FEMALE HORMONE PHYSIOLOGY

• References [1,2,10]

FEMALE HORMONES
Estradiol (E2) Reproductive age Estradiol is the primary hormone secreted by the follicle in the ovaries, and it is 12 - 80 times more potent than estrone and estriol Estradiol stimulates development of the female sex organs during puberty, and it causes thickening of the endometrium during the menstrual cycle Normal range: 12.5 - 498 pg/ml depending on the phase of the menstrual cycle Menopause Ovarian estradiol production ceases A small amount is produced by the conversion of adrenal steroids in peripheral fat tissue Normal range: 0 - 55 pg/ml depending on the length of menopause Infertility As women age, ovarian follicles gradually decline. Follicle loss leads to lower estradiol levels and reduced negative feedback on the pituitary. (see HPO axis). FSH levels rise, and this causes elevated estradiol levels in the early follicular phase (see menstrual cycle). To test for ovarian reserve, an estradiol level and an FSH can be checked on Day 3 of the cycle. FSH levels >10 - 15 mIU/ml and estradiol levels >60 - 80 pg/ml suggest low ovarian reserve. See infertility evaluation below.
Estrone (E1) Reproductive age Estrone is not as potent or abundant as estradiol Normal range: 37 - 229 pg/ml depending on the phase of the menstrual cycle Menopause After estradiol levels fall, estrone becomes the predominant estrogen. It is primarily formed from peripheral aromatization of androstenedione in the adrenal gland. Normal range: 14 - 103 pg/ml depending on the length of menopause
Estriol (E3) Reproductive age Estriol is produced by the placenta, and it is the primary estrogen of pregnancy. It has no significant role outside of pregnancy. Menopause No significant role
Progesterone Reproductive age Progesterone is released by the corpus luteum in the ovaries. It causes the endometrium to become secretory, preparing it for ovum implantation. In pregnancy, it is produced by the placenta during the second and third trimesters Normal range: 0.2 - 27 ng/ml depending on the phase of the menstrual cycle Menopause Ovarian progesterone production stops Normal range: 0.1 - 0.8 ng/ml Infertility Progesterone levels measured 1 week prior to expected menses (cycle day 21) can be used to detect ovulation. A level ≥ 3 ng/ml means that ovulation likely occurred. See infertility evaluation below.
Follicle-stimulating hormone (FSH) Reproductive age FSH is released from the anterior pituitary in response to GnRH. FSH stimulates follicles in the ovary to mature. Normal range: 3.5 - 21.5 mIU/ml depending on the phase of the menstrual cycle Menopause Estrogen loss reduces negative feedback in the pituitary and hypothalamus, and FSH levels rise Normal range: 25.8 - 135 mIU/ml Infertility As women age, ovarian follicles gradually decline. Follicle loss leads to lower estradiol levels and reduced negative feedback on the pituitary. (see HPO axis). FSH levels rise, and this causes elevated estradiol levels in the early follicular phase (see menstrual cycle). To test for ovarian reserve, an estradiol level and an FSH can be checked on Day 3 of the cycle. FSH levels >10 - 15 mIU/ml and estradiol levels >60 - 80 pg/ml suggest low ovarian reserve. See infertility evaluation below.
Luteinizing hormone (LH) Reproductive age LH is released from the anterior pituitary in response to GnRH The LH surge in the middle of the menstrual cycle stimulates ovulation LH maintains the corpus luteum and stimulates steroid production Normal range: 2.4 - 95.6 mIU/ml depending on the phase of the menstrual cycle Menopause Estrogen loss reduces negative feedback in the pituitary and hypothalamus, and LH levels rise Normal range: 7.7 - 58.5 mIU/ml
Testosterone Reproductive age Testosterone is produced by the ovaries in small amounts. In the ovaries, aromatase converts testosterone to estradiol. Normal range: 8 - 48 ng/dl Menopause Ovaries continue to produce testosterone Normal range: 3 - 41 ng/dl
Dehydroepiandrosterone (DHEA) Reproductive age DHEA is a mild androgen produced by the adrenal cortex In peripheral tissues, DHEA can be converted into estradiol or testosterone DHEA levels peak around age 30 and then gradually decline DHEA-S is an active metabolite of DHEA that has a much longer half-life. DHEA-S is present in concentrations 300 - 500 times that of DHEA. DHEA levels have a diurnal variation where DHEA-S only has minimal diurnal variation. Because of this, DHEA-S is often the preferred lab for measuring DHEA activity. DHEA-S levels are typically measured to screen for adrenal hyperfunction in women with virilization Normal range: DHEA-S levels vary by age with a peak range of 84 - 378 mcg/dl around age 30 Menopause DHEA production continues to decline with levels falling to 10 - 25% of their peak value by age 70 - 80 years
Anti-Müllerian hormone Reproductive age / Fertility Anti-Müllerian hormone, also called Müllerian-inhibiting hormone, is a hormone produced by granulosa cells in the ovary. Granulosa cells surround eggs and support their development. Anti-Müllerian hormone inhibits follicle recruitment in resting eggs so that a dominant follicle can develop. As the number of eggs in the ovary diminishes, levels of anti-Müllerian hormone decrease. Anti-Müllerian hormone is often used to measure ovarian reserve in women who are trying to conceive. Levels < 1.66 ng/ml are indicative of low ovarian reserve, and levels < 1 ng/ml portend a poor response to ovarian stimulation used in vitro fertilization (IVF). Despite being a marker of ovarian reserve, anti-Müllerian hormone has not been shown to be a good predictor of fertility. See biomarkers of ovarian reserve and infertility below. Normal ranges 20 - 30 years old: median values range from 4.2 - 4.7 ng/ml 30 - 40 years old: median values range from 1.69 - 3.0 ng/ml 40 - 50 years old: median values range from <0.03 - 0.58 ng/ml Menopause Levels are undetectable

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• Phases
• Menses (days 0 - 5) - menses occurs during days 0 - 5 of the typical 28-day menstrual cycle. As the corpus luteum regresses, it stops secreting progesterone and estrogen. This causes the endometrium to necrose and slough off.
• Follicular phase (days 1 - 13) - the follicular phase is the first 13 days of a menstrual cycle, where FSH released by the pituitary stimulates the development of a mature follicle. A developing follicle secretes estradiol up to ovulation, at which point it enters the luteal phase.
• Ovulation (days 13 - 14) - ovulation is the release of an egg from a mature follicle, and it typically occurs on days 13 or 14 of a cycle.
• Luteal phase (days 14 - 28) - the final 14 - 28 days of a cycle are the luteal phase. The evacuated follicle becomes the corpus luteum, which releases progesterone and estrogen. Progesterone causes the endometrium to become secretory, preparing it for ovum implantation. Luteinizing hormone stimulates the corpus luteum until it regresses around days 24 - 26, at which point hormone levels plunge, and the endometrium is no longer supported.

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• Overview
• Menopause occurs when ovarian follicles are depleted, and the production of estrogen and progesterone ceases
• Twelve consecutive months without menses is the definition used to mark the beginning of menopause. The median age of the final menstrual period is 52.5 years. Prior to this, women typically experience years of menstrual irregularities. [9]

• Symptoms
• Amenorrhea
• Hot flushes defined as episodic flushing and warmth of the skin often accompanied by sweating
• Vaginal dryness, burning, and irritation
• Sexual symptoms of diminished lubrication and pain
• Urinary urgency, dysuria, and recurrent urinary tract infections
• Irritability and anxiety
• Fatigue and weakness
• Decreased calcification of the bones (osteoporosis)

• Predicting menopause onset
• Menstrual patterns and biomarkers of ovarian reserve can be used to predict the onset of menopause, although neither one is precise
• In general, women who begin menopause at a younger age have a longer transition period and more symptoms than women who start at an older age

• Menstrual patterns
• Early menopause transition - marked by irregularities of ≥ 7 days in the intermenstrual cycle in women with previously normal cycles. This occurs at a median age of 47 years.
• Late menopause transition - amenorrhea for > 60 days, after which 95% of women will go on to have their final menstrual period within the next 4 years. The median age for the late menopause transition is 49 years.
• Menopause - marked by no menses for 12 consecutive months. The median age for the last menstrual period is 52.5 years, and most women go through menopause between the ages of 47 and 54 years. [9]

• Biomarkers of ovarian reserve
• FSH and Anti-Müllerian hormone (AMH) can both be used to predict menopause onset
• FSH levels increase as ovarian reserve decreases. Ideally, FSH levels should be drawn within the first 5 days of menses when they are at their highest. AMH levels fall as ovarian reserve decreases.
• Results from a study that measured AMH and FSH levels in 313 women before following them longitudinally for the onset of menopause are presented in the tables below

• Reference [8]

% of women achieving menopause within 5 years based on AMH levels
	AMH levels
Age range	Undetectable	0.09 - 1.9 ng/ml	≥ 2.0 ng/ml
40 - 44 years (N=192)	40%	5%	0%
45 - 49 years (N=121)	60%	23%	0%

• FSH levels were drawn on days 1 - 10 of the menstrual cycle in women with normal menstration
• Reference [8]

% of women achieving menopause within 5 years based on FSH levels
	FSH levels
Age range	0 - 5.39 IU/L	5.4 - 13 IU/L	> 13 IU/L
40 - 44 years (N=192)	6%	6%	22%
45 - 49 years (N=121)	31%	23%	46%

• Treatment
• See menopause treatment guidelines and female hormone medications

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• Overview
• Infertility is defined as a failure to achieve pregnancy after 12 months of regular unprotected intercourse. In the U.S., about 8.8% of women aged 15 - 49 years are affected.
• The recommendations below provide a straightforward approach to initiating an infertility evaluation [10]

• Reference [10]

Steps to evaluating infertility
Step 1 - Determine if patient is ovulating A regular menstrual cycle (every 21 - 35 days) with premenstrual symptoms (e.g. breast tenderness, fluid retention) indicates ovulation Irregular menses (cycles < 21 days or > 35 days), amenorrhea, and abnormal uterine bleeding are suggestive of anovulation If ovulation is unclear from patient history, check a serum progesterone on day 21 of the menstrual cycle. A level > 3 ng/ml means ovulation likely occurred.
Step 2 - Order testing based on ovulation status No evidence of ovulation Check TSH, prolactin, FSH, and LH In women with signs of PCOS (e.g. acne, hirsutism, male-pattern hair loss), also order free and total testosterone, DHEA-S, and 17-hydroxyprogesterone (17-OHP) Evidence of ovulation Evaluate ovarian reserve with one or more of the following tests: Anti-Müllerian hormone test - level < 1.66 ng/ml suggests low ovarian reserve FSH and estradiol on Day 3 of cycle - FSH >10 - 15 mIU/ml and estradiol >60 - 80 pg/ml suggests low ovarian reserve Pelvic ultrasound with antral follicle count - antral follicles are resting follicles 2 - 10 mm in diameter that can be seen on an ultrasound. Their sum is directly proportional to the number of eggs remaining in the ovary. A count of < 4 follicles (both ovaries combined) suggests low ovarian reserve. Test partner semen See semen parameters below for more Further testing when indicated Pelvic ultrasound - evaluate for uterine abnormalities Hysterosalpingogram - evaluate for tubal patency
Step 3 - Considerations based on results Abnormal TSH - hypo- or hyperthyroidism should be treated to see if ovulation returns Elevated prolactin - prolactinoma should be treated (surgery or dopamine agonists) to see if ovulation returns PCOS - in obese women, weight loss of ≥ 15% can cause ovulation to return. Metformin may be beneficial for women with type two diabetes or glucose intolerance. Clomiphene is the recommended first-line treatment for infertility in PCOS. Low ovarian reserve - referral to infertility specialist for ovarian stimulation, IVF, etc. Hypogonadotropic hypogonadism (low FSH and LH) - referral to infertility specialist. Pulsatile GnRH therapy can restore ovulation in many women. Exogenous FSH and LH may also be used. Abnormal semen - referral to urologist for further evaluation/treatment Uterine or tubal abnormalities - referral to infertility specialist for further evaluation/treatment

• Reference [Manufacturer's PI, 10]

Infertility drugs
Clomiphene (Clomid®) Mechanism Clomiphene is a selective estrogen receptor modulator (SERM). See SERM activity table for more. Clomiphene blocks estrogen receptors in the hypothalamus (and possibly the pituitary), inhibiting negative feedback from estradiol. GnRH release is increased, leading to higher FSH levels that stimulate follicular development (see HPO axis above). Dosing Starting: 50 mg once daily for 5 days starting on the 5th day of the cycle. For women with no recent menstruation, therapy may be started at any time. Dose may be increased to 100 mg/day in subsequent cycles. In studies, doses up to 150 mg/day have been used. Only 3 cycles are recommended, but it has been used for up to 6 cycles in some studies Dosage form: 50 mg tablet Generic: - YES / less than $50 for 30 tablets Other Side effects include headache (34%), hot flashes (33%), irritability (21%), fatigue (14%), dizziness (7%), thin endometrium (15% - 50%), and visual blurring or other visual symptoms such as spots or flashes (2%). Ovarian hyperstimulation syndrome may occur. Symptoms include abdominal or pelvic pain, weight gain, discomfort, and distention. Increases chance of multiple pregnancies (up to 12.5% in some studies) Use lower dose in PCOS
Letrozole (Femara®) Mechanism In the ovaries, the aromatase enzyme converts testosterone and androstenedione to estradiol. Letrozole inhibits aromatase and blocks the production of estradiol. With decreasing estradiol levels, negative feedback on the pituitary is diminished, and FSH levels rise, stimulating follicular development (see HPO axis above). Dosing Dosing: 2.5 - 5 mg once daily for 5 days starting on Day 3 - 5 of the menstrual cycle Doses up to 7.5 mg/day have been used in studies Has been used for up to 5 cycles in studies Dosage form: 2.5 mg tablet Generic: - YES / less than $50 for 30 tablets Other Letrozole is FDA-approved as an adjuvant treatment in breast cancer. Use in infertility is off-label. Side effects include headache (41%), fatigue (21.7%), hot flashes (20.3%), irritability (18%), dizziness (12.3%), abdominal bloating, and breast pain Ovarian hyperstimulation syndrome may occur. Symptoms include abdominal or pelvic pain, weight gain, discomfort, and distention. Increases chance of multiple pregnancies (up to 14.3% in some studies)
Gonadotropins (Gonal-f®, Menopur®) Mechanism Gonadotropins (FSH and LH) are available in several injectable preparations FSH stimulates follicular development, and LH maintains the corpus luteum (see HPO axis above) Gonal-f is FSH made from recombinant DNA Menopur is 1:1 mixture of FSH and LH. Menopur is extracted from the urine of postmenopausal women. Dosing Gonadotropin is injected daily starting on Day 3 - 5 of the menstrual cycle Ovarian response is monitored by ultrasound Once appropriate follicular development is observed, hCG is injected to stimulate ovulation Injections are very expensive Other May cause abdominal bloating (27 - 34%), injection site reactions (10%), and breast pain Ovarian hyperstimulation syndrome may occur. Symptoms include abdominal or pelvic pain, weight gain, discomfort, and distention. Increases chance of multiple pregnancies (up to 36% in some studies)

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• RCT
  FSH vs Clomiphene ± Intrauterine Insemination (IUI) in Unexplained Infertility, Lancet (2018) [PubMed abstract]
• Design: Randomized, controlled trial (N=666, length = up to 6 cycles) in women who had used clomiphene for 6 cycles and not conceived
• Treatment: FSH + HCG vs Clomiphene 50 - 150 mg/day. Both groups were also randomly assigned to IUI or regular intercourse.
• Primary outcome: Conception leading to livebirth within 8 months after randomisation, defined as any baby born alive with a gestational age beyond 24 weeks
• Results:
• Livebirth: FSH/HCG + IUI - 54%, FSH/HCG + intercourse - 48%, Clomiphene + IUI - 44%, Clomiphene + intercourse - 39% (FSH/HCG vs Clomiphene p=0.0124 | IUI vs intercourse p=0.12)
• Findings: In women with normogonadotropic anovulation and clomiphene citrate failure, a switch of treatment to gonadotropins increased the chance of livebirth over treatment with clomiphene citrate; there was no evidence that addition of intrauterine insemination does so.

• RCT
  Clomiphene or Letrozole + Intrauterine Insemination (IUI) vs Expectant Management for Unexplained Infertility, Lancet (2018) [PubMed abstract]
• Design: Randomized, controlled trial (N=201, length = up to 3 cycles) in women with unexplained infertility
• Treatment: Clomiphene 50 - 150 mg/day or letrozole 2.5 - 7.5 mg/day for 5 days + IUI vs Expectant management (no intervention)
• Primary outcome: Cumulative live birth rate in the intention-to-treat population
• Results:
• Live birth: Ovarian stimulation + IUI - 31%, Expectant management - 9% (p=0.0003)
• Clinical pregnancy: Ovarian stimulation + IUI - 37%, Expectant management - 11% (p<0.0001)
• Multiple pregnancies (out of live births): Ovarian stimulation + IUI - 6%, Expectant management - 0%
• Findings: IUI with ovarian stimulation is a safe and effective treatment for women with unexplained infertility and an unfavourable prognosis for natural conception

• RCT
  Letrozole vs Clomid vs Gonadotropin (Menopur) for Unexplained Infertility, NEJM (2015) [PubMed abstract]
• Design: Randomized, controlled trial (N=900, length = up to 4 cycles) in women with unexplained infertility
• Treatment: Letrozole 2.5 - 7.5 mg/day for 5 days vs Clomiphene 100 mg/day for 5 days vs Gonadotropin (Menopur) daily until hCG | All groups received 10,000 IU of hCG upon follicle development | All groups received intrauterine insemination
• Primary outcome: Rate of multiple gestations among women with clinical pregnancies
• Results:
• Multiple gestations (among clinical pregnancies): Gonadotropin - 32%, Clomiphene - 9%, Letrozole - 13%
• Clinical pregnancy: Gonadotropin - 36%, Clomiphene - 28%, Letrozole - 22%
• Live births (among all women): Gonadotropin - 32%, Clomiphene - 23%, Letrozole - 19%
• Findings: In women with unexplained infertility, ovarian stimulation with letrozole resulted in a significantly lower frequency of multiple gestation but also a lower frequency of live birth, as compared with gonadotropin but not as compared with clomiphene.

• RCT
  Clomiphene vs FSH vs Immediate IVF for Unexplained Infertility, Fertil Steril (2014) [PubMed abstract]
• Design: Randomized, controlled trial (N=154, length = up to 2 cycles) in women with > 6 months of unexplained infertility
• Treatment: Clomiphene 100 mg/day for 5 days vs FSH 300 IU/day for 3 days vs Immediate IVF | Clomiphene group received 10,000 IU of hCG if necessary | FSH groups received 10,000 IU of hCG upon follicle development | Clomiphene/FSH groups received intrauterine insemination
• Primary outcome: Proportion with a clinically recognized pregnancy, number of treatment cycles, and time to conception after two treatment cycles and at the end of treatment.
• Results:
• Clinical pregnancy: Clomiphene - 22%, FSH - 17%, IVF - 49%
• Live births: Clomiphene - 16%, FSH - 14%, IVF - 31%
• Findings: A randomized controlled trial in older women with unexplained infertility to compare treatment initiated with two cycles of controlled ovarian hyperstimulation/IUI versus immediate IVF demonstrated superior pregnancy rates with fewer treatment cycles in the immediate IVF group.

• OBS
  Birth Outcomes in Medically Assisted Reproduction vs Natural Reproduction, Lancet (2019) [PubMed abstract]
• Design: Registry cohort study (N=65,723, length = 5 years) in households with at least one child aged 0 - 14 years
• Exposure: Medically assisted reproduction (ovulation induction, artificial insemination, IVF, and/or ICSI with fresh or frozen embryo transfers) vs Natural reproduction
• Primary outcome: Birthweight, gestational age, risk of low birthweight, and risk of preterm birth
• Results:
• Birthweight (grams): Medically assisted - 3286, Natural - 3551 (p<0.0001)
• Low birthweight: Medically assisted - 13%, Natural - 3% (p<0.0001)
• Gestational age (days): Medically assisted - 271, Natural - 278 (p<0.0001)
• Preterm birth: Medically assisted - 15%, Natural - 5% (p<0.0001)
• Findings: Children conceived by medically assisted reproduction face an elevated risk of adverse birth outcomes. However, our results indicate that this increased risk is largely attributable to factors other than the medically assisted reproduction treatment itself

• OBS
  Association Between Fertility Treatment and Cancer Risk in Children, JAMA (2019) [PubMed abstract]
• Design: Registry cohort study (N=1,085,172 | length = 11.3 years) in Danish children born between 1996 and 2012
• Exposure: Maternal fertility treatment including the use of fertility drugs (clomiphene, gonadotropins, gonadotropin-releasing hormone analogs, human chorionic gonadotropin, progesterone, and estrogen) and assisted reproductive technology (in vitro fertilization, intracytoplasmic sperm injection, and frozen embryo transfer) vs None
• Primary outcome: Hazard ratios and incidence rate differences for childhood cancer
• Results:
• Only frozen embryo transfer showed a significantly higher incidence of cancer compared to no treatment. (Incidence rate difference, 26.9 cases/100000 children, 95%CI[2.8 - 51.0])
• Findings: Among children born in Denmark, the use of frozen embryo transfer, compared with children born to fertile women, was associated with a small but statistically significant increased risk of childhood cancer; this association was not found for the use of other types of fertility treatment examined.

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• RCT
  Letrozole vs Clomiphene for Infertility in PCOS, NEJM (2014) [PubMed abstract]
• Design: Randomized controlled trial (N=750, length = up to 5 cycles) in infertile women with PCOS
• Treatment: Letrozole 2.5 - 7.5 mg/day for 5 days vs Clomiphene 50 - 150 mg/day for 5 days | Both drugs were started on cycle day 3
• Primary outcome: Live births during the treatment period
• Results:
• Live births: Letrozole - 27.5%, Clomiphene - 19.1% (p=0.007)
• Twin live births: Letrozole - 3.4%, Clomiphene - 7.4% (p=0.32)
• Findings: As compared with clomiphene, letrozole was associated with higher live-birth and ovulation rates among infertile women with the polycystic ovary syndrome.

• RCT
  Clomiphene vs Metformin vs Clomiphene + Metformin for Infertility in PCOS, NEJM (2007) [PubMed abstract]
• Design: Randomized controlled trial (N=626, length = up to 6 months) in infertile women with PCOS
• Exposure: Metformin 1000 mg twice daily vs Clomiphene 50 - 150 mg/day for 5 days beginning on day 3 of menses vs Both treatments
• Primary outcome: Rate of live births
• Results:
• Live births: Clomiphene - 23%, Metformin 7%, Clomiphene + Metformin - 27% (p<0.001 for metformin vs both clomiphene and combination therapy | p=0.31 for clomiphene vs combination therapy)
• Multiple pregnancies (among all pregnancies): Clomiphene - 6%, Metformin 0%, Clomiphene + Metformin - 3%
• Findings: Clomiphene is superior to metformin in achieving live birth in infertile women with the polycystic ovary syndrome, although multiple birth is a complication.

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• RCT
  Preimplantation Genetic Testing for Aneuploidy vs None, NEJM (2021) [PubMed abstract]
• Design: Randomized controlled trial (N=1212 | length = 1 year) in women aged 20 - 37 years with subfertility and the availability of three or more good-quality blastocysts (defined as having good morphologic criteria)
• Treatment: Preimplantation genetic testing for aneuploidy (PGT-A) vs None. Only single frozen-embryo transfers were performed each time. Women could receive up to 3 transfers within a year.
• Primary outcome: Cumulative livebirth rate that resulted from up to three embryo transfers performed within 1 year after randomization
• Results:
• Primary outcome: PGT-A - 77.2%, None - 81.8% (HR 0.94, 95%CI [0.89 - 1.00])
• Cumulative pregnancy loss: PGT-A - 8.7%, None - 12.6% (HR 0.69, 95%CI [0.49 - 0.98])
• Good birth outcome: PGT-A - 62.4%, None - 63.5% (HR 0.98, 95%CI [0.90 - 1.07])
• Good birth outcome defined as a live birth at 37 weeks or more of gestation, with a birth weight between 2500 and 4000 g and without a major congenital anomaly.
• Findings: Among women with three or more good-quality blastocysts, conventional IVF resulted in a cumulative live-birth rate that was noninferior to the rate with PGT-A.

• RCT
  Intracytoplasmic Sperm Injection vs Conventional IVF, Lancet (2021) [PubMed abstract]
• Design: Randomized controlled trial (N=1064, length = 1 transfer) in couples who had undergone ≤ 2 previous conventional IVF or intracytoplasmic sperm injection attempts where the male had normal sperm count and mobility
• Treatment: Intracytoplasmic sperm injection vs Conventional IVF
• Primary outcome: Livebirth after the first embryo transfer from the initiated cycle
• Results:
• Live births: Intracytoplasmic injection - 35%, Conventional IVF - 31% (p=0.27)
• Findings: In couples with infertility in whom the male partner has a normal total sperm count and motility, intracytoplasmic sperm injection did not improve the livebirth rate compared with conventional IVF. Our results challenge the value of the routine use of intracytoplasmic sperm injection in assisted reproduction techniques for this population.

• RCT
  Physiological, hyaluronan-selected ICSI vs Standard ICSI for infertility treatment, Lancet (2019) [PubMed abstract]
• Design: Randomized controlled trial (N=2772, length = 1 transfer of 1 - 3 fresh embryos) in women undergoing IVF with embryos formed from intracytoplasmic sperm injection (ICSI)
• Treatment: Hyaluronan-based sperm selection for ICSI (so-called physiological ICSI [PICSI]) vs standard ICSI
• Primary outcome: Full-term (≥37 weeks’ gestational age) livebirth
• Results:
• Live births: Physiological ICSI (PICSI) - 27.4%, Standard ICSI - 25.2% (p=0.18)
• Findings: Compared with ICSI, PICSI does not significantly improve term livebirth rates. The wider use of PICSI, therefore, is not recommended at present.

• RCT
  TLT vs EEVA-TLT vs No TLT for Embryo Selection in IVF, Lancet (2023) [PubMed abstract]
• Definitions: Time-lapse embryo culture technology (TLT) is an embryo selection method that allows the continuous, dynamic assessment of embryo morphological changes without the need to remove embryos from the incubator. Early Embryo Viability Assessment (EEVA) is a type of TLT that uses an algorithm for assessing embryos in the first 3 days of growth.
• Design: Randomized controlled trial (N=1731, length = 12 months) in couples undergoing IVF or intracytoplasmic sperm injection
• Treatment: TLT vs EEVA-TLT vs No TLT
• Primary outcome: The co-primary endpoints were the cumulative ongoing pregnancy rate within 12 months in all women and the ongoing pregnancy rate after fresh single embryo transfer in a good prognosis population
• Results:
• 12-month cumulative pregnancy rate: TLT - 50.9%, EEVA-TLT - 50.8%, No TLT - 49.4% (p=0.85)
• Good prognosis population: TLT - 36.8%, EEVA-TLT - 38.2%, No TLT - 37.8% (p=0.90)
• Findings: Neither time-lapse-based embryo selection using the EEVA test nor uninterrupted culture conditions in a time-lapse incubator improved clinical outcomes compared with routine methods. Widespread application of time-lapse monitoring for fertility treatments with the promise of improved results should be questioned.

• RCT
  Timing by Endometrial Receptivity Testing vs Standard Timing in IVF, JAMA (2022) [PubMed abstract]
• Design: Double-blind, randomized controlled trial (N=767 | length = 1 transfer) in women undergoing IVF with a euploid blastocyst(s)
• Treatment: Receptivity-timed frozen embryo transfer with adjusted duration of progesterone exposure prior to transfer vs Standard timing
• Primary outcome: Live birth
• Results:
• Live births: Receptivity timing - 58.5%, Standard timing - 61.9% (p=0.38)
• Findings: Among patients for whom in vitro fertilization yielded a euploid blastocyst, the use of receptivity testing to guide the timing of frozen embryo transfer, compared with standard timing for transfer, did not significantly improve the rate of live birth. The findings do not support routine use of receptivity testing to guide the timing of embryo transfer during in vitro fertilization.

• RCT
  Endometrial Scratching vs None Before IVF, NEJM (2019) [PubMed abstract]
• Design: Randomized controlled trial (N=1364, length = 1 transfer) in women planning IVF with their own oocytes
• Treatment: Endometrial scratching vs No endometrial scratching
• Primary outcome: Live birth
• Results:
• Live births: Endometrial scratching - 26.1%, No endometrial scratching - 26.1%
• Findings: Endometrial scratching did not result in a higher rate of live birth than no intervention among women undergoing IVF

• RCT
  Transfer of Frozen vs Fresh Embryos in IVF, NEJM (2018) [PubMed abstract]
• Design: Randomized controlled trial (N=2157, length = 1 transfer) in ovulatory women with infertility due to tubal factors, male factors, or both
• Treatment: Transfer of fresh embryos vs frozen embryos
• Primary outcome: Live birth (≥ 28 weeks gestation) after the first transfer
• Results:
• Live births: Frozen - 49%, Fresh - 50% (p=0.50)
• Findings: The live-birth rate did not differ significantly between fresh-embryo transfer and frozen-embryo transfer among ovulatory women with infertility, but frozen-embryo transfer resulted in a lower risk of the ovarian hyperstimulation syndrome.

• RCT
  Transfer of Frozen vs Fresh Embryos in IVF in Women Without PCOS, NEJM (2018) [PubMed abstract]
• Design: Randomized controlled trial (N=782, length = 1 transfer) in infertile women without PCOS
• Treatment: Transfer of fresh embryos vs frozen embryos
• Primary outcome: Pregnancy after first transfer defined as pregnancy with a detectable heart rate after 12 weeks of gestation
• Results:
• Live births: Frozen - 36%, Fresh - 35% (p=0.65)
• Findings: Among infertile women without the polycystic ovary syndrome who were undergoing IVF, the transfer of frozen embryos did not result in significantly higher rates of ongoing pregnancy or live birth than the transfer of fresh embryos.

• RCT
  Transfer of Frozen vs Fresh Single Blastocyst in IVF, Lancet (2019) [PubMed abstract]
• Design: Randomized controlled trial (N=1650, length = 1 transfer) in women with regular menstrual cycles undergoing their first cycle of IVF
• Treatment: Single fresh blastocyst transfer vs Single frozen blastocyst transfer
• Primary outcome: Singleton livebirth rate
• Results:
• Live births: Frozen - 50%, Fresh - 40% (p<0.0001)
• Findings: Frozen single blastocyst transfer resulted in a higher singleton livebirth rate than did fresh single blastocyst transfer in ovulatory women with good prognosis. The increased risk of pre-eclampsia after frozen blastocyst transfer warrants further studies.

• RCT
  Freeze-all Embryos vs Fresh Transfer of an Embryo in Women with Fertility Issues, BMJ (2020) [PubMed abstract]
• Design: Randomized controlled trial (N=460, length = 1 transfer) in women with regular menstrual cycles undergoing IVF (cycles 1, 2, or 3) for male, tubal, uterine, or unexplained infertility
• Treatment: Freeze-all embryos and transfer one after one completed menstrual cycle vs Transfer fresh embryo on day 5 of culture
• Primary outcome: Ongoing pregnancy rate defined as a detectable fetal heart beat after eight weeks of gestation
• Results:
• Primary outcome: Freeze-all - 27.8%, Fresh - 29.6% (p=0.76)
• No significant differences between groups were observed for positive human chorionic gonadotropin rate or pregnancy loss, and none of the women had severe ovarian hyperstimulation syndrome
• Findings: In women with regular menstrual cycles, a freeze-all strategy with gonadotropin releasing hormone agonist triggering for final oocyte maturation did not result in higher ongoing pregnancy and live birth rates than a fresh transfer strategy. The findings warrant caution in the indiscriminate application of a freeze-all strategy when no apparent risk of ovarian hyperstimulation syndrome is present.

• OBS
  Association of IVF With Childhood Cancer in the United States, JAMA Pediatrics (2019) [PubMed abstract]
• Design: Retrospective cohort study (N=2,542,533, length = 10 years) in children born in the United States
• Exposure: Conceived via IVF vs Not conceived via IVF
• Primary outcome: Cancer diagnosed in the first decade of life
• Results:
• Cancer rate (per 1,000,000 person-years): IVF - 252, Non-IVF - 193 (HR 1.17; 95%CI [1.00-1.36])
• Findings: This study found a small association of IVF with overall cancers of early childhood, but it did observe an increased rate of embryonal cancers, particularly hepatic tumors, that could not be attributed to IVF rather than to underlying infertility. Continued follow-up for cancer occurrence among children conceived via IVF is warranted.

• RCT
  Prednisone vs Placebo for Live Birth in Recurrent IVF Failure, JAMA (2023) [PubMed abstract]
• Design: Randomized, placebo-controlled trial (N=715 | length = 1 round) in women who had a history of 2 or more unsuccessful embryo transfer cycles, were younger than 38 years when oocytes were retrieved, and were planning to undergo frozen-thawed embryo transfer with the availability of good-quality embryos
• Treatment: Prednisone 10 mg once daily vs Placebo from the day at which they started endometrial preparation for frozen-thawed embryo transfer through early pregnancy
• Primary outcome: Live birth, defined as the delivery of any number of neonates born at 28 or more weeks' gestation with signs of life
• Results:
• Primary outcome: Prednisone - 37.8%, Placebo - 38.8% (p=0.78)
• Findings: Among patients with recurrent implantation failure, treatment with prednisone did not improve live birth rate compared with placebo. Data suggested that the use of prednisone may increase the risk of preterm delivery and biochemical pregnancy loss. Our results challenge the value of prednisone use in clinical practice for the treatment of recurrent implantation failure.

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• OBS
  Association Between Biomarkers of Ovarian Reserve and Infertility Among Older Women of Reproductive Age, JAMA (2017) [PubMed abstract]
• Design: Prospective cohort study (N=750, length = up to 12 cycles) in women aged 30 to 44 years without a history of infertility who had been trying to conceive for ≤ 3 months
• Measured variables: Early-follicular-phase serum level of Antimüllerian hormone (AMH), follicle-stimulating hormone (FSH), and inhibin B and urinary level of FSH
• Primary outcome: Cumulative probability of conception by 6 and 12 cycles of attempt and relative fecundability (probability of conception in a given menstrual cycle). Conception was defined as a positive pregnancy test result.
• Results:
• Conception during study (% of women) by Antimüllerian hormone level
• < 0.7 ng/ml (N=84): 63%
• 0.7 - 8.4 ng/ml (N=579): 66%
• ≥ 8.5 ng/ml (N=74): 59%
• Findings: Among women aged 30 to 44 years without a history of infertility who had been trying to conceive for 3 months or less, biomarkers indicating diminished ovarian reserve compared with normal ovarian reserve were not associated with reduced fertility. These findings do not support the use of urinary or blood follicle-stimulating hormone tests or antimüllerian hormone levels to assess natural fertility for women with these characteristics.

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