Stillbirth rate and associated risk factors among 869 750 Latin American hospital births 1982-1986

Elevated risk of stillbirth in males: systematic review and meta-analysis of more than 30 million births

BACKGROUND

Stillbirth rates have changed little over the last decade, and a high proportion of cases are unexplained. This meta-analysis examined whether there are inequalities in stillbirth risks according to sex.

METHODS

A systematic review of the literature was conducted, and data were obtained on more than 30 million birth outcomes reported in observational studies. The pooled relative risk of stillbirth was estimated using random-effects models.

RESULTS

The crude mean rate (stillbirths/1,000 total births) was 6.23 for males and 5.74 for females. The pooled relative risk was 1.10 (95% confidence interval (CI): 1.07-1.13). The attributable fraction in the whole population was 4.2% (95% CI: 3.70-4.63), and the attributable fraction among male fetuses was 7.8% (95% CI: 7.0-8.66). Study populations from countries with known sex-biased sex selection issues had anomalous stillbirth sex ratios and higher overall stillbirth risks than other countries, reflecting increased mortality among females.

CONCLUSIONS

Risk of stillbirth in males is elevated by about 10%. The population-attributable risk is comparable to smoking and equates to approximately 100,000 stillbirths per year globally. The pattern is consistent across countries of varying incomes. Given current difficulties in reducing stillbirth rates, work to understand the causes of excess male risk is warranted. We recommend that stillbirths are routinely recorded by sex. This will also assist in exposing prenatal sex selection as elevated or equal risks of stillbirth in females would be readily apparent and could therefore be used to trigger investigation.

Preconception care: promoting reproductive planning

INTRODUCTION

Preconception care recognizes that many adolescent girls and young women will be thrust into motherhood without the knowledge, skills or support they need. Sixty million adolescents give birth each year worldwide, even though pregnancy in adolescence has mortality rates at least twice as high as pregnancy in women aged 20-29 years. Reproductive planning and contraceptive use can prevent unintended pregnancies, unsafe abortions and sexually-transmitted infections in adolescent girls and women. Smaller families also mean better nutrition and development opportunities, yet 222 million couples continue to lack access to modern contraception.

METHOD

A systematic review and meta-analysis of the evidence was conducted to ascertain the possible impact of preconception care for adolescents, women and couples of reproductive age on MNCH outcomes. A comprehensive strategy was used to search electronic reference libraries, and both observational and clinical controlled trials were included. Cross-referencing and a separate search strategy for each preconception risk and intervention ensured wider study capture.

RESULTS

Comprehensive interventions can prevent first pregnancy in adolescence by 15% and repeat adolescent pregnancy by 37%. Such interventions should address underlying social and community factors, include sexual and reproductive health services, contraceptive provision; personal development programs and emphasizes completion of education. Appropriate birth spacing (18-24 months from birth to next pregnancy compared to short intervals <6 months) can significantly lower maternal mortality, preterm births, stillbirths, low birth weight and early neonatal deaths.

CONCLUSION

Improving adolescent health and preventing adolescent pregnancy; and promotion of birth spacing through increasing correct and consistent use of effective contraception are fundamental to preconception care. Promoting reproductive planning on a wider scale is closely interlinked with the reliable provision of effective contraception, however, innovative strategies will need to be devised, or existing strategies such as community-based health workers and peer educators may be expanded, to encourage girls and women to plan their families.

Preconception care: delivery strategies and packages for care

The notion of preconception care aims to target the existing risks before pregnancy, whereby resources may be used to improve reproductive health and optimize knowledge before conceiving. The preconception period provides an opportunity to intervene earlier to optimize the health of potential mothers (and fathers) and to prevent harmful exposures from affecting the developing fetus. These interventions include birth spacing and preventing teenage pregnancy, promotion of contraceptive use, optimization of weight and micronutrient status, prevention and management of infectious diseases, and screening for and managing chronic conditions. Given existing interventions and the need to organize services to optimize delivery of care in a logical and effective manner, interventions are frequently co-packaged or bundled together. This paper highlights packages of preconception interventions that can be combined and co-delivered to women through various delivery channels and provides a logical framework for development of such packages in varying contexts.

Maternal antiretroviral use during pregnancy and infant congenital anomalies: the NISDI perinatal study

BACKGROUND

We evaluated the association between maternal antiretrovirals (ARVs) during pregnancy and infant congenital anomalies (CAs), utilizing data from the National Institute of Child Health and Human Development International Site Development Initiative Perinatal Study.

METHODS

The study population consisted of first singleton pregnancies on study, > or =20 weeks gestation, among women enrolled in NISDI from Argentina and Brazil who delivered between September 2002 and October 2007. CAs were defined as any major structural or chromosomal abnormality, or a cluster of 2 or more minor abnormalities, according to the conventions of the Antiretroviral Pregnancy Registry. CAs were identified from fetal ultrasound, study visit, and death reports. Prevalence rates [number of CAs per 100 live births (LBs)] were calculated for specific ARVs, classes of ARVs, and overall exposure to ARVs.

RESULTS

Of 1229 women enrolled, 995 pregnancy outcomes (974 LBs) met the inclusion criteria. Of these, 60 infants (59 LBs and 1 stillbirth) had at least 1 CA. The overall prevalence of CAs (per 100 LBs) was 6.2 [95% confidence interval (CI) 4.6 to 7.7]. The prevalence of CAs after first trimester ARVs (6.2; 95% CI 3.1 to 9.3) was similar to that after second (6.8; 95% CI 4.5 to 9.0) or third trimester (4.3; 95% CI 1.5 to 7.2) exposure. The rate of CAs identified within 7 days of delivery was 2.36 (95% CI 1.4 to 3.3).

CONCLUSIONS

The prevalence of CAs after first trimester exposure to ARVs was similar to that after second or third trimester exposure. Continued surveillance for CAs among children exposed to ARVs during gestation is needed.

Epidemiology of stillbirth and fetal central nervous system injury

The epidemiology of stillbirth and fetal central nervous system (CNS) injury is described with some emphasis on maternal and feto-placental risk factors. To maximize utility of the discussion and because it also represents the classical manifestation of fetal CNS injury, we have selected cerebral palsy (CP) to illustrate the epidemiologic aspects of injury to the fetal CNS in general. While trends in stillbirth rates have modestly decreased over time, those of CP seem to be increasing. Interestingly, both stillbirth and CP share traditional as well as emerging risk factors lending credence to the hypothesis that fetuses that would previously have been stillborn are increasingly surviving albeit with some form of morbidity. The existence of shared risk factors also suggests that in some cases of stillbirth fetal CNS injury precedes the in utero fetal demise. Pregnant women bearing these risk indicators represent potential candidates for appropriate and tailored protocols for antenatal fetal testing.

Maternal age and risk of stillbirth: a systematic review

BACKGROUND

The number of women who delay childbirth to their late 30s and beyond has increased significantly over the past several decades. Studies regarding the relation between older maternal age and the risk of stillbirth have yielded inconsistent conclusions. In this systematic review we explored whether older maternal age is associated with an increased risk of stillbirth.

METHODS

We searched MEDLINE, EMBASE and the Cochrane Database of Systematic Reviews for all relevant articles (original studies and systematic reviews) published up to Dec. 31, 2006. We included all cohort and case-control studies that measured the association between maternal age and risk of stillbirth. Two reviewers independently abstracted data from all included studies using a standardized data abstraction form. Methodologic and statistical heterogeneities were reviewed and tested.

RESULTS

We identified 913 unique citations, of which 31 retrospective cohort and 6 case-control studies met our inclusion criteria. In 24 (77%) of the 31 cohort studies and all 6 of the case-control studies, we found that greater maternal age was significantly associated with an increased risk of stillbirth; relative risks varied from 1.20 to 4.53 for older versus younger women. In the 14 studies that presented adjusted relative risk, we found no extensive change in the direction or magnitude of the relative risk after adjustment. We did not calculate a pooled relative risk because of the extreme methodologic heterogeneity among the individual studies.

INTERPRETATION

Women with advanced maternal age have an increased risk of stillbirth. However, the magnitude and mechanisms of the increased risk are not clear, and prospective studies are warranted.

Stillbirth rates in Peruvian populations at high altitude

OBJECTIVE

To compare the stillbirth rates in 4 cities at different altitudes in Peru.

METHODS

The stillbirth rates from a sample of 22,662 births recorded in the Perinatal Information System database were analyzed between 2005 and 2006 for the cities of Lima (150 m), Huancayo (3280 m), Cuzco (3430 m), and Puno (3850 m).

RESULTS

Stillbirths were higher at high altitude (>3000 m) (OR 4.82; CI, 3.05-7.72) compared with low altitude. The effect of altitude was observed after controlling for socioeconomic (OR 4.29; CI, 2.61-6.93), demographic and biological (OR 4.18; CI, 2.65-6.77), maternal health care (OR 4.72; CI, 2.96-7.61), and fetal factors (OR 3.96; CI, 2.48-6.45). Inhabitants from the southern Andes demonstrated a protective effect on stillbirth rate compared with the central Andes, which may be due to an ancestry effect with longer multigenerational residence in the southern Andes population.

CONCLUSION

Stillbirth rate is higher at high altitude compared with low altitude.

Does chronic mountain sickness (CMS) have perinatal origins?

Chronic mountain sickness (CMS) occurs in approximately 10% of male high-altitude residents. It is characterized by hypoventilation and hypoxemia but its underlying cause remains unknown. We hypothesized that CMS' origins reside in exaggerated perinatal hypoxia that serves, in turn, to impair the development of pulmonary structure and/or respiratory control. As a preliminary test, we asked if birth weights were low and other signs of perinatal hypoxia were present in 12 young men with excessive erythrocytosis (EE, Hb>or=18.3g/dL), a condition thought to be a preclinical phase of CMS. Their birth weights were uniformly low (2571+/-243g) and all but one demonstrated perinatal hypoxia as manifested either by being small for their gestational age (SGA, 8%), preterm (67%), born to a preeclamptic (PE) mother (50%), or diagnosed with neonatal hypoxia (83%). Impaired growth in utero has been shown to raise susceptibility to adult disease; these are the first data to demonstrate a possible influence of reduced fetal growth and/or exaggerated perinatal hypoxia on increasing the susceptibility to CMS. Future studies, with more detailed testing in larger samples of control as well as EE subjects, with longitudinal follow-up, are required to determine the role of perinatal hypoxia in the development of CMS.

Maternal age, parity, and reproductive outcome in captive chimpanzees (Pan troglodytes)

As early as the 1970s, it was suggested that nonhuman primates may serve as models of human reproductive senescence. In the present study, the reproductive outcomes of 1,255 pregnancies in captive chimpanzees (Pan troglodytes) were examined in relation to parity and its covariate, maternal age. The results show that the percentage of positive pregnancy outcomes was negatively correlated with increasing parity. In addition, spontaneous abortions, stillbirths, and caesarian sections (C-sections) were positively correlated with increasing parity. Maternal age, rather than parity, was found to be the most important predictor of negative birth outcome. This study supports research demonstrating reproductive decline and termination in nonhuman primates, and is the first to quantitatively account for this phenomenon in captive female chimpanzees.

Assessment of risk factors for stillbirth among pregnant women in Jamaica

A case - control study was conducted to assess the risk factors of stillbirth among pregnant women in Jamaica. A total of 314 women participated (160 with stillborn babies and 154 with live-born babies). A questionnaire designed to collect information on sociodemographic characteristics, antenatal care, medical and sexually transmitted disease (STD) history, method of delivery and infant birth and health status was administered to each woman. Medical records were reviewed to verify medical history. Six variables were found to be significant predictors of stillbirth by multivariate logistic regression. Low birth weight (OR = 4.3, CI = 2.4 - 7.7), complications during pregnancy or delivery (OR = .19, CI = 0.09 - 0.41), method of delivery (caesarean section; OR = 7.2, CI = 1.6 - 33.2), number of living children (OR = 0.54, CI = 0.40 - 0.73), number of antenatal visits (less than three; OR = 2.0, CI = 1.3 - 3.1), and presence of unfavourable and /or adverse fetal outcome (OR = 4.0, CI = 1.8 - 9.2) were found to be associated with stillbirth. These findings have important implications in establishing policies for prenatal care in Jamaica.

Can clinical risk factors for late stillbirth in West Africa be detected during antenatal care or only during labour?

BACKGROUND

Recent studies have shown that the most important risk factors for perinatal mortality in developing countries are not detectable during antenatal care but can be observed only shortly before or during labour. Although 60% of perinatal deaths in these countries are stillbirths, few epidemiological studies focus on them. We tested the hypothesis that the risk factors for late stillbirth in West Africa are detectable principally shortly before or during labour.

METHODS

Data came from a prospective population-based study (the MOMA survey) that collected information about 20 326 pregnant women in seven areas, primarily urban, in West Africa.

RESULTS

There were 19 870 singleton births. The stillbirth rate was 25.9 per 1000 total births (95% CI: 23.7-28.1). In the crude analysis, after adjustment and consideration of prevalence, the principal risk factors for late stillbirth were: late antenatal or intrapartum vaginal bleeding, intrapartum hypertension, dystocia, and infection. Other risk factors were: maternal height (<150 cm), maternal age (>35 years), previous stillbirths, hypertension at the 8-month antenatal visit and number of antenatal visits (<2).

CONCLUSIONS

The principal risk factors for late stillbirth observed in our study could be detected only in the late antenatal and intrapartum period. These results highlight the potential benefits of partograph use. They need to be confirmed by studies incorporating continuous intrapartum fetal monitoring.

Gestational diabetes mellitus and fetal death in Mozambique: an incident case-referent study

BACKGROUND

Third trimester fetal death is a common problem in Mozambique, occurring in approximately 5% of parturient women.

OBJECTIVE

To elucidate the magnitude of the gestational diabetes mellitus problem, and to estimate its prevalence in a group of women with unexplained late fetal deaths and in women with live fetuses (referents).

METHODS

An incident case-referent study of 109 pregnant Mozambican women with fetal deaths and 110 women delivering liveborns, regarding fasting B-glucose, oral glucose tolerance test and glycosylated hemoglobin.

RESULT

The difference in gestational diabetes mellitus prevalence in the two groups is not significant. The prevalence of gestational diabetes mellitus was high in both groups: 11% and 7%, respectively.

Birth order and left-handedness revisited: some recent findings in chimpanzees (Pan troglodytes) and their implications for developmental and evolutionary models of human handedness

This paper examines the relationship between parity, pregnancy outcome, and handedness in a sample of captive chimpanzees (Pan troglodytes). The relation between parity, maternal age and positive or negative pregnancy outcome was assessed from life history data for 536 chimpanzees housed at the Yerkes Regional Primate Research Center. The incidences of negative pregnancy outcome (notably spontaneous abortions and stillbirths) were significantly higher in parities of 8 or higher compared to all other parities. In a sub-sample of 165 chimpanzees, the relation between parity, maternal age and handedness was assessed to determine whether left handedness may serve as a marker of prenatal pathology. These analyses indicated that left-handedness was more prevalent in 1st and 8 or higher parities compared to parities between 2 and 7, respectively. Possible prenatal hormonal and periparturitional factors are discussed as possible mechanisms for the observed findings.

Determinants of stillbirth mortality in Greece

A population-based case-control study of the determinants of stillbirths was conducted in Greece from 1989 to 1991. All reported stillbirths after 28 weeks of pregnancy (N = 2,006) during the three year study period comprised the case group. The control group derived from random sampling of 10% of all livebirths in Greece, during the same period (N = 30,705). The data were analysed by modelling through multiple logistic regression. The adjusted relative risk of stillbirth was significantly higher for males compared to females. A statistically significant monotonic increase in relative risk was observed with shorter gestational age, low maternal education, and older maternal age. Birthweight and parity showed a statistically significant U-shaped association with stillbirth risk, with a higher risk being observed among both low and high birthweight deliveries, as well as among primiparous or multiparous (4+) mothers. Positive associations of stillbirth with multiple births, out-of-wedlock marriage and non-Greek-orthodox maternal religion were noted in crude analyses, but these associations almost disappeared in logistic regression model. Maternal urban or rural residence showed no relation to risk. Overall, the prospective risk of stillbirth after the 24th week of gestation in Greece has been estimated to be higher than that in Japan (a more developed country) with more than 40% of stillbirths occurring after the 36th week of pregnancy.

Perinatal mortality at the North West Armed Forces Hospital, Tabuk, Saudi Arabia and the potential benefits of the biophysical profile score

Relatively little information is available in the literature regarding perinatal mortality in Saudi Arabia and none concerning the value of a full fetal assessment screening program in its reduction. This study analyzes all deliveries with a birth weight of greater than 500 grams at the North West Armed Forces Hospital (NWAFH) for the year 1992. It investigates the causes of perinatal death, ascertaining those which could potentially have been avoided and assessing the role which a fetal assessment screening program might have played in its reduction. There were 4387 babies born during this period. The combined perinatal mortality rate was 16.3%. Of these, 6.5% comprised babies weighing less than 1000 grams. Fifty-one (71%) of the deaths occurred among high risk patients and of these, 28 might have been saved had they been referred for fetal assessment screening. This study shows that the perinatal mortality rate at the NWAFH is comparable to figures obtained in other major centers in the country and that the introduction of a fetal assessment screening program could potentially result in a decrease in the perinatal mortality rate to less than 10/1000.

A perinatal audit of stillbirths in a teaching hospital in Hong Kong

In a 5-year period, the stillbirth rate in a teaching hospital in Hong Kong was 4.4 per 1,000 total births, which accounted for 61% of the perinatal deaths. The stillbirth rate was 5.8 times higher in twin pregnancies, and 17 times higher in triplet pregnancies. One quarter of the patients were nonbooked, and 14.5% had no antenatal care. The stillbirth rates were 3.8 and 8.0 per 1,000 among the booked and nonbooked cases respectively. The major causes of stillbirths were congenital abnormalities, haemoglobin Bart disease, abruptio placentae and gestational diabetes. No specific cause could be found in 46% of cases. There were 31 intrapartum deaths, of which 5 were potentially salvageable.