Natural cycle in vitro fertilization (IVF), which requires no fertility drugs to produce multiple eggs, may represent the “greening” of the fertility field. This approach assumes that pregnancy for the “fertility challenged” can occur using just one embryo, and it is closer to what occurs in nature. But as in traditional IVF, the woman’s egg must be harvested, fertilized and transferred to her uterus. Yet for women who want to avoid the emotional roller coasters and potentially unknown long-term effects of fertility drugs, natural cycle IVF may be an ideal option.

What Is Natural Cycle IVF?

With natural cycle IVF, the menstrual cycle is carefully tracked. Then, during an outpatient procedure, the fertility doctor retrieves one egg through a small abdominal incision, which is typically peformed with a transvaginal ultrasound. The egg is then fertilized with the male partner's sperm or donor sperm in the IVF lab and incubated for several days before the embryo transfer. If successful, the embryo will develop into a healthy baby.

In contrast to regular IVF where women must take hormones to prompt the release of numerous eggs and to ripen them, in most natural IVF cycles only the hormone hCG is used to trigger release of the eggs. This not only saves money in fertility drugs and workup procedures, but it also quells worry about the long-term effects of fertility drugs.

History of Natural Cycle IVF

Natural cycle IVF dates back to the first successful human conceived using IVF. Louise Joy Brown, born July 25, 1978, in Manchester, England, resulted from natural cycle IVF. Her mother, who tried to conceive for nine years, used no artificial hormones to produce the single mature egg. The egg was retrieved during a normal cycle, combined with her father’s sperm, fertilized in a lab and transferred to the mother's uterus, where it implanted.

Today's Use of Natural Cycle IVF

In the 1980s, fertility doctors turned away from the natural IVF method when they discovered that hormone injections could control the timing of ovulation and could also stimulate ovaries to release numerous eggs per cycle. Fertility doctors believed that the more eggs a woman produced each month, the more that could be fertilized, thus increasing her chances of pregnancy.

As ovarian stimulation and retrieval techniques have improved over the last 10 to 15 years, fertility clinics have begun transferring fewer embryos per cycle to reduce chances of multiple births, and there is an increase in the number of single embryo transfers. The success with natural cycle IVF is highly dependent on the age of the women.