Infertility treatments involving fertility drugs and management of eggs, sperm, and embryos outside of the human body are called Assisted Reproductive Technologies (ART). In Vitro Fertilization (IVF) is the most common type of ART. IVF has a relatively short history. It started in 1978, with the birth of Louise Brown, the first baby born via IVF. In 2011, more than 61,610 babies were born in US using ART – mostly with IVF.
There are four basic steps involved in IVF
- Ovulation induction – fertility medications are prescribed to control the timing of the egg ripening and to increase the chance of collecting multiple eggs. Multiple eggs are desired because some eggs will not develop or fertilize after retrieval.
- Eggs and sperms are collected
- Eggs and sperms are combined in the laboratory. An appropriate environment for fertilization and early embryo growth is provided
- Embryos are transferred to the uterus
Other ART techniques used are:
- Intracytoplasmic sperm injection (ICSI): One sperm is placed inside an egg with a microscopic needle. Once fertilization occurs, the resulting embryo is placed in the uterus to implant.
- Gamete intrafallopian transfer (GIFT): Eggs are combined with sperms in the laboratory and then surgically injected into the fallopian tubes. Fertilization happens inside the body and the embryo implants naturally.
- Zygote intrafallopian transfer (ZIFT): Eggs are mixed with sperms in the laboratory, after fertilization occurs the embryo is surgically placed in the fallopian tubes and the embryo implants naturally.
5 Possible Health Risks Associated with IVF
Infertility treatments can help women have the baby they have always longed for, but it can be physically, emotionally and financially draining. Reaching out to close friends and family to help cope with the ups and down of infertility treatment can alleviate the associated emotional distress. And, as with most medical procedures, there are potential risks. There are risks associated with the use of fertility drugs which are used to stimulate egg growth and the risk of multiple births as multiple embryos are usually transferred into the uterus.
1. Correct Fertility Drug Dosage
Gonadotropins are injectable fertility medications that contain follicle-stimulating hormone (FSH) alone or combined with luteinizing hormone (LH). During a regularly occurring menstrual cycle, both FSH and LH are produced by the pituitary gland in the brain and stimulate the ovaries to make a single egg each month. When FSH (with or without LH) is given as an injection, it works directly on the ovaries to make multiple follicles, cysts containing eggs. Monitoring the ovarian response is necessary and a combination of blood estrogen measurement and ultrasound is usually used.
Other fertility medications, such as clomiphene citrate, an oral medication, induce ovulation by blocking estrogen receptors. This tricks the body into believing that estrogen levels are low, which stimulates the production of more follicle stimulating hormone (FSH), inducing ovulation. Determining the right dose of medication to stimulate ovulation can take several cycles and ovarian monitoring while taking clomiphene citrate may include ultrasounds and measurement of blood estrogen levels.
2. Risk of Hyper Stimulation of Ovaries
The next step is triggering the eggs to go through the last stage of maturation to be retrieved. This maturation is triggered by injecting human chorionic gonadotropin (hCG), which has a half life of 8 days and can stay in a woman’s body for weeks, sometimes causing the ovaries to become overactive, swollen and painful. This condition, called Ovarian Hyper Stimulation Syndrome (OHSS), affects around five per cent of women who undergo IVF. In women who suffer from polycystic ovary syndrome, where they have more eggs than normal, the risk is even greater.
Approximately, 1-2% of women develop Severe Hyperstimulation Syndrome, a potentially dangerous medical condition requiring hospitalisation. This condition is likely to occur in women who develop in excess of 20 eggs, but has been known to occur with fewer eggs.
3. Risk of Ovarian Twisting and Ectopic Pregnancy
Ovarian twisting, a condition associated with the maturation of multiple follicles, occurs in about 2% of gonadotropin cycles. The stimulated ovary can twist on itself as it is heavier from more follicles and cut off the blood supply with surgery being required to untwist the ovary.
About 2-5% of women who use IVF have an ectopic pregnancy — when the fertilized egg implants outside the uterus, usually in a fallopian tube. The fertilized egg can’t survive outside the uterus, and the pregnancy is not viable and can be dangerous for the mother leading to internal haemorrhage.
4. Risk of Cancer
There have been concerns that the use of fertility drugs is associated with an increased risk of cancer. Scientific literature provides contradictory information on the association of ovulation induction treatment and cancer incidence but we have to remember, that for the analysis to be meaningful, only studies collecting data on a large number of women with adequate information on their treatment modality, hormone status and exposure throughout their reproductive years, with prolonged follow-up, can confirm or refute the findings.
Some studies have reported an increase of ovarian cancer risk after use of fertility drugs while other studies have not observed any increase in risk. A publication, ‘Risk of borderline and invasive ovarian tumours after ovarian stimulation for in vitro fertilization in a large Dutch cohort’ reports on 16,343 women who received at least one IVF cycle and ovarian stimulation, with a follow-up of 15 years. The researchers found that increase in risk was mostly due to borderline ovarian tumours which exhibit less aggressive behaviour than invasive ovarian cancer and are more treatable. These results are based on IVF treatment protocols used until 1995, prior to the adoption of currently applied milder stimulation regimens.
Medical records of 5,788 women who attended infertility centers between 1964 and 1984 were followed till the women reached the age of 50 years, for incidence of breast cancer. The results, ‘Infertility, ovulation induction treatments and the incidence of breast cancer – a historical perspective cohort of Israeli women’ had found increased breast cancer risk with the use of clomiphene citrate but not with other infertility drugs. However, the authors noted – though the follow-up period was long, the mean-age at end of follow-up (49.9 years) was not the peak-age for breast cancer incidence.
5. Risk of Multiple Pregnancy
The chance of a multiple pregnancy is higher in all assisted reproductive procedures, increasing the risk of multiple births if more than one embryo implants in the uterus. A recent study found a sharp increase in the number of multiple births between 1984 and 2007 in fourteen countries across Europe – most of which were ascribed by researchers to ART.
A pregnancy with multiple foetuses carries a higher risk of early labour and low birth weight than pregnancy with a single foetus. Premature birth is associated with multiple health risks for babies.
To reduce multiple pregnancy rate after IVF or ART, elective single embryo transfer (eSET) has been introduced. For eSET to be successful, the availability of an embryo with a high potential for implantation is important. Preimplantation Genetic Diagnosis (PGD) and Preimplantation Genetic Screening (PGS) are genetic tests to help identify embryos suitable for transfer to the uterus. Embryos are screened for abnormal number of chromosomes and only those with the correct number of chromosomes are transferred. A PGD for chromosomal abnormalities has been shown to improve success rate for women who are 38 years or older and the technique reduces the risk of congenital genetic diseases. Genetic screening of prospective parents for mutations linked to genetic diseases, i.e. carrier status analysis, in conjunction with PDG can ensure selection of healthy embryos improving the outcome of fertility treatments.
The Future of Assisted Reproductive Technology
The use of Assisted Reproductive Technology has increased dramatically and more and more women are turning to IVF to help them conceive. Retrospective and prospective follow-up studies on the long term health effects on women undergoing treatment and the potential associated health risks to children conceived through IVF are essential.
If you would like to learn more about in vitro fertilization, continue reading this related blog post: “Fertility Problems in Women: When to Ask for Treatment”.