Embryonic heart rate as a prognostic factor for chromosomal abnormalities

Clinical and Ultrasound Evaluation of Early Threatened Miscarriage to Predict Pregnancy Continuation up to 28 Weeks: A Prospective Cohort Study

OBJECTIVES

(1) To study the predictors of pregnancy continuation up to 28 weeks in first-trimester threatened miscarriage after a single clinical and ultrasound (US) evaluation. (2) To assess the role of both clinical and US predictors in counseling and decreasing repeated emergency follow-up scans.

METHODS

A prospective observational study that included a cohort of 241 patients with threatened miscarriage (≥6-12 weeks) was conducted. They had a single clinical and US evaluation, and then they were contacted by weekly phone calls until completing 28 weeks' gestation or reporting miscarriage. Independently, all patients were followed by the recommended routine US scanning with or without emergency visits.

RESULTS

Two hundred thirty-three patients completed the study, of whom 193 patients continued up to 28 weeks' gestation, and 40 miscarried (17.1%). Only spotting/mild bleeding episodes and progesterone treatment were the clinical predictors of fetal viability. The embryonic/fetal heart rate (E/FHR) was the best single US predictor, with a specificity and positive predictive value of 95.3% and 97.2%, respectively. Combining 3 US parameters, at their best cutoff points (E/FHR >113 beats per minute, crown-rump length >19.9 mm, and gestational sac diameter >27.3 mm), had a specificity and positive predictive value of 98% and 99% (first-trimester US triad of fetal viability).

CONCLUSIONS

[1] In first-trimester threatened miscarriage, clinical parameters that could predict fetal viability included spotting/ mild bleeding and progesterone treatment. [2] After a single US scan, the presence of at least an E/FHR of greater than 113 bpm or the suggested first-trimester US triad appeared as a simple, measurable, and effective predictor of pregnancy continuation up to 28 weeks. [3] These US predictors are not to replace the recommended scheduled scanning during pregnancy. [4] This can improve patients' counseling and decrease the need for repeated emergency follow-up scans. Otherwise, there is an indication for repeating US scans at a 1-week to 10-day interval.

Reference values for fetal heart rate in cattle in the first trimester of pregnancy

The aim of this study was to create a fetal heart rate (FHR) reference curve for singleton bovine fetuses in the first trimester of gestation and to determine its possible relationship with the outcome of pregnancy. Forty-eight Holstein-Friesian cows with one fetus and five cows with twins were used. Fetal heart beatings were recorded on videotape during transrectal scanning with a 5 and/or 7.5 MHz linear array transducer on a weekly basis between Days 40 and 95 of gestation. FHR was calculated by averaging the results of five counts of the same record by the same observer. For singleton pregnancies, a reference curve was created using the mean, the standard deviation (SD) and the 5th and 95th percentiles. The FHR increased from Days 40-46 (173 beats/min) to Days 61-67 (183 beats/min). After a peak, the FHR decreased slowly until Days 89-95 (175 beats/min), while the SD increased. There was no significant difference between singleton and twin fetuses. in the aborted and lost fetuses in twin gestation due to fetal reduction, both bradycardia and tachycardia were detected compared to the singleton pregnancy reference curve.

Reference intervals of embryos/fetuses heart rate between 6 and 14 weeks of pregnancy

OBJECTIVE

To determine reference intervals for the embryos/fetuses heart rate (HR) between 6 and 14 weeks of pregnancy.

METHODS

A retrospective cross-sectional study was carried in a single center with singleton pregnancies of embryos/fetuses with a crown-rump length (CRL) between 5 and 85 mm. The HR was assessed by real time M-mode or spectrum Doppler ultrasound. To evaluate the correlation between embryo/fetal HR and CRL, polynomial equations were calculated, with adjustment by the determination coefficient (R(2)).

RESULTS

A total of 5867 pregnancies were assessed. The mean gestational age was 10.37 ± 2.12 weeks. The mean maternal age was 26.41 ± 6.78 years. The mean embryo/fetal HR (bpm) for the CRL (mm) intervals 5├15; 15├25; 25├35; 35├45; 45├55; 55├65; 65├75; 75├85 was 145.1 ± 18.7; 167.2 ± 10.1; 166.9 ± 8.7; 165.5 ± 6.9; 162.2 ± 6.8; 159.2 ± 6.4; 157.1 ± 6.4; 154.9 ± 7.3; respectively. The following third-order equation best represented the correlation between embryo/fetal HR and CRL: HR = 119.25 + 3.596*CRL-0.07954*CRL(2 )+ 0.00051*CRL(3) (R(2 )= 0.36).

CONCLUSION

Reference intervals of HR in embryos/fetuses in a large sample were determined. These reference intervals can be used in high-risk early pregnancy losses.

Outcome of early first-trimester pregnancies (< 6.1 weeks) with slow embryonic heart rate

OBJECTIVE

The purpose of this article is to assess prospectively the value of concordant versus discordant gestational age (GA) calculations in predicting subsequent embryonic demise in embryos with a slow heart rate, as determined on early first-trimester ultrasound.

SUBJECTS AND METHODS

Thirty-six consecutive singleton pregnancies with slow embryonic heart rate (< 100 beats/min) measured on a 5.0- to 6.1-week ultrasound were prospectively identified. Pregnancies were defined as "discordant" if there was more than 5 days' difference between GA determined by biometrics compared with GA determined by last menstrual period and were defined as "concordant" if there was less than 5 days' difference between the GA measurements.

RESULTS

Of the 36 embryos with heart rate less than 100 beats/min at 5.0-6.1 weeks' GA, 16 went on to demise and 20 survived. Of the 16 that went on to demise, 14 were discordant (88%) and two were concordant (12%). Of the 20 that survived, 16 were concordant (80%) and four were discordant (20%). The proportion of discordant pregnancies that went on to demise was 14 of 18 (negative predictive value, 78%). The proportion of concordant pregnancies that went on to survival was 16 of 18 (positive predictive value, 89%). The rate of demise in the discordant group was significantly higher than that in the concordant group (p < 0.001, Fisher's exact test).

CONCLUSION

Embryonic heart rate less than 100 beats/min detected at 6.1 weeks or less is not necessarily a poor prognostic indicator. The likelihood of subsequent first-trimester survival is significantly higher if there is concordance between GA as calculated by biometrics and last menstrual period than if there is discordance.