The application of individualised fetal growth curves

Risk factors for intrauterine growth restriction in a socio-economically disadvantaged region

BACKGROUND

Risk factors for pregnancies being complicated by the birth of a small-for-gestational age (SGA) infant were analysed in a socio-economically disadvantaged area, with separate analysis for population-based and customized-based birth weight percentiles.

METHODS

A retrospective case-controlled study of all singleton pregnancies resulting in the birth of an infant with a birth weight < 10 population-based centile, born in the Northern suburbs of metropolitan Adelaide, between 1998 and 2003. Significant risk factors in the univariate analysis were subsequently checked with multivariate analysis.

RESULTS

The analyses confirm marked differences between population-based and customized-birth weight centiles. Patterns of risk factors show clear differences in risk factors for these two different SGA groups. Univariate analyses of all (nulliparous and multiparous women) customized SGA infants shows us the following odds ratio's (OR); unemployment OR 2.06, 95% confidence interval (CI) 1.46-2.92, being a single mother OR 1.90, CI 1.76-2.05, smoking OR 3.24, CI 2.32 - 4.54, recreational drug use OR 2.40, CI 1.55-3.70, mental health problems OR 1.52, CI 1.04-2.23, domestic violence OR 3.42, CI 1.26-9.29, being healthy OR 0.43, CI 0.30-0.61, preeclampsia OR 1.73, CI 1.01-2.97, and BMI < 30 OR 0.63 CI 0.43-0.93. Length of pregnancy interval had no relationship whatsoever with the risk of being delivered of an SGA infant. Multivariate analyses for customized SGA showed five factors with an OR > 2 (95% CI not crossing 1), including unemployment, smoking, maternal age > 34 years, not being healthy and preeclampsia, while different paternity, age 25-34 compared to age < 25 were also found to be significant risk factors. Higher systolic blood pressure was found to convey significant protection.

CONCLUSION

When studying risk factors for pregnancies complicated by the birth of an SGA infant, both population-derived and customized growth centiles should be utilized. This study confirms the importance of smoking as a major risk factor, our data also show major protection being conveyed by having a regular job and being generally healthy. Pregnancy interval did not have any relationship with the birth of SGA infants, while paternity change was identified as a clear risk factor. Although genuine preeclampsia persists as a clear risk factor, higher systolic blood pressure appears to convey protection.

Excessive stimulation of poly(ADP-ribosyl)ation contributes to endothelial dysfunction in pre-eclampsia

1. Pre-eclampsia is a serious pregnancy disorder associated with widespread activation of the maternal vascular endothelium. Recent evidence implicates a role for oxidative stress in the aetiology of this condition. 2. Reactive oxygen species, particularly superoxide anions, invokes endothelial cell activation through many pathways. Oxidant-induced cell injury triggers the activation of nuclear enzyme poly(ADP-ribose) polymerase (PARP) leading to endothelial dysfunction in various pathophysiological conditions (reperfusion, shock, diabetes). 3. We have studied whether the loss of endothelial function in pre-eclampsia is dependent on PARP activity. Endothelium-dependent responses of myometrial arteries were tested following exposure to either plasma from women with pre-eclampsia or normal pregnant women in the presence and absence of a novel potent inhibitor of PARP, PJ34. Additional effects of plasma and PJ34 inhibition were identified in microvascular endothelial cell cultures. 4. In myometrial arteries, PARP inhibition blocked the attenuation of endothelium-dependent responses following exposure to plasma from women with pre-eclampsia. In endothelial cell cultures, plasma from pre-eclamptics induced measurable oxidative stress and a concomitant increase in PARP activity and reduction in cellular ATP. Again, these biochemical changes were reversed by PJ34. 5. These results suggest that PARP activity plays a pathogenic role in the development of endothelial dysfunction in pre-eclampsia and promotes PARP inhibition as a potential therapy in this condition.

Ethnic variations in birthweight percentiles in Kuwait

The objectives of this retrospective study were to assess the effect of ethnicity on birthweight percentiles and to compare ethnic-specific percentiles with other references. Analysis was made of 35 768 singleton live births from 22 to 44 completed weeks of gestation at two major obstetric hospitals in Kuwait, after exclusion of data with inaccurate gestational age, major congenital abnormalities, stillbirths, and outlying birthweights. The population included four major ethnic groups: Gulf Arabs, Mediterranean Arabs, Egyptians, and a group combining Indians and Southeast Asians. Total population and ethnic-specific smoothed birthweight percentiles according to gestational age were developed. Indians-Asians had the smallest birthweights, the highest prevalence of small-for-gestational-age (SGA) birthweights and the lowest prevalence of large-for-gestational-age (LGA) birthweights. On the contrary, Egyptians had the largest birthweights, the lowest prevalence of SGA birthweights and the highest prevalence of LGA birthweights. Plotting our birthweights on a reference from Canada resulted in a low prediction rate for SGA and a low sensitivity in identifying LGA of all ethnic groups. We conclude that interpretation of fetal growth and birthweight should involve locally derived and ethnically specific percentiles based on accurately calculated gestational age.