Preterm Labour

Preterm Labour

Overview of Preterm Labour

  • A typical full-term pregnancy lasts 37 to 42 weeks. The duration is calculated from the first day of the last menstrual period to childbirth.

  • Preterm labor, also known as premature labor, refers to the onset of uterine contractions before 37 weeks but after 20 weeks of pregnancy (gestation).

  • An extremely preterm infant can be born at 26 weeks' gestation.

Risks Associated with Preterm Infants

  • The earlier a premature infant is born, the higher the risk of complications.

  • If delivery occurs after 36 weeks, the infant's risks of encountering problems are very low. Most infants born at 36- and 37-weeks are treated similarly to full-term newborns.

  • Labour and delivery occurring before the 20th completed week of pregnancy is classified as a miscarriage.

  • A preterm infant can be born at 35 weeks' gestation.

Characteristics of Premature Infants

  • Premature infants often exhibit:

    • Thin skin and reddish color.

    • Body covered in long silky hairs and a thick layer of vernix.

    • Stick-like limbs and typically engage in sudden bursts of spontaneous, jerky, angular activity.

    • Largely remain quiet and display minimal responses to environmental changes, seldom waking to feed even after many hours.

    • Poor heat regulation and irregular respiration.

    • They suck weakly and become quickly exhausted.

Conduct of Preterm Labour

  • During the second stage of labor, care should be taken to avoid sudden excessive pressure on the small immature skull.

  • An episiotomy may be performed if there is a risk that an easy delivery will be hindered by a rigid perineum.

  • Upon delivery:

    • Cut the umbilical cord without delay.

    • Clear the airway of the infant immediately.

    • Wrap the infant in a warmed towel and transfer in a head-down position preferably to a prepared incubator.

    • Clear the nasopharynx again using suction and a rubber catheter.

Feeding of Premature Infants

  • Premature infants should be fed at regular intervals by the mother since they are unable to suck efficiently and are at risk of fatigue without crying when hungry.

  • Tube feeding may be necessary for the smallest infants.

  • Full-term babies are expected to cry when hungry and refuse to suck when full, but premature infants require their daily needs to be systematically calculated and administered.

Hazards of Prematurity

  • Premature infants experience significant risks due to underdeveloped major organs, leading to various health problems:

    • Lungs - breathing complications (e.g., Respiratory Distress Syndrome, RDS).

    • Retinopathy - high oxygen concentrations can damage the retina, resulting in vitreous exudate separation of the retina and fibrosis of internal orbital structures.

    • Immune system issues - heightened risk of infections such as group B streptococcal septicemia.

    • Brain issues - increased risk for conditions like mental retardation, bleeding, and cerebral palsy.

    • Risks to organs such as the gut, kidneys, or liver.

    • Anemia - types include hypochromic and isochromic; treated with blood transfusions.

    • Edema - often presents with a shiny, wax-like appearance caused by chilling during or after delivery.

    • Hemorrhages - potential occurrences in the lungs, brain, adrenals, and gastrointestinal tract; caused by factors including hypoprothrombiaemia, capillary fragility, anoxia, and infection. Treatment includes administration of 2.5mg of Vitamin K at birth, with repeats bi-weekly.

Symptoms of Preterm Labour

  • Indications of preterm labor include:

    • 4 or more contractions per hour.

    • Strong contractions.

    • Constant menstrual-like cramping.

    • Low back pain.

    • Mucous or bloody vaginal discharge.

    • Bleeding or blood spotting after three months into the pregnancy.

Understanding Preterm Labor Symptoms

  • Symptoms of preterm labor serve as warning signs but do not necessarily indicate that preterm birth is unavoidable.

  • Research indicates that among women who consult a healthcare professional regarding preterm contractions prior to 37 weeks without preterm premature rupture of membranes (pPROM), about half will deliver at full term.

Premature Rupture of Membranes (PROM)

  • PROM refers to the rupture of the amniotic sac, creating a leakage or flood of amniotic fluid; when this occurs prior to the onset of contractions, it is designated as premature rupture of membranes (PROM).

  • When it occurs before 37 weeks, it is specified as preterm premature rupture of membranes (pPROM).

Evaluating Preterm Labour

  • Assessment involves:

    • Conducting a pelvic exam to determine if the cervix has effaced (thinned) and dilated (opened).

    • Monitoring uterine activity to detect contractions.

    • Fetal monitoring to check the health of the baby.

    • Performing a biochemical test that measures fetal fibronectin levels.

Women at Risk of Preterm Labor

  • Factors that elevate risk include:

    • History of previous preterm labor or early birth.

    • Smoking, drug use, or alcohol use during pregnancy.

    • Multiples pregnancies such as carrying twins or more.

    • Maternal age less than 16 or greater than 35 years.

    • Presence of complications such as pre-eclampsia or incompetent cervix (possibly due to vaginal infections).

    • Experience of stressful events or having a short interval between pregnancies.

Additional Factors Contributing to Preterm Labor

  • Problems may arise within the mother's womb itself, such as an inadequate placenta that fails to support the baby through to full term (e.g., placenta previa).

  • Chronic maternal conditions like diabetes, heart disease (e.g., congestive heart failure), or high blood pressure can increase the likelihood of early delivery.

  • Certain infections in the mother, such as genital herpes or syphilis, may also lead to premature births.

  • Placental abruption, which denotes the early separation of the placenta from the uterus,

  • The presence of maternal infections.

  • Employing assisted reproductive technology can yield higher rates of high-risk pregnancies, particularly those involving multiples (twins or more).

Preventing Preterm Labour

  • Approaches to prevent preterm labor include:

    • Tocolysis: A method aimed at inhibiting uterine contractions.

    • Administration of Ferring’s atosiban, which effectively works with the natural processes of labor to counter the action of oxytocin, thereby aiding in switching off contractions throughout the uterus, with an excellent safety profile.

    • Comprehensive prenatal care.

  • Administering corticosteroids over a 24-hour period can mature the fetus’s lungs; this treatment is regarded as the most effective intervention for preventing complications related to prematurity.

  • Infection prevention or treatment with antibiotics is critical, especially if the amniotic sac has ruptured, significantly increasing the risk of infection, thus necessitating close monitoring.

Conclusion and Future Approaches

  • Continued research is imperative to:

    • Define the etiology of preterm birth.

    • Identify interventions that may lessen the incidence of preterm births.

  • Strategies should strive to allow pregnant women to get as close to 40 weeks as possible before delivering to optimize the chances of having a healthy baby.

  • There is a need to identify women at high risk of early labor and to employ medications to inhibit premature delivery before it commences.