Assisted Reproductive Technology
Assisted Reproductive Technology, or ART, is a blanket term for a number of medical procedures used to address issues concerning reproductive functions of the human body. Not everyone can have children naturally. With ART, science steps in to provide these people with a choice they would not have had otherwise.
Ethically, this is a complicated matter, as any opportunity of artificially catering to instinct would be: fertility treatments have significantly increased the number of multiple pregnancies; ovarian stimulation can have serious side-effects; a child who was carried by a surrogate mother may wish to meet her against the wishes of the child’s legal parents. Factors like these require making difficult decisions.
Fertility
In the absence of any abnormalities, a heterosexual couple has about a 25% chance of conceiving per menstrual cycle. 60% of couples achieve this goal within 6 months, 80% achieve this within a year, and 90%—within 18 months.
The chances of success are largely dependent on timing. The ideal time to conceive is during the “fertile window”, which is a few days right around the time of ovulation (about two weeks before menstruation). An egg will survive in the fallopian tube for 12 to 24 hours—the aim is to have a sperm fertilize the egg within this time span. Sex is recommended at least three times a week for a couple trying for a baby.
If a year has gone by without results in the absence of any contraception and despite regular intercourse, it’s time to consider the possibility of fertility issues. It is at this point that examinations and tests are done to identify the possible causes. However, doctors operate on a case-by-case basis, and depending on the situation, it may be possible, even advisable, to arrange a consultation earlier.
Both men and women are affected by infertility, the numerous possible causes ranging from genetics to certain diseases to lifestyle choices. It’s important that both individuals consult their doctor together in order to size up the situation as a whole, discussing any habits or circumstances that might inhibit conception, as well as medical history and fertility assessment procedures.
For men, fertility assessment usually means semen analysis (assessing sperm count, motility, morphology, as well as the sample’s volume and pH), and can include biochemical semen analysis (that evaluates the function of accessory sexual organs).
For women, fertility assessment can include blood tests (measuring the levels of certain hormones), a hysterosalpingography (an X-ray of the womb and fallopian tubes), or laparoscopy.
Both men and women may be tested for Chlamydia (an STI that affects fertility), given an ultrasound scan, a hormonal assay test, or karyotype test (to check for possible genetic factors).
In some cases, switching to a healthier lifestyle (quitting smoking/drinking, making dietary adjustments, regulating bodyweight) can sufficiently improve fertility. In others, the solution may be surgically removing fibroids or endometrial scarring that affect the shape of the uterus and make it more difficult to conceive, surgically removing a blockage in the vas deferens, or regulating hormones with hormone treatments.
ART is no walk in the park—it can be emotionally difficult, time-consuming and expensive. Prospective parents should weigh their options carefully before moving forward with any serious procedures.
Ovarian stimulation
Female hormones are secreted by the hypothalamus, pituitary gland, and the ovaries. The hypothalamus secretes GnRH (gonadotropin-releasing hormone), the pituitary gland secretes gonadotropins: luteinizing hormone (LH) and follicle-stimulating hormone (FSH), and the ovaries produce estrogen and progesterone. GnRH modulates the secretion of gonadotropins, which regulate the secretion of estrogen and progesterone, and estrogens inhibit the secretion of GnRH, LH and FSH. Ovarian stimulation can therefore act on all three levels.
There are two main types of ovarian stimulation:
- Ovarian stimulation on its own, appropriate in cases of ovulation disorders.
- Ovarian stimulation in the context of ART (artificial insemination or in vitro fertilization).
As part of treating infertility related to ovulation disorders, a doctor may prescribe an antiestrogen—clomiphene citrate. It binds to the estrogen receptors in the hypothalamus and pituitary gland, and prevents them from reducing the FSH and LH levels.
Antiestrogens have the advantage of being taken orally, and they don’t require the close monitoring that other treatments do. The risk of hyperstimulation is also lower. This is why they are recommended as first-choice therapy when faced with anovulation (no ovulation) or dysovulation (irregular ovulation)—when the ovaries secrete estrogen and the pituitary gland is able to function.
However, antiestrogens do have side effects, such as impaired vision, hot flashes, headaches and bleeding between periods. The risk of multiple pregnancy is also increased, as well as the rate of miscarriage and ectopic pregnancy.
In the case of ovulation induction before in vitro fertilization or artificial insemination, ovarian stimulation consists of two phases, the first of which aims at blocking the production of LH and FSH, and completely controlling the woman's cycle using GnRH agonists and GnRH antagonists in the form of injections.
If the treatment has yielded no results after a few cycles, more powerful drugs are used—essentially gonadotropins that will act directly on the ovaries to develop follicles. Women with anovulation of hypothalamic or pituitary origin are also treated this way.
These drugs are injected subcutaneously, and may be self-administered. Gonadotropins are more effective than clomiphene citrate, but the risk of ovarian hyperstimulation syndrome and multiple pregnancy is higher, requiring repeated ultrasounds and hormonal assays to accurately adjust doses for each individual case, and monitor follicle development.
When several follicles have developed, the prospective mother is given an injection of chorionic gonadotropins (hCG), a hormone that induces ovulation within 32 to 38 hours.
Gonadotropins can cause ovarian hyperstimulation syndrome, manifesting as swollen and painful ovaries, and, in severe cases, as weight gain, abdominal pain, vomiting and shortness of breath.
Gonadotropins can also increase the chance of multifetal pregnancy. Although the majority of multiple births are carried out successfully, multiple pregnancies are still considered high-risk. Multifetal reduction surgery improves the chances of giving birth to a healthy child by removing one or more surplus fetuses. Although it may be necessary in the face of complications, this can be an emotionally heavy decision to make.
Intrauterine insemination (IUI)
Intrauterine insemination, or artificial insemination, is a fairly straightforward treatment in three steps:
- A semen sample is rid of unnecessary mucus and non-motile sperm, resulting in a small, concentrated dose of healthy sperm.
- The prospective mother monitors for ovulation with a predictor kit or is monitored by a doctor. This is either in sync with her natural cycle, or in combination with fertility medications that stimulate egg production.
- A day or two after ovulation, the sperm is inserted into the mother’s uterus using a catheter. After lying on her back for a moment, she is free to go.
IUI is often used in cases of unexplained infertility, and in cases where the sperm has difficulty reaching an egg, e.g. due to the sperm being impaired; the way to the egg being impeded by mucus or scarring; the absence of an egg.
Couples unable to provide viable sperm themselves—such as infertile couples, lesbian couples, and single women that wish to become single mothers—can use donor sperm for the procedure. All donor sperm is screened for infections and inherited diseases. Couples unable to carry a baby to term might utilise the services of a surrogate mother, also thanks to the procedure.
IUI can also aid in cases of semen allergy, usually characterised by redness, swelling, and a burning sensation upon contact with semen. This rare condition can affect men and women alike. Use of condoms can prevent a reaction, and there’s also the lengthier, but more permanent option of desentization. IUI is a good option for women unable or unwilling to tolerate their allergies, as the proteins causing the reaction are removed prior to the procedure.
Intrauterine insemination is relatively safe. There is a small risk of infection, and there can be some spotting after the procedure, but the vaginal bleeding is mostly insignificant. When coordinated with ovarian stimulation, there is an increased risk of multiple pregnancy.
IUI is usually not a viable option in cases of mild endometriosis, a low sperm count or low-quality sperm, and unexplained infertility—in these cases, the procedure is unlikely to be effective.
In vitro fertilization (IVF)
In vitro fertilization is fertilizing eggs in laboratory conditions—in vitro, which literally means “in a test tube”. This method is usually proposed to couples who cannot benefit from simpler ART methods, or have tried them and failed. IVF also makes gestational surrogacy possible: the egg of the prospective mother is fertilized by the sperm of the prospective father, and the embryo is carried to term by the surrogate mother.
- Step one of IVF is Control Ovarian Hyperstimulation (COF). It’s a process that starts off with suppressing the prospective mother’s natural menstrual cycle to prevent premature ovulation. She is given daily injections of gonadotropins, which facilitate a greater production of eggs. The progress of egg development is monitored closely before instigating ovulation with an injection of HCG.
- Step two: after 34-36 hours after the HCG injection, the mature eggs are collected, scanned, and placed in an incubator.
- In step three, the sperm are transferred to a dish containing the eggs, allowing the eggs to be fertilized and become zygotes. A zygote that is developing well may be selected to grow into a blastocyst, which has a higher chance of implantation.
- In step four, one or two of the highest quality embryos are selected and placed in the uterus with a soft catheter.
If all goes well, an embryo will implant itself, resulting in a healthy pregnancy. The success of in vitro fertilization treatment depends on factors such as the age and lifestyle of the prospective parents, the cause of infertility, the number of embryos transferred during the stage of fertilization, and the number of cycles performed.
There are risks to consider. A multifetal pregnancy may occur if more than one embryo is transferred to the uterus. A pregnancy with multiple fetuses carries a higher risk of early labor and low birth weight.
Use of injectable fertility drugs (such as HCG) to stimulate ovulation can cause ovarian hyperstimulation syndrome, which causes the ovaries to become swollen and painful.
The rate of miscarriage for women who conceive with the help of IVF is about 15% to 25%, which is close to that of women who conceive naturally.
There can be complications during the egg-retrieval procedure. Use of an aspirating needle to collect eggs can cause bleeding, infection or damage to the bowel, bladder or a blood vessel. Risks are also associated with sedation and general anesthesia.
2% to 5% of women who use IVF develop an ectopic pregnancy. This occurs when the fertilized egg implants outside the uterus, usually in a fallopian tube. In these cases, the pregnancy can’t continue normally, and it requires emergency treatment.
The risk of birth defects increases proportionally with the age of the mother, no matter how the child is conceived. This is why IVF is not recommended for a woman over the age of 40. Similar age limits often apply to sperm and egg donors.
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