Objective To investigate the etiology of complete hydatidiform mole coexistent with live fetus (CHMCF) following assisted reproductive technologies (ART). Design Retrospective study. Setting Peking University Third Hospital and tertiary reference. Population Total of 47 patients conceived via ART and diagnosed with CHMCF, including 5 cases from our hospital and 42 cases from literature. Methods Retrospective analysis of risk factors associated with neonatal outcome and the progression of gestational trophoblastic neoplasia (GTN). Main Outcome Measures Pregnancy complications. Results Vaginal bleeding presented as the most common complication (75%). The average gestational age confirming diagnosis by ultrasound was 15.9±4.7 weeks. 40.4% of the patients progressed to GTN. 41.5% of those who chose to continue pregnancy had a favorable fetal outcome. Hyperemesis gravidarum and abdominal pain had a 33.3% and 25% occurrence rate in not surviving baby group, respectively, but not presented in surviving baby group. Hypertension emerged in a significantly earlier gestational week in not surviving baby group than the other (17.0±2.4 vs 25.3±2.3, p=0.003) . Patients who progressed to GTN had a statistically higher rate of abdominal pain (26.3% vs 3.6%, p=0.033) compared to those who did not. Conclusions For CHMCF patients via ART, the surviving baby rate is 41.5% and the GTN progression rate is 40.4%, and appearance of hyperemesis gravidarum, abdominal pain and early emerge of hypertension predicted an adverse pregnancy outcome. Occurrence of abdominal pain and early presentation of vaginal bleeding indicated a poor prognosis in GTN progression.

Abstract Objective: To analyse the impacts of fresh embryo transfer and frozen‒thawed embryo transfer cycles with different endometrial preparation protocols on clinical outcomes and placental pathology. Design: Retrospective case‒control study. Setting: Peking University Third Hospital. Population: A total of 3920 Single live birth cases after in vitro fertilization/intracytoplasmic sperm injection and embryo transfer cycles. Method: Cases were divided into the fresh embryo transfer, natural cycle (NC)-frozen-thawed embryo transfer and hormone replacement therapy (HRT)-FET groups, and clinical outcomes and placental pathology characteristics were compared. Main Outcome Measures: preterm birth, preeclampsia, postpartum haemorrhage, placenta implantation, placenta previa, placental accreta, cervical insufficiency, neonatal weight and placental pathology. Result:The risks of preeclampsia, postpartum haemorrhage and preterm birth were significantly higher in the HRT-FET group than the fresh embryo transfer and NC-FET groups (13.42% vs 5.49% vs 5.91%, 21.7% vs 12.1% vs 11.0%, 10.5% vs 7.7% vs 7.6%, p < 0.05). Birth weight was lower in the fresh embryo transfer group than the NC-FET and HRT-FET groups (p<0.05). There was no statistically significant difference in the incidence of placental structural abnormalities and pathological characteristics among the groups. Conclusion: HRT-FET cycles were associated with increased maternal and foetal complications compared to fresh embryo transfer and NC-HRT cycles. There was no significant difference in the occurrence of placental structural abnormalities or pathological changes among the transfer methods. Keywords: Fresh embryo transfer; Frozen-thawed embryo transfer; Endometrial preparation protocol; Clinical outcome; Placenta Tweetable abstract: Different Embryo Transfer techniques influence the clinical outcomes but not placental pathology .

Objective: To explore the distribution of time to pregnancy in a Chinese population based on a cross-sectional design. Design: A cross-sectional population-based study. Setting: 8 provinces/municipalities in China between 2010 and 2011. Population or Sample: 25,270 couples aged 20-49 years. Methods: Multistage stratified cluster sampling strategy was utilized to recruit participants from each stratum by district, province/municipality, town/township, and village/street order. Main Outcome Measures: Time to diagnose pregnancy from 17,275 couples “at risk for pregnancy”. Results: In 7,889 couples eligible for analysis, the mean time to pregnancy was 17.2 months (standard deviation, 22.7) with a median of 9 months (25–75th percentile, 3–20 months). Women aged 20–24 years had the highest percentage of pregnancy at 3, 6, 12, and 24 months (23.9%, 42.5%, 58.5%, and 80.4%, respectively). Furthermore, 55.8% (3,413/6,116) and 79.9% (4,885/6,116) of women aged <35 years conceived within 1 year and 2 years, respectively, and the percentage increased by only 8.4% (5,399/6,116, 88.8%) in the third year. Only 30.6% (186/607) and 50.6% (307/607) of women aged ≥35 years conceived within 1 year and 2 years, respectively. Risk factors associated with time to pregnancy were older age, lower educational attainment of couples, higher annual household income, toxic exposure in men, shorter duration of cohabitation, longer menstrual cycle interval, history of abnormal pregnancy, and nullipara. Conclusions: Our study provides a comprehensive estimation of the time to diagnose pregnancy among Chinese couples of reproductive age, providing important information for policy makers, fertility clinicians, and sexual health educators.

Objective: This study aims to provide an evidence-based assessment of the benefits and harms of four transplantation methods so as to improve the superior pregnancy outcome and reduce the pregnancy rate of multiple embryos in the Mongoloid race. Design: Retrospective analysis Setting: Double Reproductive Centers of Medical University Population or Sample: 24,422 frozen-thawed embryo transfer (FET) cycles recorded from January 2015 to May 2018. Methods：A retrospective cohort study Main Outcome Measures: Biochemical pregnancy, clinical pregnancy, monozygotic twins, miscarriage, maternal complications, live birth. Results: Of the four groups, the biochemical pregnancy rate, the clinical pregnancy rate, and the live birth rate were the lowest in the C-1 group while they were the highest in the B-2 group. However, the B-2 group was accompanied with higher risks of miscarriage, maternal complications, twin births, preterm births and low birth weights. The biochemical pregnancy rates, the clinical pregnancy rates and the live birth rates in the C-2 group and B-1 group were statistically different, with different risks for monozygotic twins, miscarriages. Conclusion: Single blastocyst transplantation seems to be the best choice for all maternal ages to greatly reduce adverse neonatal outcomes. Tweetable abstract: This was a retrospective cohort study using the ART databases from two affiliated hospitals of Peking University. 24,422 frozen-thawed embryo transfer (FET) cycles recorded from January 2015 to May 2018 were selected to generate the research database which also included maternal characteristics.