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Implantation and Embryonic Imaging
Published in Mary C. Peavey, Sarah K. Dotters-Katz, Ultrasound of Mouse Fetal Development and Human Correlates, 2021
Mary C. Peavey, Sarah K. Dotters-Katz
The primordial heart starts to beat at 6 weeks, and rapid fetal growth and organogenesis occurs from weeks 6–10. Transvaginal ultrasonography can detect fetal cardiac activity as early as 34 gestational days, or as early as a CRL length of 1.6 mm. Cardiac activity should be routinely detected when the human embryo has reached 4–5 mm in length. The absence of a heart beat when the CRL is >4 mm confirms a non-viable fetus (12). Findings suspicious for, but not diagnostic of pregnancy failure, CRL of <7 mm and no heartbeat. In humans, the crown rump length at 10 weeks is approximately 30 mm. In humans, the amnion is not visible until at least CRL of 7 mm, or approximately 7 weeks gestational age.
Implantation and In Utero Growth
Published in Arianna D'Angelo, Nazar N. Amso, Ultrasound in Assisted Reproduction and Early Pregnancy, 2020
Kugajeevan Vigneswaran, Ippokratis Sarris
Following on from the appearance of the YS, the next structure that becomes visible within the chorionic sac is the early embryo. Ultrasound can detect the presence of an embryo from 5 to 6 weeks of gestational age, where it is first seen as a linear echogenic structure measuring 2–3 mm lying alongside the YS. From the gestational age of 5 to 9 weeks, there is rapid embryonic development and organogenesis, and the “fetal pole” can be measured along its long axis. The term crown-rump length had been used to denote the size of the embryo at this stage; however, these anatomical structures are not possible to differentiate until 10 weeks of gestation.
Ultrasound in Detection of Growth Retarded Fetuses
Published in Asim Kurjak, John M. Beazley, Fetal Growth Retardation: Diagnosis and Treatment, 2020
Viŝnja Latin, Jadranka Pavletić
The first trimester of pregnancy is the best period for ultrasonically estimating gestational age for at that stage biological variations are minimal and there is the best growth rate of the embryo. Measurement of the crown-rump length, originally described by Robinson, is the most accurate method for determining gestational age,14 i.e., ±4.7 d (2 SD of the mean).15 The CRL measurement which is obtainable by the 8th week of gestation,16 is the longest length of embryo, defined as the distance between the outer edge of the crown to the outer edge of the rump. Limbs and yolk sac are not included (Figure 1).
The predictive value of maternal serum AFP to PAPP-A or b-hCG ratios in spontaneous preterm birth
Published in Journal of Obstetrics and Gynaecology, 2022
Ebru Celik, Rauf Melekoğlu, Arzu Baygül, Uzeyir Kalkan, Yavuz Şimşek
This was a prospective observational study recruiting a low-risk population of pregnant women attending the maternity care unit the Turgut Ozal Medical Center, Inonu University from July 2014 to January 2016 for the first trimester screening test for aneuploidy. Biochemical markers (free β-hCG and PAPP-A) in maternal serum were measured during the first trimester screening test. Blood tests for AFP were also performed to evaluate the association with sPTB. The definite gestational age was determined using crown-rump length measurements. Maternal demographic and clinical characteristics related to pregnancy and birth outcomes were collected from electronic databases. This study was approved by the Inonu University Medical School Ethics Committee (2013/8). Written informed consent was obtained from all the participants.
Screening models combining maternal characteristics and multiple markers for the early prediction of preeclampsia in pregnancy: a nested case–control study
Published in Journal of Obstetrics and Gynaecology, 2022
Li Chen, Yan Pi, Kai Chang, Sifu Luo, Zhuyun Peng, Ming Chen, Lili Yu
This was a nested case–control study drawn from a prospective observational study of adverse pregnancy outcomes that was carried out during the period from June 2014 through December 2016 at the Department of Obstetrics and Gynaecology, Daping Hospital of the Third Military Medical University in Chongqing, China. The study population included 67 pregnancies that subsequently developed PE and had first serum samples collected at 11–13 wks of gestation. For 25 pregnancies that subsequently developed PE at 16–20 wks of gestation, additional serum samples were collected. For 73 pregnancies that subsequently developed PE at 24–28 wks of gestation, a third set of serum samples was collected. For each selected case, one healthy pregnant woman, with no history of any hypertension-related disorder, who had been admitted to the hospital during the same period, was selected as a control and matched by gestational age. Patients were excluded if they had a multiple pregnancy, history of PE during a previous pregnancy, chronic hypertension, pre-gestational or gestational diabetes mellitus, chronic liver disease, or history of renal disease. Gestational age was determined based on the last menstrual period and confirmed by ultrasound measurement of crown-rump length.
Echogenic particles in the amniotic fluid of term low-risk pregnant women: does it have a clinical significance?
Published in Journal of Obstetrics and Gynaecology, 2021
Gul Nihal Buyuk, Z. Asli Oskovi-Kaplan, Serkan Kahyaoglu, Yaprak Engin-Ustun
Term singleton pregnant women (37–42 weeks of gestation) who delivered either vaginally or by caesarean section within 24 h of the ultrasound scan were included in this study. The exclusion criteria were as follows: pregnant women with previous caesarean section or uterine surgery, pregnancies with a non-vertex presentation, pregnancies with indefinite gestational age (absent first-trimester ultrasound or unknown last menstrual period), multiple pregnancies, if delivery was not performed within 24 h of the ultrasound scan, high-risk pregnancies (preeclampsia, intrauterine growth restriction, preterm delivery) and pregnancies complicated by a systemic disease (thrombophilia, hypertension, diabetes, etc.). Clinical characteristics of the patients, amniotic fluid characteristics on ultrasound (anechoic or echogenic), obstetrical results, and the characteristic of the amniotic fluid following the artificial or spontaneous rupture of membranes (clear/vernix/meconium-stained) were recorded. Gestational age was determined due to crown-rump length in the first-trimester ultrasound, if available. In cases when early ultrasound data were not available, gestational age was calculated according to the first day of the last menstrual period. The study group was formed of pregnant women with dense intra-amniotic free-floating particles in a 1–5 mm linear size (Figure 1). Upon inspection of the amniotic fluid following the rupture of membranes, vernix caseosa was considered when white and thick particles were detected. The fluid was considered meconium-stained when greenish, yellow-green, or brown-green particles were present.