Vaginal progesterone for preventing preterm birth and adverse perinatal outcomes in twin gestations: a systematic review and meta-analysis

OBJECTIVE

To evaluate the efficacy of vaginal progesterone for the prevention of preterm birth and adverse perinatal outcomes in twin gestations.

DATA SOURCES

MEDLINE, Embase, LILACS, and CINAHL (from their inception to January 31, 2023), Cochrane databases, Google Scholar, bibliographies, and conference proceedings.

STUDY ELIGIBILITY CRITERIA

Randomized controlled trials that compared vaginal progesterone to placebo or no treatment in asymptomatic women with a twin gestation.

METHODS

The systematic review was conducted according to the Cochrane Handbook for Systematic Reviews of Interventions. The primary outcome was preterm birth <34 weeks of gestation. Secondary outcomes included adverse perinatal outcomes. Pooled relative risks with 95% confidence intervals were calculated. We assessed the risk of bias in each included study, heterogeneity, publication bias, and quality of evidence, and performed subgroup and sensitivity analyses.

RESULTS

Eleven studies (3401 women and 6802 fetuses/infants) fulfilled the inclusion criteria. Among all twin gestations, there were no significant differences between the vaginal progesterone and placebo or no treatment groups in the risk of preterm birth <34 weeks (relative risk, 0.99; 95% confidence interval, 0.84-1.17; high-quality evidence), <37 weeks (relative risk, 0.99; 95% confidence interval, 0.92-1.06; high-quality evidence), and <28 weeks (relative risk, 1.00; 95% confidence interval, 0.64-1.55; moderate-quality evidence), and spontaneous preterm birth <34 weeks of gestation (relative risk, 0.97; 95% confidence interval, 0.80-1.18; high-quality evidence). Vaginal progesterone had no significant effect on any of the perinatal outcomes evaluated. Subgroup analyses showed that there was no evidence of a different effect of vaginal progesterone on preterm birth <34 weeks of gestation related to chorionicity, type of conception, history of spontaneous preterm birth, daily dose of vaginal progesterone, and gestational age at initiation of treatment. The frequencies of preterm birth <37, <34, <32, <30, and <28 weeks of gestation and adverse perinatal outcomes did not significantly differ between the vaginal progesterone and placebo or no treatment groups in unselected twin gestations (8 studies; 3274 women and 6548 fetuses/infants). Among twin gestations with a transvaginal sonographic cervical length <30 mm (6 studies; 306 women and 612 fetuses/infants), vaginal progesterone was associated with a significant decrease in the risk of preterm birth occurring at <28 to <32 gestational weeks (relative risks, 0.48-0.65; moderate- to high-quality evidence), neonatal death (relative risk, 0.32; 95% confidence interval, 0.11-0.92; moderate-quality evidence), and birthweight <1500 g (relative risk, 0.60; 95% confidence interval, 0.39-0.88; high-quality evidence). Vaginal progesterone significantly reduced the risk of preterm birth occurring at <28 to <34 gestational weeks (relative risks, 0.41-0.68), composite neonatal morbidity and mortality (relative risk, 0.59; 95% confidence interval, 0.33-0.98), and birthweight <1500 g (relative risk, 0.55; 95% confidence interval, 0.33-0.94) in twin gestations with a transvaginal sonographic cervical length ≤25 mm (6 studies; 95 women and 190 fetuses/infants). The quality of evidence was moderate for all these outcomes.

CONCLUSION

Vaginal progesterone does not prevent preterm birth, nor does it improve perinatal outcomes in unselected twin gestations, but it appears to reduce the risk of preterm birth occurring at early gestational ages and of neonatal morbidity and mortality in twin gestations with a sonographic short cervix. However, more evidence is needed before recommending this intervention to this subset of patients.

Fetal-Maternal Hemorrhage in First-Trimester Intrauterine Hematoma

OBJECTIVE

The objective of this study was to compare the frequency and percentage of fetal hemoglobin (HbF%) by flow cytometry of (1) first-trimester asymptomatic patients with intrauterine hematoma (IUH), (2) first-trimester pregnant patients with vaginal bleeding (VB), and (3) first-trimester asymptomatic pregnant women without hematoma.

METHODS

Prospective study involving pregnant women in the first trimester of pregnancy. Patients with ultrasound findings of asymptomatic hematoma and with VB were paired with asymptomatic pregnant women of same gestational age without hematoma (control group [CG]). Maternal blood HbF% was evaluated by flow cytometry. The groups were compared in terms of circulating fetal hemoglobin and HbF%.

RESULTS

Sixty-six patients were selected, 22 with hematoma, 17 with bleeding, and 27 in the CG. Fetal hemoglobin was detected in 15 patients with hematoma (68.2%) and 13 with bleeding (76.5%) and in 20 of the control (74.1%) (p = 0.830). The mean HbF% of each group was 0.054, 0.012, and 0.042 for hematoma, bleeding, and control, respectively, and differences were not significant (p = 0.141). There was a moderate negative correlation between the volume of hematoma and HbF% (rSpearman = -0.527; p = 0.012).

CONCLUSIONS

The fetal-maternal hemorrhage expressed by Hbf% in first-trimester pregnancies did not seem to differ between patients with and without ultrasound findings of IUH.

Risk factors for gastroschisis: A case-control study in a Brazilian population

OBJECTIVE

To evaluate risk factors associated with fetal gastroschisis.

METHODS

As a secondary aim of a larger case-control study, pregnant women attending the Fetal Medicine Unit at the Department of Obstetrics and Gynecology at Hospital das Clinicas, Sao Paulo University Medical School between July 1, 2013, and July 31, 2015, were allocated into either the gastroschisis group, where the woman was carrying a fetus with gastroschisis, or the control group, where the fetus was normal. Patients in the control group were matched at study entry for maternal age, preconception body mass index and weeks of gestation. In-person interviews were conducted during pregnancy to obtain data on demographic, medical, and social characteristics; exposure to substances; pregnancy history; the presence of chronic disease, urinary tract infections (UTIs), influenza, and fever; and the occurrence of stress events between the month before the last menstrual period and the first trimester of pregnancy.

RESULTS

Of 171 women included in the study, 57 were allocated to the gastroschisis group and 114 to the control group. There were significant associations between gastroschisis and maternal UTI (P=0.011), tobacco use (P=0.001), alcohol consumption (P≤0.001), and illicit drug use (P=0.012). After analysis by standard logistic regression, the remaining significant factors were UTI, tobacco use, and alcohol consumption.

CONCLUSION

UTI and exposure to tobacco or alcohol just before conception and during early pregnancy were associated with an increase in the likelihood of fetal gastroschisis.

Fetal intra-abdominal bowel dilation in prediction of complex gastroschisis

OBJECTIVE

To investigate intra-abdominal bowel dilation (IABD) in the prediction of complex gastroschisis.

METHODS

This was a retrospective study of 174 singleton pregnancies with isolated fetal gastroschisis, resulting in live birth and with available ultrasound images from visits at both 20-22 and 30-32 weeks' gestation. IABD was measured as the greatest transverse diameter of the most dilated intra-abdominal bowel segment, by an operator blinded to postnatal outcome. The distribution of IABD measurements in those with complex and those with simple gastroschisis was determined and the best cut-off value to predict complex gastroschisis was selected using receiver-operating characteristics (ROC) curves. The area under the ROC curve (AUC), detection rate (DR), false-positive rate (FPR), positive predictive value (PPV) and negative predictive value (NPV) were determined.

RESULTS

The study population included 39 (22.4%) cases of complex and 135 (77.6%) cases of simple gastroschisis. In the prediction of complex gastroschisis, the AUC at 20-22 weeks' gestation was 0.742 (95% CI, 0.628-0.856) and the respective value for 30-32 weeks was 0.820 (95% CI, 0.729-0.910). At the IABD cut-off of 7 mm at 20-22 weeks, DR, FPR, PPV and NPV for complex gastroschisis were 61.5%, 6.7%, 72.7% and 89.4%, respectively, and at IABD cut-off of 14 mm at 30-32 weeks, the respective values were 64.9%, 5.9%, 75.0% and 90.7%.

CONCLUSION

Measurement of IABD at 20-22 or at 30-32 weeks' gestation is useful in the prediction of complex gastroschisis. Copyright © 2019 ISUOG. Published by John Wiley & Sons Ltd.

Maternal nutrient intake and fetal gastroschisis: A case-control study

Fetal gastroschisis is a paraumbilical abdominal wall defect with herniation of the abdominal organs. This multifactorial malformation occurs in young pregnant women, and the underlying cause of the disease remains unknown; however, nutritional factors may play a role in its development. This case-control study explored the association of maternal nutrient intake with the occurrence of gastroschisis. The gastroschisis group (GG) comprised 57 pregnant women with fetuses with gastroschisis, and the control group (CG) comprised 114 pregnant women with normal fetuses matched for maternal age, gestational age, and preconception body mass index classification. Nutritional assessments related to the preconception period were obtained using the food consumption frequency questionnaire, and nutrient intakes were calculated using nutrition programs. The median daily calorie intake was higher (2,382.43 vs. 2,198.81; p = .041) in the GG than in the CG. The median intake of methionine (763.89 vs. 906.34; p = .036) and threonine (1,248.34 vs. 1,437.01; p = .018) was lower in the GG than in the CG. Pregnant women with fetuses with gastroschisis have a diet characterized by higher calorie intake and lower levels of essential amino acids (methionine and threonine) during the preconception period than pregnant women with normal fetuses.

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.

The effect of prenatal vaginal progesterone on cervical length in nonselected twin pregnancies

PURPOSE

The aim of this study was to investigate the influence of vaginal progesterone on cervical length (CL) in asymptomatic nonselected twin gestations.

METHODS

This was a secondary analysis of a randomized, double-blind, placebo-controlled trial of twin pregnancies exposed to vaginal progesterone or placebo. The CL was examined at six different time periods: 18-21⁺⁶ weeks (T1), 21-23⁺⁶ weeks (T2), 24-26⁺⁶ weeks (T3), 27-29⁺⁶ weeks (T4), 30-32⁺⁶ weeks (T5) and 33-34⁺⁶ weeks (T6). The rate of cervical shortening per week and the percent cervical shortening were compared between the groups, with analyses of the entire cohort and of those who delivered spontaneously according to gestational age at birth.

RESULTS

The final analysis included 184 women in the progesterone group and 188 women in the placebo group. The baseline characteristics were similar in both groups. No differences in cervical shortening in terms of absolute value or percent shortening were observed between the groups at each time period or throughout gestation. Furthermore, no difference was found in cervical shortening for those who delivered spontaneously.

CONCLUSION

Cervical shortening in asymptomatic nonselected twin pregnancies occurred at a similar rate, regardless of vaginal progesterone treatment.

Outcome of isolated gastroschisis; an international study, systematic review and meta-analysis

OBJECTIVE

To determine outcome of children born with isolated gastroschisis (no extra-gastrointestinal congenital abnormalities).

STUDY DESIGN

International cohort study and meta-analysis.

PRIMARY OUTCOME

time to full enteral feeding (TFEF); secondary outcomes: Duration of mechanical ventilation, length of stay (LOS), mortality and differences in outcome between simple and complex gastroschisis (complex; born with bowel atresia, volvulus, perforation or necrosis). To compare the cohort study results with literature three databases were searched. Studies were eligible for inclusion if cases were born in developed countries with isolated gastroschisis after 1990, number of cases >20 and TFEF was reported.

RESULTS

The cohort study included 204 liveborn cases of isolated gastroschisis. The TFEF, median duration of ventilation and LOS was, 26days (range 6-515), 2days (range 0-90) and 33days (range 11-515), respectively. Overall mortality was 10.8%. TFEF and LOS were significantly longer (P<0.0001) and mortality was fourfold higher in the complex group. Seventeen studies, amongst the current study, were included for further meta-analysis comprising a total of 1652 patients. Mean TFEF was 35.3±4.4days, length of ventilation was 5.5±2.0days, LOS was 46.4±5.2days and mortality risk was 0.06 [0.04-0.07 95%CI]. Outcome of simple and complex gastroschisis was described in five studies. TFEF, ventilation time, LOS were significant longer and mortality rate was 3.64 [1.95-6.83 95%CI] times higher in complex cases.

CONCLUSIONS

These results give a good indication of the expected TFEF, ventilation time and LOS and mortality risk in children born with isolated gastroschisis, although ranges remain wide. This study shows the importance of dividing gastroschisis into simple and complex for the prediction of outcome.

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.

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.

Placental transfer of IgG antibodies specific to Klebsiella and Pseudomonas LPS and to group B Streptococcus in twin pregnancies

Group B Streptococcus (GBS), Klebsiella spp. and Pseudomonas spp. are important aetiological agents of neonatal infections in Brazil. There is a lack of data in the literature regarding the specific transport of immunoglobulin G (IgG) against these pathogens in multiple pregnancies. Maternal (n = 55) and umbilical cord (n = 110) blood samples were prospectively collected at birth from 55 twin pregnancies. The factors associated with cord levels and transfer ratios of IgG against GBS, Klebsiella and Pseudomonas were examined. The IgG umbilical cord serum levels specific to GBS, Klebsiella LPS and Pseudomonas LPS were significantly associated with maternal-specific IgG concentrations and the presence of diabetes. The anti-Klebsiella IgG cord serum concentrations were also related to birthweight and the presence of hypertension. The transfer ratios against GBS and Pseudomonas LPS were associated with maternal-specific IgG concentrations. The transfer ratios for GBS and Pseudomonas LPS were associated with gestational age at delivery and the presence of diabetes, respectively. None of the examined parameters were related to Klebsiella LPS transfer ratios. We conclude that in twin pregnancies, specific maternal IgG serum concentrations and diabetes were the parameters associated with umbilical cord serum IgG concentrations reactive with the three pathogens investigated. All the other parameters investigated showed different associations with neonatal-specific IgG levels according to the antigen studied. There was no uniformity of the investigated parameters regarding association with placental IgG transfer ratios against the GBS, Pseudomonas LPS and Klebsiella LPS.

Longitudinal reference range for umbilical cord cross-sectional area in twin pregnancies at 18-32 weeks of gestation

OBJECTIVES

The objectives of this study were to establish gestational age-specific reference ranges for cross-sectional area of the umbilical cord, and its components, in twin pregnancies and to compare them with previously reported singleton reference ranges.

METHODS

This was a prospective longitudinal study involving uncomplicated dichorionic twin pregnancies. Sonographic measurements of the cross-sectional area of the umbilical cord, umbilical vein and arteries and Wharton's jelly were obtained in a plane adjacent to the fetal abdomen, every 3 weeks, between 18 and 32 weeks of gestations. Multilevel regression analysis was used to determine gestational age-specific reference ranges for each parameter, and these were plotted against singleton pregnancy references.

RESULTS

Three hundred and thirty four ultrasound scans were performed in 44 twin pregnancies, between 18 and 32.9 weeks (mean: 3.8 ± 0.7 scans/pregnancy and mean interval between scans: 3.3 ± 0.9 weeks). All umbilical cord cross-sectional areas (total, vein, artery and Wharton's jelly) showed a significant increase with gestational age. Compared with singleton pregnancy ranges, mean values were considerably lower in twin pregnancies and resemble the lower limits observed in singletons.

CONCLUSION

In twin pregnancies, cross-sectional area of the umbilical cord, and its components, increases between 18 and 32 weeks, and mean values are substantially lower compared with singleton pregnancies.

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.

Conjoined twins pregnancies: experience with 36 cases from a single center

OBJECTIVE

To review a single center's experience in the management of twin pregnancies with conjoined fetuses.

METHODS

Retrospective study describing prenatal findings, delivery details, surgical treatment and perinatal outcome.

RESULTS

The study included 36 twin pregnancies with conjoined twins seen over a period of 12 years in a single tertiary hospital: 69.4% were thoracopagus, 13.9% parapagus, 8.3% omphaloischiopagus 5.6% omphalopagus and 2.8% cephalopagus. Cardiac defects were present in 91.6% of twin pairs and associated malformations were present in 61.8% of the cases: limb abnormalities in 36.1%, abdominal wall defects in 25.0%, cleft lip and/or palate in 13.9% and congenital diaphragmatic hernia in 5.5%. Surgical separation was considered not feasible and prognosis lethal in 30 (83.3%) cases. Termination of pregnancy was performed in 12 pregnancies of poor prognosis. Cesarean section was performed in all remaining cases. Five sets of twins underwent surgical separation and six children survived. Overall survival in our series was 8.3% and, among the livebirths, 13.6%.

CONCLUSION

Conjoined twin pregnancies should be referred to tertiary centers for detailed fetal anomaly and echocardiographic assessment to evaluate prognosis and determine the possibility of postnatal surgical separation.

Prenatal sonographic prediction of twin growth discordance

Our aim was to evaluate the ability of prenatal ultrasound scans to predict fetal growth discordance, and to examine the correlation between fetal weight estimated by ultrasound with actual birthweight in twin pregnancies. The study consisted of 221 twin pregnancies with ultrasound fetal weight estimates based on Hadlock's 4 parameter formula. Prediction of intertwin birthweight discordance was examined at 4 different intervals between ultrasound examination and delivery (0–7 days, n = 96; 8–14 days, n = 66; 15–21 days, n = 58; 22–28 days, n = 59 pregnancies), with a total of 279 ultrasound examinations. Birthweight discordance was considered as a difference of 20% or greater. The correlation between fetal weight estimated between 0 and 7 days and actual birthweight was calculated by intraclass correlation coefficient. The predictive values for intertwin discordance of 20% or more in the 0 to 7 days group were: sensitivity = 93.6%, specificity = 79.4%, positive predictive value = 89.2%, negative predictive value = 87.1% and accuracy = 88.6%. In the groups with scans carried out between 8 and 14 days, 15 and 21 days, and 22 and 28 days, the sensitivity and accuracy values were 95.8% and 84.9%, 95.6% and 84.5%, 90.9% and 84.8%, respectively. Fetal growth discordance in twins can be accurately predicted by ultrasound examination performed up to 28 days before birth. There is a good correlation between fetal weight estimated between 0 and 7 days and actual birthweight.

Placental lakes on sonographic examination: correlation with obstetric outcome and pathologic findings

PURPOSE

The aim of this study was to compare pregnancy outcome and pathologic findings in cases of placental lake visualized on sonography in pregnancies without concurrent fetal or maternal disease.

METHODS

Placental aspect was evaluated sonographically in 4,106 singleton pregnancies without maternal or fetal disease at between 15 and 34 weeks3 gestation. Fifty-nine cases presenting with placental lakes were followed through the end of pregnancy. Obstetric outcome was compared with that of cases with sonographically normal placental aspects (n=37). Macroscopic and microscopic examinations for pathology were also performed in a few cases in both groups.

RESULTS

Placental lakes were present in 2.2% (92/4,106) of the cases. No statistically significant difference was observed in birth weight, gestational age at delivery, adverse obstetric outcome, and macroscopic or microscopic results between the control and study groups.

CONCLUSION

Our findings do not seem to indicate an increase in the risk for an adverse pregnancy outcome in cases presenting with placental lakes.

Sonographic markers of exencephaly below 10 weeks' gestation

We report two cases of exencephaly diagnosed by transvaginal ultrasonography at 8 weeks 4 days and at 9 weeks 3 days of gestation. Both cases presented an irregular cephalic pole, and, in the case seen at 8 weeks 4 days, brain vesicles were also absent, whereas in the case seen at 9 weeks 3 days, the midline echo was indistinguishable with disorganized choroid plexuses. In both cases, anencephaly was evident at 11 and 12 weeks' gestation and the postmortem confirmed the diagnosis.

Ductus venosus blood flow assessment at 11 to 14 weeks of gestation and fetal outcome

OBJECTIVE

To evaluate the association between abnormal ductus venosus (DV) at 11-14 weeks' gestation and chromosomal abnormalities, structural defects and fetal outcome.

METHODS

DV flow-velocity waveform (DV-FVW) and nuchal translucency thickness (NT) were prospectively evaluated in 1217 singleton pregnancies.

RESULTS

The DV-FVW was abnormal in 84 fetuses, NT was above the 95th centile in 160 fetuses and both markers were observed in 41 fetuses. Chromosomal defects were diagnosed in 22 fetuses. The sensitivity, specificity and positive and negative predictive values for an abnormal karyotype were 86.4%, 86.9%, 11.9% and 99.7%, respectively, for an increased NT. These values were 68.2%, 96.9%, 31.3% and 99.3%, respectively, for DV-FVW abnormalities and 68.2%, 97.6%, 36.6% and 99.3%, respectively, when both markers were found simultaneously. Regarding structural defects, these values were 43.8%, 92.9%, 8.3% and 99.1% for an abnormal NT, 25.0%, 92.6%, 4.8% and 98.8% for DV-FVW abnormalities and 25.0%, 97.9%, 15.4% and 98.9% for both together. Considering those cases of unexplained fetal demise, the values were 44.4%, 85.9%, 5.0% and 98.9% for NT abnormalities, 22.2%, 92.6%, 4.8% and 98.6% for an abnormal DV-FVW and 22.2%, 98%, 15.4% and 98.7% for both. In cases with increased NT, the percentage of live births with normal karyotype and no major fetal structural defects decreased from 93.8% in normal DV-FVW fetuses to 77.3% in abnormal ones.

CONCLUSION

DV assessment at 11-14 weeks' gestation is useful in screening for fetal chromosomal abnormalities and may help to reduce the false-positive rate when combined with NT measurement. Abnormal DV-FVW is also associated with an increase in adverse perinatal outcome in fetuses with enlarged NT. However, the value of DV-FVW assessment in cases with normal NT is unclear.

Structural and functional cardiac abnormalities identified prior to 16 weeks' gestation in fetuses with increased nuchal translucency

OBJECTIVE

To determine the accuracy and practicality of fetal echocardiography in the identification of structural and functional cardiac abnormalities prior to 16 weeks' gestation in fetuses with increased nuchal translucency thickness (NT).

METHODS

Between January 1996 and June 2002 early fetal echocardiography using the transvaginal route was performed at 12-16 weeks' gestation on 275 fetuses with increased NT. The abnormal cardiac findings were classified as either structural (congenital heart defects) or functional, defined as transient phenomena which might later disappear, such as isolated tricuspid regurgitation and an enlarged ascending aorta. The abnormal findings were related to pregnancy outcome, including autopsy results, karyotyping results, and late fetal and neonatal echocardiography.

RESULTS

Cardiac abnormalities were present in 61 fetuses overall (22.2%); including structural cardiac defects in 37 fetuses (13.5%) and functional abnormalities in 24 fetuses (8.7%). Structural cardiac abnormalities were associated with abnormal karyotype in 24 fetuses and normal karyotype in 13 fetuses. Of the 24 fetuses with functional cardiac abnormalities, 2 (8.3%) had isolated tricuspid regurgitation and 22 (91.7%) had enlarged ascending aorta. Abnormal karyotype was present in this group in 4 cases (16.7%).

CONCLUSION

Increased NT can be used to define a high-risk group that should receive specialized early fetal echocardiography. This is a reliable technique with great potential for the diagnosis of both structural and functional cardiac abnormalities.

Cervical length at 11-14 weeks' and 22-24 weeks' gestation evaluated by transvaginal sonography, and gestational age at delivery

OBJECTIVE

To compare cervical length measurements obtained at 11 to 14 weeks and 22 to 24 weeks of gestation in an unselected group of pregnant women and to correlate the measurements with time of delivery.

METHODS

This was a prospective study involving 529 pregnant women attending for routine antenatal care who underwent transvaginal scans at 11-14 weeks and 22-24 weeks for evaluation of cervical length. The mean cervical length was calculated at both stages of gestation and lengths were compared between groups which delivered at term or prematurely, this being defined as delivery before 37 completed weeks of gestation.

RESULTS

The mean cervical lengths at 11-14 and 22-24 weeks were, respectively, 42.4 mm and 38.6 mm. Cervical length at 11-14 weeks was not significantly different between the groups which delivered at term (42.7 mm) and preterm (40.6 mm). However, at the 22-24-week evaluation, cervical length was significantly shorter in the group which had a preterm delivery than in that which had a term delivery (26.7 mm and 39.3 mm, respectively; P = 0.0001). In the group of women with a previous history of one or more preterm deliveries, there was a greater shortening in cervical length from the first to the second evaluation than there was in the group of women with no previous history of preterm delivery. This shortening was also more pronounced in the group which delivered prematurely (from 40.6 mm to 26.7 mm) than in that which delivered at term (from 42.7 mm to 39.3 mm).

CONCLUSION

There is a spontaneous shortening in the pregnant cervix from the first to the second trimester of pregnancy. The shortening is more rapid in pregnant women who deliver prematurely and who have a history of previous preterm delivery.

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.

Transvaginal ultrasonography in predicting placenta previa at delivery: a longitudinal study

OBJECTIVES

To determine the extent of overlapping of the internal cervical os by the lower placental edge at 11-14 weeks' gestation which best predicts placenta previa at term.

PATIENTS AND METHODS

This was a prospective study initially involving 381 singleton pregnancies with a live fetus at 11-14 weeks attending for routine antenatal care. The distance between the lower placental edge and the internal cervical os was longitudinally evaluated by transvaginal ultrasound examination at 11-14 weeks', 20-24 weeks', and 30-34 weeks' gestation. The first 203 cases were selected at random (first phase) and after this period only cases with the lower placental edge reaching and/or overlapping the internal cervical os were followed up (n = 170, second phase). Thus a total of 373 cases were analyzed, 351 of whom were examined in all three trimesters. Multiple regression analysis was used to estimate the probability of predicting placenta previa at term using the overlap of the lower placental edge over the internal cervical os in the first trimester of pregnancy.

RESULTS

A change in the relative position of the placenta (placental migration) was observed in all 351 cases examined in the three trimesters of pregnancy. In the general population, represented by the 203 cases (first phase), the incidence of placenta previa at 11-14 weeks' gestation was 42.3% (86/203), at 20-24 weeks' 3.9% (8/203) and at term 1.9% (4/203). A total of 18 cases of placenta previa and 17 cases of marginal placenta were observed at term. It was estimated that when the lower placental edge overlaps the internal cervical os by 23 mm at 11-14 weeks the probability of placenta previa at term is 8% with a sensitivity of 83.3% and specificity of 86.1%.

CONCLUSION

The present study establishes the probability of placenta previa at term depending on the relationship of the lower placental edge to the internal cervical os at 11-14 weeks.

Effect of maternal position on cervical length measurement in twin pregnancies

OBJECTIVE

To compare cervical length measurements in twin pregnancies obtained from patients in the recumbent and standing positions.

METHODS

Fifty women with uncomplicated twin pregnancies underwent monthly transvaginal ultrasound examinations for cervical length measurement in the recumbent and standing positions. The correlation between cervical length measurements obtained in the recumbent and standing positions, and between these measurements and gestational age, were examined. The significance of the differences between measurements obtained in the recumbent and standing positions was also analyzed.

RESULTS

Based on data obtained at the first ultrasound examination, there was a significant correlation between cervical length measurements in the recumbent and standing positions (r = 0.77; t = 8.25; P < 0.0001) and both measurements showed a significant inverse correlation with gestational age (recumbent position: r = -0.60, P < 0.0001; standing position: r = -0.46; P = 0.0008). The mean of the differences (standing - recumbent) was -1.8 mm (95% confidence interval = -3.7-0.04; t = -1.96; P = 0.06) and the mean of percentage differences ((standing - recumbent)/recumbent x 100) was -2.9% (95% confidence interval = -8.6-2.7; t = -1.04; P = 0.3). When the data obtained at all examinations were examined by multiple regression analysis, cervical length measurement in the recumbent position was the only parameter that correlated significantly with the percentage difference between cervical length measurements (P < 0.0001).

CONCLUSIONS

Cervical length in twin pregnancies decreases with gestation and there is a good correlation between measurements obtained from women in the recumbent and standing positions. No significant changes in cervical length were observed comparing measurements obtained in the two maternal positions.

Detection of fetal structural abnormalities at the 11-14 week ultrasound scan

The aim of this study was to evaluate the detection of fetal structural abnormalities by the 11-14 week scan. 2853 pregnant women were submitted to a routine ultrasound scan between the 11th and 14th week and the fetal skull, brain, spine, abdominal wall, limbs, stomach and bladder were examined. Following the scans the patients were examined in the second or third trimester of pregnancy. An isolated increased nuchal translucency was not considered an abnormality. However, these patients had an early echocardiography assessment. Fetal structural abnormalities were classified as major or minor and of early or late onset. A total of 130 (4.6%) defects were identified and 29 (22.3%) of these were diagnosed at the 11-14 week scan, including nine cardiac defects associated with increased nuchal translucency. The antenatal ultrasound detection rate was 71.5%, and 31.2% were detected in the first-trimester assessment. 78.8% of the major defects were diagnosed by the prenatal scan and 37.8% by the 11-14 week scan. Fetal structural abnormalities at the 11-14 week scan were detected in approximately 22.3% of the cases, therefore, a second-trimester anomaly scan is important in routine antenatal care to increase the prenatal detection of fetal defects.

First-trimester screening for chromosomal abnormalities by fetal nuchal translucency in a Brazilian population

OBJECTIVES

To examine the detection rate of chromosomal abnormalities using nuchal translucency (NT) thickness in a Brazilian population.

METHODS

This was a prospective study of 2996 singleton pregnancies with a live fetus at 10-14 weeks of gestation attending for routine antenatal care in a teaching hospital in Brazil. Fetal crown-rump length (CRL) and NT thickness were measured and the risks for trisomy 21 were calculated by a combination of maternal age and fetal NT with the use of software provided by The Fetal Medicine Foundation. Sensitivity and positive predictive values for different risk cut-offs were calculated.

RESULTS

Chromosomal defects were diagnosed in 22 cases, including 10 cases of trisomy 21. The estimated risk based on maternal age and fetal NT was 1 in 300 or greater in 222 (7.4%) cases and these included nine of 10 (90.0%) pregnancies with trisomy 21 and nine of 12 (75.0%) pregnancies with other chromosomal defects. The NT was above the 95th centile in 5.8% of cases and this group included 70% of the trisomy 21 cases.

CONCLUSION

A combination of maternal age and fetal NT provides an effective method of screening for chromosomal defects. The performance of the test in a Brazilian population is similar to that in Britain.

Trisomy 10: ultrasound features and natural history after first trimester diagnosis

We report on the ultrasound features and natural history of trisomy 10. At 12 weeks' gestation in a routine scan examination, the fetus presented with increased nuchal translucency thickness, mild skin oedema, bilateral pleural effusion, marked micrognathia, cardiomegaly, unilateral talipes and reversed A-wave in the ductus venosus blood flow. Karyotyping on chorionic villus sampling (CVS) led to the diagnosis of trisomy 10, which was confirmed by fetal blood sampling at 22 weeks' gestation. As the parents opted to continue with the pregnancy, the natural history and following ultrasound features are described. This is the third case of trisomy 10 in the literature reporting on the physical features. The most frequent ultrasound findings presented in trisomy 10 are increased nuchal translucency, micrognathia, renal agenesis, facial cleft, limbabnormalities, cardiac defects and early severe growth retardation.

Placental mRNA expression of alpha and beta human chorionic gonadotrophin in early trisomy 18 pregnancies

The placental expression of human chorionic gonadotrophin (HCG) I- and beta-subunits was investigated in eight pregnancies presenting with trisomy 18 and in 30 normal pregnancies at 11-15 weeks gestation. In the control group, the median densitometric scores of placental beta-HCG and I-HCG mRNA were 1.23 and 1.74 respectively. In the trisomy 18 group the median beta-HCG mRNA was significantly lower (0.16, Z = 2.29, P < 0.05) but alpha-HCG [0.60, Z = 1.75, P = 0.08) was not significantly different from normal. These findings suggest that in trisomy 18 the decrease in maternal serum concentration of HCG subunits results from an impairment in the transcription of the corresponding gene which affects the beta subunit to a greater extent than the I subunit.

Cardiac gene expression of atrial natriuretic peptide and brain natriuretic peptide in trisomic fetuses

OBJECTIVE

To investigate whether the increased nuchal translucency of trisomic fetuses is the consequence of heart failure by examining cardiac expression of atrial natriuretic peptide and brain natriuretic peptide genes.

METHODS

Cardiac atrial natriuretic peptide and brain natriuretic peptide messenger RNA (mRNA) levels were measured in fetal hearts from 15 pregnancies affected by trisomy 21 or 18 at 12-16 weeks' gestation and from 30 normal controls at 10-20 weeks.

RESULTS

In normal fetuses, mRNA levels of atrial natriuretic peptide decreased, but levels of brain natriuretic peptide did not change significantly with gestation. In trisomic fetuses, mRNA levels of both atrial natriuretic peptide and brain natriuretic peptide were significantly higher than in gestational age-matched normal controls.

CONCLUSION

These data demonstrate that atrial natriuretic peptide and brain natriuretic peptide genes are transcribed prenatally, and the findings in trisomic fetuses suggest that the increased translucency of trisomic fetuses may be the consequence of heart failure.

Fetal hepatic alpha-fetoprotein mRNA expression in fetuses with trisomy 21 and 18 at 12-15 weeks gestation

In this study we examined alpha-fetoprotein (AFP) mRNA expression in fetal liver at 12-15 weeks of gestation in trisomy 21 (n = 13), trisomy 18 (n = 5) and control fetuses (n = 24). No significant difference was found in the steady-state level of fetal liver AFP mRNA levels in either of the two trisomy groups studied. These findings suggest that the decrease in maternal serum AFP concentration found in trisomic pregnancies is unlikely to be the consequence of impaired transcription of the AFP gene by the fetal liver.

Gene expression of human pregnancy-associated plasma protein-A in placenta from trisomic pregnancies

Placental pregnancy-associated plasma protein-A (PAPP-A) mRNA expression, placental PAPP-A protein concentration and maternal serum levels of PAPP-A were examined in pregnancies affected by trisomy 21 (n=8), trisomy 18 (n=7) and 15 normal controls at 12-15 weeks of gestation. The maternal serum concentration of PAPP-A in the trisomic group of pregnancies was significantly lower than in the normal controls. However there were no significant differences between the three groups in PAPP-A mRNA expression or PAPP-A protein concentration in the placental tissues. There was no significant association between the level of placental mRNA and either placental protein or maternal serum PAPP-A concentrations in the normal or trisomic pregnancies. There was however a significant association between placental protein and maternal serum PAPP-A concentrations in the normal and trisomy 21 pregnancies but not in those affected by trisomy 18. These findings suggest that the decrease in maternal serum PAPP-A in trisomic pregnancies is due to alternations in post-translational events such as protein stability, alterations in the release mechanism of the protein, impaired protein transport across the placenta or modified serum stability of PAPP-A.

Comparison of chorion villus sampling and early amniocentesis for karyotyping in 1,492 singleton pregnancies

This was a prospective study in 1,492 women with singleton viable pregnancies undergoing chorion villus sampling (CVS) or early amniocentesis (EA) at 10-13 weeks of gestation because of advanced maternal age, parental anxiety or family history of chromosomal abnormality in the absence of parental chromosomal rearrangement. They were offered the option of having CVS or EA, or to be randomised into one of the two tests. CVS was performed in 652 cases (375 by choice and 277 by randomisation) and EA was performed in 840 cases (562 by choice and 278 by randomisation). Both procedures were carried out by transabdominal ultrasound-guided insertion of a needle (20 gauge) using a free-hand technique. The two techniques were similar in providing a sample (CVS 99.3%, EA 100%) and in giving a non-mosaic cytogenetic result (CVS 97.5%, EA 97.9%). Spontaneous loss (intrauterine or neonatal death) after EA (total group 4.9%, randomised subgroup 5.8%) was significantly higher than after CVS (total group 2.1%, randomised subgroup 1.8%; difference 2.8%, 95% CI 1.3-4.3%, and difference 4%, 95% CI 1.3-6.7%). The gestation at delivery and birth weight of the infants after EA and CVS were similar. In the EA group the incidence of talipes equinovarus (1.66%) was higher than in the CVS group (0.48%), but this difference was not significant.

Placental expression of alpha and beta subunits of human chorionic gonadotrophin in early pregnancies with Down's syndrome

This study examines the expression of alpha and beta subunits of human chorionic gonadotrophin (HCG) in samples of placental and decidual tissue obtained at 11-15 weeks of gestation from 30 control pregnancies and 11 pregnancies with trisomy 21. In the placental tissue, the concentrations of beta-HCG mRNA and alpha-HCG mRNA were augmented in six and seven of the trisomy 21 cases respectively and in 16 and 14 of the control pregnancies. The median values of beta-HCG mRNA and alpha-HCG mRNA in the two groups were not significantly different. Although the median serum free beta-HCG concentration was significantly (P = 0.03) higher in trisomy 21 pregnancies than the controls, there was no relationship between serum free beta-HCG and relative abundance of beta-HCG mRNA in either the trisomy 21 pregnancies or the controls. Decidual expression of beta-HCG and alpha-HCG mRNA were below detection level in the Northern blot analysis in both the trisomy 21 pregnancies and the controls. These findings suggest that the increase in maternal serum free beta-HCG concentration in trisomy 21 pregnancies occurs during the post-transcriptional phase of HCG protein biosynthesis.

Maternal serum Schwangerschafts protein-1 (SP1) and fetal chromosomal abnormalities at 10-13 weeks' gestation

Maternal serum SP1 concentration was measured at 10-13 weeks' gestation in samples from 87 pregnancies with fetal chromosomal abnormalities (trisomy 21 n = 45; trisomy 18 n = 19; trisomy 13 n = 8; Turner syndrome n = 7; 47,XXX or 47,XXY n = 4; triploidy n = 4), and in samples from 348 matched controls. In the control group, SP1 increased significantly with fetal crown-rump length (r = 0.20, P < 0.0001) and there was no significant association with fetal nuchal translucency thickness (r = 0.03). Similarly, in the group with fetal chromosomal abnormalities, SP1 increased significantly with crown-rump length (r = 0.31, P < 0.01) and there was no significant association with nuchal translucency thickness (r = -0.08). In the groups with fetal trisomy 18 and trisomy 13, the median SP1 (0.76 MoM and 0.57 MoM, respectively) was significantly lower than in the controls (z = 2.64 and z = 3.27, respectively); in 21% and 25% of the cases, values were below the 5th centile. In the group with trisomy 21 and other chromosomal abnormalities the median SP1 (0.96 MoM and 0.93 MoM, respectively) was not significantly different from controls (z = 1.17 and z = 0.67, respectively). Measurement of SP1 concentration at 10-13 weeks' gestation is not likely to be useful in the prediction of fetal chromosomal abnormalities.

Fetal exomphalos at 11 to 14 weeks of gestation

In an ultrasonographic screening study at 11 to 14 weeks' gestation involving 9885 singleton pregnancies, the prevalence of exomphalos was 0.11% (11 cases) and the prevalence of trisomy 18 or 13 was 0.35% (35 cases). The mean maternal age of the screened population was 35 years (range, 15 to 47 years) and a significant association was found between maternal age and both the prevalence of trisomies and the prevalence of exomphalos. Because the frequency of exomphalos in fetuses with trisomy 18 or 13 was 17% and in those with no evidence of these trisomies it was 0.05%, the risk for trisomies in fetuses with exomphalos is 340 times higher than in those without exomphalos.

Repeatability of measurement of fetal nuchal translucency thickness

The aim of this prospective study was to assess the repeatability of measurement of fetal nuchal translucency thickness at 10-14 weeks' gestation. The nuchal translucency was measured by two of four operators in 200 pregnant women attending the Harris Birthright Research Centre for Fetal Medicine at 10-14 weeks' gestation. To assess repeatability of different components of variability, six measurements of nuchal translucency were made on each fetus, with a total of 1200 measurements. The data of this study demonstrate that 95% of the time the intraobserver, interobserver and caliper placement repeatability of measuring fetal nuchal translucency were less than 0.54 mm, 0.62 mm and 0.58 mm, respectively. In addition, the repeatability was unrelated to the size of the nuchal translucency. The findings of this study demonstrate that, when the nuchal translucency thickness is measured by well-trained operators, the measurement is highly reproducible.

Maternal serum hCG and fetal nuchal translucency thickness for the prediction of fetal trisomies in the first trimester of pregnancy

OBJECTIVE

To compare the potential value of maternal serum total hCG and free beta-hCG in predicting the risk for fetal trisomies during the first trimester of pregnancy and to examine whether data on maternal hCG and fetal nuchal translucency thickness can be combined to derive risks.

METHODS

Maternal serum total hCG and free beta-hCG were measured in samples from 83 singleton pregnancies with fetal chromosomal abnormalities (trisomy 21 (n = 41), trisomy 18 (n = 19), trisomy 13 (n = 8) sex chromosome aneuploidies (n = 11), triploidy (n = 4) and 394 chromosomally normal controls at 10 to 13 weeks gestation. In all cases, the fetal nuchal translucency thickness was measured at the time of fetal karyotyping.

RESULTS

In the 249 chromosomally normal controls with fetal nuchal translucency less than 3 mm, total hCG and free beta-hCG decreased significantly with increased fetal crown-rump length. In 145 chromosomally normal fetuses with nuchal translucency 3 to 9 mm total hCG and free beta-hCG were not significantly different from the 249 with nuchal translucency less than 3 mm. In fetuses with trisomy 21, total hCG and free beta-hCG were significantly higher, whereas in trisomies 18 and 13 levels were lower than in chromosomally normal controls. When the cutoff levels for total hCG and free beta-hCG were selected to include 4% of chromosomally normal fetuses, the detection rates for trisomy 21 were 24% and 32%, respectively. There was no significant association between hCG and nuchal translucency thickness in either the chromosomally normal (r = -0.01) or abnormal group (r = -0.15).

CONCLUSION

An improved estimate of risk for fetal trisomies at 10 to 13 weeks gestation can be derived by combining data on maternal age, maternal serum total or free beta-hCG and fetal nuchal translucency thickness.

First trimester maternal serum alpha-fetoprotein in fetal trisomies

OBJECTIVE

To evaluate the potential value of maternal serum alpha-fetoprotein concentration in the detection of fetal trisomy at 10 to 13 weeks gestation and to examine the possible association between maternal serum alpha-fetoprotein and fetal nuchal translucency thickness.

DESIGN

Cross-sectional study.

SETTING

Harris Birthright Research Centre for Fetal Medicine, King's College Hospital Medical School, London.

SUBJECTS AND METHODS

Maternal serum alpha-fetoprotein concentration was measured at 10 to 13 weeks gestation in samples from 57 pregnancies with fetal trisomies (trisomy 21 (n = 35), trisomy 18 (n = 16), and trisomy 13 (n = 6)) in 228 matched controls in whom the fetal nuchal translucency was < 3 mm and in 114 chromosomally normal fetuses with translucency > or = 3 mm.

RESULTS

In the control group maternal serum alpha-fetoprotein increased significantly with fetal crown-rump length (r = 0.451). In this group, the median maternal serum alpha-fetoprotein was not significantly different from that in the groups with trisomy 21 (median = 0.84 MoM), trisomy 18 (median = 0.86 MoM), or trisomy 13 (median = 0.94 MoM), respectively. Neither in the control group nor in the group with trisomic fetuses was maternal serum alpha-fetoprotein significantly associated with fetal nuchal translucency thickness (r = 0.01 and r = 0.03).

CONCLUSION

Measurement of maternal serum alpha-fetoprotein concentration in the first trimester of pregnancy is not likely to be useful in the prediction of fetal trisomies.

Crown-rump length in chromosomally abnormal fetuses at 10 to 13 weeks' gestation

OBJECTIVE

Our purpose was to investigate whether fetuses with aneuploidies demonstrate evidence of growth retardation during the first trimester.

STUDY DESIGN

This was a retrospective, cross-sectional study of singleton pregnancies undergoing fetal karyotyping at 10 to 13 weeks' gestation. Measurements of crown-rump length in 135 chromosomally abnormal fetuses were compared with those in 700 chromosomally normal fetuses.

RESULTS

The median crown-rump length of fetuses with trisomy 18 (n = 32) was significantly reduced. In contrast, in fetuses with trisomy 21 (n = 72), trisomy 13 (n = 11), 47,XXX (n = 6), 47,XXY (n = 6), 45,X (n = 5), and triploidy (n = 3) the crown-rump length was not lower than normal.

CONCLUSION

At 10 to 13 weeks' gestation fetuses with trisomy 18 are growth retarded, whereas in trisomy 21, trisomy 13, and sex chromosome aneuploidy growth is normal.

Maternal serum pregnancy-associated plasma protein A and fetal nuchal translucency thickness for the prediction of fetal trisomies in early pregnancy

OBJECTIVE

To determine if the risk for fetal trisomies during the first trimester of pregnancy can be derived by combining data from maternal serum pregnancy-associated plasma protein A (PAPP-A) and fetal nuchal translucency thickness.

METHODS

Pregnancy-associated plasma protein A was measured in samples from 87 singleton pregnancies with fetal chromosomal abnormalities (45 trisomy 21, 19 trisomy 18, eight trisomy 13, 11 sex chromosome aneuploidies, four triploidies) and 348 chromosomally normal controls at 10-13 weeks' gestation. Likelihood ratios for trisomies 21, 18, and 13 in relation to PAPP-A, in multiples of the normal median (MoM) for crown-rump length, were derived from the overlapping gaussian frequency distribution curves for normal and abnormal pregnancies.

RESULTS

In the chromosomally normal group, maternal serum PAPP-A correlated significantly with fetal crown-rump length (r = 0.421, P < .0001). In the chromosomally abnormal group, the median PAPP-A was significantly lower than in the normal controls. The respective median values expressed in MoM for trisomies 21, 18, and 13 and other aneuploidies were 0.5 MoM (90% confidence interval [CI] 0.09-1.67, z = 6.0, P < .001), 0.17 MoM (90% CI 0.06-1.45, z = 6.6, P < .001), 0.25 MoM (90% CI 0.10-0.62, z = 4.5, P < .001), and 0.72 MoM (90% CI 0.09-2.48, z = 2.2, P < .05), respectively. There was no significant linear association between PAPP-A and fetal nuchal translucency thickness in either the chromosomally normal (r = -0.01, P = .89) or abnormal groups (r = -0.19, P = .08).

CONCLUSION

The risks for fetal trisomies at 10-13 weeks' gestation can be derived by combining data on maternal age, maternal serum PAPP-A, and fetal nuchal translucency thickness.