Pieter Hummel

'Identical' twins with discordant karyotypes

A chromosomal abnormality in one of the fetuses of a monozygotic twin pregnancy is a rare phenomenon. In the prenatal unit of our cytogenetics laboratory we have recently come across two such heterokaryotypic twin pregnancies. In both cases ultrasound abnormalities were detected in one fetus of each twin pair. Chromosomal analysis showed that one twin pregnancy was discordant for trisomy 21 and the other for 45,X. Ultrasonographic examination suggested a monochorionic twin pregnancy in each case and DNA studies confirmed that both sets of twins were monozygotic. Both pregnancies were terminated. Biopsies taken from different sites of the placentas showed chromosomal mosaicism in both cases. There was no clear correlation between the karyotype found close to the site of the umbilical cord insertion in the placenta and the karyotype of the fetus. Sampling of amniotic fluid from both sacs is recommended in diamniotic twin pregnancies if one (or both) of the fetuses has ultrasound abnormalities, even if the twins are apparently monochorionic. Copyright

Loop electrosurgical excision procedure of the cervix and time of delivery in subsequent pregnancy

Objective: To study the effect of the loop electrosurgical excision procedure (LEEP) on gestational age at delivery in the subsequent pregnancy. Method: Identification of women with LEEP. Chart analysis and inquiry into gestational age at the subsequent delivery. Exclusion of first trimester abortions, multiple gestations, cold knife conizations and women over 40 years during LEEP. For comparison, 40 weeks was used as the mean date of delivery in a normal population. Wilcoxon signed rank test was used and P<0.05 was considered significant. Result: Fifty‐six women delivered after LEEP. Seven delivered preterm of whom three were induced and one had a history of preterm delivery. Deliveries prior to 32 weeks of gestation did not occur. Mean gestational age at delivery was 39 2/7 weeks (95%CI: 38 5/7–39 6/7) which is significantly earlier (P=0.03) than the hypothetical 40 weeks. Conclusion: After LEEP, deliveries prior to 32 weeks did not occur. Gestational age at delivery was only 5 days earlier than expected. LEEP cannot be considered a risk for early preterm delivery.