|Year : 2018 | Volume
| Issue : 2 | Page : 74-80
Multiple pregnancy in Dubai Hospital in 2012: Prevalence and maternal, perinatal and neonatal outcomes
Heba Ismail Adan1, Shabnam Saquib2
1 Department of Obstetrics and Gynaecology, Latifa Hospital, Dubai, United Arab Emirates
2 Department of Obstetrics and Gynaecology, Dubai Hospital, Dubai, United Arab Emirates
|Date of Web Publication||26-Jun-2018|
Heba Ismail Adan
Department of Obstetrics and Gynaecology, Latifa Hospital, Dubai
United Arab Emirates
Source of Support: None, Conflict of Interest: None
Introduction: Twin and higher-order multiple pregnancies are becoming increasingly common in obstetric practice and are associated with significant morbidity for both mothers and fetuses. A study of this type had not been carried out in the Dubai Health Authority area, or in the UAE. Therefore data from studies such as this can provide important insights for obstetricians in this region. Objectives: The aim of this study was to determine the prevalence of multiple pregnancy in a Dubai hospital in 2012 and to analyse the adverse maternal, perinatal and neonatal outcomes associated with these pregnancies. Methods: This is a retrospective study involving all multiple pregnancies delivered at Dubai Hospital, Dubai, between 1 January 2012 and 31 December 2012. All multiple pregnancies at or beyond 24 weeks of gestation delivered at Dubai Hospital during the study period were included. Data for patients with multiple pregnancy and their babies were obtained from the maternity register in Dubai Hospital's labour ward and antenatal files after obtaining ethics approval from the Dubai Health Authority's Medical Research Committee. We used Microsoft Excel 2013 (Microsoft Corporation, Redmond, WA, USA) to organise the data collected from patient medical records. Excel was also used for statistical analysis and presentation of data in tabular and graphical form. Results: In total, there were 106 multiple pregnancies over the period – 97 twin and nine triplet pregnancies – giving a multiple birth rate of 64.3/1000 live births. This is higher than any other documented multiple birth rate in the world. The mean maternal age was 30.5 ± 5.3 years (standard deviation). The most common morbidity in these multiple pregnancies was prematurity (72.6%), as expected, followed by maternal diabetes mellitus (22.6%). However, excluding premature delivery, almost 60% of mothers had no associated morbidities. Half of the multiple pregnancies were spontaneous conceptions, and half were the result of infertility treatments such as ovulation induction. Around one-third (30%) were conceived by in vitro fertilisation procedures, including intracytoplasmic sperm injection. As expected, triplets were delivered more prematurely than twins: the mean gestational age at delivery was 34.3 ± 3.7 weeks for twins and 31.0 ± 3.5 weeks for triplets. Around three-quarters (72.6%) of deliveries were by caesarean section, with the main indication (32.1%) being maternal request, 25.5% were delivered vaginally, 0.9% were delivered instrumentally and 0.9% were delivered vaginally (fi rst twin) and by caesarean section (second twin). Most of the newborns (58.4%) were of low birth weight. The vast majority (93.2%) had a 5-min Apgar score of ≥7, but the Neonatal Intensive Care Unit admission rate was around 38%, with triplets more likely to be admitted than twins (76.9% of all triplets vs. 33.3% of all twins). Overall, the results suggest a multiple pregnancy prevalence rate much higher than that of other developed countries, such as the USA, and even higher than that of Nigeria, which currently has the highest twin birth rate in the world. Conclusion: The increasing burden of multiple pregnancy in the United Arab Emirates may be attributable to the increasing availability and affordability of assisted reproductive technologies. Multiple pregnancy is associated with greater risks to both mothers and foetuses than singleton pregnancy, which warrants greater awareness of associated complications.
Keywords: Dubai, multiple pregnancies, triplets, twins
|How to cite this article:|
Adan HI, Saquib S. Multiple pregnancy in Dubai Hospital in 2012: Prevalence and maternal, perinatal and neonatal outcomes. Hamdan Med J 2018;11:74-80
| Introduction|| |
Twin and higher-order multiple pregnancies are becoming increasingly common. Fertility services have had a major impact on the changing incidence of multiple pregnancies: the proliferation of fertility specialists practising in Dubai and neighbouring emirates has resulted in more multiple pregnancies. Consulting a fertility specialist after a relatively short period of trying for a baby is associated with social pressure to achieve pregnancy quickly, an abundance of private medical practices and a relatively high average income, all of which are found in the United Arab Emirates (UAE).
Currently, around one in four pregnancies achieved by in vitro fertilisation (IVF) results in the birth of twins. Although many twins are healthy, a high proportion of twins are very vulnerable at the beginning of their lives because they are born preterm and/or are of a low birth weight, which can result in poor outcomes. Such risks are enhanced in higher-order pregnancies (e.g., triplets and quadruplets), many of which are the results of multiple embryo transfers during fertility treatment, although the guidelines are now in place restricting the number of embryos that can be transferred in each trial.,
Literature reviews of existing research have already confirmed increased rates of maternal and perinatal morbidity and mortality in multiple pregnancies. However, a study of this type had not been carried out in the Dubai Health Authority area, or in the UAE, until now. As a result of the increasing number of multiple pregnancies here in the UAE, obstetricians are dealing regularly with high-risk pregnancies. Data from studies such as this can provide important insights for obstetricians. This study should also be useful for future research that compares obstetric and perinatal outcomes of multiple pregnancies in Dubai Hospital, Dubai, with those of other tertiary care centres in the UAE.
The aim of this study is to determine the prevalence of these high-risk pregnancies in Dubai Hospital and analyse maternal and perinatal outcomes.
Aims and objectives
- To determine the prevalence of multiple pregnancy in Dubai Hospital from 1 January 2012 to 31 December 2012
- To analyse the adverse maternal, perinatal and neonatal outcomes of these multiple pregnancies.
- Maternal/obstetric outcomes to be analysed:
- Hypertension (essential or gestational/pre-eclampsia)
- Diabetes mellitus (gestational or pre-existing)
- Preterm labour
- Intrauterine growth restriction (IUGR)
- Antepartum haemorrhage (APH)
- Post-partum haemorrhage (PPH)
- Twin-to-twin transfusion syndrome (TTTS)
- Twin reversed arterial perfusion (TRAP) sequence
Neonatal outcomes to be analysed:
- Birth weight
- Neonatal Intensive Care Unit (NICU) admission
- Apgar score.
- To analyse the demographic data about the study participants, including age, parity and nationality
- To determine the chorionicity of the multiple pregnancies included in the study
- To determine the gestational age at delivery and mode of delivery of the different orders of multiple pregnancies
- To determine the number of multiple pregnancies that were spontaneous conceptions and assisted conceptions (e.g. ovulation induction or IVF).
| Materials and Methods|| |
A retrospective, observational cohort study of multiple pregnancy was conducted at Dubai Hospital between 1 January 2012 and 31 December 2012. Dubai Hospital is a tertiary referral centre with around 4000 deliveries per year. All multiple pregnancies at or beyond 24 weeks of gestation delivered at Dubai Hospital during the study period were included. Multiple pregnancies delivered before foetal viability (i.e., before 24 weeks of gestation or with a birth weight of <500 g) were excluded.
Data for patients with multiple pregnancy and their babies were obtained from the maternity register in Dubai Hospital's labour ward and antenatal files after obtaining ethics approval from the Dubai Health Authority's Medical Research Committee.
The data that were recorded for each case included maternal age, nationality, parity, date of last menstrual period, obstetric history, medical history and obstetric complication during current pregnancy.
The following obstetric complications in these pregnancies were recorded:
- Hypertension (essential or gestational/pre-eclampsia)
- Diabetes mellitus (gestational or pre-existing)
- Preterm labour
The diagnostic criteria for TTTS were same-sex twins, IUGR in the donor twin, normal or large recipient twin size, abnormal bladder sizes and abnormal Doppler study results. Growth discordance was diagnosed if the difference in estimated foetal weight was >20%.
Gestational age was determined from the date of last menstrual period or by ultrasound before 20 weeks of gestation. Preterm birth was defined as delivery before 37 weeks of gestation, very preterm birth as delivery between 28 and 34 weeks of gestation and extreme preterm birth as delivery before 28 weeks of gestation.
Chorionicity was determined by ultrasonography during the antenatal period. Chorionicity of twins was classified as dichorionic diamniotic (DCDA), monochorionic diamniotic (MCDA) or monochorionic monoamniotic (MCMA) and of triplets as trichorionic triamniotic (TCTA) or dichorionic triamniotic (DCTA). There were no quadruplets or other higher-order multiple pregnancies in this study.
Mode of conception was classified as spontaneous, assisted with ovulation induction or assisted with reproductive technologies such as intracytoplasmic sperm injection (ICSI).
Neonatal outcomes measured were birth weight, Apgar score and admission to NICU.
Classification of birth weight is as follows:
- Normal = 2501–3500 g
- Low = 1501–2500 g
- Very low = 1001–1500 g
- Extremely low = 500–1000 g.
Apgar scores were classified as 5-min Apgar scores of <7 or ≥7.
We used Microsoft Excel 2013 (Microsoft Corporation, Redmond, WA, USA) to organise the data collected from patient medical records. Excel was also used for statistical analysis and presentation of data in tabular and graphical form.
Continuous variables are reported as means and standard deviation (SD). Categorical variables are reported as percentages. Chi-square tests were used to compare the categorical variables. P < 0.05 was considered statistically significant.
| Results|| |
There were 106 multiple pregnancies during this study period as shown in [Table 1]. Of these, 97 were twin pregnancies and nine were triplet pregnancies, totalling 221 foetuses. Of these, 218 foetuses were viable at birth. Of the three remaining foetuses, one was an acardiac twin affected by TRAP sequence, one was stillborn and one was a triplet with a birth weight of <500 g and considered an abortus. There were no higher-order multiple pregnancies in the study period and the total number of live births was 3388, resulting in a multiple birth rate of 64.3 per 1000 live births.
Since Dubai Hospital is a government hospital, 64.2% of the study population were Emiratis as shown in [Figure 1]. Almost two-thirds (63.2%) of the study participants population were aged 25–35 years and only 22.6% were aged >35 years as documented in [Figure 2]. The mean maternal age was 30.5 ± 5.3 years (SD). [Table 2] shows that more than half (51.9%) of the study participants were para 1–2, 36.8% were primigravidae (para 3–4) and only 3.8% were grand multiparas (para ≥5).
[Figure 3] shows that, in the twins group, 84.6% were DCDA, 11.3% were MCDA and 4.1% were MCMA. In the triplets group, 66.7% were TCTA and 33.3% were DCTA as shown in [Figure 4]. There were no monochorionic triplets during the study period.
As shown in [Figure 5], exactly half of the study population conceived without assistance and half conceived with infertility therapies – either ovulation induction (17.9%) or other assisted reproductive techniques such as ICSI or IVF (30.2%). The mode of conception could not be determined in two pregnancies owing to a lack of data.
[Table 3] shows the different morbidities in the study population. The most common morbidity was preterm delivery (72.6%) followed by maternal diabetes mellitus (22.6%). Excluding prematurity, 58.5% of mothers had no associated morbidities. APH and PPH were recorded in 5.7% and 3.8% of the patients, respectively. Growth discordance was recorded in 7.5% of the patients.
In total, 27.3% of the study population delivered at term and 43.4% delivered preterm (excluding very preterm and extremely preterm) as shown in [Figure 6]. The mean gestational age at delivery of twins was 34.3 ± 3.7 weeks. Of these, 29% reached term and 44% delivered preterm (34–36 6/7 weeks). In the triplets group, the mean gestational age at delivery was 31 ± 3.5 weeks (SD). None of the triplets reached term and most (56%) were born very preterm (28–33 6/7 weeks). The rate of prematurity was compared between twins and triplets: A significant relationship was seen between the degree of prematurity – whether preterm, very preterm or extremely preterm – and the order of multiple gestation (P = 0.035) [Table 4].
Overall, the most common mode of delivery in the study population was caesarean section (72.7%) as shown in [Figure 7]. There was no significant difference in mode of delivery between twins and triplets: the majority were delivered by caesarean section [Table 5]. Eight out of nine triplet pregnancies were delivered by caesarean section; the only set of triplets who were delivered vaginally was delivered at 24 weeks of gestation. The most frequent indication for caesarean section was maternal request (32%) followed by previous caesarean section (22%) as shown in [Table 6].
Low birth weight affected 59% of twins and 52% of triplets. Very low birth weight and extremely low birth weight were significantly more common in triplets: 37% of triplets were of very low birth weight compared with 7% of twins, while 11% of triplets were of extremely low birth weight compared with 6% of twins. Mean birth weight was significantly different between twins and triplets (P = 0.003) [Table 7].
Apgar scores were generally good with 93% of newborns having an Apgar score of ≥7 at 5 min, as shown in [Table 8]. The overall admission rates to the NICU [Table 9] indicate that 60.6% of the newborns were not admitted to the NICU. As expected, triplets were more likely to be admitted to the NICU than twins (76.9% vs. 33.3%, respectively) as shown in [Table 10].
|Table 10: Admissions to Neonatal Intensive Care Unit - twins versus triplets|
Click here to view
| Discussion|| |
The multiple birth rate at Dubai Hospital between 1 January 2012 and 31 December 2012 was 64.3 per 1000 live births. This is higher than any other documented multiple birth rate in the world. For example, the multiple birth rate in the USA in 2011 was 34.6 per 1000 births. In addition, the rate in this study is higher than that of Nigeria, which has one of the highest twin rates in the world: around 54 per 1000 births.
It is well known that the prevalence of multiple pregnancy increases with maternal age, and this is primarily attributed to this age group's greater use of fertility services and higher levels of follicle-stimulating hormone. However, most of the patients in this study were aged 25–35 years. This is most likely to be because people in this region tend to be keen to conceive as soon as possible after marriage and to seek infertility treatment earlier and are therefore more likely to get pregnant earlier. Regarding maternal age and twinning, a US study published in 2011 demonstrated that twinning rates increased progressively with increasing maternal age and almost doubled for women aged >40 years compared with women aged <40 years.
It has been demonstrated that multiparity protects against adverse obstetric outcomes such as prematurity, low birth weight and caesarean delivery. One study concluded that increasing maternal age is not associated with NICU admission or composite foetal and neonatal mortality.
Studies have demonstrated that MCMA twins account for approximately 1% of all twins., In this study, the proportion of monochorionic twins was 4%.
Interestingly, one-third of the patients in this study conceived following IVF or ICSI procedures. This is attributable to the fact that fertility services are now readily available and easily accessible in the UAE. A 2012 study concluded that the method of conception does not have a negative impact on the course of pregnancy, risk of preterm delivery or obstetric outcome; neonatal complications in twins conceived both with and without assistance are primarily a result of prematurity.
Quite a significant proportion (58.5%) of the patients in this study had no associated morbidities, excluding prematurity. This may be explained by the relatively young age of the mothers. Regarding morbidities associated with multiple pregnancy, growth discordance was seen in approximately 7.5% of patients. Twin pregnancy is associated with a 10-fold risk of foetal growth restriction in comparison with singleton pregnancy. It is common for many twins to have a birth weight difference of around 15%. However, growth discordance between twins has been reported with variable prevalence owing to the varied criteria for discordance. Studies have demonstrated that the chance of having at least one growth-restricted twin is 34% in MCDA twins and 23% in DCDA twins. The neonatal outcome of growth-discordant twins is worse than that of growth-concordant twins.,
During the study period, the overall incidence of preterm delivery in Dubai Hospital was 9.5% (vs. 73% in multiple pregnancy); diabetes mellitus was recorded in 13.4% of all deliveries (vs. 23% of multiple pregnancies); hypertensive disorders were recorded in 3.9% of all deliveries (vs. 6.6% of multiple pregnancies) and PPH was recorded in 1.6% of all deliveries (vs. 3.8% of multiple pregnancies). Therefore, it can be understood that multiple pregnancy has a higher risk of most obstetric complications than single pregnancy, as already demonstrated in various studies worldwide. The high incidence of diabetes mellitus in this population may be attributable to the high prevalence of diabetes mellitus in the UAE.
A large 2011 study demonstrated that in Nigeria – which has the highest incidence of multiple pregnancy worldwide – multiple pregnancy is associated primarily with increased risk of hypertensive disorders, in addition to caesarean delivery, prematurity, low birth weight, low Apgar scores and NICU admission. Another study found that, among Mexican women pregnant with twins, the risk of pregnancy-induced hypertension was higher if the conception was assisted than if it was spontaneous.
More than half of the twins and almost all triplets are delivered preterm. We found an even higher rate of preterm delivery among twin pregnancies of about 70%. The perinatal mortality rate is approximately six times higher in multiple pregnancy than in singleton pregnancy, which is largely attributable to prematurity. In comparison with singleton pregnancy, twin pregnancy is associated with higher rates of gestational hypertension (relative risk [RR] 2.04) and pre-eclampsia (RR 2.62). APH is a major reason for hospital admission in multiple pregnancy. Velamentous cord insertion occurs 6–9 times more frequently in twin pregnancy, and vasa praevia, which can lead to APH, is also more likely. PPH is also more likely in multiple pregnancy as it is associated with overdistension of the uterus and caesarean section, both of which are more common in multiple pregnancy.
There was one case of TTTS and one case of TRAP sequence during the study period. TTTS occurred in an MCDA twin pregnancy following spontaneous conception delivered at 35 weeks of gestation. The infants, both of whom were male, weighed 1.6 and 2.4 kg at delivery and were admitted to the NICU. Worldwide, the incidence of TTTS is ≈ 10%–15%.
TRAP sequence is rare in monochorionic twins (affecting ≈ 1%). In our study, TRAP sequence occurred in an MCMA pregnancy following spontaneous conception. The patient was referred from another emirate to Dubai Hospital. The patient was delivered at 31 weeks and the outcome was a live twin with a birth weight of 1.6 kg and an acardiac twin with a birth weight of 1.4 kg. The live twin was admitted to the NICU.
In this study, gestational age at delivery was consistent with that reported in most studies conducted elsewhere: Twins were delivered at a mean gestational age of 34.3 ± 3.7 weeks and triplets at a mean gestational age of 31 ± 3.5 weeks. According to the Centers for Disease Control and Prevention's 2004 National Vital Statistics Reports, the average gestational age at delivery is 35.3 and 32 weeks for twins and triplets, respectively.
A study carried out in 2011 in France did not support routine delivery by caesarean section of twin pregnancies after 34 weeks of gestation if the presentation of the first twin is cephalic. On the other hand, a 2012 study of trends in caesarean section in twin pregnancies identified an association between increased caesarean birth rate, increased preterm births between 33 and 36 weeks and significantly reduced neonatal mortality. In this study, we noted that the patient population's preferred method of delivery in multiple pregnancy, even after counselling, was caesarean section.
Apgar scores at 5 min were generally good (≥7) for the majority (93%) of newborns in this study. This is similar to the finding of a 2011 study in Nigeria, which reported that only 8.5% of newborns had a 5-min Apgar score of <7.
This is a retrospective, observational, hospital-based study in a tertiary health-care centre, and therefore, obvious selection bias is unavoidable in that multiple gestations and high-risk pregnancies in general are managed at this hospital. In addition, recall bias is a possibility since data were gathered from the medical files of patients, whose honesty cannot be assumed regarding the sensitive subject of method of conception.
This study was carried out in a single tertiary care centre in Dubai. Because Dubai Hospital is a government-owned facility serving mainly UAE nationals; expatriates are more likely to be followed up and deliver in the vast number of private hospitals available in the city; therefore, the precise prevalence of multiple pregnancy and associated morbidities may be under- or over-estimated. The use of fertility services in Dubai Hospital is high particularly as it is free of charge to UAE nationals.
Although this study clearly illustrates the high prevalence of multiple pregnancies that doctors in Dubai are currently dealing with, further studies are required, involving most major government and private hospitals in the emirate of Dubai, to more accurately determine the burden of multiple pregnancy in the region.
| Conclusion|| |
Multi-foetal gestations are high-risk pregnancies increasingly encountered by obstetricians. This is largely attributable to the increased availability and affordability of infertility treatments, which appear to be especially true in Dubai.
Mothers pregnant with multiple foetuses are more likely to experience premature delivery, gestational diabetes mellitus, hypertensive disorders of pregnancy and obstetric haemorrhage. Foetal growth restriction is also more common than in singleton pregnancies. In addition, twins and other multiples are more likely to be of low or very low birth weight and therefore to be admitted to the NICU. Despite the advancement of neonatal care and intensive care facilities, appropriate management and follow-up of these pregnancies are essential to detect the onset of any complications.
We acknowledge the invaluable assistance of the Medical Records Department of Dubai Hospital in gathering the data needed to complete this study.
We also extend our gratitude and appreciation to the members of the Medical Research and Ethics Committee of the Dubai Health Authority, particularly Dr Mahera Abdulrahman, for guidance and input throughout this journey.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
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[Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5], [Figure 6], [Figure 7]
[Table 1], [Table 2], [Table 3], [Table 4], [Table 5], [Table 6], [Table 7], [Table 8], [Table 9], [Table 10]