The Clinical Analysis Of Spontaneous Reduction Of Multiple Pregnancy After In Vitro Fertilization And Embryo Transfer

BackgroundSince the first test tube baby successfully born in1978, there have been over400,000children obtained through the assisted reproductive technology (ART). ART has been recognized all over the world, then the experts pay attention to the safety of the technology. Multiple pregnancy is the most common complication, spontaneous reduction (SPR) is not rare phenomenon in multiple pregnancies. Multiple pregnancy is a serious pathological pregnancy, pose a threat to the mother and child. If spontaneous reduction happens in multiple pregnancy, apparently it reduces the number of the growing fetus in uterine cavity, would the event improve the pregnancy outcomes or bring new threats to the mother and survival baby actually? There was a scarcity of information about the facet in domestic researches. In the article, we carried on a large sample study to explore these questions.ObjectiveTo explore the associated factors with SPR, and the impacts of SPR on pregnancy outcomes. MethodsThe infertile patients and their child(ren) through in vitro fertilization and embryo-transfer from1998to December2010were studied, including3957cycles and5111neonatus. According to the mode of assisted reproduction, it was divided into fresh cycle and frozen-thawed cycle, fresh cycle contained in vitro fertilization group (IVF) and intracytoplasmic sperm injection group (ICSI); According to the pregnant outcome, three groups were divided into, singleton group, twin group and triplet group. The spontaneous groups contained singleton originated from twin (2�'1), singleton originated from triplet (3�'1) and twin originated from triplet (3�'2); With respect to the time of spontaneous reduction, the survival cohort was split into≤8gestational weeks,8-18gestational weeks,≥18gestational weeks; about the multifetal reduction cycles, we compared the pregnancy outcomes between the only multifetal reduction and spontaneous reduction after embryo reduction. In the study, we analyzed spontaneous reduction rate、obstetric and neonatal outcomes.Results1. The SPR rate was bigger in triplet group than in twin group (P<0.01); The SPR incidence in frozen cycle was significantly higher than in fresh cycles (P<0.05); The incidence of spontaneous reduction was similar between IVF and ICSI group; The incidence of gestational sac loss was bigger in patients≥35years of age than<35years of age (P<0.01, OR=1.75,95%CI:1.29-2.35)2. The preterm incidence was higher in8-18weeks gestational age than≤8weeks gestational age (P<0.05); the low birth rate was higher than≤8weeks gestational age.3. According to mean birth weight、preterm rate、very low birth rate and low birth rate, the outcomes of singleton group was better than twin group or triplet group (P<0.05); The outcomes in (2�'1) group was improved than twin group (P<0.05), however, still worse than singleton group (P<0.05); The neonatal outcomes in (3�'2)group were better than the triplet group (P<0.05), still a little worse than twin group(); the neonatal outcomes of (3�'1) group were obviously improved than triplet group (P<0.05)4. The SPR incidence was13.2%after the multiple pregnancy reduction. The outcomes in SPR group were better than the twin group after reduction. Reduction of triplets to twins improved the outcomes; but worse than originally twins.5. Whether the patients underwent SPR or multiple reduction or not, the obstetric and neonatal outcomes of multiple-pregnancy group were worse than singleton group.Conclusions1. The spontaneous reduction incidence is positively associated with the pregnant age and the initial number of gestational sacs, inversely related to the embryo quality;2. The higher the gestational age at the time of embryo vanishing, the higher risk for the mother and surviving newborn;3. The spontaneous reduction and multifetal reduction can better the outcomes of the remaining fetus in some degree, however, it is negatively related to the initial number of embryos, worse than the singleton group;4. Because of spontaneous reduction, performing selective reduction after8th week of gestation age may reduce the performance of reduction procedure and its complication;5. To enhance the embryo quality、ess the embryo-transfer, especially selective top-quality single embryo transfer, is the fundamental measure to improve the obstetric and neonatal outcomes.