The placenta should be completely expulsed within 30 to 60 minutes after vaginal delivery, depending on labor management. Premature births may be associated with longer times until placenta expulsion and higher risks of RP. Women with uterine pathologies, e.g., intra-uterine adhesions or neoplasms, as well as those patients who previously underwent surgery have a higher risk of RP as well.

Upon placenta detachment, a considerable amount of blood may be discharged from the vagina. At the same time, the uterine fundus contracts, changes its shape from discoid to globular and fundal height increases. The umibilical cord should elongate. If these observations are made, the placenta is expulsed and subsequent examination of this tissue does not reveal any anomalies, the likelihood for RP decreases significantly.

However, small parts of the placenta may still remain in the uterus, e.g., in case of placenta accreta. Women who don't undergo sonography or other diagnostic measures to assure complete detachment and expulsion of the placenta may experience hemorrhages and abdominal cramps. If the condition prolongs, ill-smelling vaginal discharge and fever may be observed. In some cases, breast milk release is inhibited.

• Intravenous Administration

  administration of oxytocin increases effectiveness. [emedicine.medscape.com]

• Aspiration

  Benefits: Avoids possible difficult intubation and pulmonary aspiration. Drawbacks: Patient may become over-sedated with a loss of airway reflexes and potential for pulmonary aspiration, remembering that she should be considered a full stomach. [clinicalpainadvisor.com]

  Surgical Management of Miscarriage and Removal of Persistent Placental or Fetal Remains (Consent Advice No. 10 – Joint with AEPU) professionals obtaining consent from women undergoing surgical management of miscarriage with electric or manual vacuum aspiration [rcog.org.uk]

  […] coagulation defects O73 Retained placenta and membranes, without hemorrhage O73.0 Retained placenta without hemorrhage O73.1 Retained portions of placenta and membranes, without hemorrhage O74 Complications of anesthesia during labor and delivery O74.0 Aspiration [icd10data.com]

• Cough

  […] the woman sits on the toilet and coughs/sneezes to get the placenta out. Good luck! [mothering.com]

• Placental Disorder

  A need for intervention due to placental disorder during the third stage of labor was noted in 4.2% of all deliveries. [ncbi.nlm.nih.gov]

  Placental transport Placental types and pathology of the placenta: Circumvallate (circummarginate) placenta, succenturiate lobe, bipartite placenta, marginal insertion of the cord, placenta membranacea, placenta accreta, placenta previa Placental disorders [umfcv.ro]

• Cesarean Section

  Placenta previa in women with previous cesarean section is associated with a high risk for PPH and retained placenta. [ncbi.nlm.nih.gov]

• Vaginal Bleeding

  Call your doctor or nurse call line now or seek immediate medical care if: You have severe vaginal bleeding. This means you are soaking through a pad each hour for 2 or more hours or passing blood clots. [myhealth.alberta.ca]

  […] or plastic bag.  If reusing surgical gloves, submerge them in 0.5% chlorine solution for 10 minutes for decontamination 20.  Use antiseptic hand rub or wash hands thoroughly with soap and water and dry with a clean, dry cloth or air dry.  Monitor vaginal [slideshare.net]

  I had vaginal bleeding 2 1/2 weeks ago & went to the e.r. I was told I have placenta previa. I hope it moves up! I don’t want a c-section. This is my 3rd pregnancy and I can’t believe I have this condition. [i-am-pregnant.com]

Suspicion for RP may arise if the above mentioned signs of placenta detachment are not observed or if they are not followed by placenta expulsion. The former scenario may indicate uterine atony that leads to placenta adherens.

In contrast, a woman suffering from incarcerated placenta will present uterine contractions and blood loss, but placenta expulsion is delayed or does not occur at all. Here, vaginal examination may reveal partial closure of the cervix. In most cases, the placenta can be palpated through the narrow opening still present in this organ.

Extent and severity of placenta accreta give rise to a wide range of symptoms. Penetration of the uterine wall by chorionic villi may have been diagnosed during pre-partal sonographic examinations. More superficial forms of placenta accreta may not have been visible. The abnormal attachment of the placenta to the uterus may provoke symptoms similar to those of placenta adherens, but uterine contractions are often present. Often, placenta adherens and placenta accreta are distinguished when trying to manually remove the placenta.

If anomalies are suspected, sonographic exams should be carried out to assess the condition of uterus and placenta [4]. A thickened uterine wall and possibly even a clear demarcation of the placenta indicates that placenta detachment took place while at sites of persistent adhesion the uterine wall will appear thin.

Different forms of RP require distinct therapeutic approaches. Thus, a thorough vaginal and sonographic examination is a prerequisite for choosing an appropriate treatment.

Placenta adherens can most frequently be resolved by manual removal of the tissue. The procedure should take place under aseptic conditions and the patient should either receive sedatives or anesthetics in order to prevent pain. Also, prophylactic administration of broad-spectrum antibiotics is often recommended because manual extraction of the placenta is associated with an increased risk of infection [5] [6]. In some cases it might be necessary to apply uterine relaxants in order to widen the birth canal and to allow passage of a hand (e.g., glyceryl trinitrate, 50 to 200 µg i.v.).

An alternative approach to placenta adherens treatment is the use of uterotonic drugs. Intraumbilical vein injections of PGF2α, PGE or oxytocin have been realized to this end and usually induce placenta expulsion within approximately ten minutes [7] [8]. Prostaglandins seem to be most effective and mediate fast effects. Lack of effect of oxytocin has been suggested to be due to inactivation by placental enzymes [9]. Of note, umbilical vein catheterization may also be applied to administer these compounds [10]. Both methods require the drugs to be diluted in sufficiently large volumes of saline solution [11].

Uterotonic drugs, particularly prostaglandin analogues, may also be applied systemically to resolve placenta adherens and avoid the necessity for manual extraction [12] [13].

Uterotonic drugs are contraindicated in cases of incarcerated placenta due to cervical closure. Here, uterorelaxants such as glyceryl trinitrate need to be administered if cord traction alone is insufficient to extract the placenta [7] [14] [15] [16] [17]. General anesthesia may further relax the uterus and facilitate removal of the trapped placenta.

If manual extraction of the placenta cannot be realized because of abnormal attachment of the latter to the uterus, extent and severity of placenta accreta will determine subsequent measures. Mild cases may be resolved by gentle manual dissection of placenta and uterus and subsequent extraction. Curettage is associated with increased risks of perforation, hemorrhage and post-partal formation of intra-uterine adhesions. In more severe cases that prove resistant to application of uterotonic drugs, hysterectomy may be the safest treatment to avoid life-threatening hemorrhages. If this is not an option, balloon tamponade or uterine artery embolization may be attempted. Conservative treatment of placenta accreta is not recommended.

Failure of placenta detachment and expulsion may lead to severe, potentially life-threatening obstetric hemorrhages. This condition requires immediate action in order to prevent mortality rates as typically seen in developing countries. Furthermore, intra-uterine adhesions may develop and affect fertility. Material retained inside the uterus also increases the risk for infection, endometritis and puerpural sepsis.

During pregnancy and delivery, the placenta remains attached to the uterus and guarantees supply of oxygen and nutrients as well as removal of metabolic products to and from the unborn child. After delivery, endocrinological changes should induce uterine contractions in order to accelerate separation of the placenta from the uterus. This process may be disturbed at distinct levels [2].

If the myometrial tone cannot be increased accordingly, this uterine inertia interferes with placental detachment and expulsion. This condition is termed placenta adherens.

In rare cases, the placenta cannot be expulsed although uterine contractions occur. This may be caused by an abnormally strong attachment of the placenta to the uterine wall, a condition designated placenta accreta.

If the cervix has closed, even a properly detached placenta cannot be expulsed. These patients suffer from incarcerated placenta.

Under an epidemiologic point of view, there are major differences between RP in developed and under-developed countries. There is a high incidence of RP in the Western World and it has been estimated that up to 3% of vaginal deliveries are complicated by this condition. This rate is significantly higher than in developing countries. However, due to limited possibilities of treatment, the lower incidence is associated with mortality rates of up to 10% [2]. RP accounts for approximately one out of five severe obstetric hemorrhages [3].

A complex network of endocrinological changes comprising fetal, placental and extra-placental hormone release accounts for the fact that levels of uterotonic hormones rise at the precise points in time to promote delivery and subsequent expulsion of the placenta. In this context, prostaglandins F2α (PGF2α) and E (PGE) are the main mediators of post-partal uterine contractions. They increase the oxytocin receptor density of the uterus, render it more sensitive to this hormone and thus promote contractions. The enzyme cyclooxygenase-2 accounts for the synthesis of these tissue hormones and its expression levels rise during delivery.

Tight vascular connections and a considerable blood flow are necessary to meet the increasing demands of the unborn child for oxygen and nutrients. This connection is broken during delivery and prompt uterine contractions are necessary to complete placenta detachment and to reduce bleeding through these vessels.

In most cases of RP, the above described cascade leading to uterine contractions is disturbed at some level and the placenta cannot be separated from an atonic uterus. Possibly, enhanced levels of inhibitors of myometric activity play an important role. RP results in an immediate risk for severe hemorrhages. But tissue debris remaining inside the uterus also poses a high risk of infection, puerpural sepsis and long-term fertility issues.

Active management of the third stage of labor accelerates placenta expulsion and decreases the risk for RP. To date, prophylactic administration of uterotonic drugs cannot be recommended to avoid placenta adherens and possibly incarcerated placenta. Severe forms of placenta accreta may be recognized in pre-partal sonographic examinations.

As per definition, retained placenta (RP) is the failure of expulsion of the afterbirth within 30 minutes of delivery [1]. This third and last stage of labor is completed within the aforementioned time frame by 98% of all patients, provided that labor is managed actively and that the pregnancy had advanced to the third trimester [2]. If expulsion of the placenta is not accelerated by cord traction or administration of uterotonic agents, this time frame augments to 60 minutes. Also, premature birth is associated with longer times until placenta expulsion and a higher risk of RP. Thus, the precise conditions of the mother, management of labor and delivery have to be taken into account before diagnosing RP. On the other hand, diagnosis and initiation of treatment should not be excessively delayed since RP is a potentially life-threatening condition. There is a high risk for hemorrhages in women with RP. Furthermore, this tissue may become infected, provoke endometritis and septicemia and cause long-term fertility issues.

During pregnancy, the placenta serves as an important connection between the unborn child and their mother. It guarantees supply of oxygen and nutrients and removal of metabolic products. In order to fulfill this function, it is very well perfused. After delivery, the uterus should contract, thus induce placenta detachment and reduce residual bleeding. Then, the placenta should be expulsed. This should happen within 30 minutes after delivery. Otherwise, the woman is diagnosed with retained placenta (RP).

Causes

Women giving premature birth or suffering from pre-existing uterine lesions, e.g., intra-uterine adhesions or tumors, have a greater risk of RP.

This condition may result from insufficient uterine contractions to induce placenta detachment, from an abnormally tight connection between placenta and uterus that cannot be resolved even if the uterus contracts normally, or from the impossibility to expulse a detached placenta through already narrowed birth ways.

Symptoms

Complete failure to expulse the placenta is detected shortly after birth. However, some women retain only parts of the placenta in their uterus and experience symptoms of malaise, fever and abdominal cramps days after being sent home. Considerable bleedings or an ill-smelling vaginal discharge are also signs of an intrauterine pathology and should be revised as soon as possible.

Diagnosis

The condition of placenta and uterus may be revealed through vaginal examinations and palpation of the corresponding organs or by applying sonography. Indeed, certain forms of RP may be detected during pre-partal sonographic examinations.

Treatment

Treatment depends on the precise type of RP.

In case of placenta adherens, i.e., an insufficient detachment of the placenta from the uterus due to diminished uterine contractions, drugs that provoke contractions may be administered. This therapeutic approach is often sufficient to induce natural expulsion of the placenta. Manual extraction is also performed frequently, but is associated with higher risks of infection.

If the placenta cannot be expulsed because it is abnormally tightly connected to the uterus, manual extraction may still be possible. In more severe cases it bears a high risk for hemorrhages. If therapeutic measures to arrest such bleedings do not yield the desired response, removal of the uterus may be the treatment of choice to save the life of the mother.

In case of RP due to narrowed birthways, drugs that mediate relaxation of the uterus may be applied. Then, the placenta may be spontaneously expulsed or can be removed by manual extraction.

1. Deneux-Tharaux C, Macfarlane A, Winter C, Zhang WH, Alexander S, Bouvier-Colle MH. Policies for manual removal of placenta at vaginal delivery: variations in timing within Europe. Bjog. 2009; 116(1):119-124.
2. Weeks AD. The retained placenta. Best Pract Res Clin Obstet Gynaecol. 2008; 22(6):1103-1117.
3. Al-Zirqi I, Vangen S, Forsen L, Stray-Pedersen B. Prevalence and risk factors of severe obstetric haemorrhage. Bjog. 2008; 115(10):1265-1272.
4. Herman A, Weinraub Z, Bukovsky I, et al. Dynamic ultrasonographic imaging of the third stage of labor: new perspectives into third-stage mechanisms. Am J Obstet Gynecol. 1993; 168(5):1496-1499.
5. Ely JW, Rijhsinghani A, Bowdler NC, Dawson JD. The association between manual removal of the placenta and postpartum endometritis following vaginal delivery. Obstet Gynecol. 1995; 86(6):1002-1006.
6. Atkinson MW, Owen J, Wren A, Hauth JC. The effect of manual removal of the placenta on post-cesarean endometritis. Obstet Gynecol. 1996; 87(1):99-102.
7. Chedraui PA, Insuasti DF. Intravenous nitroglycerin in the management of retained placenta. Gynecol Obstet Invest. 2003; 56(2):61-64.
8. Rogers MS, Yuen PM, Wong S. Avoiding manual removal of placenta: evaluation of intra-umbilical injection of uterotonics using the Pipingas technique for management of adherent placenta. Acta Obstet Gynecol Scand. 2007; 86(1):48-54.
9. Yamahara N, Nomura S, Suzuki T, et al. Placental leucine aminopeptidase/oxytocinase in maternal serum and placenta during normal pregnancy. Life Sci. 2000; 66(15):1401-1410.
10. Pipingas A, Gulmezoglu AM, Mitri FF, Hofmeyr GJ. Umbilical vein injection for retained placenta: clinical feasibility study of a new technique. East Afr Med J. 1994; 71(6):396-397.
11. Pipingas A, Hofmeyr GJ, Sesel KR. Umbilical vessel oxytocin administration for retained placenta: in vitro study of various infusion techniques. Am J Obstet Gynecol. 1993; 168(3 Pt 1):793-795.
12. van Beekhuizen HJ, de Groot AN, De Boo T, Burger D, Jansen N, Lotgering FK. Sulprostone reduces the need for the manual removal of the placenta in patients with retained placenta: a randomized controlled trial. Am J Obstet Gynecol. 2006; 194(2):446-450.
13. van Beekhuizen HJ, Pembe AB, Fauteck H, Lotgering FK. Treatment of retained placenta with misoprostol: a randomised controlled trial in a low-resource setting (Tanzania). BMC Pregnancy Childbirth. 2009; 9:48.
14. Dufour P, Vinatier D, Puech F. The use of intravenous nitroglycerin for cervico-uterine relaxation: a review of the literature. Arch Gynecol Obstet. 1997; 261(1):1-7.
15. Jha S, Chiu JW, Yeo IS. Intravenous nitro-glycerine versus general anaesthesia for placental extraction--a sequential comparison. Med Sci Monit. 2003; 9(7):CS63-66.
16. Lowenwirt IP, Zauk RM, Handwerker SM. Safety of intravenous glyceryl trinitrate in management of retained placenta. Aust N Z J Obstet Gynaecol. 1997; 37(1):20-24.
17. Bullarbo M, Tjugum J, Ekerhovd E. Sublingual nitroglycerin for management of retained placenta. Int J Gynaecol Obstet. 2005; 91(3):228-232.