Why is oxytocin administered after birth

This idea caught on, especially in the s, after studies found a reduction in PPH with the routine use of ergot injections in the third stage of labor. However, ergot was also linked to side effects in some people, including high blood pressure, nausea, vomiting, headache, and abdominal pain. Today, the World Health Organization still recommends ergot preparations as an effective uterotonic drug for birthing people without high blood pressure disorders WHO, But in settings where multiple uterotonic options are available for active management of the third stage of labor, the WHO recommends synthetic oxytocin over the other options.

Synthetic oxytocin first came into use in the s, much later than ergot. Soon after, in the s, active management uterotonic drug plus immediate cord clamping and controlled cord traction became popular in many hospital settings to try and prevent postpartum hemorrhage Aflaifel and Weeks, The hormone oxytocin was discovered in when Sir Henry Dale of London found that an extract from the human pituitary gland, a pea-sized structure at the base of the brain, caused uterine contractions in a pregnant cat Magon and Kalra, Research on oxytocin in the early s used extracts from cow and pig pituitary glands.

Today, commercially sold oxytocin is prepared synthetically in laboratories. Other uterotonics are also used for PPH prevention, including carbetocin, prostaglandin analogues such as misoprostol, ergot alkaloids, or combinations of these oxytocin plus ergometrine, or oxytocin plus misoprostol Vogel et al.

During pregnancy, they found that blood levels of oxytocin gradually rise, increasing by 3 to 4 times. Levels of oxytocin rise even more in labor, when pulses of the hormone become larger and more frequent to contract the uterus and help the progress of labor. The maximal frequency of pulses was found to be 3 pulses per 10 minutes not tied to the frequency of contractions just before the birth. There is a large pulse of oxytocin during the actual birth when the fetal head emerges, and pulses continue during the third stage of labor with the birth of the placenta.

When it detaches, this leaves a placenta-sized wound on the inside of the uterus. Without effective contractions, the uterine blood vessels are left wide open and enormous amounts of blood can be lost very quickly.

Interestingly, researchers are now studying intranasal nose-to-brain delivery of synthetic oxytocin as a way of crossing the blood brain barrier and treating different brain diseases Quintana et al.

Oxytocin in the body both natural and synthetic causes the uterus to contract by binding with oxytocin receptors on the cell surface. When there is a lot of oxytocin, the body compensates by decreasing the number of oxytocin receptors to maintain body equilibrium balance.

Getting that break from oxytocin exposure protects against receptor desensitization, helping to keep contractions effective. Postpartum hemorrhage PPH is bleeding too much after birth. When hemorrhage occurs from day two up until 12 weeks after birth, it is called secondary, late, or delayed PPH.

Loss of muscle tone in the uterine muscle is also called uterine atony. Since it is the most common cause of PPH, care providers should suspect it first, before the other possible causes. Labors that are prolonged or rapid with very strong contractions can also lead to uterine atony and increase the risk of PPH.

Other factors that can decrease tone in the uterus besides exhaustion of the uterine muscles include infection, having a large uterus e. Trauma in birth can be physical or psychological.

In this context, trauma refers to physical injury—such as uterine rupture; tears to the cervix, vagina, or perineum; and episiotomy—that can cause PPH. Tears must be repaired in order to stop the bleeding. When portions of the placenta or membranes are left behind in the uterus they can prevent adequate contractions and contribute to PPH.

The tissue must be removed to stop the bleeding. Having disorders of the placenta can put the birthing person at increased risk for leaving tissue behind Association of Ontario Midwives, For example, placenta accreta is a serious condition where the placenta grows too deeply into the uterine wall, most often due to scarring from a prior Cesarean or other uterine surgery. If not, she may require treatment to help with blood clotting.

They can be pre-existing e. There is no standard definition of PPH that is used in the research and in professional guidelines around the world. Some amount of blood loss is normal and expected after childbirth. However, too much blood loss is a childbirth emergency that can be life threatening. The answer to the question of where to draw the line between normal, physiologic blood loss and excessive blood loss i. Until recently, this definition for PPH was applied to all birthing people regardless of their health status and whether or not they suffered any harmful effects from their blood loss after birth.

Postpartum hemorrhage is now being redefined based on research showing that healthy birthing people are usually unharmed by blood loss up to mLs Anger et al. For perspective, blood loss around mL is similar to a routine blood donation, a loss of about 2 cups of whole blood, which is usually well tolerated by healthy people. The blood that is lost after birth is sometimes also diluted with urine and amniotic fluid. In addition, there is an expansion of blood volume that occurs during pregnancy by about mL that helps to protect mothers against harmful effects of blood loss after birth Erickson et al.

A review by Erickson et al. Some people experience signs and symptoms before losing mL of blood and others can lose mL or more of blood after birth without clinical effects. Birthing people with anemia, low body mass, and those who have decreased blood volume from dehydration or preeclampsia, for example are more likely to feel the effects of losing even a few hundred mL of blood Association of Ontario Midwives, The U.

Visually estimating how much blood has been lost is the most common method of determining blood loss volume after birth, where the care provider looks at the amount of blood lost and tries to estimate its volume Diaz et al. Research has consistently shown that care providers tend to over- or under-estimate blood loss volume with their visual estimates. The same holds true across provider types and birth settings.

Smaller volumes of blood loss tend to be overestimated and larger volumes of blood loss tend to be underestimated Hancock et al. So, providers might see what they expect to see based on their training about typical blood loss after birth.

There are conflicting findings on whether years of experience and additional training can improve visual estimation skills. When blood loss is actually measured rather than visually estimated, there is less potential for introducing bias from the diagnosing clinician. Racial bias i. A large study with over , participants with PPH in U.

Quality improvement projects to reduce PPH usually include quantified blood loss as part of a larger safety bundle to improve readiness, recognition and response to PPH. In this way, using quantified blood loss helps improve communication between providers.

A recent study on a large quality collaborative in California found that hospitals using the PPH safety bundle with support from outside mentors were able to reduce severe maternal complications from PPH Main et al. Although quantified blood loss is a more accurate and objective way to assess blood loss volume, it may not be practical in all birth settings.

And currently, there is no evidence from randomized trials that measuring blood loss results in better clinical outcomes compared to visually estimating blood loss. A Cochrane review found only two trials evaluating methods for estimating blood loss after vaginal birth Diaz et al.

However, the promising findings from the large quality improvement collaborative in California suggest quantified blood loss may offer benefits over visual estimation. A review of the research concluded that these are also important factors in early diagnosis and treatment of PPH. Estimates vary widely, depending on which definition of PPH is used.

In the United States U. However, the rate of severe PPH that led to blood transfusion, surgical removal of the uterus, or surgical repair of the uterus rose from 1. They found that PPH rose significantly from 4. Australia, Canada, the U.

They speculate that it may relate to an increase in mothers with risk factors for PPH: more people giving birth after Cesarean, more multiple pregnancies, and an increase in induction, augmentation, and epidural use.

However, there is very limited evidence to support these possible explanations. Researchers in Canada looked back at over , births to single babies between and to try and explain their recent rise in PPH Kramer et al. All of the births took place at a single hospital in Montreal.

Overall, 2. In addition to the increase in PPH, there was also an increase in labor induction, labor augmentation, and prior Cesarean section over the study period.

The researchers concluded that these three risk factors induction, augmentation, and prior Cesarean appeared to largely explain the increase in PPH. However, another study from Australia was not able to explain their rise in PPH by taking risk factors into account. Again, blood loss was based on visual estimates, and provider management approaches varied. More research is needed, using a standardized definition for early PPH, because we do not yet have solid evidence on why the rate of PPH is increasing.

It may be useful to discuss these risk factors with your care provider and consider how they apply to your unique situation when deciding between active and expectant management for the third stage of labor.

Some of these risk factors can be known before the birth, and some can only be known after the birth. The data come from population studies in the U. Providers are careful to monitor the time that passes after the birth and before the placenta is expelled because a longer third stage of labor is linked to increased risk of PPH. When the placenta is not expelled after birth and remains in the uterus, it is diagnosed as a retained placenta and is often manually removed. Manual removal of the placenta is an invasive procedure that can be painful.

The care provider puts on a sterile glove and inserts a hand through the cervix and into the uterus. In this study, most of the birthing people received active management of the third stage of labor. Factors linked to a longer third stage of labor in this study included preterm birth a major risk factor , giving birth lying in bed as opposed to upright , preeclampsia, augmented labor, and being a first-time mother.

Recent meta-analyses of randomized trials multiple trials combined into one large study have not found a significant difference in the length of the third stage of labor with active versus expectant management Begley et al.

However, earlier data mentioned above suggest that the third stage of labor may be longer with expectant management. In the U. They recommend a change from expectant to active management if the birthing person has PPH or the placenta is not expelled within one hour of the birth of the baby. A recent Cochrane review examined four randomized trials with nearly 5, participants who were assigned to active versus expectant management in hospital settings Begley et al.

Three of the studies were from the United Kingdom and one was from Ireland. It is worth noting that the care providers who attended the births in these studies were more familiar with active management than expectant management.

Some of the participants were considered at low risk for excessive bleeding after birth and some were at higher risk i. Many of the participants in these studies had their labors induced or augmented. However, they point out that the average difference between groups may not be clinically important, as routine blood donation reduces Hb levels by a similar amount without ill effects in healthy women, and levels may rise within a few days after birth.

On a side note, research on planned home birth in the U. They found no difference in the number of babies admitted to newborn care units or the number of babies with jaundice requiring treatment between the participants who received active versus expectant management. There was also no evidence that active management makes a difference in the need to remove the placenta manually or the average length of the third stage of labor. In addition to the benefits for blood loss prevention, there were also some downsides to active management for mothers and babies low-quality evidence.

The increase in the number of people returning to the hospital with bleeding is concerning—for every 65 people who had active management, one returned to the hospital because of bleeding.

The authors think that the increased risk of late bleeding might have been due to shreds of tissue left behind after cord traction. Not surprisingly, active management reduced the average birth weight of the baby by about 80 grams; moderate-quality evidence due to lower blood volume from early cord clamping.

This effect could probably be avoided by changing the active management approach to include delayed cord clamping waiting until the cord stops pulsating. All of the participants in the studies were planning to give birth vaginally to single, head-down babies.

In conclusion, the Begley et al. Active management reduced the risk of severe blood loss and anemia after birth in a group that included both people at lower risk for bleeding and those at higher risk for bleeding. However, it also increased the need for pain medication for afterpains and increased the risk of excess bleeding following hospital discharge. It is possible that the benefits of reduced blood loss can be achieved with less harm by making changes to the active management approach.

The authors recommend that pregnant people be given information on both the potential benefits and harms of active management to support informed choice. If someone chooses expectant management, it is important that they have a uterotonic drug available if excess bleeding occurs.

The Begley et al. Unfortunately, all of the mixed managements differed, so they were not able to draw firm conclusions on any of the approaches.

Out of the four trials on mixed management, only one was considered to be high quality. This study included healthy pregnant people in Sweden between 34 and 43 weeks with single, head-down babies Jangsten et al.

However, the study did include people with risk factors for PPH. About people were randomly assigned to active management and people were assigned to mixed management. The active management approach consisted of giving synthetic oxytocin within 2 minutes of birth, immediate cord clamping, controlled cord traction while the birthing person pushed, and uterine massage after birthing the placenta. In comparison, the participants assigned to mixed management received a placebo of IV saline solution instead of the synthetic oxytocin.

They had the cord clamped immediately, but did not receive any cord traction during pushing. Again, everyone received uterine massage after the placenta was birthed. All blood loss up to two hours after birth was collected and measured.

This study found that active management was linked to lower pain scores at two hours after birth compared to mixed management without a uterotonic.

Heim completed a family medicine residency at the University of Missouri, Columbia. SIM S. Address correspondence to Karen L. Maughan, M. Reprints are not available from the authors. Labor and delivery. Obstetrics: normal and problem pregnancies. New York: Churchill Livingstone, Abouzaher C.

Antepartum and postpartum haemorrhage. Health dimensions of sex and reproduction: the global burden of sexually transmitted diseases, HIV, maternal conditions, perinatal disorders, and congenital anomalies. Boston: Harvard University Press, —4. Royston E, Armstrong S. Preventing maternal deaths. Geneva: World Health Organization, A comparison between visual estimation and laboratory determination of blood loss during the third stage of labor.

Obstet Gynecol. Active versus expectant management in the third stage of labor. Cochrane Database Syst Rev. International survey on variations in practice of the management of the third stage of labour. Bull World Health Organ. New York: McGraw-Hill, Preventing postpartum hemorrhage in low-resource settings. Int J Gynaecol Obstet.

Prophylactic use of oxytocin in the third stage of labour. Prophylactic ergometrine-oxytocin versus oxytocin for the third stage of labour. Comparison of carbetocin and oxytocin for the prevention of postpartum hemorrhage following vaginal delivery: a double-blind, randomized trial. J Obstet Gynaecol Can. Prostaglandins for prevention of postpartum haemorrhage.

A prospective cohort study of oxytocin plus ergometrine compared with oxytocin alone for prevention of postpartum haemorrhage. Br J Obstet Gynaecol. Controlled cord traction versus minimal intervention techniques in delivery of the placenta: a randomized controlled trial. Am J Obstet Gynecol. A randomized controlled trial comparing oxytocin administration before and after placental delivery in the prevention of postpartum hemorrhage.

Coordinator of the series is David Slawson, M. Once this small study was removed from the meta-analysis, heterogeneity was eliminated and the treatment effect favoured intravenous oxytocin average RR 0. There may be little to no difference between the two routes of oxytocin administration in terms of additional uterotonic use average RR 0. Although intravenous compared with intramuscular administration of oxytocin probably results in a lower risk for serious maternal morbidity e.

Most events occurred in one study from Ireland reporting high dependency unit admissions, whereas in the remaining three studies there was only one case of uvular oedema. There were no maternal deaths reported in any of the included studies very low-certainty evidence.

There is probably little or no difference in the risk of hypotension between intravenous and intramuscular administration of oxytocin RR 1. Subgroup analyses based on the mode of administration of intravenous oxytocin bolus injection or infusion versus intramuscular oxytocin did not show any evidence of substantial differences on the primary outcomes. Similarly, additional subgroup analyses based on whether oxytocin was used alone or as part of active management of the third stage of labour AMTSL did not show any evidence of substantial differences between the two routes of administration.

What is the issue? Why is this important? What evidence did we find? What does this mean? Authors' conclusions:. Search strategy:. Selection criteria:. Data collection and analysis:. The optimal interval for administering the oxytocin IV infusion has not been well studied. I recommend the infusion be continued for at least 4 hours following delivery. My recommendation is based on the observation that when oxytocin is discontinued shortly after birth, the risk of a delayed postpartum hemorrhage increases significantly.

IV boluses of oxytocin, at doses of 5 to 10 units, have been reported to be followed by hypotension, 3 ischemic changes detected by electrocardiogram, 4 , 5 and maternal death.

Bottom line: Avoid IV bolus administration of oxytocin at doses of 5 units or 10 units due to adverse effects. Misoprostol is likely somewhat less effective than oxytocin in reducing the risk of postpartum hemorrhage, 8 but it is more effective than placebo.

Resource-limited settings. IV infusion or IM injection of a uterotonic may be difficult to perform outside of a hospital, in a resource-limited setting.