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About Recent Edits Go ad-free. Edit article. View revision history Report problem with Article. Citation, DOI and article data. Gaillard, F. Gestational sac.
Reference article, Radiopaedia. URL of Article. A true gestational sac can be distinguished from a pseudogestational sac by noting: its normal eccentric location: it is embedded in endometrium, rather than centrally within the uterine cavity presence of the double decidual sign most helpful at 4.
See also empty gestational sac eccentric gestational sac small gestational sac. In this cross sectional study a cubic association between HR and gestational age was found.
However those pregnancies were followed through 13 weeks of gestation, when a natural slowing in HR is observed. We described a linear relationship through 10 weeks of gestation with an excellent R 2 value. Given the rather important variation in BPM per second, a slower HR is not a reliable tool to predict the occurrence of a pregnancy loss unless it is below BPM at a gestational age greater than 6 weeks of gestation In our study, a HR slower than in continuing pregnancies was predictive of a subsequent pregnancy loss only between 7 and 8 weeks of gestation, but not prior, or after, this time.
Even if highly specific of pregnancy loss when absent, HR abnormalities presented very close to the event, thus providing little time for counseling. A major strength of our study is the advantage of a single investigator performing all the ultrasounds, thus maintaining consistency in the measurements, with small inter-observer variability.
Additionally, all subjects included in the study had precisely known gestational ages further strengthening the accuracy of our results. Limitations of the study include the relatively small sample size, along with a patient population treated for infertility, which may make our results not generalizable to spontaneous conceptions.
Additionally, some pregnancies were already lost at the time of the first ultrasound at 5 or 6 weeks of gestation, and we were not able calculate the interval between the measured abnormal parameter and the loss. In fact, our model was suitable mostly for pregnancies that had an ultrasound at 6 weeks and were lost at 8—9 weeks of gestation, or later.
In conclusion, we were able to establish a statistical model using only early pregnancy ultrasound markers to predict a first trimester loss. GS and YS were the earliest parameters that could reliably be used as prognostic factors for pregnancy loss, as they became abnormal as early as 6 weeks of gestation with high sensitivity and specificity.
Of all the evaluated parameters, the YS was the strongest single predictor. These findings are clinically useful for patient counseling and determining the need for closer monitoring. In fact, if these parameters are normal at 6 weeks, the pregnancy will likely continue beyond the first trimester.
Although needing prospective validation, our results support changing the current standard of care of performing the first obstetric ultrasound at 9 weeks of gestation to 6 weeks of gestation.
If the YS and the GS are normal, a provider can offer reassurance concerning the decreased likelihood of a pregnancy loss. American College of Obstetricians and Gynecologists. Early pregnancy loss. Practice Bulletin No. Orvieto, R. J Assist Reprod Genet 17 , — Wang, X. Conception, early pregnancy loss, and time to clinical pregnancy: a population-based prospective study. Fertil Steril 79 , —84 Article Google Scholar. Zinaman, M. Estimates of human fertility and pregnancy loss. Fertil Steril 65 , —9 Lathi, R.
Tissue sampling technique affects accuracy of karyotype from missed abortions. J Assist Reprod Genet 19 , — Zhang, H. Analysis of fetal chromosomal karyotype and etiology in cases of early spontaneous abortion. Google Scholar. Lek, S. BMC Pregnancy Childbirth 17 , 78—84 Tarasconi, B. Fertil Steril , — Pexsters, A. Ultrasound Obstet Gynecol 38 , —5 Yi, Y. A logistic model to predict early pregnancy loss following in vitro fertilization based on infertility patients. Reprod Biol Endocrinol 14 , 15 Khalil, A.
Maternal age and adverse pregnancy outcome: a cohort study. Ultrasound Obstet Gynecol 42 , —43 Datta, M. Efficacy of first-trimester ultrasound parameters for prediction of early spontaneous abortion. Int J Gynaecol Obstet , — Pillai, R. Prediction of miscarriage in women with viable intrauterine pregnancy—A systematic review and diagnostic accuracy meta-analysis. Stamatopoulos, N. Prediction of subsequent pregnancy loss risk in women who present with a viable pregnancy at the first early pregnancy scan.
Tan, S. Abnormal sonographic appearances of the yolk sac: which can be associated with adverse perinatal outcome? Med Ultrason 16 , 15—20 Ashoush, S. Relation between types of yolk sac abnormalities and early embryonic morphology in first-trimester missed pregnancy loss.
J Obstet Gynaecol Res. Detti, L. Pilot study establishing a nomogram of yolk sac growth during the first trimester of pregnancy. Definitions of infertility and recurrent pregnancy loss: a committee opinion. Fertil Steril , 99 , 63 Goodman, N. American association of clinical endocrinologists, American college of endocrinology, and Androgen Excess and PCOS Society disease state clinical review: Guide to the best practices in the evaluation and treatment of polycystic ovary syndrome - Part 2.
Endocr Pract 21 , —26 Papaioannou, G. Normal ranges of embryonic length, embryonic heart rate, gestational sac diameter and yolk sac diameter at weeks. Fetal Diagn Ther 28 , —19 Goldstein, S. Correlation between karyotype and ultrasound findings in patients with failed early pregnancy. Ultrasound Obstet Gynecol 8 , 14— Yoneda, S. J Ultrasound Med 37 , —41 Papageorghiou, A.
International standards for early fetal size and pregnancy dating based on ultrasound measurement of crown-rump length in the first trimester of pregnancy. Ultrasound Obstet Gynecol 44 , —8 Doubilet, P. Long-term prognosis of pregnancies complicated by slow embryonic heart rates in the early first trimester.
J Ultrasound Med 18 , —41 Download references. You can also search for this author in PubMed Google Scholar. Research idea, Figures, Tables, Manuscript writing. Research conduct, Manuscript writing.. Statistical analysis, Tables, Manuscript writing. Statistical analysis. Research conduct, Manuscript writing. Correspondence to Laura Detti. The original online version of this Article was revised: The original version of this Article contained an error in the spelling of the author Patricia J.
Goedecke which was incorrectly given as Patricia J. Reprints and Permissions. Early pregnancy ultrasound measurements and prediction of first trimester pregnancy loss: A logistic model. Sci Rep 10, Absence of fetal heart motion at this stage is consistent with a missed abortion. By TAS, fetal heart motion is usually seen at a diameter of 25 mm. Again, diagnosis of missed abortion via TAS may be unreliable in the presence of maternal obesity, leiomyomas, or retroversion.
Many patients expect that TVS will be performed. Both they and their physicians may be uncomfortable if the diagnosis of early pregnancy loss is not confirmed by this technique. In addition a full bladder is not required for TVS. The majority of patients are more comfortable being scanned transvaginally with an empty bladder. Furthermore, anesthesiologists prefer that patients do not have full stomachs from drinking large volumes of fluid. A new standard in the United States was reached at a multispecialty conference sponsored by the Society of Radiologists in Ultrasound.
It was summarized and published in the New England Journal in by Doubilet et al. The older guidelines 1, 2, and 3 above are now considered suspicious but not diagnostic for a missed abortion. Statistical analysis by Jeve et al. TVS can be used to evaluate women thought to have completed abortions. In a study by Rulin and co-workers, 48 of 49 women determined as having an empty uterus using TVS were spared dilatation and curettage.
Cowett et al. Suspected endometritis or subinvolution of the placental site may require antibiotic or cytotec. Rarely patients will have persistent benign trophoblast.
On Doppler these patients will have extension deep into the myometrium. Two examples are given in Figures 11A and 11B. Fig 11A and B Persistent benign trophoblast is likely in both of these cases.
Both patients had presented with bleeding at 7—8 weeks with intrauterine pregnancy sacs and missed abortion was confirmed. Both were treated with cytotec. We recommend transvaginal scan be performed 1 week after cytotec to document completed abortion or sooner if there is excessive bleeding. The gestational sacs are no longer seen in these two examples. However, areas of markedly increased color Doppler are noted in the myometrium fundally. Management of these cases varies between practitioners and institutions.
Careful D and C under ultrasound guidance gives a histologic diagnosis. This can be seen even when benign trophoblast is found on pathology. Alternatively, the patient may be treated initially with methotrexate. This requires that the pretreatment ultrasound shows no evidence of molar tissue or marked hydropic change. The practitioner must not forget that it is quite common for a patient to pass a decidual cast and falsely think they have a spontaneous abortion of an intrauterine pregnancy, when they actually have an ectopic pregnancy.
For the practitioner to be satisfied with an ultrasound diagnosis of completed abortion, one of three conditions must be met:. A previous ultrasound documented an intrauterine pregnancy, and the endometrial cavity is now empty. Products of conception have been identified pathologically, and the uterine cavity appears empty. Quantitative titers are heading toward zero at an appropriate rate, and the uterine cavity appears empty.
This may also be consistent with a nonviable ectopic or tubal abortion. Both sonologist and practitioner must also entertain the possibility of a heterotopic pregnancy, which is a simultaneous intrauterine and extrauterine twin pregnancy. Particularly with the rise of patients undergoing assisted reproduction, this entity is being encountered more frequently.
Any patient with a history of ectopic pregnancy, tubal ligation or tubal surgery, or pelvic inflammatory disease should undergo TVS by 6 weeks from the last menstrual period LMP.
For patients who are not at high risk for ectopic pregnancy, the two most common presenting symptoms are bleeding and pelvic pain. The pain is typically lateralized over the adnexa. Recent papers by Condous et al. In addition, the clinician should be aware that very small ectopic pregnancies identified on ultrasound may be difficult to identify laparoscopically.
The American Society of Reproductive Medicine guidelines for the medical treatment of ectopic pregnancy were most recently modified in Fig 13 Ampullary tubal ectopic. Fig 14 Ovarian ectopic. Fig 15A Concurrent cervical ectopic and intrauterine pregnancy. Fig 15B Three-dimensional image of a 10 week cervical pregnancy. Fig 16A Interstitial ectopic. Three-dimensional is very useful in distinguishing angular pregnancies from interstitial ectopic pregnancies.
Repeat studies are sometimes required at 7—10 day intervals to differentiate the two. The gestational sac will start filling the endometrial cavity for angular implantations. The IUD was removed. Patient had a normal term pregnancy. Fig 17 A cesarean section scar pregnancy. These cases are typically managed at our institution with intra sac methotrexate followed by standard IM dose of methotrexate. Although the pros and cons of the medical management of ectopic pregnancy with methotrexate are beyond the scope of this chapter, two points are worth making.
Failure to check serial titers can result in improper administration of methotrexate to patients with healthy pregnancies. Litigation has occurred in cases where methotrexate was inadvertently given to patients subsequently found to have an early intrauterine pregnancy. A recent, well-referenced editorial by Gardosi discusses the inaccuracy of LMP dating and advocates routine ultrasound confirmation of dates. Robinson and Fleming published the first crown—rump length tables.
More recent studies with timed ovulation have shown that their table underestimated gestational age by about 1 week Table 3. Crown—rump lengths at gestational ages greater than 10 weeks are less accurate. A review article by Napalitano from summarizes and reviews the multiple articles published on crown—rump dating.
Fig 18 A 9 week CRL. Please note the fetus may start to curl and may be undermeasured. The amnion is now well seen. Obstet Gynecol , The determination of chorionicity of multiple gestations is of obvious interest to the obstetrician because of the greatly increased morbidity and mortality in monochorionic pregnancies and in particular monoamniotic—monochorionic twin pregnancies.
In a well-illustrated study, Monteagudo and co-workers demonstrated the extreme reliability of first-trimester ultrasound in predicting chorionic and amniotic type Figs. Fig 19A and B Two diamniotic monochorionic pregnancies.
The amnions may not be well seen until 8—9 weeks. Fig 20A 6-week dichorionic pregnancy. Two separate gestational sacs clearly seen. Fig 20B 7-week dichorionic pregnancy. Two separate gestational sac sacs clearly seen. Fig 20C 9-week dichorionic pregnancy. The delta sign clearly identifies a dichorionic pregnancy. Fig 20D A demised second twin is displayed. Fig 20E A ipsilon sign in a triplet pregnancy. From the mid s until the present nuchal screening has been combined in various paradigms with biochemical markers to screen for fetal trisomy.
The nuchal measurement is enlarged. No nasal bone was identified. Fig 21B A septated hygroma is noted on an axial view of the neck. CVS revealed trisomy In our lab nuchal measurements greater than 3. If the genetics is normal, the patient is referred for early anatomic survey including pediatric fetal echo. Fig 22 A fetus confirmed trisomy Nuchal screening revealed a nuchal measurement of 3. Micrognathia noted. The early anatomic survey at 11—14 weeks well reviewed in by Souka and Nicolaides.
However, a review by Rossi and Prefumo in of 19 studies found that the sensitivity for the detection of major anomalies was less than ideal compared to the later anatomic surveys. This included acrania, alobar holoprosencephaly, gastroschisis, megacystis, and body stalk anomalies. Screening for congenital anomalies at this gestational age requires additional training. Fig 24 A fetus with acrania at 13 weeks. Fig 25A and B Two fetuses with omphalocoeles at 13 weeks.
Invasive testing is recommended in these fetuses to exclude trisomy Fig 27 A fetus with acrania and pericardial effusion. Major uterine anomalies are not infrequently diagnosed during the first-trimester ultrasound examination. The bicornuate uterus is characterized by its widened transverse diameter and a notched fundus. The septated uterus has a normal uterine contour but a septated endometrial cavity. Three-dimensional imaging has markedly simplified the detection and classification of suspect uterine anomalies.
Fig 29A Three-dimensional image. Didelphus uterus.
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