Soft forceps.

OBJECTIVE: The risk of maternal and fetal trauma and, chiefly, the fear of law suits, have contributed to a significant decline in rates of forceps-assisted deliveries and an increase in rates of cesarean sections, especially in the United States. Our experience with gas-sterilized forceps blades covered with a soft rubber coating--the "soft" forceps--is described. METHOD: Ninety-six women who required a forceps-assisted delivery for standard indications were randomly allocated to 2 groups. There were 51 women in the regular forceps group and 45 women in the soft forceps group. Low forceps delivery with a Simpson instrument was used in all cases. The groups were compared for fetal injury. RESULTS: The rates of severe facial abrasion and minimal marking were 4.1% and 61%, respectively, in the regular forceps group and 1.9% and 34% in the soft forceps group. CONCLUSION: The soft forceps may reduce the rates of neonatal facial abrasion and skin bruises. The forceps should be further perfected, as well as vacuum extractors; they should both continue to be part of the obstetrician's armamentarium.

Tetraploidy and aneuploidy after observation of diploid fertilization in vitro.

A case is described in which a tetraploid and aneuploid conceptus resulted from dipronuclear embryos from in vitro fertilization. This finding strongly suggests that, after a meiotic error in either the egg or sperm, polyploidy has occurred as the result of a postfertilization mitotic error.

Cell-free human amniotic fluid as culture medium for mouse and human embryos.

Differences between murine and human preimplantation embryonic growth in cell-free human amniotic fluid and medium F-10 supplemented with human fetal cord serum were assessed. Two-cell mouse embryos cultured in human amniotic fluid developed more consistently to the expanded blastocyst stage than those cultured in F-10. No significant difference in human preimplantation embryo cleavage was observed between the two culture conditions. However, amniotic fluid was significantly worse than F-10 + human serum in its ability to maintain embryos that could establish pregnancy after transfer.

Embryonic development and pregnancy from fresh and cryopreserved sibling pronucleate human zygotes.

The number of pronucleate (PN) zygotes that cleave, rates of cell division, and pregnancy rates were compared from fresh and frozen sibling PN zygotes. Of 57 patients with randomly selected zygotes frozen at the PN stage, 26 have had 82 PN zygotes thawed with 76 (92.7%) morphologically intact immediately post-thaw. There was no significant difference (P greater than 0.05) in the proportion of fresh (110/123 [89.4%]) and frozen-thawed intact (62/76 [81.6%]) sibling PN zygotes that had cleaved by transfer. The number of fresh versus frozen-thawed sibling PN zygotes that developed into 2-, 3-, 4-, 5-, 6-, 7-, and 8-cell embryos after 24 hours in culture were not significantly different. The numbers of pregnancies per patient cycle for fresh and frozen-thawed sibling PN zygotes were 12/60 (20.0%) and 5/27 (18.5%), respectively (P greater than 0.05). The current cumulative pregnancy rate per retrieval in all cycles with frozen zygotes is 28.3%, considerably higher than observed in single transfers of embryos without cryopreservation (19.8%); predicted cumulative pregnancy rate after eventual transfer of all frozen zygotes is 37.9%. It is concluded that embryo survival and pregnancy rates of cryopreserved PN zygotes are very similar to those from their fresh sibling counterparts and cryopreservation substantially enhances in vitro fertilization pregnancy attainment.