COMPLICATIONS OF LABOR
Category: Special Populations
Next Unit: Postpartum Complications
25 minute read
Complications of Labor
Labor is a complex but mostly automatic physiologic process. Many changes occur in the body to allow for the safe passage of the fetus out of the cervix and vaginal canal. There are many ways that this process can go wrong and these complications can easily result in death or disability of the mother and fetus unless properly managed. This section will review some of the most common complications of labor and their EMS management.
PREMATURE RUPTURE OF MEMBRANES (PROM)
Rupture of membranes (ROM) is sometimes referred to, in laymen's terms, as rupture of "the bag of water." Premature rupture of membranes (PROM) is a term used when rupture occurs before labor begins.
The tensile strength of the amniotic membranes (membranes from the placenta which make up the "bag of water," or, amniotic sac) is variable from pregnancy to pregnancy. Some labors put enough stress on this sac to rupture it, some don't. It is commonly seen before and during labor, but it should not occur before 37 weeks gestation.
When it occurs before labor begins, there is a suspicion that an infection has weakened the membranes enough to rupture spontaneously before the stresses of labor can affect them. Once these membranes rupture, they will not re-seal (except rarely when it happens in the 2nd Trimester). Therefore, if fluid can leak out, bacteria can get in, and there is a high risk for infection of the undelivered fetus and placenta ("amnionitis") if there isn't an infection already. Amnionitis is a serious infection that jeopardizes the life of the unborn baby and the health and reproductive organs of the mother.
The earlier that PROM happens before 37 weeks (term is considered 37-41 weeks), the more likely spontaneous preterm labor will occur (or the need to induce preterm labor if infection is suspected).
Management of PROM is all according to obstetrical management flowsheets, so transport is always necessary for any rupture of membranes.
In fact, because ROM typically occurs at or near term, transport is also indicated due to impending labor and/or risk of infection; even if it occurs during labor, which is quite normal, transport is necessary because this is a process that will only end with a delivery.
ROM during labor is quite normal. There should be a clear, flaky fluid that has an unmistakable sweet smell (once you have smelled it, it is forever recognizable). However, rupture of membranes that reveals blood or pus is indicative of placental separation (placental abruption) or serious infection (amnionitis), respectively. The smell should never be foul-smelling (indicative of infection).
Preterm labor, with or without PROM, risks all of the complications that can occur to a preterm infant after delivery:
- hypoxia from undeveloped lungs or persistent fetal circulation,
- developmental and mental delays in childhood due to intracranial hemorrhage,
- jaundice from immature liver, and
- blindness from oxygen toxicity from the use of artificial ventilators.
Therefore, any contractions or pain before 37 weeks should not be treated as any normal labor and represents an obstetrical emergency, requiring transport. This again underscores the need to ask the patient what her due date is.
FALSE LABOR: "Braxton-Hicks" contractions--disorganized tightening of uterine muscle which does not dilate the cervix--can occur any time after 20 weeks gestation and can be quite normal. They are usually no more than just a few an hour--nothing like the every-2-4 minutes seen in active labor. If there is any uncertainty--because active labor is defined as active dilation of the cervix and not a contraction pattern, certainty of labor can only be ascertained with an internal exam: transport is always the safest option.
The journey for the fetal head through the maternal birth canal is one of compression and decompression of the fetal skull. Because the skull bones are not yet fused, as in adults, the openings between them (called the "sutures") allow them to give and adjust during this process.
Labor is safest for the fetal skull (and brain) when the labor pushes the baby toward delivery in a controlled, gradual manner. A precipitous delivery is one in which the descent of the fetus is rushed. How fast is too fast? There is no single answer, as the fetal skull is very flexible (as described above).
However, any precipitous delivery that is so fast that it exceeds the elasticity of the vaginal tissues and tears them is "precipitous." This is an important detail to document so that neurological assessment can be emphasized in the newborn's pediatric evaluation.
The tell-tale signs of vaginal tears are visible with a non-invasive (external) examination of the vagina where bleeding can be seen that is different from the blood of Stage III coming from higher up in the uterus.
(Stage I of labor is up to the time of complete cervical dilation; Stage II is from complete dilation to delivery of the infant; Stage III is from delivery of the infant to delivery of the placenta.)
SECONDARY ARREST OF LABOR
Secondary arrest of labor is a labor that has begun and then has stalled out.
It is usually encountered in-home deliveries where labor has been going on for days. Some home-birth enthusiasts stubbornly follow an agenda of natural processes, even to the point of refusing medical intervention when abnormalities of labor are evident, such as secondary arrest of labor.
In this situation, the woman's uterus has exhausted its ability to contract.
Even in a woman who has had several babies (in whom labor is typically quick), the cervix usually dilates about a cm/hour, making delivery expected within 12-15 hours. Any longer than this may represent secondary arrest and warrants transport. Babies are tough, but they, too, can exhaust their energy reserves, creating fetal distress.
MECONIUM is a green/black tarry stool made up of vernix (oily skin), lanugo (fine fetal hair), and other fetal waste structures ingested by the fetus normally during gestation.
If a fetus experiences hypoxia, this distress may provoke an attempt to take a breath while inside the uterus, depressing its diaphragm, and pressing stool along its colon out through the rectum.
This meconium is very irritating to a baby's lungs, and if the baby "inhales" it while in the womb, it may be a setup for a serious lung inflammation (called "pneumonitis") upon delivery.
Because it implies fetal distress, the rupture of membranes that reveals meconium is also an obstetrical emergency. Of course, ROM warrants transport itself, but meconium is crucial to document so that the baby's airways can be scrupulously examined after birth to make sure the meconium wasn't taken into the lungs, which can cause pneumonitis. Also, such documentation will prepare the attendant at delivery to suction the nasopharynx aggressively of any residual meconium before the baby takes in his or her first breath, which would deliver the meconium deep into the lungs. Forewarned is forearmed!
Closely associated with the subject of meconium is "fetal distress," a term that been replaced by more specific terms such as "fetal bradycardia," "fetal acidosis," etc. (Fetal bradycardia results in acidosis if not corrected.) Fetal bradycardia is a baseline rate of < 110 bpm, although normal variation can sometimes see a dip below 110 temporarily (not baseline).
There are two ways fetal bradycardia can occur:
- The unborn baby does not have the resilience (reserve) to tolerate the stress of labor (e.g., small for gestational age infants, placental abnormalities interfering with nutrition and oxygenation, placental calcifications--aging of the placenta post-term, and other reasons. As such, meconium is a frequent co-finding with fetal bradycardia. The bradycardia due to a baby's inability to tolerate labor will be most pronounced after the contraction begins when the blood supply is reduced.
- Maternal hypoxia. The mother is the incubator, and when the incubator is hypoxic, so is her baby.
Any evaluation of labor should include a cursory look to make sure crowning isn't occurring (the baby's head pushing through the vagina). However, instead of the fetal head, sometimes a foot or hand will be seen extruding from the vagina. This is called an abnormal "lie," and can present in all of the variations of breech presentation. Many if not most cases of an abnormal lie are incompatible with vaginal delivery and can result in a baby stuck in the birth canal, leading to injury and death; therefore, the sooner the patient is transported, the better.
RUPTURE OF THE UTERUS
Rupture of the uterus is the most life-threatening labor-related event that can occur. If contractions are too strong and fast, the thin lower uterine segment, also being distorted by the fetus, can tear.
Tissue which has been scarred from a previous C-section is particularly at risk. Ask about any history of a previous C-section.
The uterus is a very vascular organ and a rupture constitutes a hemorrhagic crisis that typically has a high mortality rate for both mother and child. Pain between contractions can occur with it (as it also can with placental abruption), so any constant pain requires expedient transport and large-bore IVs, preferably two, to anticipate possible massive bleeding. Alternatively, sometimes with rupture the whole uterus becomes flaccid, and visible fetal movement under the mother's skin becomes obvious (fetus is outside of the womb).
►Call to Action: TRANSPORT
Any contractions in a woman with a previous C-section warrants immediate transport.