The term “test tube baby” is a non-medical, historical phrase that describes a child conceived through the process of In Vitro Fertilization (IVF). This colloquialism originated because the sperm and egg are combined in a laboratory dish, not in a woman’s body, before pregnancy is initiated. The proper medical term is In Vitro Fertilization, which literally means “fertilization in glass.” The birth of the first baby conceived this way, Louise Joy Brown, occurred in July 1978.
Understanding In Vitro Fertilization
In Vitro Fertilization is a multi-step procedure that begins with controlled ovarian hyperstimulation, where hormone medications encourage the ovaries to produce multiple mature eggs in a single cycle. This process is monitored using blood tests and transvaginal ultrasounds to track the growth of follicles containing the eggs. The goal is to maximize the number of viable eggs for retrieval.
Once the follicles reach a precise size, a final injection, often called a “trigger shot,” is given to induce the final maturation of the eggs. Approximately 36 hours later, the egg retrieval procedure is performed under light sedation. A thin, ultrasound-guided needle is passed through the vaginal wall to aspirate the fluid and eggs from each follicle.
In the laboratory, retrieved eggs are combined with sperm in a culture dish (traditional insemination). For severe male infertility, a single sperm can be injected directly into each egg using Intracytoplasmic Sperm Injection (ICSI). The resulting fertilized eggs, now embryos, are cultured for three to five days to assess their development and quality.
The final step is the embryo transfer, where the selected embryo is placed into the woman’s uterus using an ultrasound-guided catheter. The embryo is typically transferred at the blastocyst stage (day five or six). Any high-quality embryos not transferred can be cryopreserved for future use.
Candidates for IVF Treatment
IVF was originally developed to help women with blocked or damaged fallopian tubes, as the procedure completely bypasses these structures. Tubal factor infertility remains a common indication for treatment. The procedure is now used to address a wide range of fertility challenges affecting both men and women.
Male factor infertility, such as low sperm count or poor sperm motility, is frequently addressed with IVF, often utilizing the ICSI technique. Women with conditions like endometriosis or Polycystic Ovary Syndrome (PCOS) are also strong candidates. IVF can help these women overcome hormonal imbalances and physical barriers to conception.
The treatment is also a viable option for couples diagnosed with unexplained infertility, where standard diagnostic tests fail to identify a specific cause. Additionally, it is used when other less invasive treatments, such as intrauterine insemination (IUI), have been unsuccessful. Advanced maternal age is another significant factor, as IVF allows for the potential screening of embryos for chromosomal abnormalities before transfer.
Success Rates and Potential Health Concerns
IVF success rates vary significantly based on the woman’s age, the cause of infertility, and clinic protocols. Generally, women under the age of 35 have the highest live birth rates per cycle, often exceeding 40% to 50%. This rate reflects the higher quality and quantity of eggs typically found in younger women.
The chance of success decreases noticeably as a woman ages, primarily due to the decline in egg quality and a corresponding increase in chromosomal abnormalities in the embryos. For women over 40, the live birth rate per cycle using their own eggs may fall below 10%. Cumulative success rates, achieved over multiple cycles, are typically much higher than the rate for a single attempt.
One of the most common risks is Ovarian Hyperstimulation Syndrome (OHSS), where the ovaries become swollen and painful due to stimulating medications. Another concern is the increased possibility of multiple births, which carry higher risks for the mother and the babies, including premature birth and low birth weight. Current medical practice focuses on single embryo transfer (SET) to minimize this risk.