Prognostic factors for low birthweight repetition in successive pregnancies: a cohort study.
BACKGROUND
To identify prognostic factors associated with recurrence of low birthweight (LBW) in successive gestations, a study was carried out with a subsample of mothers enrolled in the 2004 Pelotas Birth Cohort.


METHODS
Data were collected by hospital-based interviews. Newborns were weighed and measured. Gestational age was defined according to the date of last menstrual period, ultra-sound scan before the 20th week of pregnancy or the Dubowitz method. Mothers who reported at least one LBW newborn in the two previous gestations were included. Prevalence ratios (PR) and 95% confidence intervals were estimated from Poisson Regression. All estimates were adjusted for parity.


RESULTS
A total of 4558 births were identified in 2004, and 565 met inclusion criteria, out of which 86 (15.2%) repeated LBW in 2004. Among mothers with two LBW babies before 2004, 47.9% presented LBW recurrence. Belonging to the highest socio-economic stratum (PR 0.89; 0.01-0.46) and gaining ≥ 10 kg during pregnancy (PR 0.09; 0.01-0.77) were protective against LBW recurrence. Higher risk of LBW recurrence was observed among mothers with higher parity (≥3 previous deliveries; PR=1.93; 95% CI 1.23-3.02); who had given birth to a previous preterm baby (PR=4.01; 2.27-7.10); who delivered a female newborn in current gestation (PR=2.61; 1.45-4.69); and that had not received adequate antenatal care (PR=2.57; 1-37-4.81).


CONCLUSIONS
Improved quality of antenatal care and adequate maternal weight gain during pregnancy may be feasible strategies to prevent LBW repetition in successive pregnancies.
Post-graduate Program in Epidemiology, Departamento de Medicina Social, Faculdade de Medicina, Federal University of Pelotas, Pelotas, Brazil.
Iândora Krolow Timm
IK
Sclowitz
Iná S
IS
Santos
Marlos Rodrigues
MR
Domingues
Alicia
A
Matijasevich
Aluísio J D
AJ
Barros
D000328:Adult; D001938:Brazil / Q000453:epidemiology; D015331:Cohort Studies; D005260:Female; D005865:Gestational Age; D006801:Humans; D007230:Infant, Low Birth Weight / Q000502:physiology*; D007231:Infant, Newborn; D010298:Parity; D016012:Poisson Distribution; D011247:Pregnancy; D047928:Premature Birth / Q000453:epidemiology* / Q000517:prevention & control; D011295:Prenatal Care / Q000379:methods* / Q000706:statistics & numerical data; D015995:Prevalence; D011379:Prognosis; D012008:Recurrence; D012307:Risk Factors; D012959:Socioeconomic Factors; D015430:Weight Gain / Q000502:physiology