Outcome of Labor in Twin Gestation at a Tertiary Institution in a Developing Nation : A 15-Year Review

C l i n M e d International Library Citation: Akinlaja O, Anorlu R (2014) Outcome of Labor in Twin Gestation at a Tertiary Institution in a Developing Nation: A 15-Year Review. Obstet Gynecol Cases Rev 1:001 Received: August 13, 2014: Accepted: September 15, 2014: Published: September 19, 2014 Copyright: © 2014 Akinlaja O. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. ISSN: 2377-9004 Akinlaja, Obstet Gynecol cases Rev 2014, 1:1


Introduction
Twin gestations are on the rise due to the use of fertility treatments and older maternal age at childbirth [1] and aside from macrosomia and post term pregnancy; it is associated with a higher rateof almost every potential pregnancy complication [2].A reported high incidence of 52/1000 in Ibadan and 21.1/1000 in Lagos has been noted in the Yoruba speaking area of southwestern Nigeria [3].
Variations in frequency are due almost entirely to different dizygotic twinning rate as the incidence of monozygotic twins is relatively stable worldwide at 3 to 5 per 1000 births [4].
Predisposing factors to twin pregnancy include race/tribe, maternal age, parity, previous history of twins, maternal weight and height, positive family history of twin gestation particularly on the maternal side and assisted reproductive methods [5][6][7].
Fetal complications arising from twin gestation include an increased risk of miscarriage, low birth weight, disappearing twin syndrome, intrauterine fetal death, malpresentation, intrauterine growth restriction, locked twins, retained 2 nd twin, congenital anomalies, cord prolapse with twin-twin transfusion and twin reversed arterial perfusion syndromes seen with monochorionic placentation while maternal complications include hyperemesis gravidarum, anemia, pregnancy induced hypertension, preeclampsia, eclampsia, polyhydramnios, preterm delivery, placental Previa, postpartum hemorrhage, increased prenatal admission and operative deliveries [8].
Despite the improvement in maternity and neonatal services, the high risk of perinatal morbidity and mortality associated makes it imperative for efforts to be intensified to ensure optimal care.This study describes our experience with twin pregnancy in a tertiary center in a developing nation with a high incidence rate of twins with a view to proffering the need for a more comprehensive approach to the management.The data was analyzed using simple percentages for categorical variables via the statistical package SPSS for MS Windows.

Result
During the period under review, there were a total of 28,472 deliveries, of which 642 were twin deliveries and 9 triplet deliveries.Twin deliveries accounted for about 1:44 of the total number of deliveries in our L&D during the study period.446 (69.5%) of the patients were booked while the remaining 196 (30.5%) were unbooked as shown in Table 1.
The age distribution of the patients ranged from 16 to 50 years (Table 2) with a mean of 29.2 years.The commonest age group was between 25 and 34 years; 449 (69.9%) while the peak occurrence was at 28 years; 71 (11.1%).Most of the patients were of low parity (0-2) accounting for 494 (77%) cases (Table 3).Delivery occurred mostly between 36 and 40 weeks-426 (67.2%) with the mean gestational age at delivery being 36.2 weeks.
Table 4 shows the presentation distribution with majority; 308 (47.9%) having both fetuses in cephalic presentation, 170 (26.5%) had the leading twin in cephalic presentation with twin II in breech presentation while 91(14.2%)presented with leading twin breech and the second twin cephalic.71(11.1%)had both fetuses in breech presentation with remaining 2 (0.3%) having other forms of presentation.
The male: female ratio was 650 (50.6%): 634 (49.4%).The mean birth weight of twin I being 2.43 kg while that of II was 2.3kg with the range of weight for twin I between 1.83kg and 3.24kg while twin II between 1.75 and 3.15kg, while the median weight for twin I was 2.35kg and 2.2Kg for twin II.95(14.7%)had a weight difference between twins I and II, more than or equal to 0.5 kg.The placentae weight varied between 600gm and 1.90 kg with an average of 1.60 kg.
There were a total of 269(41.9%)cases of operative deliveries of which there were 236 (36.8%) cases of delivery by caesarean section, 24 (3.74%) were elective while the remaining 212 (33.0%) were emergency caesarean section.16 (2.5%)had a vacuum extraction for either of the twin while 17 (2.7%) had forceps delivery.373(58%) had vaginal delivery as in Table 5.
Indications for caesarean section (Table 6) were mainly retained second twin, two previous caesarean sections, leading twin breech in a primigravid, cord prolapse, hypertensive disease of pregnancy, and failure to progress/prolonged labor.Hypertensive diseases of pregnancy and failure to progress accounted for the highest no of cesarean section; 64 (27.1%) and 55 (27.5%) of cases.353 (94.6%) of those who had vaginal delivery had a twin delivery interval less than 30 minutes while 20 (5.4%) had an interval greater than 30 minutes.357(55.6%)had an estimated postpartum blood loss less than 500mls while a significant 281(43.8%)had a loss between 500mls and 1 liter.4(0.6%) had an estimated blood loss greater than 1 liter; Table 7.There was a total of 85 (6.6%) perinatal loss.

Discussion
Although it is very difficult to assess the incidence of twin pregnancy in our environment due to a multiplicity of reasons, which include the fact that not all deliveries take place in the hospitals and in some cases proper records are not taken, the incidence of 1:44 deliveries obtained in this study still makes it a major obstetric issue considering the increased risk of obstetric complications as well as the increased perinatal and neonatal morbidity and mortality rates.
The incidence of 1: 44, obtained in this study is higher than 1:47 obtained in Lagos [9] and the 1:80 in Caucasians [3,4] but less than the 1 in 19 in western Nigeria [2].
The mean age at delivery was 29.2 years and the highest prevalence was seen between the ages 25 and 35 years, lower than the age group 30-35 years found in a study in France [10].It is however important to note that the single commonest occurrence in this study was at 28 years of age.
The patients were mainly of low parity (77%) as against previous studies where it has been shown that increasing maternal age and parity have a positive influence on the incidence of twinning.
Only 6% were grand multipara in this study, however, this might be reflecting the hospital referral population rather than the true rate in the populace.
The duration of pregnancy was between 36 and 40 weeks with a mean gestational age at delivery of 36.2 weeks, which is comparable to about 37 to 37.4 weeks found in previous studies [3,11].This is generally attributable to uterine over-distension as there is a belief that uterine contractions commence at a critical degree of myometrial stretch and then increase in frequency and strength to cause ultimately progressive cervical dilatation and labor.
The mean birth weight for twins I and II were 2.43 kg and 2.3kg  and these corresponded with previous studies where the mean birth weight of a twin had been found to be less than 2.5 kg [3].Increased preterm labor and deliveries as well as a higher incidence of fetal growth restriction found in twins might account for this.
In this study, 14.7% had a weight difference greater than 0.5 kg between twin I and II as compared to other studies [12] where a discordant growth of 10% had been detected between twin I and II and this might due to the unequal sharing of available maternally derived nutrients, reduced placental surface area for each of the two infants, the twin to twin transfusion syndrome or genetics.
The male: female ratio was about 1:1 comparable to previous studies and singleton gestations [11].
The presentation was mostly cephalic (74.4%) with both twins in cephalic presentation in about 47.9% of cases, comparable to other studies in which about 70% have the first twin presenting cephalic with between 40 and 45% of both fetuses being born by this presentation [8].
Cephalic-breech, breech-cephalic and breech-breech were: 26.5%, 14.2% and 11.1% comparable with 35%, 10% and 10% respectively in other studies (3) (10).A significant 14.2% had the leading twin presenting breech when compared with the 2-3% at term seen in singleton pregnancies [3].94.6% of patients who achieved vaginal delivery had a twin-twin delivery interval less than 30 minutes while only 5.4% had an interval greater than 30 minutes, though the optimal time interval between births is 10-30 minutes, with satisfactory fetal heart rate monitoring, greater delay may be quite safe.
An increased incidence of operative delivery (vaginal or abdominal), with a caesarean section rate of 36.8%with the attendant increased maternal morbidity and mortality is in comparison higher than the overall incidence of about 15-21% caesarean section rate found in most West African countries [13].
A significant 43.8% had estimated blood loss >500mls while 0.6% had an estimated blood loss> 1 liter and these might be accounted for by the increased incidence of uterine atony, retained placenta and operative delivery.
A perinatal mortality rate of 66 per 1000 births, lower than the 146.4 and 173.93 per 1000 births detected in Lagos and Ibadan in 1984 and 1971 respectively was found and this might be due to a higher number of our patients been booked, improved standard of obstetrics care and probably the hospital referral population.The figure was however still higher than 40.83 per 1000 births from singleton pregnancies and this might be due to the high incidence of preterm deliveries and low birth weight rather than twinning per se [3,4].

Conclusion
This study showed that there is still a high incidence of multiple pregnancies in our environment and it is associated with an increased occurrence of preterm delivery with it's sequelae of low birth weight and subsequent increased perinatal morbidity and mortality in addition to the increased incidence of operative delivery with its associated maternal complications.
A significant number of patients also had postpartum hemorrhage thereby highlighting the fact that multiple gestation still remains a serious obstetrics problem, however early diagnosis, appropriate antenatal, vigorous Intrapartum and postpartum care with the use of uterotonics and adequate neonatal care with prompt referral to well equipped centers manned by skilled attendants may assist in reducing this increased incidence of morbidity and mortality.

Table 3 :
Parity Distribution of Twin Pregnancy.

Table 4 :
Pattern of Presentation of Twins in Labour.

Table 5 :
Mode of Delivery.

Table 6 :
Indication for Caesarean Section.