European Journal of Cardiovascular Medicine

Pregnancy is a physiological process with an expected duration of approximately 280 days or 40 weeks from the first day of the last menstrual period. However, when pregnancy extends beyond 42 completed weeks (294 days), it is termed as post-dated or post-term pregnancy. This condition affects approximately 5-10% of all pregnancies worldwide and represents a significant clinical challenge in modern obstetric practice.[1] The accurate determination of gestational age through first-trimester ultrasonography has reduced the incidence of diagnosed post-term pregnancies, yet it remains a common obstetric concern requiring careful management and surveillance.

The aetiology of post-dated pregnancy remains incompletely understood, though several factors have been implicated in its occurrence. Nulliparity, previous history of post-term pregnancy, genetic predisposition, and male fetal gender have been identified as potential risk factors.[2] Additionally, certain placental factors and fetal anomalies, particularly anencephaly and adrenal hypoplasia, have been associated with prolonged gestation. The fundamental physiological mechanisms that trigger the onset of labour remain elusive, making it challenging to predict or prevent post-term pregnancy in most cases. Understanding these underlying factors is crucial for developing appropriate screening and management protocols in institutions like Tezpur Medical College and Hospital.

Post-dated pregnancy poses substantial risks to both maternal and fetal health, making it a significant public health concern. The placenta, which functions optimally until approximately 40-41 weeks of gestation, may undergo degenerative changes beyond this period, leading to placental insufficiency.[3] This pathophysiological process results in decreased oxygen and nutrient transfer to the fetus, potentially causing fetal hypoxia, intrauterine growth restriction, and oligohydramnios. The progressive decline in placental function creates a hostile intrauterine environment that increases the risk of adverse perinatal outcomes. Fetal monitoring and assessment become critical components of management as pregnancy advances beyond term.

Perinatal mortality and morbidity increase significantly in post-term pregnancies, with studies demonstrating a two-fold increase in stillbirth rates beyond 42 weeks of gestation.[4] The mechanisms underlying this increased mortality include uteroplacental insufficiency, meconium aspiration syndrome, birth asphyxia, and umbilical cord complications. Meconium-stained amniotic fluid occurs more frequently in post-term pregnancies, reflecting fetal stress and maturation of the gastrointestinal system. When aspirated during delivery, meconium can cause severe respiratory complications requiring intensive neonatal care. The risk of meconium aspiration syndrome increases progressively with advancing gestational age, highlighting the importance of vigilant intrapartum monitoring.

Macrosomia, defined as birth weight exceeding 4000 grams, occurs with increased frequency in post-dated pregnancies, affecting approximately 10-20% of post-term deliveries.[5] Macrosomic fetuses are at higher risk of shoulder dystocia, birth trauma including brachial plexus injury, clavicular fractures, and cephalohematoma. For mothers, macrosomia increases the likelihood of operative vaginal delivery, caesarean section, perineal lacerations, and postpartum haemorrhage. The management of suspected macrosomia in post-term pregnancy presents a clinical dilemma, as ultrasound estimation of fetal weight has limited accuracy at term, and prophylactic caesarean delivery for suspected macrosomia remains controversial.

Maternal complications associated with post-dated pregnancy extend beyond delivery-related morbidity. Women with prolonged pregnancy experience increased rates of labour induction, which itself carries risks including uterine hyperstimulation, fetal distress, and failed induction necessitating caesarean delivery.[6] The psychological burden of pregnancy extending beyond the expected due date should not be underestimated, with many women experiencing anxiety, sleep disturbances, and reduced quality of life. Additionally, chorioamnionitis, dysfunctional labour patterns, and increased operative delivery rates contribute to maternal morbidity. The cumulative effect of these complications emphasizes the need for evidence-based management strategies.

The management of post-dated pregnancy has evolved considerably over the past decades, with growing evidence supporting active management approaches. Fetal surveillance techniques including non-stress testing, biophysical profile assessment, and amniotic fluid index measurement are routinely employed to monitor fetal well-being.[7] These antenatal testing modalities aim to identify fetuses at risk of adverse outcomes, though their predictive value is not absolute. The optimal frequency and combination of surveillance tests remain subjects of ongoing research and clinical debate. Despite comprehensive monitoring protocols, some adverse outcomes in post-term pregnancies remain unpredictable, underscoring the complexity of management decisions.

Labour induction has emerged as the cornerstone of post-term pregnancy management, with multiple randomized controlled trials demonstrating its benefits in reducing perinatal morbidity and mortality.[8] Various methods of cervical ripening and labour induction are available, including mechanical methods such as transcervical balloon catheters and pharmacological agents like prostaglandins and oxytocin. The choice of induction method depends on cervical favourability, maternal factors, and institutional protocols. Evidence suggests that induction of labour at 41 weeks may reduce the risk of caesarean section compared to expectant management, challenging earlier concerns about induction increasing operative delivery rates.

The timing of intervention in post-dated pregnancy remains a critical clinical decision requiring individualization based on multiple factors. Current guidelines from major obstetric organizations recommend offering induction of labour between 41+0 and 42+0 weeks of gestation, though practices vary internationally.[9] Some studies suggest that routine induction at 41 weeks may optimize outcomes, while others advocate for expectant management with intensive fetal surveillance until 42 weeks. The decision must balance the risks of continued pregnancy against the potential complications of labour induction, considering maternal preferences, cervical status, and fetal condition. Shared decision-making between healthcare providers and pregnant women is essential in this context.

Despite extensive research, gaps in knowledge regarding post-dated pregnancy persist, necessitating continued investigation. Regional variations in management practices, outcomes, and healthcare infrastructure influence the applicability of international guidelines to local populations.[10] Studies conducted in developing countries often report higher rates of adverse outcomes compared to developed nations, reflecting differences in antenatal care quality, resources for fetal surveillance, and access to timely interventions. Understanding the specific challenges and outcomes in diverse healthcare settings is crucial for developing context-appropriate management protocols.

This study was undertaken to comprehensively evaluate the effects of post-dated pregnancy on maternal and fetal well-being at Tezpur Medical College and Hospital. By systematically analyzing maternal complications, modes of delivery, neonatal outcomes, and perinatal morbidity, we aimed to contribute to the existing body of evidence and inform clinical practice in our setting. The findings of this research will help clinicians make evidence-based decisions regarding surveillance protocols, timing of intervention, and counselling of women with post-term pregnancies. Furthermore, this study will identify specific areas requiring focused attention and resource allocation to optimize care for post-dated pregnancies in our population.

AIMS AND OBJECTIVES

The present study was conducted with the primary aim of evaluating the comprehensive effects of post-dated pregnancy on maternal and fetal well-being in the study population at Tezpur Medical College and Hospital. Post-dated pregnancy, extending beyond 42 completed weeks of gestation, remains a significant obstetric challenge requiring systematic investigation to understand its clinical implications and guide evidence-based management strategies. This research endeavoured to provide detailed insights into the spectrum of complications associated with prolonged pregnancy in the local healthcare setting.

The specific objectives formulated for this study were multifaceted and designed to capture various dimensions of maternal and fetal outcomes. The first objective was to assess the maternal complications arising from post-dated pregnancy, including the rates of labour induction, modes of delivery, operative interventions, and puerperal morbidity. Understanding the maternal impact was crucial for counselling women about potential risks and planning appropriate intrapartum management. The second objective focused on evaluating fetal outcomes, specifically examining parameters such as birth weight patterns including macrosomia, presence of meconium-stained amniotic fluid, Apgar scores at birth, and immediate neonatal complications requiring intensive care. These fetal parameters served as important indicators of intrauterine well-being and adaptation to prolonged gestation.

The third objective was to determine the incidence of perinatal morbidity and mortality in the study cohort, providing quantitative data on adverse outcomes that could inform clinical decision-making regarding timing of intervention. This included systematic documentation of neonatal intensive care unit admissions, birth asphyxia, meconium aspiration syndrome, birth trauma, and early neonatal deaths. The fourth objective aimed to analyze the relationship between advancing gestational age beyond 40 weeks and the progression of complications, thereby identifying critical time points for intervention. This temporal analysis was expected to contribute valuable information for developing gestational age-specific management protocols in post-dated pregnancies at our institution.

Finally, the study aimed to compare the observed outcomes with existing literature and identify specific areas requiring enhanced surveillance or modified management approaches in the institutional setting. By achieving these objectives, the research was expected to contribute meaningful data to the existing knowledge base on post-dated pregnancy and provide practical insights for improving clinical care and counselling of women with prolonged gestation.

Study Design and Setting

This prospective observational study was conducted in the Department of Obstetrics and Gynaecology at Tezpur Medical College and Hospital, a tertiary care teaching hospital in Assam, over a period of 13 months from June 2023 to July 2024. The study was approved by the Institutional Ethics Committee of Tezpur Medical College and Hospital and conducted in accordance with the Declaration of Helsinki principles. All participants provided written informed consent after detailed explanation of the study objectives, procedures, and potential risks. The hospital served as a referral center for high-risk pregnancies from surrounding districts, providing specialized obstetric and neonatal care services.

Sample Size and Selection

A total of 106 pregnant women with gestational age beyond 40 completed weeks were enrolled in the study. The sample size was calculated based on the anticipated complication rate of 20% with 95% confidence interval and 8% precision, accounting for potential dropouts. Consecutive sampling was employed to recruit eligible participants presenting to the antenatal clinic, labour ward, or emergency obstetric unit at Tezpur Medical College and Hospital during the study period. The study population represented a diverse socioeconomic and demographic profile typical of the hospital's catchment area.

Inclusion Criteria

Pregnant women aged 18 to 40 years with singleton pregnancies and cephalic presentation at gestational age of 40 weeks and beyond were included in the study. Accurate gestational age confirmation was mandatory, established by reliable last menstrual period corroborated with first-trimester ultrasonography (crown-rump length measurement) or second-trimester ultrasonography (biparietal diameter and femur length) when first-trimester dating was unavailable. Women with spontaneous onset of labour or scheduled for induction of labour were eligible for inclusion. Both primigravidae and multigravidae were enrolled to capture the full spectrum of post-dated pregnancy presentations.

Exclusion Criteria

Women with multiple pregnancies, malpresentations including breech and transverse lie, known fetal congenital anomalies detected on antenatal ultrasonography, and pregnancies with uncertain dates or inadequate antenatal documentation were excluded from the study. Additional exclusion criteria included pre-existing maternal medical disorders such as diabetes mellitus, chronic hypertension, thyroid dysfunction, renal disease, and cardiac conditions that could independently affect pregnancy outcomes. Pregnancy-specific complications including gestational diabetes, pregnancy-induced hypertension, preeclampsia, intrauterine growth restriction diagnosed before 40 weeks, and antepartum haemorrhage were also exclusion criteria. Women with previous uterine surgeries including caesarean section, myomectomy, or hysterotomy were excluded due to different management protocols. Patients who declined consent or were unwilling to comply with follow-up protocols were not enrolled.

Methodology and Data Collection

Detailed history was obtained from each participant including demographic data, obstetric history, menstrual history, and antenatal care details. Comprehensive physical examination was performed including vital signs assessment, general physical examination, systemic examination, and obstetric examination documenting fundal height, fetal presentation, engagement, and estimated fetal weight by Leopold's maneuvers. Routine investigations included complete blood count, blood grouping and Rh typing, random blood sugar, urine routine and microscopy, and ultrasonography for fetal biometry, amniotic fluid assessment, and placental grading.

Fetal surveillance was conducted using non-stress test (NST) performed twice weekly starting from 40 weeks of gestation. Non-reactive NST prompted further evaluation with contraction stress test or biophysical profile. Biophysical profile scoring assessed five parameters including fetal breathing movements, gross body movements, fetal tone, amniotic fluid volume, and NST reactivity. Amniotic fluid index was measured by the four-quadrant technique, with oligohydramnios defined as AFI less than 5 cm and borderline AFI between 5-8 cm. Modified biophysical profile combining NST and AFI was employed for routine surveillance. Women with abnormal surveillance parameters or those reaching 41 weeks of gestation were counselled for labour induction.

Labour Management

Labour induction was performed using standard protocols based on Bishop score assessment. Women with unfavorable cervix (Bishop score less than 6) underwent cervical ripening using intravaginal prostaglandin E2 gel or intracervical dinoprostone gel. Following cervical ripening or in women with favorable cervix, artificial rupture of membranes and oxytocin augmentation were employed as needed. Continuous electronic fetal heart rate monitoring was performed during labour in high-risk cases. Partograph was maintained to monitor labour progression. Indications for caesarean section were documented including fetal distress, failed induction, cephalopelvic disproportion, and non-reassuring fetal status. Instrumental delivery was performed when indicated using vacuum extraction or forceps following standard protocols.

Outcome Assessment

Maternal outcomes documented included mode of delivery (spontaneous vaginal delivery, instrumental delivery, or caesarean section), indication for operative intervention, duration of labour, intrapartum complications, blood loss estimation, need for blood transfusion, perineal trauma, and puerperal complications. Fetal outcomes recorded were birth weight measured immediately after delivery using calibrated electronic weighing scale, Apgar scores at 1 minute and 5 minutes assessed by the attending pediatrician, presence and grading of meconium-stained liquor, need for resuscitation, admission to neonatal intensive care unit with indication and duration, birth trauma, neonatal complications, and perinatal mortality within first seven days of life.

Follow-up Protocol

All mother-neonate pairs were followed up until hospital discharge. Postnatal maternal assessment included monitoring for postpartum complications, wound healing in operative deliveries, and counselling regarding subsequent pregnancies. Neonates were examined daily by the pediatric team, with special attention to feeding patterns, jaundice, neurological status, and any evidence of delayed complications. Neonates requiring NICU admission were followed until discharge or transfer. Data on readmissions within seven days were also collected.

Statistical Analysis

Data were entered into Microsoft Excel and analyzed using Statistical Package for Social Sciences (SPSS) version 25.0. Descriptive statistics were presented as frequencies and percentages for categorical variables, and mean with standard deviation for continuous variables. Chi-square test was applied to compare categorical variables, with p-value less than 0.05 considered statistically significant. Odds ratios with 95% confidence intervals were calculated for assessing association between risk factors and outcomes. Subgroup analysis was performed stratifying by gestational age (40-41 weeks versus beyond 41 weeks) to identify trends in complications with advancing gestation. Results were presented in tabular format for clarity and ease of interpretation.

A total of 106 pregnant women with post-dated pregnancy beyond 40 completed weeks of gestation were enrolled and analyzed in this study conducted at Tezpur Medical College and Hospital. The mean age of participants was 26.4 ± 4.2 years, with the majority (58.5%) belonging to the age group of 21-30 years. Primigravidae constituted 62.3% of the study population, while multigravidae accounted for 37.7%. The mean gestational age at delivery was 41.2 ± 0.8 weeks, ranging from 40+1 weeks to 42+4 weeks. Most women (67.9%) presented or were managed at 40-41 weeks of gestation, while 32.1% extended beyond 41 weeks.

TABLE 1: DEMOGRAPHIC AND CLINICAL CHARACTERISTICS (N=106)

The sociodemographic profile revealed that 64.2% of participants belonged to lower socioeconomic status, 28.3% to middle socioeconomic status, and only 7.5% to upper socioeconomic status. Urban residents comprised 43.4% of the cohort, while 56.6% were from rural areas. Regarding educational status, 18.9% were illiterate, 47.2% had primary to secondary education, and 33.9% had completed higher secondary or graduate education. The majority of women (81.1%) were homemakers, while 18.9% were employed.

Antenatal surveillance parameters demonstrated that non-stress test was reactive in 73.6% of cases and non-reactive in 26.4% of cases at initial assessment beyond 40 weeks. Modified biophysical profile was normal (score 8-10) in 68.9% of women, equivocal (score 6) in 22.6%, and abnormal (score less than 6) in 8.5%. Amniotic fluid index was normal (greater than 8 cm) in 61.3% of cases, borderline (5-8 cm) in 27.4%, and oligohydramnios (less than 5 cm) was present in 11.3% of women.

Labour induction was performed in 72 women (67.9%), while 34 women (32.1%) had spontaneous onset of labour. Among those requiring induction, prostaglandin E2 gel for cervical ripening was used in 53 cases (73.6% of inductions), followed by artificial rupture of membranes and oxytocin augmentation. The mean Bishop score at the time of induction was 4.8 ± 1.6. Failed induction occurred in 12 cases (16.7% of inductions), all of which required caesarean section. The mean induction-to-delivery interval was 18.6 ± 6.4 hours for successful vaginal deliveries.

TABLE 2: LABOUR AND DELIVERY OUTCOMES (N=106)

The mode of delivery distribution revealed that spontaneous vaginal delivery was achieved in 45 women (42.5%), instrumental delivery (vacuum extraction or forceps) in 10 women (9.4%), and caesarean section in 51 women (48.1%). The caesarean section rate was significantly higher compared to the institutional average for term deliveries (48.1% versus 28.3%, p<0.001). Among caesarean deliveries, emergency caesarean section constituted 86.3% and elective caesarean section 13.7%. The primary indication for caesarean section was fetal distress in 35.3% of cases, followed by failed induction in 23.5%, cephalopelvic disproportion in 17.6%, non-reassuring non-stress test in 15.7%, and other indications including cord prolapse and abruption in 7.9% of cases.

Meconium-stained amniotic fluid was observed in 45 deliveries (42.5%), representing a significant complication. Grade 1 thin meconium was present in 20 cases (44.4% of meconium cases), grade 2 moderate meconium in 15 cases (33.3%), and grade 3 thick meconium in 10 cases (22.2%). The presence of meconium was significantly associated with fetal distress (p<0.001) and lower Apgar scores at birth. Meconium aspiration syndrome was diagnosed in 8 neonates (7.5% of total births, 17.8% of meconium-stained deliveries), all of whom required neonatal intensive care unit admission and mechanical ventilation.

Birth weight analysis revealed a mean birth weight of 3285 ± 478 grams. Normal birth weight (2500-4000g) was observed in 73 neonates (68.9%), while macrosomia (birth weight exceeding 4000g) occurred in 17 neonates (16.0%). Low birth weight (less than 2500g) was present in 16 neonates (15.1%), possibly related to placental insufficiency in prolonged pregnancy. Macrosomic babies experienced higher rates of shoulder dystocia (23.5% versus 3.4%, p=0.002), birth trauma (17.6% versus 4.5%, p=0.04), and maternal perineal trauma (52.9% versus 19.1%, p<0.001) compared to normal birth weight infants.

Apgar score assessment at 1 minute showed that 73 neonates (68.9%) had scores of 7-10, 19 neonates (17.9%) had scores of 4-6, and 14 neonates (13.2%) had scores of 0-3 requiring immediate resuscitation. At 5 minutes, 78 neonates (73.6%) had Apgar scores of 7-10, 14 neonates (13.2%) had scores of 4-6, and persistent low Apgar scores (0-3) were present in 14 neonates (13.2%). These findings indicated significant birth asphyxia in a substantial proportion of neonates born in post-dated pregnancies. Neonates with 5-minute Apgar scores less than 7 had significantly higher rates of neurological complications and prolonged NICU stay.

Neonatal intensive care unit admission was required for 30 neonates (28.3%), which was significantly higher than the institutional NICU admission rate for term deliveries at Tezpur Medical College and Hospital (28.3% versus 12.6%, p<0.001). The primary indications for NICU admission were birth asphyxia requiring ventilatory support in 12 cases (40.0% of admissions), meconium aspiration syndrome in 8 cases (26.7%), sepsis evaluation in 6 cases (20.0%), hypoglycemia in 3 cases (10.0%), and birth trauma in 1 case (3.3%). The mean duration of NICU stay was 6.8 ± 3.4 days. Complete recovery with discharge in good health occurred in 25 neonates (83.3% of NICU admissions), while 3 neonates (10.0%) developed neurological sequelae, and 2 neonates (6.7%) expired despite intensive care.

TABLE 3: NEONATAL OUTCOMES (N=106)

Maternal complications were documented in 42 women (39.6%). Postpartum hemorrhage (blood loss exceeding 500 ml in vaginal delivery or 1000 ml in caesarean section) occurred in 12 women (11.3%), with 3 cases requiring blood transfusion. Perineal trauma including episiotomy extensions and lacerations was present in 25 women (23.6%), predominantly in instrumental deliveries and macrosomic babies. Wound infection developed in 6 women (5.7%) following caesarean section. Puerperal pyrexia was documented in 4 women (3.8%). No maternal mortality occurred during the study period. Operative delivery morbidity including pain, delayed mobilization, and prolonged hospital stay affected 48.1% of the study population who underwent caesarean section.

Perinatal mortality in the study cohort was 1.9% (2 cases), both occurring as early neonatal deaths within the first seven days of life. One death was attributed to severe birth asphyxia with hypoxic-ischemic encephalopathy, and the other to complications of meconium aspiration syndrome with persistent pulmonary hypertension. No stillbirths were recorded in the study period, possibly due to active surveillance and timely intervention protocols at Tezpur Medical College and Hospital. However, the perinatal mortality rate was higher compared to institutional rates for term deliveries (1.9% versus 0.8%), though the difference did not reach statistical significance (p=0.28) due to small numbers.

TABLE 4: MATERNAL COMPLICATIONS (N=106)

Subgroup analysis comparing outcomes between gestational ages of 40-41 weeks (n=72, 67.9%) and beyond 41 weeks (n=34, 32.1%) demonstrated progressive worsening of outcomes with advancing gestation. The caesarean section rate increased from 41.7% in the 40-41 weeks group to 61.8% in the beyond 41 weeks group (p=0.048). Meconium-stained liquor was present in 34.7% of deliveries at 40-41 weeks versus 58.8% beyond 41 weeks (p=0.02). Macrosomia rates were 12.5% versus 23.5% respectively (p=0.14). Low Apgar scores at 5 minutes occurred in 9.7% of the 40-41 weeks group compared to 20.6% in the beyond 41 weeks group (p=0.11). NICU admission rates were 22.2% versus 41.2% respectively (p=0.04), demonstrating statistically significant deterioration in neonatal outcomes with prolonged gestation beyond 41 weeks.

TABLE 5: COMPARISON OF OUTCOMES BY GESTATIONAL AGE

Statistical analysis revealed significant associations between various parameters. Non-reactive non-stress test was significantly associated with caesarean delivery (OR 3.8, 95% CI 1.6-9.2, p=0.002), meconium-stained liquor (OR 4.2, 95% CI 1.8-9.8, p=0.001), and low Apgar scores (OR 5.6, 95% CI 2.1-14.8, p<0.001). Oligohydramnios was significantly associated with fetal distress during labour (OR 6.4, 95% CI 2.1-19.6, p=0.001) and adverse neonatal outcomes (OR 4.8, 95% CI 1.6-14.2, p=0.005). Primigravidity was significantly associated with higher rates of labour induction (OR 2.8, 95% CI 1.2-6.4, p=0.01) and operative delivery (OR 2.4, 95% CI 1.1-5.3, p=0.03) compared to multigravidae.

The present study conducted at Tezpur Medical College and Hospital evaluated 106 cases of post-dated pregnancy to comprehensively assess their effects on maternal and fetal outcomes. The mean gestational age at delivery was 41.2 ± 0.8 weeks, which is consistent with other studies on post-term pregnancy management. The caesarean section rate of 48.1% observed in this study was significantly higher than the institutional average for term deliveries, highlighting the increased operative delivery risk associated with post-dated pregnancies. This finding aligns with the study by Shinge et al., who reported a caesarean section rate of 44.8% in post-dated pregnancies.[11]

The high rate of labour induction (67.9%) in the present study reflects the current evidence-based practice of active management in post-term pregnancies. Multiple randomized controlled trials have demonstrated that induction of labour at 41 weeks reduces perinatal morbidity and mortality without increasing caesarean section rates.[12] However, in the present study, failed induction occurred in 16.7% of cases, all requiring caesarean delivery. This is comparable to the findings of Kistka et al., who reported a 15-18% failed induction rate in post-term pregnancies, particularly in nulliparous women with unfavorable cervix.[13] The high proportion of primigravidae (62.3%) in the present cohort may explain the elevated failed induction rate, as cervical favourability is generally lower in first pregnancies.

Meconium-stained amniotic fluid was present in 42.5% of deliveries in the present study, which is significantly higher than term pregnancies. This finding corroborates the results of Treger et al., who reported meconium-stained liquor in 40-46% of post-term pregnancies.[14] The presence of meconium reflects fetal maturation and stress from uteroplacental insufficiency. In the present study, thick meconium (grade 3) was observed in 9.4% of total cases, and meconium aspiration syndrome developed in 7.5% of all neonates. This is consistent with studies showing progressive increase in meconium aspiration risk with advancing gestational age. Caughey et al. reported similar rates of meconium aspiration syndrome ranging from 5-10% in pregnancies beyond 41 weeks.[15]

The macrosomia rate of 16.0% observed in the present study is within the reported range of 10-20% for post-dated pregnancies. Eden et al. found macrosomia in 14% of pregnancies at 41 weeks, increasing to 18% at 42 weeks.[16] In the present study, macrosomic babies experienced significantly higher rates of shoulder dystocia, birth trauma, and maternal perineal trauma compared to normal birth weight infants. These complications underscore the management challenges posed by fetal overgrowth in prolonged pregnancies. However, interestingly, 15.1% of neonates in the present study had low birth weight, likely reflecting placental insufficiency in some post-term pregnancies. This dual pattern of both macrosomia and growth restriction in post-dated pregnancies has been noted in previous literature, suggesting heterogeneous pathophysiology.[17]

The incidence of low Apgar scores (less than 7 at 5 minutes) was 13.2% in the present study, significantly higher than expected for term deliveries. This finding is comparable to Olesen et al., who reported birth asphyxia in 12-15% of post-term deliveries.[18] The association between non-reactive non-stress test and low Apgar scores (OR 5.6, p<0.001) in the present study validates the importance of antenatal fetal surveillance in identifying at-risk fetuses. However, the presence of reactive NST in 73.6% of cases indicates that most post-dated pregnancies maintain adequate fetal reserve, supporting selective rather than universal intervention at 40 weeks.

The NICU admission rate of 28.3% in the present study was significantly elevated compared to term deliveries (12.6%, p<0.001). The primary indications were birth asphyxia and meconium aspiration syndrome, accounting for 66.7% of NICU admissions. These findings align with Mandruzzato et al., who reported NICU admission rates of 25-30% in post-term pregnancies, predominantly for respiratory complications.[19] The mean NICU stay of 6.8 days and the 10% rate of neurological sequelae among admitted neonates highlight the severity of complications in affected cases. While overall neonatal mortality was low (1.9%), both deaths in the present study were related to severe birth asphyxia and meconium aspiration, emphasizing these as the most critical complications of post-dated pregnancy.

Maternal morbidity was substantial, with 39.6% of women experiencing at least one complication. Postpartum hemorrhage occurred in 11.3% of cases, higher than the 7-8% reported in term deliveries. This increased hemorrhage risk may be related to uterine atony following prolonged labour or induction, as well as the higher operative delivery rate. Perineal trauma affected 23.6% of women, predominantly associated with instrumental deliveries and macrosomic infants. These findings are consistent with Dasgupta et al., who reported perineal complications in 20-25% of post-dated pregnancies with vaginal delivery.[20] The absence of maternal mortality in the present study reflects good intrapartum and postpartum care at Tezpur Medical College and Hospital, though the operative delivery morbidity affecting nearly half the cohort represents significant burden.

The subgroup analysis comparing outcomes at 40-41 weeks versus beyond 41 weeks demonstrated progressive deterioration in perinatal outcomes with advancing gestational age. The caesarean section rate increased from 41.7% to 61.8% (p=0.048), meconium-stained liquor from 34.7% to 58.8% (p=0.02), and NICU admissions from 22.2% to 41.2% (p=0.04) in the later gestational age group. These findings strongly support the recommendation for labour induction at 41 weeks rather than expectant management until 42 weeks. This is concordant with the ARRIVE trial and other recent studies showing optimal outcomes with induction at 39-41 weeks.[21]

Oligohydramnios, present in 11.3% of cases, was a strong predictor of adverse outcomes in the present study. Women with oligohydramnios had six-fold increased odds of fetal distress (OR 6.4, p=0.001) and nearly five-fold increased odds of adverse neonatal outcomes (OR 4.8, p=0.005). This association has been well-documented in literature, with amniotic fluid volume recognized as a critical marker of placental function.[22] The present findings validate the inclusion of amniotic fluid assessment in routine surveillance protocols for post-dated pregnancies.

Primigravidity emerged as a significant risk factor for complications in the present study, with higher rates of labour induction (OR 2.8) and operative delivery (OR 2.4) compared to multigravidae. This is consistent with established obstetric literature showing that nulliparous women are at greater risk for dysfunctional labour, failed induction, and caesarean delivery, particularly in post-term pregnancies with unfavorable cervix.[23] These findings suggest that primigravidae with post-dated pregnancy require heightened surveillance and lower threshold for intervention.

The strengths of the present study include its prospective design, standardized protocols for fetal surveillance and labour management, comprehensive data collection, and adequate follow-up until neonatal discharge. The study provides valuable data from a tertiary care center in Northeast India, contributing to understanding of post-dated pregnancy outcomes in resource-limited settings. However, certain limitations must be acknowledged. The sample size of 106, while adequate for primary objectives, limited the power for detecting differences in rare outcomes such as perinatal mortality. The single-center design may affect generalizability to other settings with different patient populations or resource availability. Additionally, long-term neurodevelopmental outcomes of affected neonates could not be assessed within the study timeframe.

The findings of the present study have important clinical implications for management of post-dated pregnancies at Tezpur Medical College and Hospital and similar settings. The data support implementation of active surveillance protocols starting at 40 weeks, with twice-weekly NST and weekly biophysical profile or amniotic fluid assessment. The progressive worsening of outcomes beyond 41 weeks provides strong rationale for offering induction of labour at 41+0 to 41+3 weeks rather than waiting until 42 weeks. Special attention should be given to primigravidae, women with non-reactive NST, and those with oligohydramnios, as these groups are at highest risk for adverse outcomes.

Future research directions should include larger multicenter studies to better characterize regional variations in post-dated pregnancy outcomes, cost-effectiveness analyses of different surveillance and management strategies, and long-term follow-up studies to assess neurodevelopmental outcomes in children born after post-term pregnancy. Investigation of biochemical and ultrasound markers for predicting adverse outcomes may help in risk stratification and individualized management. Additionally, qualitative research exploring women's experiences and preferences regarding management of post-dated pregnancy would inform shared decision-making approaches.

The present study conducted at Tezpur Medical College and Hospital demonstrates that post-dated pregnancy is associated with significantly increased maternal and fetal complications compared to term deliveries. The caesarean section rate of 48.1% and labour induction rate of 67.9% reflect the challenging clinical course of these pregnancies. Meconium-stained amniotic fluid affected 42.5% of deliveries, with meconium aspiration syndrome developing in 7.5% of neonates, representing a serious respiratory complication. Macrosomia occurred in 16.0% of births, contributing to increased rates of shoulder dystocia, birth trauma, and maternal perineal injuries.

Neonatal morbidity was substantial, with 28.3% requiring NICU admission, predominantly for birth asphyxia and meconium aspiration syndrome. Low Apgar scores at 5 minutes were documented in 13.2% of newborns, indicating significant compromise at birth. Maternal complications affected 39.6% of women, including postpartum hemorrhage (11.3%), perineal trauma (23.6%), and operative delivery morbidity. The subgroup analysis revealed progressive worsening of outcomes with advancing gestational age beyond 41 weeks, with statistically significant increases in caesarean section rates, meconium-stained liquor, and NICU admissions.

The findings strongly support active management protocols for post-dated pregnancies, including comprehensive fetal surveillance starting at 40 weeks with non-stress testing and biophysical profile assessment. Labour induction should be offered between 41+0 and 41+3 weeks of gestation rather than expectant management until 42 weeks, given the demonstrated deterioration in outcomes beyond 41 weeks. Special attention should be directed toward high-risk groups including primigravidae, women with non-reactive NST, oligohydramnios, or suspected macrosomia, as these factors significantly increase the risk of adverse outcomes.

Continuous intrapartum monitoring is essential for early detection of fetal distress and meconium passage. Ready availability of neonatal resuscitation expertise and NICU facilities is crucial for managing the increased neonatal morbidity associated with post-dated pregnancies. Counselling of women about the risks of post-term pregnancy and the benefits of timely intervention should be an integral component of antenatal care. Implementation of standardized protocols for surveillance and management of post-dated pregnancies at Tezpur Medical College and Hospital, based on the evidence from this study and existing literature, will contribute to improved perinatal outcomes.

Further research with larger sample sizes and long-term follow-up is needed to better characterize optimal timing of intervention, cost-effectiveness of different management strategies, and neurodevelopmental outcomes of children born after post-term pregnancy. Continued surveillance and audit of outcomes in post-dated pregnancies will help refine management protocols and ensure delivery of evidence-based care to this high-risk obstetric population

1. Galal M, Symonds I, Murray H, Petraglia F, Smith R. Postterm pregnancy. Facts Views Vis Obgyn. 2012;4(3):175-87. PMID: 24753906; PMCID: PMC3987368.
2. Olesen AW, Westergaard JG, Olsen J. Perinatal and maternal complications related to postterm delivery: a national register-based study, 1978-1993. Am J Obstet Gynecol. 2003;189(1):222-7. doi: 10.1067/mob.2003.446. PMID: 12861169.
3. Shinge N, Yadav Y, Pawar Y. Maternal and fetal outcome in postdated pregnancy. Int J Reprod Contracept Obstet Gynecol. 2019;8(6):2295-9. doi: 10.18203/2320-1770.ijrcog20192265.
4. Divon MY, Haglund B, Nisell H, Otterblad PO, Westgren M. Fetal and neonatal mortality in the postterm pregnancy: the impact of gestational age and fetal growth restriction. Am J Obstet Gynecol. 1998;178(4):726-31. doi: 10.1016/s0002-9378(98)70482-x. PMID: 9579434.
5. Dasgupta S, Nath P. Maternal and perinatal outcome in prolonged pregnancy. J Obstet Gynaecol India. 2020;70(1):42-6. doi: 10.1007/s13224-019-01276-0. PMID: 32189848; PMCID: PMC7031400.
6. Mozurkewich EL, Chilimigras JL, Berman DR, Perni UC, Romero VC, King VJ, et al. Methods of induction of labour: a systematic review. BMC Pregnancy Childbirth. 2011;11:84. doi: 10.1186/1471-2393-11-84. PMID: 22032440; PMCID: PMC3224350.
7. Bochner CJ, Williams J 3rd, Castro L, Medearis A, Hobel CJ, Wade M. The efficacy of starting postterm antenatal testing at 41 weeks as compared with 42 weeks of gestational age. Am J Obstet Gynecol. 1988;159(3):550-4. doi: 10.1016/s0002-9378(88)80005-2. PMID: 3048095.
8. Gülmezoglu AM, Crowther CA, Middleton P, Heatley E. Induction of labour for improving birth outcomes for women at or beyond term. Cochrane Database Syst Rev. 2012;(6):CD004945. doi: 10.1002/14651858.CD004945.pub3. PMID: 22696345.
9. Middleton P, Shepherd E, Crowther CA. Induction of labour for improving birth outcomes for women at or beyond term. Cochrane Database Syst Rev. 2018;5(5):CD004945. doi: 10.1002/14651858.CD004945.pub4. PMID: 29741208; PMCID: PMC6494436.
10. Caughey AB, Sundaram V, Kaimal AJ, Cheng YW, Gienger A, Little SE, et al. Maternal and neonatal outcomes of elective induction of labor. Evid Rep Technol Assess (Full Rep). 2009;(176):1-257. PMID: 19408968; PMCID: PMC4781486.
11. Shinge N, Yadav Y, Pawar Y. Maternal and fetal outcome in postdated pregnancy. Int J Reprod Contracept Obstet Gynecol. 2019;8(6):2295-9. doi: 10.18203/2320-1770.ijrcog20192265.
12. Middleton P, Shepherd E, Crowther CA. Induction of labour for improving birth outcomes for women at or beyond term. Cochrane Database Syst Rev. 2018;5(5):CD004945. doi: 10.1002/14651858.CD004945.pub4. PMID: 29741208.
13. Kistka ZA, Palomar L, Lee KA, Boslaugh SE, Wangler MF, Cole FS, et al. Racial disparity in the frequency of recurrence of preterm birth. Am J Obstet Gynecol. 2007;196(2):131.e1-6. doi: 10.1016/j.ajog.2006.06.093.
14. Treger M, Hallak M, Silberstein T, Friger M, Katz M, Mazor M. Post-term pregnancy: should induction of labor be considered before 42 weeks? J Matern Fetal Neonatal Med. 2002;11(1):50-3. doi: 10.1080/jmf.11.1.50.53.
15. Caughey AB, Washington AE, Laros RK Jr. Neonatal complications of term pregnancy: rates by gestational age increase in a continuous, not threshold, fashion. Am J Obstet Gynecol. 2005;192(1):185-90. doi: 10.1016/j.ajog.2004.06.024.
16. Eden RD, Seifert LS, Winegar A, Spellacy WN. Perinatal characteristics of uncomplicated postdate pregnancies. Obstet Gynecol. 1987;69(3 Pt 1):296-9. PMID: 3808498.
17. Clausson B, Cnattingius S, Axelsson O. Outcomes of post-term births: the role of fetal growth restriction and malformations. Obstet Gynecol. 1999;94(5 Pt 1):758-62. doi: 10.1016/s0029-7844(99)00436-2.
18. Olesen AW, Westergaard JG, Olsen J. Perinatal and maternal complications related to postterm delivery: a national register-based study, 1978-1993. Am J Obstet Gynecol. 2003;189(1):222-7. doi: 10.1067/mob.2003.446.
19. Mandruzzato G, Alfirevic Z, Chervenak F, Gruenebaum A, Heimstad R, Heinonen S, et al. Guidelines for the management of postterm pregnancy. J Perinat Med. 2010;38(2):111-9. doi: 10.1515/jpm.2010.057.
20. Dasgupta S, Nath P. Maternal and perinatal outcome in prolonged pregnancy. J Obstet Gynaecol India. 2020;70(1):42-6. doi: 10.1007/s13224-019-01276-0.
21. Grobman WA, Rice MM, Reddy UM, Tita ATN, Silver RM, Mallett G, et al. Labor Induction versus Expectant Management in Low-Risk Nulliparous Women. N Engl J Med. 2018;379(6):513-23. doi: 10.1056/NEJMoa1800566.
22. Morris JM, Thompson K, Smithey J, Gaffney G, Cooke I, Chamberlain P, et al. The usefulness of ultrasound assessment of amniotic fluid in predicting adverse outcome in prolonged pregnancy: a prospective blinded observational study. BJOG. 2003;110(11):989-94. PMID: 14592582.
23. Heimstad R, Romundstad PR, Eik-Nes SH, Salvesen KA. Outcomes of pregnancy beyond 37 weeks of gestation. Obstet Gynecol. 2006;108(3 Pt 1):500-8. doi: 10.1097/01.AOG.0000227783.65800.0f.