The influence of the introduction of a national prenatal screening program on late termination of pregnancy, a retrospective cohort study.

OBJECTIVE: To assess the influence of a national prenatal screening program on category 1 (lethal anomalies) late terminations of pregnancy (LTOP). METHODS: In this population-based retrospective cohort study, we included all category 1 LTOPs from 2004 to 2015 in the Netherlands. The number of LTOPs before and after the introduction of the program was compared as well as the diagnostic process and factors contributing to LTOP. RESULTS: In total, 97 LTOPs were reported. After the introduction of the program, the number of LTOPs decreased from 17 per year to 5 per year on average. The number of cases in which the diagnostic process started with obstetric indications decreased from 55% to 17% (p < 0.01) and the number of cases detected by routine screening increased from 11% to 52% (p < 0.01). Four factors still contributed to LTOP after the introduction of the screening program: diagnostic or parental delay (40%), absence of screening (24%), false negative results of prior screening (14%) and late onset of disease (12%). CONCLUSION: The number of LTOPs decreased after the introduction of the screening program. At present, the diagnostic process is mostly screening driven. Parental- and diagnostic delay is still an important factor that contributes to LTOP.

Early Detection of Isolated Severe Congenital Heart Defects Is Associated with a Lower Threshold to Terminate the Pregnancy.

INTRODUCTION: Early detection of isolated severe congenital heart defects (CHDs) allows extra time for chromosomal analysis and informed decision making, resulting in improved perinatal management and patient satisfaction. Therefore, the aim of this study was to assess the value of an additional first-trimester screening scan compared to only a second-trimester scan in fetuses diagnosed with isolated severe CHDs. Prenatal detection rate, time of prenatal diagnosis, and pregnancy outcome were evaluated in the Netherlands after implementation of a national screening program. MATERIALS AND METHODS: We performed a retrospective geographical cohort study and included 264 pre- and postnatally diagnosed isolated severe CHD cases between January 1, 2007, and December 31, 2015, in the Amsterdam region. Severe CHD was defined as potentially life threatening if intervention within the first year of life was required. Two groups were defined: those with a first- and second-trimester anomaly scan (group 1) and those with a second-trimester anomaly scan only (group 2). A first-trimester scan was defined as a scan between 11 + 0 and 13 + 6 weeks of gestation. RESULTS: Overall, the prenatal detection rate for isolated severe CHDs was 65%; 63% were detected before 24 weeks of gestation (97% of all prenatally detected CHDs). Prenatal detection rate was 70.2% in the group with a first- and second-trimester scan (group 1) and 58% in the group with a second-trimester scan only (group 2) (p < 0.05). Median gestational age at detection was 19 + 6 (interquartile range [IQR] 15 + 4 - 20 + 5) in group 1 versus 20 + 3 (IQR: 20 + 0 - 21 + 1) in group 2 (p < 0.001). In group 1, 22% were diagnosed before 18 weeks of gestation. Termination of pregnancy rate in group 1 and group 2 were 48% and 27%, respectively (p < 0.01). Median gestational age at termination did not differ between the two groups. CONCLUSION: Prenatal detection rate of isolated severe CHDs and termination of pregnancy rate was higher in the group with both a first- and second-trimester scan. We found no differences between timing of terminations. The additional time after diagnosis allows for additional genetic testing and optimal counseling of expectant parents regarding prognosis and perinatal management, so that well-informed decisions can be made.

Uniform International Method to Measure Cervical Length: Are We There Yet?

INTRODUCTION: Cervical length is an important predictor of spontaneous preterm birth. So far, the best way to measure cervical length has not been established. We aimed to compare the incidence of short cervical length between three methods of cervical length measurement with and without the inclusion of cervico-isthmic complex (CIC) (six methods in total) and to determine the positive predictive value for spontaneous preterm birth. MATERIAL AND METHODS: We performed a prospective single-center cohort study in women with a singleton pregnancy between August 2014 and December 2018. During the routine fetal anomaly scan (18-22 weeks), women were offered transvaginal ultrasound for cervical length measurement to screen for the risk of spontaneous preterm birth. Each cervix was measured in six different ways: single-line, two-line, and tracing method between the internal and external os of the cervix with and without CIC. We evaluated the predictive value of the different measurements for spontaneous delivery before 37 weeks using positive predictive values. RESULTS: Our final study population comprised 1,691 women. The overall rate of preterm birth <37 weeks was 8.0% (4.6% spontaneous, 3.4% iatrogenic preterm birth). The mean gestational age at cervical length measurement was 19+6 weeks. The different measuring techniques resulted in significant different cervical lengths, showing a maximum difference of >8 mm between the techniques (41.04 mm [SD 7.1] with one-line without CIC and 49.18 [SD 9.05] mm with trace with CIC) with an incidence of short cervical length below <25 mm ranging from 0.4% to 1.1% (p = 0.18). The positive predictive values for spontaneous preterm birth <37 weeks ranged from 42.9% to 20.0%. CONCLUSION: Different measurement methods for cervical length resulted in statistically significant differences in measured cervical length. Depending on the chosen cut-off this translates to different incidences of short cervical length and influences the number of women designated as high risk for preterm birth and receiving treatment. For interpretation and comparability between (inter-) national studies, it is important to adequately report on the employed technique. Future research should focus on determining the optimal measuring technique and a universal method of measurement.

Prenatal sonographic features can accurately determine parental origin in triploid pregnancies.

OBJECTIVE: To describe the prenatal sonographic features and maternal biochemical markers in triploid pregnancies and to assess whether prenatal phenotype can determine genetic origin. METHODS: We performed a retrospective multicenter cohort study that included all triploid pregnancies diagnosed between 2000 and 2018 in two Fetal Medicine Units in Amsterdam. Fetal growth, presence of structural anomalies, extra-fetal anomalies, and maternal biochemical markers were retrieved. Asymmetrical intrauterine growth restriction was diagnosed when the head-to-abdominal circumference (HC/AC) ratio was >95th centile. Parental origin was analyzed via molecular genotyping in 46 cases (38.3%). RESULTS: One hundred and twenty triploid pregnancies were identified, of which 86 cases (71.6%) were detected before 18 weeks of gestation. Triploidy of maternal origin was found in 32 cases (69.6%) and was associated with asymmetrical growth restriction, a thin placenta, and low pregnancy-associated plasma protein A and free beta-human chorionic gonadotrophin (ß-hCG) levels. Triploidy of paternal origin was found in 14 cases (30.4%) and was associated with an increased nuchal translucency, placental molar changes, and a high free ß-hCG. Prospective prediction of the parental origin of the triploidy was made in 30 of the 46 cases based on phenotypical ultrasound presentation, and it was correct in all cases. CONCLUSION: Asymmetrical growth restriction with severe HC/AC discrepancy is pathognomonic of maternal triploidy. Placental molar changes indicate a paternal triploidy. Moreover, triploidy can present with an abnormal first trimester combined test, with serum levels on the extreme end. When available results of maternal serum markers can support the diagnosis of parental origin of the triploidy, an accurate assessment of the parental origin based on prenatal sonographic features is possible, making DNA analysis redundant.

The capacity of mid-pregnancy cervical length to predict preterm birth in low-risk women: a national cohort study.

INTRODUCTION: We investigated the predictive capacity of mid-trimester cervical length (CL) measurement for spontaneous and iatrogenic preterm birth. MATERIAL AND METHODS: We performed a prospective observational cohort study in nulliparous women and low-risk multiparous women with a singleton pregnancy between 16(+0) and 21(+6) weeks of gestation. We assessed the prognostic capacity of transvaginally measured mid-trimester CL for spontaneous and iatrogenic preterm birth (<37 weeks) using likelihood ratios (LR) and receiver-operating-characteristic analysis. We calculated numbers needed to screen to prevent one preterm birth assuming different treatment effects. Main outcome measures were preterm birth <32, <34 and <37 weeks. RESULTS: We studied 11,943 women, of whom 666 (5.6%) delivered preterm: 464 (3.9%) spontaneous and 202 (1.7%) iatrogenic. Mean CL was 44.1 mm (SD 7.8 mm). In nulliparous women, the LRs for spontaneous preterm birth varied between 27 (95% CI 7.7-95) for a CL ≤ 20 mm, and 2.0 (95% CI 1.6-2.5) for a CL between 30 and 35 mm. For low-risk multiparous women, these LRs were 37 (95% CI 7.5-182) and 1.5 (95% CI 0.97-2.2), respectively. Using a cut-off for CL ≤ 30 mm, 28 (6.0%) of 464 women with spontaneous preterm birth were identified. The number needed to screen to prevent one case of preterm birth was 618 in nulliparous women and 1417 for low-risk multiparous women (40% treatment effect, cut-off 30 mm). CONCLUSION: In women at low risk of preterm birth, CL predicts spontaneous preterm birth. However, its isolated use as a screening tool has limited value due to low sensitivity.