International Journal of Infertility and Fetal Medicine
Volume 13 | Issue 3 | Year 2022

Management of Rh-negative Alloimmunized Pregnancy Optimizing Perinatal Mortality and Morbidity: A Single-center Study

Devendra Arora1, Madhusudan Dey2, Sanjay Singh3, Abhijeet Kumar4, Vinod G Nair5

1-4Department of Obstetrics and Gynecology, Base Hospital, New Delhi, India

5Department of Obstetrics and Gynecology, Army College of Medical Sciences, New Delhi, India

Corresponding Author: Abhijeet Kumar, Department of Obstetrics and Gynecology, Base Hospital, New Delhi, India, Phone: +91 7219656930, e-mail:

Received on: 07 June 2021; Accepted on: 04 May 2022; Published on: 28 December 2022


Objective: The aim of the study was to report pregnancy and fetal outcomes of Rhesus (Rh)-negative pregnancy at a tertiary care teaching hospital.

Materials and methods: Prospective observational study was carried out on all Rh-negative women over 3 years period. On the basis of the evolution of indirect Coombs test (ICT), titer and middle cerebral artery peak systolic velocity (MCA-PSV) value, women were categorized into five groups. In the group with ICT >1:32 and MCA-PSV >1.5, multiple of median (MOM) or any features of hydrops underwent intrauterine transfusion (IUT). Pregnancy outcomes, neonatal outcomes, and procedure-related adverse events were analyzed.

Results: A total of 496 women were recruited, out of which 411 were non-alloimmunized, and 85 were alloimmunized. Out of 85 alloimmunized pregnancies, 47 fetuses underwent 148 IUT. The overall perinatal mortality was 1/47, while adverse procedure-related complication was nil in fetuses who underwent IUT. In the IUT group without hydropic fetuses, there was no mortality, but 100% of newborns underwent phototherapy, and 30% underwent exchange transfusion, which was better than the previous studies. In the IUT group with hydropic fetuses, one fetus had mortality out of seven has a cumulative perinatal loss rate of 14%. The procedure-related complication rate was 4.7%.

Conclusion: In the absence of fetal hydrops, IUT has a good prognosis with 100% fetus survival in our center. Advancement in neonatal management [concomitant use of phototherapy and intravenous immunoglobulin (IVIG)] of IUT-received fetuses has significantly reduced morbidity related to hemolytic disease of the fetus and newborn (HDFN). Early detection of pregnancy at risk of fetal anemia using ICT titer and MCA-PSV trend and timely management of fetus at risk of anemia using IUT at fetal medicine center leads to a favorable outcome.

How to cite this article: Arora D, Dey M, Singh S, et al. Management of Rh-negative Alloimmunized Pregnancy Optimizing Perinatal Mortality and Morbidity: A Single-center Study. Int J Infertil Fetal Med 2022;13(3):111-115.

Source of support: Nil

Conflict of interest: None

Keywords: Exchange transfusion, Fetal anemia, Indirect Coombs test, Intrauterine transfusion, Perinatal mortality, Rhesus isoimmunization.


Traditionally, women with Rh-negative blood group have poor neonatal morbidity and mortality. The major contributor has been HDFN. HDFN is caused by maternal alloimmunization (antibodies are produced by the mother in response to antigenic stimulation of fetal red cell entering the maternal circulation), inherited from the father, transplacental passage IgG antibody leads to hemolysis in the fetus, which in turn leads to fetal anemia. Untreated, progressing fetal anemia may result in the collection of fluid in the serous cavity namely liver, abdomen, and lung, and cardiac decompensation eventually leads to fetal hydrops [as the presence of >2 abnormal fluid collections in the fetus such as ascites, pleural effusions, pericardial effusion, and generalized skin edema (defined as skin thickness >5 mm)] and perinatal death. If the fetus survives in utero and is delivered, the ongoing hemolysis and fetal liver immaturity lead to hyperbilirubinemia of variable degrees (a severe form of neonatal hyperbilirubinemia and brain injury, as kernicterus), fetal anemia, and death.1 Primarily, anti-Rh(D) type antibodies are associated with severe HDFN, while anti-Kell (anti-K1) or anti-Rh(c) antibodies are associated infrequently. Severe HDFN is occasionally caused by other Rh-antibodies and only very rarely by non-Rh antibodies (Duffy, Kidd, or S). Rh D-negative phenotype is the most common in individuals of European and North American descent (15–17%), while the prevalence in the regions of Africa and India (3–8%) and lowest in Asia (0.1–0.3%).2 Prevalence Rh(D) negative in the Indian population is 5%. The incidence of the disease, however, is now on the decline worldwide, from 1.3–1.7% in the 1980s to 0.17% in the 1990s. The incidence of Rh incompatibility in Rh-negative women carrying an Rh-positive fetus is about 10% of all Rh-negative pregnancies. Sensitization, however, occurs only in about 5% of these cases, giving an incidence of 6–7/1000 of all the pregnancies and one in 15 Rh-negative pregnancies. Today, Rh IG prophylaxis has markedly decreased the prevalence to 0.14–0.2%.3,4 Failure of Rh immunoprophylaxis is a cumulative cascade of inadequate use of Rh immunoprophylaxis after potential sensitizing events and administration of an inadequate dose. Validation of MCA-PSV for detection of fetal anemia and the need for fetal blood sampling (FBS) for IUT if MCA-PSV >1.5 MOM for gestational age (GA) has made serial amniocentesis for fetal anemia screening obsolete.5,6 Evolution of FBS IUT and neonatal care techniques have resulted in close to 90% survival of anemic fetuses, with very good long-term neurodevelopmental outcomes, as per the long-term follow-up after intrauterine transfusion (LOTUS) study. The rarity of this condition and its complexity involved the treatment of these patients at a maternal-fetal medicine center with a neonatal intensive care facility.


The prospective cohort observational study was carried out over a period of 3 years (1st January 2017–31st December 2019) at the Maternal-fetal Medicine Center, Base Hospital, New Delhi, India. The study was approved by the Ethical Review Committee of Army College of Medical Sciences, New Delhi, India. Written informed consent was obtained from all participants, and informed consent for the use of data was also taken. The study was conducted according to the International Conference of Harmonization/Good Clinical Practice guidelines and the latest version of the Helsinki Declaration by World Medical Association. All Rh-negative pregnant women were recruited for this study. A detailed history was taken regarding gravidity, parity, abortion, D&C following abortion, and history of blood transfusion were noted. In addition, any history of stillbirth, fetal anemia in a previous pregnancy, and any history of neonatal jaundice in previous children and if the present type of treatment if required and the outcome of such a neonate. Patients with other minor antigens, such as Kell and M were not recruited in the study. After the confirmation of pregnancy and on the evolution of ICT titer (repeated monthly as long as it remains stable and with rising titers, it was repeated every 2 weeks until the titer reaches the “critical” level), women were divided into the following groups:

In group D, once MCA-PSV was >1.5 MOM using Mari et al. 2000 chart, fetal severe anemia was anticipated and was transfused with fresh (within 5 days) O negative blood, leukodepleted, irradiated with high hematocrit (Hct) (about 80%). IUT was performed under aseptic conditions, guided by continuous ultrasound/Doppler, using a 20–22 gauge needle.7 Further transfusion in this subset was guided by MCA-PSV or rate of fall of hematocrit of 1% per day. Mandelbrot’s formula for intravascular transfusion [intravascular volume = (1.046 + estimated fetal weight (EFW) × 0.14) × (Hct target − Hct initial)/Hct transfused] was used to calculate volume of blood to be transfused. In hydropic fetuses, the target Hct was 25% or maximum up to the four-fold rise of pre-IUT hemoglobin (Hb)/Hct, and if necessary second IUT was performed within 1–2 days to reach the target Hb/Hct. After 35 weeks of POG, no patient received IUT. After IUT fetuses were followed with weekly MCA-PSV and ultrasound for any evidence of hydrops. Indication of delivery after 35 weeks POG was based on the rate of fall of hematocrit as the false positive value of MCA-PSV increases after 35 weeks and usually after 2 weeks of last IUT or if there is any other obstetric indication of delivery. After delivery, cord blood was sent for ABO/Rh typing, Hb%, reticulocyte count, serum bilirubin (total, direct, and indirect), KB test for % of the fetal cell, and direct CT to know the neonatal status. The baby was thoroughly examined for any obvious congenital anomaly and weight, sex, and condition were noted, particularly for any evidence of hydrops. If the neonate was Rh-positive and direct Coombs test (DCT) negative, then the pregnancy was considered nonimmunized and was given postpartum immunoprophylaxis within 24 hours of delivery. If the neonate was Rh-positive and DCT positive, it was considered alloimmunized pregnancy and was not given postpartum prophylaxis. The newborns were observed for the development of jaundice. For our study purpose, we evaluated newborns who received IUT and after birth were given double surface phototherapy and IVIG (1 mg/kg). Exchange transfusion and top transfusion were reserved on case to case basis. The newborns were followed up to 6 months of age.


Statistical analysis of the recruitment of pregnant women for the study is displayed in Flowchart 1.

Flowchart 1: Patient selection work

During the study period total of 496 Rh-negative patients were enrolled, of which 85 patients were isoimmunized. Of this isoimmunized cohort, 47 women received 148 IUT. There were seven (12.7%) hydropic fetuses and 48 (87.7%) fetuses without any features of hydrops. There was a mean of three IUT per pregnancy, with a range of 1–6. The mean maternal age at first IUT was 28.2 years, with a range of 26–34 years. The average GA at first IUT was 28 weeks, with a range of 18–35 weeks shown in Figure 1. Earliest IUT was given at 18 + 3 POG. Trends of average Hb before and after first (6.1 and 12.1), second (8.6 and 13.8), and third IUT (10.3 and 15.1) are shown in brackets. Out of 148 IUT, 132 were done at the placental cord insertion site, 15 in the free loop, and one intrahepatic portion of the umbilical vein.

Fig. 1: Relationship between IUT and GA (weeks)

Maternal characteristic is shown in Table 1.

Table 1: Maternal characteristics of Rh-negative women
Characteristics Group A Group B Group C Group D Group E
Age 26.4 27 28.4 29.4 29.6
BMI 21.8 22 22.3 22.6 23
Parity 2.1 2.1 2.3 2.6 2.6
Average GA of diagnosing hydrops (weeks) 0 0 0 0 26.8
H/o anti-D received 45% 50% 52% 25% 17%
ICT status Negative Positive 1:1–1:64 1:16–1:1024 1:32–1:1024

Pregnancy outcome (Table 2) is almost similar in group A (Rh non-alloimmunized group) and in group B (alloimmunized pregnancy with ICT titer less than critical titer). Mean GA at delivery in the IUT group was 35 + 6 POG while in the hydropic group was 34 + 1. Adverse pregnancy outcome was observed in group E (cohort with fetal hydrops).

Table 2: Pregnancy outcome in Rh-negative women (GA)
Number of women Mean GA at delivery GA <34 weeks GA >34 weeks Mean birth weight in kg IUD after 28 weeks
Group A 411 38 + 2 6 (1.4%) 407 (98.6) 3.26 1
Group B 30 37 + 3 1 (3.4%) 29 (96.6) 3.18 0
Group C 7 37 + 2 0 (0%) 7 (100%) 3.03 0
Group D 40 35 + 6 4 (11%) 36 (89%) 2.7 0
Group E 8 34 + 1 5 (71%) 2 (29%) 1.8 1

Neonatal outcome in Rh-negative pregnancy is shown in Table 3. In group D, there was no perinatal mortality, while in group E, 1/7 neonate died; overall perinatal mortality in IUT fetuses was 2%. Of all fetuses who received IUT, 100% received double surface phototherapy and IVIG. Only 25% of newborns in group D received exchange transfusion, while in group E 42% of newborns required it. There was no fetal and neonatal death in group D, however, there was one neonatal death in hydropic group E due to sepsis and prematurity.

Table 3: Neonatal outcome in Rh-negative women (Hb)
No. of fetuses Mean Hb after birth % of liveborn % phototherapy Exchange transfusion Postdelivery cord Hb (mg%) IVIG Live neonate at 3 months of age ND delay at 6 months
Group A 410 16.4 410 (100%) 25 (6.1%) 0 15.5 0 410 No
Group B 30 16.8 30 (100%) 2 (6.6%) 0 15.4 0 30 No
Group C 8 15.8 8 (100%) 1 (14.2%) 0 15.4 0 30 No
Group D 40 15.5 40 (100%) 40 (100%) 10 (25%) 11.2 40 (100%) 40 No
Group E 7 10.1 6 (72%) 6 (100%) 3 (42%) 8.7 6 (100%) 7 No

There was no procedure-related severe adverse event (Table 4) in fetuses who underwent IUT and only mild adverse event of 6/148 and 4%. There was no neurodevelopmental delay observed in a newborn who were followed up to 6 months of age.

Table 4: Procedure-related adverse event in IUT group, n = 148, 4.7%
Mild adverse event (hemorrhage for more than 1 minute from the puncture site, intraoperative bradycardia, pain, supine hypotension, and uterine contraction) 6/148 <0.001
Moderate adverse event (nonreassuring FHR pattern) 1/148 <0.001
Severe adverse event (cesarean section within 24 hours of IUT and preterm delivery within 7 days of IUT) 0/148 <0.001


This comprehensive study on 498 Rh-negative pregnant women clearly demonstrated that in alloimmunized group, ICT titer clearly discriminates the subset of women who will develop fetal anemia, and the use of IUT will decrease the poor pregnancy outcome and neonatal morbidity and mortality in the specified subset. In the cohort in which ICT titer was more than critical titer and MCA-PSV, >1.5 MOM fetuses underwent IUT. In our study, 47 fetuses underwent a total of 148 IUT. The overall perinatal mortality was 1/47 and 2%, while procedure-related complication rate was 2%. The study by Somerset et al. described a cohort of n = 221 IUTs and reported a perinatal loss rate of 4.7% and procedure-related complication rate of 7.6% (bradycardia, ruptured membranes, and chorioamnionitis).8 While another study in 2011 by Tiblad et al., described a cohort of n = 284 IUTs with a perinatal loss rate of 1.4% and procedure-related complication of 4.9% (bradycardia and needling problems).9 Recent study in 2016 by Pasman et al. reported a cohort of n = 135 and no perinatal loss with procedure-related complication rate of 5.7%.10 In the group of the fetus without any feature of hydrops and who required IUT, there was no mortality, 100% of newborns underwent double surface phototherapy (DSP) and received IVIG, and only 25% of fetuses required exchange transfusion, which was better than previous studies where the requirement of exchange transfusion was in the range of 50–88% (9, 10, and 11). Statistically, p < 0.001 further adds strength to our study.

Recruitment of women early in pregnancy <14 weeks, serial monitoring for fetal anemia by ICT titer and MCA-PSV, IUT at the placental cord insertion site, delivery after 35 weeks POG and at a final intervention concomitant use of double surface phototherapy and IVIG leading to the reduced need of exchange transfusion which in turn reduces mortality and morbidity related to exchange transfusion procedure has led to zero mortality and low morbidity in group D. In cases of IUT done after 28 weeks, the fetuses were observed for 30 minutes by cardiotocography; if persistent nonreassuring fetal heart rate (FHR) pattern persisted plan for emergency cesarean section was made, but in our cohort there was only one case with nonreassuring FHR pattern, which subsided within 10 minutes of observation. The most common symptom of a procedure-related complication was bradycardia at or immediately after the procedure. In many of these instances, it can be suspected that the umbilical arteries were punctured by accident rather than the vein leading to arterial vasoconstriction and severe bradycardia, or that accidental perforation of the vessel occurred with extravasation of blood as a result. There were three cases of intraoperative bradycardia, all were when the free loop of the cord was used for IUT, which too resolved with conservative management, and in one case, we used intravenous atropine 0.01 kg/mg EFW single dose. None of the IUTs with intrahepatic route had bradycardia. In our cohort, there was no case of preterm premature rupture of membrane.

Our cohort with hydropic fetuses, that is, group E has a perinatal loss rate of 12.5% with procedure-related complication rate of 6.4%. In a study by Deka et al. in 2010 with 102 cases with 303 transfusions, the perinatal loss was 1.65%.11 However, the difficult group to treat was women who presented to us with fetal hydrops. The mean GA at delivery was 34 + 1, % of liveborn was 87.5%, and 100% of the babies were given phototherapy and IVIG. The logistic regression model clearly demonstrates that fetal hydrops remains an independent factor for fetal survival. In this group, 42% of neonates required exchange transfusion. Hydrops is the main factor for the poor perinatal outcome and procedure-related risk in a multivariate analysis.


In the absence of fetal hydrops, IUT has a good prognosis with 100% fetus survival in our center. In the subgroup with ICT titer more than critical value MCA-PSV is an excellent tool to guide the need of IUT and further follow-up. However, determination of the need for second and subsequent IUT rate of fall for hematocrit is a better tool than MCA-PSV monitoring. However, fetus who presented with hydrops or developed hydrops during follow-up remains a challenging group with perinatal mortality and morbidity and adverse events associated with procedure-related complication. Hence early detection of Rh immunization, preferably before 14 weeks, and referral to a fetal medicine center early will lead to early detection of fetal anemia and intervention before it progresses to fetal hydrops, in turn, avoiding the perinatal loss and procedure-related complication rate. Further strict implementation of antenatal and postnatal anti-D prophylaxis will reduce the burden of alloimmunized pregnancy. To sum up, early detection of immunized pregnancy, its follow-up with ICT titer and MCA-PSV, use of IUT by an experienced hand, avoiding preterm delivery, and last but not least concomitant use of phototherapy and IVIG will optimize the outcome in a fetus affected with alloimmunization.


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