Dr.  Francis E. Alu

Department of Obstetrics and Gynaecology, 

Maitama District Hospital/Nile University of Nigeria Abuja

+2348037206243

francis.alu@nileuniversity.edu.ng

INTRODUCTION

Labour induction is the initiation of uterine contractions prior to its spontaneous onset, after the age of viability, by mechanical or pharmacological stimulation of the uterus in order to achieve vaginal delivery.¹ It is an important intervention in obstetric practice and is usually not without risks. The decision to induce labour is most often made where pregnancy continuation is not beneficial and may be harmful to either the foetus or the mother, or both.^1,2 Induction of labour when successful obviates the need for caesarean section with its attendant complications.

Indications for induction of labour may be for obstetric or medical reasons and includes postdate pregnancy, hypertensive disorders of pregnancy including pre-eclampsia and eclampsia, diabetes mellitus, renal disease, chronic pulmonary disease, rhesus isoimmunisation, premature rupture of membranes (PROM), intrauterine fetal death (IUFD), and a host of other medical conditions^1-5 as well as such indications as maternal requests for social reasons, and Obstetricians’ preferences.^6,7

The rates of induction of labour vary from one region to another and even within countries, with higher rates reported in developed Countries compared with developing Countries. The World Health Organization (WHO) estimates that 25% of women in developed countries have their labour induced.⁵ An incidence of 22.5% has been reported in the United States⁷ and 3-16% in the sub-Saharan Africa.^10,11,12 

The WHO recommends that induction of labour should be performed only when there is a clear medical indication, and the expected benefits outweigh potential risks. Induction of labour when performed for the right indication with adequate monitoring has been shown to reduce perinatal morbidity and mortality drastically, especially after the due date.⁵ Induced labour is associated with longer and more painful labour compared with spontaneous labour. Other reported risks of induced labour include failed induction, uterine rupture, increased rates of Caesarean section and instrumental vaginal delivery, primary postpartum haemorrhage (PPH), uterine hyperstimulation with foetal distress, cord prolapse, hyperbilirubinaemia, hyponatraemia, inadvertent preterm delivery with increased perinatal mortality rate, and sometimes maternal mortality.^1-5 However, it has been suggested that some of the observed complications of induced labour and increased risks of Caesarean section maybe due to the initial pathological condition that necessitated the induction of labour rather than the induction process itself.^8,9

Cervical ripening is an important component of IOL and the Bishop scoring system is often used to determine the ‘favourability’ of the cervix for induction. Methods of induction include use of prostaglandins and their analogues (PGE2 and misoprostol), oxytocin, balloon foley catheter, amniotomy, and membrane sweeping or stripping. These methods are often used alone or in combinations depending on adopted protocols. Oxytocin titration is usually started either prior to or following amniotomy and often preceded by foley catheter or misoprostol ripening of the “unripe” cervix.

This study aims to retrospectively review the patterns and obstetric outcomes of women who had induction of labour at the maternity unit of Maitama District Hospital Abuja, Northcentral Nigeria, over a five-year period (2018-2022). The findings from the study, which is the first of its kind in any of the FCTA Abuja district hospitals, will not only contribute to existing body of knowledge on the subject but also help in making evidence-based recommendations for the judicious conduct of induction of labour.

MATERIALS AND METHODS

This was a retrospective study of the patterns and outcome of induced labours conducted at the maternity unit of Maitama District Hospital (MDH) Abuja, Northcentral Nigeria, between January 1^st 2018 and December 31^st 2022. MDH is one of the public secondary healthcare facilities owned by the Federal Capital Territory Administration (FCTA) Abuja and is located in the Abuja Municipal Area Council (AMAC) of the territory. It provides specialized obstetric care for pregnant women with uncomplicated and complicated pregnancies and serves as a referral centre for patients from both public and private health institutions in the Federal Capital Territory (FCT) Abuja and the neighbouring States of Nasarawa, Niger, Benue, Kaduna, and Kogi. The Hospital runs an electronic medical records system (E-MRS) with a well secured data entry and confidentiality which facilitates data retrieval when required. 

Data were collected from the patients’ records on the E-Medical Records database and also from the labour ward and theatre records when necessary. 

The relevant socio‑demographic and obstetric characteristics of the patients obtained included: age, occupation, educational level, parity, gestational age at induction/delivery, booking status, indication for IOL, method of IOL, delivery outcome, as well as maternal and foetal outcomes/complications. The information obtained was transferred into an Excel spreadsheet for analysis using Statistical Package for Social Sciences (SPSS) version 26.0 (SPSS 26.0, IBM Chicago) with results presented in tables and simple percentages. Frequency distribution was generated for all categorical variables for the descriptive aspect of the analysis. Means, standard deviations and other descriptive measures were determined for quantitative variables. Chi square test was applied for the comparison of proportions and evaluating association of categorical variables where applicable. A confidence interval of 95% and a p-value of < 0.05 was adopted as the level of statistical significance. Ethical approval was sought from the Institution’s Ethics Committee. 

The main outcome measures were the proportion of successful IOL and failed IOL, while the secondary outcome measures were maternal and foetal outcomes and complications associated with IOL. Failed IOL was defined as failure to achieve spontaneous vaginal delivery without any operative intervention such as instrumental vaginal delivery (Forceps or Vacuum) or emergency Caesarean section.

RESULTS

During the period of study, there were a total of 4,534 deliveries and 131 induced labours giving an induction of 

labour rate of 2.9%. The majority of the patients was within the 26-30 age group with mean of 29.91±4.251 years. 

Most of the women attained tertiary level of education (74.1%), were booked (91.6%) and were civil servants (47.3%).  Nulliparity (Para 0) accounted for 68.7% of cases while only three (2.3%) were grandmultipara (Para 5 and above). The mean parity was 0.61±1.247. The mean gestational age at induction was 40.39±1.444 weeks with majority (83.2%) in the 40-42 weeks group (Table 1). 

Table 1 shows the sociodemographic characteristics of parturients who had induction of labour within the study period.

Table 2 shows the indications, methods and outcome of labour induction. The commonest indication for IOL was postdate pregnancy accounting for 79.4% of cases followed by hypertensive disorders of pregnancy (chronic hypertension, severe pre-eclampsia/eclampsia) which accounted for 6.9%. Pre-labour premature rupture of membranes (PROM) and intrauterine foetal death (IUFD) accounted for 5.3% each while Rhesus isoimmunization was an indication in 3.1% of cases.

Majority of the patients (86.3%) had intracervical foley catheter ripening of the cervix with amniotomy and oxytocin titration while use of misoprostol alone accounted for only 1.5%. Misoprostol was employed for all the cases of intrauterine foetal death (IUFD) either alone or 

 Table 1: Sociodemographic characteristics of parturients who had induction of labour.

 Table 2: Indication, Method of Induction of labour and Mode of delivery

 in combination with oxytocin. Oxytocin titration was used alone in all cases with favourable Bishop score (≥6).

Vaginal delivery (successful induction) was achieved in 40.5% of the parturients while 58.8% had failed IOL resulting in emergency CS for various reasons such as cephalopelvic disproportion, foetal distress, and poor progress in labour due to cervical dystocia. Cephalopelvic disproportion was the commonest reason for CS accounting for 74.0% of all the CS followed by foetal distress (19.5%) and poor labour progress (5.2%). There was one case of antepartum haemorrhage constituting 1.3%. Vacuum extraction was performed for one case of foetal distress at full cervical dilatation (Table 2). All cases of induction due to IUFD resulted in successful vaginal delivery.

one case of antepartum haemorrhage constituting 1.3%. Vacuum extraction was performed for one case of foetal distress at full cervical dilatation (Table 2). All cases of induction due to IUFD resulted in successful vaginal delivery.

Table 3: Outcome of IOL according to parity

 Table 3 shows the outcome of IOL according to parity. Successful vaginal delivery was highest among the multiparous group (Para 1-4) accounting for 78.9%. Failed IOL resulting in emergency CS was commonest among the nulliparous group (Para 0) with only 23.3% having successful vaginal delivery.

Table 4 shows the foetal outcome and maternal complications following induction of labour. The mean birthweight of the babies was 3.31±0.471kg with more than 90% weighing between 2.5kg and 4.0 kg and only eight (6.1%) weighing > 4kg. The birthweights of 3 of the IUFD prior to induction were not recorded. 

Most of the neonates (79.4%) had good Apgar scores at 1 and 5 minutes (Apgar scores ≥7) with eight neonates (6.1%) having moderate to severe birth asphyxia and all required neonatal intensive care unit (NICU) admission. There were three neonatal deaths (one intrapartum fresh stillbirth following PROM at 35 weeks, one immediate neonatal death from meconium spiration syndrome (MAS) in a postdate pregnancy (41 weeks+5days), and one death in the NICU two days postpartum in a parturient with severe pre-eclampsia at 36 weeks +2days gestational age). There were eight cases of intrauterine foetal death (IUFD) prior to induction.   

Maternal complications noted included three cases of primary postpartum haemorrhage (PPH) which accounted for 42.9% of all maternal complications followed by genital tract laceration, and uterine hyperstimulation. Two parturients required intensive care unit (ICU) admission on account of PPH with shock, that required multiple blood transfusion, and maternal severe hypertension. There was no maternal death from induction of labour during the period of study

Table 4: Foetal Outcome and Maternal Complications of Induced Labour

. 

DISCUSSION 

This study shows an induction rate of 2.9% which is comparable with rates reported in other studies.^{10,11,13,14,16} It is, however, much lower than rates reported in some other studies in Nigeria and other African countries.^12,15,18,26 The observed differences may be attributed to the various indications and methods of induction employed, the length of the study period and the population studied, and the non-homogenous nature of the sample sizes among other factors. The low induction rate recorded in our study tends to corroborate the fact that induction of labour is generally low in health facilities in Africa and other low-income countries.^2,10,11

Postdate pregnancy was the main indication for IOL in this study accounting for 79.4%. This is consistent with the findings reported in other studies in Nigeria and other African countries.^{13,14,16,22,27} However, postdate pregnancy may be affected by inaccurate determination of gestational age due to unsure of dates of last menstrual period by patients and the lack of early ultrasound scan dating of pregnancy.  Other studies in Nigeria and parts of Africa however reported premature rupture of membranes and hypertensive diseases as the commonest indications^11,20,25,26

The commonest method of induction from our study is the combination of foley catheter ripening of the cervix, amniotomy and oxytocin titration. The use of misoprostol for IOL in pregnant women with live foetuses at term is restricted in all Federal Capital Territory Administration (FCTA) Abuja owned Health facilities including the hospital of study as a matter of policy. This policy arose as a result of previous recorded incidences of maternal and foetal complications (uterine rupture and perinatal mortality) resulting from its use in some of the facilities, coupled with the non-registration of misoprostol for induction of labour by the National Agency for Food and Drug Administration and Control (NAFDAC) in Nigeria. In contrast, other studies in Nigeria and other African countries reported use of misoprostol as the commonest method of induction.^16,17,26,27 The efficacy and safety of misoprostol use in induction of labour in pregnancies with live foetus has been documented in studies in Nigeria and other countries.^27,28 The high cost and non-availability of PGE2, the lower efficacy of other methods of labour induction, the risks associated with misoprostol use in pregnancies with live foetuses, and the lack of facilities for intensive intrapartum monitoring make the use of foley catheter and oxytocin combination a more viable option in low-resource settings.²  Misoprostol in low doses is only used for induction of labour for IUFD cases in the hospital of study. 

The successful induction rate of 40.5% recorded in this study is low compared with some studies while Caesarean section (CS) due to failed induction which accounted for 58.8% is high compared with those reported in other studies.^{13,16,17,21,27} The observed differences may be related to the different indications and methods of induction used in those studies where misoprostol was the main induction agent. The high vaginal delivery rate recorded in our study in those with IUFD may be due to the use of misoprostol and the longer window period allowed for induction due to the elimination of concerns about foetal distress.

The main reason for failed induction in this study is cephalopelvic disproportion (74.0%), similar to the findings in some studies¹⁸ but in contrast with those reported by Ugwuoroko et al¹⁶ and Lawani et al¹⁷ where foetal distress was the main reason.

Majority of the women were nulliparous (Para 0) and this is consistent with findings in other studies. Successful vaginal delivery rate was, however, highest among the multiparous women with lower rates recorded among the nullipara as previously observed in other studies.^13,23,27This is attributed to the more favourable Bishop scores often registered in this group of parturients prior to induction of labour.

Favourable neonatal outcome as evidenced by good Apgar scores at 1 and 5 minutes was recorded in 79.4%, a finding that is comparable with those of other studies.^13,16,19 There were, however, eight cases of moderate to severe birth asphyxia with three neonatal deaths all related to maternal conditions prior to induction. This finding tends to support the observation that perinatal mortality following IOL may be related to the initial pathological condition that necessitated the induction rather than the induction process itself.^8,9

The main maternal complication recorded in this study is primary postpartum haemorrhage (PPH) representing 42.9% of all maternal complications, a finding similar to other studies.^16,18,21 Out of the three cases of PPH, one required multiple blood transfusions and intensive care unit (ICU) management. Cases of failed induction are considered as adverse maternal outcome since they ended up in operative interventions with their attendant risks to the mother. There was no cases of uterine rupture and no maternal death.

The main limitation of the study is the fact that specific indications for induction which may on their own affect obstetric outcomes were not excluded in the review. The non-availability and use of infusion pumps for accurate delivery of oxytocin in the facility of study and the restriction on the use of misoprostol for induction may also have affected the obstetric outcomes observed, including the high failed induction rate.

CONCLUSION 

The study showed that higher parity is associated with higher rate of successful induction. However, the risk of uterine rupture is increased in this category of parturients. Hence, we recommend careful selection of patients, and adequate intrapartum monitoring for all cases of induced labours, taking into consideration available human and material resources.

REFERENCES

1. Royal College of Obstetricians and Gynaecologists (RCOG). Induction of labour: Evidence-based clinical guidelines, Number 9; London, RCOG Press 2001.
2. World Health Organization. WHO recommendations for induction of labour. 2011. Geneva. https://apps.who.int/iris handle/10665/44531
3. Sanchez-Ramos L. Induction of labour. Obstet Gynaecol Clin North Am 2005; 32:181-200. 
4. McEwan A. Labour. In: Baker PN, Kenny LC, editors. Obstetrics by Ten Teachers. 19^th ed. London: Hodder Arnold, An Hachette UK Company; 2011. p. 185-223.
5. World Health Organization. WHO recommendations: Induction of labour at or beyond term. 2018. Geneva. https://apps.who.int/iris/handle/10665/277233
6. Simpson KR, Thorman KE. Obstetric conveniences: Elective induction of labour, Caesarean birth on demand and other potentially unnecessary interventions. J Perinat Neonatal Nurs 2005; 19(2): 134-144. 
7. Rayburn WF, Zhang J. Rising rates of labour induction: present concerns and future strategies. Obstet Gynecol 2002; 100 (1): 164-167
8. Caughey AB, Sundaram V, Kaimal AJ, Gienger AL, Cheng YW, McDonald KM, et al. Systematic Review: Elective induction of labor versus expectant management of pregnancy. Ann Intern Med 2009 Aug; 151(4): 252-263. 
9. Gulmezoglu AM, Crowther A, Middleton P. Induction of labour for improving both outcomes for women at or near term. Cochrane Database Syst Rev 2006; 4: CD004945
10. Vogel JP, Souza JP, Gulmezoglu AM. Patterns and outcomes of induction of labour in Africa and Asia: a secondary analysis of the WHO Global Survey on Maternal and Neonatal Health. PLoS One 2013; 8(6): 65612
11. Fawole B, Nafiou I, Machoki M, Wolomby-Molondo J-J, Mugerwa K, Neves I et al. Unmet need for induction of labour in Africa: secondary analysis from the 2004-2005 WHO Global Maternal and Perinatal Health Survey (A cross-sectional survey). BMC Public Health 2012; 12: 722.
12. Ade-Ojo IP, Akintayo AA. Induction of labour in the developing Countries - an overview. J Med Sci 2013; 4 (7): 258-262.
13. Oyebode TA, Toma BO, Shambe IH, Kahansim ML, Embu HY, Daru PH, Sagay AS. Induction of labour at Jos University Teaching Hospital Jos Nigeria: A four-year review. Int J Res Med Sci 2015: 3: 1942-1948
14.  Burodo AT, Ladan AA, Singh S, Ukwu EA, Hassan M, Nnadi DC et al. Outcome of induction of labour in a Tertiary Hospital in Northwestern Nigeria. J Gynaecol 2018; 3(4): 000167
15.  Bako BG, Obed JY, Sanusi I. Methods of induction of labour at the University of Maiduguri Teaching Hospital, Maiduguri: A 4-year Review. Niger J Med 2008; 17:139-142.
16. Ugwuoroko HC, Eleje GU, Okafor CG, Okechukwu ZC, Eke AC, Okoro CC, et al. Obstetric Outcome of Induction of Labour in a Tertiary Hospital in Nigeria: A Five-Year Retrospective Cross-Sectional Study. Int J Innov Res Med Sci 2023 July 7; 8(7): 235-240.
17. Lawani OL, Onyebuchi AK, Iyoke CA, Okafo CN, Aja LO. Obstetric outcome and significance of labour induction in a health resource poor setting. Obstet Gynaecol Int 2014; 2014.419621. 
18. Abisowo OY, Oyinyechi AJ, Olusegun AF, Oyedokun OY, Motunrayo AF, Abimbola OT. Feto-maternal outcome of induced versus spontaneous labour in a Nigerian Tertiary Maternity Unit. Trop J Obstet Gynaecol 2017;34(1):21–27.
19. Orji EO, Olabode TO. Comparative study of labour progress and delivery outcome among induced versus spontaneous labour in nulliparous women using modified WHO partograph. Nepal J Obstet Gynaecol 2008; 3(1): 24-28
20. Ekele BA, Oyetunji J. Induction of labour at Usman Dan Fodio Teaching Hospital Sokoto. Trop J Obstet Gynaecol 2002: 19:74-77
21. Ade-Ojo IP, Adelekan OE, Adeniyi OO, Olofinbiyi BA, Okunola TO, Adesisan AS et al. Obstetric outcomes of induction of labour in a Tertiary Hospital in Southwest Nigeria. Int J Med Sci Clin Res Rev 2023 Mar-Apr; 6(2): 355-360. 
22. Ibrahim I, Obilahi A, Ekine A. Safety of Induction of Labour in Niger Delta Region.        J Med Sci 2012; 2(6): 173-178.
23. Bello FA, Akinyotu OO. Predictors of successful induction of labour at a Tertiary Obstetric service in Southwest Nigeria. Trop J Obstet Gynaecol 2016; 33(2): 143-148. 
24. Chen W, Xue J, Peprah M, Wen S, Walker M, Gao Y, et al. A systematic review and network meta-analysis comparing the use of Foley catheters, misoprostol, and dinoprostone for cervical ripening in the induction of labour. Int J Obstet Gynaecol. 2016;123 (3):346–54. 
25. Beshir YM, Kure MA, Egata G, Roba KT. Outcome of Induction of Labour and associated factors among induced labours in public Hospitals of Harari Regional State, Eastern Ethiopia: A two years’ retrospective analysis. PLoS ONE 2021 Nov 9; 16(11): e0259723. doi: 10.1371/journal.pone.02359723. Lueth GD, Kebede A, Medhanyie AA. Prevalence, outcomes and associated factors of labor induction among women delivered at public hospitals of MEKELLE town- a hospital based cross sectional study. BMC Pregnancy and childbirth 2020 Apr 9; 20:1-10. 
26. Adu-Bonsaffoh K, Seffah J. Factors associated with adverse obstetric events following induction of labour: a retrospective study in a tertiary hospital in Ghana. Afri Health Sci 2022; 22(4): 348-356. DOI: 10.4314/ahs.v22i4.40 
27. Ekele BA, Nnadi DC, Gana MA, Shehu CE, Ahmed Y, Nwobodo EI. Misoprostol use for cervical ripening and induction of labour in a Nigerian teaching hospital. Niger J Clin Pract 2007; 10(3): 234-237
28. Ryberg J, Carlsson Y, Svensson M, Thurnstrṏm E, Svanvik T. Risk of uterine rupture in multiparous women after induction of labour with prostaglandins: A national population-based cohort study Int J Gynecol Obstet 2023; 00:1-7.