In vitro fertilization (IVF) is a medical procedure in which eggs and sperm are fertilized in the laboratory and the resulting fertilized eggs or embryos are returned to the mother to establish a pregnancy. Physicians use variations on this traditional IVF model depending on the specific medical or social needs of the couple wishing to become parents.
Traditional IVF
The simplest IVF procedure usually ocurrs between a man and a woman who are married or mutually monogamous partners. IVF typically requires a period of ovarian stimulation first so that the woman can produce multiple mature eggs at one time that physicians can recover during an outpatient surgical procedure called transvaginal ultrasound guided oocyte retrieval. In this procedure, the physician uses a vaginal ultrasound probe to visualize the mature follicles on the surface of the ovary. Next, she attaches a sterile needle to the ultrasound probe and uses it to suction eggs and fluid from each mature follicle. The man produces a semen sample by masturbation and both sperm and egg are processed in the fertility lab to achieve fertilization. One early variation of basic IVF returned the newly fertilized eggs to the Fallopian tubes in a procedure called zygote intra Fallopian tube transfer (ZIFT). According to the American Fertility Association, most fertility labs today keep the fertilized eggs in the lab for 3 to 5 more days to allow the fertilized eggs to develop into more mature embryos which they transfer to the uterus, not the Fallopian tubes.
IVF with donor gametes
Another IVF variation uses either donor eggs or donor sperm for IVF. Sometimes, this procedure uses both donor eggs and donor sperm. The Food and Drug Administration (FDA) regulates the process of screening potential egg and sperm donors, requiring risk factor screening questionnaires, physical exams and blood tests to determine whether a donor is eligible to donate. Most donors who contribute eggs or sperm for IVF remain anonymous, but some couples may ask known donors, usually a relative or close friend to donate gametes for their IVF case. If they use donor eggs, the female donor will need to undergo ovarian stimulation and egg retrieval, but the resulting embryos are returned not to the uterus of the egg donor but to the intended mother. Donor sperm is collected by masturbation and usually frozen and stored for six months until the donor passes a secondary screening allowing the sample to be released from quarantine. The FDA allows couples to waive the six month quarantine period for a known donor.
IVF with gestational surrogates
Another twist on traditional IVF includes using a gestational surrogate to carry the embryos of the intended parents. A gestational surrogate, unlike a true surrogate, provides her uterus to carry the pregnancy but has no genetic link to the baby, because the gestational surrogate does not contribute her egg. IVF makes this arrangement possible because the couple's egg and sperm are fertilized in the laboratory, with the resulting embryos returned to the gestational surrogate to create a pregnancy. Nine months later, the intended couple receives the newborn to raise. In some states, the intended couple must formally adopt their genetic child when born to a gestational surrogate. Couples find surrogates through commercial matching services or sometimes ask a friend or relative. In either case, legal agreements help to clarify the expectations of everyone involved. The FDA requires screening of the couple who use the services of a gestational surrogate.
