Incidence of stillbirth and perinatal mortality and their associated factors among women delivering at Harare Maternity Hospital, Zimbabwe: a cross-sectional retrospective analysis

BACKGROUND: Death of an infant in utero or at birth has always been a devastating experience for the mother and of concern in clinical practice. Infant mortality remains a challenge in the care of pregnant women worldwide, but particularly for developing countries and the need to understand contributory factors is crucial for addressing appropriate perinatal health. METHODS: Using information available in obstetric records for all deliveries (17,072 births) at Harare Maternity Hospital, Zimbabwe, we conducted a cross-sectional retrospective analysis of a one-year data, (1997-1998) to assess demographic and obstetric risk factors for stillbirth and early neonatal death. We estimated risk of stillbirth and early neonatal death for each potential risk factor. RESULTS: The annual frequency of stillbirth was 56 per 1,000 total births. Women delivering stillbirths and early neonatal deaths were less likely to receive prenatal care (adjusted relative risk [RR] = 2.54; 95% confidence intervals [CI] 2.19-2.94 and RR = 2.52; 95% CI 1.63-3.91), which for combined stillbirths and early neonatal deaths increased with increasing gestational age (Hazard Ratio [HR] = 3.98, HR = 7.49 at 28 and 40 weeks of gestation, respectively). Rural residence was associated with risk of infant dying in utero, (RR = 1.33; 95% CI 1.12-1.59), and the risk of death increased with increasing gestational age (HR = 1.04, HR = 1.69, at 28 and 40 weeks of gestation, respectively). Older maternal age was associated with risk of death (HR = 1.50; 95% CI 1.21-1.84). Stillbirths were less likely to be delivered by Cesarean section (RR = 0.64; 95% CI 0.51-0.79), but more likely to be delivered as breech (RR = 4.65; 95% CI 3.88-5.57, as were early neonatal deaths (RR = 3.38; 95% CI 1.64-6.96). CONCLUSION: The frequency of stillbirth, especially macerated, is high, 27 per 1000 total births. Early prenatal care could help reduce perinatal death linking the woman to the health care system, increasing the probability that she would seek timely emergency care that would reduce the likelihood of death of her infant in utero. Improved quality of obstetric care during labor and delivery may help reduce the number of fresh stillbirths and early neonatal deaths.     

Causes and consequences of recent increases in preterm birth among twins.

OBJECTIVE: To examine the causes and consequences of the recent increase in preterm birth among twins. METHODS: We studied all twin births among residents of the province of Nova Scotia, Canada, between 1988 and 1997. Rates of preterm birth, preterm labor induction, preterm cesarean, small-for-gestational age (SGA), respiratory distress syndrome (RDS), stillbirth, perinatal mortality, and infant mortality were compared between past and more recent years. Changes in perinatal mortality were examined using logistic regression to adjust for the effects of other determinants. RESULTS: The study included 2516 twin births (73 stillbirths and 2443 live births). The rate of preterm birth increased from 42.3% in 1988-1992 to 48.2% of twin live births in 1993-1997 (14% increase, P =.04). Twin live births born after preterm labor induction increased from 3.5% in 1988-1989 to 8.6% in 1996-1997 (P for trend =.007). Of live births between 34 and 36 weeks' gestation, the proportion born SGA decreased from 17.5% in 1988-1992 to 9.2% in 1993-1997 (P =.005). Over the same period, rates of prophylactic maternal steroid therapy increased substantially and rates of RDS declined. Perinatal mortality rates among pregnancies reaching 34 weeks decreased from 12.9 per 1000 total births in 1988-1992 to 4.2 per 1000 total births in 1993-1997 (P =.05). CONCLUSION: Increases in preterm labor induction appear to be responsible for the recent increase in preterm birth among twins. These changes have been accompanied by decreases in perinatal morbidity and mortality among twin pregnancies that reach 34 weeks' gestation.     

Birth weight discordancy and adverse perinatal outcomes among twin gestations in the United States: the effect of placental abruption

OBJECTIVE: We evaluated whether the relationship between birth weight discordancy of twins and stillbirth, neonatal deaths, and preterm births was modified by the presence of abruption. STUDY DESIGN: We used the 1995 to 1997 matched multiple birth file for United States twin births (n = 269287). Birth weight discordancy was defined as the ratio of the difference in birth weight of the heavier from the lighter twin to that of the heavier twin and was categorized as <5%, 5% to 9%, 10% to 14%, 15% to 19%, 20% to 29%, 30% to 39%, and >or=40%. We evaluated the risks of stillbirth (>or=20 weeks of gestation), neonatal deaths (within 28 days after birth), and preterm birth (< 32 weeks) in the presence and absence of abruption. Associations between birth weight discordancy and these perinatal outcomes were expressed as adjusted relative risks and were derived from multivariable logistic regression models, based on the method of generalized estimating equations. Risk of these outcomes were derived for each stratum of birth weight discordancy and abruption status, with the <5% birth weight discordancy, nonabruption status labeled as the reference group. All analyses were performed separately for same and different sex twins. RESULTS: A birth weight discordancy of >or=20% among same sex (adjusted relative risk, 1.2; 95% CI, 1.1, 1.4), and >or=40% among different sex twins (relative risk, 2.2; 95% CI, 1.7, 2.8) conferred increased risk for abruption. Among nonabruption births, a birth weight discordancy of >or=15% among same sex and >or=30% among different sex twins increased the risk of stillbirths, neonatal deaths, and preterm births. Among abruption births, however, the risks were increased even in the lowest birth weight discordancy category (<5%). The relative risks of stillbirths and neonatal deaths among abruption births were significantly higher for each birth weight discordancy group, both for same and different sex twins, compared with the reference group. The association between birth weight discordancy and preterm birth was not modified by either the presence or absence of abruption. CONCLUSION: Birth weight discordancy of >or=15% for same sex and >or=30% for different sex confer greatest risk of adverse perinatal outcomes in the absence of abruption. In the presence of placental abruption, these risks are further compounded. The results underscore the need for careful monitoring of twin pregnancies.     

Birth Centers in Australia: A National Population‐Based Study of Perinatal Mortality Associated with Giving Birth in a Birth Center

ABSTRACT: Background: Perinatal mortality is a rare outcome among babies born at term in developed countries after normal uncomplicated pregnancies; consequently, the numbers involved in large databases of routinely collected statistics provide a meaningful evaluation of these uncommon events. The National Perinatal Data Collection records the place of birth and information on the outcomes of pregnancy and childbirth for all women who give birth each year in Australia. Our objective was to describe the perinatal mortality associated with giving birth in “alongside hospital” birth centers in Australia during 1999 to 2002 using nationally collected data. Methods: This population‐based study included all 1,001,249 women who gave birth in Australia during 1999 to 2002. Of these women, 21,800 (2.18%) gave birth in a birth center. Selected perinatal outcomes (including stillbirths and neonatal deaths) were described for the 4‐year study period separately for first‐time mothers and for women having a second or subsequent birth. A further comparison was made between deaths of low‐risk term babies born in hospitals compared with deaths of term babies born in birth centers. Results: The total perinatal death rate attributed to birth centers was significantly lower than that attributed to hospitals (1.51/1,000 vs 10.03/1,000). The perinatal mortality rate among term births to primiparas in birth centers compared with term births among low‐risk primiparas in hospitals was 1.4 versus 1.9 per 1,000; the perinatal mortality rate among term births to multiparas in birth centers compared with term births among low‐risk multiparas in hospitals was 0.6 versus 1.6 per 1,000. Conclusions: This study using Australian national data showed that the overall rate of perinatal mortality was lower in alongside hospital birth centers than in hospitals irrespective of the mother’s parity. (BIRTH 34:3 September 2007)     

Determinants of perinatal mortality in Nigeria

Objective

To determine risk factors for perinatal mortality among hospital-based deliveries in Nigeria.

Methods

The WHO Global Maternal and Perinatal Health Survey was implemented in Nigeria as a first step in establishing a global system for monitoring maternal and perinatal health. Twenty-one health facilities with more than 1000 deliveries annually were selected by a stratified multistage cluster sampling strategy. Information was recorded on all women who delivered and their neonates within a 3-month period.

Results

Overall, there were 9208 deliveries, comprising 8526 live births, 369 fresh stillbirths, 282 macerated stillbirths, 70 early neonatal deaths, and 721 perinatal deaths. The stillbirth and perinatal mortality rates were, respectively, 71 and 78 per 1000 deliveries; the early neonatal death rate was 8 per 1000 live births. Approximately 10% of all newborns weighed less than 2500 g, and 12.3% were born at less than 37 weeks of gestation. Predictors of perinatal mortality were mother's age, lack of prenatal care, unbooked status, prematurity, and birth asphyxia.

Conclusion

The perinatal mortality rate remains unacceptably high in Nigeria. Fresh stillbirth accounted for most perinatal deaths. Interventions to improve the utilization and quality of prenatal care, in addition to the quality of intrapartum care, would considerably reduce perinatal death.     

Growth retardation, size at birth and perinatal mortality in twin pregnancy

The records of 194 consecutive pairs of twins were reviewed. Univariate and multivariate analyses of relative risks (RR) of perinatal death were performed. Perinatal mortality rate was higher in small-for-gestational-age twins and in fetuses with discordancy in size at birth more than 20% and 25%. The RR of perinatal death for small-for-gestational-age twins was 4.8 (2.74-8.42 95% CI). For intertwin birth-weight percent differences of 20% and 25%, the RR was 5.48 (3.2-9.38 95% CI) and 7.2 (3.87-13.42 95% CI). Population mortality attributable risk in the two populations (10.36% and 14.5%, respectively) demonstrates the importance of the prenatal assessment of the respective size of twins in preventing perinatal death.     

Total perinatal wastage. A clarification of priorities

The pregnancy outcome of 16,971 women carrying 17,352 living fetuses after 16 weeks gestation was studied. As well as recording perinatal deaths, all losses before 28 weeks and up to one year after delivery were recorded to give a total perinatal wastage rate of 21.6 per 1000 fetuses alive at 16 weeks compared with a perinatal mortality rate (stillbirths plus early neonatal deaths) of 7.8 per 1000 births. All deaths were then classified according to pathological sub-groups. The concept of auditing perinatal care using perinatal mortality was then compared with that using total perinatal wastage.     

Systematic multidisciplinary approach to reporting perinatal mortality: Lessons from a five-year regional review

Background:  Because of differences in reporting criteria throughout the world, comparing perinatal mortality rates and identifying areas of concern can be complicated and imprecise.
Aims:  To detail the systematic approach to reporting perinatal deaths and to identify any significant differences in outcomes in the Australian Capital Territory (ACT).
Methods:  Review of perinatal deaths from 2001 to 2005 in the ACT using the Australian and New Zealand Antecedent Classification of Perinatal Mortality (ANZACPM) and the Australian and New Zealand Neonatal Death Classification (ANZNDC) systems.
Results:  ACT residents' perinatal mortality rate was 10.6 per 1000 total births, fetal death rate 7.5 per 1000 total births and neonatal death rate 3.2 per 1000 live births. The three leading antecedent causes of perinatal death were congenital anomalies, spontaneous preterm birth and unexplained antepartum death. The three leading causes of neonatal death were extreme prematurity, cardiorespiratory disorders and congenital anomalies. Multiple births attributed to 20% (65 of 321) of perinatal deaths. Perinatal autopsy was performed in 50% of cases, but in only 64% of unexplained antepartum deaths.
Conclusions:  Causes of perinatal death for the ACT and surrounding New South Wales region are similar to other states using this classification system. The following are considered important lessons to promote accurate perinatal mortality reporting: (i) a universal reporting system for Australia utilising a multidisciplinary team; (ii) a high perinatal autopsy rate, especially in the critical area of antepartum death with no identifiable cause; and (iii) standardised definitions for avoidability. Attention to these areas may prompt further research and changes in practice to further reduce perinatal mortality.     

Comparison of outcomes of perinatal care in Slovakia and the UK

Objective

To investigate whether there are differences in maternal and perinatal outcomes between Slovakia and the UK, and whether any observed variations can be attributed to differences in perinatal care.

Methods

Data on outcomes of perinatal care in Slovakia and the UK between 2006 and 2010 were compared. Perinatal mortality figures included stillbirths weighing 1000 g or more and early neonatal deaths.

Results

In Slovakia, the perinatal mortality rate was significantly higher than that in the UK (RR 1.12; 95% CI, 1.06–1.18). Cesarean delivery was significantly more frequent in Slovakia (RR 1.05; 95% CI, 1.05–1.06); instrumental vaginal delivery was less frequent (ventouse delivery, RR 0.20; 95% CI, 0.19–0.21; forceps delivery, RR 0.09; 95% CI, 0.09–0.10). Episiotomy and peripartum hysterectomy were performed more often in Slovakia (episiotomy, RR 4.10; 95% CI, 4.07–4.12; peripartum hysterectomy, RR 2.02; 95% CI 1.65–2.47). The incidence of eclampsia was significantly higher in Slovakia (RR 1.60; 95% CI, 1.26–2.04). There were no significant differences in the rates of maternal death.

Conclusion

Perinatal care outcomes and intervention rates differ between Slovakia and UK. This may be explained by differences in outcome definitions, perinatal care, and official encouragement of medical complaints.     

Total perinatal wastage. A clarification of priorities

Summary. The pregrmncy outcome of 16 971 women carrying 17 352 living fetuses after 16 weeks gestation was studied. As well as recording perinatal deaths, all losses before 28 weeks and up to one year after delivery were recorded to give a total perinatal wastage rate of 21.6 per 1000 fetuses alive at 16 weeks compared with a perinatal mortality rate (stillbirths plus early neonatal deaths) of 7.8 per 1000 births. All deaths were then classified according to pathological sub-groups. The concept of auditing perinatal care using perinatal mortality was then compared with that using total perinatal wastage.     

ENC training reduces perinatal mortality in Karnataka,India

Objective: To evaluate the effect of World Health Organization Essential Newborn Care course and the American Academy of Pediatrics Neonatal Resuscitation Program training on perinatal mortality in rural India. Methods: This study was part of a multi-country prospective, community-based cluster randomized controlled trial. Birth, 7-day and 28-day neonatal outcomes for all women with pregnancies greater than 28 weeks in the 26 study communities in Karnataka, India were included. Mortality rates pre- and post-Essential Newborn Care training were collected prospectively and then communities randomized to either receive neonatal resuscitation or refresher newborn care training in the control clusters. Results: Consent was obtained on 99% of the 25,096 births. Perinatal mortality for infants ≥500 g decreased from 52 to 36/1000 after newborn care training (RR 0.7; 95% CI 0.5, 0.9); stillbirth decreased from 23 to 14/1000 (RR 0.62; 95% CI 0.46, 0.83) and early neonatal mortality decreased from 29 to 22/1000 (RR 0.74; 95% CI 0.53, 1.03). Mortality was not reduced further with resuscitation training. Conclusions: Using a pre–post design, World Health Organization Essential Newborn Care community birth attendant training resulted in a significant reduction in perinatal mortality. In low-resource settings, the newborn care training package appears to be an effective intervention to decrease perinatal mortality.     

When Do Perinatal Deaths in Multiple Pregnancies Occur?

Perinatal mortality for multiple pregnancy remains at least 5 times the rate for singleton births. The major causes are neonatal deaths due to gross immaturity before 30 weeks' gestation, and stillbirths due to intrauterine growth retardation at all gestations, but especially after 32 weeks. Sixty four per cent of perinatal losses before 30 weeks' gestation occur before 26 weeks, highlighting the need to commence prophylactic measures earlier than usually recommended. The perinatal mortality in infants in multiple births weighing more than 2,500g is the same as that of singletons, but is 10 times this rate in multiple births weighing between 500g and 2,500g. Because the stillbirth rate in twins proceeding beyond 38 weeks' gestation is 3 times that of singleton births, elective termination of pregnancy is recommended if spontaneous labour has not occurred by this time.     

Declining perinatal mortality in Finland between 1987 and 1994: Contribution of different subgroups

Objective: To examine the extent to which the decline in perinatal mortality is attributable to some subgroups, especially to certain birthweight or gestation groups. Study Design: A register study using the Finnish Medical Birth Register for years 1987 to 1994. Results: Of the overall reduction in perinatal mortality from 8.8 to 6.7 per 1000 births, 78% was due to stillbirths, compared with 22% due to early neonatal deaths. The decline in mortality among infants who weighed under 1500 g at birth was the major contributor (62%) to the overall reduction in perinatal mortality. The largest decline in mortality in the stillbirth group occurred among those weighing < 1000 g, while for early neonatal deaths the group most affected weighed 1000-1499 g. A similar pattern emerged when the gestation-week groups were examined. Conclusion: The decline in perinatal mortality is attributable to stillbirths of very low birthweight. The most likely explanations for this result are the improved antenatal and neonatal care and the wider use of malformation screening.     

Clinical causes and classification of perinatal mortality in Lagos

Perinatal deaths in singleton births at the Lagos University Teaching Hospital during a 5-year period were reviewed. Causes of deaths were classified into eight groups using a modified form of the Aberdeen classification. Perinatal mortality was high (42.5/1000 total births). The stillbirth rate was 32.5/1000 total births. The major causes of perinatal mortality were trauma (30.5%), low birth weight (23.9%), hemorrhage (13.7%), toxemia of pregnancy (10.3%) and mature, cause unknown (10%). Congenital malformation (4.3%) was not a major cause of perinatal deaths in this study.     

Mode of delivery and the risk of delivery-related perinatal death among twins at term: a retrospective cohort study of 8073 births

OBJECTIVE: To determine the risk of perinatal death among twins born at term in relation to mode of delivery. DESIGN: Retrospective cohort study. SETTING: Scotland 1985-2001. POPULATION: All twin births at or after 36 weeks of gestation, excluding antepartum stillbirths and perinatal deaths due to congenital abnormality (n= 8073). METHODS: The outcome of first and second twins was compared using McNemar's test and the outcome of twin pairs in relation to mode of delivery was compared using exact logistic regression. MAIN OUTCOME MEASURES: Intrapartum stillbirth or neonatal death of either twin. RESULTS: Overall, there were six deaths of first twins and 30 deaths of second twins (OR for second twin 5.00, 95% CI 2.00-14.70). The odds ratio for death of the second twin due to intrapartum anoxia was 21 (95% CI 3.4-868.5). The associations were similar for twins delivered following induction of labour and for sex discordant twins. However, there was no association between birth order and the risk of death among 1472 deliveries by planned caesarean section. There was death of either twin among 2 of 1472 (0.14%) deliveries by planned caesarean section and 34 of 6601 (0.52%) deliveries by other means (P= 0.05, odds ratio for planned caesarean section 0.26 [95% CI 0.03-1.03]). The association was similar when adjusted for potential confounders. Assuming causality, we estimate that 264 caesarean deliveries (95% CI 158-808) would be required to prevent each death. CONCLUSION: Planned caesarean section may reduce the risk of perinatal death of twins at term by approximately 75% compared with attempting vaginal birth. This is principally due to reducing the risk of death of the second twin due to intrapartum anoxia.     

The impact of route of delivery and presentation on twin neonatal and infant mortality: a population-based study in the USA, 1995-97.

OBJECTIVE: We examined whether the route of delivery for near-term (> or = 34 weeks' gestation) twins, as candidates for vaginal delivery, affected neonatal and infant mortality rates. We further evaluated whether these mortality rates were modified by fetal presentation. METHODS: A population-based retrospective cohort study based on the matched multiple births data in the USA (1995-97) was performed. Analyses were restricted to non-malformed liveborn twins delivered at (> or = 34 weeks' gestation. Twins with breech-breech and breech-vertex presentations were excluded, since they are not candidates for vaginal delivery. Neonatal mortality rates (death within the first 27 days) and post-neonatal mortality rates (death between 28 and 365 days) per 1000 twin live births, by route of delivery and fetal presentation, were derived. The associations between neonatal mortality, post-neonatal mortality and the route of delivery for vertex-breech versus vertex-vertex presentations were expressed based on relative risks (RR) and 95% confidence intervals (CI) derived from logistic regression models based on the method of generalized estimating equations. RESULTS: Of the 177,622 twins analyzed, 87% (n = 154,531) presented as vertex-vertex. Fifty-five per cent (n = 97,692) of twins were both delivered vaginally, 41% (n = 72,825) were both delivered by Cesarean section and, of the remaining 4% (n = 7,105), the first twin was delivered vaginally and the second by Cesarean section. Twins with vertex-breech presentations delivered by Cesarean-cesarean sections, as well as those with vertex-vertex presentations delivered vaginally, had the lowest neonatal mortality rate (1.6 per 1000 live births). The highest neonatal mortality rate in the vertex-breech pairs occurred with vaginal-Cesarean deliveries (2.7 per 1000 live births). Among twins with vertex-vertex presentations, twins delivered via the vaginal-Cesarean route experienced the highest neonatal mortality (3.8 per 1000 live births). The RR for neonatal mortality in this group was 2.24 (95% CI 1.35, 3.72) compared with twins both delivered vaginally. CONCLUSION: Route of delivery and fetal presentation both confer an impact on twin infant mortality rates. Strategies to reduce discordant routes in complicated vaginal deliveries may lead to improved neonatal survival.     

Placental characteristics of monochorionic diamniotic twin pregnancies in relation to perinatal outcome

To study placental characteristics in relation to perinatal outcome in 150 pairs of monochorionic diamniotic (MCDA) twins. Between January 1998 and January 2007 150 pairs of MCDA twins were delivered in the University Medical Center, Utrecht, The Netherlands. Mortality, neonatal morbidity and birth weight discordancy were studied in relation to type of anastomoses, type and distance between cord insertions and placental sharing. From 14 weeks onwards, there were 45 (15.0%) perinatal deaths. We found no clear relationship between perinatal mortality and type of anastomoses, distance between cord insertions and placental sharing. Perinatal mortality was significantly increased in the presence of velamentous cord insertion (OR 3.65, 95% CI 1.83-7.28). Data concerning neonatal morbidity were similar. TTTS occurred predominantly in the presence of AV-anastomoses without compensating superficial AA-anastomoses (p=0.005) and occurred more frequently in the presence of velamentous cord insertion (OR 1.79, 95% CI 0.94-3.44). Twins with unequal shared placentas had significantly more often severe birth weight discordancy, although only in the presence of AA-anastomoses (OR 4.09, 95% CI 1.74-9.63). If AA-anastomoses were absent in the unequally shared placenta, there was no relation between severe birth weight discordancy and unequal sharing of the placenta (OR 1.06, 95% CI 0.08-13.52). In MCDA twins, placental characteristics determine perinatal outcome, occurrence of TTTS and fetal growth. Prenatal identification of these characteristics by ultrasound may alter counselling and intensity of pregnancy surveillance.     

The changing pattern of perinatal mortality and causes of death in central Anatolian region of Turkey

In this study, the perinatal mortality is presented in 2009 compared to 1998. Changing patterns of the perinatal mortality rate (PNMR), the stillbirth rate (SBR), early neonatal mortality rate (ENMR) and the causes of the perinatal mortality in Zekai Tahir Burak Women’s Health Education and Research Hospital (ZTBH) were described. This is the largest maternity hospital of Ankara in the central Anatolian region of Turkey. The total deliveries were 22,777 and 18,567 in 1998 and 2009, respectively. PNMR was 27.7 per 1000, and SBR was 23.7 per 1000 total births. ENMR was 4 per 1000 in 1998. PNMR is 20.7 per 1000, and SBR was 16.3 per 1000 and ENMR was 4.6 per 1000 total births in 2009. It is important to know the causes of mortality. In this study, the causes of perinatal deaths were classified according to the Wigglesworth classification. Antepartum stillbirth (62.3%) was the most frequent cause in 1998. Perinatal asphyxia is the majority (46.6%) of the perinatal deaths in 2009. This study shows that even prenatal care is getting better, obstetric care as well as close follow-up throughout the intrapartum period and diminishing the preterm delivery rate is also important for preventing and reducing perinatal mortality.     

Estonian medical birth registry 1992–1994: Association of risk factors with perinatal mortality

Objective: To investigate the association of different maternal sociodemographic characteristics and infant sex with perinatal mortality among primiparas and multiparas. Study design: Analysis of routine data from the Estonian Medical Birth Registry covering the whole of Estonia. A total of 47 358 infants (including stillborns) with a birth weight 1000 g or more from 1992 through 1994 were studied. Perinatal mortality rate, crude odds ratio (OR) and adjusted OR (calculated by a logistic regression model) were used to evaluate the association. OR values were adjusted for maternal age at delivery, maternal ethnicity, educational level, residence, marital status, smoking status, history of previous abortion and infant sex. Results: The perinatal mortality rate was 12.2 per 1000 total births among primiparous and 14.3 among multiparous women. The highest adjusted ORs of perinatal deaths were found in older (35 years and over) primiparas (1.78; 95% confidence interval (CI 0.88-3.57)) and multiparas (1.81; 95% CI 1.29-2.55), in unmarried (single) primiparas (1.59; 95% CI 1.14-2.20) and multiparas (1.98; 95% CI 1.29-3.05), in smoking primiparas (1.69; 95% CI 1.09-2.63) and multiparas (1.51; 95% CI 1.02-2.25), and in multiparas with unknown smoking status (1.98; 95% CI 1.18-3.33). Conclusion: The study provides further evidence that perinatal mortality is positively associated with increased maternal age, unmarried (single) status and smoking.