Expression of dNK cells and their cytokines in twin pregnancies with preeclampsia.

OBJECTIVES: To assess the expression of decidual natural killer (dNK) cells and their cytokines in twin pregnancies with preeclampsia. METHODS: This was a prospective case-control study. The inclusion criteria were diamniotic (monochorionic or dichorionic) twin pregnancies in the third trimester with negative serological results for infectious diseases; absence of major fetal abnormalities or twin-twin transfusion syndrome; and no history of administration of corticosteroids in this pregnancy. The control group (CG) included uncomplicated twin pregnancies, and the preeclampsia group (PEG) included twin gestations with clinical and laboratory confirmation of the disease according to well-established criteria. Samples of the decidua were obtained and analyzed by immunohistochemistry for the expression of dNK cells and interleukins (ILs) 10, 12 and 15. In addition, maternal serum samples were collected to determine the levels of these interleukins. RESULTS: Thirty twin pregnancies were selected: 20 in the control group (CG) and 10 in the preeclampsia group (PEG). The PEG showed strong placental immunostaining for IL-15 (p=0.001) and high maternal serum levels of IL-10 (22.7 vs. 11.9 pg/mL, p=0.024) and IL-15 (15.9 vs. 7.4 pg/mL, p=0.024). CONCLUSION: A higher maternal serum concentration of both pro- and anti-inflammatory factors was observed in the twin pregnancies in the PEG. However, no difference in placental expression of IL-10 was found between the groups. These findings may suggest that maternal attempts to balance these interleukins were not sufficient to cause a placental response, and this failure may contribute to the development of preeclampsia.

Late neurological deficit after attempted PICC insertion in the arm.

INTRODUCTION:: Insertion of central catheters in peripheral vessels is a common procedure performed for a variety of indications, including parenteral nutrition. Hyperemesis gravidarum may require parenteral nutrition in exceptional situations. Although globally safe, insertion of peripherally inserted central catheters (PICCs) can lead to complications. CASE REPORT:: We describe a case of a pregnant woman who required parenteral nutrition and underwent an unsuccessful PICC insertion attempt resulting in arterial puncture, and who 34 days later presented with right upper limb paresthesia. A pseudoaneurysm with nerve compression was diagnosed and treated by open surgery, without maternal or fetal complications. CONCLUSION:: We recommend active surveillance ultrasound (e.g. in the first 24-48 h) of unsuccessful PICC insertion attempts, because late complications may occur and require invasive procedures for treatment.

Expression of dNK cells and their cytokines in twin pregnancies with preeclampsia

OBJECTIVES: To assess the expression of decidual natural killer (dNK) cells and their cytokines in twin pregnancies with preeclampsia. METHODS: This was a prospective case-control study. The inclusion criteria were diamniotic (monochorionic or dichorionic) twin pregnancies in the third trimester with negative serological results for infectious diseases; absence of major fetal abnormalities or twin-twin transfusion syndrome; and no history of administration of corticosteroids in this pregnancy. The control group (CG) included uncomplicated twin pregnancies, and the preeclampsia group (PEG) included twin gestations with clinical and laboratory confirmation of the disease according to well-established criteria. Samples of the decidua were obtained and analyzed by immunohistochemistry for the expression of dNK cells and interleukins (ILs) 10, 12 and 15. In addition, maternal serum samples were collected to determine the levels of these interleukins. RESULTS: Thirty twin pregnancies were selected: 20 in the control group (CG) and 10 in the preeclampsia group (PEG). The PEG showed strong placental immunostaining for IL-15 (p=0.001) and high maternal serum levels of IL-10 (22.7 vs. 11.9 pg/mL, p=0.024) and IL-15 (15.9 vs. 7.4 pg/mL, p=0.024). CONCLUSION: A higher maternal serum concentration of both pro- and anti-inflammatory factors was observed in the twin pregnancies in the PEG. However, no difference in placental expression of IL-10 was found between the groups. These findings may suggest that maternal attempts to balance these interleukins were not sufficient to cause a placental response, and this failure may contribute to the development of preeclampsia.

Prenatal administration of vaginal progesterone and frequency of uterine contractions in asymptomatic twin pregnancies.

INTRODUCTION: A previous study indicated that progesterone reduces the mean uterine contraction frequency in singleton pregnancy at high risk for preterm birth. The aim of this study was to investigate the effect of vaginal progesterone on the frequency of uterine contractions in twin pregnancies. MATERIAL AND METHODS: This was a secondary analysis of a randomized, double-blind, placebo-controlled trial of twin pregnancies exposed to vaginal progesterone or placebo. Naturally conceived twin pregnancies with no prior history of preterm delivery, asymptomatic regarding preterm labor, who had undergone uterine contraction frequency monitoring from 24 to 34 weeks and 6 days were included in the study. Comparison of the mean frequency of uterine contractions between the treatment groups was performed. We also examined the influence of cervical length and chorionicity on the mean frequency of uterine contractions according to the group. RESULTS: The final analysis included 166 women in the progesterone and 170 in the placebo group. The baseline characteristics were similar in the two groups. Overall, no difference in the mean frequency of uterine contractions (p = 0.91) was observed between the progesterone (2.54 ± 3.19) and placebo (2.56 ± 3.59) groups. Also, no difference in the mean frequency of uterine contractions was observed between the groups in each week between 24 and 34 weeks and 6 days of gestation. Cervical length and chorionicity did not influence the frequency of contractions according to the progesterone or placebo treatment. CONCLUSIONS: Overall, progesterone does not influence the frequency of uterine contractions in twin pregnancies.

Prediction of perinatal mortality in triplet pregnancies.

PURPOSE: To investigate predictors of perinatal mortality in triplet pregnancies. METHODS: Retrospective cohort managed in a tertiary teaching hospital (1998-2012) including all pregnancies with tree live fetuses at the first ultrasound examination, performed after 11 weeks of gestation. Primary end-point was defined as the number of children alive at hospital discharge. Ordinal stepwise regression analysis examined the association with maternal age, parity, pregnancy chorionicity, gestational age at our first ultrasound evaluation, presence of maternal clinical, obstetrical and fetal complications and gestational age at delivery. RESULTS: Sixty-seven triplet pregnancies were first seen at 18.5 ± 6.8 weeks, 33 (49.3 %) were trichorionic, obstetric complications occurred in 34 (50.7 %) and fetal complications were diagnosed in 17 (25.4 %). Perinatal mortality rate was 249 ‰ (95 % CI 189-317) and 138 (73 %) children were discharged alive from hospital (11 pregnancies with no survivors; single and double survival in ten cases each; all children alive in 36). Regression analysis showed that presence of fetal complications (OR 0.10, 95 % CI 0.03-0.36) and gestational age at delivery (OR 1.55, 95 % CI 1.31-1.85) are significant predictors of outcome (p < 0.001). CONCLUSIONS: Perinatal mortality in non-selected triplet pregnancies is high and is related to the presence of fetal complications and gestational age at delivery.

Vaginal progesterone for the prevention of preterm birth in twin gestations: a randomized placebo-controlled double-blind study.

OBJECTIVE: The purpose of this study was to investigate the use of vaginal progesterone for the prevention of preterm delivery in twin pregnancies. STUDY DESIGN: We conducted a prospective, randomized, double-blind, placebo-controlled trial that involved 390 naturally conceived twin pregnancies among mothers with no history of preterm delivery who were receiving antenatal care at a single center. Women with twin pregnancies between 18 and 21 weeks and 6 days' gestation were assigned randomly to daily vaginal progesterone (200 mg) or placebo ovules until 34 weeks and 6 days' gestation. The primary outcome was the difference in mean gestational age at delivery; the secondary outcomes were the rate of spontaneous delivery at <34 weeks' gestation and the rate of neonatal composite morbidity and mortality in the treatment and nontreatment groups. RESULTS: The baseline characteristics were similar in both groups. The final analysis included 189 women in the progesterone group and 191 in the placebo group. No difference (P = .095) in the mean gestational age at delivery was observed between progesterone (35.08 ± 3.19 [SD]) and placebo groups (35.55 ± 2.85). The incidence of spontaneous delivery at <34 weeks' gestation was 18.5% in the progesterone group and 14.6% in the placebo group (odds ratio, 1.32; 95% confidence interval, 0.24-2.37). No difference in the composite neonatal morbidity and mortality was observed between the progesterone (15.5%) and placebo (15.9%) groups (odds ratio, 1.01; 95% confidence interval, 0.58-1.75). CONCLUSION: In nonselected twin pregnancies, vaginal progesterone administration does not prevent preterm delivery and does not reduce neonatal morbidity and death.

Fetal Growth Pattern and Prediction of Low Birth Weight in Gastroschisis.

OBJECTIVES: To examine growth patterns and predictions of low birth weight in gastroschisis fetuses. METHODS: This is a retrospective study of isolated fetal gastroschisis before week 24. Ultrasound fetal biometric parameters - head circumference (HC), abdominal circumference (AC), femur length, HC/AC ratio and estimated fetal weight (EFW)--were plotted against normal growth charts. The percentage difference in mean values between normal and gastroschisis fetuses was determined. The growth deficit for each ultrasound parameter was calculated for the fetuses with 1 examination in each designated period (period I: weeks 20-25(+6); period II: weeks 26-31(+6); period III: from week 32 until term). For low birth weight prediction, measurements below the 10th percentile in periods I and II were tested. RESULTS: Seventy pregnancies were examined. For all fetal parameters, the mean measurements were lower in fetuses with gastroschisis (p < 0.005). The EFW revealed an increased growth deficit between the periods (p = 0.030). HC was predictive of low birth weight in period II (OR = 6.07; sensitivity = 70.8%; specificity = 71.4%). CONCLUSIONS: Fetuses with gastroschisis present a reduced growth pattern, and it appears that no growth recovery occurs after the growth restriction has been established. Between week 26 and week 31(+6), an HC measurement below the 10th percentile is associated with an increased risk of low birth weight.

Transplacental total IgG transfer in twin pregnancies.

PROBLEM: In twin pregnancies, factors that influence total umbilical cord IgG concentration and IgG transfer ratio are not well known. METHOD: Blood samples were prospectively collected from 57 twin pregnancies. Stepwise multivariate regression analysis was used to evaluate the association between total IgG levels in the umbilical cord blood and IgG transfer ratio according to serum IgG concentration, pregnancy chorionicity, the presence of abnormal umbilical artery pulsatility index, intrauterine growth restriction, gestational age at delivery (GAD), birthweight, and placental weight. RESULTS: Umbilical cord IgG concentration showed a positive correlation with serum IgG concentration and GAD; levels were significantly lower in monochorionic compared with dichorionic pregnancies. IgG transfer ratio also increased with GAD but was inversely correlated with serum IgG concentration levels. CONCLUSION: In twin pregnancies, besides serum IgG concentration and GAD, chorionicity also influences umbilical cord IgG concentration. Monochorionic twins have lower IgG cord concentration than dichorionic twins.

Prediction of intrauterine death and severe preterm delivery in twin pregnancies discordant for major fetal abnormality.

OBJECTIVE: To investigate predictors of spontaneous fetal death and preterm delivery in twin pregnancies with one fetus affected by a major structural malformation. STUDY DESIGN: Retrospective study (1999-2012) conducted at a tertiary teaching hospital involving 51 twin pregnancies (dichorionic=31, monochorionic diamniotic=15, monochorionic monoamniotic=4, not established=1) with a major fetal abnormality, enrolled before 26 weeks and managed expectantly. PRIMARY OUTCOMES: spontaneous fetal death, and/or delivery before 32 weeks. Prediction was examined with stepwise logistic regression analysis, and independent variables included: maternal age, gestational age at diagnosis, chorionicity, fetal gender, number and type of fetal abnormalities. Significance level was set at 0.15. RESULTS: Fetal abnormalities were diagnosed at a mean gestation of 21.5±3.7 weeks: cardiac abnormalities were observed in 31.4% of abnormal fetuses, abdominal wall defects in 29.4%, central nervous system 21.5%, spine 17.6%, effusions 17.6%, noncardiac thoracic abnormalities 15.7%, genital and urinary system 13.7%, limbs and soft tissue 3.9%, intestinal 1.9% and facial defects 1.9%. Fetal death occurred in 15 (29.4%) abnormal fetuses and was significantly correlated with the number of fetal malformations (p=0.02, OR=2.54, 95% CI=1.14-5.62), presence of effusion/hydrops (p=0.06, OR=4.7, 95% CI=0.95-24) and monochorionic placenta (p=0.11, OR=2.8, 95% CI=0.78-9.8). Normal co-twin fetal death occurred in four cases (7.8%) and was related to monochorionic pregnancies (p=0.14, OR=5.8, 95% CI=0.56-61). Delivery before 32 weeks was observed in 14 (27.5%) pregnancies and was related to presence of effusion/hydrops (p=0.04, OR=5.5, 95% CI=1.07-28). CONCLUSION: Spontaneous fetal death and/or delivery before 32 weeks in twin pregnancies with one fetus affected by a major structural malformation are related to the number of abnormalities diagnosed and presence of fetal effusion or hydrops.

Should we measure fetal omphalocele diameter for prediction of perinatal outcome?

OBJECTIVE: To evaluate the fetal omphalocele diameter/abdominal circumference ratio (OD/AC) as a predictor of adverse perinatal outcome. METHODS: Analysis involving 47 singleton pregnancies with fetal omphalocele, normal karyotype and absence of other major abnormalities. The OD/AC ratio was determined antenatally by ultrasound and the best cutoff for the prediction of neonatal death was determined by receiver operating characteristic curve analysis. Additional secondary outcomes included need for oral intubation in the first 24 h of life, two-step surgery or use of synthetic mesh, reoperation, parenteral feeding and need for respiratory assistance >21 days, time to first oral feed, and time to hospital discharge. RESULTS: Fetal OD/AC did not change significantly with gestational age. Postnatal death occurred in 10 (21.3%) cases and the best cutoff for prediction was an OD/AC ratio ≥0.26. In pregnancies with the first ultrasound evaluation performed before 31 weeks' gestation and an OD/AC ≥0.26, the likelihood ratio for needing intubation in the first 24 h of life was 2.6 (95% CI: 1.2-5.7), needing two-step surgery or use of mesh was 4.9 (95% CI: 1.9-14.4), and postnatal death was 4 (95% CI: 1.9-7.5). CONCLUSION: A fetal ultrasound OD/AC ratio ≥0.26 is associated with increased postnatal morbidity and mortality.

Twenty-five years of fetal echocardiography in conjoined twins: lessons learned.

BACKGROUND: The aim of this study was to determine the accuracy of prenatal echocardiography in the diagnosis of intracardiac malformations and the degree of cardiac fusion in conjoined twins presenting to a single center over a 25-year period. METHODS: The study group included 53 sets of conjoined twins from 1987 to 2012, including 38 thoracopagus, six parapagus, six omphalo-ischiopagus, two omphalopagus, and one cephalopagus. Twins were classified according to the degree of cardiac fusion: separate hearts and pericardium (group A, n = 10), separated hearts and common pericardium (group B, n = 2), fused atria and separated ventricles (group C, n = 2), and fused atria and ventricles (group D, n = 39). Postmortem examination was possible in 68 individual cases (98 deaths [69.3%]). RESULTS: Cardiac defects were diagnosed in 47 sets of twins (88.6%). In 10 (18.8%), only one fetus was affected, and in 37 (69.8%), both fetuses were affected (n = 84/106 [79.2%]). There was a high predominance of right-sided lesions (63.0% [53 fetuses in 84 affected]) including pulmonary atresia or stenosis (35.7%), tricuspid atresia (11.9%), and hypoplastic or small right ventricle (21.4%). Autopsy findings added information to fetal echocardiographic findings in nine sets of twins (25.7%). Three pairs classified antenatally in groups A, B, and D were confirmed by autopsy in groups B, C, and C, respectively. CONCLUSIONS: This study demonstrates that specialized fetal echocardiography is not a perfect diagnostic tool but is sensitive enough to establish prognosis in the counseling process. Because of complexity, such evaluations should be performed only at tertiary centers by specialists who are familiar with the peculiarities of this rare malformation. The predominance of right-sided lesions is not only an interesting finding, but this information has essential importance in terms of shortening examination times, allowing a more focused analysis of the fetal heart.

Computerized cardiotocography in pregnancies complicated by maternal asthma.

OBJECTIVE: The aim of the present study was to investigate the FHR parameters in term pregnancies complicated by asthma. STUDY DESIGN: prospective cross-sectional study performed between July 2008 and November 2009. Twenty-one singleton pregnancy between 36 and 40 weeks gestation with diagnosis of maternal asthma and no current use of oral corticosteroids were compared with 30 pregnancies without morbidities at the same gestational age. The computerized cardiotocography (System 8002, Sonicaid) was performed and 30 min analysis was studied. Statistical analysis included Student's t-test or Mann-Whitney U test for comparisons between groups. Categorical data were compared using the χ(2)-test or Fisher's exact test. RESULTS: There were no significant differences in FHR parameters analyzed by computerized cardiotocography: basal FHR (p = 0.80), number of accelerations >10 bpm (p = 0.08) or > 15 bpm (p = 0.20), duration of high episodes (p = 0.70), duration of low episodes (p = 0.46) and STV (p = 0.66). Asthmatic mothers presented mean number of fetal movement per hour significantly lower than control group (34.6 ± 28.2 vs. 60.6 ± 43.1, p = 0.02). CONCLUSION: Computerized cardiotocography demonstrates no association between the abnormal parameters of FHR and maternal asthma in term pregnancies. Maternal asthma was associated with less fetal movements per hour, suggesting further studies on the counting of fetal movements in pregnant women with asthma.

Feelings of women regarding end-of-life decision making after ultrasound diagnosis of a lethal fetal malformation.

OBJECTIVE: this study investigated the feelings of women regarding end-of-life decision making after ultrasound diagnosis of a lethal fetal malformation. The aim of this study was to present the decision making process of women that chose for pregnancy termination and to present selected speeches of women about their feelings. DESIGN: open psychological interviews conducted by a psychologist immediately after the diagnosis of fetal malformation by ultrasound. Analysis of the results was performed through a content analysis technique. SETTING: the study was carried out at a public university hospital in Brazil. PARTICIPANTS: 249 pregnant women who had received the diagnosis of a severe lethal fetal malformation. FINDINGS: fetal anencephaly was the most frequent anomaly detected in 135 cases (54.3%). Termination of pregnancy was decided by 172 (69.1%) patients and legally authorised by the judiciary (66%). The reason for asking for termination was to reduce suffering in all of them. In the 77 women who chose not to terminate pregnancy (30.9%), the reasons were related to feelings of guilt (74%). KEY CONCLUSIONS: the results support the importance of psychological counselling for couples when lethal fetal malformation is diagnosed. The act of reviewing moral and cultural values and elements of the unconscious provides assurance in the decision-making process and mitigates the risk of emotional trauma and guilt that can continue long after the pregnancy is terminated.

Gender-specific differences in fetal cardiac troponin T in pregnancies complicated by placental insufficiency.

BACKGROUND: Placental insufficiency and fetal growth restriction may lead to fetal hypoxia and acidemia, which result in fetal cardiac injury. OBJECTIVE: The goal of this study was to compare the levels of fetal cardiac troponin T (cTnT) at birth and fetal Doppler parameters according to fetal gender in pregnancies complicated by placental insufficiency before 34 weeks' gestation. METHODS: Between March 2007 and November 2010, singleton pregnancies with placental insufficiency characterized by abnormal umbilical artery Doppler results were prospectively studied. All the patients delivered by cesarean section, and Doppler examinations were performed up to 48 hours before birth. Immediately after delivery, umbilical artery blood samples were obtained for fetal cTnT measurements. RESULTS: Fifty high-risk pregnant women met the study criteria. The study groups were as follows: group 1 consisted of 23 male fetuses (46%) and group 2 consisted of 27 female fetuses (54%). cTnT levels were significantly higher in the group of male fetuses (median, 0.14; range, 0.01-0.85) compared with the group of female fetuses (median, 0.05; range, 0.01-0.27) (P = 0.039). In the group of male fetuses, Doppler results of the ductus venosus assessment revealed values of pulsatility index for veins ≥1.0 in 15 male fetuses (65.2%) and 9 female fetuses (33.3%) (P = 0.032). CONCLUSIONS: Fetal gender was associated with cTnT level at birth in pregnancies complicated by placental insufficiency before 34 weeks' gestation, although the Doppler findings did not support gender differences. The fetal cardiac compromise and cardiac injury may be influenced by fetal gender, suggesting differences in the cardiovascular response to fetal hypoxia.

Changes in amniotic fluid index after maternal oral hydration in pregnancies with fetal gastroschisis: initial observations.

OBJECTIVE: To evaluate the effect of maternal oral hydration on amniotic fluid index (AFI) in pregnancies with fetal gastroschisis. METHODS: AFI was evaluated at 24-hour intervals, during 4 consecutive days, under a continuous maternal oral water hydration regimen, in singleton pregnancies with isolated fetal gastroschisis. RESULTS: Nine pregnancies were examined at a mean gestational age of 31.6 weeks (+/-1.4) and mean maternal daily oral water intake was 3,437 (+/-810) ml. Mean AFI on days 0-3 were 13.2 (+/-2.9), 14.8 (+/-3.3), 14.5 (+/-3.1) and 14.8 (+/-2.6), respectively. AFI on day 0 was significantly lower compared to all the other 3 days (p = 0.01 and 0.02). Significant correlation was found in relative difference in AFI between day 0 and day 1 and gestational age (r = -0.67, p = 0.05) and the amount of water intake in the previous 24 h (r = 0.76, p = 0.02). CONCLUSION: Maternal oral water hydration significantly increases AFI in pregnancies with isolated fetal gastroschisis.

Utilização de técnicas de reprodução assistida e resultados perinatais / Use of assisted reproduction technologies and perinatal outcome

Nos ultimos anos, cada vez mais se tem difundido as técnicas de reprodução assistida e seu uso. A sua relação com malformações fetais e outras alterações em crianças geradas por estas técnicas têm sido objeto de grande discussão. Através da análise da literatura dos últimos 15 anos foi possível observar que os estudos parecem demonstrar um aumento da frequência de malformações urinárias em meninos concebidos por TRA e novos pontos de discussão têm sido levantados como risco de neoplasias, defeitos de imprinting gênico, alterações do desenvolvimento neuropsicomotor e até questionamentos com relação à fertilidade futura destas crianças. São necessários ainda novos estudos abrangendo casuísticas mais extensas e um seguimento a médio e longo prazo destas crianças.

A comparison between middle cerebral artery peak systolic velocity and amniotic fluid optical density at 450 nm in the prediction of fetal anemia.

OBJECTIVE: The purpose of this study was to compare fetal middle cerebral artery peak systolic velocity with amniotic fluid delta optical density at 450 nm in the prediction of fetal anemia. STUDY DESIGN: A prospective study that involved 28 singleton pregnancies that were at-risk for fetal anemia was carried out in a tertiary teaching hospital. Middle cerebral artery peak systolic velocity was measured immediately before the determination of deltaoptical density at 450 nm and fetal hemoglobin concentration. Sensitivities and predictive values for fetal anemia were examined. RESULTS: Fetal hemoglobin concentrations correlated significantly with middle cerebral artery peak systolic velocity (correlation coefficient, -0.77; P <.0001) and deltaoptical density at 450 nm zones (correlation coefficient, -0.56; P =.0025). Middle cerebral artery peak systolic velocity was >1.5 multiples of the median in 15 of 28 cases (54%); for this cutoff value, the sensitivity and positive-predictive values for a hemoglobin deficit of >-3SD were 75% and 60% and for a hemoglobin deficit of >-5SD were 100% and 47%, respectively. The corresponding values for deltaoptical density at 450-nm zone III (6/28 cases, 21%) were 0% (hemoglobin deficit, <-3SD) and 86% and 100% (hemoglobin deficit, <-5SD). CONCLUSION: Middle cerebral artery peak systolic velocity and amniotic fluid optical density at 450 nm are both useful in the prediction of fetal anemia. However, Doppler examination has the advantage of being a noninvasive method that can help reduce the number of invasive procedures in pregnancies that are at-risk for fetal anemia.

Reference range for cervical length in twin pregnancies.

BACKGROUND: Twin pregnancies are at increased risk of preterm delivery, and cervical length measurement by transvaginal ultrasound examination has been shown to be an effective method of screening for this complication. The aim of the present study is to establish a reference range for cervical length measurement throughout gestation in twin pregnancies. METHODS: Prospective study involving 144 nonselected twin pregnancies that delivered after 34 weeks and underwent ultrasound examination every 4 weeks for transvaginal measurement of cervical length. Mean cervical length measurements, 95% confidence intervals for the estimate and 95% prediction intervals were established throughout gestation by linear regression analysis. RESULTS: There was a significant correlation between cervical length measurements and gestational age [cervical length (mm) = - 0.758 * gestation age (weeks) + 56.69, r=- 0.43, p < 0.0001], and mean cervical length shortened by approximately 0.8 mm per week, from 47 mm at 13 weeks to 32 mm at 32 weeks. The corresponding lower limits for the 95% prediction intervals were 29 and 15 mm, respectively. CONCLUSION: Cervical length shortens gradually throughout gestation in twin pregnancies.