Biomedical subjects

D M Wass

Publications and source records attributed to D M Wass.

7 recordsLinked to original sources

PubMed1997

A cohort study of pregnancy outcome after amniocentesis in twin pregnancy.

We conducted a retrospective cohort study to assess the risk of amniocentesis in twin pregnancy for adverse outcomes. The study base consisted of women who had an amniocentesis performed during twin pregnancy and a comparison representative sample of women who carried a twin pregnancy, but did not have invasive prenatal diagnosis. The 227 women in each of the exposed and non-exposed groups were residents of the state of New South Wales, Australia, over the period 1980-92, and were matched on maternal age and period of the infant's birth. Nearly 10% of twin pregnancies among the women having an amniocentesis were affected by a stillbirth, and the stillbirth rate among exposed fetuses (5.3%) was nearly twice as high as among non-exposed fetuses (3.1%). After adjustment for confounding and excluding abnormalities, there was a non-significant elevated relative risk of stillbirth after exposure to amniocentesis. The analysis by type of amniocentesis (with and without methylene blue dye) was limited by small numbers, but the burden of risk was primarily among women who had dye exposure during amniocentesis (relative risk = 3.64, 95% confidence interval = 1.15, 11.48). This increase remained after adjusting for confounding, although the confidence interval was wide. In conclusion, we were unable to establish with certainty whether an increased risk of stillbirth could be ruled out among women who had any type of amniocentesis in twin pregnancy.

Adult↗

PubMed1996

Fetal death after exposure to methylene blue dye during mid-trimester amniocentesis in twin pregnancy.

Methylene blue dye use during mid-trimester amniocentesis in twin pregnancy is associated with a high risk of small intestinal atresia. It is plausible that the effects of methylene blue as a fetotoxic agent may also lead to fetal death. We conducted a retrospective cohort study of all women who had an amniocentesis during twin pregnancy from 1980 through 1991 in New South Wales, Australia. Women who were exposed to methylene blue dye during the procedure were compared with women who had amniocentesis without dye exposure. Fetal death occurred in 31.8 per cent of pregnancies that had exposure to a high concentration of methylene blue, compared with 14.5 per cent of pregnancies exposed to a low concentration and 4.3 per cent of pregnancies with no exposure to dye. The unadjusted and adjusted risks and 95 per cent confidence intervals (CIs) for fetal death after any exposure to dye were 5.03 (2.12-11.91) and 8.52 (2.28-31.80), respectively. The adjusted odds ratio and 95 per cent CIs for the low and high concentration dye solutions were 4.63 (0.93-23.13) and 14.98 (3.40-66.08), respectively (chi-squared test for trend P < 0.001). Fetus papyraceous was significantly more likely among pregnancies exposed to a high concentration of methylene blue (P < 0.001) than among unexposed pregnancies. These results support the hypothesis that methylene blue dye use during mid-trimester amniocentesis in twin pregnancy increases the risk of fetal death.

Amniocentesis↗

PubMed1991

The use of 16.16-dimethyl-PGE1-delta-methyl ester (Cervagem) vaginal pessaries for cervical dilatation prior to evacuation for second trimester termination.

The results of a study of 101 consecutive second trimester terminations by Dilatation and Evacuation (D & E) under ultrasound control is presented. All had a Cervagem pessary inserted into the vagina prior to the procedure. The PGE1 analogue was assessed as 'effective' in 97% of patients. Concomitant ultrasound resulted in no patient leaving the operating table with retained products. The high efficacy of the single pessary associated with a low incidence of side-effects makes this combination the method of choice for nearly all second trimester terminations.

Abortifacient Agents, Nonsteroidal↗

PubMed1991

Completed follow-up of 1,000 consecutive transcervical chorionic villus samplings performed by a single operator.

Completed follow-up data on 1,000 patients undergoing transcervical chorionic villus sampling (CVS) performed by a single operator at the Royal Hospital for Women is presented. Prior to the introduction of CVS, approximately 750 amniocenteses were performed annually in this unit. Over the past 5 years the total number of patients having CVS or amniocentesis has increased by 1/3 and almost 1/2 of procedures are now done by CVS. We have persisted with the transcervical route believing that once the learning curve is past, this route compares favourably with the transabdominal method in loss rate and perinatal outcome. We feel the transcervical approach is better tolerated by our patients and that less procedural difficulties are encountered. With increasing operator experience the total fetal loss rate to 20 weeks' gestation in our series declined to 2.1% and late complications were no more frequent than expected. In 98.4% of patients, sufficient villi were obtained for analysis. Culture failure was extremely uncommon, occurring only twice in our series. In 1.5% of patients, a follow-up amniocentesis was required, which compares favourably with other published series. It appears that many units abandoned the transcervical route before loss rates were stabilized. In units where transcervical CVS is still performed the transabdominal route is also utilized. The reverse is not true. The authors feel that both procedures have a role in modern antenatal diagnosis.

Abortion, Induced↗

PubMed1986

Chorionic villus sampling. Clinical experience in 50 diagnostic cases.

The results of 50 diagnostic chorionic villus samplings (CVS) are presented. In all but 2, the fetus was at risk of a chromosomal abnormality. Sampling was successful in 48 cases. One patient aborted 4 days after the procedure. Two patients had missed abortions diagnosed on ultrasound 44 and 56 days after CVS. Seven patients elected to have their pregnancies terminated. All samplings were undertaken with a specially designed cannula using realtime ultrasound guidance between 9 and 11 weeks of amenorrhoea. Endocervical swabs and blood for maternal serum alpha fetoprotein estimations before and after the procedure were routinely taken. All patients were notified of the results in 8 days or less except in 3 where long-term cultures were necessary. Six patients have delivered and 34 pregnancies are continuing satisfactorily.

Abortion, Missed↗

PubMed1986

Chorionic villus sampling: cytogenetic experience in preliminary investigations and in 50 diagnostic cases.

The results of preliminary cytogenetic investigations of chorionic villus sampling (CVS) and its diagnostic application in 50 cases are reported. Preliminary investigations included the effect of short delays between biopsy and processing, levels of mitotic activity related to variations in processing, the incidence of tetraploidy, correlation of the karyotype of the chorionic villi with that of the fetus, and the results of banding studies. A protocol was then designed for application to diagnostic CVS. The 50 diagnostic cases included 4 with male karyotypes which were terminated due to a family history of an X-linked disorder, 1 trisomy 21, 1 trisomy 18, the finding of 1 aberrant cell out of 50 in an otherwise normal analysis, a 45, XY, t (13;21) karyotype, 2 fragile X negative karyotypes and in one case the presence of mosaicism was detected in chorionic villi and subsequently not confirmed at amniocentesis. The karyotype on the chorionic villi was 46XY/47XY +3.

Adult↗

PubMed1983

Trophoblast sampling by blind transcervical aspiration.

Blind transcervical aspiration for trophoblast was carried out on 137 patients undergoing elective termination of early pregnancies. Trophoblast was obtained from 45 patients (33%) usually at the first attempt. Collection was not necessarily more successful between 8 and 11 weeks of gestation. In only 13 patients (9%) was trophoblast collected without contamination by maternal tissue, or blood. Perforation of the amniotic sac in one patient (1%), bleeding either observed, or detected histologically (34%) and introduction of infection (4%) constitutes a real threat to fetal survival. Maternal serum alpha-fetoprotein estimation appears useful and may forewarn likelihood of fetal damage. Although transcervical aspiration should encounter ready acceptability as an out-patient procedure, modifications in the technique are essential before clinical application for detection of gene, or chromosome anomalies can be considered.

Biopsy, Needle↗