Ultrasound

Virtually all ultrasound scanning in assisted conception is performed transvaginally. The initial scan assesses several areas.

• Ovarian morphology: if there are underlying polycystic ovaries, they may be hyperresponsive to stimulation with gonadotrophins.
  
• Presence of ovarian cysts: if present, suitable treatment should be arranged.
  
• Many centres now also measure the antral follicle count (AFC) as this is also used in the dose calculation of FSH for the stimulation phase of IVF.
  
• The ovaries are assessed for accessibility, not just for the monitoring itself but also if transvaginal oocyte retrieval (TVOR) is planned in order to ensure that this can be performed without undue difficulty. Sometimes in patients who have abdominal adhesions due to iatrogenic causes, previous pelvic inflammatory disease or endometriosis, then gentle abdominal pressure can be applied during the screening ultrasound to ensure that the ovary can be moved down to a more accessible position for egg collection.
  
• The uterus is also assessed for the presence of abnormalities such as uterine fibroids to ensure the endometrium appears normal and there are no other abnormalities.
  
• The rest of the pelvis is also screened in a systematic fashion to exclude other pathology.

Uterine cavity and tubal patency

Both the uterine cavity and the fallopian tubes should be examined prior to all forms of assisted conception. For techniques such as IUI, where either one or both fallopian tubes are required to be patent, it is obvious why both the cavity and the tubes should be checked. Less obviously, the fallopian tubes require inspection for techniques such as IVF, even though they are not required for the actual procedure. We know from grade A evidence [1] that the presence of hydrosalpinges can significantly reduce the implantation rate due to reflux of the hydrosalpingeal fluid into the uterine cavity. The integrity of the uterine cavity should be evaluated as various forms of pathology, including intrauterine adhesions, congenital abnormalities such as large septate uterus, submucous fibroids and intrauterine polyps, can all significantly reduce the implantation rate and hence the subsequent live‐birth rate from all forms of assisted conception. If a significant problem is noted in the uterine cavity, this would normally be corrected prior to the assisted conception cycles being performed. The uterine cavity and the fallopian tubes can be investigated using the following methods.

Uterine fibroids

Uterine fibroids are very commonly detected by transvaginal scanning of the infertile woman. It has always been difficult to ascertain the causality between these fibroids and the patient’s infertile status, but the presence of fibroids does not necessarily mean there is a direct causal link between fibroids and infertility. On the other hand, there are a number of reported case series where removal of fibroids resulted in subsequent improved conception rates of between 30 and 80% [3]. It was previously thought that fibroids only significantly reduced implantation rates if the uterine cavity was distorted. Two series examined the effect of fibroids in other locations on implantation in IVF cycles. In the first of these, Eldar‐Geva [4] showed that intramural fibroids significantly reduced implantation rates; this was then confirmed by Hart et al. [5]. Both of these studies confirmed the impact of fibroids that do not distort the uterine cavity but this appears to be only true for fibroids above 3 cm in size. Therefore, any patient who has fibroids larger than 3 cm, and in particular who has recurrent implantation failures, should be considered for myomectomy prior to further assisted conception. Although treatment of these fibroids does appear to have an impact on implantation rates, in a randomized trial Surrey et al. [3] failed to demonstrate improved live‐birth rates.

Hydrosalpinges

There have been several studies that have shown the adverse effect of hydrosalpinges on IVF outcome. Indeed, three randomized controlled trials were included in the Cochrane review [6] to see if salpingectomy would be useful for patients with hydrosalpinges prior to undergoing IVF. Surgical treatment of these hydrosalpinges versus non‐surgical treatment increased the odds of live birth plus ongoing pregnancy (odds ratio, OR 2.13, 95% CI 1.24–3.65) and of pregnancy (OR 1.75, 95% CI 1.07–2.86). It has now been shown that removal of these diseased tubes by salpingectomy prior to IVF leads to the implantation rates that would be expected in patients unaffected by hydrosalpinges. Whether these hydrosalpinges should be removed or blocked in the proximal portion (by clipping or coagulation) will depend on several factors such as degree of damage and whether the patient has pain associated with the hydrosalpinges. Salpingectomy used to be the routine recommendation but more units are now coagulating the proximal portion because of the worry that salpingectomy may compromise ovarian vasculature and reduce subsequent response to stimulation [7 6]. Most practitioners would individualize the treatment of hydrosalpinges and take all other variable parameters into consideration, ranging from any male factor present through to degree of tubal disease, as well as the known ovarian function of the patient prior to removing them.

Polycystic ovaries

Polycystic ovaries as seen by ultrasound are an extremely common finding in women of childbearing age and can occur in about 30% of patients. Patients with polycystic ovaries can be more difficult to stimulate with gonadotrophins for either IUI or IVF. Initially there can be a degree of resistance at lower doses but then a very narrow therapeutic window before the patient hyperstimulates, and this can quite often lead to cycle cancellation. In view of the severe complications resulting from OHSS, one should always start with a low dose and then increase in small increments until the appropriate therapeutic window is achieved. Some have advocated the use of laparoscopic ovarian drilling to try to improve this therapeutic window, as well as the pre‐cycle administration of insulin‐sensitizing agents such as metformin. There is now evidence that metformin does not improve the success rate but can improve the safety of the cycle.

Endometriotic cysts

Endometriosis is a common coexistent pathology in patients undergoing assisted conception. Although there is little evidence that the routine treatment of peritoneal endometriosis results in a significant improvement in assisted conception cycles, there can be benefit in treating large endometriomas (>44 cm) prior to IVF. It is thought this may benefit the cycle in several ways, including the ovarian response itself and overall number of eggs obtained (particularly in the ovary containing the endometrioma). The second concern with ovarian endometriomas is that these can be inadvertently punctured during TVOR and there is a significant increase in ovarian abscess formation if this occurs. Pre‐cycle drainage by needle aspiration can also be a cause of ovarian abscesses and this is generally not advised. If the size of the ovarian endometrioma is felt to be significant so that it may adversely affect cycle outcome or increase the chance of inadvertent needling, then it is better for the endometrioma to be surgically treated prior to initiation of the cycle. Prolonged downregulation with GnRH analogues can shrink the cysts and also improve the overall success rates.

Smoking

Patients should be advised that smoking significantly reduces the effectiveness of all forms of assisted conception and that they should therefore quit smoking.

Obesity

It is recommended that a patient should have a body mass index (BMI) of between 19 and 30. Outside this range success rates of assisted conception are reduced. If the BMI is above 30, not only are success rates lower but miscarriage rates higher and complications such as OHSS increased. It is therefore recommended that the female partner should be encouraged to lose weight.

Protocols

IUI can be performed in a natural cycle, with Clomid alone, with Clomid and then FSH injection, or purely with FSH. If any form of ovulation induction has been used, it is also quite common to use a single human chorionic gonadotrophin (hCG) injection approximately 36 hours prior to the insemination to ensure optimal timing with ovulation.

Monitoring

Although for unstimulated cycles it is possible just to perform urinary luteinizing hormone (LH) monitoring using home dipstick methods, this does not give the best success rates. If any form of ovulation induction has been used, then it is recommended that more accurate monitoring is performed. This is normally achieved by transvaginal ultrasound and has benefits of not only deciding the best time to give the dose of hCG and hence the timing of the insemination, but also ensuring that ovulation induction is having the desired effect, i.e. one (or at most two) developing follicle(s) over 18 mm. If there are more than two follicles, this can be detected by ultrasound, the cycle cancelled and the patient advised against having unprotected intercourse due to the increased risk of higher‐order multiple pregnancies.

The overall success rate, as with any subfertile couple, depends on multiple factors, most importantly female age and, with IUI, the quality of the sperm. Though IUI can be used for mild male factor problems, it is not recommended for anything more severe. Success rates of around 5% per cycle have been quoted for unstimulated IUI, increasing to 8–10% per cycle for stimulation with Clomid and 12–18% per cycle when FSH is used in the protocol. Although success rates of 35% have been quoted in literature, these tend to be highly selective series and not necessarily representative of a general case mix of patients across a wider age range [8].

Complications

The main complication of IUI is higher‐order multiple births and occurs when FSH has been used. Most centres would expect a twinning rate of 10–15% and a triplet rate of less than 1%. If the triplet rate is higher than 1%, and in particular if there are even higher numbers than this, then this is normally due to inadequate monitoring and inadequate numbers of cycles being cancelled when an over‐response of the ovaries has been seen.

Although ovarian hyperstimulation can occur, particularly in the protocols where FSH is used, this would normally be mild to moderate at most, and it is very unusual to get a case of severe hyperstimulation in IUI cycles. If this happens it tends to be when an inappropriate starting dose of FSH has been used and again when inadequate monitoring has been performed.

The patient should also be warned about the possibility of ectopic pregnancies, and most clinics would offer an early ultrasound scan in the patients who have had a positive pregnancy test at between 6 and 7 weeks’ gestation.

Advantages

IUI is a relatively simple technique that is cost‐effective and can be offered by both secondary and tertiary fertility centres. It is not as invasive as IVF and allows fertilization to occur within the fallopian tubes and therefore it is generally acceptable to most religious groups.

Disadvantages

The success rates are lower than those with IVF, and if the cycle fails less information is obtained than with an IVF cycle, particularly pertaining to possible egg or subsequent embryo quality. It also requires at least one healthy fallopian tube and reasonable sperm parameters. If monitoring is suboptimal, then there can be a significant increase in higher‐order multiple births, with the expected sequelae.

Indications

• Unexplained infertility.
  
• Mild male factor.
  
• Ejaculatory problems.
  
• Cervical problems.
  
• Ovulatory disorders.
  
• Mild endometriosis.
  
• To optimize the use of donor sperm.

Indications

• Severe tubal disease: tubal blockages.
  
• Severe endometriosis.
  
• Moderate male factor.
  
• Unexplained infertility.
  
• Unsuccessful IUI.

Protocols

Initially, simple forms of ovulation induction using Clomid and hMGs were used. Over the last 20 years protocols have been refined and these are now classified into three main categories:

1. natural cycle;
   
2. long protocol (agonist cycles);
   
3. short protocol (antagonist cycles).

Although there are other short protocols using agonists, these are now less used due to poorer success rates.

Monitoring

It is essential that adequate monitoring is performed during stimulation of the ovaries with exogenous gonadotrophins. Serial transvaginal ultrasound to assess follicular growth should be used. A decreasing number of units continue to use serial estradiol levels to add to the information obtained from the ultrasound. The use of serial estradiol can be useful in some patient groups, particularly if an under‐ or over‐response is anticipated. An under‐response can sometimes be anticipated in the older patient or the patient with previously raised FSH levels. An over‐response can sometimes be anticipated if there has been a previous over‐response or if the patient has polycystic ovarian morphology on her initial diagnostic ultrasound. There seems to be no value in routine estradiol monitoring.

Monitoring during the stimulatory phase allows the dose to be increased or decreased, if appropriate, as well as the timing of the hCG injection.

hCG injection

This is used to induce final maturation of the oocytes prior to oocyte retrieval. Generally, recombinant hCG 250 µg subcutaneously in a prefilled pen is used. If urinary hCG is used, then a dose of 10 000 IU is given, although in patients with an over‐response this can be decreased to 5000 IU. hCG should be given when either one or two lead follicles have reached 18 mm. The injection is normally given around midnight to allow for oocyte retrieval approximately 35 hours later prior to physiological ovulation occurring. If the hCG injection is incorrectly administered, then either very few or no eggs are obtained at the egg collection.

Agonist trigger

If the patient is at significant risk of OHSS then, rather than using an hCG trigger with a prolonged half‐life and subsequent prolonged stimulation of the corpora lutea, an agonist trigger can be used. This gives a more normal LH surge with a shorter half‐life. This has been shown to significantly reduce the rates of severe OHSS. If an agonist trigger is used, then the luteal phase support is often modified (see section on luteal phase support). Agonist triggers are also used in egg donor cycles where the risk of OHSS has to be lower and the embryos are nor replaced in the donor herself.

Oocyte retrieval

Originally, this was done laparoscopically but the advent of real‐time ultrasound has allowed a less invasive oocyte retrieval by ultrasound‐directed needling of the ovaries. Smaller and better‐quality ultrasound probes, particularly with the advent of transvaginal scanning, has allowed both the monitoring of the ovary during stimulation and the actual retrieval itself to be performed transvaginally. Virtually all oocyte retrievals are performed by this transvaginal ultrasound‐directed route. The laparoscopic route is still occasionally used if the ovaries are inaccessible transvaginally. This can occasionally occur in frozen pelvises or when the ovaries have been moved out of the pelvis prior to pelvic irradiation.

TVOR can be performed under general anaesthesia or, more commonly, local anaesthesia or some form of intravenous sedation. The procedure generally takes 20–30 min, depending on how many follicles are present. Either a single‐use disposable needle is used or a double‐channel needle that allows ‘flushing’ of the follicle if the egg is not obtained on simple aspiration. The needle is inserted under ultrasound control directly into the follicles of one ovary and the fluid aspirated and given directly to the embryologist. If the egg is not found after all the fluid has been aspirated, then the follicle is flushed and re‐aspirated to try to find the egg, as well as using gentle needle agitation (Fig. 52.1). After all the follicles have been exhausted from one ovary, the needle is then withdrawn and reinserted under ultrasound control into the other ovary and the process repeated. After the ultrasound probe is removed, the vaginal vault is checked for bleeding; although bleeding is usually not a problem, occasionally an absorbable suture has to be inserted under direct vision for a specific bleeding point. Most patients go home a few hours after the procedure has been completed.

Embryo transfer

Eggs are fertilized either by routine insemination with a concentration of approximately 100 000 normally motile sperm per millilitre or by ICSI (see later section). They are incubated in a commercially prepared culture medium under strict laboratory conditions. The temperature within the incubators is carefully controlled, as are the gas content, humidity and pH.

Traditionally, most embryos were transferred at day 2 or 3 following egg collection. There is now good evidence that if embryos are left in extended culture conditions and transferred on day 5 (at the blastocyst stage), higher pregnancy rates can be achieved [9]. Indeed, day 5 or blastocyst transfer is the default position in most units. Approximately 55–60% of all mature eggs fertilize normally and these are graded by the embryologist on day 2 (Fig. 52.2). At present, the guidelines in the UK from the Humam Fertilisation and Embryology Authority (HFEA) state that only two embryos should be transferred in people under the age of 40, unless exceptional circumstances are present, but over the age of 40 three embryos can be transferred. With increasing success rates and concerns over multiple births, many units now electively transfer one embryo if the patient is under 38 years old, unless she has had multiple previous failed cycles. Although this may have a slight effect on success rates, the other normal embryos are frozen and hence if a cycle is unsuccessful, the patient can undergo repeated single embryo transfers from frozen embryo replacement cycles. Evidence from elective single embryo transfer programmes in Scandinavia and Belgium has shown that twin rates can be virtually eliminated whilst maintaining acceptable overall pregnancy rates [10].

The potential benefits of a day 2 transfer are that a single‐stage culture medium can be used and also that the majority of normal embryos survive to this stage. After two or three embryos have been replaced, there may be surplus embryos of a satisfactory quality that are suitable for cryopreservation. The potential downside of a day 2 transfer is that in a normal menstrual cycle, the day 2 embryo is still in the fallopian tube and not in the uterine cavity. Also it is much more difficult to accurately grade a day 2 or 3 embryo. The benefit of a day 5, or blastocyst, transfer is that the embryo has been replaced when it would physiologically be in the uterine cavity –this may have some benefits regarding certain growth factors that can improve embryo development. Blastocyst transfer also allows better selection of embryos as some abnormal embryos perish between day 2 and day 5 (Figs 52.3–52.6).

Embryo transfer is performed without anaesthetic. A Cuscoe’s speculum is generally used to visualize the cervix, which is cleaned carefully, and a sterile single‐use embryo transfer catheter is carefully inserted through the cervical canal. Where in the uterine cavity the embryos are replaced is a topic of great debate, but it is not uncommon for them to be placed in the mid‐cavity portion and generally to stop insertion of the catheter before the fundus where it could potentially cause some slight trauma and bleeding. Evidence suggests that embryo transfer should be performed under ultrasound guidance as this allows more accurate placement of the embryos in the uterine cavity and has been shown to significantly improve success rates [11]. After the outer sheath has been inserted in the correct location, an inner catheter containing the embryos is inserted into the outer sheath. When it is in the correct position a very small aliquot of fluid is used to emit the embryos from the end of the catheter. The inner catheter is then removed and handed back to the embryologist to confirm that no embryos have been retained in the inner catheter. If the catheter is clear, the outer sheath is gently withdrawn and the speculum removed.

Although there is no chance that the embryos can ‘fall out’, many patients are not surprisingly very cautious at this stage and quite often are allowed to rest in a supine position for up to 2 hours before being allowed to leave the hospital. There has been no evidence that leaving the patients in a supine position increases pregnancy rates, but it may help the patients psychologically.

Luteal phase support

With modern assisted conception utilizing either agonist or antagonist protocols, some form of luteal phase support (LPS) is necessary. Although natural cycle IVF does not need this, superovulation may impair normal corpus luteal function and the use of LPS has been shown to improve success rates [12]. The use of LPS with antagonist cycles is more debatable, but pregnancy rates without it are generally thought to be significantly lower [13]. LPS is broadly divided into three types: (i) use of luteotropic preparations such as hCG, (ii) use of progestogens or progesterone and (iii) use of more intense regimens when there has been an agonist trigger. hCG is given by subcutaneous injection in small aliquots that stimulates the patient’s own ovaries to produce more progesterone. It has been shown to be as efficacious as progesterone but does require an injection and also increases the risk of OHSS in some patients.

The use of progesterone is more common and it can be given as tablets, injections, vaginal gel or vaginal pessaries/rectal suppositories. Intravaginal or rectal use of progesterone achieves extremely good tissue levels very rapidly. It is known that LPS should be given for a minimum of 2 weeks, but some clinics routinely offer it up to 12 weeks or even later. However, there is little good evidence that continuing it beyond 2 weeks significantly improves pregnancy rates. The minimum dose is 200 mg/day but the most commonly prescribed dose is 400–800 mg/day.

The more intense regimens utilize injectable intramuscular progesterone with estradiol supplementation, normally in the form of tablets. The progesterone and estradiol are both routinely continued if the pregnancy test is positive. It is not uncommon for the injectable progesterone to be changed to a vaginal preparation at around 8 weeks of gestation because of the pain caused by the repeated deep intramuscular injections required for the oil‐based progesterone preparation.

Pregnancy test

The wait between the embryos being replaced and the pregnancy test is the most psychologically stressful time for the majority of patients. Some patients can start bleeding early, prior to the pregnancy test. Progesterone supplementation can also delay bleeding, even if the pregnancy test is negative. Generally, pregnancy tests are performed around 14 days from embryo transfer and can either be done at home with a urinary pregnancy test or at the clinic with a serum pregnancy test. A home pregnancy test is more convenient for the patient, and the currently available kits have excellent levels of sensitivity down to detection rates of 25 IU. If the pregnancy test is positive and in the normal range, then it is usual to offer the patient a transvaginal scan 2–3 weeks later to ensure that the pregnancy is intrauterine and also to assess its viability. If the initial hCG level is low, then this is often repeated 48 hours later to assess the rise; it if it is suboptimal, then the possibility of an ectopic pregnancy or miscarriage has to be considered and appropriate follow‐up organized.