Fetal loss in the first trimester after demonstration of cardiac activity: relation of cytogenetic and ultrasound findings

Chromosomal Aneuploidy Associated With Clinical Characteristics of Pregnancy Loss

Objective

Embryonic aneuploidy is found in about half of sporadic pregnancy losses and the associations between the chromosomal aneuploidy and clinical characteristics of pregnancy loss remain unclear. The aims of this study were to evaluate the associations between chromosomal aneuploidy of products of conception (POC) and clinical features of pregnancy loss.

Methods

We conducted a retrospective cohort study including 1,102 women experienced singleton pregnancy loss and underwent chromosomal microarray analysis (CMA) detection of POC in our hospital. The results of molecular karyotypes and clinical features including maternal age, history of pregnancy loss, gestational age, vaginal bleeding and ultrasonographic findings were extracted from the medical records. χ² test was used to compare categorical data between groups.

Results

631 (57.26%) POC specimens were detected to be chromosomal aneuploidy. Aneuploid rates were significantly higher in women >35 years (P < 0.001) and pregnancy loss <11 gestational weeks (P = 0.044), but the rates of sex chromosome abnormalities and triploid were significantly higher in women ≤35 years (P < 0.001, P = 0.002) and the rates of viable autosomal trisomy and sex chromosome abnormalities were significantly high in those women with pregnancy loss ≥11 weeks (P < 0.001, P < 0.001). Aneuploid rate was overall similar between the sporadic and the recurrent pregnancy loss (RPL) (P = 0.404), but the rate of sex chromosome abnormalities was higher in women with sporadic pregnancy loss (P = 0.03). Aneuploid rates were higher in subjects with yolk sac or embryo than in those without (P < 0.001 and P = 0.001).

Conclusion

Advanced maternal age is mainly associated with autosomal trisomy, while sex chromosome abnormalities and triploid might be more likely to occur in younger women. Aneuploidy rates might be no association with previous pregnancy loss except for sex chromosome abnormalities. Pregnancy loss without yolk sac or embryo might be less related to embryonic aneuploidy, and other factors should be emphasized.

Impact of location on placentation in live tubal and cesarean scar ectopic pregnancies

INTRODUCTION

The objective of this study was to evaluate the impact of implantation outside the normal intra-uterine endometrium on development of the gestational sac.

METHODS

We reviewed and compared the ultrasound measurements and vascularity score around the gestational sac in 69 women diagnosed with a live tubal ectopic pregnancy (TEP) and 54 with a cesarean scar ectopic pregnancy (CSP) at 6-11 weeks of gestation who were certain of their last menstrual period.

RESULTS

The rate of a fetus with a cardiac activity in the study population was significantly (P < 0.001) higher in CSPs than in TEPs. The median maternal age, gravidity and parity were significantly (P =.005; P < 0.001 and P < 0.001, respectively) lower in the TEP than in the CSP group. The number of gestational sac size <5th centile for gestational age was significantly (P < 0.001) higher in the TEP than in the CSP group. There were no differences between the groups for the other ultrasound measurements. In cases matched for gestational age, the gestational sac size was significantly (P < 0.001) smaller in the TEP compared to the CSP group. There was a significant (P < 0.001) difference in the distribution of blood flow score with CSP presenting with higher incidence of moderate and high vascularity than TEP.

DISCUSSION

Both TEP and CSP are associated with a higher rate of miscarriage than intrauterine pregnancies and the slow development of the gestation sac is more pronounced in TEPs probably as a consequence of a limited access to decidual gland secretions.

Two-year outcome after recurrent first trimester miscarriages: prognostic value of the past obstetric history

PURPOSE

Recurrent miscarriage (RM) is a stressful condition which gives rise to extensive diagnostic evaluation and is seen as a potentially curable maternal disease. Nevertheless, epidemiological data have shown that outcome is related to fertility. In addition to maternal age and number of preceding miscarriages, further markers derived from the past history may support counselling.

METHODS

Observational trial comprising 228 couples who were referred between 1996 and 2003 for immunological evaluation at maternal ages 20-39 years after three or more spontaneously conceived primary first trimester miscarriages. They were interviewed in 2005, ongoing pregnancies were followed up until birth in 2006. Past obstetric history was correlated with 2 year cumulative pregnancy and delivery rates (CPR, CDR).

RESULTS

CPR and CDR were 206/228 (90.4 %) and 174/228 (76.4 %). Duration of infertility was associated with lower CPR (up to 3/>3 years, p < 0.01), whereas age and number of preceding losses inversely correlated with CDR (<35 years/35-39 years, p < 0.002; 3/>3 miscarriages, p < 0.002). Detection of an embryonic heart beat in 2-3 of the first three miscarriages resulted in favourable outcome (CPR: p < 0.02, CDR: p < 0.002). Prognosis was excellent in younger fertile women after three miscarriages where vital signs had been detected; under less favourable conditions not only risks for further miscarriage, but also for secondary infertility were elevated.

CONCLUSION

Secondary infertility is a feature of RM. Embryonic vital signs in preceding pregnancies are prognostic markers and should be regarded as a strong confounding factor in trials on therapeutic interventions. Prevention may be more appropriate than treatment.

1(st) trimester miscarriage: four decades of study

Miscarriage is a very common occurrence in humans. This paper sets out to present published data on research that has provided increased understanding of pregnancy failure. Clarification of definitions, exploring the range of failures from preclinical to later pregnancy losses, and the scientific tools employed to find information on the losses have been documented. What is now understood, which tools work best, and the associated limitations are all discussed. Early studies used cytogenetic methods and tissue culture to obtain results. Improvements in laboratory tools such as better tissue culture incubators, inverted microscopes, laminar flow hoods, improvements in culture media, all contributed to obtaining more results for patients. These studies demonstrated the significant contribution of unbalanced chromosomal karyotypes to pregnancy failure. Maternal age as a contributing factor in trisomy was clearly demonstrated. First trimester miscarriage exhibits very high cytogenetic abnormality; in contrast to very low rates in later losses. Combining data across all time periods of pregnancy will affect the significance of chromosomal error in the early pregnancy failures. Cytogenetic methods investigate whole genomes, and are considered to represent the standard against which new methods must be validated. New molecular genetic methods provide the opportunity to examine samples without the necessity of tissue culture. Techniques may be site-specific or whole genome. Fluorescent in situ hybridisation (FISH), comparative genomic hybridisation (CGH), array-based CGH, single nucleotide polymorphism (SNP) detection, quantitative polymerase chain reaction (qPCR), and quantitative fluorescent PCR (QF-PCR), have all been utilised. In comparison studies with classical/conventional cytogenetics, each newer method offers advantages and limitations. At the present time, a combined approach using conventional and molecular methods will elucidate the cause of miscarriage for almost all samples. In a clinical setting this would be optimum.

Can a smaller than expected crown-rump length reliably predict the occurrence of subsequent miscarriage in a viable first trimester pregnancy?

AIM

To elicit the diagnostic value of smaller than expected crown-rump length (CRL) to predict the occurrence of subsequent miscarriage in women with a viable first trimester pregnancy.

METHODS

A cohort study was conducted in the fetal special care unit of a tertiary care maternity hospital. The recruited participants were young pregnant women at 6-13 weeks of gestation. Transvaginal ultrasonography was performed to determine pregnancy viability and measure the embryonic CRL. To compare the differences in CRL between those pregnancies that remained viable and those that subsequently miscarried, the deviation of observed and expected CRL was calculated and expressed in standard deviations (SD) as Z score. The primary outcome measure was the percentage of pregnancies with antecedent growth delay that miscarried by the end of the first trimester.

RESULTS

Of the pregnancies that subsequently miscarried, 79.3% (42/53) had smaller than expected CRL, and in 56.6% (30/53) the CRL was 2 SD or less from that expected for gestational age (GA). The mean Z score for CRL was significantly lower in pregnancies that subsequently miscarried compared to pregnancies that remained viable (-2.9 ± 2.6 vs -0.8 ± 2.1, respectively, P < 0.001). A CRL of 2 SD or less from that expected for GA as a cut-off point had a sensitivity of 56.6, specificity of 81.9, positive predictive value of 36.6, negative predictive value of 91.1, likelihood ratio positive of 3.1 and likelihood ratio negative of 0.5 in predicting subsequent miscarriage.

CONCLUSION

Viable first trimester pregnancies with small for GA CRL were associated with a higher probability of a subsequent miscarriage.

Association between different morphological types and abnormal karyotypes in early pregnancy loss

OBJECTIVES

To identify the abnormal transvaginal ultrasound (TVS) findings typical of aneuploidic pregnancies that end with early pregnancy loss (EPL).

METHODS

This was a prospective clinical trial over a 2½-year period from January 2004 to June 2006 at the University Hospital of Cagliari, Italy. One hundred and fifty-six singleton pregnancies with EPL were evaluated by TVS, both before and at the moment of EPL diagnosis. Fetal karyotyping was performed on products of conception using microsatellite analysis to exclude maternal contamination in 46,XX cases. The proportions of abnormal karyotypes were compared among different groups of EPLs characterized by different morphological features.

RESULTS

Six morphological types were identified in EPLs, one normal and five abnormal (small gestational sac, small embryo/fetus, early symmetrical arrested growth, enlarged yolk sac and empty sac). The highest rate of chromosomal abnormalities was observed in the early symmetrical arrested growth group (100%), followed by small embryo/fetus (94.1%), enlarged yolk sac (93.3%) and empty sac (72.2%) groups. The majority of cases of trisomy 22 (92.3%) were in the enlarged yolk sac group and the majority of cases with a 45,X karyotype were in the small embryo/fetus group (77.8%).

CONCLUSIONS

There is an association in EPLs between some abnormal karyotypes and some morphological types. The demonstration by TVS of abnormalities in the development of early pregnancy structures could be helpful for predicting aneuploidy in EPLs.

Ultrasonographic findings in spontaneous miscarriage: relation to euploidy and aneuploidy

OBJECTIVE

To evaluate a possible correlation between transvaginal ultrasound findings in miscarriages and cytogenetic analyses from chorionic villi obtained by dilatation and curettage.

DESIGN

Prospective, population-based study.

SETTING

University-based hospital.

PATIENT(S)

Five hundred seventy-six women with spontaneous miscarriage diagnosed between 6 and 12 completed pregnancy weeks.

INTERVENTION(S)

Transvaginal ultrasonography and dilatation and curettage.

MAIN OUTCOME MEASURE(S)

Cytogenetic analyses and ultrasound measurement of embryonic pole.

RESULT(S)

The mean gestational age was 9.5 weeks. Chromosomal analyses were successful in 259 cases, 159 with cytogenetic abnormalities and 100 euploidy. Empty gestational sacs were equally often found in euploidy and aneuploidy, whereas small embryonic or fetal poles were significantly more often associated with aneuploidy.

CONCLUSION(S)

A smaller than expected fetal size when a miscarriage is diagnosed during the first trimester is significantly associated with a chromosomal aberration.

Dating and growth in the first trimester

Measurement of embryonic or foetal size using the greatest length of the embryo or foetal crown rump length can be used to accurately determine the gestational age of a normal first trimester pregnancy to within three to five days. Transvaginal ultrasound scan can be used to measure the size of an embryo and gestation sac earlier than transabdominal ultrasound. The original Robinson curve used for dating pregnancies is still valid in most cases. Ultrasound dating in the first trimester is now recommended for all women with spontaneous pregnancies, even those with certain menstrual dates. First trimester growth in normal pregnancy is not uniform and is influenced by both maternal and foetal factors. Early foetal growth restriction is demonstrated in many pregnancies that subsequently end in first trimester miscarriage and is also demonstrated in fetuses with triploidy, trisomy 18 and possibly trisomy 13. Pregnancies which are small at the 11-14 week ultrasound scan appear to be at risk of later intrauterine growth restriction, preeclampsia and preterm delivery. Cross-sectional and serial measurement of foetal growth in the first trimester may be helpful in predicting both miscarriage and adverse late pregnancy outcomes.

Evidence of early first-trimester growth restriction in pregnancies that subsequently end in miscarriage

OBJECTIVES

To examine whether viable early pregnancies that subsequently end in miscarriage exhibit evidence of first-trimester growth restriction.

DESIGN

Prospective cohort study.

SETTING

Early pregnancy unit (EPU) of a teaching hospital.

POPULATION

Women attending EPU between 5 and 10 weeks of gestation.

METHODS

Women with spontaneously conceived intrauterine, viable singleton pregnancies with certain last menstrual period and regular cycles were included. The deviation between the observed and expected crown-rump length (CRL) for gestation was calculated and expressed as a z score. Pregnancies were followed up until the 11-14 week scan, and the deviation between those that remained viable and miscarried subsequently was calculated.

MAIN OUTCOME MEASURES

Viability at 11-14 week scan.

RESULTS

Over 6 months, 316 women met the inclusion criteria. Twenty-four (7.4%) women were excluded. Of the remaining 292, the pregnancy remained viable in 251 (86%) and 41 (14%) suffered a miscarriage. At the first transvaginal ultrasound, the z score of the mean measured CRL for pregnancies that remained viable was -0.82, SD 1.46, while in pregnancies that subsequently miscarried the z score was -2.42 and the CRL was significantly smaller, SD 1.31 (P < 0.0001). In the latter group, the initial CRL was below the expected mean for gestational age in all women, while in 61% (25/41), the CRL was at least 2 SDs below the expected mean.

CONCLUSIONS

CRL was significantly smaller in pregnancies that subsequently ended in miscarriage. This suggests that early first-trimester growth restriction is associated with subsequent intrauterine death.

Cytogenetic testing of anembryonic pregnancies compared to embryonic missed abortions

PURPOSE

The objective of this study is to determine the rate of abnormalities detected by cytogenetic testing of first trimester miscarriages, in patients with and without an embryonic pole seen on ultrasound.

MATERIALS AND METHODS

A retrospective study of 272 D&Cs for missed abortions in an academic infertility practice from 1999 to 2006. Karyotype results were compared with transvaginal ultrasound findings. Chi-squared analysis was used with a P < 0.05 for significance.

RESULTS

There was a high rate of abnormal karyotypes in all miscarriages (65%). Rates of abnormal karyotypes were 58% and 68% in cases with anembryonic gestations and those with a fetal pole seen, respectively (P > 0.05).

CONCLUSION

The high rate of abnormalities detected in both groups suggests that useful results can be obtained from chromosomal testing of the POC regardless of ultrasound findings. Further studies on the prognostic value and cost effectiveness of chromosomal testing are needed.

Embryo loss pattern is predominant in miscarriages with normal chromosome karyotype among women with repeated miscarriage

OBJECTIVE

The aim of this study was to assess pregnancy loss patterns in women with repeated miscarriage (RM), according to fetal chromosome karyotypes and aetiologies of RM.

METHODS

In this cohort study, 168 fetal chromosome karyotypes of miscarriages were investigated. The pregnancy loss patterns were compared between 75 miscarriages from RM women who had a history of two or more consecutive miscarriages and 93 miscarriages from control women whose previous pregnancies ended in live births without a history of RM. By serial ultrasonography, embryo loss (EL) was defined as miscarriage before fetal heat movement was identified and fetal loss (FL) as miscarriage after fetal heat movement was identified. The EL rate was calculated as EL/(EL+FL).

RESULTS

The EL rate (66.7%) in miscarriages with normal karyotypes among RM women (n=42) was higher (P<0.05) than that (45.7%) in controls (n=46), while the EL rate (30.3%) in miscarriages with abnormal karyotypes among RM women (n=33) did not differ from that (25.5%) in the controls (n=47). The EL rate (71.4%) in miscarriages with normal karyotypes among unexplained RM women (n=21) was much higher (P<0.05) than that in the controls.

CONCLUSIONS

By evaluating fetal karyotypes, we demonstrated for the first time that EL was predominant in miscarriages with normal karyotype among RM women.

Is trophoblastic thickness at the embryonic implantation site a new sign of negative evolution in first trimester pregnancy?

In this study a new sign to evaluate the evolution of pregnancy is described: the trophoblastic thickness at the embryonic implantation site. A prospective, observational study of 592 normal pregnancies with no known risk factors was carried out from January 1998 to February 1999. Serial ultrasound scans were performed from week 5 to week 12 of pregnancy. Trophoblastic thickness was measured at the embryonic implantation site to determine the significance of a difference in gestational age in weeks and a trophoblastic thickness of >/=3 mm in predicting poor prognosis in pregnancy outcome. The sensitivity of this sign in the prediction of spontaneous abortion was 82%, the specificity was 93%, the positive predictive value was 63% and the negative predictive value was 97%.

Chromosomal analysis of early fetal losses in relation to transvaginal ultrasonographic detection of fetal heart motion after infertility

OBJECTIVE

To evaluate the prognostic value of transvaginal ultrasound (TVUS) detection of fetal heart motion (FHM) in view of maternal age and chromosomal analysis of spontaneously aborted fetal tissue.

DESIGN

A 3-year retrospective, descriptive study.

SETTING

Two medical center-based infertility-care facilities.

PATIENT(S)

336 pregnancies were initiated by intrauterine insemination or embryo transfer for women of reproductive age who were seeking infertility treatment.

INTERVENTION(S)

None.

MAIN OUTCOME MEASURE(S)

beta hCG levels measured > 40 mIU/mL at 4-5 weeks' gestation and were followed by an initial TVUS at 5-8 weeks. Of these pregnancies, 52 ended in a first trimester loss. Twenty were defined by failure to detect FHM by 7 weeks' gestation (Group I), and 32 were marked by the loss of prior FHM at a mean of 2.6 weeks later (Group II). Fetal tissue was removed by dilatation and suction curettage. Cytogenetic studies were performed from short-term cultures of dissected chorionic villi and/or sac.

RESULT(S)

Chromosomal aberrations were found in 75.0% of abortuses in Group I and 65.6% in Group II. Different types of chromosomal abnormalities were present in each these groups. The maternal age-related trisomies which can progress to term (i.e., 13, 18, 21) were associated with early TVUS detection of FHM. The frequency of chromosomal abnormalities varied significantly with maternal age, with normal fetal karyotypes in 7 of 11 (63.6%) women < 35 years, but only in 9 of 41 (22.0%) women > or = 35 years despite the detection of FHM in 24 of 41 (58.5%) of these older women. Detection of FHM was associated with pregnancies continuing beyond the first trimester in 284 of 316 (90.0%) overall, but differed significantly with age (166 of 174 [95.4%] women < 35 years vs. 118 of 142 [83.1%] women > or = 35 years).

CONCLUSION(S)

Although the occurrence of chromosomal abnormalities in spontaneous demises did not differ according to TVUS detection of FHM, the types of aberrations were distributed differently. Since maternal age remains a significant factor in early fetal loss, TVUS detection of FHM should not be as reassuring for women > or = 35 years as for younger women.