| In recent years,assisted reproductive technology(ART)has been used by progressively more people.According to a report by the International Committee Monitoring Assisted Reproductive Technologies,the percentage of babies born from ART was estimated to increase by an average of 9.1% per year between 2008 and 2010.In America,a total of 169,568 ART cases resulted in 56,028 live-birth deliveries with 68,782 infants born in 2014.Due to the development of assisted reproductive technology,a variety of methods have been applied to improve the implantation rate,pregnancy rate,and neonatal and maternal outcomes,one of which is blastocyst culture.There have been many studies in this area;however,this stage of embryo transfer is still a controversial issue.ObjectiveThe initial aim was to investigate the neonatal and maternal outcomes,for example,preterm birth,low birth weight,small for gestational age,large for gestational age,very preterm birth,very low birth weight,sex ratio,preeclampsia,placental abruption,placenta previa,postpartum hemorrhage and premature rupture of membranes,birth defects,perinatal mortality,Apgar score <7 at 5 min and gestational diabetes in different durations of in vitro cultures.The second aim was the factors which affected preterm birth,low birth weight,small for gestational age and large for gestational age.Materials and MethodsThis was a single-center retrospective study which was approved by the Ethics Committee of Third Affiliated Hospital of Zhengzhou University.All data were provided by The Reproduction Center,The Third Affiliated Hospital of Zhengzhou University,between January 2013 and August 2016.The data were collected and stored in our database.Women who underwent their first in vitro fertilization(IVF)/intracytoplasmic sperm injection(ICSI)embryo transfer cycle were included.We excluded patients older than 35 years to avoid age-related factors.Also excluded were patients who had intrauterine lesions and uterine malformations.We used data from fresh embryo transfers only to eliminate potential biases.Data were included only if the infants were born after twenty weeks of gestation.Stillbirths and patients who underwent preimplantation genetic diagnosis(PGD)/ preimplantation genetic screening(PGS)were also excluded.Likewise,patients with donor oocytes were excluded.We excluded patients who had transvaginal ultrasound performed 30 days after transplantation to avoid vanishing twins.Finally,1477 cycles met the inclusion criteria.Patients used Gn RH agonist(Ipsen,Boulogne-Billancourt,France)to promote ovulation.When 1-3 follicular diameter ≥ 20 mm or 60% dominated follicle ≥ 18 mm,and serum luteinizing hormone(LH),estrogen(E2),progesterone(P)levels were appropriate,250 μg of recombinant human chorionic gonadotropin(Merck,Darmstadt,Germany)were injected.After 36-38 h,oocyte retrieval took place under ultrasonography.According to the stage of the embryo,transplant surgery took place at 3,5 or 6 days after ovulation.Luteal support was administered after oocyte retrieval.Patients had two options for luteal support.The first was 60 mg im qd Progesterone injection(Xianju,Zhejiang,China)and 20 mg po bid dydrogesterone tablets(Abbott,Illinois,America).The other was 90 mg intravaginal administration qd Progesterone Sustained-Release Vaginal Gel(Merck,Darmstadt,Germany)and 20 mg po bid dydrogesterone tablets(Abbott,Illinois,America).The luteal support continued to 45 days after transplantation.We compared the neonatal and maternal outcomes of IVF/ICSI pregnancy after blastocyst embryo transfer vs cleavage stage embryo transfer by SPSS(Statistical package for the social sciences)software 22.0.For categorical variables,we used chi-square tests.If more than 20% of cells had an expected count lower than 5,we used Fisher’s exact test.For continuous variables,we used the Student’s t-test or Mann-Whitney test.We also used binary logistic regression to analysis preterm birth,low birth weight,large for gestation age and small for gestation age.According to previous studies,these factors have been analyzed using binary logistic regression.Other factors analyzed include maternal age(categorical: ≤30y,>30y),male age(continuous variable),method of treatment(categorical: IVF,ICSI),type of infertility(categorical: primary infertility,secondary infertility),years involuntary childlessness(continuous variable),parity(categorical: 0,≥1),body mass index(continuous variable),reason for infertility(categorical: male factor,tubal factor,other),number of retrieved oocytes(continuous variable),delivery mode(caesarean section,spontaneous delivery),endometrial thickness(continuous variable)and stage of embryos transferred(categorical: cleavage stage embryos or blastocyst).Results(1)Baseline data: maternal age,male age,the type of infertility,years of unwanted childlessness,parity,body mass index,reason for infertility,endometrial thickness and transplantation time did not have significant difference in two groups.However,the method of treatment and number of retrieved oocytes had significant between two groups.(2)Maternal outcomes: blastocyst group and cleavage stage group had similar maternal outcomes for preeclampsia,placental abruption,placenta previa,postpartum hemorrhage,premature rupture of membranes and gestational diabetes.(3)Neonatal outcomes: a high risk of sex ratio imbalance toward males was found in blastocyst group(p=0.01).And there was a high risk of preterm birth after blastocyst(9.9% vs 5.7%,p=0.02)transfer.However,for the Z-scores,very preterm birth,low birth weight,large for gestational age,small for gestational age,very low birth weight,birth defects,perinatal mortality and Apgar score <7 at 5 min,there was no difference after cleavage stage embryo transfer.(4)The factors affected preterm birth,low birth weight,small for gestational age and large for gestational age:In terms of preterm birth,blastocyst transfer had an adverse outcome compared with cleavage stage embryo transfer(COR 1.86,95% CI 1.10-3.17;AOR 2.19,95% CI 1.15-4.18,P=0.02).Patients who had more years of involuntary childlessness had a higher risk of low birth weight(COR 1.11,95%CI 1.01-1.22;AOR 1.16,95%CI 1.03-1.30,P=0.01).We found that thin patients were more likely to give birth to small for gestational age infants(COR 0.86,95% CI 0.80-0.92;AOR 0.86,95% CI 0.80-0.92,P=0.00).Five risk factors for large for gestational age infants were relevant.Secondary fertility(COR 1.03,95% CI 0.76-1.40;AOR 0.59,95% CI 0.40-0.89,P=0.01),short duration of infertility(COR 0.98,95% CI 0.92-1.04;AOR 0.92,95% CI 0.85-0.99,P=0.02),nulliparous women(COR 1.78,95% CI 1.14-2.77;AOR 1.89,95% CI 1.09-3.28,P=0.02)and fat patients(COR 1.17,95% CI 1.11-1.22;AOR 1.15,95%CI 1.10-1.21,P=0.00)all had a low risk of delivering a large for gestational age infant.Large for gestational age infants also had a larger caesarean section ratio(COR 3.08,95% CI 2.08-4.57;AOR 2.79,95% CI 1.86-4.19,P=0.00).Conclusions(1)There was a high risk of preterm birth after blastocyst transfer.And a high risk of sex ratio imbalance toward males was found in blastocyst group.There was no significant difference in maternal outcomes between two groups.(2)Body mass index was found to be an important factor in gestational age.The type of infertility,years of involuntary childlessness,parity,delivery method and body mass index were related to large for gestational age infants. |
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