History

Fact Explanation
Extension of pregnancy beyond 42 weeks Usually pregnancy continues for 40 weeks of period of gestation and more than 40 weeks is called past dates. Post term pregnancy is the pregnancy that extends to 42 weeks and beyond. [4] Post term pregnancy is associated with an increased risk of fetal, maternal and neonatal mortality and morbidity. [4] There will be genetic predisposition and ethnic variation in the impact of the post-term. eg:-Asians placental aging happens relatively early therefore perinatal mortality may rise.
Parity Primiparity is a risk factor. [6]
History of previous postterm pregnancy Prior post term pregnancy is a risk factor for the post term pregnancy. [7]
Perinatal complications Increased perinatal mortality is a recognized complication of post-term pregnancy. Perinatal mortality ( stillbirths plus early neonatal deaths) at 42 weeks of gestation is twice that at 40 weeks which rises to 4-fold at 43 weeks. [2,3]
Antenatal fetal complications Antepartum stillbirth rate is higher in post partum pregnancy. [4]
Prematurity Is a known complication of post-term pregnancy. [5]
Pronged labour Post-term pregnancies are associated with fetal macrosomia, which predispose to other complications such prolonged labor, cephalopelvic disproportion, and shoulder dystocia. [6]
Shoulder dystocia [1] Shoulder dystocia is a dangerous complication occurring due to the macrosomia. Studies have shown that half of the shoulder dystocia [1] happen to macrosomic infants and recurrence of shoulder dystocia in subsequent deliveries.
Maternal complications during the delivery Perineal injury [6] (3rd and 4th degree perineal lacerations) may be due to fetal macrosomia, there is high risk of operative vaginal delivery.
References
  1. MOHAMMADBEIGI A, FARHADIFAR F, SOUFI ZADEH N, MOHAMMADSALEHI N, REZAIEE M, AGHAEI M. Fetal Macrosomia: Risk Factors, Maternal, and Perinatal Outcome Ann Med Health Sci Res [online] 2013, 3(4):546-550 [viewed 26 July 2014] Available from: doi:10.4103/2141-9248.122098
  2. HUSSAIN ARWA ABBAS, YAKOOB MOHAMMAD YAWAR, IMDAD AAMER, BHUTTA ZULFIQAR A. Elective induction for pregnancies at or beyond 41 weeks of gestation and its impact on stillbirths: a systematic review with meta-analysis. Array [online] 2011 December [viewed 20 August 2014] Available from: doi:10.1186/1471-2458-11-S3-S5
  3. WHITWORTH M, BRICKER L, NEILSON JP, DOWSWELL T. Ultrasound for fetal assessment in early pregnancy Cochrane Database Syst Rev [online] :CD007058 [viewed 20 August 2014] Available from: doi:10.1002/14651858.CD007058.pub2
  4. GALAL M, SYMONDS I, MURRAY H, PETRAGLIA F, SMITH R. Postterm pregnancy Facts Views Vis Obgyn [online] 2012, 4(3):175-187 [viewed 20 August 2014] Available from: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3991404
  5. IWANICKI S, AKIERMAN A. The Management of Post-Term Pregnancy Can Fam Physician [online] 1988 Sep:2027-2029 [viewed 18 September 2014] Available from: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2219142
  6. CAUGHEY AB, STOTLAND NE, WASHINGTON AE, ESCOBAR GJ. Maternal Complications of Pregnancy Increase Beyond 40 Weeks' Gestation Am J Obstet Gynecol [online] 2007 Feb, 196(2):155.e1-155.e6 [viewed 18 September 2014] Available from: doi:10.1016/j.ajog.2006.08.040
  7. EL MARROUN H., ZEEGERS M., STEEGERS E. A., VAN DER ENDE J., SCHENK J. J., HOFMAN A., JADDOE V. W., VERHULST F. C., TIEMEIER H.. Post-term birth and the risk of behavioural and emotional problems in early childhood. International Journal of Epidemiology [online] December, 41(3):773-781 [viewed 18 September 2014] Available from: doi:10.1093/ije/dys043

Examination

Fact Explanation
Greater fundal height Fundal height is more than corresponding height for period of gestation. Some may have reduced fundal height if complicated with oligohydrmnios. [4]
Birth weight more than 4kg / low birth weight Macrosomia is birth weight greater than either 4kg. [1] Intrauterine growth restriction (IUGR) is known to be associated with placental insufficiency. [3]
Hyperthermia and hypothermia of the newborn Intrauterine infection [5] is associated with post-term pregnancy.
Nerve injuries and fractures of the newborn Fetal macrosomia predispose to shoulder dystocia with associated nerve palsies of the baby occurring during the delivery of large baby. Damaged to the lower roots of brachial plexus [1] causes Klumpke's paralysis with paralysis of intrinsic muscles of the hand. Erb's palsy causes Facial nerve palsy is another complication. Bone fractures [1] Clavicle, humerus are the frequent bones to be fractured during the delivery.
Respiratory distress in the newborn May be due uteroplacental insufficiency and asphyxia. [2] Cardiorespiratory problems can be frequently seen among macrosomic babies.
Low 5-minute Apgar scores Strength and regularity of heart rate, lung maturity, muscle tone, skin colour and reflex response to irritable stimuli are the 5 components measured in the apgar score. Apgar score of 7 or above is normal, below 7 indicate some fetal distress and need for resuscitation. [6]
Pre-gestational maternal obesity Is a risk factor for fetal macrosomia. Obesity, is defined as Body Mass Index (BMI) equal or over 30 Kg/m2. [2] High Body mass index of the mother is an indication for the risk of large baby. [1]
References
  1. MOHAMMADBEIGI A, FARHADIFAR F, SOUFI ZADEH N, MOHAMMADSALEHI N, REZAIEE M, AGHAEI M. Fetal Macrosomia: Risk Factors, Maternal, and Perinatal Outcome Ann Med Health Sci Res [online] 2013, 3(4):546-550 [viewed 26 July 2014] Available from: doi:10.4103/2141-9248.122098
  2. HUSSAIN ARWA ABBAS, YAKOOB MOHAMMAD YAWAR, IMDAD AAMER, BHUTTA ZULFIQAR A. Elective induction for pregnancies at or beyond 41 weeks of gestation and its impact on stillbirths: a systematic review with meta-analysis. Array [online] 2011 December [viewed 20 August 2014] Available from: doi:10.1186/1471-2458-11-S3-S5
  3. GALAL M, SYMONDS I, MURRAY H, PETRAGLIA F, SMITH R. Postterm pregnancy Facts Views Vis Obgyn [online] 2012, 4(3):175-187 [viewed 20 August 2014] Available from: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3991404
  4. IWANICKI S, AKIERMAN A. The Management of Post-Term Pregnancy Can Fam Physician [online] 1988 Sep:2027-2029 [viewed 18 September 2014] Available from: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2219142
  5. WOLF H, SCHAAP AH, SMIT BJ, SPANJAARD L, ADRIAANSE AH. Liberal diagnosis and treatment of intrauterine infection reduces early-onset neonatal group B streptococcal infection but not sepsis by other pathogens. Infect Dis Obstet Gynecol [online] 2000, 8(3-4):143-150 [viewed 18 September 2014] Available from: doi:10.1155/S1064744900000181
  6. EHRENSTEIN V, PEDERSEN L, GRIJOTA M, NIELSEN GL, ROTHMAN KJ, SøRENSEN HT. Association of Apgar score at five minutes with long-term neurologic disability and cognitive function in a prevalence study of Danish conscripts BMC Pregnancy Childbirth [online] :14 [viewed 18 September 2014] Available from: doi:10.1186/1471-2393-9-14

Differential Diagnoses

Fact Explanation
Diabetes Mellitus GDM (Gestational Diabetes Mellitus) is defined as any degree of intolerance to glucose which is first recognized during pregnancy. [1] Risk factors for the development of GDM are age more than 35 years, pregestational maternal obesity, past history of GDM, family history of diabetes mellitus previous stillbirths.
Other causes for fundus larger than for dates Wrong dates may be a reason. [2] Therefore accurate last menstrual period is important to know. Dating scan should be done at around 11-14 weeks of gestation when it is more accurate. Occasionally pelvic tumours [3] or any pelvic lumps can give larger fundal height.
References
  1. CAPULA C, CHIEFARI E, VERO A, ARCIDIACONO B, IIRITANO S, PUCCIO L, PULLANO V, FOTI DP, BRUNETTI A, VERO R. Gestational Diabetes Mellitus: Screening and Outcomes in Southern Italian Pregnant Women ISRN Endocrinol [online] :387495 [viewed 26 July 2014] Available from: doi:10.1155/2013/387495
  2. IWANICKI S, AKIERMAN A. The Management of Post-Term Pregnancy Can Fam Physician [online] 1988 Sep:2027-2029 [viewed 18 September 2014] Available from: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2219142
  3. HORROCKS P. Pelvic Tumour Complicating Pregnancy Br Med J [online] 1886 Mar 6, 1(1314):441-442 [viewed 18 September 2014] Available from: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2256867

Investigations - for Diagnosis

Fact Explanation
Ultrasound scan Antenatal fetal surveillance is indicated between 40 and 42 weeks. Early pregnancy ultrasonographic dating is important to assess the expected date of delivery. First trimester ultrasound between 11 and 14 weeks, is more accurate than last menstrual period in assessing the EDD. [1] Anencephaly is also occurred in increased frequency in these pregnancies. Assessment of amniotic fluid volume, estimated fetal . No proven benefit of routine monitoring the post-term fetus with Doppler velocimetry.
Cardiactocography (CTG) Is done when there is suspicion about the fetal well being. [2] Absence of accelerations, presence of decelerations, and reduced variability are found in fetal distress.
References
  1. WHITWORTH M, BRICKER L, NEILSON JP, DOWSWELL T. Ultrasound for fetal assessment in early pregnancy Cochrane Database Syst Rev [online] :CD007058 [viewed 20 August 2014] Available from: doi:10.1002/14651858.CD007058.pub2
  2. IWANICKI S, AKIERMAN A. The Management of Post-Term Pregnancy Can Fam Physician [online] 1988 Sep:2027-2029 [viewed 18 September 2014] Available from: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2219142

Investigations - Fitness for Management

Fact Explanation
Haemoglobin If there is anaemia it should be corrected before the delivery. [3]
Blood grouping and Rh typing Rh negative previously unsentizised mothers should receive rhogum after delivery.[2]
Oral glucose toleranse test/post prandial blood sugar [1] Suspected fetal macrosomia may be due to the gestational diabetes mellitus. [1]
References
  1. ZECK W, SCHLEMBACH D, PANZITT T, LANG U, MCINTYRE D. Management of Diabetes in Pregnancy: Comparison of Guidelines with Current Practice at Austrian and Australian Obstetric Center Croat Med J [online] 2007 Dec, 48(6):831-841 [viewed 26 July 2014] Available from: doi:10.3325/cmj.2007.6.831
  2. CACCIATORE A, RAPITI S, CARRARA S, CAVALIERE A, ERMITO S, DINATALE A, IMBRUGLIA L, RECUPERO S, LA GALIA T, PAPPALARDO EM, ACCARDI MC. Obstetric management in Rh alloimmunizated pregnancy J Prenat Med [online] 2009, 3(2):25-27 [viewed 18 September 2014] Available from: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3279102
  3. BAROOTI E, REZAZADEHKERMANI M, SADEGHIRAD B, MOTAGHIPISHEH S, TAYERI S, ARABI M, SALAHI S, HAGHDOOST AA. Prevalence of Iron Deficiency Anemia among Iranian Pregnant Women; a Systematic Review and Meta-analysis J Reprod Infertil [online] 2010, 11(1):17-24 [viewed 27 July 2014] Available from: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3719272

Investigations - Followup

Fact Explanation
Modifiec biophysical profile (nonstress test and amniotic fluid volume ) Monitoring may be twice-weekly with assessing the amniotic fluid volume beginning at 41 weeks of gestation. A nonstress test and amniotic fluid volume assessment is usually sufficient. [1,2]
References
  1. WHITWORTH M, BRICKER L, NEILSON JP, DOWSWELL T. Ultrasound for fetal assessment in early pregnancy Cochrane Database Syst Rev [online] :CD007058 [viewed 20 August 2014] Available from: doi:10.1002/14651858.CD007058.pub2
  2. CZERESNIA JM, ARAUJO JúNIOR E, CORDIOLI E, MARTINS WP, NARDOZZA LM, MORON AF. Applicability of the Rapid Biophysical Profile in Antepartum Fetal Well-Being Assessment in High-Risk Pregnancies from a University Hospital in S?o Paulo, Brazil: Preliminary Results ISRN Obstet Gynecol [online] :329542 [viewed 20 August 2014] Available from: doi:10.1155/2013/329542

Investigations - Screening/Staging

Fact Explanation
Ultrasound scan [1] Anancephaly is more frequent in these fetuses. Thereore anomaly scan is important to perform. [1]
Doppler studies There can be placental insufficiency that can cause fetal compromise. Blood flow velocity waveforms are recorded from the umbilical arteries, the middle cerebral artery, and the descending thoracic aorta. Resistance index and pulsatility index is also measured. Absent or reverse end-diastolic flow in the umbilical artery is an indicator of fetal compromise. [2] Doppler studies are repeated at intervals not less than 2 weeks.
References
  1. WHITWORTH M, BRICKER L, NEILSON JP, DOWSWELL T. Ultrasound for fetal assessment in early pregnancy Cochrane Database Syst Rev [online] :CD007058 [viewed 20 August 2014] Available from: doi:10.1002/14651858.CD007058.pub2
  2. HECHER K., CAMPBELL S., DOYLE P., HARRINGTON K., NICOLAIDES K.. Assessment of Fetal Compromise by Doppler Ultrasound Investigation of the Fetal Circulation : Arterial, Intracardiac, and Venous Blood Flow Velocity Studies. Circulation [online] 1995 January, 91(1):129-138 [viewed 26 July 2014] Available from: doi:10.1161/01.CIR.91.1.129

Management - General Measures

Fact Explanation
Antenatal fetel monitoring Regular monitoring of fetal well being using cardiotocograph (CTG) and amniotic fluid index (AFI) [3] is advised beyond 41 weeks.
Normal vaginal delivery Special attention is needed in post-term pregnancy as these mothers and their fetuses are at risk of birth trauma, shoulder dystosia, brachial plexus injuries, fetal death and poor progression of labour, low Apgar scores, macrosomia, meconium aspiration syndrome and cesarean delivery. [1,2] Experienced persons should attend the delivery. First stage and second stage has to be monitored to detect complications such as poor progression of labour. Partogram has to be carefully maintained to detect poor progression. Vaginal birth after cesarean section (VBAC) is less likely to succeed if the baby is macrosomic. [1]
Avoidance of a post term pregnancypregnancy High risk groups such a those with primiparity, history of and previous post-term pregnancy, placental sulfatase deficiency, fetal anencephaly, and male sex have been associated with prolongation of pregnancy, and genetic predisposition may need early elective induction can be carried out. [2]
References
  1. CHENG Y, SPARKS T, LAROS R JR, NICHOLSON J, CAUGHEY A. Impending macrosomia: will induction of labour modify the risk of caesarean delivery? BJOG [online] 2012 Mar, 119(4):402-409 [viewed 26 July 2014] Available from: doi:10.1111/j.1471-0528.2011.03248.x
  2. FARQUHARSON DF. Management of post-Date Pregnancy Can Fam Physician [online] 1986 Oct:2171-2176 [viewed 18 September 2014] Available from: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2328217
  3. IWANICKI S, AKIERMAN A. The Management of Post-Term Pregnancy Can Fam Physician [online] 1988 Sep:2027-2029 [viewed 18 September 2014] Available from: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2219142

Management - Specific Treatments

Fact Explanation
Management options Elective induction of labor and expectant management of the pregnancy [3] are the options available for the management. Gestational age, condition of the cervix, results of antepartum fetal testing, and maternal preference are the factors considered in the decision making. Options should be discussed with the mother and her preference also needs to be considered.
Induction of labour [1] There is an increased risk of perinatal death and birth injury beyond 42 weeks' gestation which makes the decision to induce the labour in post-term pregnancies at 41+0 to 42+0 weeks. Cervical examination is done and if the cervix is favourable it is better to induce as the risk of failed induction and subsequent cesarean delivery is low with induction of the labour. In unfavorable cervices, there is slight advantage of labour induction using cervical-ripening agents. Cervical ripening is done using either surgical or medical methods. Arteficial separation of the membranes, foley catheters, prostaglandins are used for the ripening of the cervix. Prostaglandins should be used carefully in low doses as there is an increased risk of uterine tachysystole and hyperstimulation. When prostaglandin is used, fetal heart rate monitoring is important to detect the fetal compromise. [2]
Expectant management Elective induction of labour has shown to reduce the incidence of meconium aspiration syndrome and macrosomia with no difference in birth asphyxia. [1] Expectant management may also be disadvantageous in high risk mothers with co-morbities. [2,3]
References
  1. HUSSAIN ARWA ABBAS, YAKOOB MOHAMMAD YAWAR, IMDAD AAMER, BHUTTA ZULFIQAR A. Elective induction for pregnancies at or beyond 41 weeks of gestation and its impact on stillbirths: a systematic review with meta-analysis. Array [online] 2011 December [viewed 20 August 2014] Available from: doi:10.1186/1471-2458-11-S3-S5
  2. GALAL M, SYMONDS I, MURRAY H, PETRAGLIA F, SMITH R. Postterm pregnancy Facts Views Vis Obgyn [online] 2012, 4(3):175-187 [viewed 20 August 2014] Available from: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3991404
  3. CAUGHEY AB, STOTLAND NE, WASHINGTON AE, ESCOBAR GJ. Maternal Complications of Pregnancy Increase Beyond 40 Weeks' Gestation Am J Obstet Gynecol [online] 2007 Feb, 196(2):155.e1-155.e6 [viewed 18 September 2014] Available from: doi:10.1016/j.ajog.2006.08.040