[Clinical analysis of 102 cases of labor induction in the third trimester on twin pregnancy].

Objective: To investigate the clinical characteristics of induced labor in twin pregnancy and the related factors of induced labor failure. Methods: The clinical data of twin pregnant women who underwent induced labor in Peking University Third Hospital from January 2016 to December 2022 were retrospectively analyzed. According to whether they had labor or not after induction, pregnant women were divided into the success group (pregnant women who had labor after induction, 72 cases) and the failure group (pregnant women who did not have labor after induction, 30 cases). Logistic regression was used to analyze the related factors of induction failure in twin pregnant women. Results: The parity and cervical Bishop score in the failure group were significantly lower than those in the success group, while the proportion of dichorionic diamniotic twins, assisted reproductive technology pregnancy and cervical Bishop score <6, postpartum hospital stay and total hospital stay in the failure group were significantly higher than those in the success group (all P<0.05). The proportion of induced labor by artificial rupture of membranes ± oxytocin intravenous infusion in the success group was 72.2% (52/72), which was significantly higher than that in the failure group (46.7%, 14/30; P=0.030). There were no significant differences between the two groups in the gestational age at delivery, the incidence of severe postpartum hemorrhage and blood transfusion, the amount of postpartum hemorrhage, the neonatal weight of two fetuses, the incidence of neonatal asphyxia, and the proportion of neonates admitted to the neonatal intensive care unit (all P>0.05). There were no severe perineal laceration and hysterectomy in all pregnant women. Multivariate logistic regression analysis showed that primipara (OR=3.064, 95%CI: 1.112-8.443; P=0.030) and cervical Bishop score <6 (OR=5.208, 95%CI: 2.008-13.508; P=0.001) were the independent risk factors for induction failure in twin pregnancy. Conclusions: Elective induction of labor in twin pregnancy is safe and feasible. It is helpful to improve the success rate of induction of labor by strictly grasping the timing and indications of termination of pregnancy, choosing the appropriate method of induction according to the condition of the cervix, and actively promoting cervical ripening.

[Clinical features of vaginal trial delivery in twin pregnancy and factors related with failure].

Objective: To investigate the case characteristics and factors related with failure of vaginal trial delivery in twin pregnancy. Methods: A retrospective analysis was performed on the clinical data of patients with twin pregnancy who underwent vaginal trial delivery in Peking University Third Hospital from January 2016 to June 2021. There were 109 cases in the successful group (vaginal delivery of both fetuses) and 28 cases in the failed group (cesarean delivery of one or all fetuses), the differences between the two groups were compared and the related factors of vaginal trial failure in twin pregnancy were analyzed. Results: There was no significant difference in age between the two groups[(32.4±3.8) years vs (31.3±3.3) years, P=0.163].The proportion of conception through assisted reproductive technology and induced labor in the successful group was significantly lower than that in the failed group(36.7% vs 60.7%, P<0.05;35.8% vs 60.7%, P<0.05). The average gestational age [(35.5±1.9) weeks vs (36.7±2.1) weeks, P<0.05], the body weight of the first fetus[ (2 328.4±431.9) g vs (2 585.7±443.9) g, P<0.05], the body weight of the second fetus [(2 286.2±434.8) g vs (2 531.8±574.8) g, P<0.05] and the sum of the body weight of the two fetuses[(4 614.6±801.9) g vs (5 117.5±916.1) g, P<0.05] in the successful group were significantly lower than those of the failure group. Multivariate analysis showed that assisted fertility technique (OR=2.878, 95%CI:1.167-7.099) and the sum of the body weight of the two fetus ≥4 735g (OR=4.304, 95%CI:1.659-11.165) were independent risk factors for vaginal trial failure of twin pregnancy. Conclusions: Vaginal trial delivery in twin pregnancy is relatively safe. Vaginal delivery should be carefully selected for patients with twin pregnancy who concepted through assisted reproductive technology and the sum of the body weight of the two fetus ≥4 735g.

[Effects of gestational weight on the association between serum high sensitivity C reaction protein and gestational diabetes mellitus among twin gestations: A cohort study].

OBJECTIVE: To investigate the association between serum high sensitivity C-reaction protein (hsCRP) in early pregnancy and gestational diabetes mellitus (GDM) among twin pregnant women, and to explore the effects of the pre-pregnant body mass index (BMI) and gestational weight gain (GWG) status on such association. METHODS: Twin pregnant women with pre-pregnant BMI greater than or equal to 18.5 kg/m2 were recruited at Department of Obstetrics and Gynecology of Peking University Third Hospital from March 2017 to December 2020. Serum samples collected in early pregnancy were analyzed for hsCRP using particle-enhanced immunoturbidimetric method. In the following visits, the information about GWG and GDM were prospectively collected in every trimester. The association effect between hsCRP tertiles and GDM were estimated using Logistic regression, and further converted into risk ratio (RR). Cochran-Mantel-Haenszel test and mediation analysis were used to explore the effects of BMI and GWG status on the association. RESULTS: Among the included 570 twin pregnant women, 31.6% deve-loped GDM, 26.1% were pre-pregnant overweight or obesity, and 49.5% with GWG out of referenced range. After adjustment for confounding factors, risk of developing GDM in twin gestations with the middle tertile and highest tertile of serum hsCRP in early pregnancy were 1.42 fold (95%CI: 1.02-1.89) and 1.54 fold (95%CI: 1.12-2.02), respectively, compared with the lowest tertile of serum hsCRP, and there existed significantly linear trend (P=0.022). Findings from mediation analysis illustrated that pre-pregnant BMI had partial mediating effect on the association, and BMI accounted for 23.84% (P < 0.001) of the increasing GDM risks with elevated hsCRP. Joint analysis with hsCRP and GWG found that those who were with GWG out of referenced range accompanied with the higher hsCRP tertiles (>1.21 mg/L) had significantly 2.31 fold increased risk according to those who were with GWG in the referenced range accompanied with the lowest hsCRP tertile (≤1.21 mg/L, P < 0.01). CONCLUSION: Elevated hsCRP in early pregnancy significantly increased GDM risk among twin pregnant women. The hsCRP-GDM association was dependent on GWG status, and pre-pregnant BMI had partial mediating effect on such association. It is suggested that twin pregnant women should consider systemic inflammation and gestational weight at the same time to reduce GDM risk.

[Diagnosis, treatment and outcome of adnexal torsion at different gestational weeks during pregnancy].

Objective: To investigate the clinical characteristics, diagnosis, treatment and outcome of adnexal torsion at different gestational weeks during pregnancy. Methods: A retrospective analysis was conducted of the clinical data of 24 pregnancy patients with adnexal torsion, aged 21-38 (30.6±4.4) years old, who were admitted and delivered in Peking University Third Hospital from 2015 to 2019. According to the gestational age, all patients were divided into two groups:<28 weeks group (11cases) and ≥28 weeks group (13 cases), to compare the intergroup differences in clinical characteristics, treatment and outcome, and the differences of clinical data and outcome between two groups were compared. Results: The proportion of patients with twin pregnancy and assisted reproductive technology in the<28 weeks group was significantly higher than that in the ≥28 weeks group (5/11 vs 1/13, 8/11 vs 1/13, P<0.05). No significant differences between the two groups were recorded in terms of the size of the adnexal mass, the cycles of torsion and the duration from onset to operation. Compared with the≥28 weeks group, the adnexal removal rate of the<28 weeks group was lower (3/11 vs 6/13), but the difference was not statistically significant. The proportion of blood flow signals of ultrasound before operation, cases undergoing laparoscopic surgery and cases whose pathological findings were physiological cysts in the<28 weeks group were significantly higher than that in the ≥28 weeks group (8/11 vs 4/13, 8/11 vs 0, 8/11vs 4/13; P<0.05). Concerning the pregnancy outcomes, there was no difference in the mode of delivery, the delivery gestational age and the body weight of newborns between the two groups. Conclusions: The patients with adnexal torsion prior to 28 weeks(<28 weeks)of pregnancy were more likely to be conceived by assisted reproductive technologies, and the etiology was more likely to be ovarian physiological cysts. Both laparoscopy and laparotomy were safe and effective in the treatment of adnexal torsion with good outcome for mother and infant in the study.

[Thyroid function of first-trimester twin pregnant women and its association with preterm delivery].

OBJECTIVE: To describe the thyroid function abnormality of first-trimester twin pregnant women according to different references, and to explore its association with preterm delivery. METHODS: Participants, first-trimester twin pregnant women, were recruited at Peking University Third Hospital from March 2017 to February 2020. The thyroid hormone reference for ordinary adults identified on the assay kits by Siemens incorporation, thyroid hormone reference specifically for singleton pregnancy established previously, and thyroid hormone reference specifically for twin pregnancy established previously were used in the description of hypothyroidism and hyperthyroidism for first-trimester twin pregnant women. Thyroid autoantibody reference identified on the assay kits by Siemens incorporation was used in the description of positive thyroid autoantibody. Multivariable log-binomial regression was conducted to examine the association between thyroid function and preterm delivery, in which normal pregnant women according to the three references and normal pregnant women according to twin pregnancy reference accompanied with negative thyroid autoantibody were taken as control respectively. RESULTS: A total of 570 twin pregnant women were finally included. Rates of hypothyroidism according to the three references were 1.2%, 1.6% and 3.5%, respectively. Rates of hyperthyroidism according to the three references were 32.6%, 18.1% and 1.1%, respectively. After adjustment for potential confounding factors, risk of preterm delivery significantly increased in pregnant women with hyperthyroidism according to the twin specific pregnancy reference [adjusted relative risk (ARR)=1.41, 95%CI: 1.14-1.75], while no significant increase was found in those with normal thyroid function according to the twin specific pregnancy reference but hyperthyroidism according to the singleton specific pregnancy reference (ARR=1.00, 95%CI: 0.81-1.25) and in those with hyperthyroidism purely according to the ordinary adult reference (ARR=1.06, 95%CI: 0.85-1.32), compared with those normal according to all the references. Risks of preterm delivery almost significantly or significantly increased in pregnant women with hypothyroidism according to the ordinary adult or singleton specific pregnancy reference (ARR=1.40, 95%CI: 0.88-2.22) and those with hypothyroidism according to the twin specific pregnancy reference (ARR=1.53, 95%CI: 1.03-2.28). Overall analysis of thyroid function according to the twin specific pregnancy reference and thyroid autoantibody showed that risks of preterm delivery almost significantly or significantly increased in pregnant women with simple hypothyroidism (ARR=1.46, 95%CI: 0.93-2.27), simple positive thyroid autoantibody (ARR=1.32, 95%CI: 1.15-1.52), and hypothyroidism accompanied with positive thyroid autoantibody (ARR=1.78, 95%CI: 1.30-2.44), compared with those normal according to the twin specific pregnancy reference with negative thyroid autoantibody. CONCLUSION: The ordinary adult reference and that of singleton pregnancy may lead to under-diagnosis of hypothyroidism and over-diagnosis of hyperthyroidism in first-trimester twin pregnant women. Compared with pregnant women with normal thyroid function, those missed in the diagnosis of hypothyroidism were at a higher risk of preterm delivery, while those over-diagnosed as hyperthyroidism had a similar risk of preterm delivery, indicating a need to develop and generalize twin-pregnancy-specific reference on common indicators of thyroid function. Moreover, the thyroid autoantibody should be taken into consideration in the prenatal diagnosis and treatment to twin pregnant women with hypothyroidism.

[Effect of placental vascular distribution on residual anastomoses after fetoscopic laser surgery for twin to twin transfusion syndrome].

Objective: To investigate the effect of placental vascular distribution on residual anastomoses (RA) after fetoscopic laser occlusion of chorioangiopagous ressels (FLOC) for twin to twin transfusion syndrome (TTTS). Methods: A total of 57 cases of TTTS after laser surgery were retrospectively analyzed from April 2014 to April 2019 in Peking University Third Hospital. The patients were divided into RA group (24 cases) and non-RA group (33 cases) according to whether RA occurred in the placenta after laser surgery. The clinical characteristics, perioperative conditions, pregnancy outcomes and placental structure characteristics of the two groups were compared. Multivariate logistic regression was used to analyze the risk factors of placental vascular distribution for RA. The RA group was further divided into non-remission group and remission group, and the placental characteristics and pregnancy outcome of the two groups were compared. Results: (1)General clinical characteristics: the age, application of assisted reproductive technology, incidence of gestational hypertension, gestational diabetes mellitus, preoperative maximum amniotic fluid depth of the donor and recipient twins, Quintero stage and placental position of TTTS patients in the two groups were compared respectively, and there were no statistically significant differences (all P>0.05).The gestational age of patients received FLOC in the RA group was significantly higher than the non-RA group [(23.0±2.4) vs (21.9±2.7) weeks, P=0.033].(2) Perioperative conditions and pregnancy outcomes: the delivery gestational age of the RA group was significantly lower than that of the non-RA group (median:31.8 vs 34.4 weeks, P=0.002);The newborn birth weight in the RA group was significantly lower than that in the non-RA group [(1 648±597) and (2 013±481) g, P=0.003].The birthweight difference in the RA group was significantly higher than that in the non-RA group (median:0.30 vs 0.11, P=0.005). (3) The placental structure and the risk factors influencing RA happened: the differences in the proportion of four types of placental vascular distribution in the RA group and non-RA group were different significantly (χ²=10.214, P=0.012), with a detail of parallel type 29% (7/24) and 3% (1/33), staggered type 58% (14/24) and 76% (25/33), hybrid 8% (2/24) and 21% (7/33), monoamniotic membrane type 4% (1/24) and 0 respectively. Multivariate logistic regression analysis showed that parallel placental vascular distribution was an independent risk factor for RA after FLOC (OR=24.5, 95%CI 1.7-336.2, P=0.017). (4) Placental characteristics and pregnancy outcomes in the remission and non-remission groups of the RA group: the incidence of three kinds of anastomoses, the total number, total diameter and proportion of RA, and the placental territory discordance ratio were compared between the two groups, and there were no statistical significances (P>0.05);The birth weight difference ratio in the non-remission group was higher than that in the remission group (median:0.41 vs 0.28, P=0.036). Conclusion: The parallel type of placental vascular distribution may be an independent risk factor for RA in TTTS after laser surgery.

[Perinatal outcomes of dichorionic triamniotic triplet pregnancy].

Objective: To analyze the perinatal outcomes in different methods of multifetal pregnancy reduction in dichorionic triamniotic (DCTA) triplet pregnancy. Methods: A retrospective analysis was performed on 57 cases of DCTA triplets in Peking University Third Hospital from January 1, 2010 to January 1, 2020, including 27 cases in expectant pregnancy group and 30 cases in selective fetal reduction (FR) group. The selective FR group was further divided into 3 subgroups according to different FR methods:retaining monochorionic dichorionic (MCDA) group, retaining dichorionic dichorionic (DCDA) group, and retaining singleton group. The perinatal outcomes of expectant pregnancy group and 3 subgroups of selective FR group were compared. Results: The gestational weeks in selective FR group was (34.5±5.7) weeks, and full-term delivery rate was 53% (16/30), respectively higher than those of the expectant pregnancy group (29.9±6.0) weeks and 7% (2/27). The miscarriage rate of the selective FR group was 10% (3/30), lower than that of the expectant pregnancy group (33%, 9/27). The differences between the two groups were statistically significant (all P<0.05). The ratios of pregnancy complications and newborn admission to neonatal ICU (NICU) in the selective FR group were lower than those of the expectant pregnancy group (all P<0.05). In the selective FR group, the gestational weeks in retaining MCDA group (6 cases), retaining DCDA group (13 cases), and retaining singleton group (11 cases) were (32.2±4.3), (33.0±6.3), and (37.4±4.7) weeks; the miscarriage rates were 1/6, 1/13, and 1/11; the premature delivery rates were 4/6, 7/13, and 0/11; the full-term delivery rates were 1/6, 5/13, and 10/11; pregnancies with at least 1 survivor rates were 5/6, 12/13, and 10/11; NICU occupancy rates were 6/8, 9/18 and 0/10, respectively. The retaining singleton group had the highest rate of full-term delivery and the lowest rate of NICU occupancy. Compared with other groups, the differences were statistically significant (all P<0.05). The full-term delivery rate was significantly higher in the retaining DCDA group than that of the expectant pregnancy group (P<0.05). Conclusions: The risk of DCTA triplet pregnancy is high. Reduction of the MCDA pair to singleton has the highest rate of full-term delivery and the lowest rate of NICU occupancy. For pregnant women who wish to retain twin pregnancy, the risk should be fully informed, and consider reduction of one fetus of the MCDA and retaining DCDA twins to continue pregnancy.

[Analysis of clinical characteristics of discordant structural malformations in one of monochorionic diamnionic twins].

Objective: To analyze the clinical characteristics of structural malformations in one of monochorionic diamnionic twins (MCDA). Methods: The clinical data of 77 MCDA patients with structural malformations diagnosed by ultrasound were retrospectively reviewed from January 2012 to May 2017. The distribution of structural malformations, prenatal chromosomal karyotyping and pregnancy outcomes were analyzed. Results: (1)Among the 77 MCDA patients with structural malformations, the single malformation accounted for 79%(61/77), the multiple malformations accounted for 21%(16/77). And there were a total of 94 types of malformations, the top three malformations were neurological malformations (32%, 30/94), cardiovascular malformations (29%, 27/94) and twin reversed arterial perfusion sequence (TRAPS;10%,9/94).(2)Among the 77 patients with structural malformation, 64 cases (83%, 64/77) were examined for fetal chromosomes, of whom 14 cases (22%,14/64) were examined for fetal chromosomes of both twins, with 1 case (1/14) of discordant fetal chromosome. (3)Among the 77 patients, 4 cases (5%, 4/77) with severe fetal malformations terminated pregnancy. Totally 29 cases (38%,29/77) with severe malformations were treated with selective fetal reduction, among whom 7 cases (24%, 7/29) experienced unexplained fetal death within 24 hours after the operation; 2 cases (7%, 2/29) happened inevitable abortion, and 2 cases (7%, 2/29) underwent unexplained fetal death during the late pregnancy. Of the remaining 44 patients (57%,44/77) with expectant treatment, 13 cases (30%,13/44) occurred twin transfusion syndrome (Ⅱ-Ⅳ), and were treated with fetoscopic laser occlusion. Eight patients had 2 survival twins, 4 patients delivered 1 survival twin, and 1 patient had dead twins. Conclusions: The most common malformations in MCDA twins are the nervous malformations, cardiovascular malformations and TRAPS. The chromosome karyotype of MCDA twins with structural malformations are sometimes discordant, and separate samling of the twins is suggested for prenatal diagnosis. Selective fetal reduction could be given to severe structural malformation in MCDA patients safely and effectively. For non-severe structural malformation in MCDA patients with twin transfusion syndrome, fetoscopic laser occlusion is safe and effective.

[Clinical outcome and placenta characteristics of spontaneous twin anemia-polycythemia sequence].

Objective: To investigate the clinical outcome and placental characteristics of spontaneous twin anemia-polycythemia sequence (sTAPS). Methods: Twelve cases with sTAPS delivered in Peking University Third Hospital from May 2013 to August 2016. The data of ultrasound characteristics, gestational age at delivery, and 1 minute Apgar score were analyzed, retrospectively. Placental superficial vascular anastomoses, placental territory discordance and the ratio of umbilical cords insertion distance to the longest placental diameter were also analyzed. Results: (1) Only 1 case of sTAPS was diagnosed prenatally, the others were diagnosed postnatally because the fetal middle cerebral artery(MCA) doppler was not measured regularly. Five cases were complicated with selective intrauterine growth restriction (sIUGR). The median gestational age at delivery was 32.8 weeks (31-37 weeks) . The pregnancies were terminated because 3 cases were sIUGR type Ⅰ, 1 case was sIUGR type Ⅱ, 1 case was sIUGR type Ⅲ, 2 cases were fetal distress, 2 cases were severe pre-eclampsia, 2 cases were premature rupture of membrane, 1 case was fetal hydrops with abnormal doppler waveforms of ductus venouses. (2) When 5 sIUGR cases were excluded, there was no difference between the twins in birth weight [1 797 g (940-2 620 g) , 1 648 g (980-2 500 g) ; P=0.688]. The hemoglobin (Hb) level in all donor was significantly lower than recipient (P=0.000) and the inter-twin Hb difference was 147.6 g/L (84.0-216.0 g/L). While the reticulocyte percentage in donor was significantly higher than recipient (P=0.013) and reticulocyte percentage ratio was 3.60 (1.04-7.50). Five donor newborns had neonatal asphyxia, including 1 severe asphyxia, while no asphyxia happened in the recipient twins. (3) Arterio-arterial (A-A) anastomoses, veno-venous (V-V) anastomoses, arterio-venous (A-V) anastomoses were found in 3, 1 and 11 placentas, respectively. The total number of anastomoses was 2 (1-5) and the total diameter was 1.1 mm (0.4-2.1 mm), including 0 (0-1) A-A anastomoses with 0.2 mm (0.0-0.9 mm) in diameter and 2 (0-5) A-V anastomoses with 0.7 mm (0.0-2.1 mm) in diameter. The placental territory discordance was 0.17 (0.02-0.40) and the ratio of umbilical cords insertion to the longest placental diameter was 0.82 (0.34-0.99). Conclusions: The pathogenesis of sTAPS might result from slow and chronic blood transfusion from donor to recipient through a few minuscule vascular anastomoses in the placenta. In all monochorionic twins, especially sIUGR cases, MCA doppler should be monitored closely in the second and third trimester, in order to diagnose and manage sTAPS in time.

[The prognosis of Monochorionic co-twin after single intrauterine fetal demise].

Objective: To analyze the prognosis of surviving monochorionic co-twin after single intrauterine fetal demise (sIUFD). Methods: Retrospectively analyzed the twin pregnancy cases admitted in Peking University Third Hospital between Jan 2008 and Feb 2015. We recorded perinatal characteristics, neuroimage in co-twin, and followed up the neonatal outcome. Results: 47 cases were found, including 45 cases of monochorionic diamniotic (MCDA) and 2 cases of monochorionic monoamniotic (MCMA). Median gestational age at sIUFD was 27 weeks.Median interval between sIUFD and birth was 3.3 weeks.Median gestational age at birth was 34.2 weeks.The causes of sIUFD were: MCMA (2/47, 4.3%), sIUGR (11/47, 23.4%), twin-twin transfusion syndrome (TTTS) (16/47, 34.0%) or TTTS complicated with sIUGR (3/47, 6.4%). In the sIUGR pregnancies, sIUFD occurred all in the growth-restricted fetus.In the TTTS pregnancies, sIUFD always occurred in donors (15/16, 93.8%). There were 41 (87.2%) live-born co-twins.Among the live births, fetal cranial ultrasound showed that 7 neonatus got intraventricular hemorrhage.There were 6 neonatus dead in first 28 days.All of the 35 survivors whose follow up from 12 to 70 months, responses were all received and nobody had cerebral palsy. Conclusion: sIUFD always occurred in the growth-restricted fetus and the donor-twins. There was nobody had cerebral palsy in the survivors.