Association between selected structural defects and chromosomal abnormalities.

OBJECTIVE: To determine the association between some major structural abnormalities detected prenatally by ultrasound and chromosomal abnormalities. MATERIAL AND METHODS: The present study was a retrolective, transversal study. We analyzed case records of patients during the fetal follow-up at the Department of Maternal Fetal Medicine from January 1994 to May 2010 to identify fetal patients with a diagnosis of holoprosencephaly, diaphragmatic hernia, omphalocele, cystic hygroma, hydrops and cardiac defects. We analyzed patients who had a prenatal invasive diagnosis procedure to obtain the odds ratio (OR) for some major isolated anomalies and their different combinations with respect to chromosomal abnormalities. RESULTS: We examined 280 patients with ultrasonographic markers for chromosomal alteration, 197 met inclusion criteria, from which 88 had chromosomal abnormalities. The most frequent diagnosis was trisomy 18 (31.8%), which was followed by trisomy 21 (21.6%), trisomy 13 (21.6%), Turner syndrome (monosomy X) (14.8%) and other chromosomal abnormalities (10.2%). Among the fetuses with nonisolated holoprosencephaly, we obtained an OR of 4.9 95% CI (0.99-24.2) for aneuploidy. Associated omphalocele had an OR of 7.63 95% CI (2.07-46.75), p < 0.01. Interestingly, 62% of aneuploidy cases had associated cardiac defects [OR = 7.7 95% CI (1.4-41.7)]. In addition, associated cystic hygroma had an OR of 2.5 95% CI (0.59-10.91). Heart defects were the most common defects in fetuses with trisomy 18 (57.1%), when they were associated with facial cleft, we had an OR of 11.08 95% CI (2.99-41.11), p < 0.0001. Statistical potency was calculated for each analyzed defect and it was over 80% for all of them but diaphragmatic hernia. CONCLUSIONS: The association of 2 or more structural defects increased the probability of a fetus to be a carrier of a chromosomal disorder; however this was not statistically significative except for associated omphalocele. Heart defects showed the greatest association with all chromosomal abnormalities. The most important association was among heart defect, facial cleft and trisomy 13.

Prenatal prevalence of skeletal dysplasias and a proposal ultrasonographic diagnosis approach.

OBJECTIVE: To determine the prevalence of fetal bone dysplasias diagnosed at the Department of Maternal Fetal Medicine (UNIMEF) of the Instituto Nacional de Perinatologia (INPer); and to describe the most frequent skeletal dysplasias and to propose a diagnostic flow chart. MATERIALS AND METHODS: This is a case series study including skeletal dysplasias cases from January 1995 until December 2009 at the UNIMEF Statistical analysis was performed using SPSS 12 statistical software. RESULTS: A total of 81,892 births were registered at the institution during the study period. The prevalence of bone dysplasia was 8.1 per 10,000 births. We used a diagnostic flow chart that was developed at our institution to diagnose skeletal dysplasias. Micromelia (n = 40, 59.7%) and both rhizomelia and mesomelia (n = 17, 25.3%) were highly prevalent. We found other structural anomalies in 40 cases (61.1%), which were associated with different skeletal dysplasias; these other anomalies were mainly congenital heart diseases (12 cases) with a predominance of ventricular septal defects. There was polyhydramnios in 43.2% of cases. The mean of the gestational age at diagnosis was 24.5 weeks (SD 5.66). The karyotype was obtained in 11.9% (8/67) of cases. A total of 7 stillbirths and 11 neonatal deaths were registered, of which only 10 cases received a necropsy. Births occurred in the third trimester for 88% of cases, of which 85% were born via Cesarean section, whereas in the second trimester, the vaginal approach was chosen in 100% of cases. CONCLUSIONS: The prenatal diagnosis of bone dysplasias is challenging due to the late development of the diagnostic features. Nevertheless, using ultrasonography in a systematic approach, in conjunction with a multidisciplinary approach, is a key factor in the diagnosis of this disease during the fetal period.

Accuracy of different equations for estimating fetal weight.

OBJECTIVE: To evaluate the accuracy of ten equations based on ultrasound parameters for estimating fetal weight (FW). STUDY DESIGN: A cross-sectional study was performed in 250 healthy women with normal singleton pregnancies between 34 and 41 weeks of gestation. FW estimations calculated according to ten different equations were compared against birth weight (BW) which was determined within 72 h after FW estimation. Estimated error rate, intraclass correlation coefficient, and agreement between BW and FW calculated by each formula were analyzed. RESULTS: Most of the formulas were inaccurate in predicting BW, only 2 formulas showed less than 10% of the measurements lying within the 10% of estimated error. Four formulas tended to overestimate, while six tended to underestimate FW. CONCLUSIONS: Appropriate equations for estimating FW in all populations should be developed. However, where there are no local growth curves, the accuracy of the available fetal growth equations should be tested.

Changes in central and peripheral circulation in intrauterine growth-restricted fetuses at different stages of umbilical artery flow deterioration: new fetal cardiac and brain parameters.

OBJECTIVE: To evaluate changes in central and peripheral circulation, including new and standard parameters of the fetal brain and heart in fetuses with intrauterine growth restriction (IUGR) in relation to progressive deterioration of the umbilical artery (UA). METHODS: Seventy-two IUGR fetuses were studied longitudinally. IUGR was defined as an estimated fetal weight <10th centile for gestational age. Fetuses were classified according the UA pulsatility index (PI) as: group 1, normal UA-PI (<95th centile; <1.645 z-scores), group 2, UA-PI (≥95th centile and <99th centile; ≥1.645 and <3 z-scores), group 3, UA absent end-diastolic flow, and group 4, UA reversed end-diastolic flow. Middle cerebral artery (MCA), anterior cerebral artery segments 1 (ACA1) and 2 (ACA2), aortic isthmus blood flow index (IFI), modified myocardial performance index (Mod-MPI), ductus venosus (DV), renal artery (RA), femoral artery (FA) and amniotic fluid index (AFI) were weekly evaluated until delivery. RESULTS: A total of 263 scans were performed (median, 3 (range: 1-23) per patient). There were 6 intrauterine and 2 neonatal deaths. Although all cerebral arteries showed a reduction in the PI, ACA1 showed the earliest vasodilatation. From group 2 onwards, all cerebral vessels had a similar pattern of vasodilatation. Mod-MPI became abnormal at group 1 with no further changes. IFI and DV became constantly abnormal starting from group 2. No changes in the RA-PI or FA-PI were documented. CONCLUSION: The process of hemodynamic deterioration in IUGR fetuses seems to be earlier represented by the ACA1 and the Mod-MPI. Signs of further deterioration were observed in the DV, IFI and MCA. The peripheral blood in the RA and FA did not show any change. AFI showed a late deterioration process.

Cerebral venous blood flow in growth restricted fetuses with an abnormal blood flow in the umbilical artery before 32 weeks of gestation.

OBJECTIVE: To evaluate the brain venous circulation in fetuses with severe intrauterine growth restriction (IUGR) before 32 weeks of gestation. STUDY DESIGN: Fifty fetuses with severe IUGR diagnosed between 27 and 32 weeks of gestation and 50 appropriate-for-gestational age (AGA) fetuses matched by gestational age were evaluated. IUGR fetuses were classified according to their hemodynamic deterioration pattern in relation to the Doppler examination of the umbilical artery (UA), middle cerebral artery (MCA) and ductus venosus (DV). The fetal venous brain blood flow was evaluated in the vein of Galen (VG), superior sagittal (SS), straight and transverse venous sinuses. RESULTS: Only the transverse sinus (TS) showed a significant reduction in the pulsatility index (PI) values in IUGR fetuses. All other veins showed similar PI values between IUGR and AGA fetuses. All cerebral veins of IUGR fetuses showed significantly increased maximum and mean velocities. All these findings did not change in relation to the hemodynamic IUGR deterioration. In nearly all normal and all IUGR fetuses, a pulsatile blood flow pattern was observed in the straight and transverse sinuses, whereas an increased pulsatile pattern in the VG and in the SS was noted in IUGR fetuses. CONCLUSION: Brain venous blood flow in IUGR fetuses shows an increment in the maximum and mean velocities of all veins and a reduction in the PI in the transverse sinus.