Multifetal pregnancy reductions of triplets to twins: comparison with nonreduced triplets and twins.
OBJECTIVE
Multifetal pregnancy reduction has been shown to improve survival rates in high-order multifetal pregnancies (>/=4). There is, however, some controversy as to whether multifetal pregnancy reduction improves pregnancy outcomes of triplets reduced to twins. The purpose of this study was to evaluate this issue by comparing outcomes of triplet gestations undergoing reduction to twins with outcomes of nonreduced twin gestations and expectantly managed triplet gestations.


METHODS
The study included 143 triplet pregnancies that underwent reduction to twins over a 10-year period at a single center. These were compared with 12 nonreduced triplet pregnancies from the Wayne State University Perinatal Database and with 2 groups of twin pregnancies: 605 from the Wayne State University Perinatal Database and 207 from the Quest Diagnostics Database.


RESULTS
The miscarriage rate for expectantly managed triplets was 25%, compared with 6.2% for triplets reduced to twins. This rate was similar to the rates for both groups of nonreduced twins: 5.8% (Quest) and 6.3% (Wayne State University). Severe prematurity occurred in 25% of nonreduced triplets compared with 4. 9% of twins after reduction. This rate was also similar to that of nonreduced twins: 7.7% (Quest) and 8.4% (Wayne State University). The mean gestational age at delivery for expectantly managed triplets (32.9 +/- 4.7 weeks) was significantly shorter than for triplets reduced to twins (35.6 +/- 3.1 weeks). By comparison, nonreduced twins had a mean gestational age at delivery of 35.8 +/- 3.9 weeks for Quest and 34.4 +/- 3.6 weeks for Wayne State University. Mean birth weights were significantly lower in expectantly managed triplets as compared with triplets undergoing reduction to twins (1636 +/- 645 g vs 2381 +/- 602 g, respectively). Nonreduced twins had a mean birth weight of 2254 +/- 653 g for Quest and 2123 +/- 634 g for Wayne State University. Pregnancy loss rates, mean length of gestation, and mean birth weight did not vary significantly between triplets who underwent reduction to twins and nonreduced twins.


CONCLUSIONS
Reduction of triplets to twins significantly reduces the risk for prematurity and low birth weight and may also be associated with a reduction in overall pregnancy loss. This suggests that multifetal pregnancy reduction of triplets to twins is a medically justifiable procedure not only from an actuarial viewpoint but also from the ethical perspective of supporting patients' autonomy and respect for patients' individual circumstances.
D000022:Abortion, Spontaneous / Q000453:epidemiology; D001724:Birth Weight; D005260:Female; D005865:Gestational Age; D006801:Humans; D007752:Obstetric Labor, Premature / Q000453:epidemiology; D011247:Pregnancy; D011256:Pregnancy Outcome; D018607:Pregnancy Reduction, Multifetal; D011272:Pregnancy, Multiple; D014310:Triplets; D014427:Twins