Cystic hygroma detected in the first trimester scan in Hong Kong.

OBJECTIVE: To investigate the outcome of fetuses with cystic hygroma (CH) diagnosed at the first trimester from a general population in Hong Kong. METHOD: This was a prospective study of 30 fetal cystic hygroma detected at 11 to 13 + 6 weeks' gestation in 8835 sequential unselected pregnancies. Fetal cystic hygroma was categorized as isolated cystic hygroma (ICH) or associated cystic hygroma (ACH) according to the presence of associated multiple congenital structural abnormalities (MCA). RESULTS: There were 10 cases of ICH and 20 cases of ACH. The karyotypes were obtained in 29 cases. In the ICH, 30% (3/10) were associated with chromosomal abnormalities. In the ACH, 65% (13/20) were associated with major chromosomal abnormalities. CONCLUSION: This study suggests that the prognosis of cystic hygroma detected in the first trimester is guarded, with high incidence of MCA (66.7%, 20/30) and chromosomal abnormalities (53.3%, 16/30). The findings support detailed ultrasound examination and invasive prenatal diagnosis for cystic hygroma.

The effect of volume of chorionic villi on long-term cell culture.

OBJECTIVE: It was the aim of our study to investigate the association between culture time and weight of villi obtained by transabdominal chorionic villus sampling (CVS). METHODS: We analyzed 1,442 villus samples. RESULTS: The gestational age at sampling ranged from 10 to 14 weeks. The weight of villi in these samples ranged from 1 to 80 mg (median 10 mg, interquatile range 7-12 mg). The culture time ranged from 5 to 24 days. Culture time was significantly and inversely correlated with the weight of villi obtained (r = -0.258, p < 0.01). Time was significantly longer when 5 mg or less of villi was obtained but the difference was only up to 2 days. CONCLUSIONS: Because the difference in culture time for different groups of villus samples was within 1-2 days, this relationship is statistically significant but has no clinical significance.

First-trimester fetal limb biometry in Chinese population.

OBJECTIVES: To establish reference ranges for fetal limb biometry obtained by transabdominal ultrasound examination at 12-14 weeks of gestation in Chinese women. METHODS: A total of 1489 normal singleton fetuses between 12(+0) and 14(+6) weeks of gestation were examined transabdominally by two experienced observers. The gestation was ascertained by measurement of fetal crown-rump length (CRL) or biparietal diameter (BPD) and head circumference (HC). The lengths of the humerus and femur were prospectively worked out. RESULTS: Gestation-specific reference ranges for limb measurements were calculated. The femur length (FL) (mean +/- SD) was 9.15 +/- 1.44 mm at 12-12(+6) weeks, 11.45 +/- 1.35 mm at 13-13(+6) weeks, and 13.64 +/- 1.60 mm at 14-14(+6) weeks; the corresponding humerus length (HL) (mean +/- SD) was 9.63 +/- 1.44 mm, 12.01 +/- 1.41 mm, 14.29 +/- 1.48 mm, respectively. CONCLUSIONS: There was a general increase in fetal limb biometry with gestation. Fetal limb length can be an early marker of early growth restriction as well as fetal skeletal dysplasia among women in the local population.

Maternal serum pregnancy-associated plasma protein-A and free beta-human chorionic gonadotrophin in pregnancies conceived with fresh and frozen-thawed embryos from in vitro fertilization and intracytoplasmic sperm injection.

OBJECTIVE: Maternal serum pregnancy-associated plasma protein-A (PAPP-A) and free beta-human chorionic gonadotrophin (beta-hCG) are useful markers in the screening of Down syndrome in the first trimester. We investigated the effect of intracytoplasmic sperm injection (ICSI), freezing and thawing of embryos on the levels of these two analytes in assisted reproduction pregnancies. METHODS: We recruited 149 women who conceived after assisted reproduction with fresh embryos (92 from conventional IVF and 57 from ICSI), 85 women who conceived with frozen-thawed embryos (54 from conventional IVF and 31 from ICSI) and 401 women with spontaneous conceptions as controls. The concentrations of PAPP-A and free beta-hCG were measured between 10 and 14 weeks and were converted to multiples of medians (MoM) for comparisons. RESULTS: Median PAPP-A MoMs were significantly reduced in ICSI pregnancies in the fresh and frozen-thawed embryo subgroups (0.70 and 0.66 MoM respectively) and in the IVF fresh embryo subgroups (0.83 MoM), as compared to controls (1.00 MoM). Free beta-hCG MoM was significantly reduced in the IVF fresh embryos subgroup (0.87 MoM), but not in the other three subgroups. CONCLUSION: Further studies for exploring the underlying pathophysiology and adjustment in the marker levels for screening of Down syndrome are warranted in pregnancies conceived after assisted reproduction.

Ultrasound screening of fetal structural abnormalities at 12 to 14 weeks in Hong Kong.

OBJECTIVE: Ultrasound screening for fetal abnormalities is conventionally performed at 18 to 20 weeks of gestation. Recent data suggested that many fetal structural abnormalities could be detected by ultrasound examination at 12 to 14 weeks of pregnancy. In this study, we investigated the effectiveness of early ultrasound examination in the detection of fetal abnormalities in women aged 35 years or older. METHODS: From February 1998 to March 2001, pregnant women aged 35 or above were examined by transabdominal and transvaginal sonography between 12 and 14 weeks of gestation. If the anatomical survey was normal, the women underwent routine 16- to 20-week ultrasound examination. Pregnancy outcome was obtained from the hospital records or by contacting the subjects. RESULTS: Twenty-six of the 1609 fetuses had structural abnormalities. Fourteen were detected at the ultrasound examination at 12 to 14 weeks. Detection rate was 53.8% (14/26; 95% CI 44, 64) with a false-positive rate of 0.3% (5/1583; 95% CI 0.16, 0.44). Six additional abnormalities (23.1%, 6/26) were detected at 16- to 20-week ultrasound examination. The overall detection rate of structural abnormalities was 76.9% (20/26; 95% CI 68.6, 85.2). CONCLUSIONS: The effectiveness of ultrasound examination at 12 to 14 weeks to screen for fetal abnormalities approached that achieved at 20 weeks and can be a good adjunct to the conventional examination.

Sonographic features of ileal duplication cyst at 12 weeks.

Enteric duplication cyst is a congenital abnormality that is believed to arise from abnormal recanalization of the bowel during embryogenesis. Previous reports suggest that the condition may be suspected prenatally by sonographic demonstration of an intra-abdominal cystic mass in the second and third trimesters. We present the sonographic features of a fetus with ileal duplication cyst at 12 weeks of gestation, which show that the condition may present in the first trimester of pregnancy.

Comparison and integration of first trimester fetal nuchal translucency and second trimester maternal serum screening for fetal Down syndrome.

BACKGROUND: It is uncertain whether first trimester nuchal translucency (NT) is more effective than the well-established second trimester serum screening for fetal Down syndrome or whether their combination works best. We report data from a large multicentre non-interventional trial in which all subjects underwent both first and second trimester screening. METHODS: All women who attended the obstetric clinic before 15 weeks' gestation were recruited. An ultrasound examination was performed at 10 to 14 weeks to measure the NT. The nuchal measurements were not acted upon unless the fetus showed gross features of hydrops fetalis. All women had serum alpha-fetoprotein (AFP) and human chorionic gonadotrophin (hCG) assay at 15 to 20 weeks. The Down syndrome risk assigned by serum screening was disclosed and amniocentesis was offered if this assigned risk was >or=1:250 or if the women were 35 years and older. The efficacy of different combinations of screening markers was compared. RESULTS: Between January 1997 and August 2000, 17 590 women were recruited (19% >or=35 years old). After excluding subjects who miscarried, defaulted the serum test and other reasons, 16 237 pregnancies were analysed. Of these, 35 pregnancies were affected by Down syndrome (2.2 cases per 1000 pregnancies). At a false-positive rate of 5%, the detection rate of Down syndrome by NT alone, NT and age, serum hCG, AFP and age, and NT, hCG, AFP and age were 61%, 69%, 73% and 86%, respectively. CONCLUSION: Integration of NT and second trimester serum AFP and hCG assay yielded the best screening efficacy for Down syndrome.

Attitude of at-risk subjects towards preimplantation genetic diagnosis of alpha- and beta-thalassaemias in Hong Kong.

OBJECTIVES: The aim of the study was to assess whether preimplantation genetic diagnosis (PGD) was an acceptable alternative to prenatal diagnosis in couples at risk of giving birth to a child with alpha- or beta-thalassaemia in an Asian population. METHODS: An information leaflet was distributed to the women at risk. They were asked to complete a questionnaire after having an interview with a designated investigator. RESULTS: A total of 141 valid questionnaires were analysed; 82.3% of the women considered PGD either the same or better than conventional prenatal diagnosis. Women with an affected child or a subfertility problem were more willing to accept PGD and to undergo this procedure in their future pregnancies. Their main concern about PGD was damage to the embryo during the PGD procedure. The most important perceived advantage of PGD was avoidance of termination of an affected pregnancy. CONCLUSIONS: PGD is an acceptable alternative to conventional prenatal diagnosis in women at risk of giving birth to a child with alpha- or beta-thalassaemia in an Asian population. This is particularly true in women with a subfertility problem and in women who already have an affected child.

The effect of ethnic origin on nuchal translucency at 10-14 weeks of gestation.

INTRODUCTION: Fetal nuchal translucency (NT) increases with gestation and is affected by fetal posture and fetal gender. A recent report suggested that there might also be ethnic differences. We investigated the effect of ethnic origin on NT in an Asian population. METHODS: NT was measured at 10-14 weeks. The measurements were converted into multiples of the median (MoM) for gestational day. The risk of Down syndrome was calculated by combining NT and maternal age. Cases affected by chromosomal and major structural abnormalities were excluded. NT measurements of different ethnic groups were compared. RESULTS: Between January 1997 and October 2001, 16 981 pregnancies with known ethnic origin and normal fetal outcome were analysed. Median NT MoM (95% CI) of the Filipinos was 1.07 (1.04-1.11). This was significantly higher than that of the Chinese, 1.01 (1.01-1.02); other Asians (Indians, Pakistanis and Nepalese), 0.96 (0.94-0.99), and Caucasians, 0.98 (0.93-1.06) (p<0.05, respectively; Mann-Whitney U-test). An NT risk cut-off of 1:180 would classify 5% of the Chinese, 4.6% of the Caucasians, 5.6% of the Filipinos and 4.2% of the other Asians as screen-positive. There were no statistically significant differences between these screen-positive rates (p>0.05, Chi-square test). CONCLUSIONS: Although there were statistically significant differences in NT measurements between different ethnic groups, it was clinically insignificant, as reflected by similar screen-positive rates.

The effect of fast reporting by amnio-PCR on anxiety levels in women with positive biochemical screening for Down syndrome--a randomized controlled trial.

OBJECTIVE: To study the effect of fast reporting by polymerase chain reaction on amniotic fluid cells (amnio-PCR) on anxiety levels in women with positive biochemical screening for Down syndrome. METHOD: Between May 2000 and April 2001, 60 screen-positive women were randomized before amniocentesis into either having (group A) or not having (group B) fast-reporting by amnio-PCR. Anxiety levels were measured by the Spielberger State-Trait Anxiety Inventory just prior to amniocentesis, three days (when PCR results were known to group A) and three weeks (when standard karyotype results were known to both groups) afterwards. RESULTS: Two women were excluded because in one woman amnio-PCR showed trisomy 21 and the other miscarried shortly after amniocentesis. The state-anxiety scores increased over the three-week period after being informed of the positive-screen result in both groups. The trait- and state-anxiety scores at all points did not differ between the two groups. CONCLUSIONS: In contrast to the general belief, fast reporting by amnio-PCR did not alleviate anxiety in women who are screen-positive for Down syndrome.

Thermocoagulation of fetal sacrococcygeal teratoma.

Fetal sacrococcygeal teratoma can lead to a high output cardiac failure resulting in hydrops fetalis. One of the prenatal therapeutic options is to occlude the feeding vessels by radiofrequency ablation. We present a case of fetal sacrococcygeal teratoma diagnosed at 13 weeks of gestation. The tumour increased in size more than 100 fold over 5 weeks causing polyhydramnios and cardiac and placental enlargement. Thermocoagulation was performed at 18 weeks' gestation by passing an insulated electric wire through an 18 gauge needle placed close to the feeding vessels of the tumour at its neck. Blood supply to the tumour was successfully reduced. However, fetal death was diagnosed 2 days after the procedure. We speculate that it may be safer to limit the extent of coagulation in one attempt but to repeat the procedure at a later stage when necessary.

Middle cerebral artery Doppler study in fetuses with homozygous alpha-thalassaemia-1 at 12-13 weeks of gestation.

OBJECTIVE: Fetuses affected by homozygous alpha-thalassaemia-1 are anaemic from the first trimester of pregnancy. We investigated middle cerebral artery Doppler velocimetry in these affected fetuses at 12-13 weeks of gestation to assess its use in predicting fetal anaemia. METHODS: Women referred for the prenatal diagnosis of homozygous alpha-thalassaemia-1 before 14 weeks of gestation were recruited. All fetuses underwent pulsed Doppler examinations following colour flow mapping at 12 or 13 weeks of gestation. Homozygous alpha-thalassaemia-1 was diagnosed by DNA or haemoglobin study. The middle cerebral artery Doppler indices were compared between the affected fetuses and fetuses unaffected by homozygous alpha-thalassaemia-1. RESULTS: Between 1998 and 2000, 80 eligible women were recruited. Of these, 19 fetuses were affected by homozygous alpha-thalassaemia-1. Two of them showed hydropic changes at the time of Doppler study. The affected fetuses had significantly higher middle cerebral artery peak systolic velocity (V(max)) (36% increase) and time-averaged maximum velocity (V(tamx)) (33% increase). CONCLUSION: The increase of cerebral blood flow in affected fetuses is consistent with our previous finding of an increased forward flow in the ductus venosus, cardiac dilatation and an increase of cardiac output to preferentially shunt more oxygenated blood to the brain as a compensatory mechanism. However, extensive overlap of the middle cerebral artery flow velocity values between affected and unaffected fetuses precludes its use in predicting anaemia at 12-13 weeks' gestation.