A comparative study of the maternal, fetal and early neonatal outcome at term and post-term gestation

Objectives: To study the maternal and fetal outcome and complications in post-term pregnancies and to compare them with an equal number of term pregnancies. Materials and Methods: The study was conducted in the department of OBG, AIMS, B.G. Nagara. 50 cases of post-term singleton pregnancies with Gestational age > 42 weeks, 18-35 years of age with reliable dates and no obstetric or medical complications were the study group. The control group comprised of 50 singleton pregnancies between 37 and 42 weeks, 18-35 years of age with reliable dates and no obstetric or medical complications. The maternal morbidity was based on mode of delivery, operative interventions, injuries, PPH and Fetal morbidity was based on number of fetuses with meconium staining of amniotic fluid, NICU admissions, asphyxia, metabolic complications. Results: Post-term pregnancy was found to be associated with increased morbidity, In the mother, labor had to be induced in a significant number of cases (p 0.070) since a large number of them had a low Bishop's score (p=0.086). Operative interference in the form of LSCS was positively associated with post-term (p=0.166) with causes varying from the failure of induction, prolonged labor. fetal distress, macrosomia and oligohydramnios (p <004). Perinatal morbidity was significantly associated with Post-term (32.0% vs 6.06) with P<0.001 due to birth asphyxia, meconium aspiration syndrome, the incidence of Meconium stained liquor being 60% (P-0.001). Conclusion: The maternal and fetal morbidity is significantly increased after 42 weeks. There is a great need for accurate dating of pregnancy. The importance of induction of labor at 41 weeks and definitely not beyond 42 weeks cannot be sufficiently stressed.


Introduction
Post Term Pregnancy-Incidence of post-term pregnancy varies according to the definitions used and the population studied. A literature review covering periods from the early 1920s including national, regional and hospital data from many countries revealed that incidence rates for postterm pregnancy varied from 4.4% [1]; 3-12% [2]; 3% [3].
Only 4% -7.3% of pregnancies extend beyond 43 weeks [5]. 20% to 40% of post-term pregnancies result in post maturity syndrome [6]. Clifford in 1965 categorized postmaturity syndrome, into three clinical stages. The signs of post maturity cannot be considered pathognomonic because they are absent in one-fifth to one-third of postterm neonates and may not infrequently be observed in infants born at term.
Manuscript received: 14 th January 2020 Reviewed: 24 th January 2020 Author Corrected: 30 th January 2020 Accepted for Publication: 5 th February 2020 Rayburn et al (1982)" observed grade II or III placentas in their term population but found cases of post-maturity with grade III placenta [2]. The post-term placenta has a high mean placental weight and a greater amount of calcium deposition and greater incidence of grade III placenta.
According to Michael Y. Divon et al, oligohydramnios (defined as an amniotic fluid index < cms) is associated with potential perinatal complications or compromise [3]. It develops in about 0.5% to 4% of these pregnancies depending on the population, the interval between testing and delivery and criteria for diminished amniotic fluid volume Prominent increases or decreases in amniotic fluid index of post-term patients had no associated adverse fetal outcome irrespective of the rate of change of the amniotic fluid index provided the final value remained > 5.0 cms. Post-term pregnancy is frequently encountered and often has a poor outcome. The early literature suggested an

Original Research Article
Obsgyne Review: Journal of Obstetrics and Gynecology Available online at: www.medresearch.in 2 |P a g e increase in perinatal mortality in post-term pregnancy, while more recent reports imply that the risk of perinatal death resides only in the small, growth-retarded fetus. Thus, said Robert D. Eden et al after analyzing 3457 postterm infants to a control group of 8135 infants born at 40 weeks [10].
There is a seven times increase in neonatal mortality and morbidity in post-term infants weighing below 2,500 g at birth [5] than with birth weight above 2500 gms. Significance is assessed at a 5% level of significance. Analysis Chi-square/ Fisher Exact test has been used to find the significance of the study parameter on the categorical scale between two or more groups. 95% Confidence Interval has been computed to find the significant features. Confidence Interval with a lower limit of more than 50% is associated with statistical significance.

Aims of the Study
Statistical software: The Statistical software namely SPSS 15.0, Stata 8.0, MedCalc90.1 and Systat 11.0 were used for the analysis of the data and Microsoft Word and Excel have been used to generate Tables, etc.  Table 1 represents the parity wise distribution of post-term cases in this study. The post-term pregnancy rate was 66% in primis and 34% in multi. This shows an increased incidence of post-term gestation in primigravidas compared to multigravida.

Original Research Article
Obsgyne Review: Journal of Obstetrics and Gynecology Available online at: www.medresearch.in 3 |P a g e

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-- Table 2 highlights the age-wise distribution of post-term cases with their corresponding percentages. Unripe cervix with a score <6 was found in 40% of post-term cases Inference Failed induction is statistically associated with term or post-term with P=0.644 Table 5 represents the number of cases of post-term and term that were induced. In the post-term, 10 cases were induced with prostaglandins and one with oxytocin, 7 cases had failed induction of fetal distress and underwent emergency LSCS. In term gestations 6 cases were induced with prostaglandins, 3 underwent LSCS, 2 instrumental deliveries, and I had a normal vaginal delivery  Table 6 represented various modes of delivery.

Original Research Article
Obsgyne Review: Journal of Obstetrics and Gynecology Available online at: www.medresearch.in 4 |P a g e Post-term gestation outcome shows an increased incidence of female children. The birth weight of post-term babies is higher than term babies. There were 5 cases of macrosomia (Bt weight >4 kgs), the heaviest baby in the study was 4.4 kgs. The incidence of meconium both thick and thin meconium-stained liquor is more in post-term gestational, presence of thick meconium-stained liquor was 16% in the present study and thin meconium was 14%, leading to a total of 30% Perinatal morbidity is more in post-term gestation. The meconium aspiration syndrome in the present study was 12 % and birth asphyxia was 18%.

Original Research Article
Obsgyne Review: Journal of Obstetrics and Gynecology Available online at: www.medresearch.in 5 |P a g e  There were no antenatal deaths due to post-term pregnancy in the present study 2 cases had cervical tears which were sutured one had a third-degree perineal tear, 1 had an episiotomy extension 2 cases had atonic PPH, 1 had traumatic PPH. 1 case presented with chorioamnionitis. In teen pregnancies 2 cases had mild atonic PPH, 1 had an episiotomy extension and one had a cervical tear The number of cases of oligohydramnios is very much more in post-term gestation

Discussion
In the present study, the post-term pregnancy rate was 66% in primi and 34% in multi. This shows an increased incidence of post-term gestation in primigravidas compared to multigravida. A similar observation was made by Vorherr [11]. Table 2 shows the age-wise distribution of post-term cases with their corresponding percentages. The youngest mother in the study was 18 years old. The eldest mother was 29 years old. There were no cases over 30 years.
In the present study, there is an inverse relationship between maternal age and the incidence of post-term pregnancy. 10% of post-term was less than 20 years of age. 82% were between the age group of 20-25. A similar observation was made by Eden et al" [10] where the mean age of post-term was 25.8 years. A similar observation was also made by Vorherr (37.5%) [11]. Table 3 shows that induced labor is significantly associated with Post-term with x2=3.151; p=0.070+.
The bishops score is less than or equal to 6 in more number of cases of post-term than term. Unripe cervix with a score <6 was found in 40% of post-term cases. A study by Helmuth Vorherrs (1975) showed that 70% of post-term pregnancies presented with unripe cervix [11]. Table 5 shows the number of cases of post-term and term that were induced. In the post-term, 10 cases were induced with prostaglandins and one with oxytocin, 7 cases had failed induction of fetal distress and underwent emergency LSCS. In term gestations 6 cases were induced with prostaglandins, 3 underwent LSCS, 2 instrumental deliveries, and 1 had a normal vaginal delivery Uterine inertia occurred twice as frequently in post-term than term gestation (Vorherr et.al) with a high cesarean rate due to increased failure of induction [11].
Cesarean delivery is more in the post-term group. The rate of instrumental delivery is also increased. The rate of surgical intervention increased in cases of post-term labor, because of increased frequency of prolonged labor, fetal hypoxia, and failed induction. In the present study, the rate of cesarean section delivery was 42% when compared to 26% in controls.
Cesarean section births are approximately doubled in the post-term as compared with term deliveries [1]. In an Indian study, the Caesarean section rate was 30% in the induced group when compared to 8 in the spontaneous group [9].
In the present study, the rate of cesarean delivery is high probably due to patients being referred to the referral hospital after a trial of labor was given.
Instrumental Delivery: The present study shows 18% of instrumental deliveries compared to 16% in the control group. Eden et al, in a study, showed 17% of instrumental deliveries [10], whereas Alexander et al.," had 9% of instrumental deliveries at 42 weeks and 8% at 41 weeks [12].
The birth weight of post-term babies is higher than term babies shown in Table 8. There were 5 cases of macrosomia (Bt wt >4 kgs), the heaviest baby in the study was 4.4 kgs. Fetal macrosomia occurs more frequently in post-term than in term pregnancy [10].
The incidence of meconium both thick and thin meconium-stained liquor is more in post-term gestational, presence of thick meconium-stained liquor was 16% in the present study and thin meconium was 14%, leading to a total of 30%. Post-term infants have meconium aspiration eight times as often, require ventilation, have air leaks and pulmonary hypertension more commonly than term neonates [1].
Perinatal morbidity is more in post-term gestation as depicted in Table 10. The meconium aspiration syndrome in the present study was 12 % and birth asphyxia was 18%. A similar observation was seen in a study by the National Institute of Child Health and Human Development Network of Maternal -Foetal Medicine" where the rate of meconium aspiration syndrome was 13-46% [8].
In the current study, as shown in There were no antenatal deaths due to post-term pregnancy in the present study 2 cases had cervical tears which were sutured one had a third-degree perineal tear, 1 had an episiotomy extension 2 cases had atonic PPH, 1 had

Original Research Article
Obsgyne Review: Journal of Obstetrics and Gynecology Available online at: www.medresearch.in 7 |P a g e traumatic PPH. 1 case presented with chorioamnionitis. In teen pregnancies 2 cases had mild atonic PPH, 1 had an episiotomy extension and one had a cervical tear, these findings elicited by Table 12.
The main cause of morbidity in the post-term consisted of an increased rate of cesarean section, perineal tears, cervical tears, and postpartum hemorrhage. The rate of morbidity due to cervical and perineal tears is 8% in the post-term group when compared to term. In a study by Rand et al. (2000) 33 at post-term and 2.6% at term had tears during delivery [20].
The current study had more cases of oligohydramnios than the above study (Table 13). The number of cases of cord around the neck was increased in post-term cases probably indicating reduced liquor. One baby was extracted with 4 loops of cord around the neck.
According to Michael Y. Divon et al. oligohydramnios (defined as an amniotic fluid index <5 cms) is associated with potential perinatal complications or compromise [3].
It develops in about 0.5% to 4% of these pregnancies depending on the population, the interval between testing and delivery.
The mean placental weight is more in post-term babies.
The placental pathology and aging in the form of calcification and infarction are noted The post-term placenta has a high mean placental weight and a greater amount of calcium deposition and greater incidence of grade III placenta [11].
Limitations of the study: Sample size was 60, the need for larger trials is necessary for better understanding of the management of prolonged pregnancy,

Conclusion
Prolonged pregnancy continues to evoke anxiety in both patient and obstetrician. There is no single line of management in post-term pregnancy. Detailed information regarding L.M.P, previous menstrual cycles, O.C.P use has to be obtained.
An ultrasound scan in the first trimester or at the first antenatal visit is a must, as E.D.D by first-trimester ultrasound has been proved to be more accurate than menstrual dating.
The management of post-term pregnancy viz. expectant vs active management depends on the literacy and socioeconomic condition of the mother. Due to financial constraints, repeated investigations and antepartum fetal surveillance are difficult. The policy of induction of labor at 41 weeks seems to be feasible, definitely not later than 42 weeks as an association of post-term pregnancy with fetal distress, meconium staining, and other comorbidities are increased. The key to a favorable outcome in post-term pregnancy requires a blending of timely consultation with a specialist in maternal-fetal medicine. an individualized an of management for cash patient and patient involvement in treatment decisions. With a merging of these concepts, the likelihood of an adverse perinatal outcome in prolonged pregnancy can be minimized.

What does the study add to the existing knowledge?
There is always an anxiety of both patient and obstetricians for the continuation of pregnancy beyond 40 weeks. From this study, it can be concluded that induction can be done at 41 weeks of gestation in low-risk pregnancies, but feto-maternal surveillance is essential.