Related Experiment Video
Updated: Jul 12, 2026
08:50
Single Cell Collection of Trophoblast Cells in Peri-implantation Stage Human Embryos
Published on: June 12, 2020
Human chorionic gonadatropin (hCG) during third trimester pregnancy
G Edelstam1, C Karlsson, M Westgren
1Department of Obstetrics and Gynaecology, Karolinska University Hospital at Huddinge, Stockholm, Sweden. greta.edelstam@karolinska.se
Scandinavian Journal of Clinical and Laboratory Investigation
|September 1, 2007
Summary
Serum hCG levels significantly decrease 2-3 weeks before spontaneous labor, potentially increasing uterine contractility. This finding offers new insights into the hormonal regulation of childbirth initiation during late pregnancy.
Area of Science:
- Reproductive Endocrinology
- Maternal-Fetal Medicine
Background:
- Established reference values for third-trimester pregnancy blood samples are recent, previously relying on non-pregnant individuals.
- Variations in steroid hormone levels in late pregnancy preceding delivery are not fully understood.
- Investigating preterm hormone levels may reveal factors influencing labor initiation.
Purpose of the Study:
- To investigate hormone level changes in the final weeks of normal pregnancy.
- To explore the role of hormones, particularly hCG, in the initiation of spontaneous labor.
- To identify potential triggers for increased uterine contractility before delivery.
Main Methods:
- Blood samples collected from 135 women at weeks 33, 36, and 39 of pregnancy and postpartum.
- Analysis of serum human chorionic gonadotropin (hCG), oestradiol, and progesterone levels.
- Retrospective data rearrangement to align hormone levels with the week preceding delivery.
Main Results:
- Oestradiol and progesterone levels gradually increased throughout the third trimester.
- Serum hCG levels showed a gradual decrease during the third trimester.
- A significant decrease in hCG was observed 2-3 weeks before spontaneous labor onset (p<0.03).
Conclusions:
- Systematic investigation of third-trimester hormone levels, including hCG, is crucial.
- A significant decline in serum hCG 2-3 weeks pre-labor may reduce its tocolytic effect.
- This hCG decrease could contribute to increased uterine contractility and initiate labor.
More Related Videos
Related Concept Videos
01:27Ovarian Cycle
The menstrual cycle includes a critical component known as the ovarian cycle, which undergoes two main phases each month—the follicular phase and the luteal phase. The follicular phase is variable and averaging around 14 days. Ovulation, triggered by a surge in luteinizing hormone (LH), marks the transition between the two phases. The second phase, the luteal phase, is relatively consistent, lasting approximately 14 days, and is marked by the activity of the corpus luteum. While a cycle length...
01:24Gonadal and Placental Hormones
The gonads, namely the testes in males and the ovaries in females, are pivotal in producing gonadal hormones that orchestrate the intricate processes of sexual development and reproduction.
In males, testosterone is the primary gonadal androgen. It plays a central role in the maturation of male reproductive organs — the penis and testes. Additionally, testosterone is instrumental in the development of secondary sexual characteristics — a deep voice as well as facial and pubic hair growth — and...
In males, testosterone is the primary gonadal androgen. It plays a central role in the maturation of male reproductive organs — the penis and testes. Additionally, testosterone is instrumental in the development of secondary sexual characteristics — a deep voice as well as facial and pubic hair growth — and...
01:22Hormonal Regulation of the Menstrual Cycle
The ovarian cycle regulates endometrial changes throughout a single menstrual cycle via the coordinated action of gonadotrophin-releasing hormone (GnRH) and gonadotrophins.
At puberty, GnRH begins a pulsatile release pattern, which triggers the anterior pituitary gland to secrete follicle-stimulating hormone (FSH) and luteinizing hormone (LH). The frequency and amplitude of GnRH pulses vary across the menstrual cycle, with faster pulses favoring LH release and slower pulses favoring FSH release.
At puberty, GnRH begins a pulsatile release pattern, which triggers the anterior pituitary gland to secrete follicle-stimulating hormone (FSH) and luteinizing hormone (LH). The frequency and amplitude of GnRH pulses vary across the menstrual cycle, with faster pulses favoring LH release and slower pulses favoring FSH release.
01:15Transcytosis of IgG
Transcytosis is the process in which molecules are internalized by endocytosis, transported across the cell, and released through exocytosis from the opposite end of the cell. Molecules such as insulin, immunoglobulins, and certain nutrients are transferred through the recycling endosomes by recycling and transcytosis.
IgG molecules from a mother undergo transcytosis starting around 13 weeks of gestation. The amount of IgG transferred and entering the fetal blood circulation increases with...
IgG molecules from a mother undergo transcytosis starting around 13 weeks of gestation. The amount of IgG transferred and entering the fetal blood circulation increases with...
01:30Hormonal Control of the Ovarian Cycle
The ovarian cycle is meticulously regulated by the hypothalamic-pituitary-gonadal axis. This cycle orchestrates the release of a mature oocyte, essential for reproduction.
Before puberty, the hypothalamus releases GnRH in a low frequency, low amplitude pulsatile manner. This along with the immature hypothalamic-pituitary-gonadal axis activity, results in low estrogen levels and the absence of a fully functional ovarian cycle. At puberty, GnRH secretion increases in both frequency and...
Before puberty, the hypothalamus releases GnRH in a low frequency, low amplitude pulsatile manner. This along with the immature hypothalamic-pituitary-gonadal axis activity, results in low estrogen levels and the absence of a fully functional ovarian cycle. At puberty, GnRH secretion increases in both frequency and...
01:19Secretory Phase
The secretory phase of the menstrual cycle, spanning from day 14 to 28 in a typical 28-day cycle, is a period of significant physiological changes in the female reproductive system. This phase commences immediately after ovulation and is characterized by the preparation of the endometrium for potential embryo implantation.
Following ovulation, the corpus luteum, a temporary endocrine structure, produces progesterone and estrogens. These hormones stimulate the growth and coiling of endometrial...
Following ovulation, the corpus luteum, a temporary endocrine structure, produces progesterone and estrogens. These hormones stimulate the growth and coiling of endometrial...