Complicated third stage of labor: time to switch on the scanner

The association between history of retained placenta and success rate of misoprostol treatment for early pregnancy failure

BACKGROUND

To date, the association between retained placenta and treatment success rate of misoprostol for early pregnancy failure has yet to be evaluated. The aim of this study was to evaluate this association and further investigated the connection between medical, clinical and sonographic parameters and treatment success.

METHODS

We conducted a retrospective cohort study of women with early pregnancy failure treated with misoprostol from 2006 to 2021. The success rate of misoprostol treatment was compared between patients with history of retained placenta including women who underwent manual lysis of the placenta following delivery or patients who were found to have retained products of conception during their post-partum period (study group) and patients without such history (controls). Demographic, clinical, and sonographic characteristics as well as treatment outcomes were compared between the groups.

RESULTS

A total of 271 women were included in the study (34 women in the study group compared to 237 women in the control group). Two-hundred and thirty-three women (86.0%) presented with missed abortion, and 38 (14.0%) with blighted ovum. Success rates of misoprostol treatment were 61.8% and 78.5% for the study and control groups, respectively (p = 0.032). Univariate analysis performed comparing successful vs. failed misoprostol treatment showed advanced age, gravidity, parity and gestational sac size (mm) on TVUS were associated with higher misoprostol treatment failure rate. Following a multivariate logistic regression model these variables did not reach statistical significance.

CONCLUSION

Women who have an event of retained placenta following childbirth appear to have decreased success rate of treatment with misoprostol for early pregnancy failure. Larger studies are needed to confirm this finding.

Risk Factors for Postpartum Hemorrhage in a Thai-Myanmar Border Community Hospital: A Nested Case-Control Study

Postpartum hemorrhage (PPH) is a common complication of pregnancy and a global public health concern. Even though PPH risk factors were extensively studied and reported in literature, almost all studies were conducted in non-Asian countries or tertiary care centers. Our study aimed to explore relevant risk factors for PPH among pregnant women who underwent transvaginal delivery at a Thai–Myanmar border community hospital in Northern Thailand. An exploratory nested case-control study was conducted to explore risk factors for PPH. Women who delivered transvaginal births at Maesai hospital from 2014 to 2018 were included. Two PPH definitions were used, which were ≥ 500 mL and 1000 mL of estimated blood loss within 24 h after delivery. Multivariable conditional logistic regression was used to identify significant risk factors for PPH and severe PPH. Of 4774 women with vaginal births, there were 265 (5.55%) PPH cases. Eight factors were identified as independent predictors for PPH and severe PPH: elderly pregnancy, minority groups, nulliparous, previous PPH history, BMI ≥ 35 kg/m², requiring manual removal of placenta, labor augmentation, and fetal weight > 4000 gm. Apart from clinical factors, particular attention should be given to pregnant women who were minority groups as PPH risk significantly increased in this population.

The increasing role of a retained placenta in postpartum blood loss: a cohort study

PURPOSE

To describe the association between quantity of blood loss, duration of the third stage of labour, retained placenta and other risk factors, and to describe the role of a retained placenta depending on the cutoff used to define postpartum haemorrhage.

METHODS

Cohort study of all vaginal deliveries at two Danish maternity units between 1 January 2009 and 31 December 2013 (n = 43,357), univariate and multivariate linear regression statistical analyses.

RESULTS

A retained placenta was shown to be a strong predictor of quantity of blood loss and duration of the third stage of labour a weak predictor of quantity of blood loss. The predictive power of the third stage of labour was further reduced in the multivariate analysis when including retained placenta in the model. There was an increase in the role of a retained placenta depending on the cutoff used to define postpartum haemorrhage, increasing from 12% in cases of blood loss ≥ 500 ml to 53% in cases of blood loss ≥ 2000 ml CONCLUSION: The predictive power of duration of the third stage of labour in regard to postpartum blood loss was diminished by the influence of a retained placenta. A retained placenta was, furthermore, present in the majority of most severe cases.

Failed manual removal of the placenta after vaginal delivery

PURPOSE

A retained placenta after vaginal delivery where manual removal of placenta fails is a clinical challenge. We present six cases that illustrate the heterogeneity of the condition and discuss the etiology and terminology as well as the clinical management.

METHODS

Members of the European Working group on Abnormally Invasive Placenta (EW-AIP) were invited to report all recent cases of retained placenta that were not antenatally suspected to be abnormally adherent or invasive, but could not be removed manually despite several attempts.

RESULTS

The six cases from Denmark, The Netherlands and the UK provide examples of various treatment strategies such as ultrasound-guided vaginal removal, removal of the placenta through a hysterotomy and just leaving the placenta in situ. The placentas were all retained, but it was only possible to diagnose abnormal invasion in the one case, which had a histopathological diagnosis of increta. Based on these cases we present a flow chart to aid clinical management for future cases.

CONCLUSION

We need properly defined stringent terminology for the different types of retained placenta, as well as improved tools to predict and diagnose both abnormally invasive and abnormally adherent placenta. Clinicians need to be aware of the options available to them when confronted by the rare case of a retained placenta that cannot be removed manually in a hemodynamically stable patient.

Underlying mechanisms of retained placenta: Evidence from a population based cohort study

OBJECTIVE

To determine risk factors for retained placenta, and to identify supporting epidemiologic evidence for the three previously-proposed mechanisms: (i) invasive placentation, (ii) placental hypo-perfusion, and (iii) inadequate uterine contractility.

DESIGN

A retrospective population-based cohort study.

SETTING AND POPULATION

Israeli population in the southern district.

METHODS

Data were analyzed from a tertiary hospital database, between 1989 and 2014, using univariate tests and generalized estimating equation (GEE) multivariable models.

MAIN OUTCOME MEASURES

Prevalence of retained placenta.

RESULTS

The study population included 205,522 vaginal deliveries of which 4.8% (n=9870) were complicated with retained placenta. Previous intra-uterine procedures and placenta-related pregnancy complications were found to be significant risk factors for retained placenta (history of cesarean section aOR=8.82, 95%CI 8.35-9.31; history of curettage aOR=12.80, 95%CI 10.57-15.50; pre-eclampsia aOR=1.25, 95%CI 1.14-1.38; delivery of a small for gestational age neonate aOR=1.08, 95%CI 1.01-1.16; stillbirth aOR=2.34, 95%CI 1.98-2.77). During labour, the risk for retained placenta was increased in presence of arrest of dilatation (aOR=2.03, 95%CI 1.08-3.82) or arrest of descent (aOR=1.55, 95%CI 1.22-1.96). Infections of the uterine cavity during labour were also found to be strongly associated with increased risk of retained placenta (endometritis aOR=2.21, 95%CI 1.64-2.97; chorioamnionitis aOR=3.35, 95% CI 2.78-4.04).

CONCLUSIONS

Supporting epidemiologic evidence were found for all three underlying mechanisms. In addition, there is evidence to suggest that intrauterine infection and inflammation may also be a possible pathology associated with retained placenta.

TWEETABLE ABSTRACT

Risk factors for retained placenta support previously proposed mechanisms in a large cohort study.

Retained placenta: will medical treatment ever be possible?

The standard treatment for retained placenta is manual removal whatever its subtype (adherens, trapped or partial accreta). Although medical treatment should reduce the risk of anesthetic and surgical complications, they have not been found to be effective. This may be due to the contrasting uterotonic needs of the different underlying pathologies. In placenta adherens, oxytocics have been used to contract the retro‐placental myometrium. However, if injected locally through the umbilical vein, they bypass the myometrium and perfuse directly into the venous system. Intravenous injection is an alternative but exacerbates a trapped placenta. Conversely, for trapped placentas, a relaxant could help by resolving cervical constriction, but would worsen the situation for placenta adherens. This confusion over medical treatment will continue unless we can find a way to diagnose the underlying pathology. This will allow us to stop treating the retained placenta as a single entity and to deliver targeted treatments.

Dynamic Changes in the Myometrium during the Third Stage of Labor, Evaluated Using Two-Dimensional Ultrasound, in Women with Normal and Abnormal Third Stage of Labor and in Women with Obstetric Complications

OBJECTIVE

To investigate dynamic changes in myometrial thickness during the third stage of labor.

METHODS

Myometrial thickness was measured using ultrasound at one-minute time intervals during the third stage of labor in the mid-region of the upper and lower uterine segments in 151 patients including: women with a long third stage of labor (n = 30), postpartum hemorrhage (n = 4), preterm delivery (n = 7) and clinical chorioamnionitis (n = 4). Differences between myometrial thickness of the uterine segments and as a function of time were evaluated.

RESULTS

There was a significant linear increase in the mean myometrial thickness of the upper uterine segments, as well as a significant linear decrease in the mean myometrial thickness of the lower uterine segments until the expulsion of the placenta (p < 0.001). The ratio of the measurements of the upper to the lower uterine segments increased significantly as a function of time (p < 0.0001). In women with postpartum hemorrhage, preterm delivery, and clinical chorioamnionitis, an uncoordinated pattern among the uterine segments was observed.

CONCLUSION

A well-coordinated activity between the upper and lower uterine segments is demonstrated in normal placental delivery. In some clinical conditions this pattern is not observed, increasing the time for placental delivery and the risk of postpartum hemorrhage.

Sonographic examination of uteroplacental separation during the third stage of labor

OBJECTIVES

To characterize patterns of uteroplacental separation during the third stage of labor, and to investigate their association with previous history of Cesarean section (CS), delays in placental separation and blood loss.

METHODS

In this cohort observational study, continuous ultrasound imaging of uteroplacental separation was performed during the third stage of labor in 78 vaginal deliveries. All women were primiparous and were divided into two groups: those with a previous vaginal delivery (n = 62) and those who had undergone CS (n = 16).

RESULTS

Three patterns of separation were observed: 'down-up' (n = 64), 'up-down' (n = 12) and 'bipolar' (n = 2). Bipolar separation was observed only with fundal placentae. Up-down separation was significantly associated with a history of CS (P < 0.001; odds ratio 14.0; 95% CI, 3.4-57.4) and a longer second stage of labor (P = 0.02).

CONCLUSIONS

In most cases, uteroplacental separation begins at the lower placental pole and proceeds upwards. Women with a history of CS have a higher rate of up-down separation, possibly owing to impaired lower uterine segment contractility.

Intrapartum fetal head position I: comparison between transvaginal digital examination and transabdominal ultrasound assessment during the active stage of labor

OBJECTIVE

To test the null hypothesis that no correlation exists between transvaginal digital and the gold standard technique of transabdominal suprapubic ultrasound assessments of fetal head position during labor. A secondary objective was to compare the performance of attending physicians vs. senior residents in depicting fetal head position by transvaginal digital examination in comparison with ultrasound, respectively.

METHODS

Consecutive patients in active labor at term with normal singleton cephalic-presenting fetuses were included. All participants had ruptured membranes, cervical dilation > or = 4 cm and fetal head at ischial spine station -2 or lower. Transvaginal sterile digital examinations were performed by either senior residents or attending physicians and followed immediately by transverse suprapubic transabdominal ultrasound assessments. Examiners were blinded to each other's findings. Power-analyses dictated number of subjects required. Statistical analyses included Chi-square, Cohen's Kappa test and logistic regression analysis. P < 0.05 was considered statistically significant.

RESULTS

One hundred and two patients were studied (n = 102). In only 24% of patients (n = 24), transvaginal digital examinations were consistent with ultrasound assessments (P = 0.002, 95% confidence interval, 16-33). Logistic regression revealed that cervical effacement (P = 0.03) and ischial spine station (P = 0.01) significantly affected the accuracy of transvaginal digital examination. Parity, gestational age, combined spinal epidural anesthesia, cervical dilation, birth weight and examiner experience did not significantly affect accuracy of the examination. The accuracy of the transvaginal digital exams was increased to 47% (n = 48) (95% confidence interval, 37-57) when fetal head position at transvaginal digital examination was recorded as correct if reported within +/- 45 degrees of the ultrasound assessment. The rate of agreement between the two assessment methods for attending physicians vs. residents was 58% vs. 33%, respectively (P = 0.02) with the +/- 45 degrees analysis.

CONCLUSIONS

Using ultrasound assessment as the gold standard, our data demonstrate an overall high rate of error (76%) in transvaginal digital determination of fetal head position during active labor, consistent with the null hypothesis. Attending physicians exhibited an almost two-fold higher success rate in depicting correct fetal head position by physical examination vs. residents in the +/- 45 degrees analysis. Intrapartum ultrasound increases the accuracy of fetal head position assessment during active labor and may serve as an educational tool for physicians in training.

Down-up sequential separation of the placenta

OBJECTIVE

To characterize the patterns of placental separation during the third stage of labor.

METHODS

Continuous real-time ultrasound was performed during the third stage of labor in 101 normal deliveries. The sequence of placental separation was recorded for determining whether the process was multiphasic, the site from which separation commenced and the mode of its progression.

RESULTS

Separation in 97 cases was multiphasic. Monophasic separation in which all parts of the placenta appeared to separate simultaneously occurred in two cases only. Pathological prolongation of the third stage precluded determination of separation in two cases. Ninety-two cases had a uterine wall placenta (anterior or posterior); the separation commenced at one pole and progressed sequentially towards the opposite side in 89 of them. The process started at the lower pole (down-up separation) in 83/92 cases (90.2%) and began from the upper pole (up-down separation) in only 6/92 cases (6.5%). Nine cases had a fundal placenta; of these the separation was also multiphasic but began sequentially from either the anterior or posterior pole, or simultaneously from both, in 8 (88.9%) cases so that the fundal part was separated last (bipolar separation).

CONCLUSIONS

Placental separation is usually an orderly multiphasic phenomenon that begins mostly from the lower pole of the placenta and propagates sequentially upwards. Fundal placentae, however, separate first at their poles with the fundal part being separated last. Recognition of the sequence of events and understanding of the mechanism of placental separation may aid in detecting cases prone to third-stage complications and in managing pathological ones.

Management of the third stage of labor: an evidence-based approach

The third stage of labor usually is eclipsed by the excitement of the birth of a baby. Evidence shows that management of this stage can directly influence important maternal outcomes such as blood loss, need for manual removal of the placenta, and postpartum hemorrhage. Most of the large trials have compared active management of the third stage to expectant management. Active management includes routine use of cord traction and uterotonins, whereas expectant management can be characterized as one of watchful waiting. The use of herbal therapies and homeopathic remedies lack study; additional factors such as site of birth and hydrotherapy also remain to be explored. However, on the basis of current evidence, if a decrease in postpartum bleeding or avoidance of manual removal is desired, an active approach to third stage is the one that should be adopted until and unless contradictory findings are published.

Use of ultrasound to improve the safety of postgraduate training in obstetrics and gynaecology

Supervised clinical work is perhaps the most valuable component of postgraduate training and has a long-term impact. Senior clinicians not only take the responsibility of teaching and supervising junior doctors but also most of them take the consequences of any clinical failures or mistakes associated with the training. Despite the introduction of simulators and computer-assisted learning, practice on real patients is still required to learn many skills in obstetrics and gynaecology. Training must be safe, because trainees or trainers must not put our patients at risk as part of the process of learning to heal others. Ultrasound can be used to demonstrate and guide several procedures that have been performed 'blindly' in the past. This technology can reduce the risks associated with training and supervision of junior doctors.