What is in vitro fertilization, and what are its benefits?

In vitro, meaning literally 'in glass', fertilization is often performed as an alternative to tubal surgery or other potentially excessive means in the pursuit of pregnancy. It is an option for couples who have reproductive complications ranging through tubal blockage, uterine or tubal scarring, or infertility resulting from endometriosis. It also allows one to circumvent tubal ligation and vasectomy without invasive surgery and to produce a fertile embryo despite dysfunctional sperm or a low sperm count on the part of the male.

In vitro fertilization (IVF) consists of the combination of a sperm and egg in a controlled medical environment for the purpose of re-implantation into the uterus of the female, from which point it develops naturally in the womb as would an embryo conceived traditionally. A single round of IVF usually involves the implantation of two to four embryos, as the rate of failure per embryo is significant--generally, the rate of success after one cycle is about 25%, which increases with each progressive cycle attempted. Because multiple embryos are implanted into the uterus, there is the possibility with most methods of IVF of multiple births. Of 82% reported pregnancies producing live births (18% allotted to miscarriages), 63% are single, 32% twins, and about 5% are triplets or more. Multiple implantation is done so as to assure greater odds of success, but as it can result in extra births, IVF must be considered as a medical option with this in account.

Defects in male sperm can be an issue in the success of IVF as much as in traditional conception. If the sperm is genetically unsound, or is incapable of fertilization for whatever reason, even once combined with the egg in vitro, successful pregnancy will not result. IVF can be considered as an alternative for those with defective sperm, but its main advantage over traditional conception is in the realm of sperm motility. The sperm do not have to travel the length of the vagina and uterus with IVF, which gives them a distinctive advantage in the fertilization process.

IVF is also used in cases where men or women exhibit an immune response to sperm cells, a moderately common disorder that tends to result in the death of the cells before they reach their goal, and which is recognizable at times in women by a mild vaginal itch which appears only several minutes after ejaculation during intercourse. As the process singles out individual sperm cells to combine them with individual eggs, there is no chance for either individual's immune system to render them inoperative, thereby bypassing this complication.

Typically, IVF costs about $12,500 a cycle. As the first cycle produces odds of about 25% effectiveness, it may take multiple cycles to produce a viable embryo. Alternatives to IVF depend upon the condition causing the infertility, but may include for women tubal surgery or tubal reversal, or vasovasostomy, in males who've had a vasectomy.

A wide variety of studies have indicated no negative effects to be found, on average, in children conceived using IVF, as compared to those conceived traditionally. Select studies have professed that a slight additional risk of genetic defect may exist, but additional research is forthcoming on the subject.