What is the evaluation for labor in a high-risk pregnancy at 36 weeks gestational age?

From the Guidelines

Evaluation of labor in a high-risk 36-week gestational age pregnancy should prioritize fetal well-being and maternal health, with a comprehensive assessment in a hospital setting, including continuous fetal monitoring and ultrasound evaluation, as recommended by the Society for Maternal-Fetal Medicine 1. To evaluate labor in a high-risk 36-week gestational age pregnancy, the following steps should be taken:

• Begin with a thorough maternal history review focusing on the specific high-risk factors, followed by a complete physical examination including vital signs, abdominal examination, and cervical assessment.
• Electronic fetal monitoring should be initiated promptly to evaluate fetal heart rate patterns and detect any signs of distress, as recommended by the Society for Maternal-Fetal Medicine 1.
• Laboratory tests including complete blood count, comprehensive metabolic panel, and coagulation studies should be obtained to assess maternal health and identify any potential complications.
• Ultrasound assessment is essential to confirm fetal presentation, estimate fetal weight, assess amniotic fluid volume, and evaluate placental location and function, as outlined in the Society for Maternal-Fetal Medicine guidelines 1.
• Contraction monitoring via tocodynamometer will help determine if true labor is occurring.
• Administer antenatal corticosteroids (betamethasone 12mg IM, two doses 24 hours apart) if not previously given, to accelerate fetal lung maturity, as recommended by the Society for Maternal-Fetal Medicine 1.
• Group B Streptococcus prophylaxis with penicillin G 5 million units IV initial dose, then 2.5-3 million units every 4 hours until delivery should be administered if status is positive or unknown.
• The decision for delivery versus expectant management should be based on the specific high-risk condition, maternal status, fetal wellbeing, and gestational age, with the understanding that at 36 weeks, many fetuses have adequate lung maturity but may still benefit from additional time in utero if both mother and fetus are stable, as suggested by the Society for Maternal-Fetal Medicine guidelines 1. In cases of fetal growth restriction, delivery at 37 weeks of gestation is recommended in pregnancies with fetal growth restriction and an umbilical artery Doppler waveform with decreased diastolic flow but without absent/reversed end-diastolic velocity or with severe fetal growth restriction with estimated fetal weight less than the third percentile, as recommended by the Society for Maternal-Fetal Medicine 1.

From the Research

Evaluating Labor in High-Risk Pregnancy

To evaluate for labor in a high-risk 36-week gestational age pregnancy, several factors must be considered:

• The definition of a high-risk pregnancy, which is any unexpected or unanticipated medical or obstetric condition associated with a pregnancy with an actual or potential hazard to the health or well-being of the mother or fetus 2
• The use of tocolytic agents, such as beta2 sympathomimetic agonists, magnesium sulphate (MgSO4), indomethacin, nifedipine, and atosiban, to delay preterm labor 3
• The potential interactions between these agents and other medications, such as the coadministration of OBE022 with MgSO4, atosiban, nifedipine, and betamethasone 4
• The risk of developing pulmonary edema in women exposed to nifedipine, MgSO4, or both in a preterm setting, with MgSO4 treatment being strongly associated with the development of pulmonary edema 5

Tocolytic Agents and Their Effects

The available evidence shows that:

• Beta2 agents are effective but have significant maternal side effects and no effect on perinatal outcome 3
• MgSO4 and glyceryl trinitrate are clearly ineffective 3
• Nifedipine is effective with a low maternal side effect profile and is associated with improved perinatal outcomes 3
• Atosiban is no more effective than other tocolytic therapies 3

Considerations for High-Risk Pregnancy

In evaluating for labor in a high-risk 36-week gestational age pregnancy, it is essential to consider the potential risks and benefits of tocolytic agents and other medications, as well as the individual patient's medical history and obstetric conditions. The use of MgSO4, in particular, should be carefully considered due to its association with pulmonary edema 5.