Dilemmas in the management of twins discordant for anencephaly diagnosed at 11 + 0 to 13 + 6 weeks of gestation.

OBJECTIVE: To help develop an evidence-based approach to the best management of twin pregnancies discordant for anencephaly. METHODS: We retrospectively examined the management and outcome of 18 pregnancies discordant for anencephaly diagnosed at 11 + 0 to 13 + 6 weeks of gestation in our center. We combined these data with those from other publications. In total, there were 44 dichorionic pregnancies that were managed expectantly (n = 35) or by selective feticide (n = 9) and 19 monochorionic pregnancies that were managed expectantly. We also reviewed the literature to ascertain the outcome of monochorionic twin pregnancies undergoing cord occlusion. RESULTS: In the 35 dichorionic pregnancies that were managed expectantly, 20 (57.1%) developed polyhydramnios at 25-31 weeks; 13 were managed expectantly, five had amniodrainage and two had selective feticide. In 34 of the 35 cases the non-anencephalic twin was liveborn at a median gestation of 36 (range, 28-39) weeks and in six (17.6%) of these it was born before 33 weeks. In the dichorionic pregnancies that had selective feticide, there was one miscarriage and eight (88.9%) live births at a median gestation of 37 (range, 30-40) weeks and in one (12.5%) of these it was born before 33 weeks. In the monochorionic pregnancies, four (21.1%) anencephalic fetuses died at 20-32 weeks and in three of these the normal co-twin also died. In the 16 (84.2%) cases resulting in the live birth of the normal twin, delivery occurred at a median gestation of 33 (range, 27-39) weeks and in six (37.5%) of these it was before 33 weeks. Ultrasound-guided bipolar cord coagulation in 92 pregnancies, mostly complicated by twin reversed arterial perfusion sequence or severe twin-to-twin transfusion syndrome, was associated with a survival rate of 77.2% and early preterm delivery rate of 31.0%. CONCLUSION: Dichorionic twins discordant for anencephaly are best managed with serial ultrasound examinations for early diagnosis of polyhydramnios, which can then be treated either by amniodrainage or selective feticide. In monochorionic twins it is uncertain whether the best management is expectant or by cord occlusion.

Assessment of lung area in normal fetuses at 12-32 weeks.

OBJECTIVE: To establish reference intervals with gestation for the right and left lung areas and lung area to head circumference ratio (LHR). METHODS: This was a cross-sectional study of 650 normal singleton pregnancies at 12-32 weeks of gestation. We measured the left and right lung areas on the cross-sectional plane of the thorax, used for examination of the four-chamber view of the heart, by three different techniques: firstly, manual tracing of the limits of the lungs; secondly, multiplication of the longest diameter of the lung by its longest perpendicular diameter; thirdly, multiplication of the anteroposterior diameter of the lung at the mid-clavicular line by the perpendicular diameter at the midpoint of the anteroposterior diameter. RESULTS: The respective mean left and right lung areas (manual tracing) increased with gestational age, from 36 and 58 mm(2) at 12 weeks to 220 and 325 mm(2) at 20 weeks and 594 and 885 mm(2) at 32 weeks. This 16-fold increase in lung area was accompanied by a four-fold increase in head circumference. Consequently, the left and right LHR increased with gestational age. The most reproducible way of measuring the lung area was by manual tracing of the limits of the lungs and the least reproducible was by multiplying the longest diameter of the lungs by their longest perpendicular diameter. Furthermore, the method employing the longest diameter, compared with the tracing method, overestimated both the left and the right lung areas by about 45% and the method employing the anteroposterior diameter overestimated the area of the right lung by about 35%, but not that of the left lung. CONCLUSIONS: In the antenatal prediction of pulmonary hypoplasia by the assessment of lung area it is important to take gestational age into account. Dividing the lung area by the head circumference does not correct for the gestation-related increase in lung area. Reproducible measurement of the lung area is provided by manual tracing of the limits of the lungs, rather than by multiplication of lung diameters.

Coelomic fluid leptin concentration in normal first-trimester pregnancies and missed miscarriages.

OBJECTIVE: Investigation of the possible role of leptin in early pregnancy failure. METHODS: Leptin concentration was measured in maternal serum, coelomic fluid and amniotic fluid from 15 singleton pregnancies with live fetuses and 7 missed miscarriages at 7-10 weeks of gestation. RESULTS: In the pregnancies with live fetuses, the median leptin concentration was significantly higher in coelomic fluid (median 33.1 ng/ml) than in maternal serum (median 8.1 ng/ml) or amniotic fluid (median 0.5 ng/ml). In the pregnancies with missed miscarriage, compared to those with live fetuses, the median leptin concentration in coelomic fluid was higher (median 45.3 ng/ml), but in maternal serum it was not significantly different (median 5.5 ng/ml). CONCLUSIONS: The high coelomic fluid leptin concentration suggests that embryonic death may be preceded by impaired oxygenation of the placenta that stimulates production of leptin.

Screening for trisomy 21 in monochorionic twins by measurement of fetal nuchal translucency thickness.

OBJECTIVE: To determine whether in screening for trisomy 21 by measurement of fetal nuchal translucency (NT) thickness in monochorionic twin pregnancies it is preferable to use the higher, smaller or average NT. METHODS: We retrospectively examined 769 monochorionic twin pregnancies that had undergone NT screening. The selection criteria were that first, in each pregnancy both fetuses were alive at the 11 to 13 + 6-week scan and second, the fetal karyotype had been determined by prenatal invasive testing or the pregnancy outcome was known. In each pregnancy the risk for trisomy 21 was calculated by a combination of maternal age and fetal NT for crown-rump length (CRL). Three estimates of risk for each pregnancy were made using the higher, smaller and average NT and these were compared for detection and false positive rates. RESULTS: The median maternal age was 33 (range, 16-45) years, the CRL was 62 (range, 45-84) mm and gestational age was 12 (range, 11 to 13 + 6) weeks. Either the fetal karyotype was normal, or phenotypically normal babies were born, in 761 cases. The karyotype was abnormal in eight cases, including six with trisomy 21. The estimated risk using the higher, smaller and average NT was 1 in 300 or more in 6 (100%), 4 (66.7%) and 6 (100%) of the trisomy 21 pregnancies and in 148 (19.4%), 57 (7.5%) and 106 (13.9%) of the normal pregnancies. For a detection rate of 100%, the false positive rates using the higher, smaller and average NT would be 5.1%, 45.9% and 4.2%, respectively. CONCLUSION: In monochorionic twins, effective screening for trisomy 21 is best provided by using the average NT measured in the two fetuses.

Likelihood ratio for trisomy 21 in fetuses with absent nasal bone at the 11-14-week scan.

OBJECTIVE: To update the likelihood ratio for trisomy 21 in fetuses with absent nasal bone at the 11-14-week scan. METHODS: Ultrasound examination of the fetal profile was carried out and the presence or absence of the nasal bone was noted immediately before karyotyping in 5918 fetuses at 11 to 13+6 weeks. Logistic regression analysis was used to examine the effect of maternal ethnic origin and fetal crown-rump length (CRL) and nuchal translucency (NT) on the incidence of absent nasal bone in the chromosomally normal and trisomy 21 fetuses. RESULTS: The fetal profile was successfully examined in 5851 (98.9%) cases. In 5223/5851 cases the fetal karyotype was normal and in 628 cases it was abnormal. In the chromosomally normal group the incidence of absent nasal bone was related first to the ethnic origin of the mother, being 2.2% for Caucasians, 9.0% for Afro-Caribbeans and 5.0% for Asians; second to fetal CRL, being 4.7% for CRL of 45-54 mm, 3.4% for CRL of 55-64 mm, 1.4% for CRL of 65-74 mm and 1% for CRL of 75-84 mm; and third to NT, being 1.6% for NT < or = 95th centile, 2.7% for NT > 95th centile-3.4 mm, 5.4% for NT 3.5-4.4 mm, 6% for NT 4.5-5.4 mm and 15% for NT > or = 5.5 mm. In the chromosomally abnormal group there was absent nasal bone in 229/333 (68.8%) cases with trisomy 21 and in 95/295 (32.2%) cases with other chromosomal defects. Logistic regression analysis demonstrated that in the chromosomally normal fetuses significant independent prediction of the likelihood of absent nasal bone was provided by CRL, NT and Afro-Caribbean ethnic group, and in the trisomy 21 fetuses by CRL and NT. The likelihood ratio for trisomy 21 for absent nasal bone was derived by dividing the likelihood in trisomy 21 by that in normal fetuses. CONCLUSION: At the 11-14-week scan the incidence of absent nasal bone is related to the presence or absence of chromosomal defects, CRL, NT and ethnic origin.

Assessment of the fetal nasal bone at 11-14 weeks of gestation by three-dimensional ultrasound.

OBJECTIVE: To evaluate the benefit of three-dimensional (3D) ultrasound in the examination of the fetal nasal bone at 11-14 weeks of gestation. METHOD: We examined the fetal nasal bone in 120 stored volumes acquired transabdominally with a 3D scanner from singleton pregnancies at 11-14 weeks of gestation. The volume acquisition had been performed following conventional ultrasound examination that had demonstrated presence of the fetal nasal bone. The volumes were obtained with two-dimensional (2D) start images in transverse, coronal mid-sagittal, parasagittal and oblique longitudinal sections of the fetal head. RESULTS: In the transverse and coronal sections, a satisfactory image demonstrating presence of the nasal bone was achieved in only three and one, respectively, of the 20 volumes that we obtained. In mid-sagittal sections, the nasal bone was always visible when the angle was within a range of 30-60 degrees, without the need for sectional image analysis. None of the images with an angle >60 degrees or <30 degrees was satisfactory. In the parasagittal sections with the fetal profile at 45 degrees, a good-quality image of the nasal bone was possible in all cases that were examined, irrespective of the distance from the mid-sagittal plane. In the oblique longitudinal sections with the fetal profile at 45 degrees, there were 10 volumes where the 2D start section was at 0-25 degrees from the midline and in all these cases the nasal bone was successfully visualized. In contrast, only 5/20 cases where the 2D start section was at 25-90 degrees from the midline provided a satisfactory image demonstrating the nasal bone. In 5/10 volumes obtained with the fetus facing downwards the nasal bone was visible in both the 2D and 3D images. CONCLUSION: In a 3D volume the extent to which the nasal bone can be demonstrated to be present in a given reconstructed section is entirely dependent on obtaining a good initial 2D view.

Umbilical endometriosis after unprotected removal of uterine pieces through the umbilicus.

We reviewed the frequency of umbilical endometriosis after laparoscopic-assisted subtotal hysterectomy with unprotected removal of uterine segments through the umbilical incision. Retrospective analysis of surgical records was followed by recall and clinical examination of 10 patients. Two women developed umbilical endometriosis. One was the only patient operated during menstruation. The other was one of two women operated in the late luteal phase and with subsequent adequate exposure to endogenous or exogenous estrogens. From 1976-1997, 22 reports of umbilical endometriosis were published: 18 cases were spontaneous, 2 occurred after ring sterilization, and 2 after diagnostic laparoscopy. These data lend support to the concept that implantation and the potential development of menstrual endometrium are increased after surgery. It is speculated that procedures that expose menstrual endometrial cells to nonepithelialized areas could be associated with an increased risk of endometriosis.