What is the goal of perinatal care?

  • The care of women and fetus or newborn given; before, during, and after delivery; from the 28th week of gestation through the seventh day after delivery

  • Fetal health

  • Recognizing diseases and intrauterine treatment

  • First trimester fetal life, detecting major anomalies

  • Second trimester congenital anomalies, syndromes, toxic effects

  • Third trimester fetal well-being

Which methods are being used for perinatal care?

  • Non-stress test (NST)

  • Contraction stress test (CST)

  • Fetal biophysics profile (BPP)

  • Amniotic fluid index (AFI)

  • Doppler ultrasound

  • Counting of fetal movements (kick counting)

Why is perinatal care important?

  • Fetal death is seen in 1% of all third trimester low-risk pregnancies without routine perinatal care.

  • Two thirds of deaths are intrauterine, and this rate increases especially in high-risk patients.

Which pregnancies are considered as high-risk pregnancies in the aspect of uteroplacental insufficiency?

  • Prolonged pregnancy

  • Diabetes mellitus (DM)

  • Hypertension (HT)

  • Isoimmunization

  • Stillbirth in previous pregnancies

  • Intrauterine growth restriction (IUGR)

  • Advanced mother age

  • Discordant multiple pregnancy, as in twin-to-twin transfusion syndrome (TTTS)

  • Antiphospholipid syndrome (APS)

Describe the role of non-stress test (NST) in perinatal care

  • A good test interpreted as reactive. There should be:

    • At least two fetal movements

    • At the same time two accelerations lasting 15 s and not less than 15 beats/min in 20 min of monitoring for reactivity

  • Fetal heart rate: 120–160/min

  • In some fetuses, 110–120/min fetal heart beats can also be considered as normal

  • May be physiologically non-reactive NST before 30th gestational week

What is the role of the stress test (CST) in evaluating fetal well-being?

  • It is the most precious test for the evaluation of fetal well-being.

  • Blood flow to intervillous area decreases during uterine contractions.

  • Blood supply decreases up to 30%.

  • If there is no placental insufficiency, the baby responds to it as acceleration.

  • Responds as deceleration if there is insufficiency.

How would you apply contraction stress test (CST)?

  • Test is done by creating contractions, three contractions within 10 min.

  • Oxytocin is given to form contraction, or nipple stimulation.

  • Should be laid semi-Fowler and 30–45° lateral position to avoid supine hypotension.

  • The CST is used for its high negative predictive value.

What is the meaning of positive CST?

  • Late decelerations present with more than half of the uterine contractions. Generally it shows placental respiratory insufficiency is present.

What is the meaning of negative CST?

  • No late deceleration presents with adequate uterine contractions present. Generally marker of fetal well-being.

What are the contraindications of contraction stress test (CST)?

  • It should not be done to patients who are at risk of premature birth.

  • Premature rupture of membranes (PROM).

  • Multiple pregnancy.

  • Pregnant with vaginal bleeding.

  • Cervical cerclage.

  • Preterm labor.

  • Placenta previa or ablation placenta.

  • Patients who previously had C/S with vertical (classical uterine) incision.

  • Previous history of myomectomy.

What are the evaluation criteria of CST?

Comment

Criteria

Incidence (%)

Negative

3 contractions/10 min

No deceleration

80

Positive

Deceleration with 50% contraction

3–5

Suspicious

Temporary deceleration

5

Hyperstimulation

More than 5 times deceleration with contraction in 10 min

5

Insufficient

Fewer than three contractions occur within 10 minutes, or quality of tracing is inadequate for accurate interpretation. Repeat test on the following day.

5

What are the parameters of fetal biophysical profile (BPP) evaluation?

Parameter

Normal (2 points)

Abnormal (0 point)

NST

Reactive

Non-reactive

Fetal respiration

Lasting for 30 s at 30 m

No movement or less than 30 s

Movement

At least three fetal movement

Reduced movements

Tonus

Extension, flexion

Opening and closing of hands

Continuous extension and open fingers

Amnion fluid

At least 2 cm of pocket in two planes

Less fluid

  • If the score is 10, probability of fetal death in 2 weeks is 0%.

  • If the score is 0, probability of fetal death is around 60%.

What are the parameters in the modified fetal biophysical profile (BPP)?

  • NST and Amniotic fluid index (AFI) measurements: also indicators for fetal well-being.

What are the features of the amniotic fluid volume?

  • 200 mL at 16th week.

  • 1000 mL at the beginning of the third trimester.

  • Weekly decreases by 150 mL after 38 weeks.

  • Renewed about 95% per day.

  • It is directly related to uteroplacental blood flow.

  • If uteroplacental blood flow decreases, fetal renal blood flow and fetal renal glomerular filtration rate (GFR) also decreases so oligohydramnios occurs.

  • It is the sum of the deepest pockets on the four uterine quadrants.

  • Perinatal mortality and morbidity increased in patients with Amniotic fluid index (AFI) below 5 cm.

How would you advise your patient to count fetal movements?

  • Fetal movements/kicks indicate fetal well-being.

  • Fetal movements may decrease due to the decrease of amnion fluid in the third trimester.

  • Fetal movements should be at least 10 per day.

Which vessels are measured by Doppler velocimetry?

  • Uterine artery

  • Umbilical artery

  • Fetal middle cerebral artery (MCA)

  • Umbilical vein

  • Ductus venosus (DV)

What are the characteristics of Doppler measurement?

  • Ultrasound sound waves hit the blood, and moving elements like erythrocytes turn back those waves.

  • Frequencies of the outgoing sound waves and returning sound waves are different.

  • This is called the Doppler effect, and the frequency change is called the Doppler frequency.

  • Blood flow in the ultrasound is measured by measuring the movement of blood flow.

  • A sound wave is sent from the transducer to capture blood flow.

  • The echoes obtained from the fixed tissues through which the sound wave passes are always the same.

  • Echoes obtained from moving tissues such as blood vary according to the return of the signal to the recipient.

Which Doppler indexes are used during pregnancy?

  • Systole/diastole (A/B).

  • Pulsatility index (S-D/mean).

    It is difficult to calculate, but it is the most reliable measurement in very small vessels or vessels without diastole flow. It can be easily calculated.

  • Resistance index (S-D/S).

Relationship between fetal circulation and Doppler ultrasound?

  • Diastole flow of umbilical artery increases near term.

  • High S/D ratio is a very important parameter in IUGR.

  • Excessively affected fetuses do not have diastolic flow or have reverse flow.

Explain the importance of Doppler measurement for ductus arteriosus.

  • Doppler measurement of Ductus arteriosus should be considered as primary in the use of indomethacin and other nonsteroidal anti-inflammatory drugs, due to the side effect of the prostaglandin inhibitors (PGI) that is early closure of ductus arteriosus. Indomethacin is used for tocolysis and in the treatment of polyhydramnios.

  • Indomethacin causes constriction at ductus arteriosus, to increase in pulmonary flow and reactive pulmonary arteriolar hypertrophy; pulmonary hypertension.

  • If the medication is discontinued before 32nd week, this condition is resolved.

In which case is Doppler measurement of the mid cerebral artery (MCA) used?

  • Peak systolic velocity (PSV) increases (>1.5 MoM) in case of fetal anemia—due to increased cardiac output and decreased blood viscosity.

  • MCA/placental blood flow rate may be used depending on the brain protective effect in the presence of fetal hypoxemia.

In which situations uterine artery Doppler measurement is used?

  • In normal pregnancy, uterine blood flow increases from 50 mL/min to 500–700 mL/min.

  • Uterine blood flow is characterized by high diastolic blood flow.

  • Increased resistance and presence of diastolic notch indicate hypertension.

  • Pregnancies that will develop HT or preeclampsia may be predicted in Doppler measurements performed at 16–20th gestational ages.

What is the most valuable test for evaluating fetal well-being?

  • CST

What is the mechanism of late deceleration in NST or CST?

  • In fetuses with reduced oxygen reserve, periodic decreases in oxygen during contractions reach the critical level, which trigger the carotid chemoreceptors. As a reflex, an alpha sympathetic response that constricts the low-resistance arterial bed is initiated. This results in a systemic arterial hypertension that causes the baroreceptors to produce a vagal response that slows down the fetal heart rate and is seen as a late deceleration.