Relationship of intertwin crown-rump length discrepancy to chorionicity, fetal demise and birth-weight discordance

OBJECTIVES

To study the frequency and clinical significance of crown-rump length (CRL) discrepancy at 11-14 weeks of gestation in twin pregnancies from an unselected population.

METHODS

This was a retrospective analysis of all twin pregnancies that underwent a routine 11-14-week scan at a large teaching hospital. Fetal loss was defined as fetal demise of one or both twins after 14 weeks.

RESULTS

A total of 507 twin pregnancies were studied; 382 (75.3%) were dichorionic and 125 (24.7%) were monochorionic twins. The discrepancy in CRL was expressed as a percentage of the CRL of the larger twin. The 95(th) and 99(th) centile for CRL discrepancy in twins was 12.2% and 19.3%, respectively. The discrepancy in CRLs in monochorionic and dichorionic twins was not significantly different (Mann-Whitney U = 22,406, P = 0.302). In 39 twin pairs, there was subsequent intrauterine death of one or both twins. Fetal loss was more common in monochorionic twins (24/125) than in dichorionic twins (15/382) (chi-square = 30.9, P < 0.001). In monochorionic twins, the discrepancy in CRLs in the 24 cases with subsequent loss was significantly greater than in the 101 twin pairs with no subsequent loss (Mann-Whitney U = 896, P = 0.048). The discrepancy in CRLs in 15 dichorionic twins with subsequent loss was not different from that in the 367 twins with no loss (Mann-Whitney U = 2116.5, P = 0.129). The CRL discrepancy was significantly correlated with birth-weight discordance in twins (Spearman's rho = 0.128, P = 0.006). However, this was due to a significant correlation in dichorionic twins (Spearman's rho = 0.127, P = 0.016) but not in monochorionic twins (Spearman's rho = 0.145, P = 0.14).

CONCLUSIONS

Fetal loss is significantly associated with discrepancy in CRL at the 11-14-week scan in monochorionic twins and discordance in birth weights is significantly associated with discrepancy in CRL in dichorionic twins. However, intertwin CRL discrepancy is of limited value in screening for these adverse events.

The effect of anticoagulation on antenatal ultrasound findings in pregnant women with thrombophilia

OBJECTIVE

To assess whether treatment with heparin alters ultrasound findings in pregnant women with inherited thrombophilia.

METHODS

This was a retrospective study of a cohort of patients referred for pregnancy complications who were found to have genetic thrombophilia. Ultrasounds were reviewed in treated and untreated pregnancies for the presence of growth restriction, oligohydramnios or abnormal Doppler results.

RESULTS

There were a total of 178 pregnancies in 51 patients. The overall percentage of abnormal ultrasounds was significantly greater in the untreated compared with treated pregnancies (52.8% vs. 27.9%; p = 0.024.) Growth restriction and abnormal Doppler results were more common in untreated pregnancies. There was a significantly decreased risk of oligohydramnios with treatment (27.3% vs. 7%; p = 0.03). Overall outcomes were significantly improved with the use of anticoagulation ( p < 0.0001).

CONCLUSIONS

Treatment markedly improves ultrasound parameters of growth, fluid and feto-placental blood flow in patients with thrombophilia. The presence of abnormalities despite treatment reinforces the need for close antenatal surveillance.

Twin pregnancy with fetus papyraceous

A successful pregnancy outcome with vaginal delivery of a term single live fetus in case of twin pregnancy with other twin papyraceous, (vanished in second trimester) is an uncommon finding. Ten percent of all perinatal deaths are related with dizygotic twins. The rate of intrauterine fetal demise in multiple pregnancies is as high as three times of monozygotic. Most frequently used and suggested method is follow-up of the maternal coagulation system by a series of lab test. Sonography is a visual tool to confirm the diagnosis. In case of monofetal death of twin pregnancies, the type of placenta should be analysed and then follow up and treatment modalities of these cases should be choosen.

Ultrasonographic fetal well-being assessment, neonatal and postpartum findings of cloned pregnancies in cattle: a preliminary study on 10 fetuses and calves

Cloned pregnancies in cattle are considered to be at risk due to a variety of fetal or adnexal abnormalities. Data is lacking concerning the possibility of transabdominal ultrasonography in the assessment of these high risk pregnancies. Transabdominal ultrasonography has rarely been reported in the assessment of bovine cloned pregnancies. Ten Holstein heifers carrying 8-month-old cloned fetuses were assessed by transabdominal ultrasonographic examination during the 3rd trimester of pregnancy. Fetal heart rates (FHR), movements, adnexal appearance, and placentome size were recorded. The outcome of the pregnancies was also noted and potential indicators of fetal demise recorded. Survival rate 1 week after birth was 30%. Mean FHR was 113 beats per minute (range: 92 to 128 bpm) during the fetal ultrasonography. No correlation between FHR and fetal activity was found. Fetal hyperactivity and imaging of hyperechoic particles in both allantoic and amniotic fluids were possible signs of fetal distress. Despite the size of the fetus and the deep bovine abdomen, fetal transabdominal ultrasonography can be performed in cattle. This preliminary study points to the necessity of further larger studies for defining normal and abnormal findings in bovine late pregnancy.

Five-millimeter and smaller embryos without embryonic cardiac activity: outcomes in women with vaginal bleeding

OBJECTIVE

The purpose of this study was to assess outcomes in embryos with a crown-rump length (CRL) of 5 mm or less without embryonic cardiac activity (ECA) among pregnant women with vaginal bleeding in the first trimester.

METHODS

A retrospective study of all first-trimester sonograms in women with vaginal bleeding from 1999 to 2002 was conducted.

RESULTS

Thirty-seven embryos without detectable ECA that had a CRL of 5 mm or less were identified. All resulted in pregnancy failure. The breakdown of these embryos by CRL was as follows: 13 were 5 mm; 10 ranged from 4 to 4.9 mm; 11 ranged from 3 to 3.9 mm; and 3 ranged from 2 to 2.9 mm.

CONCLUSIONS

In pregnant women with vaginal bleeding, embryos of 5 mm and smaller without a heartbeat all resulted in pregnancy failure.

Color Doppler twinkling artifact in intrauterine fetal demise

PURPOSE

To determine whether twinkling artifacts on color and power Doppler sonography could be used as a new sonographic sign of intrauterine fetal demise (IUFD).

METHODS

In this prospective study, 24 consecutive pregnant women with IUFD were included after fetal sonographic examinations. Sonographic examination included gray-scale, color, power, and spectral Doppler imaging. The sonograms were then analyzed for the presence, appearance, and intensity of the twinkling artifacts.

RESULTS

Twinkling artifacts on color Doppler were observed in all of the 24 IUFD as a rapidly changing color Doppler signal complex associated persistently with different parts of the fetal body. The artifacts were localized especially in the neck, back, and iliac regions. Artifact intensity correlated with the time elapsed since death.

CONCLUSION

Twinkling artifact was noted in all dead fetuses on color, power, and spectral Doppler examinations. Thus, the observation of these artifacts may be considered as a new sonographic sign of fetal demise, which may reflect the time elapsed since death.

Nuchal translucency thickness in monochorionic multiple pregnancies: value in predicting pregnancy outcome

OBJECTIVES

The purpose of this study was to investigate the value of first-trimester nuchal translucency (NT) thickness in predicting the pregnancy outcome in monochorionic multiple pregnancies.

METHODS

Thirty monochorionic multiple pregnancies were evaluated for NT thickness at a median gestational age of 12 weeks (range, 11-14 weeks). Information on pregnancy outcome was obtained from all cases. A poor pregnancy outcome was defined as fetal death or miscarriage before 24 weeks, development of twin-twin transfusion syndrome (TTTS), or preterm delivery before 32 weeks.

RESULTS

The NT thickness was above the 95th percentile for gestational age in at least 1 fetus in 5 (17%) pregnancies, and a poor pregnancy outcome was recorded in 14 (47%) pregnancies. The overall sensitivity was 36% (5/14); specificity, 100% (16/16); positive predictive value, 100% (5/5); and negative predictive value, 64% (16/25). In pregnancies with increased compared with normal NT thickness, no significant correlation was found with the subsequent development of TTTS (1/5 [20%] versus 5/25 [20%]) and miscarriage or fetal death before 24 weeks (1/5 [20%] versus 3/25 [12%]). However, among the 20 pregnancies not complicated by TTTS or loss before 24 weeks, there was a significantly increased rate of delivery before 32 weeks in the former group (3/4 [75%] versus 1/16 [6.3%]; P = .01).

CONCLUSIONS

In monochorionic multiple pregnancies, an increased NT thickness measurement had a high specificity and positive predictive value for adverse perinatal outcomes. However, the sensitivity and negative predictive value were low, with a normal NT thickness measurement poorly predicting development of complications; therefore, close sonographic follow-up should be carried out in all cases, irrespective of NT thickness.

Relationship between crown-rump length and early detection of cardiac activity

OBJECTIVE

To investigate whether improvements in sonographic technology would allow detection of embryonic demise at a crown-rump length (CRL) < 5 mm.

STUDY DESIGN

A prospectively collected, computerized ultrasound database was queried for singleton gestations with CRL < or = 5 mm from January 2000 to February 2003. Embryonic viability was determined by repeat ultrasound examination after 6 weeks'gestation confirming cardiac activity or by documentation of an ongoing pregnancy. Viability rates in the presence or absence of cardiac activity were calculated for CRL of 2.0-2.9, 3.0-3.4, 3.5-3.9, 4.0-4.4, 4.5-4.9 and 5.0 mm. Sensitivity, specificity, positive predictive value and negative predictive value for embryonic demise were calculated, with a subanalysis based on the presence of vaginal bleeding.

RESULTS

Outcome was available for 179 of 195 gestations meeting inclusion criteria. The absence of cardiac activity at CRL > or = 3.5 mm had 100% positive predictive value and specificity. The presence of vaginal bleeding did not affect this cutoff.

CONCLUSION

Improved sonographic technology permits diagnosis of embryonic demise at a CRL > or = 3.5 mm under ideal conditions. Vaginal bleeding increases the likelihood of demise, but does not alter test performance. Further investigation is warranted, as our data suggest a limit closer to 3 mm.

Discordance in nuchal translucency thickness in the prediction of severe twin-to-twin transfusion syndrome

OBJECTIVE

To examine in monochorionic pregnancies the possible value of intertwin discordance in nuchal translucency (NT) thickness in the prediction of early fetal death or severe twin-twin transfusion syndrome (TTTS).

METHODS

In 512 monochorionic twin pregnancies NT was measured at 11 to 13 + 6 weeks' gestation and regression analysis was used to determine the significance of the association between the intertwin discordance in NT and subsequent early fetal death or development of severe TTTS requiring endoscopic laser surgery.

RESULTS

In 412 (80.5%) pregnancies there was a normal outcome, in 58 (11.3%) there was severe TTTS requiring endoscopic laser surgery at 18-24 weeks, in 19 (3.7%) there was death of one or both fetuses at 13-18 weeks and in 23 (4.5%) there was fetal death at 21-38 weeks. In the four outcome groups the median discordance in NT was 11%, 22%, 35% and 7%, respectively. Significant prediction of early fetal death and severe TTTS was provided by the discordance in fetal NT, which was not significantly improved by including the discordance in crown-rump length. If the discordance in NT was 20% or more, the false positive rate was 20%, the detection rate of early fetal death was 63% and the detection rate of severe TTTS was 52%.

CONCLUSIONS

Discordance in NT of 20% or more is found in about 25% of monochorionic twins and in this group the risk of early fetal death or development of severe TTTS is more than 30%. If the discordance is less than 20% the risk of complications is less than 10%.

[Intrauterine intestinal volvulus and fetus compressus papyraceus in twins]

Intrauterine intestinal volvulus and fetus compressus papyraceus in twins. In a double twin pregnancy revealed on the 16th gestation week by ultrasound examination, a foetus papyraceus was detected on the 20th gestation week in a 29 year old woman. On the 32nd gestational week two monochorionic-diamniotic male stillborn twins were born. One of them (15 cm/35 g) was rudimentary developed and compressed. On examination of the other (39 cm/1485 g) partially macerated foetus, volvulus of small intestine with hemorrhagic necrosis was found at the autopsy. Both of the anomalies are very rare.

[Umbilical cord entanglement in monoamniotic twin preganacy--case presentation and literature review]

Monoamniotic twins are at most increased risk of perinatal complications with perinatal mortality of 28-60 % reported in literature. The most specific complication to monoamniotic twins is entanglement and (or) knotting of the cords leading to intrauterine death of both (more often) or one twin. In first presented case 1, 23-year-old primigravida in 33wks of twin monoamniotic gestation was reffered to our Institute due to intrauterine death of one co-twin caused by umbilical cord entanglement. In second case, 26-year-old multigravida in monoamniotic twin gestation was admitted to our institution. A serious umbilical cord entanglement was observed and a presence of true knot of umbilical cord was suspected. Presented cases indicate that establishing a chorionicity and amniocity in twin pregnancy is an essential part of ultrasound examination. The diagnosis of cord entanglement in monoamniotic twin pregnancy enables a forecasting of possible complications. According to the established diagnosis future protocols of perinatal management could be proposed. Due to possible complications counseling and management of monoamniotic twins should be performed in tertiary medical centers.

Medical treatment for early fetal death (less than 24 weeks)

BACKGROUND

In most pregnancies that miscarry, arrest of embryonic or fetal development occurs some time (often weeks) before the miscarriage occurs. Ultrasound examination can reveal abnormal findings during this phase by demonstrating anembryonic pregnancies or embryonic or fetal death. Treatment before 14 weeks has traditionally been surgical but medical treatments may be effective, safe, and acceptable, as may be waiting for spontaneous miscarriage.

OBJECTIVES

To assess the effectiveness, safety and acceptability of any medical treatment for early pregnancy failure (anembryonic pregnancies or embryonic and fetal deaths before 24 weeks).

SEARCH STRATEGY

We searched the Cochrane Pregnancy and Childbirth Group Trials Register (30 November 2005).

SELECTION CRITERIA

Randomised trials comparing medical treatment with another treatment (e.g. surgical evacuation), or placebo, or no treatment for early pregnancy failure. Quasi-random studies were excluded.

DATA COLLECTION AND ANALYSIS

Data were extracted unblinded.

MAIN RESULTS

Twenty four studies (1888 women) were included. Vaginal misoprostol hastens miscarriage (complete or incomplete) when compared with placebo: e.g. miscarriage less than 24 hours (two trials, 138 women, relative risk (RR) 4.73, 95% confidence interval (CI) 2.70 to 8.28), with less need for uterine curettage (two trials, 104 women, RR 0.40, 95% CI 0.26 to 0.60) and no significant increase in nausea or diarrhoea. Lower-dose regimens of vaginal misoprostol tend to be less effective in producing miscarriage (three trials, 247 women, RR 0.85, 95% CI 0.72 to 1.00) with similar incidence of nausea. There seems no clear advantage to administering a 'wet' preparation of vaginal misoprostol or of adding methotrexate, or of using laminaria tents after 14 weeks. Vaginal misoprostol is more effective than vaginal prostaglandin E in avoiding surgical evacuation. Oral misoprostol was less effective than vaginal misoprostol in producing complete miscarriage (two trials, 218 women, RR 0.90, 95% CI 0.82 to 0.99). Sublingual misoprostol had equivalent efficacy to vaginal misoprostol in inducing complete miscarriage but was associated with more frequent diarrhoea. The two trials of mifepristone treatment generated conflicting results. There was no statistically significant difference between vaginal misoprostol and gemeprost in the induction of miscarriage for fetal death after 13 weeks.

AUTHORS' CONCLUSIONS

Available evidence from randomised trials supports the use of vaginal misoprostol as a medical treatment to terminate non-viable pregnancies before 24 weeks. Further research is required to assess effectiveness and safety, optimal route of administration and dose. Conflicting findings about the value of mifepristone need to be resolved by additional study.

Perinatal outcome associated with sonographically detected globular placenta

OBJECTIVE

To evaluate the association between the sonographic appearance of globular placenta and perinatal outcome.

STUDY DESIGN

We prospectively followed the pregnancy course and perinatal outcome in women with globular placentas (hyperechoic, thick and highly vascular placentas with edges that lack the typical "tapering" appearance) during routine sonographic study.

RESULTS

Fourteen women were included. In 7 women the globular appearance of the placenta normalized spontaneously, and perinatal outcome was good. The other 7 experienced poor perinatal outcomes. There were no significant differences between the 2 groups. Among pregnancies in which the globular placental appearance persisted, 3 resulted in fetal demise; 3 women had severe intrauterine growth restriction and oligohydramnios and underwent cesarean deliveries at 26, 27 and 31 weeks, respectively; and 1 patient had premature preterm rupture of membranes and underwent a cesarean delivery due to placental abruption.

CONCLUSION

In half the pregnancies complicated by the sonographic appearance of a globular placenta, this shape spontaneously normalized, and the perinatal outcome was normal. However, when the globular appearance of the placenta persisted, the condition was associated with a poor perinatal outcome. Pregnancies complicated by a globular placenta should be followed closely.

Is Small for Gestational Age a Marker of Future Fetal Survival In Utero?

OBJECTIVE

We sought to assess whether small for gestational age is a risk factor for stillbirth of a subsequent sibling.

METHODS

The Missouri maternally linked cohort data set, containing data on births from 1978 through 1997, was used. We identified the study group (women who delivered a SGA infant in the first pregnancy) and a comparison group (women who delivered a non-SGA infant in their first pregnancy) and compared the outcome (stillbirth) in the second pregnancy between both groups.

RESULTS

We analyzed information on the first and second pregnancies of 402,015 women (43,549 [10.8%] in the study arm and 358,466 [89.2%] in the comparison arm). Of the 1,883 cases of stillbirth in the second pregnancy, 314 cases occurred in mothers with a history of SGA (stillbirth rate 7.2/1,000) and 1,569 in the comparison group (stillbirth rate 4.4/1,000), P < .001. The adjusted risk of stillbirth was 60% higher in women with a prior SGA (odds ratio [OR] 1.6, 95% confidence interval [CI] 1.4-1.8). The risk for stillbirth in the second pregnancy increased with decreasing gestational age at birth of the SGA infant in the first pregnancy (term: OR 1.4, 95% CI 1.2-1.6; preterm: OR 2.8, 95% CI 2.0-3.8; and very preterm: OR 4.2, 95% CI 2.4-7.3), P for trend < .001.

CONCLUSION

Small for gestational age is a marker for subsequent stillbirth, and the risk rises with decreasing gestational age of the SGA birth. This information is potentially useful for counseling parents of SGA infants.

LEVEL OF EVIDENCE

II-2.

Relationship between heat stress during the peri-implantation period and early fetal loss in dairy cattle

The aim of the present study was to establish whether temperature-humidity index values, as a measure of heat comfort, from Days 1 to 40 of gestation could be associated with the pregnancy loss rate in high producing dairy cows. Data from 1391 pregnancies were recorded. Pregnancy was diagnosed by transrectal ultrasonography between Days 34 and 45, and again 90 days after insemination. Pregnancy loss was assumed when the second pregnancy diagnosis on Day 90 proved negative and was registered in 7.8% (108/1391) of pregnancies. Mean and maximum temperature-humidity index values were established for each cow for Days 0 (day of insemination), 1, 2 and 3 after insemination, and averages established for Days 0-3, 0-10, 11-20, 21-30 and 31-40 after insemination. Cow and management variables previously found to be significantly correlated with the early fetal loss in the same geographical area were also recorded. The relative contribution of each factor to the probability of pregnancy loss was determined using logistic regression models. Based on the odds ratio, a strong association with pregnancy loss of the factors warm period of pregnancy (warm period-May to September versus cool-October to April), twin pregnancy (as negative factors: odds ratios 3.1 and 3.4, respectively) and an additional corpus luteum (as a positive factor: odds ratio 0.32) was confirmed. The likelihood of pregnancy loss increased by a factor of 1.05 for each additional unit of the mean maximum temperature-humidity index from Days 21 to 30 of gestation. Logistic regression analysis revealed no significant effects of temperature-humidity index values for the remaining gestation periods. Our results indicate that heat stress can compromise the success of gestation during the peri-implantation period, such that high temperature-humidity index values for the period 21-30 days of gestation are a risk factor for subsequent early fetal loss.

Radiography following perinatal death: a review

Radiography of the perinatally dead infant provides detailed information about the skeleton and is valuable as an adjunct to autopsy. This article reviews the potential benefits and discusses the pitfalls in assessment of growth stage. Reference charts for individual bone lengths and secondary ossification centers are presented.

Wernicke's encephalopathy: beyond alcoholism

BACKGROUND

A 17-year-old pregnant woman presented to hospital at 19 weeks' gestation with an 8-week history of hyperemesis gravidarum, 16.8 kg of weight loss, and new-onset weakness, dizziness and blurred vision. Examination of the patient showed confusion, papilledema, ophthalmoparesis, nystagmus, reduced hearing and truncal ataxia.

INVESTIGATIONS

Physical examination, abdominal ultrasound, fetal ultrasound, brain MRI, magnetic resonance angiography, magnetic resonance venography and cerebrospinal-fluid analysis.

DIAGNOSIS

Wernicke's encephalopathy, hyperemesis gravidarum and fetal loss.

MANAGEMENT

Intravenous thiamine repletion and elimination of deficiency risk factors.

Termination of second trimester, complicated gestation

To assess the effectiveness of intravaginal misoprostol for second trimester uterine evacuation, we studied 70 women with singleton pregnancies complicated by fetal malformation or dead fetuses. Participants received 200 microg misoprostol administered at 4-hour intervals. Gestations with dead fetuses had a shorter induction-abortion interval [14.2 hours, standard deviation (SD) 4.3] than those with live, malformed fetuses (20.2 hours, SD 7.3) (P< 0.001). The abortion rate was significantly higher for gestations with dead fetuses (92.1%) than those with live, malformed fetuses (68.8%) (P< 0.05). There were no major complications and no significant difference in the incidence of side-effects. All women aborted within 38 hours. Administration of misoprostol is an effective clinical method to terminate second trimester, complicated pregnancy.

Prenatal diagnosis and obstetric outcomes in triplet pregnancies in relation to chorionicity

OBJECTIVE

This study describes the frequency, pregnancy complications and outcomes of non-trichorionic triplet pregnancies.

DESIGN

A retrospective observational study.

SETTING

Two tertiary level referral centres of Obstetrics and Prenatal Medicine, Germany.

POPULATION

All women booked to receive targeted ultrasound screening between January 1998 and June 2003. The mixed low and high risk population included 36,430 women with ultrasound examinations between 11 and 24 weeks of gestation. Of those with available outcome, 176 were triplet pregnancies with three viable fetuses.

METHODS

Analysis of ultrasound data and perinatal outcome in triplet gestations who had first and second trimester targeted ultrasound examination. Pregnancies with monochorionic or dichorionic placentation were identified and pregnancy outcome was compared to trichorionic triplets.

MAIN OUTCOME MEASURES

Intrauterine fetal death, fetal growth restriction (FGR), mean discordance and survival rate in non-trichorionic versus trichorionic triplets.

RESULTS

Triplets were trichorionic in 81.8% and had a monochorionic or dichorionic placentation in the remaining 18.2%. The rate of monochorionicity and dichorionicity was significantly higher after spontaneous conception than after assisted reproductive technologies (44.8%vs 12.9%, P < 0.001). In non-reduced monochorionic and dichorionic triplets compared with non-reduced trichorionic triplets, there was a higher rate of intrauterine fetal death (8.8%vs 1.5%, P < 0.01), FGR (33.3%vs 25.5%), mean discordance (20.5%vs 12.7%, P < 0.01), discordance >30% (26.3%vs 2.9%, P < 0.01) and delivery <32 weeks of gestations (47.4%vs 32.2%). There was a lower survival rate in non-trichorionic triplets (84.2%) than in trichorionic ones (91.7%).

CONCLUSION

Triplet pregnancies with a monochorionic or dichorionic placentation are at significantly higher risk of adverse pregnancy outcome compared with trichorionic pregnancies. First trimester evaluation of chorionicity is strongly emphasised.

Fetal mortality diagnosis by ultrasound in the vicuña (Vicugna vicugna)

Ultrasonography is widely used in domestic species of camelids, but there is no information about the use of this technique for pregnancy diagnosis and determination of embryonic or fetal losses in the vicuña (Vicugna vicugna). The study was performed in 202 vicuñas (3-year-old females, n = 31; adult females, n = 171) mated during the summer months (January through March 2001) at the Abra Pampa Experimental Farm of Altitude in north-west Argentina. Transrectal ultrasound examination was performed in May (estimated 40-120 days of gestation) to determine the number of pregnant females. The pregnancy rate was 45.5% (92/202). No significant difference (P > 0.05) was observed between the pregnancy rate of 3-year-old females (41.9%) and adult females (46.2%). In December (estimated 250-330 days of gestation) of the same year, a second ultrasonographic study was performed on those vicuñas that were diagnosed as pregnant from the first ultrasound scan. Of 92 animals diagnosed as pregnant in May, only 84 were present in December, because eight females died in the period of study. Overall, 11.9% (10/84) of fetuses were lost during the period (18.1% in 3-year-old vicuñas and 10.9% in adult vicuñas). In conclusion, transrectal ultrasonography was found to provide a rapid and non-invasive means for pregnancy and fetal mortality diagnosis in vicuñas.

Spontaneous reduction of advanced twin embryos: its occurrence and clinical relevance in dairy cattle

Twin pregnancies represent a management problem in dairy cattle since the risk of pregnancy loss increases, and the profitability of the herd diminishes drastically as the frequency of twin births increases. The aim of this study was to monitor the development of 211 twin pregnancies in high producing dairy cows in order to determine the best time for an embryo reduction approach. Pregnancy was diagnosed by transrectal ultrasonography between 36 and 42 days after insemination. Animals were then subjected to weekly ultrasound examination until Day 90 of gestation or until pregnancy loss. Viability was determined by monitoring the embryonic/fetal heartbeat until Day 50 of pregnancy, and then by heartbeat or fetal movement detection. Eighty-six cows (40.8%) bore bilateral and 125 (59.2%) unilateral twin pregnancies. Embryo death was registered in one of the two embryos in 35 cows (16.6%), 33 of them at pregnancy diagnosis. Pregnancy loss occurred in 22 of these cows between 1 and 4 weeks later. Thus, 13 (6.2% of the total animals) cows, carrying one dead of the two embryos, maintained gestation. Total pregnancy loss before Day 90 of pregnancy (mean 69 +/- 14 days) was registered in 51 (24.2%) cows: 7 (8%) of bilateral pregnancies and 44 (35.2%) of unilateral pregnancies, and it was higher (P = 0.0001) for both right (32.4%, 24/74) and left (39.2%, 20/51) unilateral than for bilateral (8.1%, 7/86) twin pregnancies. The single embryo death rate was significantly (P = 0.02) lower for cows with bilateral twins (9.3%, 8/86) than for total cows with unilateral twins (21.6%, 27/125). By way of overall conclusion, embryo reduction can occur in dairy cattle, and the practical perspective remains that most embryonic mortality in twins (one of the two embryos) occurs around Days 35-40 of gestation, the period when pregnancy diagnosis is generally performed and when embryo reduction could be tried.

[Reverse flow in fetal vessels and perinatal events]

BACKGROUND/PATIENTS: A reverse flow in the umbilical artery and/or fetal aorta is associated with a higher perinatal and neonatal mortality. 30 fetuses showed a reverse flow using pulsed wave Doppler sonography (group I). A matched-pair control group including 30 fetuses with the same gestational age as well as a normal Doppler flow pattern in the umbilical artery and/or fetal aorta was taken for comparison (group II).

RESULTS

In the group with reverse flow the rates of pregnancies with pre-eclampsia (n = 19/30, p < 0.0001), intrauterine growth retardation (n = 25/30, p < 0.0001), oligohydramnios (n = 21/30, p < 0.0001) and nicotine abuse (n = 15/30, p < 0.01) were significantly higher compared to the control group. Postnatal data showed significantly lower pH values in group I (p < 0.01). 40 % of the fetuses with reverse flow died in utero whereas in 67 % the reverse flow was accompanied by an insufficiency of the placenta (IUGR, oligohydramnios, histopathological abnormalities of the placenta). None of the fetuses in the control group died in utero. The incidence of IUGR (< 5ht percentile) was 83 % in group I but only 3 % in group II. The perinatal and overall mortality (including neonatal mortality 7 - 28 days after birth) amounted to 27 % and 53 % in group I, respectively, compared to 3 % and 0 % in the control group (p < 0.001). In addition cerebral anomalies could be found by ultrasound in 50 % of the neonates who presented a reverse flow prenatally. In 28 % of the surviving newborns an intracerebral hemorrhage (ICH) could be detected. None of the newborns of group II developed an ICH.

CONCLUSIONS

Pregnancies with a reverse flow in the umbilical artery and/or fetal aorta have to be considered as a high risk group with a poor prognosis. The reverse flow is mainly caused by chronic placental insufficiency with IUGR. With respect to the further neuromotor development the incidence and severity of cerebral lesions in affected fetuses should be considered when discussing the perinatal situation with the parents.

Differential Transmission of Parvovirus B19 in a Twin Gestation: A Case Report

Maternal infection with parvovirus B19 during pregnancy can cause aplastic anemia in the fetus. Severe anemia may lead to nonimmune hydrops or fetal demise. In the case reported, the demise of one twin was diagnosed by ultrasonography in an asymptomatic 21-year-old para 1-0-2-1 African American at the gestational age of 25 weeks. The deceased twin (A) was grossly hydropic with anasarca, ascites, pleural and pericardial effusions, and a thickened placenta. Parvovirus B19 DNA was found in the amniotic fluid of Twin A using the polymerase chain-reaction technique. Serial scans of Twin B showed normal growth and no evidence of hydrops. The pregnancy was managed expectantly until 29 weeks when delivery was indicated by maternal disseminated intravascular coagulation. Maternal IgM antiparvovirus B19 antibodies were detected at the time of delivery. Antiparvovirus B19 IgM antibodies were not present in Twin B. These serologic studies suggest a recent acute maternal infection and refute such an infection in Twin B. We present a case of differential transmission of parvovirus B19 in a twin pregnancy with in utero death of the infected twin and subsequent maternal disseminated intravascular coagulation.