without waiting for it to liquefy, although a collection cup may also be used. other methods may be used to insert semen into the vagina notably involving different uses of a conception cap. these include a specially designed conception cap with a tube attached which may be inserted empty into the vagina after which liquefied semen is poured into the tube. these methods are designed to ensure that semen is inseminated as close as possible to the cervix and that it is kept in place there to increase the chances of conception. intrauterine intrauterine insemination (iui) involves injection of washed sperm directly into the uterus with a catheter. insemination in this way means that the sperm do not have to swim through the cervix which is coated with a mucus layer. this layer of mucus can slow down the passage of sperm and can result in many sperm perishing before they can enter the uterus. donor sperm is sometimes tested for mucus penetration if it is to be used for ici inseminations but partner sperm may or may not be able to pass through the cervix. in these cases, the use of iui can provide a more efficient delivery of the sperm. in general terms, iui is usually regarded as more efficient than ici or ivi. it is therefore the method of choice for single and lesbian women wishing to conceive using donor sperm since this group of recipients usually require artificial insemination because they do not have a male partner, not because they have medical problems. owing to the high number of these recipients using donor sperm services, iui is therefore the most popular method of insemination today at a fertility clinic. the term 'artificial insemination' has, in many cases, come to mean iui insemination. it is important that washed sperm is used because unwashed sperm may elicit uterine cramping, expelling the semen and causing pain, due to content of prostaglandins. (prostaglandins are also the compounds responsible for causing the myometrium to contract and expel the menses from the uterus, during menstruation.) resting on the table for fifteen minutes after an iui is optimal for the woman to increase the pregnancy rate. using this technique, as with ici, fertilisation takes place naturally in the external part of the fallopian tubes in the same way that occurs following intercourse. for heterosexual couples, the indications to perform an intrauterine insemination are usually a moderate male factor, the incapability to ejaculate in vagina and an idiopathic infertility. a short period of ejaculatory abstinence before intrauterine insemination is associated with higher pregnancy rates. for the man, a tms of more than 5 million per ml is optimal. in practice, donor sperm will satisfy these criteria and since iui is a more efficient method of artificial insemination than ici and, because of its generally higher success rate, iui is usually the insemination procedure of choice for single women and lesbians using donor semen in a fertility centre. lesbians and single women are less likely to have fertility issues of their own and enabling donor sperm to be inserted directly into the womb will often produce a better chance of conceiving. lesbian couples may either select a friend or family member as their sperm donor or choose an anonymous donor. after a donor sperm is selected, a couple can proceed with donor sperm iui. iui is the least expensive option for same-sex couples and can be done without the use of medication. according to a study from 2021, lesbian women undergoing iui had a clinical pregnancy rate of 13.2% per cycle and 42.2% success rate given the average number of cycles at 3.6. unlike ici, intrauterine insemination normally requires a medical practitioner to perform the procedure. one of the requirements is to have at least one permeable tube, proved by hysterosalpingography. the infertility duration is also important. a female under 30 years of age has optimal chances with iui; a promising cycle is one that offers two follicles measuring more than 16 mm, and estrogen of more than 500 pg/ml on the day of hcg administration. however, gnrh agonist administration at the time of implantation does not improve pregnancy outcome in intrauterine insemination cycles according to a randomized controlled trial. one of the prominent private clinic in europe has published a data a multiple logistic regression model showed that sperm origin, maternal age, follicle count at hcg administration day, follicle rupture, and the number of uterine contractions observed after the second insemination procedure were associated with the live-birth rate the steps to follow in order to perform an intrauterine insemination are: mild controlled ovarian stimulation (cos): there is no control of how many oocytes are at the same time when stimulating ovulation. for that reason, it is necessary to check the amount being ovulated via ultrasound (checking the amount of follicles developing at the same time) and administering the desired amount of hormones. ovulation induction: using substances known as ovulation inductors. semen capacitation: wash and centrifugation, swim-up, or gradient. the insemination should not be performed later than an hour after capacitation. 'washed sperm' may be purchased directly from a sperm bank if donor semen is used, or 'unwashed semen' may be thawed and capacitated before performing iui insemination, provided that the capacitation leaves a minimum of, usually, five million motile sperm. luteal phase support: a lack of progesterone in the endometrium could end a pregnancy. to avoid that 200 mg/day of micronized progesterone are administered via vagina. if there is pregnancy, this hormone is kept administering until the tenth week of pregnancy. iui can be used in conjunction with controlled ovarian hyperstimulation (coh). clomiphene citrate is the first line, letrozole is second line, in order to stimulate ovaries before moving on to ivf. still, advanced maternal age causes decreased success rates; women aged 38–39 years appear to have reasonable success during the first two cycles of ovarian hyperstimulation and iui. however, for women aged over 40 years, there appears to be no benefit after a single cycle of coh/iui. medical experts therefore recommend considering in vitro fertilization after one failed coh/iui cycle for women aged over 40 years. a double intrauterine insemination theoretically increases pregnancy rates by decreasing the risk of missing the fertile window during ovulation. however, a randomized trial of insemination after ovarian hyperstimulation found no difference in live birth rate between single and double intrauterine insemination. a cochrane found uncertain evidence about the effect of iui compared with timed intercourse or expectant management on live birth rates but iui with controlled ovarian hyperstimulation is probably better than expectant management. due to the lack of reliable evidence from controlled clinical trials, it is not certain which semen preparation techniques are more effective (wash and centrifugation; swim-up; or gradient) in terms of pregnancy and live birth rates. intrauterine tuboperitoneal intrauterine tuboperitoneal insemination (iutpi) involves injection of washed sperm into both the uterus and fallopian tubes. the cervix is then clamped to prevent leakage to the vagina, best achieved with a specially designed double nut bivalve (dnb) speculum. the sperm is mixed to create a volume of 10 ml, sufficient to fill the uterine cavity, pass through the interstitial part of the tubes and the ampulla, finally reaching the peritoneal cavity and the pouch of douglas where it would be mixed with the peritoneal and follicular fluid. iutpi can be useful in unexplained infertility, mild or moderate male infertility, and mild or moderate endometriosis. in non-tubal sub fertility, fallopian tube sperm perfusion may be the preferred technique over intrauterine insemination. intratubal intratubal insemination (iti) involves injection of washed sperm into the fallopian tube, although this procedure is no longer generally regarded as having any beneficial effect compared with iui. iti however, should not be confused with gamete intrafallopian transfer, where both eggs and sperm are mixed outside the woman's body and then immediately inserted into the fallopian tube where fertilization takes place. pregnancy rate approximate pregnancy rate as a function of total sperm count (may be twice as large as total motile sperm count). values are for intrauterine insemination. (old data, rates are likely higher these days) the rates of successful pregnancy for artificial insemination are 10-15% per menstrual cycle using ici, and 15–20% per cycle for iui. in iui, about 60 to 70% have achieved pregnancy after 6 cycles. however, these pregnancy rates may be very misleading, since many factors have to be included to give a meaningful answer, e.g. definition of success and calculation of the total population. these rates can be influenced by age, overall reproductive health, and if the patient had an orgasm during the insemination. the literature is conflicting on immobilization after insemination has increasing the chances of pregnancy previous data suggests that it is statistically significant for the patient to remain immobile for 15 minutes after insemination, while another review article claims that it is not. a point of consideration, is that it does cost the patient or healthcare system to remain immobile for 15 minutes if it does increase the chances. for couples with unexplained infertility, unstimulated iui is no more effective than natural means of conception. the pregnancy rate also depends on the total sperm count, or, more specifically, the total motile sperm count (tmsc), used in a cycle. the success rate increases with increasing tmsc, but only up to a certain count, when other factors become limiting to success. the summed pregnancy rate of two cycles using a tmsc of 5 million (may be a tsc of ~10 million on graph) in each cycle is substantially higher than one single cycle using a tmsc of 10 million. however, although more cost-efficient, using a lower tmsc also increases the average time taken to achieve pregnancy. women whose age is becoming a major factor in fertility may not want to spend that extra time. samples per child the number of samples (ejaculates) required to give rise to a child varies substantially from person to person, as well as from clinic to clinic. however, the following equations generalize the main factors involved: for intracervical insemination: n = v s × c × r s n r \times c\times r_ n is how many children a single sample can give rise to. vs is the volume of a sample (ejaculate), usually between 1.0 ml and 6.5 ml c is the concentration of motile sperm in a sample after freezing and thawing, approximately 5–20 million per ml but varies substantially rs is the pregnancy rate per cycle, between 10% and 35% nr is the total motile sperm count recommended for vaginal insemination (vi) or intra-cervical insemination (ici), approximately 20 million pr. ml. the pregnancy rate increases with increasing number of motile sperm used, but only up to a certain degree, when other factors become limiting instead. derivation of the equation (click at right to view) in the simplest form, the equation reads: n = n s n c × r s \times r_ n is how many children a single sample can give rise to ns is the number of vials produced per sample nc is the number of vials used in a cycle rs is the pregnancy rate per cycle ns can be further split into: n s = v s v v = ns is the number of vials produced per sample vs is the volume of a sample vv is the volume of the vials used nc may be split into: n c = n r n s = nc is the number of vials used in a cycle nr is the number of motile sperm recommended for use in a cycle ns is the number of motile sperm in a vial ns may be split into: n s = v v × c =v_\times c} ns is the number of motile sperm in a vial vv is the volume of the vials used c is the concentration of motile sperm in a sample thus, the factors can be presented as follows: n = v s × c × r s n r × v v v v \times c\times r_\times n is how many children a single sample can help giving rise to vs is the volume of a sample c is the concentration of motile sperm in a sample rs is the pregnancy rate