The context of birth
Helen Baston in Midwifery, 2020
Each month of the menstrual cycle an egg is released from the ovary into the fallopian tube. Following sexual intercourse, sperm migrate from the vagina, through the cervix into the uterus and swim up the fallopian tubes. When one sperm penetrates the egg, the gametes unite, and the egg is fertilised and becomes a solid ball of rapidly dividing cells (morula) and continues down the fallopian tube into the uterus where it embeds. It is called a blastocyst when it becomes a hollow ball of cells which is one-cell thick, except in one area which is thicker. The cells nearest the lumen of the blastocyst become the embryo and those nearer the outer wall, the trophoblast, become the placenta. The trophoblast further differentiates into an outer membrane known as the chorion, which surrounds the blastocyst, and an inner membrane known as the amnion, which develops into the amniotic sac. The sac begins to fill with amniotic fluid which the developing embryo floats in. The developing placenta starts to produce a hormone called human chorionic gonadotrophin (hCG) which acts on the ovaries preventing further ovulation and stimulating the production of oestrogen and progesterone and maintenance of the corpus luteum. Oestrogen and progesterone are also produced from the developing placenta and levels are adequate by 5–6 weeks, from which time production from the corpus decreases.
Current Concepts of Implantation and Decidualization
Gabor Huszar in The Physiology and Biochemistry of the Uterus in Pregnancy and Labor, 2020
What is a chorionic gonadotropin? Chorionic gonadotropins are placental in origin, elaborated early in pregnancy and luteotropic in nature. The use of such a generic term without more precise biochemical definition seems inappropriate at this time. Hormones of placental origin exist, differing in time of expression, in biochemical structure and immunological reactivity; some with primary types of action and some with secondary types of action, shared, perhaps, by other placental or pituitary hormones. In order to determine if a hormone is of embryonic origin and plays a role in implantation, its temporal expression, its site of origin, its target, the nature of its action, and its biochemistry must be distinguished from existing placental and pituitary peptide hormones.
The placenta and the umbilical cord
Frank J. Dye in Human Life Before Birth, 2019
A portion of the chorion and a portion of the decidua cooperate to form the placenta. The chorion is composed of two parts, and the decidua is composed of three. As already stated, initially, the chorion is uniformly villated; however, as the conceptus grows, much of it loses its villi and is then referred to as the chorion laeve (smooth chorion). The balance of the chorion is the chorion frondosum (bushy chorion). As the conceptus implants into the decidua, three decidual regions are discernible: the decidua parietalis is initially farthest from the conceptus, the decidua capsularis is above the conceptus (between conceptus and uterine cavity), and the decidua basalis is the portion underneath the conceptus.
Extratubal secondary trophoblastic implants (ESTI) following laparoscopic bilateral salpingectomy for ectopic pregnancy: problems that have been neglected for a long time
Published in Gynecological Endocrinology, 2022
Ting Wang, Qin Li
A 26-year-old gravida 3, para 0 woman presented in emergency room with lower abdominal pain and a positive pregnancy test (β-HCG: 3981 mIU/ml) after right salpingectomy for unruptured tubal ectopic pregnancy by laparoscopy in another hospital 6 weeks ago. Physical examination was normal and transvaginal ultrasound revealed a normal empty uterus with 4 mm endometrium, normal ovaries and there was no evidence of pregnancy in utero and extrauterine. The surgical records of the outside hospital showed that the right fallopian tube was not broken, and it was excised and taken out completely. Histology confirmed chorionic villi in the fallopian tube. Serial β-HCG levels were 4902, 4604 and 4036 on days 1, 4 and 7 of hospitalization, respectively. In addition, MRI showed no abnormalities in abdominal organs and peritoneum. Lung CT displayed normal. The special past history (PH) was that the patient underwent laparoscopic left salpingectomy for ectopic pregnancy 4 years ago.
Laparoscopic temporary bilateral uterine artery occlusion – a successful pregnancy outcome of heterotopic intrauterine and cervical pregnancy
Published in Journal of Obstetrics and Gynaecology, 2021
Lanying Jin, Limei Ji, Mingjun Shao, Min Hu
A definite diagnosis could not be made at the time of admission. The β-human chorionic gonadotropin (HCG) was 200,000 IU/L and the haemoglobin was 9.0 g/dL on admission. A biopsy was immediately taken from the cervical mass. A local haemorrhage was spewing when a cervical mass biopsy was performed, with a blood loss of more than 1000 mL. Two additional units of packed red blood cells were given immediately. A repeated vaginal gauze packing failed three times, and when we finally placed 12 pieces of gauze, the bleeding stopped with the hand compression for half an hour. A histopathological examination revealed there were chorionic villi. A magnetic resonance image (MRI) was obtained which confirmed the presence of a cervical ectopic pregnancy in addition to a viable intrauterine pregnancy.
A diagnostic profile on the PartoSure test
Published in Expert Review of Molecular Diagnostics, 2020
Safoura Rouholamin, Maryam Razavi, Mahroo Rezaeinejad, Mahdi Sepidarkish
Fetal fibronectin is a glycoprotein protein produced by fetal cells. It is found in placental tissue, amniotic fluid, and at the interface of the chorion and the decidua (between the fetal sac and the uterine lining). This fibronectin protein acts as an adhesive or ‘biological glue’ and binds the fetal sac to the uterine lining. Fetal fibronectin released into cervicovaginal fluid if the connection is disrupted. So the positive test for fFN (>50 ng/ml) between week 22 and week 34 of pregnancy can be a sign that the PTB is imminent [24]. Vaginal bleeding interferes with test results and bloody samples may lead to false-positive results. It is recommended that the sample be collected following the cessation of active vaginal bleeding [25]. A comprehensive systematic review by Faron et al. in 2018 reported that none of the summary estimates was over 10 for LR+ and lower than 0.1 for LR-. The authors conclude that the fFN test should not be used as a screening test for asymptomatic women. Also, the test application is not valid for asymptomatic women at high risk and could not be used in practice especially for women with multiple pregnancies [26].