The Clinical Research Of Biochemical Pregnancy In First IVF Cycles And Its Influence On Subsequent Cycles

ObjectiveTo find out the clinical factors leading to biochemical pregnancy of in vitro fertilization and embryo transfer (IVF-ET) cycles by comparing clinical characteristics, controlled ovarian hyper-stimulation protocols, endometrium thickness and types, oocyte and embryo situations. And to identify whether biochemical pregnancy is a positive predict for the subsequent cycles.MethodsRespectively reviewed 2814 cycles in the first in vitro fertilization from July 2011 to August 2015 of Shandong University Qilu Hospital Reproductive Medical Center. Except those cycles (323clcles) who didn’t receive embryo transfer because of failure of oocyte retrieval, failure of blastocyst culture, failure of embryo cryopreservation and those cycles (74 cycles) who reached abortion, the rest 2417cases were divided into three groups:group A, lack of pregnancy (n=1143cycles); group B, biochemical pregnancy (n=163cycles); group C, clinical pregnancy (n=1111 cycles)Different protocols were applied for superovulation according to the situation of the patients. Gonadotropin (Gn) choose fruit Serono Finn (Switzerland on promoting company), and urine gonadal hormone (zhuhai pharmaceutical) method. With follicular development monitored by transvaginal B ultrasound, oocytes were collected 34～36 hours after HCG injection. IVF or ICSI were performed based on the condition of semen. According to the situation of both the patients and the embryos, embryos were transferred 3 days (cleavage embryo) or 5/6 days (blastocyst) after oocytes retrieval. The thawed embryos were transferred the next day after thawing or when they reached the blastocyst stage. The pregnancy outcome was followed-up. We compared the clinical characteristics, basic endocrine level, controlled ovarian hyper-stimulation protocols, endometrium thickness and types, oocyte and embryo situations. As to group A and group B, the pregnancy outcomes of their subsequent cycles were followed-up.For statistical analysis, we use SPSS 17.0. measures were presented as mean± standard deviation and percentage (%). Univariate was done by one-way ANOVA and R×X Chi-square test, and multivariate analysis was done by unconditioned logistic regression. A P value<0.05 was considered statistically significant.Results1. Single factor analysisCompared with group C, the Group B had higher female age and lower BMI. While group B had higher infertility fixed number of years and basic FSH level and lower basic LH level contrasting to group A. The differences were statistically different (p<0.05). The comparison of male age and proportion of embryo types between Group A and Group C is statistically different. While Group B has no difference with these two groups. However, the comparison of pregnancy frequency, artificial abortion frequency, spontaneous abortion frequency, basic E2 value, basic TSH value between the three groups had no statistical difference (p>0.05). The three groups had similar proportion of pregnancy types, semen sources, and infertile factors with the other two groups (p>0.05).The number of oocytes picked up and MⅡ oocytes of Group B were more than Group A (p<0.05). While these two indexes were similar among the Group B and Group C (p>0.05). There were statistical difference in E2, thickness and types of endometrium on the day of HCG injection of the fresh cycles between Group A and Group C (P<0.05), with no statistic difference between Group B (p>0.05).The Gn dosage, days of Gn, P value and E2/oocytes value on the day of HCG injection and fertilization types in the three groups were not statistically different. (p>0.05)The proportion of endometrium preparation modes in thawed embryos in group B had no significant different than the other two groups (p>0.05)The number of available embryos, the number of I level embryos and the proportion of I level embryos were higher than group A (p<0.05), with no statistic difference with Group B (p>0.05). The comparison of number of embryos transferred and embryo types were no significantly different between Group B and the other two groups (p>0.05)2. Multi-factor analysisWe did a muili-factor analysis between Group B and Group A with differences in the factors including infertility fixed number of years, basic FSH level, basic LH level, the number of available embryos, the number of oocytes picked up and MⅡ oocytes, the number of Grade I embryos and the proportion of Grade I embryos. It showed that infertility fixed number of years and the number of available embryos were the independent factors to biochemical pregnancy.We did a muili-factor analysis between Group B and Group C with differences in the factors including female age and BMI. It showed that BMI was the independent factor to biochemical pregnancy.3. The influence of biochemical pregnancy on subsequent cycleThe clinical pregnancy rate in the subsequent cycle of group B in no higher than group A, while the proportion of biochemical pregnancy is higher than Group A. But the difference was no significant p>0.05)Conclusions1. Women with low ovarian reserve have less chance to concept. Once they get pregnant, the chance of biochemical pregnancy will not increase.2. Elderly women are more likely to terminate at biochemical pregnancy because of lower quality of oocytes. Advanced age of men decrease clinical pregnancy rate, but it has no remarkable influence on biochemical pregnancy.3. Patients with high BMI are more likely to have biochemical pregnancy rather than clinical pregnancy. Weight reduction before IVF treatment may help improve the pregnancy outcome.4. Patients with lower embryo quality have less chance to concept. The difference of embryo quality between biochemical pregnancy and clinical pregnancy is not proved. Maybe morphological evaluation of embryo cannot entirely represent embryo developmental potentiality.5. This study didn’t prove the relationship between endometrium situation on the day of HCG injection and biochemical pregnancy. This may be related to that Two-dimensional ultrasound cannot describe endomrtrium morphology and subendometrial blood flows. It is also possible that the endometrium in IVF cycle has been adjusted to be the most suitable for embryo implantation and development, and biochemical pregnancy is more closely related to other factors.6. Women ended with biochemical pregnancy in first IVF cycle don’t have more chance for clinical pregnancy in subsequent cycle, but they have more chance for biochemical pregnancy again.