Hamisu M. Salihu

Childbearing beyond maternal age 50 and fetal outcomes in the United States.

OBJECTIVE To estimate whether achieving pregnancy beyond maternal age of 50 years compromises fetal well-being and survival. METHODS This was a retrospective study on all deliveries in the United States from 1997 to 1999. Four maternal age groups of 20–29 (young), 30–39 (mature), 40–49 (very mature), and 50 or more years (older) were constructed to assess risk gradients for fetal morbidity and mortality. RESULTS A total of 539 deliveries among older mothers (aged 50 and above) were documented (four per 100,000). Among singleton gestations, the risks for low birth weight, preterm, and very preterm were tripled among older mothers, whereas the occurrence of very low birth weight, small size for gestational age, and fetal mortality were approximately doubled compared with those for young mothers. Older mothers also had greater risks for fetal morbidity and mortality than their immediate younger counterparts (40–49 year olds) except for very low birth weight. Among multiple gestations, the differences in risk between older and young mothers were lower than those noted among singletons. Still, compared with young mothers, older mothers had significantly higher risks of low birth weight, very low birth weight, very preterm, and small size for gestational age. Older mothers also had higher risk estimates for multiples than 40–49-year-old gravidas in terms of all fetal morbidity and mortality indices. CONCLUSION Pregnancy beyond age 50 was associated with increased risks for the fetus. Our findings suggest that this age group is a distinct obstetric high-risk entity that requires special counseling before and after conception.

Levels of excess infant deaths attributable to maternal smoking during pregnancy in the United States.

Objectives: The objectives of the study were: 1) To determine the risk of infant mortality associated with prenatal cigarette smoking; 2) To assess whether the relationship, if existent, was dose-dependent; 3) To explore the morbidity pathway that explains the effect of tobacco smoke on infant mortality, and 4) to compute excess infant deaths attributable to maternal smoking in the United States. Methods: Retrospective cohort study on 3,004,616 singleton live births that occurred in 1997 in the United States using the US national linked birth/infant death data. Excess infant deaths due to maternal smoking were computed using the population-attributable risk (PAR). Results: Overall, 13.2% of pregnant women who delivered live births in 1997 smoked during pregnancy. The rate of infant mortality was 40% higher in this group as compared to nonsmoking gravidas (P < 0.0001). This risk increased with the amount of cigarettes consumed prenatally in a dose-dependent fashion (p for trend <0.0001). Small-for-gestational age rather than preterm birth is the main mechanism through which smoking causes excess infant mortality. We estimated that about 5% of infant deaths in the United States were attributable to maternal smoking while pregnant, with variations by race/ethnicity. The proportion of infant deaths attributable to maternal smoking was highest among American Indians at 13%, almost three times the national average. If pregnant smokers were to halt tobacco use a total of 986 infant deaths would be averted annually. Conclusions: Smoking during pregnancy accounts for a sizeable number of infant deaths in the United States. This highlights the need for infusion of more resources into existing smoking cessation campaigns in order to achieve higher quit rates, and substantially diminish current levels of smoking-associated infant deaths.

Barriers to the use of antenatal and obstetric care services in rural Kano, Nigeria

The objective of this study was to identify the sociocultural and economic factors that act as barriers to womens use of antenatal care services and hospital delivery in a rural community in Kano State, Northern Nigeria. The study was based on an interview of 107 pregnant women conducted by a trained midwife in the native language of the area. Findings indicate that the majority of women (88%) (CI = 81·8-94·2%) in the study area did not attend for antenatal care, and 96·3% (CI = 93·0-99·8%) had delivered or plan to deliver at home without a skilled attendant. Major barriers identified were economic, cultural and those related to the womens perception of their condition. The study recommends that poverty reduction and economic empowerment of rural women are prerequisites for any tangible improvement in the utilisation of antenatal care and obstetric delivery services.

Maternal mortality in Northern Nigeria: a population-based study

OBJECTIVES To determine the incidence and causes of maternal mortality as well as its temporal distribution over the last decade (1990-1999). STUDY DESIGN All maternal deaths recorded within the study period in the State of Kano, Northern Nigeria, were analyzed. Maternal mortality ratios (MMR) were computed using the Poisson assumption to derive confidence intervals around the estimates. A non-linear regression model was fitted to obtain the best temporal trajectory for MMR across the decade of study. RESULTS A total of 4154 maternal deaths occurred among 171,621 deliveries, yielding an MMR of 2420 deaths per 100,000. Eclampsia, ruptured uterus and anemia were responsible for about 50% of maternal deaths. CONCLUSION We found one of the highest maternal mortality ratios in the world. Maternal mortality could be reduced by half at study site with effective interventions targeted to prevent deaths from eclampsia, ruptured uterus and anemia.

Potentially preventable excess mortality among higher-order multiples

OBJECTIVE To estimate the level of potentially preventable excess mortality achievable by avoiding the creation of higher-order multiple gestation with assisted reproductive technologies. METHODS This was a retrospective cohort study of multiple pregnancies delivered in the United States between 1995 and 1997 involving 304,466 twins, 16,068 triplets, 1448 quadruplets, and 180 quintuplets. We used the generalized estimating equation framework to compute adjusted relative risks for combined perinatal and infant mortality (early mortality). We then calculated potentially preventable excess mortality among higher-order gestations, using twins and triplets sequentially as the referent category. RESULTS Early mortality increased significantly with each additional fetus in a dose-dependent fashion (P <.001), corresponding to relative risks (95% confidence interval) of 2.4 (2.2, 2.6) for triplets, 3.3 (2.5, 4.4) for quadruplets, and 10.3 (5.0, 21.4) for quintuplets. The creation of twin rather than quadruplet pregnancies would be associated with a substantially higher level of preventable excess mortality (70%) than the creation of triplet pregnancies (28%). By contrast, limiting quintuplets to twins or triplets did not exhibit a similar level of difference (89% versus 75%, respectively). CONCLUSIONS Our findings support the need for regulating the number of transferred embryos that result in quadruplet and quintuplet pregnancies.

Significant paternal contribution to the risk of small for gestational age

Objective  The aim of this study is to investigate both maternal and paternal contributions in the familial aggregation of small for gestational age.

The impact of maternal mortality interventions using traditional birth attendants and village midwives

Traditional birth attendants (TBAs) and village midwives have been employed in many interventions to reduce maternal mortality in developing countries. This study reviews the results of 15 TBA- and midwife-based interventions that aim to improve skilled assistance in delivery and recognition and referral of complications. Outcome measures used to evaluate the impact of the programmes varied. Five of the five programmes reviewed that evaluated their impact on maternal mortality demonstrated a decline in maternal mortality ratios, two of three studies measuring morbidity-related indicators found improvement of some but not all morbidity outcomes, six of seven showed a trend of improved referral rates, and three of three found high levels of knowledge retention among trained TBAs. Programmes with the greatest impact utilised TBAs and village midwives within multisectoral interventions. These findings suggest that TBAs and village midwives contribute to positive programme outcomes. Further investigation is needed to determine the nature of their contribution within larger programmes.

Mode of delivery and birth outcomes of macrosomic infants

This review examines and summarises the literature regarding the mode of delivery of macrosomic infants and subsequent perinatal outcomes. A search of electronic databases was conducted and supplemented with investigation of the references cited in the original articles. Although the rates of obstetric complications differ among high birth weight infants delivered by caesarean section compared to those delivered vaginally, there is currently little evidence that perinatal mortality differs significantly by delivery method. Shoulder dystocia and birth injury occur with greater frequency among macrosomic infants, yet the relative inaccuracy of clinical and ultrasonographic estimates of birth weight among high birth weight infants indicates that a trial of labour may be warranted among non-diabetic mothers with a suspected macrosomic fetus. The majority of studies identified in this review utilised small sample sizes and observational design, thereby hindering valid assessments of the impact of delivery method on the mortality of this population. Consequently, an optimal management strategy has yet to be defined.

Omphalocele and gastrochisis

Between January 1989 and November 1996 we detected a total of 44 cases of anterior abdominal wall defects comprising 29 with an omphalocele and 15 with gastrochisis. The gestational age at antenatal diagnosis of gastrochisis (mean = 17 weeks, 95% CI = 15-19) was significantly lower than for omphalocele (mean = 19·0 weeks, 95% CI = 17-21). Whereas gastrochisis tended to occur in relatively younger mothers (mean age = 23 years), omphalocele was associated with a comparatively advanced maternal age (mean age = 28 years). The sensitivity of ultrasound detection was the same for both malformations (omphalocele = 86·2%; gastrochisis = 86·7%). Additional structural anomalies were found in a higher proportion of those with an omphalocele compared with those with gastrochisis (62% vs. 20%). All the three cases of chromosomal anomalies were detected in omphalocele fetuses with an intracorporeal liver. Perinatal mortality was higher, albeit nonsignificantly, among fetuses with omphalocele.

Prenatal Tobacco Use and Risk of Stillbirth: A Case—Control and Bidirectional Case—Crossover Study

We sought to estimate the association between prenatal smoking and stillbirth in a longitudinal cohort using two study designs: a case-control study and a bidirectional case-crossover study. The analysis was conducted using the Missouri maternally linked cohort dataset from 1978 through 1997. In the case-control study, each mother contributed only one birth to the analysis. For the bidirectional crossover design, analysis was restricted to women who gave birth to at least one stillbirth, and the controls comprised all live births before and after the stillbirth. The independent association between prenatal smoking and stillbirth was computed using nonconditional (case-control design) and conditional (bidirectional case-crossover design) logistic regression. Prenatal smoking decreased from 29.7% in 1978 to 21.2% by 1997 (p<.001). The absolute risk of stillbirth was greater among smokers (7.7/1000) than nonsmokers (5.3/1000), p<.001. In the case-control design, the risk of stillbirth was 34% greater among smokers than nonsmokers (OR = 1.34, 95% CI 1.26-1.43). For each 10-unit increase in the number of cigarettes consumed per day prenatally, the likelihood of stillbirth rose by about 14% (p<.001). In the bidirectional case-crossover design, the association between stillbirth and smoking during pregnancy was confirmed, although the magnitude of the relationship was smaller (OR = 1.20, 95% CI 1.03-1.39). In conclusion, we found prenatal smoking to be a risk factor for stillbirth even after minimizing the influence of known and unknown sources of confounding as well as changes in temporal trend in prenatal smoking.