[Combination of the computerized analysis of fetal heart rate and amniotic fluid index in the prediction of neonatal acidemia: a modified biophysical profile]

OBJECTIVE

To study the use of a modification of the classical biophysical profile by the combination of computerized analysis of fetal heart rate (cCTG) and the amniotic fluid index (AFI) in the prediction of neonatal acidemia at birth.

METHODS

We considered 89 singleton third trimester high risk pregnancies delivered by cesarean section, with an AFI evaluated within 24 hrs from birth, and an antepartum cCTG performed within 6 hrs from delivery. We assigned values for AFI (oligo/anhydramnios = 1, normal = 0) and cCTG (Dawes-Redman criteria, not satisfied = 1, satisfied = 0). The endpoint was to predict an abnormal neonatal outcome as defined by an umbilical artery (UA) pH < or = 7.2.

RESULTS

Fifteen neonates presented an UA pH < or = 7.2. By performing a logistic regression, we found that cCTG + AFI score (abnormal value 1-2) was able to significantly predict a pH value (< or = 7.20) with an Odds Ratio = 2.83 (p < 0.02). The diagnostic accuracy of the combination of cCTG + AFI was as follows: sensitivity: 80%, specificity: 58%.

COMMENT

We suggest that the combination of cCTG + AFI included in the simple score we propose, may be of value in the prediction of neonatal acidemia and help in the management of third trimester high risk pregnancies.

[Fetal lung maturity and fetal flowmetry changes]

OBJECTIVE

To verify whether in high risk pregnancies, fetuses with altered Doppler flow velocimetry waveforms (FVW) are associated with both biochemical and/or biophysical changes in the amniotic fluid (AF) lung surfactant.

MATERIALS AND METHODS

Hundred-eight high risk pregnancies were considered on the basis of a complete Doppler velocimetry study performed within 24 hrs before amniocentesis and delivery within 1 week from amniocentesis. From this group, 22 pregnancies were recruited as altered FVW cases on the basis of simultaneous alteration of Umbilical Artery Pulsatility Index (UA PI), and UA PI/MCA PI (Middle Cerebral Artery Pulsatility Index) ratio (UA/MCA); in all altered FVW group cases the Mean Uterine Artery Resistance Index (Ut RI) was also altered. Amniotic fluid samples obtained by ultrasound guided amniocentesis were analysed for FLM within 24 hours from collection. Pulmonary maturity was determined by planimetric lecithin/sphingomyelin ratio (L/S), phosphatidylglycerol (PG) and the lamellar bodies count (LBs).

RESULTS

When FLM parameters were regressed versus FVW in the whole study group, we found a significant negative correlation between UA/MCA and L/S (r = -0.19, p < 0.05). No significant correlations were found between FVW indices and LBs. When we compared FLM parameters for gestational age subgroups (23-32 wks, > 33 wks), L/S values were significantly higher in patients with normal FVW indices in comparison to pathologic FVW pregnancies for gestational ages > 33 wks. This was reflected by a negativè correlation between FVW and FLM (UA/MCA vs. L/S r = -0.54, p < 0.02; UA/MCA vs. PG, r = -0.60, p < 0.01).

COMMENT

Our data suggest that fetuses with an UA/MCA ratio > 95 degrees are not protected from neonatal RDS, as usually felt, but show a delay in FLM, particularly in pregnancies > 33 wks.

[Fetal lung maturity in biamniotic twin pregnancy]

OBJECTIVE

To assess the need to perform amniocentesis for the evaluation of fetal lung maturity (FLM) in both amniotic sacs of twin pregnancies.

STUDY DESIGN

A retrospective study. We considered 33 twin biamniotic pregnancies, delivering within 1 week from amniocentesis. FLM testing was performed by planimetric lecithin/sphingomyelin ratio (L/S), and lamellar bodies count (LB) according to our methodology.

RESULTS

A strong correlation was found between L/S (p < 0.001, r = 0.59) and LB (p < 0.001, r = 0.69) values between smaller and larger twins. No significant regression was found between differences of L/S and LB among both amniotic sacs against gestational age. When stratifying FLM values < 34 and > 34 wks' gestation, again no difference was found in mean difference of L/S and LB before and after 34 wks.

CONCLUSIONS

FLM should not be assessed in both amniotic sacs at any gestational age independent of weight and/or sex of the conceptus.

A five-year experience with fragile X testing. Setting laboratory standards of practice and a cost-effective protocol

During the years 1990-1994, our center tested 652 patients, with a broad range of referral indications, for fragile X syndrome using either cytogenetic analysis alone (Protocol 1) or more recently, a combination of DNA analysis and routine karyotyping (protocol 2). The overall positive rate for fragile X was 3.1% with an incidence of other chromosomal abnormalities (OCAs) of 3.2%. Breakdown of cases using each testing protocol along with percent positives is: [table: see text] Use of Protocol 2 yielded only definitive fragile X results, while more than half of the "positives" using Protocol 1 were equivocal. Historically this has been problematic for both the laboratory and physician since interpretation is often dependent on an equally equivocal clinical picture. Protocol 2 eliminates these diagnostic dilemmas without compromising detection of other chromosomal abnormalities, the incidence of which appears to be unaffected by testing method used. The overall incidence of OCA of 3.2% underscores the value of routine karyotyping in this referral group and likely reflects the phenotypic variability of fragile X and its clinical overlap with other chromosomal abnormalities. We believe that a fragile X testing protocol combining routine karyotyping with definitive molecular technology represents the most cost-effective diagnostic approach to this clinically challenging patient population.

Evaluation of the effectiveness of a teratogen information service: a survey of patient and professional satisfaction

We have evaluated the effectiveness of the Wisconsin Teratogen Project (WTP), a teratogen information service, using two retrospective surveys. We surveyed medical professionals who utilized the WTP and patients who had received teratogen counseling in a clinic setting. The results from the medical professional survey indicated that medical professionals rely on the WTP for accurate and convenient teratogen information. A tendency to rely on the Physician's Desk Reference as an alternative resource was noted, reinforcing the need to encourage professionals to use teratogen information service projects. Major findings and conclusions from the patient survey included: patients found counseling to be most helpful if, whenever possible, numeric risks were provided; recommendations made in the absence of known risk were not considered by patients to be helpful for providing reassurance; overall compliance with recommendations was high but behavioral recommendations seemed to reduce reassurance and increase dissatisfaction with the service for some patients; and pregnant women exposed to low-dose ionizing radiation were more likely to have considered termination of pregnancy prior to referral but were not more likely to terminate following counseling. Our findings suggest that although the WTP is considered an effective service overall, teratogen counselors should give special consideration to patient and counseling characteristics as these can significantly influence the perception of the risk counseling provided. Particular attention should be given to patients with low-dose ionizing radiation exposure, since misperception of its teratogenic risk is extremely common.