Amniocentesis and the risk of second trimester fetal loss in twin pregnancies: results from a prospective observational study

Abstract

Aim: To compare the rate of pregnancy loss between twin pregnancies undergoing a genetic amniocentesis (AC) and a control group with similar characteristics.

Methods: Prospective observational study on a population of twin pregnancies referred to our prenatal diagnosis unit for screening from 1990 to 2010. Those women referred for an AC were compared with those without indication for the procedure. Primary outcomes were pregnancy loss within the 4 weeks after procedure and pregnancy loss before 24 weeks. Secondary outcome included neonatal morbidity, gestational age at delivery and birth weight.

Results: Maternal characteristics were similar for both groups, except for maternal age. There was neither difference in the pregnancy loss rate within 4 weeks (2.7 versus 2.6%) nor in the loss rate before 24 weeks of gestation (1.2 versus 1.1%). Gestational age at birth was 36 weeks for both groups. Chorionicity and gestational age at procedure played no role in modifying the risk.

Conclusion: Based on our results, there is no difference in the pregnancy loss rate in twin gestations, regardless of chorionicity or gestational age at procedure, either within 4 weeks after the procedure or before 24 weeks, in patients who undergo AC when compared with patients who do not.     

Modifiable risk factors for growth restriction in twin pregnancies

OBJECTIVE: This study was undertaken to evaluate modifiable risk factors for adverse fetal growth in twin pregnancies. STUDY DESIGN: A large cohort study from a database of women with twin gestations identified at risk for preterm labor was performed. Examining each infant's birth weight and gestational age at delivery, infants were classified as being average (AGA), large (LGA), or small (SGA) for gestational age, using the Alexander reference curve. Clinical and demographic factors were compared between patients delivering at least 1 SGA infant and AGA pairs using Pearson's chi2 Student t test statistics and logistic regression. RESULTS: There were 11,827 twin pregnancies evaluated. Risk factors associated with SGA deliveries included tobacco abuse, poor weight gain, lean prepregnancy body mass index, African American race, and nonmarried. The logistic regression identified tobacco abuse as the single greatest risk for poor fetal growth, (odds ratio [OR] 1.95; 95% CI [1.68, 2.27]). Weight gain of less than one-half lb/wk also increased SGA risk (OR 1.35; 95% CI [1.16, 1.68]), whereas weight gain greater than 1 lb/wk decreased SGA risk (OR 0.77; 95% CI [0.68, 0.86]). CONCLUSION: Tobacco abuse and weight gain are the modifiable risk factors, which require intervention during a twin pregnancy. Patients should be encouraged to stop tobacco abuse and gain a minimum of one-half lb/wk in the later half of pregnancy to minimize the risk for growth restriction.     

Risk factors for preeclampsia in Japanese twin pregnancies: comparison with those in singleton pregnancies

Objective  To identify the factors associated with the increased risk of developing preeclampsia in twin pregnancies compared with those in singleton pregnancies. Methods  We reviewed the obstetric records of all deliveries at ≥22 weeks’ gestation managed at the Japanese Red Cross Katsushika Maternity Hospital between 2001 and 2007. Results  The incidence of preeclampsia in the twin pregnancies (7.6%: 45 in 593) was significantly higher than that in the singleton pregnancies (1.7%: 196 in 11,311; P < 0.01). In singleton pregnancies, the developing preeclampsia was associated with maternal age at ≥35 years, primiparity, maternal BMI ≥25 before pregnancy, history of infertility therapies such as IVF and having a history of previous preeclampsia. In twin pregnancies, however, the developing preeclampsia was not associated with these variables. Conclusions  In Japanese women, the factors reported to be associated with the increased risk of preeclampsia in singleton pregnancies may not alter the increased risk of preeclampsia in twin pregnancies.     

Outcomes of preterm premature rupture of membranes in twin pregnancies

Objective. To describe outcomes in twin pregnancies with preterm premature rupture of membranes (PPROM).

Methods. Dichorionic twin pregnancies complicated by PPROM at <34 weeks of gestation for the period 2003 to 2006 were identified. Outcomes were obtained through chart review. The relationship between gestational age at premature rupture of membranes (PROM), latency from PROM to delivery, and infection were examined.

Results. In 49 twin pregnancies, the median gestational age at PROM was 31 weeks with a median latency between PROM and delivery of 0 days (interquartile range 0–6). Latency intervals of ≥2 and ≥7 days were achieved by 40.8% and 22.4%, respectively. PPROM at <30 weeks was associated with significantly higher rates of latency of ≥ 2 days (70.6% vs. 25.0%) and ≥7 days (47.1% vs. 9.4%). There was a significant relationship between latency and clinical and histologic signs of infection.

Conclusions. After 30 weeks, most twin pregnancies with PPROM delivered within 2 days. Infection appears to be a consequence rather than a cause of PPROM in most cases.     

Outcomes of ultrasound-indicated cerclage in twin pregnancies with a short cervical length

ObjectiveTo investigate the outcomes of ultrasound-indicated cerclage in dichorionic-diamniotic (DCDA) twin pregnancies with a short cervical length.Materials and methodsThis was a retrospective cohort study of DCDA twin pregnancies with a short cervical length (≤25 mm) from January 2000 to July 2017 to compare maternal and neonatal outcomes. Additional sub-analysis was performed by dividing the patients into two subgroups by a cervical length ≤15 mm and between 16 and 25 mm.ResultsOne hundred and eight women were initially diagnosed with twin pregnancies and cervical insufficiency. After excluding cases not meeting the study criteria, 46 women were recruited for analysis, of whom 33 underwent ultrasound-indicated cerclage. The delivery age of the cerclage group was significantly later than the non-cerclage group (34.85 ± 3.91 versus 31.08 ± 5.25 weeks, p = 0.011), and the latency was significantly longer in the cerclage group than in the non-cerclage group (86.09 ± 41.32 versus 52.31 ± 33.24 days, p = 0.014). Sub-analysis revealed that these benefits were significant in the subgroup of a cervical length ≤15 mm. Both first twin (twin A) and second twin (twin B) had a significantly decreased rate of neonatal intensive care unit admission in the cerclage group. However, twin A had more promising outcomes with significantly decreased rates of neonatal respiratory distress syndrome (6.7% versus 50.0%, p = 0.004) and sepsis (0% versus 25.0%, p = 0.019).ConclusionUltrasound-indicated cerclage in DCDA twin pregnancies can decrease preterm birth and prolong the latency. It also decreases neonatal morbidity, and is especially beneficial for twin A.     

Amniocentesis in treatment of acute polyhydramniosis in twin pregnancies

A rare complication in twin pregnancy is acute polyhydramniosis. If left untreated, the perinatal mortality is 100%. The clinical courses of two cases treated with ultrasound-guided amniocentesis are presented. In the first case altogether 4875 ml amniotic fluid was drained. Both twins died within the first 24 hours of life after delivery in gestational week 26. In the second case 2150 ml amniotic fluid was drained. Both twins survived and were delivered in good condition in gestational week 35. We recommend ultrasound-guided amniocentesis to be performed in twin pregnancy affected by acute polyhydramniosis.     

单、双胎妊娠并发子痫前期不良妊娠结局的荟萃分析

目的探讨单、双胎妊娠并发子痫前期的孕妇与围产儿不良结局发病率差异。 方法检索PubMed、Web of Science、中国生物医学文献数据库、中国学术文献总库、万方和维普中文数据库中2000年1月至2017年12月国内外发表的关于单、双胎妊娠并发子痫前期妊娠结局的研究。采用RevMan 5.3与Stata 12.0软件对资料进行荟萃分析,采用OR值及相应的95%CI评价不良结局与双胎妊娠并发子痫前期的相关性。 结果纳入10篇文献,共692例双胎妊娠合并子痫前期,3101例单胎妊娠合并子痫前期。双胎妊娠合并子痫前期组发病率高于单胎妊娠合并子痫前期：胎盘早剥OR＝2.16,95%CI为1.40～3.36;产后出血OR＝2.90, 95%CI为2.03～4.15;心功能衰竭OR＝3.73, 95%CI为2.10～6.63 ;肺水肿OR＝2.76, 95%CI为1.04～7.27;剖宫产OR＝2.27, 95%CI为1.58～3.26;胎膜早破OR＝2.99, 95%CI为1.64～5.47;早产OR＝6.24,95%CI为4.16～9.38,新生儿重症监护病房转入率OR＝2.33, 95%CI为1.66～3.26。 结论双胎妊娠合并子痫前期的不良妊娠结局包括胎盘早剥、产后出血、心功能衰竭、肺水肿、剖宫产、胎膜早破、早产和新生儿重症监护病房转入的发病率比单胎妊娠合并子痫前期高。     

Determination of amniotic fluid volume in twin pregnancies: ultrasonographic evaluation versus operator estimation

OBJECTIVE: We sought to determine the accuracy of amniotic fluid volume estimation (visually) in diamniotic twin pregnancy versus ultrasonography techniques. STUDY DESIGN: In this prospective study the volume of each sac in 23 sets of diamniotic twin pregnancies was subjectively and objectively estimated by a second-year obstetric resident, nurse sonographer, maternal-fetal medicine fellow, and maternal-fetal medicine staff. The actual volume was confirmed by amniocentesis and a dye-dilution technique. RESULTS: There was no difference in the total number of correct estimates of volume by level of operator experience (P =.98), ultrasonography technique (P =.87), or combined subjective versus objective correct estimates (P =.87). Identification of low volume was not different among the four evaluators (P =.48), but the percentage of correct estimates was poor (7%-29%). The 2-diameter pocket was a better predictor of oligohydramnios (57%) than the amniotic fluid index or the largest vertical pocket (12.5%; P =.002). CONCLUSION: The extremes of volume (low or high) are poorly identified by the subjective or objective assessment of volume.     

Screening and prevention of preterm birth in twin pregnancies

Preterm birth (PTB) is commonest cause of perinatal mortality and morbidity in multiple pregnancies with significant long-term sequelae. The etiology of PTB is multifactorial. Universal screening by a transvaginal assessment of cervical length (CL) at midtrimester scan is recommended for all women with twin pregnancies. Women with CL ≤ 25 mm should be offered prophylactic vaginal progesterone to mitigate the risk of PTB. Other modalities like home uterine activity monitoring, digital cervical examination, fetal fibronectin (FFN) assessment, and screening for infections are not recommended. History-indicated cerclage is not advised in unselected twin pregnancies, but a combination of physical examination-indicated cerclage, tocolytics, and antibiotics may be considered in twin pregnancies with a dilated cervix prior to 24 weeks’ gestation. Routine use of cervical pessary is not advised and should be limited to research settings. Neither transvaginal CL nor FFN assessment is supported by evidence to predict the risk of PTB in symptomatic women with multiple pregnancies. More research is warranted to develop and validate algorithms to predict PTB to provide individualized care to these high-risk pregnancies.     

Intraamniotic Bleeding Following Transabdominal Amniocentesis

A prospective study on 231 consecutive patients who underwent transabdominal genetic amniocentesis was performed to determine the incidence of intraamniotic bleeding associated with needle removal and to determine if this increased future pregnancy complications. Eleven procedures traversed the placenta and intraamniotic bleeding was seen in every case. In 220 cases the placenta was not traversed and intraamniotic uterine wall bleeding was seen in 38%. In 92% of these, bleeding stopped in less than 30 sec. No difference in pregnancy outcome was seen between cases with visible bleeding when compared to cases where bleeding was not identified, suggesting that this is a normal but unavoidable aspect of amniocentesis. The location of the placenta was not a factor except that a transplacental procedure was more likely with an anterior placenta. Possible explanations for this unexpected high incidence are discussed as well as the theoretical concern over exposing the unborn fetus to maternal blood borne infections.     

Resting oxygen consumption in patients with twin pregnancy

Objective This study examined the resting oxygen consumption in patients with a twin pregnancy and compared the results with those of singleton pregnancies.Methods In 15 patients with a twin and 26 patients with a singleton pregnancy, the resting oxygen consumption was measured using an open-circuit ventilatory system during the third trimester of pregnancy.Results The average resting oxygen consumption in patients with a twin pregnancy was 231±25 ml/min, significantly higher than that in patients with a singleton pregnancy (209±24 ml/min, P<0.05).Conclusion Our results indicate an estimated increase in metabolic rate in patients during the third trimester of a twin pregnancy compared with those with a singleton pregnancy.     

Obstetrical and oncological outcomes of twin pregnancies with hydatidiform mole and coexisting fetus

ObjectiveTo evaluate the obstetrical and oncological progression of twin pregnancies with hydatidiform mole coexisting fetus (HMCF).Materials and methodsUsing a retrospective method based on patients from the Women's Hospital, Zhejiang University School of Medicine database between January 1990 and October 2020, 17 patients were histologically confirmed as having HMCF, and the patients' prenatal diagnosis, outcomes and development of gestational trophoblastic neoplasia (GTN) were reviewed.ResultsAmong these 17 cases, 11 (64.71%) cases were complete hydatidiform mole coexisting fetus (CHMCF), and 6 (35.29%) cases were partial hydatidiform mole coexisting fetus (PHMCF). The gestational age at diagnosis of CHMCF was significantly earlier than that of PHMCF [9 (8–24) vs. 18 (11–32) weeks, respectively, P < 0.05]. The live birth rate of PHMCF was slightly higher than that of CHMCF (33.33%; 18.18%), but this difference was not statistically significant. The overall rate of GTN incidence of HMCF was 47.06% (8/17), and the GTN rates of PHMCF and CHMCF were 33.33% (2/6) and 54.55% (6/11), respectively. There was no significant difference in the GTN rate between patients who chose to continue pregnancy and those who terminated pregnancy before 24 weeks of gestation. The GTN rate of patients with term delivery was not significantly higher than that of preterm delivery.ConclusionIn HMCF cases, the incidence rate of CHMCF was higher than that of PHMCF, and PHMCF is more difficult to diagnose in the early stage. Continuing pregnancy does not increase the risk of GTN compared to terminating pregnancy. In cases of HMCF, when the fetal karyotype is normal and maternal complications are controlled, it is safe to continue the pregnancy and extend it to term.     

Monochorionic monoamniotic twin pregnancies

Monochorionic monoamniotic (MCMA) twin pregnancy is rare and associated with increased complication rates when compared with singletons, dichorionic and monochorionic diamniotic pregnancy in general. Monoamnionicity presents an enormous challenge following its accurate diagnosis, where the absence of an inter-twin membrane subsequently results in cord entanglement and consistently fluctuating foetal position. Furthermore, the detection of twin-twin transfusion syndrome (TTTS) in MCMA pregnancy can be challenging in the absence of amniotic fluid volume discordance without the presence of the inter-twin dividing membrane. Early surveillance of foetal anatomy permits early recognition of foetal structural anomalies, the twin reversed arterial perfusion (TRAP) sequence and conjoined twins. However, the evidence on how best to monitor MCMA pregnancies remains inadequate, though observational studies have demonstrated that once surveillance is initiated, the potential risk of foetal death decreases significantly. In-utero foetal demise can be acute and unpredictable in MCMA pregnancies, despite close surveillance. Elective preterm delivery is usually advocated when the risk of foetal loss upon continuing the pregnancy outweighs the risk of prematurity – around 33 weeks’ gestation by caesarean section. Nevertheless, the optimal prenatal surveillance regimen and prompts for delivery have yet to be defined.     

Genetic diagnosis in multiple pregnancies: Amniocentesis versus chorionic villus sampling

The likelihood of finding chromosomal anomalies and Mendelian diseases is increased in multiple gestations compared to singletons. Prenatal diagnosis may therefore be indicated in multiple pregnancies at least as often as in singleton gestations. Invasive testing using amniocentesis or chorionic villus sampling has similar margins of safety. Chorionic villus sampling has a significant advantage over amniocentesis, because it offers rapid karyotyping and biochemical or DNA studies at an earlier stage of pregnancy. However, only experienced centers should perform these procedures, because of the technical aspects of the procedures as well as the expertise needed in the interpretation and handling of discordant results.     

Complete hydatidiform mole with coexistent live fetus in dichorionic twin gestation

Case report A 28-year-old patient gravida 3, para 2 was admitted at 16 weeks gestation with the diagnosis of complete hydatidiform mole with coexistent live fetus (CHMCF) in dichorionic twin gestation. The HCG level was 530,000 mIU/ml. The pregnancy was terminated by hysterotomy. Outcome Histopathologic analysis revealed a hydatidiform mole and a 17-week-old male fetus attached to the normal looking placenta by a double-vesseled cord. A final karyotype on cord blood samples confirmed normal 46 XY. Weekly performed serial HCG values showed declining trend and were undetectable by 10 weeks post delivery.     

双胎妊娠的分娩方式与妊娠结局探讨

目的　探讨双胎妊娠的分娩方式与妊娠结局的关系。方法　将 1995年 1月至 2 0 0 3年 5月 98例双胎妊娠产妇按分娩方式分为阴道分娩组及剖宫产组 ,对其临床资料进行回顾性分析。结果　两组的孕周、产后出血率比较差异无显著性意义 (P >0 0 5 ) ,剖宫产组新生儿体重显著高于阴道分娩组 (P <0 0 1) ,两组第 1胎分娩新生儿窒息率差异无显著性意义 (P >0 0 5 ) ,而第 2胎分娩新生儿窒息率剖宫产组显著低于阴道分娩组(P <0 0 5 )。结论　正确选择双胎妊娠的分娩方式 ,将有助于降低剖宫产率及新生儿窒息率