The influence of maternal body composition on birth weight.

OBJECTIVE: To identify the maternal body composition parameters that independently influence birth weight. STUDY DESIGN: A longitudinal prospective observational study in a large university teaching hospital. One hundred and eighty-four non-diabetic caucasian women with a singleton pregnancy were studied. In early pregnancy maternal weight and height were measured digitally in a standardised way and the body mass index (BMI) was calculated. At 28 and 37 weeks' gestation maternal body composition was assessed using segmental multifrequency bioelectrical impedance analysis. At delivery the baby was weighed and the clinical details were recorded. RESULTS: Of the women studied, 29.2% were overweight and 34.8% were obese. Birth weight did not correlate with maternal weight or BMI in early pregnancy. Birth weight correlated with gestational weight gain (GWG) before the third trimester (r=0.163, p=0.027), but not with GWG in the third trimester. Birth weight correlated with maternal fat-free mass, and not fat mass at 28 and 37 weeks gestation. Birth weight did not correlate with increases in maternal fat and fat-free masses between 28 and 37 weeks. CONCLUSIONS: Contrary to previous reports, we found that early pregnancy maternal BMI in a non-diabetic population does not influence birth weight. Interestingly, it was the GWG before the third trimester and not the GWG in the third trimester that influenced birth weight. Our findings have implications for the design of future intervention studies aimed at optimising gestational weight gain and birth weight. CONDENSATION: Maternal fat-free mass and gestational weight gain both influence birth weight.

Neonatal brachial plexus palsy: an unpredictable injury.

OBJECTIVE: Brachial plexus paralysis is a serious form of neonatal morbidity. We determined its incidence and persistence of disability and evaluated whether its occurrence could be predicted by maternal characteristics or partographic analysis in a large cohort of recent cases. STUDY DESIGN: During the years 1994 through 1998, all infants with neonatal evidence of obstetric brachial plexus injury were identified and followed 14;>or=1 year. Obstetric details in these maternal-infant pairs were compared with 108 control pairs, matched for maternal and gestational age, parity, and birth weight. Partographs of cases and control subjects were reviewed, in a blinded manner, by 3 obstetricians who were asked to identify likely cases of nerve injury. A risk score comprising eight recognized associated clinical features was assigned. RESULTS: Fifty-four of 35,796 infants (1.5/1000) had evidence of brachial plexus injury; in 10 cases (19%), neurologic deficit persisted to 1 year. Although the risk factor profile was relatively higher in cases compared with control subjects, the highest score was 5 of 8 in six cases (2 cases, 4 control subjects). Obstetricians' partographic assessment identified "likely brachial plexus injury" in 13 of 54 cases (24%) and 16 of 108 control subjects (15%), and in only 3 cases (6%) did the assessors concur (positive predictive value, 7%-17%; negative predictive value, 5%-12%; sensitivity, 24%-50%; specificity, 66%-68%). Risk scores were similar among persistently and transiently injured cases. CONCLUSION: Our results indicate that brachial plexus injury is not predictable before delivery, either by risk factor scoring or by partographic analysis.