Background
Improvement of the quality of obstetric and neonatal care is regarded as a prerequisite for preventing maternal and perinatal mortality [
1], especially in the post-millennium development goal era [
2]. In low-resource settings, substandard care accounts for significant numbers of maternal [
3] and neonatal deaths [
4], of which one-third include intrapartum stillbirth [
5]. In Tanzania, substandard care contributes to 6% of labour-related maternal deaths [
6] and 30% of perinatal mortality due to intrapartum asphyxia of mostly term deliveries [
7]. Numerous studies have suggested that there is a higher risk of adverse perinatal outcome during off-hours deliveries, i.e., during evening and night shifts, or at weekends [
8‐
15], compared to morning and afternoon office hours. These adverse outcomes include fetal injury [
9,
11], perinatal mortality [
8,
10] and early neonatal death (ENND) [
12,
13]. Other studies associated intrapartum fetal death [
13], and admission to neonatal intensive care unit (NICU) [
9], with births occurring during weekends. Conversely, other authors did not find any difference in the risk of poor perinatal outcome during off-hours [
16‐
18]. This evidence of high risk of adverse outcomes during off-hours has led to a general questioning of the quality of care and availability of access to skilled care providers, organization of work and availability of equipment, and supplies during off-hours.
One study, reporting on the circadian rhythm of the perinatal mortality rate throughout the week, found that the strongest determinants of the rate were associated with the selection of time of delivery of low birth weight fetuses in the afternoon hours based on obstetric risks, availability of obstetric and neonatal care, and chronobiologic behaviour [
19]. Another author associated increased adverse perinatal outcomes with increased rate of low umbilical artery pH in caesarean section (CS) during night shifts [
20]. However, umbilical blood gas analysis has also been found to be unreliable as a neonatal assessment tool for infants with an Apgar score of less than 7; and especially in high-risk pregnancies, including those delivered by CS, pre-term pregnancies and twin pregnancies [
21].
Stress and severe fatigue in care professionals that is related to long working hours compromises patients’ safety [
22‐
24]; however, the link between hours of work and patient safety is still unclear due to a lack of consistent reports of an association of sleep deprivation with medical error [
25,
26], and patient safety [
27]. Nonetheless, restricted on-call duty (50–80 working hours per week) has been reported to alleviate acute stress, fatigue, and loss of sleep [
28,
29]; and also has a positive impact on the quality of life of health care providers [
30], and, subsequently, can improve quality of care [
2]. Coincidental observations through attending hospital management and departmental meetings at Muhimbili National Hospital (MNH) highlighted low patient-to-caregiver ratio, periodic unanticipated high rates of deliveries, and limited supplies during night and evening shifts compared to morning shifts. Despite these discussions, no scientific evidence has been sought to confirm how the discrepancy between the demand and supply of obstetric care affects pregnancy outcomes.
Few researchers in developing countries [
31], and none we know of in Tanzania, have addressed the relationship between time of delivery and perinatal outcome. Lack of clear evidence of whether quality of care differs between time of delivery in relation to the structure and process of care compromises the overall effectiveness and efficiency of obstetric and neonatal interventions. Understanding the contributing factors for perinatal morbidities and mortalities is the key to reducing the number of adverse perinatal outcomes. Therefore, this study intended to answer the following research question: Is time of birth a predictor of adverse perinatal outcome? We estimated and compared the prevalence of adverse perinatal outcome across the three hospital working shifts, including the morning shift (7 am–2 pm), evening shift (2 pm–8 pm), and night shift (8 pm–7 am).
Methods
Study design and settings
We conducted a cross-sectional study at MNH in 2012. MNH is the highest referral hospital in Tanzania, and is a teaching hospital for Muhimbili University of Health and Allied Sciences (MUHAS). The hospital is situated in Dar es Salaam, which, according to the Tanzania Demographic Health Survey (TDHS 2010), has a population of about 4.5 million and an annual population growth rate of 4.3%. As one of the four consultant hospitals in Tanzania, MNH serves as a referral centre for the city of Dar es Salaam and the neighbouring coastal region. The annual number of deliveries in the hospital in 2012 was between about 8000 and 9000, of which 70% were self-referrals and hence the majority were also low-risk deliveries. Furthermore, out of 15 to 40 daily deliveries, 30 to 60% delivered by CS [
32]. The peak delivery period was March to April and the lowest delivery period was December to January. According to the birth registry, during 2012–2015, the MMR of women who delivered at MNH increased from 96 to 146/100,000 live births, and the fresh stillbirth ratio and early neonatal deaths decreased from 32/1000 to 26/1000 and from 27/1000 to 16/1000, respectively.
The obstetric wards were attended by 35 obstetricians, 25 obstetrics and gynecology residents, 2 registrars and 25 nurse midwives. Daily routines included a daily grand ward round for 24-h call reports, and major ward rounds in the labour room, obstetric ICU and admitting antenatal/postnatal ward. The outpatients’ clinic and elective obstetrics and gynecological surgeries were included among daily hospital routines. Doctors on call work for 24 h in a team comprised of one intern doctor, two residents (one in the labour ward and another in the obstetric theater), and one specialist and one consultant obstetrician who were mostly called for a second opinion or in case of emergency. The length of working hours for nurses was 8 h on the morning, 6 h on the evening and 11 h on the night shift. The nurse-parturient ratio averaged at 1:3–5 on the morning and evening shifts, but 1:6–8 on the night shifts. After a normal vaginal delivery, the mothers and babies were observed in hospital for 6–10 h. During this time, babies are vaccinated with BCG and polio vaccinations before being discharged. Babies delivered by CS or those who were sick were admitted to the neonatal ward, which also admits sick babies from other lower referral hospitals.
Study population and sampling
All parturients who delivered at MNH during the study period were identified from the midwifery registry and assessed for eligibility for recruitment. The exclusion criteria included patients that had a high risk of, or preexisting conditions that could lead to, poor maternal and/or perinatal outcomes: history of peripartum complication such as abruption placenta, placenta previa and eclampsia; and neonatal complications, including congenital anomalies and intrauterine fetal deaths confirmed antenatally by ultrasound or macerated stillbirths. All parturients who delivered <28 weeks of gestation, those who delivered twins, and those delivered by elective CS were also excluded.
Data collection
Data were collected for 5 months (June to December) from the partogram and case notes using a checklist and questionnaire. The variables of interest included: socio-demographic characteristics, such as age, marital status and level of education; obstetric characteristics, including parity, gestation age, source of admission, number of gestations, nature of labour and mode of delivery; and perinatal outcomes, including 5th minute Apgar scores, birth trauma, intrapartum stillbirth and early neonatal death. The data were collected by one of the researchers from the midwifery registry, however, in case of incomplete or ambiguous information from the registry, mothers were interviewed for clarification. Neonates who were admitted to the neonatal unit were followed up for seven days to document the early neonatal outcome. Alternatively, neonates who were not admitted after delivery were considered to have good outcomes, hence they were not followed up. Verification of the information recorded by questionnaire and checklist was completed daily, and hence, no case was excluded from the analysis.
Definition of terms
Adverse perinatal outcomes were defined as; Apgar score < 7 at 5 min, fresh stillbirth, early neonatal death, and physical birth trauma (including skull fracture, clavicle fracture, facial nerve palsy and brachial plexus injuries). The perinatal period commenced from 28 completed weeks of gestation or when the neonatal birth weight was above 500 g.
Early neonatal death was defined as death of a newborn within 7 days post-delivery. A stillbirth was defined as the delivery of a dead newborn within the perinatal period, and fresh stillbirth was the birth of a dead fetus without postmortem changes based on physical appearance, including blistered or peeled-off skin. A perinatal death was a neonatal death during the perinatal period and hence included stillbirths and early neonatal deaths. Primipara referred to a woman experiencing her first delivery, while Multipara was defined as a woman having her second or more delivery. A work shift meant a period of working hours within a 24-h cycle that was divided into a morning shift from 7 am to 2 pm (8 h), an evening shift from 2 pm to 7 pm (6 h), and a night shift from 7 pm to 7 am (12 h).
Data analysis
Data entry and cleaning was performed using Epi Info™ version 6, and then data were transferred to SPSS version 21.0 (SPSS, Armonk, NY: IBM Corporation) for statistical analyses. Data cleaning included removing typographic errors and duplicated information and amending incomplete or incongruent information using case notes and ward report logs and by interviewing the mother. Statistically significant differences in associations between maternal characteristics, mode of delivery and perinatal outcome to time of birth were assessed using chi-squared χ2 test for categorical variables, while Student’s t-test was used to assess continuous variables at a significance level of p = 0.05. Multiple logistic regression analysis was used to measure independent associations between selected predictors of adverse outcomes in relation to night shifts.
Results
During the study period, 3193 women delivered, out of which 557 women were excluded. Excluded participants were 327 who delivered by elective CS, and 9 with multiple gestations, of which 7 were twins and 2 were triplets. Other excluded women were 49 who had abruption placentas, and 99 who delivered before 28 weeks of gestation. One mother who had anencephalic fetus, 51 who had macerated stillbirths, and 22 with antenatal sonographic diagnosis of intra-uterine fetal deaths (IUFD), were also excluded. Therefore, the remaining 2636 deliveries were analysed (Table
1). Most of the deliveries occurred during the night shift (49%), and the evening shift had the least number of deliveries (21%). Thus, off-hours deliveries were nearly twice as likely to occur during the night shift (OR, 1.62; 95% CI, 1.50–1.72,
p < 0.001) but were less likely during the evening shift (OR, 0.58; 95% CI, 0.45–0.71,
p < 0.001).
Table 1
Percentage distribution of deliveries in three shifts within 24 h
Morning shift | 780 (30.0%) | 1 | |
Evening shift | 577 (21.0%) | 0.58 (0.45–0.71) | <0.001 |
Night shift | 1279 (49.0%) | 1.62(1.50–1.72) | <0.001 |
When comparing obstetric characteristics to timing of delivery (Table
2), the majority of deliveries were parturients aged between 20 and 35 years (80%), with a primary school education (60%) and were multiparas (65%). Furthermore, almost all deliveries were full-term delivery (92%). Most teenagers delivered during the morning shift (7.2%) compared to the evening (3.9%) and night shifts (2.3%). Parturients aged 35 years and above were nearly evenly distributed during the morning shift (14.1%) compared to the evening (13.5%) and night shifts (13.8%). Nearly the whole studied group had some level of formal education, i.e., at least primary education level, with the majority being multiparas and evenly distributed across the morning (63.5%), evening (68.3%) and night shifts (64.2%). Two-thirds of the deliveries came direct to the hospital from home, and nearly all of the remainder were referred from other hospitals. Referrals from other hospitals mostly delivered during the night shift (38.2%) compared to evening (33.3%) and morning shifts (29.9%). On the other hand, parturients arriving from home mostly delivered during the morning shift (68.7%) compared to those who delivered in the evening (65%) and night shifts (60.8%).
Table 2
Demographic and obstetric characteristics of according to time of birth
Age |
< 20 yrs | 56 (7.2) | 23 (3.9) | 29 (2.3) |
20-35 yrs | 614 (78.8) | 476 (82.5) | 1012 (83.8) |
35 + yrs | 110 (14.1) | 78 (13.5) | 176 (13.8) |
Education level |
No formal education | 10 (1.3) | 13 (2.2) | 19 (1.5) |
Primary School | 443 (56.8) | 338 (58.6) | 792 (62.0) |
Secondary School | 216 (27.7) | 146 (25.3) | 305 (23.8) |
College education | 111 (14.2) | 80 (13.9) | 163 (12.7) |
Parity |
Primipara | 276 (35.4) | 192 (33.3) | 458 (35.8) |
Multipara | 504 (64.6) | 385 (66.7) | 821 (64.2) |
Gestation age | | | |
36 weeks | 76 (9.7) | 48 (8.3) | 106 (8.3) |
37 + weeks | 704 (90.3) | 529 (91.7) | 1173 (91.7) |
Source of admission |
Referral another Hospital | 233 (29.9) | 192 (33.3) | 489 (38.2) |
From home | 536 (68.7) | 375 (65.0) | 777 (60.8) |
Antenatal admissions | 11 (1.4) | 109 (1.7) | 6 (1.0) |
When comparing the distribution of mode of deliveries (Table
3), half of the studied group delivered vaginally, and the majority of the remaining half by cesarean section (46%). Equal distribution of the remaining 4% of participants had abnormal breech delivery or were delivered by low cavity vacuum extraction (LCVE). No statistically significant difference was found in the rate of vaginal deliveries across the three shifts, i.e., the morning (52%), evening (52%) and night shifts (48%). Similarly, CS deliveries were evenly distributed during the morning (46%), evening (47%) and night shifts (48%) (
p = 0.07). However, most abnormal breech deliveries (1.6%) occurred during the night shift compared to morning (1%) and evening shifts (0.5%) (
p = 0.02). A similar pattern was observed for the LCVE deliveries, most of which (2.3%) were performed at night compared to the morning (1.8%) and evening (0.9%) shifts, (
p = 0.03)
Table 3
Percentage distribution of mode of delivery in three shifts within 24 h
SVD | 397 (51.0) | 300 (52.0) | 623 (48.6) | 0.1 |
C/S | 361 (46.2) | 269 (46.6) | 606 (47.5) | 0.07 |
ABD | 8 (1.0) | 3 (0.5) | 21 (1.6) | 0.02 |
LCVE | 14 (1.8) | 5 (0.9) | 29(2.3) | 0.03 |
Poor perinatal outcome was associated with 10% of neonatal distress (Apgar score < 7 at 5th min); 4% of early neonatal deaths and 6% of fresh stillbirths (Table
4). Night shift deliveries had twice the odds of poor perinatal outcome compared to morning shift deliveries (OR 1.48, 95% CI; 1.07–2.04,
p = 0.02, for neonatal distress; OR, 1.70; 95% CI, 1.07–2.72,
p = 0.03, for ENND; and OR, 1.95; 95% CI, 1.31–2.90,
p = 0.001, for FSB). No significant difference was found in the odds of poor perinatal outcome in the evening shift compared to the morning shift deliveries. Using multiple logistic regression analysis (Table
5), night shifts were independently associated with fresh stillbirths, antenatal admission from clinic or antenatal wards, referral from another hospital, and abnormal breech delivery (OR 1.9; 95% CI, 1.3–2.9;
p = 0.001, for FSB; OR 5.0; 95% CI 1.7–8.3;
p < 0.001, for antenatal admission; OR 1.2; 95% CI, 1.1–2.9;
p < 0.001, for referral from another hospital; and OR 1.6: 95% CI 1.02–2.6;
p = 0.004, for abnormal breech delivery(ABD)).
Table 4
Perinatal outcome of current delivery according to three shifts of 24 h
Apgar Score < 7 at 5thmin | 57 (7.3) | 1 | 44 (7.6) | 1.05 (0.09–1.58) | 0.83 | 134 (10.4) | 1.48 (1.07–2.04) | 0.02 |
END | 25 (3.2) | 1 | 18 (3.1) | 0.97 (0.53–1.79) | 0.93 | 69 (5.3) | 1.70 (1.07–2.72) | 0.03 |
FSB | 35 (4.4) | 1 | 29 (5.01) | 1.16 (0.69–1.93) | 0.65 | 105 (8.2%) | 1.95 (1.31–2.90) | 0.001 |
Table 5
Logistic regression of predictors of adverse outcome associated with the night shift
Fresh still birth | 1.9 (1.3–2.9) | 0.001 |
Maternal Age |
< 20 yrs | 1.0 (0.9–2.9) | 0.98 |
> 35 yrs | 1.0 (0.9–2.8) | 0.76 |
Primiparity | 1.0 (0.9–1.9) | 0.87 |
Antenatal admission | 5.0 (1.7–8.3) | <0.001 |
Referrals from another Hospital | 1.2 (1.1–2.9) | <0.001 |
Mode of delivery |
SVD | 1.0 (0.9–2.7) | 0.1 |
LCVE | 1.3 (0.9–3.3) | 0.21 |
ABD | 1.6 (1.02–2.6) | 0.04 |
Acknowledgements
The authors thank all mothers who agreed to participate in the study. The contribution of the obstetricians and nurses in the Department of Obstetrics and Gynaecology at MUHAS and MNH is highly appreciated.