed group (n = 411), the rate of miscarriage was higher [8.1 versus 4.4%; relative risk (RR) = 1.83, 95% confidence interval (CI) = 1.083.16, P = 0.036] and the rate of early preterm delivery was lower (10.4 versus 26.7%, RR = 0.37, 95% CI = 0.270.51, P < 0.0001). It was calculated that seven (95% CI = 59) reductions needed to be performed to prevent one early preterm delivery, while the number of reductions that would cause one miscarriage was 26 (95% CI = 14193). CONCLUSIONS: In trichorionic triplets, ER to twins is associated with an increase in the risk of subsequent miscarriage and decrease in risk of early preterm birth.
Key words: embryo reduction/first trimester/nuchal translucency/systematic review/trichorionic triplet pregnancy