Analysis Of Pregnancy Outcomes Of Multiple Pregnancy Conceived By Assisted Reproductive Technology

With the widely use of assisted reproductive technology(ART), a series of iatrogenic problems have been being concerned increasingly, and one of the most striking one is multiple pregnancy after ART. With poor pregnancy outcomes, the multiple pregnancy is a kind of high-risk pregnancy. But now, few study has concerned about the prognosis of multiple pregnancy conceived by ART. This paper aims to analyze the incidence of multiple pregnancy after ART and the pregnancy outcomes after different clinical treatments, in order to provide theoretical support for future clinical practice.Objectives To estimate the incidence rate and conceivable related factors of growth discordance(DT)in twins conceived by ART, the incidence and the pregnancy outcomes after different managements of monozygotic twin(MZT). To evaluate the influence of multifetal pregnancy reduction(MFPR) on the pregnancy outcomes through comparison the pregnancy outcomes in twins from reducing high-order multiple pregnancies(HOMP) and in non-reduced twins. Reviewing outcomes following reductions in trichorionic triplet pregnancies at our institution to confirm whether reduction to one rather than two provides a better outcome.Contents and Methods All clinical pregnancies conceived by assisted reproductive technology in the reproductive center of Tianjin central hospital of Obstetrics and Gynecology during January, 2005 and December, 2014 were studied. A total of 8517 clinical pregnancies were diagnosed: 2436 twin pregnancies, 345 HOMP. Overall, 100 MZT pregnancies including 50 MZT and 50 HOMP were identified. 1. Intrapair birth weight difference?20% were determined as the discordant twins(exclude MZT). Compared clinical data between the discordant twins and concordance twins to analysis conceivable related factors of growth discordance in twins. 2. Collecting all the MZT pregnancies to estimate the incidence rate of MZT pregnancies, retrospective analysis of the outcomes of different managements of MZT. 3. Compared the outcomes of twin pregnancies, derived from ART, with and without fetal reduction, to evaluate the influence of multifetal pregnancy reduction(MFPR) on the pregnancy outcomes; Retrospective analysis of the outcomes of trichorionic triamniotic triplets reduced to singletons or twins to confirm whether reduction to one rather than two provides a better outcome.Results 1. The incidence of premature deliveries in dizygotic twins was 63.41%. The incidence of pregnancy complications was 22.40%, mainly including premature rupture of membrane, pregnancy induced hypertension and gestational diabetes mellitus. According to the twin birth weight and gestational age figure, the birth weight curve increased straightly to 38 th week and after the 38 th week, the birth weight curve decreased gradually. The incidence of DT was 14.89%. Compared clinical data between the DT group and CT group, we found that the maternal age was remarkable higher in the DT group(30.94±4.09 vs 30.33±3.76, P=0.02), and the rate of frozen thawed embryo transfer was obviously higher in the DT group(54.67% vs 42.43%, P=0.00), the Pearson contingency coefficient r=0.08. And the DT group has a higher low birth weight incidence(54.56% vs 35.38%, P=0.00), a higher pregnancy complications incidence(28.57% vs 21.32%, P=0.01)and more different-sex twin pairs(59.92% vs 49.03%, P=0.00). 1. A total of 103 of 8517 pregnancies(1.21%)were MZT. Of these, 50 cases were MZT, 53 cases were part of 50 cases HOMP(MZ-HOMP). A statistically significant difference in gestational age of delivery(38.11±1.19 vs 35.73±2.25, P=0.03)and birth weight(3176.00±298.13 vs 2418.03±400.47, P=0.00)was seen when compared the MZT which had a partial spontaneous reduce(PSR) and non-reduced MZT. In the MZ-HOMP group, none had a complete spontaneous reduction(CSR) while in the MZT 24.00% had a CSR. A statistically significant difference in gestational age of delivery(37.89±2.39 vs 34.95±2.48, P=0.00)and birth weight(2979.26±635.67 vs 2106.25±632.52, P=0.00)was seen when compared the MZ-HOMP which reduced the MZT and reserved MZT. 2. The twins derived from fetal reduction(fetal reduction group) was associated with a higher incidence of DT(21.86% vs 4.89%, P=0.01), higher incidence of low birth weight(43.44% vs 38.24%, P=0.00) and higher incidence of pregnancy complications(28.96% vs 22.40%, P=0.04) than the nonreduced group(original twins). But there was no difference between the two groups in gestational age of delivery. Trichorionic triplet pregnancies which reduced to singleton(singleton group) had a lower incidence of premature delivery(13.64% vs 61.20%, P=0.00), a lower incidence of low birth weight(9.09% vs 43.44%, P=0.00), a lower incidence of pregnancy complications(9.09% vs 28.96%, P=0.01), a higher gestational age of delivery(37.94±1.66 vs 35.85±2.04, P=0.00) and a higher birth weight(3152.73±500.56 vs 2481.17±496.37, P=0.00) than which reduced to twins(twin group). And there was no difference between the two groups at pregnancy loss rates(16.67% vs 9.36%, P=0.13)and take baby home rates(81.48% vs 90.15%, P=0.08).Conclusions 1. The incidences of twin pregnancy and triplet pregnancy after ART are respectively28.60%, 4.05%. 2. The birth weight of twins increased straightly to 38 th week and after the 38 th week, the birth weight curve decreased gradually. It reminds us twins growth can not reach their potential because of the limited resources of utero. 3. The incidence of DT was 14.89%, close to 11.11% reported in the literature. The older maternal age, frozen thawed embryo transfer, pregnancy complications and discordant sex maybe the related factors for the higher incidence rate of growth discordance in twins conceived by ART. 4. The incidences of MZT pregnancies after ART is 1.21%. 5. The MZT which had a PSR had a better pregnancy outcomes than non-reduced MZT. 6. Compared to MZT pregnancies, MZ-HOMP pregnancies had a lower incidence of CSR. According to the literature, the presence of an extra singleton pregnancy accompanying the MZ pregnancy appeared to offer some protection from CSR. 7. The MZ-HOMP pregnancies which reduced the MZT had a better outcomes than which reserved MZT. 8. HOMP pregnancies after fetal reduction were still associated with poorer pregnancy outcomes. These results provide an additional reason to limit the number of embryos transferred during IVF. 9. Trichorionic triplet pregnancies reduced to one rather than two fetuses led to significantly higher term delivery rate without significant differences in fetal loss rate or take-home baby rate.