Managing Post-Term Pregnancy

• The document discusses the management of pregnancies that go beyond the due date (dépassement de terme), providing educational objectives, prerequisites, a pretest with answers and detailed information on the topic.

Educational Objectives

• Confirming dépassement de terme.
• Differentiating between "terme avancé" (advanced term) and dépassement de terme.
• Explaining fetal risks associated with dépassement de terme.
• Evaluating the fetal impact of dépassement de terme.
• Planning the management (prise en charge) of dépassement de terme.
• Preventing dépassement de terme through patient education.

Prerequisites

• Understanding the physiology of fetal-placental exchanges.
• Monitoring of typical pregnancy.
• Understanding normal childbirth.

Definitions and Introduction

• Gestation typically lasts between 280 and 290 days from the first day of the last menstrual period (DDR).
• The due date corresponds to 41 weeks of amenorrhea (SA) to 41 weeks + 3 days.
• Term is defined as the period from 37 SA to 41 SA + 6 days.
• "Terme prolongé" (prolonged term, or advanced term) refers to pregnancies extending beyond 41 SA.
• Dépassement de terme is when the pregnancy reaches 42 SA (294 days).
• Prolonged pregnancies have identified risks for the baby, mandating special monitoring up to 42 SA and interventions to induce labor.
• Pregnancy should not exceed 294 days.

Risk Factors

• Exact cause is unknown.
• Any pregnant woman can experience dépassement de terme, but some are at higher risk:
• History of dépassement de terme.
• First pregnancy (Primiparité).
• BMI over 25.
• Trisomy 18.
• Anencephaly.
• Congenital adrenal hyperplasia.

Positive Diagnosis

• Calculating the term relies on clinical and paraclinical data.

Clinical Data

• Primarily based on the patient's history, focusing on the date of last menstrual period (DDR) and menstrual cycle characteristics.
• DDR is central to calculating gestational age in weeks of amenorrhea; cycle length and regularity should be considered.
• For women with regular cycles, term is typically set at 39 weeks post-ovulation, equivalent to 41 weeks after the last menstrual period.
• Irregular cycles increase the risk of overestimating gestational age, as days are added to the DDR, but ovulation occurs 14 days before menstruation.
• If the DDR is accurate by the patient and occurs on a typical 28-30 day cycle, without contraception or recent abortion/post-partum, it can be used.
• If these conditions aren't met, DDR-based dating can underestimate the gestational age, misclassifying pregnancies as post-term.

Ménothermic Curve

• This method is unreliable due to various factors like stress, irregular sleep, and illness.

Assisted Reproductive Technology

• Determining pregnancy start is easier with assisted reproductive technology.
• The date of ovulation induction, insemination, or embryo transfer is known.

Physical Exam

• Involves vaginal exam combined with abdominal palpation.
• Vaginal exam reveals an enlarged uterus palpable in the vaginal fornices.
• Historically uterus size was compared to fruits.
• Mandarin: 1 month.
• Orange: 2 months.
• Grapefruit 3 months
• physical exam could suspect the gestation based on the size of the uterus.

Biological Data

• Beta-hCG measurement is not helpful.

Obstetric Ultrasound

• Early ultrasound examination
• is the standard for accurately dating a pregnancy.
• Ultrasound between 7 and 14 SA can accurately determine gestational age by measuring crown-rump length (LCC).
• After 14 SA, fetal LCC variability increases and is not used for dating the pregnancy.

Second Trimester Ultrasound

• Up to 20 SA, the gestational age can be estimated by measuring the biparietal diameter (BIP) and femur length (LF).

Ultrasound After 26 SA

• Term determination becomes less accurate.
• Fetal biometry (BIP) offers information, but BIP becomes unreliable in cases of fetal macrosomia or intrauterine growth restriction (IUGR).
• After the first trimester, ultrasounds must be precise for assessment.
• Repetition of ultrasounds every 15 days is a means of making measurements more precise.
• Positive diagnosis of dépassement de terme relies on an accurate DDR and first-trimester ultrasound with LCC measurement between 7 and 14 SA.

Complications

• Complications differ based on the presence or absence of placental senescence.

Placental Senescence

• Placental apoptosis begins, and the placenta becomes less efficient, calcifies, and impairs maternal-fetal exchanges.
• The fetus experiences chronic fetal distress, redirecting blood to vital organs, resulting in renal and digestive hypoperfusion, leading to oligohydramnios, meconium emission, and fetal growth restriction.
• Severe exchange compromise can cause hypoxemia or asphyxia, risking fetal death in utero.

Before Delivery Complications

• Main complication is post-maturity syndrome, involving reduced fetal movements, oligohydramnios, and meconium in amniotic fluid.
• Restriction of growth.
• Oligoamnios.
• Cordon compression accidents.

During Delivery Complications

• Acute fetal distress.
• High rate of C-sections.

Post-Partum Complications

• Hypoglycemia risk from macrosomia, requires newborns to be monitored.
• Meconium aspiration syndrome is a high morbidity and mortality, increasing with gestational age (0.24% to 1.42% between 38+0 and 42+6 SA).
• Respiratory issues may present in 1.8-3.6% of newborns after 42 SA, potentially leading to death in 5-10% of cases.

Absence of Placental Senescence

• If placental senescence is absent, uteroplacental perfusion and fetal irrigation are maintained, potentially leading to:
• Risk of macrosomia.
• Traumatic childbirth.
• Frequent C-sections.

Management Guidelines

• Any pregnant woman who has not gone into labour by 41 SA should consult with a doctor.
• All should have maternal well-being, fetal well-being checked and a Bishop score assessed.
• If the maternal and fetal evaluations are normal at 41 SA, vaginal delivery is expected, and the Bishop score is unfavorable, monitoring may continue to maximum 42 SA, with the goal of awaiting spontaneous labor onset without increasing maternal/fetal morbidity.
• Between 41 and 42 SA the following conductions are advised:
• informing the woman in labour of the risks.
• Surveillance: Twice daily monitoring to identify fetal or maternal risks and assess Bishop scores will evaluate whether a woman should undergo a C-section.
• clinical checks.
• Includes maternal signs, uterine height, fetal movements etc.
• Paraclinical check includes a fetal heart rate and an ultrasound (Amniotic fluid and foetal biometry)

Delivery should occur:

• between 41 an 42 Weeks.
• Bishop scores should be looked at.
  • Favourable: Induction.
  • Unfavourable: cervical maturation.
• Caesarian should be performed for maternal or fetal emergency.
• Vaginal delivery should is monitored continuously using fetal monitoring. A pediatrician is mandatory if newborns are born and they are at risk.

Newborn

• Newborn Post-term syndrome is present in 10% of births at 42 Weeks and is characterised by
• Skin issues, they can be peels, cracked.
• Long nails.

Conclusion

• Dépassement de terme is a common situation with potential risks to fetal life.
• Diagnosis depends on knowing the precise gestational age with an LCC measurement before 14+0 SA.

Management

• With prolonged pregnancy, monitoring must start at 41+0 SA, repeated every 48 hours until delivery, to decide on labor induction or C-section for minimising fetal morbidity/mortality.

Post-test

• A post nature newborns typically shows dry skin, peelings with long nails.
• Post maturity syndrome is present if a fetus has less movement, Amniotic problems and growth issues.
• Macrosomia issues include Hypoglycaemia and mechanical dystocial events.