Perinatal results following the prenatal ultrasound diagnosis of single umbilical artery

OBJECTIVE. To study the perinatal results in our population, following the prenatal ultrasound diagnosis of a single umbilical artery (SUA), as this alteration is associated with fetal malformations, chromosomal abnormality, and poor perinatal results. MATERIALS AND METHODS. A retrospective review of all obstetric ultrasounds carried out between October 2000 and December 2003 in our service, obtaining the postnatal results of the fetuses diagnosed with an SUA. RESULTS. From a total of 5,987 pregnant patients examined by ultrasound scan at 20th week, an SUA was found in 40 cases, representing an incidence of 0.7%. Of these, 84.6% were normal pregnancies at birth and 15.4% presented other malformations and/or chromosomal abnormalities. No aneuploidy was found in pregnancies where there were no other associated findings in the ultrasound scan at 20 weeks. All cases with serious congenital malformations accompanying the SUA were diagnosed prenatally. There was a 5% of perinatal mortality rate among our fetuses with SUA, which represents a mortality rate 10 times greater than the overall rate among our patients. CONCLUSIONS. The ultrasound discovery of an SUA implies the meticulous search for other associated malformations, and in the absence of these, the risk of a chromosomal abnormality is very low, unless it is a high-risk patient. However, the growth and wellbeing of the fetus must be carefully monitored in the last 3 months, although the ultrasound scan does not show any other associated alterations.     

Single umbilical artery: review of 12 cases

The umbilical cord normally consists of three vessels, two arteries and one vein. The absence of one umbilical artery or single umbilical artery (SUA) has been associated with some adverse perinatal events, such as low birth weight, prematurity, congenital malformations and perinatal mortality. The authors present 12 cases of SUA confirmed by histologic examination and the principal maternal and perinatal features of these cases are analyzed. In our study there were a prematurity rate of 58%, a low birth weight rate of 66% and a perinatal mortality rate of 580/1000. Among our patients, 42% of the infants with SUA had major congenital malformations. An accurate examination of the umbilical cord at delivery is suggested, mainly because SUA is an important index to detect associated congenital malformations.     

Outcomes of an isolated single umbilical artery in singleton pregnancy: a large study from the Middle East and Gulf region

Objective

To assess the frequency and accuracy of prenatal diagnosis of a single umbilical artery (SUA) and to compare the fetal and neonatal outcome of isolated SUA to that of a normal three-vessel umbilical cord in a population from the Middle East and Gulf region.

Study design

Data were collected from 37,500 singleton pregnancies that were scheduled for antenatal care and delivered at Security Forces Hospital in Riyadh, Saudi Arabia, between May 2004 and December 2012. Comparisons between the groups were performed using a chi-square test or a Fisher exact test for the categorical variables, and Student's t test or Wilcoxon's rank-sum test were used for continuous variables. The Kappa statistic was used to study the agreement between the antenatal and final neonatal diagnosis of SUA. A univariable analysis was used to calculate the unadjusted and adjusted ORs and the 95% CIs expressing the relationship of the normal three-vessel umbilical cord, the isolated SUA, and each outcome.

Results

A total of 35,249 cases completed the study, including 35,026 cases with normal neonatal three-vessel umbilical cords (Group B). SUA was present in 223 (0.63%) neonates (0.45% isolated SUA (Group A) and 0.18% non-isolated SUA). The sensitivity, specificity, positive predictive value and negative predictive value of using prenatal ultrasound for the diagnosis of SUA were 90.58%, 99.9%, 98.5% and 99.94%, respectively. Neonatal anomaly was present in 2.6% of the fetuses with isolated SUA. A pregnancy with isolated SUA was more likely to be complicated with polyhydramnios (OR 3.32; CI 1.22–9.04), preterm delivery <34 weeks (OR 4.662; CI 2.346–9.195), birth weight <10th percentile (OR 2.1; CI 1.44–2.93), cesarean delivery for fetal distress (OR 2.72; CI 1.53–4.81), perinatal death (OR 3.31; CI 1.34–8.12), admission to NICU (OR 2.71; CI 1.87–3.91), and placental abnormalities (OR 3.25; CI 2.14–4.93; p value 0.0001) compared to a pregnancy with a fetal and neonatal three-vessel cord.

Conclusion

Isolated SUA is associated with anomalies at birth and with an increased risk of adverse pregnancy outcomes even in the absence of other anomalies. A pregnancy with this complication should receive close fetal monitoring for growth and fetal wellbeing.     

产前超声诊断单脐动脉与胎儿异常的相关性研究

目的探讨超声检测胎儿脐带血管数目预测胎儿先天异常的价值。方法2000年1月至2006年10月在中山大学附属第一医院采用超声检测胎儿脐血管数目，对单脐动脉胎儿行产前超声系统筛查及胎儿染色体检查；分析单脐动脉合并畸形类型，与染色体异常的关系及胎儿结局。结果产前超声诊断胎儿单脐动脉119例，包括左侧72例（60．5％），右侧47例（39．5％）。单纯性单脐动脉59例（49.6％）；合并其他结构畸形60例（50．4％），其中泌尿系统畸形25例（41．7％），心血管系统畸形17例（28.3％），中枢神经系统畸形15例（25.0％），下肢畸形9例（15．0％），前腹壁和消化道畸形各5例（各占8．3％），唇裂或唇腭裂畸形3例（5．0％），其他畸形3例（5．0％）。行胎儿染色体检查41例，发现染色体异常8例，包括18-三体综合征3例、13-三体综合征1例、21．三体综合征1例、染色体片段异常3例，均合并其他畸形。结论胎儿单脐动脉左侧发生率高于右侧，约50％合并其他畸形；合并畸形时，染色体异常发生率较高；大部分单纯性单脐动脉胎儿结局良好。     

Pregnancy outcome in isolated single umbilical artery

Our objective was to determine whether the rate of small for gestational age (SGA) infants and adverse perinatal outcome are increased in pregnancies diagnosed with an isolated single umbilical artery (SUA). We compared 297 pregnancies with a SUA diagnosed on routine obstetrical ultrasound with 297 pregnancies with a three-vessel cord control. Pregnancies complicated by major fetal anomalies were excluded. The rate of SGA, fetal death, and neonatal outcomes were compared between the two groups. Data analysis were performed using the T-test and chi-square test. The sample size had 80% power to detect a 50% difference between groups assuming a SGA rate of 20% in the SUA group and 10% in the control, alpha = 0.05. Among the SUA group, in 21 neonates (7.1%) the presence of a SUA could not be confirmed by postnatal examination, and 21 (7.1%) had major congenital anomalies, leaving 255 for final analysis. In the control group, 8 of the 297 (2.7%) had major congenital anomalies, leaving 289 for final analysis. The incidence of SGA neonates was 35 of 255 (13.7%) in the isolated SUA group compared with 38 of 289 (13.1%) in the control group ( P = 0.93). The composite perinatal outcomes (fetal death and/or SGA) were also similar between the groups (16.1% versus 14.5%; P = 0.72). We concluded that pregnancies with isolated SUA have a similar rate of SGA to those with 3VC.When a SUA is identified antenatally, a targeted ultrasound is warranted to rule out associated anomalies. Serial antepartum ultrasound for fetal growth is not necessary in managing pregnancies complicated by isolated SUA.     

Antenatal sonographic detection of single umbilical artery.

The absence of one umbilical artery of single umbilical artery (SUA) is one of the most common congenital malformations in man. This vascular anomaly of the umbilical cord is frequently associated with other congenital malformations as well as some adverse perinatal events such as intrauterine growth retardation (IUGR), premature delivery, and increased perinatal mortality. Five cases of SUA detected prenatally by ultrasound are reported here in detail, including the first reported case in a twin gestation. None of the 5 affected infants had associated anomalies, but 2 cases of intrauterine growth retardation (IUGR) and 1 stillborn infant were noted in this series. An umbilical vein/umbilical artery ratio less than 2 was invariably found in all cases, making this observation another useful sonographic characteristic to use in the antenatal detection of SUA. Since the umbilical cord can be easily seen prenatally by ultrasound, and SUA is recognized as an important index for detecting congenital malformations, examination of the umbilical cord for the absence of one umbilical artery is an extremely valuable tool in prenatal diagnosis. The prenatal detection of SUA demands an extensive search for associated anomalies and a close surveillance of fetal well-being, since these fetuses have a high risk of fetal death or IUGR. Sonologists and sonographers should be aware of the possibility of SUA, especially in those cases associated with congenital malformations or IUGR.     

Demographic and perinatal outcome data of fetuses with SUA/PRUV

Aim: Identify structural anomalies and adverse pregnancy outcomes accompanying single umbilical artery (SUA) and persistent right umbilical vein (PRUV) and to investigate whether SUA and PRUV are associated with chromosomal abnormalities and if these defects warrant invasive antenatal diagnosis.

Methods: We retrospectively analyzed pregnancies with an antenatal diagnosis of SUA/PRUV from the International Peace Maternity and Child Health Hospital (IPMCHH) database. Data of structural malformations, fetal karyotyping, and pregnancy outcomes were analyzed.

Results: Results revealed that 13.9 and 7% of SUA and PRUV cases, respectively, had malformations. Furthermore, 60% of the malformations accompanying SUA were isolated congenital heart disease (CHD), and 50% of the malformations accompanying PRUV were multiple malformations including CHD. All primarily diagnosed isolated PRUV (iPRUV) cases and 92.6% of primarily diagnosed iSUA cases had normal fetal echocardiography. Cases of iSUA and iPRUV with indications of invasive antenatal diagnosis showed no chromosomal abnormalities. The emergency cesarean section rate did not differ between the study population and the IPMCHH general population (p?=?.184).

Conclusion: Patients of SUA and PRUV diagnosed in secondary hospitals should be referred to tertiary medical center for further ultrasonography. SUA and PRUV are not indicators for invasive antenatal diagnosis and selective cesarean section.     

Fetal and neonatal outcomes in twin oligohydramnios-polyhydramnios sequence including cerebral palsy

OBJECTIVE: The purpose of this study was to review consecutive pregnancies complicated by twin oligohydramnios-polyhydramnios sequence (TOPS) and to clarify the probable factors influencing the perinatal outcomes. METHODS: Twenty-five pregnancies with a diagnosis of TOPS were treated with and without amniocentesis. A poor perinatal outcome was defined when either perinatal mortality or cerebral palsy was observed. RESULTS: The mean gestational age at the time of diagnosis and of delivery was 27.8 (range 21-34) and 30.7 (range 23-35) weeks, respectively. Tocolytic therapy and therapeutic amniocentesis were done in 16 (64%) and 13 (52%) cases. Hydrops fetalis was present in 10 cases. The survival rate was 72%, and cerebral palsy was diagnosed in 8 of 36 infants (22%). The poor prognostic factors were gestational age at delivery (<30 weeks) and presence of symptomatic preterm labor and hydrops fetalis. Therapeutic amniocentesis did not influence the perinatal outcome. CONCLUSIONS: In this observational study, the long-term as well as the short-term perinatal outcome of pregnancy with TOPS seems to be poor. In addition, therapeutic amniocentesis in TOPS does not appear to affect fetal and neonatal outcomes.     

Doppler velocimetry in the fetus with a single umbilical artery.

OBJECTIVE: To study Doppler velocimetry in fetuses with a single umbilical artery (SUA) as compared to normal. STUDY DESIGN: Private and clinic patients were referred to a perinatal center: 45 with SUA and 124 randomly selected fetuses with a three-vessel cord were studied from 18 to 41 weeks' gestation. Color Doppler flow and energy were utilized to evaluate the umbilical arteries at the fetal abdominal wall as well as the course around the bladder. In addition to Doppler velocimetry, an anatomic survey, estimated fetal weight (EFW) and amniotic fluid index (AFI) were assessed at each examination. RESULTS: Doppler velocimetry in SUA demonstrated indices in the normal range but lower than in normal cords from 26 weeks until near term. Anatomic anomalies were found in 8.9% of SUA as compared to 4.8% for three-vessel cords. Intrauterine growth restriction (IUGR) was seen in four cases of SUA and none in the control group. EFW and AFI for both groups were virtually identical. CONCLUSION: SUA cords theoretically carry a normal blood volume, and the decreased resistance to flow and larger arterial diameter allow this to occur. Anomalies and IUGR are elevated in infants with SUA. Overall, EFW and AFI were the same in both groups of patients.     

Perinatal audit on avoidable mortality in a Dutch rural region: a retrospective study

OBJECTIVE: To analyse the mode and cause of perinatal mortality. SETTING: a rural Dutch region. STUDY DESIGN: Over a two-year period (1994-1995), data were collected in the 's Hertogenbosch region. A perinatal audit group investigated and classified the cause of death in an "intention to treat" and concensus model. We then analyzed who was responsible for the patient at the moment perinatal death occurred, or became inevitable. RESULTS: Out of 8509 newborns, 73 died between the 24th week of pregnancy till the 7th day post-partum (8.58 promille). Twenty-three cases (31.50%) were classified as probably or possibly avoidable. In the primary health care group (midwives, general practitioners) 6 out of 32 (18.75%), in the secondary care group (obstetricians) 15 out of 35 (44.86%) and in the tertiary care group 1 out of 4 (25.00%) were judged as probably or possibly avoidable. The degree of concensus in the perinatal audit committee was high (Kappa=0.9). IMPACT: The analysis of perinatal mortality identifies the cause of death and may help to improve perinatal health care. CONCLUSION: In this study, 31.55% of perinatal mortality was avoidable in the three levels of care. Intra-uterine growth retardation, congenital malformations and antepartum haemorrhage were the most determinant factors for perinatal mortality. The Dutch obstetrical care system as such, for example home deliveries, did not effect the perinatal mortality rate. Perinatal mortality rates presented by the Dutch Central Bureau of Statistics still shows a slight underregistration.     

Presence of a single fetal major anomaly in a twin pregnancy does not increase the preterm rate

OBJECTIVE: To evaluate whether the presence of one major anomaly in a twin pregnancy would affect the perinatal outcome of the unaffected co-twin. MATERIALS AND METHODS: From 1992 May to July 2003, a total of 1400 twin pregnancies were included in the present study and there were 35 pairs of twins with one major anomaly. Major anomaly was defined as the anomaly that had a significant impact on neonatal morbidity and mortality. The perinatal outcomes of the affected and unaffected co-twins, the gestational age of diagnosis of the anomaly and the gestational age of delivery were the parameters for evaluation. RESULT: The incidence of a twin with one major anomaly was 2.5%. Nineteen of 35 (54.3%) affected twins and five of the 35 (14.3%) unaffected co-twins suffered a perinatal death. In the five cases of unaffected co-twins suffering a perinatal death, four were intrauterine fetal deaths and one was a neonatal death. Three of the perinatal deaths of the unaffected co-twins could be attributed to twin-to-twin transfusion syndrome. The gestational age at delivery, the perinatal mortality rate, and the incidence of low 5 min Apgar scores of the unaffected co-twins were not different from those in twin pregnancies without a major anomaly. CONCLUSION: The perinatal outcomes of the unaffected co-twin were not affected by the fact that its counterpart had one major anomaly, nor were these twin pregnancies at increased risk of preterm labour.     

胎儿单脐动脉临床评估及预后

目的:了解单脐动脉胎儿的转归,围生结局及处理方式。方法:回顾我院近4年170例单脐动脉胎儿的临床资料(经超声、MRI、羊水或脐血染色体检查、引产胎儿尸体解剖结果等),随访出生后婴儿情况并进行临床评估及分析。结果:单脐动脉合并其他结构畸形的发生率为49.3%,合并一种畸形的发生率为15.9%,合并多种畸形发生率为33.3%;单脐动脉胎儿合并染色体异常发生率为18.4%;行MRI检查37例,与超声结果相符29例,8例与超声结果有差异,与超声符合率为78.4%。结论:超声检查易早期诊断单脐动脉,单脐动脉具有胎儿畸形的高风险性。单脐动脉合并其他结构畸形者建议行胎儿染色体检查。超声、染色体检查诊断未发现合并畸形的胎儿出生后仍有异常可能。单脐动脉不是剖宫产指征。     

Perinatal outcomes in singleton pregnancies with a single umbilical artery

Objective: To analyze perinatal outcomes in singleton pregnancies with a single umbilical artery (SUA) as an isolated finding with no other underlying disorders.

Methods: This retrospective observational study compared a group of pregnancies with SUA (n?=?127) and a group with a normal 3-vessel umbilical cord (n?=?27?752). The study variables comprised maternal and obstetric characteristics and perinatal outcomes.

Results: The frequency of SUA was 0.45%. Pregnancies with SUA ended more frequently with cesarean delivery, and had a higher risk that the indication for cesarean delivery was non-reassuring fetal heart rate (NRFHR). Neonates in the SUA group had a lower weight for gestational age, and a higher risk of low umbilical cord blood pH.

Conclusion: Obstetricians should monitor fetal growth closely in pregnancies with SUA, and be alert to NRFHR during labor and delivery.     

Is single umbilical artery an independent risk factor for perinatal mortality?

Objective  

To evaluate perinatal outcome of fetuses with isolated single umbilical artery (SUA), and specifically to examine whether an isolated SUA is an independent risk factor for perinatal mortality.     

Eight years' experience of uterine rupture cases.

Ruptured uterus is a serious obstetric emergency with a high maternal and perinatal mortality. It is a preventable and common obstetric problem in developing countries. The objective of this study was to review the incidence, methods of diagnosis and maternal and perinatal morbidity and mortality associated with uterine rupture. Case notes were reviewed for all patients with a ruptured uterus at Yüzüncü Yil University Medical Faculty Department of Obstetrics and Gynaecology from January 1995 to August 2003. Relevant data relating to the clinical characteristics of labour, operative procedures, maternal and perinatal outcome were assessed. There were 20 cases of ruptured uteri. The incidence was 0.40%. When patients referred from other hospitals were excluded, the revised ratio was 0.12%. There were 13 (65%) complete and seven (35%) incomplete ruptures. Nine (45%) cases occurred in patients with scarred uteri. Ten (50%) cases were grand multiparous. Subtotal abdominal hysterectomy was performed in five (25%) cases, total abdominal hysterectomy was performed in two (10%) cases and the remaining 13 (65%) cases had uterine rupture repair. There were two (10%) maternal deaths. Both of them were referred from other hospitals. There were seven (35%) perinatal deaths attributable to uterine rupture. Occurrence of uterine rupture is significantly associated with grand multiparity, scarred uterus, lack of antenatal care, unsupervised labour at home and low socioeconomic status of the patients. These factors are largely preventable.     

Earlier gestational age at ultrasound evaluation predicts adverse neonatal outcomes in the preterm appropriate-for-gestational-age fetus with idiopathic oligohydramnios

Oligohydramnios is related to adverse perinatal outcomes particularly when associated with fetal growth restriction. The purpose of this study was to delineate predictors of adverse perinatal outcomes in cases of preterm idiopathic oligohydramnios associated with appropriate-for-gestational-age (AGA) fetal biometry. A database of preterm AGA fetuses (< 37 weeks) presenting for evaluation of idiopathic oligohydramnios (defined as an amniotic fluid index [AFI] < 10th percentile) in the third trimester with delivery information and uterine artery Doppler indices (average resistance index [RI] and bilateral notching) available was prospectively collected ( N = 90). AFI and birth weight (BW) percentiles were calculated using standard tables. Chi-square and Student T test were used to evaluate for predictors of adverse perinatal outcomes including BW < or = 10th percentile, stillbirth, neonatal intensive care unit admission, 5-minute Apgar score < 7, preterm delivery < 35 weeks, and preeclampsia. Patients destined to experience poor perinatal outcomes (22%) were demographically similar to those experiencing normal outcomes in terms of maternal age ( P = 0.5), ethnicity ( P = 0.9), body mass index ( P = 0.3), and parity ( P = 0.9). However, at-risk patients were more likely to present with oligohydramnios at an earlier gestational age (GA) than those not at risk (33.0 +/- 3.0 versus 34.4 +/- 2.0 weeks; P = 0.02). There were no differences in perinatal outcomes associated with AFI percentile ( P = 0.9), increased average uterine artery RI ( P = 0.5), bilateral notching ( P = 0.4) or a combination of increased uterine artery RI and bilateral notching ( P = 0.2). Patients with preterm AGA fetuses who present with idiopathic oligohydramnios at an earlier GA are at risk for adverse perinatal outcomes compared with those presenting later in gestation. Sonographic indices, particularly uterine artery Doppler findings, were not found to be useful predictors of adverse outcomes.     

Isolated oligohydramnios is not associated with adverse perinatal outcomes

Objective   To examine fetal growth and perinatal outcomes in pregnancies with isolated oligohydramnios.
Design   A cohort study.
Setting   Multiple clinics and hospitals.
Population   Low risk pregnant women.
Methods   We used data from the multicentre clinical trial of Routine Antenatal Diagnostic Imaging with UltraSound (RADIUS), in which 15,151 low risk pregnant women were randomly assigned to the ultrasound screening group or the control group. Women in the screening group underwent sonographic exams at 15–22 and 31–35 weeks of gestation. Both groups could have clinically indicated sonographic exams at any time.
Main outcome measures   We used changes of fetal weight z -score to assess whether fetal growth was compromised from the diagnosis of oligohydramnios until delivery, using a repeated-measures regression. We used a combined perinatal index as an indicator of adverse perinatal outcome, which consisted of severe perinatal morbidity and mortality.
Results   Oligohydramnios (amniotic fluid index ≤5 cm) was diagnosed in 1.5% (113/7617) of women with ultrasound screening compared with 0.8% (57/7534) among the controls. Approximately half of the oligohydramnios cases in the screening group were isolated with no clearly associated factors (e.g. premature rupture of the fetal membranes, congenital anomalies, diabetes, hypertension, postdate and intrauterine growth restriction). Fetal weight centiles in isolated oligohydramnios cases did not change significantly from diagnosis until delivery. Pregnancies with isolated oligohydramnios had perinatal outcomes similar to pregnancies with a normal amniotic fluid index.
Conclusion   Isolated oligohydramnios is not associated with impaired fetal growth or an increased risk of adverse perinatal outcomes.     

Prenatal diagnosis and management of sacrococcygeal teratoma

Five fetuses, each with a sacrococcygeal teratoma (SCT) were delivered at the Royal Women's Hospital while 2 fetuses, each with a SCT were delivered at Monash Medical Centre in 1998. The number of cases reported in this series is higher than expected but it most likely occurred due to chance. The diagnosis was made prenatally in all cases. Three of the SCT were entirely external while the remaining 4 were external with intrapelvic extension. Rapid growth of the SCT occurred in 3 fetuses. This was associated with polyhydramnios in 2 fetuses. No fetus developed nonimmune hydrops. Six infants were liveborn (perinatal mortality rate of 14%), 3 of whom were delivered prior to 37 weeks' gestation. Two infants were delivered by classical Caesarean section. The remaining 4 infants were delivered by lower uterine segment Caesarean section. There was 1 perinatal death. This stillborn infant was delivered vaginally. The 6 surgical resections were performed between the 4th and 10th postnatal days. Histological examination confirmed the diagnosis of benign SCT in each. One infant developed a recurrence at 2 months of age and required chemotherapy.     

Serial sonographic growth assessment in pregnancies complicated by an isolated single umbilical artery

Pregnancies complicated by an isolated single umbilical artery (SUA) are thought to be at increased risk for intrauterine growth restriction (IUGR). The management of these pregnancies often includes serial sonographic assessments of fetal growth. The goal of our study was to test the validity of this assertion. We conducted a longitudinal sonographic assessment of intrauterine fetal growth in pregnancies complicated by a SUA. We included pregnancies where fetal growth was assessed three or more times, and the presence of SUA was repeatedly demonstrated. Pregnancies with fetal anomalies and multiple gestations were excluded. IUGR was defined as an estimated fetal weight (EFW) < or = 10th percentile of the normal ranges established by Hadlock. Between January 1999 and December 2005, we identified 273 pregnancies with SUA, for an overall incidence of 0.48% within the total population of patients examined at our institution. One hundred and thirty-five pregnancies did not meet our inclusion criteria. Of the 138 we analyzed, four pregnancies (2.9%) were found to have EFW < or = 10th percentile. We concluded that the occurrence of IUGR in pregnancies complicated by an isolated SUA is not increased. Serial sonographic assessments of fetal growth do not appear to be indicated in the management of such pregnancies.     

Diagnosis and management of Rh alloimmunization

OBJECTIVE: To assess the current problem of alloimmunization in a tertiary referral center in Croatia. The results obtained were compared to data published worldwide. METHODS: Retrospective case analysis included women with Rhesus (Rh) alloimmunization treated in our department from January 1997 to January 2003. Data of interest included the incidence, prevention, diagnosis and treatment, with the final point being perinatal mortality and morbidity. RESULTS: 23 pregnant women with alloimmunization were identified. The incidence was 0.138% of deliveries in the same time period. The median gestational age at diagnosis/referral was 22 (range 9-37) weeks. Anti-D antigen, alone or in combination with the other antigens, was responsible for more than 90% of the alloimmunization cases included. A defined protocol for prevention of Rh D immunization after previous delivery was not followed properly in 9/19 cases. A particular problem was prophylaxis after previous pregnancy termination (TOP), whereby only 1/14 woman received adequate prophylaxis and only after 2 of 5 TOPs. Regarding fetal treatment, 9/23 women had a total of 24 intrauterine intravascular blood transfusions. Overall, perinatal mortality was 13%, and the median gestational age at delivery was 34 (range 31-40) weeks. In all there were 31 fetal exchange transfusions after delivery performed in 14/20 newborns. CONCLUSION: Despite precise diagnostic criteria and modern therapeutic options, alloimmunization remains a problem in Croatia. It is still related with a high perinatal mortality and morbidity. The main problem is inadequate prevention.