Reproductive Technology

Surrogacy, in which pregnancy occurs in another woman, can supply a couple with an alternative if the woman partner cannot carry the baby to term in her own uterus. In some cases, if the woman cannot supply the egg, sperm from the male partner can be used to inseminate the surrogate mother, who carries the baby to term. Alternatively, if the female partner can produce her own egg, sperm from the male partner can be used to fertilize the egg, and the resulting pre-embryo can be transferred to the uterus of the surrogate mother to grow and develop. Legal controversies resulting from these arrangements have become common in the last few years, so the arrangements should be carefully reviewed by all parties, along with experts in the field, before any final decisions are made.

Frozen sperm and embryos effectively retain their viability for many years. The use of frozen human blastocysts is associated with a 10 percent successful pregnancy rate. Oocyte freezing is much less successful, possibly because oocytes may be genetically damaged or killed in the freezing and thawing. Embryos produced from such cryopreserved eggs have a high incidence of aneuploidy, and they are slow to cleave and develop even if they appear to be genetically undamaged. Various research groups are trying to solve this problem.