Introduction
Advanced maternal age and widely application of assisted reproductive technologies have led to an increase in multiple gestations. Twins, triplets, and higher-order multiple gestations now account for more than 3% of all live births.1 It is well known that multiple gestation is associated with an increased risk of maternal complications, as well as high perinatal morbidity and mortality.2
Because triplet or higher-order multiple gestation are more likely to develop these risks, several preventive strategies to limit the number of fetuses are suggested. Elective single embryo transfer (eSET) and multifetal pregnancy reduction (MFPR) are the recommended methods for this purpose. In contrast to eSET which is a relatively acceptable useful method,3,4 MFPR is a more complicated method in clinical practice, involving a number of medical, economical, psychological and ethical issues. Moreover, triplet pregnancies are more common than quadruplet or higher-order pregnancies, making MFPR in triplet pregnancy a more challenging subject.
As MFPR is not easily acceptable for infertile couples, more clear evidences are required to recommend MFPR in triplet pregnancy. Most data to advocate MFPR in triplet pregnancy were derived from comparison of maternal and perinatal outcomes between twin and triplet pregnancies, although direct comparison of outcomes between continuing triplets and reduced twin from triplets is more desirable. To show the usefulness of MFPR for triplet pregnancy, improved maternal and neonatal morbidity and mortality in reduced twin from triplets should be demonstrated, but few studies have been conducted in these points of view. Multifetal reduction of a quadruplet or higher-order pregnancy to twins has been advocated, with data showing that MFPR prolongs gestational age and increases birthweight.5,6 Nonetheless, there are conflicting data about whether pregnancies reduced from triplets to twins fare better than expectantly managed triplet pregnancies.7 Moreover, most of studies were conducted several years or decades ago. Maternal and fetal morbidity and mortality should be carefully assessed on the basis of contemporary data. To clarify this issue, we conducted this study to compare maternal, perinatal and long-term outcome of triplet pregnancies managed expectantly with those reduced to twins.