Objective
The objective of the study was to investigate the effect of umbilical cord milking as compared with early cord clamping on hematological parameters at 6 weeks of age among term and near term neonates.
Study Design
This was a randomized control trial. Eligible neonates (>35 weeks’ gestation) were randomized in intervention and control groups (100 each). Neonates of both groups got early cord clamping (within 30 seconds). The cord of the experimental group was milked after cutting and clamping at 25 cm from the umbilicus, whereas in control group cord was clamped near (2-3 cm) the umbilicus and not milked. Both groups got similar routine care. Unpaired Student t and Fisher exact tests were used for statistical analysis.
Results
Baseline characteristics were comparable in the 2 groups. Mean hemoglobin (Hgb) (11.9 [1.5] g/dL and mean serum ferritin 355.9 [182.6] μg/L) were significantly higher in the intervention group as compared with the control group (10.8 [0.9] g/dL and 177.5 [135.8] μg/L), respectively, at 6 weeks of age. The mean Hgb and hematocrit at 12 hours and 48 hours was significantly higher in intervention group ( P = .0001). The mean blood pressure at 30 minutes, 12 hours, and 48 hours after birth was significantly higher but within normal range. No significant difference was observed in the heart rate, respiratory rate, polycythemia, serum bilirubin, and need of phototherapy in the 2 groups.
Conclusion
Umbilical cord milking is a safe procedure and it improved Hgb and iron status at 6 weeks of life among term and near term neonates.
Anemia is common among children in developing countries. In the National Family Health Survey III of India, 70% of children were anemic. Anemia during infancy and early childhood has been shown to affect cognitive brain function. Delayed cord clamping (DCC), in which the cord is clamped after a short delay after birth, and umbilical cord milking (UCM), in which cord blood is stripped or milked toward the baby, have been shown to prevent anemia in infants.
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These procedures allow the transfer of additional blood volume (and hemoglobin [Hgb]) from the placenta to the newborn infant. This process can improve the infant’s iron stores, which may be of particular value in settings in which nutrition is poor. However, a recent metaanalysis reported that delayed cord clamping is only marginally beneficial in reducing anemia in term neonates. Moreover, there are concerns about delayed initiation of resuscitation and increased incidence of hypothermia among preterm babies undergoing these procedures. Recent studies have demonstrated that UCM and DCC result in comparable increases in Hgb in premature babies. However, there are insufficient data about the effect of UCM in full-term neonates.
The aim of our study was to investigate the effect of umbilical cord milking compared with early cord clamping on hematological parameters at 6 weeks of age among term and near term neonates. We hypothesized that umbilical cord milking will transfer extra blood to the baby that will result in higher Hgb and ferritin in early infancy.
Materials and Methods
This study was designed as a single-center, randomized, controlled trial, conducted from April 2010 to September 2011 in the Departments of Pediatrics and Obstetrics at a teaching hospital in North India. Two investigators (A.U. and S.G.) approached expectant mothers and their spouses (parents), explained the study, and obtained the written consent before the birth of the baby.
We included all infants of more than 34 weeks 6 days of completed gestation, delivered either by low uterine segment transverse cesarean or vaginal delivery at LLRM Medical College Meerut. Only families living in proximity (5 km radius) of the institution were included to increase the follow-up.
Gestational age was determined by first-trimester ultrasonography (USG) or by last menstrual period, if USG was not available. We excluded babies with the following problems: short umbilical cord length (<25 cm), limp at birth, nonvigorous and born through meconium-stained liquor, delivery by cesarean section for fetal compromise, multiple births, delivery to Rh-negative mothers, major congenital anomalies, cord prolapse, hydrops fetalis, placenta previa, placental abruption, and cord abnormalities such as true knots.
Sample size estimation
With early cord clamping (the routine practice at our institution), the mean Hgb at 2 months of age is about 9 (±2) g/dL. To detect a mean increase in Hgb by 1 g/dL in neonates with early cord clamping and umbilical cord milking, with 90% power and 2-tailed alpha value of 0.05, we needed to enroll 85 subjects in each group (total 170 babies). Because blood collection was to be done on healthy babies, we anticipated a dropout rate of 10-15%.We therefore enrolled and randomized 200 newborns.
Randomization and blinding
For randomization, we used computer-generated random numbers in blocks of 4. The blocks were not divided according to gestational age. These numbers were assigned in 2 groups based on whether the random number is odd or even. The methods used included numbers were written on small slips and placed in serially numbered opaque sealed envelopes. Envelopes were opened just after delivery (after ensuring adequate umbilical cord length) by the attending nurse who was not involved in the study. Blinding of the clinicians and investigators was not possible because the neonatal team was routinely present in the delivery room (because every baby was attended by us) as well as because of the nature of the interventions. Obstetricians were requested to cut the umbilical cord after leaving at least 25 cm of umbilical cord from the umbilical stump of baby, as measured by sponge holding forceps (length 24 cm), which was uniformly used for clamping of cord.
Intervention
Procedure of cord milking
A standardized cord-milking technique was used for this study. All resident doctors of the Department of Pediatrics and Obstetrics involved in delivery and newborn resuscitation were trained for technique of cord milking by showing 3 live demonstrations by primary investigators and showing a video available on the Internet, by Tarno Mordi et al.
In all cases after birth, the babies were held at the level of the uterus in vaginal delivery and on the thighs of mother in cesarean section while the umbilical cord was cut and clamped. In the intervention group, the cord was cut at approximately 25 cm of length from umbilical stump within 30 seconds of birth (early clamping). Then the baby was placed under the radiant warmer. The umbilical cord was raised and milked from the cut end toward infant 3 times with speed at 10 cm/sec, which was same as in previous studies, and then clamped 2-3 cm from the umbilical stump.
In the control group, the umbilical cord was clamped early (within 30 seconds) near the umbilicus and cut without doing cord milking. After that the baby received the routine care similar to intervention group. The time to clamping and milking the umbilical cord was measured by wall-mounted quartz clocks available in the delivery at room (labor room or operation theater). According to our local protocol, we used intramuscular oxytocin routinely after delivery in vaginal and intravenous in cesarean delivery.
Maternal data collection
Maternal data and other demographic details were collected from the mother or her clinical notes after obtaining her consent.
Follow-up
The investigators noted telephone numbers of parents of enrolled babies and called weekly to gain confidence and advice about common problems. They were requested to visit for follow up at 6 weeks of age. Three telephonic reminders were made in case any baby failed to show up for a scheduled follow-up visit. Our study staff visited their residence if there was a failure to attend the follow-up after 3 telephonic reminders.
The primary outcome of the study was Hgb and serum ferritin at 6 weeks of postnatal age in term and near term infants. Secondary outcomes were the following: (1) hemodynamic parameters of heart rate, respiratory rate, blood pressure, temperature, and urine output in the first 48 hours; (2) clinical parameters of respiratory distress, jaundice requiring phototherapy, polycythemia, and jitteriness in 48 hours; and (3) hematological parameters of Hgb, packed cell volume at 12 and 48 hours, and bilirubin level at 48 hours.
Statistical analysis
Group means of continuous normally distributed data were compared using an unpaired Student t test. Categorical data were compared using a χ 2 /Fisher exact test, as applicable. The GraphPad software was used for tests, which is freely available on the Internet ( http://www.graphpad.com/quickcalcs/index.cfm ).
Ethical clearance
The study was approved from the Institutional Ethical Committee, LLRM Medical College, Meerut, India. The trial was registered under the Clinical Trial Registry of India (CTRI—registration number was CTRI/2011/09/002011).
Results
Patient characteristics
A total of 700 babies were delivered during the period. Five hundred babies were excluded for different reasons ( Figure 1 ). Two hundred neonates fulfilled the inclusion criteria and were randomized to intervention and control group (100 in each group).
Trial compliance
Flow of participants
Of 200 newborns enrolled, 171 (120 term and 51 near term) completed the trial ( Figure 1 ). The baseline demographic characteristics of the 2 groups were comparable ( Table 1 ).
| Characteristic | Intervention group (n = 100) | Control group (n = 100) | P value |
|---|---|---|---|
| Gestation, wks | 37.3 (1.72) | 37.3 (1.69) | .75 |
| Birthweight, kg | 2.75 (0.41) | 2.64 (0.32) | .92 |
| Sex, male a | 44 (44%) | 34 (34%) | .19 |
| Vaginal delivery a | 56 (56%) | 66 (66%) | .20 |
| Maternal age, 18-40 y a | 90 (90%) | 92 (92%) | .80 |
| Maternal weight, kg | 46.8 (1.1) | 47.2 (0.3) | .68 |
| Maternal Hgb, g/dL | 9.93 (1.33) | 9.55 (1.21) | .19 |
| Maternal anemia, Hgb <9 g/dL a | 54 (54%) | 51 (51%) | .77 |
| Antenatal iron supplements a | 24 (24%) | 28 (28%) | .83 |
| Low socioeconomic status a | 64 (64%) | 61 (61%) | .77 |
| Use of oxytocin a | 100 (100%) | 100 (100%) | 1.00 |
| Exclusive breast-feeding at 6 wks a | 60 (70.5%) | 58 (68%) | 1.00 |
The mean ferritin and mean Hgb at 6 weeks was higher in the intervention group compared with the control group ( P < .05) ( Table 2 ). The 95% confidence interval (CI) of gain in ferritin because of umbilical cord milking was 125.56–231.21μg/L. The 95% CI of gain in Hgb was 0.66–1.42 g/dL ( Figure 2 ) . On subgroup analysis, similar findings were observed in term and near term infants separately.
| Parameters | Overall infants | Term infants | Near term infants | P value for all groups | |||
|---|---|---|---|---|---|---|---|
| Intervention group (n = 100) | Control group (n = 100) | Intervention group (n = 74) | Control group (n = 75) | Intervention group (n = 26) | Control group (n = 25) | ||
| Hgb at 12 h, g/dL | 15.1 (2.5) | 13.5 (2.1) | 15.3 (2.6) | 13.4 (2.3) | 15.1 (2.0) | 13.9 (1.5) | < .05 |
| Hgb at 48 h, g/dL | 11.9 (1.6) | 10.8 (0.9) | 11.7 (1.7) | 10.8 (1.3) | 12.0 (1.3) | 10.9 (1.1) | < .05 |
| PCV at 12 h, n (%) | 45.7 (7.4) | 41.4 (6.6) | 46.2 (7.35) | 41.2 (7.2) | 45.0 (6.8) | 41.6 (4.4) | < .05 |
| PCV at 48 h, n (%) | 41.2 (6.3) | 37.2 (6.0) | 41.7 (7.1) | 36.8 (6.5) | 40.9 (5.8) | 37.9 (3.9) | < .05 |
| Serum bilirubin at 48 h | 7.4 (3.1) | 6.6 (2.3) | 7.2 (3.2) | 6.5 (2.4) | 6.9 (3.1) | 7.1 (1.8) | > .05 |
| Hgb at 6 wks, g/dL | 11.9 (1.5) | 10.8 (0.9) | 11.9 (1.6) | 10.9 (1.0) | 11.6 (1.2) | 10.7 (0.6) | < .05 |
| (n = 85) | (n = 85) | (n = 63) | (n = 65) | (n = 22) | (n = 20) | ||
| Ferritin at 6 wks, μg/L | 355.9 (182.6) | 177.5 (135.8) | 404.7 (252.2) | 188.6 (143.4) | 311.3 (169.7) | 167.5 (132.8) | < .05 |
| (n = 85) | (n = 85) | (n = 63) | (n = 65) | (n = 22) | (n = 20) | ||
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