Perspective cohort study to determine the effects of parental age, height, weight, BMI, and parity on the birth weight and length in uncomplicated single ton pregnancies

Abstract

To determine the relationship of parental height, weight, BMI, age, and parity on the weight and length of the neonate. Prospective cohort study. Setting: Obstetrics and Gynaecology Units Castle Street Hospital for Women, Colombo . 825 women with uncomplicated singleton pregnancies, their partners and newborn babies in the indexed pregnancy. Main outcome measures: Birth weight, birth length, Ponderal index, and placental weight. We studied 825 expecting women, 53.5 percent nulliparous, 29.8 percent para I, 12.7 percent para 2 and 4.0 percent para three or more. Age distribution was Mean±SD= 28.9±5.1 years, Median=29 years and ranged from 18 to 43 years. Their height weight and BMI were 156,1±6.5cm, 53.1±9.6kg, and 21.8±3.7 respectively. In the BMI groups there were 64.4 percent normal, underweightI7.8 percent overweight 14.5 percent and 3.3 percent obese. First trimester Hb concentration was 11.7± l.4g/dl. First trimester USS was done in only 25.5 percent and by 22 weeks 53.1 percent had USS. Gestation at delivery was 273.1±18.\ days. Paternal age, height, weight and BMI were 32.3±5.5 years, 162.2 ±7.2cm, 63.6± 11.8kg, and 22.5±4.0. 62.8 percent delivered vaginally out of which 4.7 percent were instrumental and 37.2 percent had caesarean delivery. There were 52.7 percent male babies delivered. Mean birth weights for all was 2987±400g and for male and female babies 3032±397g and 2936±399g respectively. Mean length of the babies was 51.62±3.9cm. Birth weight correlated with maternal height ( r=0.21, p=0.001, 2-tailed), maternal weight, weight gain ( r=0.09,p=0.005, 2-tailed), maternal BMI category ( F=7.5, p 0.001). Maternal and paternal height, weight, and BMI and parity influence the birth weight in uncomplicated term pregnancies. Maternal parameters have more effects than the paternal