Early Pregnancy
Michele Kiely in Reproductive and Perinatal Epidemiology, 2019
The corpus luteum (or “yellow body”) is a temporary mass of yellow tissue on the surface of the ovary, formed each cycle from the remnants of the ruptured follicle. The corpus luteum is responsible for production of progesterone (literally, the hormone “supporting pregnancy”). Progesterone stimulates the endometrial lining of the uterus so that it will be primed for implantation. The second half of the menstrual cycle (from ovulation to onset of next menses) is called the luteal phase because the woman’s hormonal milieu is dominated by progesterone from the corpus luteum. The length of the luteal phase is relatively predictable: by 7 to 10 days after ovulation, the corpus luteum begins to regress and progesterone levels begin to fall. If there is no pregnancy, the corpus luteum ceases to function by about the fourteenth day after ovulation. Progesterone production ends, and the uterine lining is shed in menstrual bleeding.
Female infertility
David M. Luesley, Mark D. Kilby in Obstetrics & Gynaecology, 2016
A history of regular periods usually indicates ovulation. However, a reliable marker is useful to confirm that ovulation has occurred. After the release of the oocyte and the formation of the corpus luteum, progesterone levels rise sharply, reaching a peak level approximately 8 days after the LH surge. The detection of high levels of progesterone in serum or evidence of progesterone effect can be used as a secondary marker of ovulation. Historically, the effects of progesterone on basal body temperature, endometrial histology or cervical mucus were commonly used. Measuring serum progesterone at its peak in the mid-luteal phase is a reliable, safe and inexpensive test. Levels in excess of 30 nmol/L are diagnostic of ovulation [C]; however, lower (suboptimal) levels may be due to incorrect timing of blood sampling or may be caused by a luteinised unruptured follicle. It is important to remember that the mid-luteal phase is approximately 7 days before the next expected period i.e. day 21 and day 28 in 28-day and 35-day cycles, respectively.
Reproductive Biotechnologies Applied to Artificial Insemination in Swine
Juan Carlos Gardón, Katy Satué in Biotechnologies Applied to Animal Reproduction, 2020
Before illustrating the possible methods to perform estrus detection, it is important to understand the oestrus cycle in porcine females. The oestrus cycle lasts 21 days and it is divided into two stages: 1) the follicular phase which is split in proestrus and oestrus (1–3 days both of them); 2) the luteal phase divided in metoestrus and dioestrus (2–3 days and 13–18 days, respectively). The estrus stage can last from 36 to 90 h, depending mainly on the age of the sow (Steverink et al., 1999), and it is characterized by hormonal changes, in particular, an increase in estrogen levels. Following the peak of estrogen (24–48 h before estrus) (Guthrie et al., 1972), vulvar edema is observed and, subsequently, 36–40 h after the first estrus signals, the ovulation occurs (Yeste and Castillo-Martín, 2013). The main rules that should be considered to perform the estrus detection are the following: 1) prefer the early hours of the morning and before feeding; 2) expose the sow to the presence and/or smell of a boar, because sows show a procreative behavior in presence of the male (de Jonge et al., 1994); 3) handle the sow calmly to allow relaxing (Sterle and Safranski, 2000).
Systemic vascular resistance may influence the outcome of in vitro fertilization
Published in Gynecological Endocrinology, 2022
Francesco Galanti, Ilaria Pisani, Serena Riccio, Daniele Farsetti, Barbara Vasapollo, Gian Paolo Novelli, Donatella Miriello, Rocco Rago, Herbert Valensise
Ultra Sonic Cardiac Output Monitor (USCOM ® - Australia LTD) was used to detect the following hemodynamic parameters: stroke volume (SV), CO, heart rate (HR), SVR, inotropy index (INO) and time flow correct (TFC) [18]. USCOM evaluations were performed with the women in the supine position, after at least 5 min of rest. SVR was calculated automatically by USCOM after the introduction of SBP (systolic blood pressure) and DBP (diastolic blood pressure) according to the following formula: SVR = MBP (mmHg)/CO (L/min) × 80. SBP and DBP were measured form the brachial artery with an automatic blood pressure monitor. USCOM assessments were performed at two different moments: 1. mid-luteal phase, between seven/ten days before the beginning of menstruation and of the subsequently ovarian stimulation/endometrial preparation; 2. at the day of embryo transfer (dET). Patients were than divided according to the eventual onset of pregnancy (evaluated by a blood positive bHCG test). After the embryo-transfer, the luteal phase support was guaranteed by the administration of vaginal progesterone 800 mg/die, until at least blood β-HCG testing.
Luteal-phase progesterone supplementation in non-IVF treatment: a survey of physicians providing infertility treatment
Published in Human Fertility, 2020
Elizabeth Weedin, Jonathan Kort, Alexander Quaas, Valerie Baker, Robert Wild, Karl Hansen
For patients undergoing non-IVF infertility treatments, patient request was the most common indication for an REI to prescribe luteal phase progesterone support: 75.4% compared to 33.3% of OB/GYNs (p < 0.0001; Figure 1). Of the general OB/GYN respondents, the most common diagnosis for progesterone supplementation was recurrent pregnancy loss, 75% (not significant when compared to REIs; Figure 1). Significant differences between the two groups were also observed for the diagnosis of short luteal phase (73.8% of REIs, 52.8% of OB/GYNs) (p = 0.046, Figure 1). Additional clinical indications reported in the ‘other’ category were predominantly related to low serum progesterone or gonadotropin with IUI treatments. Also, when asked to describe how participating physicians defined a short luteal phase, responses were variable but most commonly, respondents reported defining short luteal phase as <10–12 days. However, alternate answers included timing by endometrial biopsy or providers acknowledging the absence of use of this term in current clinical practice.
Temperature regulation in women: Effects of the menstrual cycle
Published in Temperature, 2020
Fiona C. Baker, Felicia Siboza, Andrea Fuller
The human menstrual cycle, defined as the interval between the first day of bleeding of one cycle and first day of bleeding of the next cycle, typically lasts 25 to 35 days, with an average of 28 days for women in their twenties, and 26 days for women in their forties [37]. The follicular phase has an interval of between 10 and 20 days and the luteal phase of between 9 and 17 days, with greater inter-individual variance for the follicular phase [38]. Consistent with established clinical research, prospective data collected from multiple menstrual cycles in over 120,000 women (~612,000 cycles) using the Natural Cycle app, which included daily basal oral temperature measurement, dates of menstruation, and results of an ovulation prediction kit for some cycles, revealed a mean cycle length of 29.3 days, with a mean follicular phase length of 16.9 days (95%CI: 10 to 30 days) and a mean luteal phase length of 12.4 days (95%CI: 7 to 17 days) [39]. Mean cycle length decreased significantly with age, by 3.2 days from age 25 to 45 years. Also, evident from this “big data” set is the variability in menstrual cycle duration between women and within menstrual cycles of the same woman, mostly as a result of variability in the duration of the follicular phase [39]. Similarly, in a cohort of ~98,000 women (~225,000 cycles), in whom data were collected using a mobile app period tracker (Ovia Fertility) and day of ovulation was confirmed with an ovulation prediction kit, average cycle length was 29.6 days, and average follicular and luteal phase lengths were 15.8 days and 13.7 days, respectively [40].
Related Knowledge Centers
- Estrogen
- Follicular Phase
- Gonadotropin
- Luteinizing Hormone
- Menstrual Cycle
- Menstruation
- Ovulation
- Progesterone
- Endometrium
- Follicle-Stimulating Hormone