Author's details
Reviewer's details
Post Term Pregnancy
Post Term Pregnancy is a pregnancy that extends to 42 weeks of gestation or beyond. It can also be referred to as prolonged pregnancy. It is not clearly understood why some women have post term pregnancies but factors including obesity, hormonal and genetic factors have been implicated. However, the actual biologic variation is likely less, because the most frequent cause of a post-term pregnancy diagnosis is inaccurate dating. Usually, the estimated gestational age is calculated using the first day of the last menstrual period, it must however, be noted that in patients with cycle length greater than 28days, using the same calculation may give error. Therefore, the regularity and length of the cycle must be considered when estimating the gestational age. It is associated with increased risk of morbidity and mortality to the fetus. The incidence of post term pregnancy is about 5-10% of all pregnancies.
- Primiparity
- Previous post term pregnancy
- Male fetus
- Anencephaly
- Fetal adrenal insufficiency
- Obesity
- Placental sulphatase deficiency
Features seen in post term babies include thin wrinkled peeling skin (excessive desquamation), thin body (malnourishment), long hair and nails, oligohydramnios and frequently passage of meconium. These pregnancies are at increased risk of umbilical cord compression from oligohydramnios, meconium aspiration, and short-term neonatal complications such as hypoglycemia, seizures, and respiratory insufficiency. They also have an increased incidence of non-reassuring antepartum and intrapartum fetal testing
This includes labor dystocia, prolonged labor, severe perineal lacerations, operative vaginal delivery, postpartum hemorrhage from perineal injuries and deliveries of macrosomic babies and increased Caesarean section rates, cephalo-pelvic disproportion
This includes meconium aspiration syndrome, macrosomia, fetal dysmaturity syndrome from placental insufficiency, antepartum stillbirth, low APGAR score, Birth injuries, and shoulder dystocia.
In managing prolonged pregnancy, the first decision is whether to deliver or not, the risk of continuing the pregnancy should be weighed against benefit of ending the pregnancy. Factors such as the fetal condition, estimated gestational age, liquor volume, any maternal co-morbidity and the wish of the woman should be considered.
The management options include Expectant management with continuous fetal surveillance, Induction of Labor and caesarean delivery can be considered. In any chosen option the safety of the baby and mother must be a priority.
- Accurate pregnancy dating is crucial to the diagnosis and management of post term pregnancy. Last menstrual period has traditionally been used to calculate the expected date of delivery (EDD)
- Studies have shown routine early and first trimester ultrasound examination for pregnancy dating resulted in a reduction in the overall rate of post term pregnancy from about 10-15% to approximately 2-5%, and thereby minimized unnecessary intervention
- Membrane sweeping or stripping which is the digital separation of the membranes from the cervix and lower uterine segment helps release some endogenous prostaglandins and may start off the process of labor. This can be done at 40weeks gestation and has been shown to reduce the risk of post-term pregnancy.
- Local management practices such as scheduled IOL, the use of early ultrasound (US) for accurate dating of pregnancy, and elective Caesarean section (CS) rates will affect the overall prevalence of post term pregnancy.
A 32-year-old woman, gravida 2 para 1, presents at 42 weeks gestation without labor symptoms. Her first pregnancy ended in an uncomplicated vaginal delivery at 39 weeks. She is now concerned about the prolonged pregnancy. Examination shows normal fetal movement and heart rate, but decreased amniotic fluid on ultrasound. The healthcare team discusses the need for labor induction due to risks associated with post-term pregnancy. A 32-year-old woman, gravida 2 para 1, presents at 42 weeks gestation without labor symptoms. Her first pregnancy ended in an uncomplicated vaginal delivery at 39 weeks. She is now concerned about the prolonged pregnancy. Examination shows normal fetal movement and heart rate, but decreased amniotic fluid on ultrasound. The healthcare team discusses the need for labor induction due to risks associated with post-term pregnancy.
- Galal M, Symonds I, Murray H, Petraglia F, Smith R. Postterm pregnancy. Facts Views Vis Obgyn. 2012;4(3):175-87. PMID: 24753906; PMCID: PMC3991404.
- Royal College of Obstetricians and Gynaecologists. Shoulder Dystocia (Green-top Guideline No. 42). 2017 https://www.rcog.org.uk/globalassets/documents/guidelines/gtg_42.pdf (accessed 12.11.2021).
- Davis DD, Roshan A, Varacallo M. Shoulder Dystocia. [Updated 2023 Dec 20]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2024 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK470427/
Author's details
Reviewer's details
Post Term Pregnancy
Post Term Pregnancy is a pregnancy that extends to 42 weeks of gestation or beyond. It can also be referred to as prolonged pregnancy. It is not clearly understood why some women have post term pregnancies but factors including obesity, hormonal and genetic factors have been implicated. However, the actual biologic variation is likely less, because the most frequent cause of a post-term pregnancy diagnosis is inaccurate dating. Usually, the estimated gestational age is calculated using the first day of the last menstrual period, it must however, be noted that in patients with cycle length greater than 28days, using the same calculation may give error. Therefore, the regularity and length of the cycle must be considered when estimating the gestational age. It is associated with increased risk of morbidity and mortality to the fetus. The incidence of post term pregnancy is about 5-10% of all pregnancies.
- Galal M, Symonds I, Murray H, Petraglia F, Smith R. Postterm pregnancy. Facts Views Vis Obgyn. 2012;4(3):175-87. PMID: 24753906; PMCID: PMC3991404.
- Royal College of Obstetricians and Gynaecologists. Shoulder Dystocia (Green-top Guideline No. 42). 2017 https://www.rcog.org.uk/globalassets/documents/guidelines/gtg_42.pdf (accessed 12.11.2021).
- Davis DD, Roshan A, Varacallo M. Shoulder Dystocia. [Updated 2023 Dec 20]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2024 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK470427/
Content
Author's details
Reviewer's details
Post Term Pregnancy
Background
Post Term Pregnancy is a pregnancy that extends to 42 weeks of gestation or beyond. It can also be referred to as prolonged pregnancy. It is not clearly understood why some women have post term pregnancies but factors including obesity, hormonal and genetic factors have been implicated. However, the actual biologic variation is likely less, because the most frequent cause of a post-term pregnancy diagnosis is inaccurate dating. Usually, the estimated gestational age is calculated using the first day of the last menstrual period, it must however, be noted that in patients with cycle length greater than 28days, using the same calculation may give error. Therefore, the regularity and length of the cycle must be considered when estimating the gestational age. It is associated with increased risk of morbidity and mortality to the fetus. The incidence of post term pregnancy is about 5-10% of all pregnancies.
Further readings
- Galal M, Symonds I, Murray H, Petraglia F, Smith R. Postterm pregnancy. Facts Views Vis Obgyn. 2012;4(3):175-87. PMID: 24753906; PMCID: PMC3991404.
- Royal College of Obstetricians and Gynaecologists. Shoulder Dystocia (Green-top Guideline No. 42). 2017 https://www.rcog.org.uk/globalassets/documents/guidelines/gtg_42.pdf (accessed 12.11.2021).
- Davis DD, Roshan A, Varacallo M. Shoulder Dystocia. [Updated 2023 Dec 20]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2024 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK470427/
Advertisement