Variables That Influence US Midwife and Physician Management of the Third Stage of Labor

Oxytocin receptor single nucleotide polymorphism predicts atony-related postpartum hemorrhage

BACKGROUND

Postpartum hemorrhage remains a key contributor to overall maternal morbidity in the United States. Current clinical assessment methods used to predict postpartum hemorrhage are unable to prospectively identify about 40% of hemorrhage cases. Oxytocin is a first-line pharmaceutical for preventing and treating postpartum hemorrhage, which acts through oxytocin receptors on uterine myocytes. Existing research indicates that oxytocin function is subject to variation, influenced in part by differences in the DNA sequence within the oxytocin receptor gene. One variant, rs53576, has been shown to be associated with variable responses to exogenous oxytocin when administered during psychological research studies. How this variant may influence myometrial oxytocin response in the setting of third stage labor has not been studied. We tested for differences in the frequency of the oxytocin receptor genotype at rs53576 in relationship to the severity of blood loss among a sample of individuals who experienced vaginal birth.

METHODS

A case-control prospective design was used to enroll 119 postpartum participants who underwent vaginal birth who were at least 37 weeks of gestation. Cases were defined by either a 1000 mL or greater blood loss or instances of heavier bleeding where parturients were given additional uterotonic treatment due to uterine atony. Controls were matched to cases on primiparity and labor induction status. Genotype was measured from a maternal blood sample obtained during the 2^nd postpartum month from 95 participants. Statistical analysis included bivariate tests and generalized linear and Poisson regression modeling.

RESULTS

The distribution of the genotype across the sample of 95 participants was 40% GG (n = 38), 50.5% AG (n = 48) and 9.5% AA (n = 9). Blood loss of 1000 mL or greater occurred at a rate of 7.9% for GG, 12.5% for AG and 55.6% for AA participants (p = 0.005). Multivariable models demonstrated A-carriers (versus GG) had 275.2 mL higher blood loss (95% CI 96.9-453.4, p < 0.01) controlling for parity, intrapartum oxytocin, self-reported ancestry, active management of third stage or genital tract lacerations. Furthermore, A-carrier individuals had a 79% higher risk for needing at least one second-line treatment (RR = 1.79, 95% CI = 1.08-2.95) controlling for covariates. Interaction models revealed that A-carriers who required no oxytocin for labor stimulation experienced 371.4 mL greater blood loss (95% CI 196.6-546.2 mL).

CONCLUSIONS

We provide evidence of a risk allele in the oxytocin receptor gene that may be involved in the development of postpartum hemorrhage among participants undergoing vaginal birth, particularly among those with fewer risk factors. The findings, if reproducible, could be useful in studying pharmacogenomic strategies for predicting, preventing or treating postpartum hemorrhage.

Umbilical cord clamping and management of the third stage of labor: A telephone-survey describing Swedish midwives’ clinical practice

INTRODUCTION

The timing of cord clamping impacts children’s short- and long-term well-being. When making clinical decisions, midwives incorporate their tacit and professional knowledge, experience and current evidence. There appears to be a lack of knowledge regarding Swedish midwives’ management of the third stage of labor and cord clamping practice. The aim of this study was to explore Swedish midwives’ clinical practice concerning umbilical cord clamping and the third stage of labor in spontaneous vaginal births.

METHODS

The study was designed as a cross-sectional telephone survey including 13 questions. Midwives were randomly selected from 48 births units in Sweden. Two midwives from each unit were interviewed. The primary outcome was timing of umbilical cord clamping practice in full-term infants. Secondary outcomes were the management of the third stage of labor including prophylactic use of synthetic oxytocin, the timing of cord clamping in preterm infants, controlled cord traction, uterine massage, and cord milking.

RESULTS

Altogether, 95 midwives were interviewed. In full-term infants, all midwives preferred late cord clamping. Considerable heterogeneity was seen regarding the practices of synthetic oxytocin administration postpartum, controlled cord traction, uterine massage or cord milking, and cord clamping in preterm infants.

CONCLUSIONS

Midwives in Sweden modify recommendations regarding delayed cord clamping in a way they might perceive as more natural and practical in their daily, clinical work. The study revealed a reluctance toward the administration of prophylactic oxytocin due to fear that the drug could pass to the infant. An overall large variation of the management of the third stage of labor was seen.

Factors affecting third-stage management and postpartum hemorrhage in planned midwife-led home and birth center births in the United States

BACKGROUND

Postpartum hemorrhage (PPH) is a potential childbirth complication. Little is known about how third-stage labor is managed by midwives in the United States, including use of uterotonic medication during community birth. Access to uterotonic medication may vary based on credentials of the midwife or state regulations governing midwifery.

METHODS

Using data from the Midwives of North America 2.0 database (2004-2009), we describe the PPH incidence for women giving birth in the community, their demographic and clinical characteristics, and methods used by midwives to address PPH. We also examined PPH rates by midwifery credentials and by the presence of regulations for legal midwifery practice.

RESULTS

Of the 17 836 vaginal births, 15.9% had blood loss of over 500 mL and 3.3% had 1000 mL or greater blood loss. Midwives used pharmaceuticals to prevent or treat postpartum bleeding in 6.3% and 13.9% of births, respectively, and the rate of hospital transfer after birth was 1.4% (n = 247). In adjusted analyses, PPH was less likely when births occurred at home vs a birth center, if the midwife had a CNM/CM credential vs a CPM/LM/LDM credential, or if the woman was multiparous without a history of PPH or prior cesarean birth. PPH was more likely in states with barriers to midwifery practice compared with regulated states (OR: 1.26; 95% CI, 1.16-1.38).

CONCLUSIONS

Women giving birth in the community experienced low overall incidence of PPH-related hospital transfer. However, the occurrence of PPH itself would likely be reduced with improved legal access to uterotonic medication.

Variability of Clinical Practice in the Third Stage of Labour in Spain

Clinical practice guidelines recommend the active management of the third stage of labour, but it is currently unknown what practices professionals actually perform. Therefore, the aim of this study was to determine the variability of professional practices in the management of the third stage of labour and to identify any associated professional and work environment factors. A nationwide cross-sectional study was performed with 1054 obstetrics professionals between September and November 2018 in Spain. A self-designed questionnaire was administered online. The crude odds ratios (OR) and adjusted odds ratios (ORa) were estimated using binary logistic regression. The main outcome measures were included in the clinical management of the third stage of labour and they were: type of management, drugs, doses, routes of administration, and waiting times used. The results showed that 75.3% (783) of the professionals used uterotonic agents for delivery. Oxytocin was the most commonly administered drug. Professionals who attend home births were less likely to use uterotonics (ORa: 0.23; 95% confidence interval (CI): 0.12-0.47), while those who completed their training after 2007 (ORa: 1.57 (95% CI: 1.13-2.18) and worked in a hospital that attended >4000 births per year (ORa: 7.95 CI: 4.02-15.72) were more likely to use them. Statistically significant differences were also observed between midwives and gynaecologists as for the clinical management of this stage of labour (p < 0.005). These findings could suggest that there is clinical variability among obstetrics professionals regarding the management of delivery. Part of this variability can be attributed to professional and work environment factors.