Umbilical cord clamping practices of U.S. obstetricians

Abstract

BACKGROUND:

Delayed umbilical cord clamping is associated with significant benefits to preterm and term newborns and is recommended for all infants by the World Health Organization and the American College of Obstetricians and Gynecologists (ACOG). Little is known about the cord management practices of U.S. obstetricians.

OBJECTIVE:

The objective of this study was to describe current cord clamping practices by U.S. obstetricians and investigate factors associated with delayed cord clamping.

STUDY DESIGN:

A cross-sectional survey was sent to 500 members of the American College of Obstetricians and Gynecologists. Umbilical cord practices were assessed, and factors related to delaying cord clamping were examined using Chi-square tests and multivariate logistic regression models.

RESULTS:

The overall response rate was 37% with 74% of those opening the email responding. Sixty-seven percent of respondents reported DCC by one minute or more after vaginal births at term. After preterm and near-term vaginal births, 73% and 79% said they waited at least 30 seconds before clamping. The factor most consistently and strongly related to delaying cord clamping in both bivariate and multivariate analyses was having the belief that the timing of clamping was important. Additional analysis revealed that believing the timing was important was positively associated with the physician’s institution having a written policy on the cord clamping.

CONCLUSIONS:

In this study, a majority of respondents reported delaying cord clamping and indicated that employing strategies to implement the full uptake of this practice could be valuable. Findings suggest that institutional policies may influence attitudes on cord clamping.

Keywords

Umbilical cord clamping cord milking delayed cord clamping placental transfusion practice patterns obstetrics provider beliefs hospital policies

Abbreviations

ACOG

American College of Obstetricians and Gynecologists

CARN

Collaborative Ambulatory Research Network

1 Introduction

In 2016, umbilical cord clamping was performed for the nearly 4 million infants born in the United States [1]. Many newborns likely had their cords clamped immediately after delivery as part of routine care. While common, this practice is not supported by current evidence unless a medical indication exists to separate the neonate sooner [2, 3]. Multiple professional organizations now recommend delayed cord clamping for infants of all gestational ages including the American College of Obstetrics and Gynecology (ACOG), the National Institutes for Health and Care Excellence and the World Health Organization [4 –6]. No consensus definition for delayed versus early cord clamping exists and recommendations vary between sources. In general, intervals of one minute or more for term infants and greater than 30 seconds for premature infants are commonly used in studies [2, 3].

The timing of cord clamping is an important component of ensuring adequate placental transfusion of the perinatal blood supply to the newborn [7]. Other factors such as gravity, uterine contractions, lung aeration, spontaneous inspirations, and crying may also impact placental transfusion [8]. Benefits in preterm infants include decreases in intraventricular hemorrhage, fewer transfusions of packed red blood cells and a reduction in necrotizing enterocolitis [3]. Adverse neonatal events are less common in term infants, but research demonstrates a positive association between early cord clamping and infant iron deficiency in the first year of life [9, 10]. Inadequate iron stores during the first twelve months has been associated with both short and long term cognitive, motor and social-behavioral deficits [11 –14]. No adverse maternal outcomes have been found in research on delayed cord clamping [2, 3]. The Cochrane Review on early versus late clamping in term infants found an association between late clamping and treatment for jaundice (RR 0.62, 95% CI 0.41 to 0.96, seven trials, 2324 infants). The clinical implications of this finding appear negligible as there was no association found for the presence of clinical jaundice (RR 0.84, 95% CI 0.66 to 1.07, six trials, 2098 infants) [2].

As new evidence of the benefits of delayed cord clamping emerges, implementation of this evidence into clinical practice is essential. A primary element for implementation is a clear understanding of any current evidence-practice gaps [15]. Research in countries with resources similar to the U.S. shows a wide range of physician use of delayed cord clamping. For example, individual studies report a rate of 8% in Canada [16] and 75% in the Netherlands [17]. We were unable to find any published research on cord clamping practices for the U.S. where physicians currently attend over 90% of births [18].

A survey of ACOG members in 2012 investigated attitudes and beliefs on the timing of umbilical cord clamping [19]. The research was conducted prior to release of the first ACOG Committee Opinion on cord clamping in the same year [19, 20]. Survey participants were members of the Collaborative Ambulatory Research Network (CARN) of ACOG, a national collective of over 1500 board-certified obstetricians–gynecologists (OB/GYN) and maternal fetal medicine specialists (MFM). Findings demonstrated that respondents were more likely to report that the timing of cord clamping was important at earlier gestational ages. Nearly one quarter reported not knowing if it was important. Those who thought it was important also expressed concerns about risks not supported by current evidence. Overall, responses suggested providers were not convinced by the extensive literature on the benefits of delayed cord clamping.

The purpose of our study is to describe current cord clamping practices by obstetricians in the U.S., to investigate factors associated with delaying cord clamping and to examine beliefs about the importance of timing in contrast to previous findings. Our primary hypothesis was that obstetrical providers would be more likely to perform delayed cord clamping for preterm infants than for term infants, given the 2012 ACOG Committee Opinion [20]. Second, we proposed that the presence of an institutional policy that addresses the timing of cord clamping would be positively associated with the practice of delaying clamping.

2 Materials and methods

We conducted a cross-sectional survey of 500 randomly selected participants from the ACOG CARN using the RAND function in Microsoft Excel. Surveys were distributed via email using Magnetmail [21] during April and May 2016. Up to five reminder emails were sent to non-respondents. Approval for this study was obtained from the George Washington University Institutional Review Board.

2.1 Questionnaire

The survey included eight, multiple part questions related to the management of the umbilical cord at birth. The questions were designed to evaluate variation in practice by gestational age, mode of delivery and/or special circumstances such as infant resuscitation, shoulder dystocia, and forceps or vacuum delivery.

Considering the lack of consensus on the optimal timing for waiting to clamp the cord, our operational definition for delayed cord clamping for term births was based on the recommendation by WHO of waiting at least one minute or greater. For preterm births, delayed clamping was defined as at least 30 seconds per the 2012 recommendation from ACOG [6, 20]. Thirty seconds was also used in questions about cord clamping at complicated births. Timing options for term births were broken down into less than one minute, one to three minutes, more than three minutes to five minutes, when the cord stops pulsating, and after delivery of the placenta. For preterm births, additional options of less than 30 seconds and 30 to 59 seconds were added [20]. Questions about cord milking, cord management during resuscitation, institutional policies, and perceived importance of the timing of cord clamping were also included.

2.2 Statistical analysis

Bivariate analyses using the Chi-square test examined which demographic and practice characteristics were related to delaying cord clamping for preterm and term neonates at vaginal and cesarean births. Multivariate logistic regression models were performed to identify characteristics independently related to delayed cord clamping, controlling for other demographic and practice factors.

Based on the discovery that in some models, belief about the importance of the timing of cord clamping was related to delayed cord clamping practice, we conducted supplementary multivariate regression analysis to investigate which characteristics were related to belief that cord clamping timing was “very” or “moderately” important. Data were analyzed using Stata Data Analysis and Statistical Software [22]. Significance was set at p < 0.05.

The response rate was calculated using both traditional methods (# responses/[total N – opt outs]) and the recommended method for response reporting on e-mail surveys from the American Association for Public Opinion Research (AAPOR) (# responses/[# opened emails – opt outs]) [23].

3 Results

There were 179 responses with 17 opt outs. The survey email was opened by 259 recipients. The overall response rate was 37.0% (179/[500-17]). Using the AAPOR guideline for email surveys, the rate was 73.9% (179/259-17). Key data on cord clamping was missing for eight respondents, so our final analytic sample was 171 physicians.

Respondent characteristics are presented in Table 1. There were more female (55.3%) than male (44.7%) respondents, and the average age was 53. The majority were general OB/GYNs (80.6%) with 14.7% subspecialized in MFM.

Table 1
Characteristics of the study sample

Characteristics Percent (n = 171)

Gender

Male 44.7

Female 55.3

Years working in obstetrical practice

0–15 26.6

16–25 37.3

26+ 36.1

Primary medical specialty

General OB/GYN 80.6

Maternal fetal medicine 14.7

Other 4.7

Practice utilizes midwives

Yes 41.5

No 58.5

Location of practice

Urban/suburban 80.0

Rural/town 20.0

Region of practice

Northeast 14.0

South 32.8

West 23.4

Midwest 24.0

Other/not reported 5.9

Importance of timing of cord clamping for term infant

Very/moderately important 32.1

Somewhat Important 27.4

Not important/don’t know 40.5

Reports institutional policy on delayed cord clamping

Yes 28.1

No 61.4

Don’t know 10.5

Characteristics	Percent (n = 171)
Gender
Male	44.7
Female	55.3
Years working in obstetrical practice
0–15	26.6
16–25	37.3
26+	36.1
Primary medical specialty
General OB/GYN	80.6
Maternal fetal medicine	14.7
Other	4.7
Practice utilizes midwives
Yes	41.5
No	58.5
Location of practice
Urban/suburban	80.0
Rural/town	20.0
Region of practice
Northeast	14.0
South	32.8
West	23.4
Midwest	24.0
Other/not reported	5.9
Importance of timing of cord clamping for term infant
Very/moderately important	32.1
Somewhat Important	27.4
Not important/don’t know	40.5
Reports institutional policy on delayed cord clamping
Yes	28.1
No	61.4
Don’t know	10.5

For healthy, term infants after a vaginal birth, approximately two-thirds (67.1%) of respondents reported that they delayed cord clamping by one or more minutes (Table 2). Clamping the cord was delayed by approximately three-quarters of providers at preterm (73.4%) and near-term (79.4%) vaginal births. After a cesarean at term, fewer respondents (35.5%) said they would delay a minute or more.

Table 2

Timing of cord clamping by type of birth and complication

	<30 seconds (%)	30–59 seconds (%)	<1 minute (%)	1–3 minutes (%)	>3–5 minutes (%)	After cord stops pulsating (%)
Healthy term infant, Vaginal birth	–	–	32.9	41.2	9.4	16.5
Healthy term infant, Cesarean section	–	–	64.5	32.5	0.0	3.0
Preterm vaginal birth	26.7	37.6	–	27.9	4.9	3.0
Near-term, vaginal birth	20.5	35.5	–	33.1	4.2	6.6
Infant requiring resuscitation after vaginal birth	89.8	7.2	–	3.0	0.0	0.0
Infant requiring resuscitation after cesarean section	92.9	5.4	–	1.8	0.0	0.0
After a shoulder dystocia	75.2	9.1	–	9.7	1.2	4.9
After forceps or vacuum delivery	44.8	19.0	–	25.2	1.8	9.2

After forceps or vacuum were used, over half of the providers (55.2%) said they waited at least 30 seconds. Few respondents that they indicated delayed clamping for one minute or more when resuscitation was required (3.0% after vaginal births and 1.8% after cesarean births).

Participants in the survey were asked if they used cord milking. The greatest number said they would milk the cord after a preterm (38.6%) or near-term (31.6%) vaginal birth. Less than one quarter indicated it would be performed when an infant requires resuscitation after a vaginal birth (21.6%) or a cesarean (24.0%) (Appendix 1). No relationship was observed between milking practices and delayed cordclamping.

Almost one third (32.1%) reported that that the timing of cord clamping for term infants was “very” or “moderately” important to them (Table 1). Almost as many (28.1%) reported having a policy on the timing of cord clamping at their primary institution. Nearly eight out of ten stated that there were no policies that addressed milking the umbilical cord (79.5%) or resuscitation with the cord intact (79.0%) (not shown).

In bivariate analysis, the factor most consistently and strongly related to delayed cord clamping was provider belief about the importance of the timing of cord clamping (Appendix 2). For example, 94.3% of those who said the timing was “very important” or “moderately important” reported delaying cord clamping for vaginal births at term compared to 73.9% who said it was “somewhat important” and 39.7% who said, “not important” or “don’t know”.

Maternal fetal medicine physicians were significantly more likely to practice delayed cord clamping than general OB/GYNs at both term vaginal births (88.0% compared to 61.8%) and term cesareans (72.0% compared to 28.9%) (Appendix 2). While MFM physicians had higher rates of delayed cord clamping for preterm and near-term births than general OB/GYNs, the rates were not significantly different.

Multivariate regression also showed that belief in the importance of cord clamping timing was highly related to the practice of cord clamping (Table 3). When compared to those who said it was “very important” or “moderately important”, the odds ratios for those saying it was “not important” and “don’t know” were 0.02 for term vaginal birth, 0.04 for term cesarean birth and 0.17 for near term births.

Table 3

Multivariate relationships for delaying cord clamping by respondent characteristics

Characteristics	Delaying cord clamping (1+ Minutes)				Delaying cord clamping (30+ Seconds)
	Term vaginal births		Term c-section births		Preterm vaginal birth		Near-term vaginal birth
	Odds ratio	p-value	Odds Ratio	p-value	Odds Ratio	p-value	Odds Ratio	p-value
Gender
Male	(1.00)		(1.00)		(1.00)		(1.00)
Female	2.56	0.07	3.13	0.02	1.42	0.38	1.60	0.22
Years in obstetrical practice
0–15	(1.00)		(1.00)		(1.00)		(1.00)
16–25	1.78	0.35	1.67	0.39	0.41	0.07	0.90	0.81
26+	4.33	0.03	4.42	0.02	0.84	0.74	1.00	1.00
Primary medical specialty
General OB/GYN	(1.00)		(1.00)		(1.00)		(1.00)
Maternal fetal medicine	3.26	0.14	6.96	<0.01	2.20	0.13	2.25	0.13
Other	8.98	0.07	2.05	0.50	2.16	0.38	1.68	0.55
Practice utilizes midwives
Yes	1.97	0.15	2.66	0.04	1.83	0.11	1.70	0.15
No	(1.00)		(1.00)		(1.00)		(1.00)
Location of practice
Urban/suburban	(1.00)		(1.00)		(1.00)		(1.00)
Rural/town	7.19	<0.01	2.19	0.16	2.16	0.12	2.00	0.14
Region of practice
Northeast	0.32	0.34	0.21	0.15	0.83	0.84	0.62	0.62
South	0.17	0.12	0.18	0.10	0.52	0.46	0.47	0.41
West	0.46	0.50	0.32	0.28	0.86	0.87	0.88	0.89
Midwest	0.22	0.20	0.21	0.14	1.06	0.94	0.63	0.62
Other/not reported	(1.00)		(1.00)		(1.00)		(1.00)
Importance of timing of cord clamping for infants^a
Very/moderately important	(1.00)		(1.00)		(1.00)		(1.00)
Somewhat important	0.19	0.03	0.23	0.01	0.67	0.42	0.57	0.18
Not important/Don’t know	0.02	<0.01	0.04	<0.01	0.41	0.10	0.17	<0.01
Reports institutional policy on delayed cord clamping
Yes	0.87	0.79	1.53	0.40	1.16	0.72	0.65	0.29
No/Don’t know	(1.00)		(1.00)		(1.00)		(1.00)

^aRespondents were separately asked about the importance of timing of cord clamping for term, near-term, and preterm infants. For analyses related to cord clamping for term infants, we used the response to the question on importance for term infants, and similarly matched the analyses for near-term and preterm infants.

For term births, having 26 years or more of experience was also significantly related to delaying cord clamping (OR = 4.3 for vaginal birth and 4.4 for cesarean birth). Women physicians were more likely to delay cord clamping for cesareans at term (OR = 3.1). Maternal fetal medicine specialists had almost 7 times the odds of practicing delayed cord clamping after cesarean births (Table 3).

Since the key factor predicting delayed cord clamping in three of the four multivariate models was the belief that cord clamping timing is important (Table 3), we conducted supplementary regression analyses to examine what factors predicted belief that cord clamping timing was “very” or “moderately” important (Appendix 3). For term vaginal births, the only strong predictor was being an MFM specialist (OR = 4.6) compared to general OB/GYNs. In contrast, for preterm and near-term vaginal births, the key predictor was having an institutional policy that addressed the timing of cord clamping (OR = 2.8 and 3.4 respectively).

4 Discussion

4.1 Principal findings

This study provides important information on the umbilical cord practices of U.S. obstetricians for which previous data is scarce. We found that a majority of providers surveyed reported delaying cord clamping after preterm (73.4% ≥30 seconds), near-term (79.4% ≥30 seconds) and term (67.1% ≥1 minute) vaginal births (Table 2). This suggests that, in this sample, practice is mostly consistent with current evidence and ACOG recommendations [4, 20]. Our hypothesis that obstetrical providers would be more likely to perform delayed cord clamping in preterm infants than in term infants was supported. One explanation for this may be the fact that until 2017, delayed cord clamping was recommended for preterm but not term births not terms births by the ACOG (14).

Immediate cord clamping was the dominant practice for cesarean births at all gestational ages and for births complicated by shoulder dystocia, operative vaginal delivery and births where resuscitation is required. The most recent committee opinion by the ACOG provides guidance on how to delay clamping at cesarean births. In the same document, the timing of cord clamping for shoulder dystocia and operative vaginal delivery is not discussed nor are they listed as an indication for early clamping. Immediate clamping or individualized care is suggested when immediate resuscitation is indicated [4]. In each of these clinical events, logistical issues may explain the lower rate of use. Infant resuscitation with an intact cord has been studied and solutions that allow the newborn to stay at the mother’s side exist [24 –26].

About one third of providers indicated they were milking the cord at preterm (38.6%) and near-term births (31.6%) (Appendix 1). In addition, the practice was utilized at one quarter of births where resuscitation was required and where the infant may be most likely to benefit from the additional transfusion of blood (vaginal birth 21.6%, cesarean birth 24.0%). No significant relationship was found between the practice of delaying cord clamping and milking the cord. While more than a third of those who milk the cord reported delaying cord clamping, a similar percentage who do not milk also delay cordclamping.

The existence of an institutional policy on the timing of clamping the cord was predictive of the belief that it was important and this belief was predictive of the provider practicing delayed cord clamping.

A higher percentage of respondents stated that the timing of cord clamping was very or moderately important than in the 2014 survey of ACOG members. The smallest changes were seen in the belief that it was important for term infants [19]. Since the first survey was conducted prior to the ACOG’s first committee opinion on cord clamping, its release may have been a contributing factor in increasing views that the timing of clamping is important [20].

The differences in beliefs may also be explained, in part, by the different composition of providers who answered the survey. Demographics show that 2.8% of the first survey’s providers were MFMs whereas this study had 14.7% MFMs. We found that being an MFM was significantly related to stating that timing of cord clamping was important. The gender disposition of 55.3% female and 44.7% male is consistent with the make-up of both CARN (56.2%, 43.8%) and overall ACOG membership (53.7%, 46.3%). However, there was greater number of females vs. males responding to this study than in the 2014 study by Jelin et al. (47% vs. 53%) [19]. In our analysis, gender was a significant factor for delaying cord clamping after term cesareans only.

The percent of providers reporting that they had an institutional policy on cord clamping was higher in our survey (28.1% versus 3.5% in 2014) [19]. Similar studies in Norway and the Netherlands showed that over one third of their institutions had policies [27, 28]. This study provides evidence of an important link between written policies, provider beliefs and the practice of delayed cord clamping. Implementation research points to the importance and effectiveness of assessing readiness as well as barriers and facilitators to practice [29]. A qualitative study found that believing the evidence and a personal sense of knowing were among five drivers of change for providers who switched from routine early to delayed clamping [30]. Based on our findings, establishing policies on the timing of cord clamping within institutions and practices may help to increase uptake of this evidence based practice.

4.2 Limitations, strengths, weaknesses

This study is limited by a lower than optimal traditional response rate which can decrease the generalizability of the results. Self-selection (those who responded) may represent a higher interest in the topic of the timing of cord clamping which could be correlated with both practice and beliefs. As such, the results presented here may or may not accurately reflect current practice. Further, members of the ACOG CARN are volunteers for research. Our results cannot be generalized to describe practice of the profession as a whole. A strength of the research was using questions from the 2014 survey which allowed for analysis of a possible change in beliefs and attitudes from one set of respondents to the other.

What the Study Contributes

The study contributes a heretofore unknown picture of how U.S. obstetricians manage the umbilical cord after birth. The significance of provider belief in the importance of the timing of cord clamping in combination with the positive relationship between institutional policies and believing that timing is important represents importance guidance for changing practice. Along with the growing body of research and professional recommendations supporting delayed cord clamping, this research provides new perspectives and strategies for implementation of this evidence-based practice for newborns.

5 Future research

Of issue is the fact that there is no current consensus on the optimum length of time that cord clamping should be delayed to maximize effective placental transfusion to the newborn. One minute or greater is often used to define delayed clamping for term infants, but other sources propose that a full transfusion may take longer [31]. Some experts suggest that using a time-based approach to guide practice may be misguided and oversimplified given that other physiological factors strongly influence the efficacy of placental transfusion [8]. Further research on the exact mechanisms of placental transfusion will be helpful in guiding practice.

Research on barriers and facilitators to the implementation of delayed cord clamping at multiple gestational ages and in a variety of clinical settings and circumstance is recommended. Specifically, further research on supporting sufficient placental transfusion to infants when resuscitation is required is an important next step.

The authors recommend that individual providers, practices and institutions consider developing initiatives to implement delayed cord clamping and cord milking into practice. Steps for implementation of delayed cord clamping have been described [32, 33]. Implementation might include establishing policies on the timing of clamping and milking, education of caregivers and consumers, and training on integrating the practice into existing systems. As with all efforts to improve practice based on evidence, a shift in culture may also be indicated.

Financial support

This research was partially funded by HRSA UA6MC19010-06.

Disclosure statements

The authors have no potential or actual financial interests related to this study.

Footnotes

Appendices

Appendix 3

Multivariate regression results of factors related to belief that cord clamping timing is very or moderately important

Characteristics	Cord clamping timing is very or moderately important
	For term vaginal births		For near-term vaginal births		For preterm vaginal births
	Odds ratio	p-value	Odds ratio	p-value	Odds ratio	p-value
Gender
Male	(1.00)		(1.00)		(1.00)
Female	2.12	0.06	1.76	0.12	1.27	0.55
Years working in obstetrical practice
0–15	(1.00)		(1.00)		(1.00)
16–25	0.82	0.67	0.61	0.28	0.65	0.35
26+	0.64	0.38	0.81	0.66	0.86	0.42
Primary medical specialty
General OB/GYN	(1.00)		(1.00)		(1.00)
Maternal fetal medicine	4.64	0.01	1.16	0.79	1.42	0.53
Other	1.01	1.00	1.10	0.91	1.39	0.72
Practice utilizes midwives
Yes	0.63	0.22	0.67	0.26	1.18	0.64
No	(1.00)		(1.00)		(1.00)
Location of practice
Urban/suburban	(1.00)		(1.00)		(1.00)
Rural/town	1.50	0.37	0.90	0.80	1.02	0.95
Region of practice
Northeast	3.82	0.28	10.46	0.05	1.45	0.68
South	3.49	0.30	11.40	0.04	1.64	0.55
West	3.68	0.28	17.72	0.02	2.58	0.27
Midwest	4.68	0.20	8.74	0.07	1.48	0.64
Other/not reported	(1.00)		(1.00)		(1.00)
Reports institutional policy on
delayed cord clamping
Yes	0.89	0.78	2.82	0.01*	3.36	0.01*
No/don’t know	(1.00)		(1.00)		(1.00)

Acknowledgments

Cora-Ann Mc Elwain.

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